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Sample records for bemisia tabaci genome

  1. Draft genome sequence of "Candidatus Hamiltonella defensa," an endosymbiont of the whitefly Bemisia tabaci.

    PubMed

    Rao, Qiong; Wang, Shuang; Su, Yun-Lin; Bing, Xiao-Li; Liu, Shu-Sheng; Wang, Xiao-Wei

    2012-07-01

    "Candidatus Hamiltonella defensa" is a facultative endosymbiont of the whitefly Bemisia tabaci. Herein, we report the first draft genome sequence of "Candidatus Hamiltonella defensa" from the invasive Mediterranean cryptic species of the B. tabaci complex. The 1.84-Mbp genome sequence comprises 404 contigs and contains 1,806 predicted protein-coding genes.

  2. Genome sequencing of the sweet potato whitefly Bemisia tabaci MED/Q

    USDA-ARS?s Scientific Manuscript database

    Crypic and invasive species of whitefly, Bemisia tabaci, are highly destructive agricultural and ornamental crop pest that as a group cause direct feeding damage to host plants and vector a large number of harmful plant viruses. Introductions of B. tabaci are difficult to quarantine and eradicate d...

  3. Genome-Wide Characterization and Expression Profiling of Sugar Transporter Family in the Whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae).

    PubMed

    Yang, Zezhong; Xia, Jixing; Pan, Huipeng; Gong, Cheng; Xie, Wen; Guo, Zhaojiang; Zheng, Huixin; Yang, Xin; Yang, Fengshan; Wu, Qingjun; Wang, Shaoli; Zhang, Youjun

    2017-01-01

    Sugar transporters (STs) play pivotal roles in the growth, development, and stress responses of phloem-sucking insects, such as the whitefly, Bemisia tabaci. In this study, 137 sugar transporters (STs) were identified based on analysis of the genome and transcriptome of B. tabaci MEAM1. B. tabaci MEAM1 encodes a larger number of STs than other selected insects. Phylogenetic and molecular evolution analysis showed that the 137 STs formed three expanded clades and that the genes in Sternorrhyncha expanded clades had accelerated rates of evolution. B. tabaci sugar transporters (BTSTs) were divided into three groups based on their expression profiles across developmental stages; however, no host-specific BTST was found in B. tabaci fed on different host plants. Feeding of B. tabaci adults with feeding diet containing dsRNA significantly reduced the transcript level of the target genes in B. tabaci and mortality was significantly improved in B. tabaci fed on dsRNA compared to the control, which indicates the sugar transporters may be used as potential RNAi targets for B. tabaci bio-control. These results provide a foundation for further studies of STs in B. tabaci.

  4. Genome-Wide Characterization and Expression Profiling of Sugar Transporter Family in the Whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae)

    PubMed Central

    Yang, Zezhong; Xia, Jixing; Pan, Huipeng; Gong, Cheng; Xie, Wen; Guo, Zhaojiang; Zheng, Huixin; Yang, Xin; Yang, Fengshan; Wu, Qingjun; Wang, Shaoli; Zhang, Youjun

    2017-01-01

    Sugar transporters (STs) play pivotal roles in the growth, development, and stress responses of phloem-sucking insects, such as the whitefly, Bemisia tabaci. In this study, 137 sugar transporters (STs) were identified based on analysis of the genome and transcriptome of B. tabaci MEAM1. B. tabaci MEAM1 encodes a larger number of STs than other selected insects. Phylogenetic and molecular evolution analysis showed that the 137 STs formed three expanded clades and that the genes in Sternorrhyncha expanded clades had accelerated rates of evolution. B. tabaci sugar transporters (BTSTs) were divided into three groups based on their expression profiles across developmental stages; however, no host-specific BTST was found in B. tabaci fed on different host plants. Feeding of B. tabaci adults with feeding diet containing dsRNA significantly reduced the transcript level of the target genes in B. tabaci and mortality was significantly improved in B. tabaci fed on dsRNA compared to the control, which indicates the sugar transporters may be used as potential RNAi targets for B. tabaci bio-control. These results provide a foundation for further studies of STs in B. tabaci. PMID:28588501

  5. Genome reduction and potential metabolic complementation of the dual endosymbionts in the whitefly Bemisia tabaci.

    PubMed

    Rao, Qiong; Rollat-Farnier, Pierre-Antoine; Zhu, Dan-Tong; Santos-Garcia, Diego; Silva, Francisco J; Moya, Andrés; Latorre, Amparo; Klein, Cecilia C; Vavre, Fabrice; Sagot, Marie-France; Liu, Shu-Sheng; Mouton, Laurence; Wang, Xiao-Wei

    2015-03-21

    The whitefly Bemisia tabaci is an important agricultural pest with global distribution. This phloem-sap feeder harbors a primary symbiont, "Candidatus Portiera aleyrodidarum", which compensates for the deficient nutritional composition of its food sources, and a variety of secondary symbionts. Interestingly, all of these secondary symbionts are found in co-localization with the primary symbiont within the same bacteriocytes, which should favor the evolution of strong interactions between symbionts. In this paper, we analyzed the genome sequences of the primary symbiont Portiera and of the secondary symbiont Hamiltonella in the B. tabaci Mediterranean (MED) species in order to gain insight into the metabolic role of each symbiont in the biology of their host. The genome sequences of the uncultured symbionts Portiera and Hamiltonella were obtained from one single bacteriocyte of MED B. tabaci. As already reported, the genome of Portiera is highly reduced (357 kb), but has kept a number of genes encoding most essential amino-acids and carotenoids. On the other hand, Portiera lacks almost all the genes involved in the synthesis of vitamins and cofactors. Moreover, some pathways are incomplete, notably those involved in the synthesis of some essential amino-acids. Interestingly, the genome of Hamiltonella revealed that this secondary symbiont can not only provide vitamins and cofactors, but also complete the missing steps of some of the pathways of Portiera. In addition, some critical amino-acid biosynthetic genes are missing in the two symbiotic genomes, but analysis of whitefly transcriptome suggests that the missing steps may be performed by the whitefly itself or its microbiota. These data suggest that Portiera and Hamiltonella are not only complementary but could also be mutually dependent to provide a full complement of nutrients to their host. Altogether, these results illustrate how functional redundancies can lead to gene losses in the genomes of the different

  6. Complete mitochondrial DNA genome of Bemisia tabaci cryptic pest species complex Asia I (Hemiptera: Aleyrodidae).

    PubMed

    Tay, W T; Elfekih, S; Court, L; Gordon, K H; De Barro, P J

    2016-01-01

    The complete length of the Asia I member of the Bemisia tabaci species complex mitochondrial DNA genome (mitogenome) is 15,210 bp (GenBank accession no. KJ778614) with an A-T biased nucleotide composition (A: 32.7%; T: 42.4%; G: 14.0%; C: 10.8%). The mitogenome consists of 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), 2 ribosomal RNA (rRNAs) and a 467 bp putative control region which also includes the A+T rich repeat region. All PCGs have an ATA (n = 8) or ATG (n = 5) start codon. Gene synteny of Asia I is overall similar to B. afer and two other members of the B. tabaci species complex Mediterranean and New World 1, and contains the tRNA-Ser2 located between the Cytb and ND1 genes found in Mediterranean and New World 1, but which is absent in B. afer. The orientation of the tRNA-Arg in Asia I is on the "plus" strand and differed from Mediterranean which is found on the "minus" strand. The Asia I mitogenome size is currently ranked the second smallest after B. afer (14,968 bp) followed by New World 1 (15,322 bp) and Mediterranean (15,632 bp).

  7. Estimation of the Whitefly Bemisia tabaci Genome Size Based on k-mer and Flow Cytometric Analyses.

    PubMed

    Chen, Wenbo; Hasegawa, Daniel K; Arumuganathan, Kathiravetpillai; Simmons, Alvin M; Wintermantel, William M; Fei, Zhangjun; Ling, Kai-Shu

    2015-07-28

    Whiteflies of the Bemisia tabaci (Hemiptera: Aleyrodidae) cryptic species complex are among the most important agricultural insect pests in the world. These phloem-feeding insects can colonize over 1000 species of plants worldwide and inflict severe economic losses to crops, mainly through the transmission of pathogenic viruses. Surprisingly, there is very little genomic information about whiteflies. As a starting point to genome sequencing, we report a new estimation of the genome size of the B. tabaci B biotype or Middle East-Asia Minor 1 (MEAM1) population. Using an isogenic whitefly colony with over 6500 haploid male individuals for genomic DNA, three paired-end genomic libraries with insert sizes of ~300 bp, 500 bp and 1 Kb were constructed and sequenced on an Illumina HiSeq 2500 system. A total of ~50 billion base pairs of sequences were obtained from each library. K-mer analysis using these sequences revealed that the genome size of the whitefly was ~682.3 Mb. In addition, the flow cytometric analysis estimated the haploid genome size of the whitefly to be ~690 Mb. Considering the congruency between both estimation methods, we predict the haploid genome size of B. tabaci MEAM1 to be ~680-690 Mb. Our data provide a baseline for ongoing efforts to assemble and annotate the B. tabaci genome.

  8. Estimation of the Whitefly Bemisia tabaci Genome Size Based on k-mer and Flow Cytometric Analyses

    PubMed Central

    Chen, Wenbo; Hasegawa, Daniel K.; Arumuganathan, Kathiravetpillai; Simmons, Alvin M.; Wintermantel, William M.; Fei, Zhangjun; Ling, Kai-Shu

    2015-01-01

    Whiteflies of the Bemisia tabaci (Hemiptera: Aleyrodidae) cryptic species complex are among the most important agricultural insect pests in the world. These phloem-feeding insects can colonize over 1000 species of plants worldwide and inflict severe economic losses to crops, mainly through the transmission of pathogenic viruses. Surprisingly, there is very little genomic information about whiteflies. As a starting point to genome sequencing, we report a new estimation of the genome size of the B. tabaci B biotype or Middle East-Asia Minor 1 (MEAM1) population. Using an isogenic whitefly colony with over 6500 haploid male individuals for genomic DNA, three paired-end genomic libraries with insert sizes of ~300 bp, 500 bp and 1 Kb were constructed and sequenced on an Illumina HiSeq 2500 system. A total of ~50 billion base pairs of sequences were obtained from each library. K-mer analysis using these sequences revealed that the genome size of the whitefly was ~682.3 Mb. In addition, the flow cytometric analysis estimated the haploid genome size of the whitefly to be ~690 Mb. Considering the congruency between both estimation methods, we predict the haploid genome size of B. tabaci MEAM1 to be ~680–690 Mb. Our data provide a baseline for ongoing efforts to assemble and annotate the B. tabaci genome. PMID:26463411

  9. Genome-wide analysis of ATP-binding cassette (ABC) transporters in the sweetpotato whitefly, Bemisia tabaci.

    PubMed

    Tian, Lixia; Song, Tianxue; He, Rongjun; Zeng, Yang; Xie, Wen; Wu, Qingjun; Wang, Shaoli; Zhou, Xuguo; Zhang, Youjun

    2017-04-26

    ABC transporter superfamily is one of the largest and ubiquitous groups of proteins. Because of their role in detoxification, insect ABC transporters have gained more attention in recent years. In this study, we annotated ABC transporters from a newly sequenced sweetpotato whitefly genome. Bemisia tabaci Q biotype is an emerging global invasive species that has caused extensive damages to field crops as well as ornamental plants. A total of 55 ABC transporters containing all eight described subfamilies (A to H) were identified in the B. tabaci Q genome, including 8 ABCAs, 3 ABCBs, 6 ABCCs, 2 ABCDs, 1 ABCE, 3 ABCFs, 23 ABCGs and 9 ABCHs. In comparison to other species, subfamilies G and H in both phloem- and blood-sucking arthropods are expanded. The temporal expression profiles of these 55 ABC transporters throughout B. tabaci developmental stages and their responses to imidacloprid, a neonicotinoid insecticide, were investigated using RNA-seq analysis. Furthermore, the mRNA expression of 24 ABC transporters (44% of the total) representing all eight subfamilies was confirmed by the quantitative real-time PCR (RT-qPCR). Furthermore, mRNA expression levels estimated by RT-qPCR and RNA-seq analyses were significantly correlated (r = 0.684, p < 0.01). It is the first genome-wide analysis of the entire repertoire of ABC transporters in B. tabaci. The identification of these ABC transporters, their temporal expression profiles during B. tabaci development, and their response to a neonicotinoid insecticide lay the foundation for functional genomic understanding of their contribution to the invasiveness of B. tabaci.

  10. Flow cytometry and K-mer analysis estimates of the genome sizes of Bemisia tabaci B and Q (Hemiptera: Aleyrodidae)

    PubMed Central

    Guo, Li T.; Wang, Shao L.; Wu, Qing J.; Zhou, Xu G.; Xie, Wen; Zhang, You J.

    2015-01-01

    The genome sizes of the B- and Q-types of the whitefly Bemisia tabaci (Gennnadius) were estimated using flow cytometry (Drosophila melanogaster as the DNA reference standard and propidium iodide (PI) as the fluorochrome) and k-mer analysis. For flow cytometry, the mean nuclear DNA content was 0.686 pg for B-type males, 1.392 pg for B-type females, 0.680 pg for Q-type males, and 1.306 pg for Q-type females. Based on the relationship between DNA content and genome size (1 pg DNA = 980 Mbp), the haploid genome size of B. tabaci ranged from 640 to 682 Mbp. For k-mer analysis, genome size of B-type by two methods were consistent highly, but the k-mer depth distribution graph of Q-type was not enough perfect and the genome size was estimated about 60 M larger than its flow cytometry result. These results corroborate previous reports of genome size based on karyotype analysis and chromosome counting. However, these estimates differ from previous flow cytometry estimates, probably because of differences in the DNA reference standard and dyeing time, which were superior in the current study. For Q-type genome size difference by two method, some discussion were also stated, and all these results represent a useful foundation for B. tabaci genomics research. PMID:26042041

  11. The draft genome of whitefly Bemisia tabaci MEAM1, a global crop pest, provides novel insights into virus transmission, host adaptation, and insecticide resistance

    USDA-ARS?s Scientific Manuscript database

    Whiteflies are among the most important agricultural pests. They have a broad range of host plants and exceptional ability to transmit a large number of plant viruses, and can rapidly evolve insecticide resistance. Here we present a high-quality draft genome of the whitefly, Bemisia tabaci. Comparat...

  12. Estimation of the whitefly Bemisia tabaci genome size based on k-mer and flow cytometry analyses

    USDA-ARS?s Scientific Manuscript database

    Whiteflies, Bemisia tabaci (Hemiptera: Aleyrodidae), are one of the most important agricultural insect pests in the world. These phloem-feeding insects can colonize over 500 crop plants worldwide and inflict severe economic losses, mainly through the transmission of pathogenic viruses. Surprisingl...

  13. Genome sequencing and analysis of the whitefly (Bemisia tabaci) MEAM1, one of the most important vectors for plant viruses

    USDA-ARS?s Scientific Manuscript database

    Among whiteflies, the Bemisia tabaci (Hemiptera: Aleyrodidae) species complex is particularly important because of its ability to transmit hundreds of plant viruses, resulting in the loss of billions of U.S. dollars on agronomically important crops such as tomato, cucurbits, cassava, and cotton worl...

  14. Sequencing and comparison of the Rickettsia genomes from the whitefly Bemisia tabaci Middle East Asia Minor I.

    PubMed

    Zhu, Dan-Tong; Xia, Wen-Qiang; Rao, Qiong; Liu, Shu-Sheng; Ghanim, Murad; Wang, Xiao-Wei

    2016-08-01

    The whitefly, Bemisia tabaci, harbors the primary symbiont 'Candidatus Portiera aleyrodidarum' and a variety of secondary symbionts. Among these secondary symbionts, Rickettsia is the only one that can be detected both inside and outside the bacteriomes. Infection with Rickettsia has been reported to influence several aspects of the whitefly biology, such as fitness, sex ratio, virus transmission and resistance to pesticides. However, mechanisms underlying these differences remain unclear, largely due to the lack of genomic information of Rickettsia. In this study, we sequenced the genome of two Rickettsia strains isolated from the Middle East Asia Minor 1 (MEAM1) species of the B. tabaci complex in China and Israel. Both Rickettsia genomes were of high coding density and AT-rich, containing more than 1000 coding sequences, much larger than that of the coexisted primary symbiont, Portiera. Moreover, the two Rickettsia strains isolated from China and Israel shared most of the genes with 100% identity and only nine genes showed sequence differences. The phylogenetic analysis using orthologs shared in the genus, inferred the proximity of Rickettsia in MEAM1 and Rickettsia bellii. Functional analysis revealed that Rickettsia was unable to synthesize amino acids required for complementing the whitefly nutrition. Besides, a type IV secretion system and a number of virulence-related genes were detected in the Rickettsia genome. The presence of virulence-related genes might benefit the symbiotic life of the bacteria, and hint on potential effects of Rickettsia on whiteflies. The genome sequences of Rickettsia provided a basis for further understanding the function of Rickettsia in whiteflies. © 2016 Institute of Zoology, Chinese Academy of Sciences.

  15. Whitefly (Bemisia tabaci) management program for ornamental plants

    USDA-ARS?s Scientific Manuscript database

    Bemisia tabaci (Gennadius) commonly known as silverleaf whitefly, is a polyphagous pest considered to be one of the most notorious invasive arthropods worldwide. The pest status of Bemisia tabaci is complicated because of their well debated taxonomic architecture which was previously identified to c...

  16. The Genome of Cardinium cBtQ1 Provides Insights into Genome Reduction, Symbiont Motility, and Its Settlement in Bemisia tabaci

    PubMed Central

    Santos-Garcia, Diego; Rollat-Farnier, Pierre-Antoine; Beitia, Francisco; Zchori-Fein, Einat; Vavre, Fabrice; Mouton, Laurence; Moya, Andrés; Latorre, Amparo; Silva, Francisco J.

    2014-01-01

    Many insects harbor inherited bacterial endosymbionts. Although some of them are not strictly essential and are considered facultative, they can be a key to host survival under specific environmental conditions, such as parasitoid attacks, climate changes, or insecticide pressures. The whitefly Bemisia tabaci is at the top of the list of organisms inflicting agricultural damage and outbreaks, and changes in its distribution may be associated to global warming. In this work, we have sequenced and analyzed the genome of Cardinium cBtQ1, a facultative bacterial endosymbiont of B. tabaci and propose that it belongs to a new taxonomic family, which also includes Candidatus Amoebophilus asiaticus and Cardinium cEper1, endosymbionts of amoeba and wasps, respectively. Reconstruction of their last common ancestors’ gene contents revealed an initial massive gene loss from the free-living ancestor. This was followed in Cardinium by smaller losses, associated with settlement in arthropods. Some of these losses, affecting cofactor and amino acid biosynthetic encoding genes, took place in Cardinium cBtQ1 after its divergence from the Cardinium cEper1 lineage and were related to its settlement in the whitefly and its endosymbionts. Furthermore, the Cardinium cBtQ1 genome displays a large proportion of transposable elements, which have recently inactivated genes and produced chromosomal rearrangements. The genome also contains a chromosomal duplication and a multicopy plasmid, which harbors several genes putatively associated with gliding motility, as well as two other genes encoding proteins with potential insecticidal activity. As gene amplification is very rare in endosymbionts, an important function of these genes cannot be ruled out. PMID:24723729

  17. The Bemisia tabaci (Hemiptera: Aleyrodidae) as a pest in Egypt

    USDA-ARS?s Scientific Manuscript database

    Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) has many common names including sweetpotato whitefly, silverleaf whitefly, tobacco whitefly, tomato whitefly, and cassava whitefly. It is an important global pest of numerous field and greenhouse agricultural crops. It damages plants from its fee...

  18. Effect of climate change on Bemisia tabaci in southeast USA

    USDA-ARS?s Scientific Manuscript database

    Introduction: Among species of whiteflies on a global scale, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is by far the most problematic in agricultural. The status of B. tabaci as a challenging global pest problem resulted in part because of its role as a vector of numerous plant viruses, a...

  19. Natural Enemies of Bemisia tabaci: Predators and Parasitiods

    USDA-ARS?s Scientific Manuscript database

    The sweetpotato whitefly, Bemisia tabaci (Gennadius), is a worldwide problem in numerous agricultural crops. The known parasitoids of B. tabaci include 43 species of Encarsia, 19 Eretmocerus, and a few other genera. Some of these species are more cosmopolitan than others. Work has been conducted ...

  20. Ecological determinants of resistance to insecticides in Bemisia tabaci

    USDA-ARS?s Scientific Manuscript database

    Insecticide resistance is a critical issue in pest management and has often been implicated as the primary cause of outbreaks of the global whitefly pest Bemisia tabaci Gennadius. Resistance to all modes of action used commonly against B. tabaci has been documented in various locations throughout t...

  1. Buprofezin inhibits acetylcholinesterase activity in B-biotype Bemisia tabaci.

    PubMed

    Cottage, Emma L A; Gunning, Robin V

    2006-01-01

    B-biotype Bemisia tabaci is a severe insect pest worldwide in many ornamental, agricultural, and horticultural industries. Control of this insect is hampered by resistance to many acetylcholinesterase (AChE)-inhibiting insecticides, such as organophosphates and carbamates. Consequently, insect growth regulators such as buprofezin, which act by inhibiting chitin synthesis, are being investigated for use against B-biotype B. tabaci in Australia. This study discusses the effects of buprofezin on B. tabaciAChE.

  2. Long term dynamics of aphelinid parasitoids attacking Bemisia tabaci

    USDA-ARS?s Scientific Manuscript database

    Aphelinid parasitoids are widely known natural enemies of Bemisia tabaci, a serious pest of agriculture globally. Here we examine pest and parasitoid interactions and dynamics in cotton from 1996–2010, during which a classical biological control program was underway. Two native species, Eremocerus e...

  3. Effect of climate change on Bemisia tabaci in Southeastern USA

    USDA-ARS?s Scientific Manuscript database

    Traditional and molecular approaches can be used to improve cultivated watermelon (Citrullus lanatus var. lanatus) against whiteflies. The Bemisia tabaci (Hemiptera: Aleyrodidae) whitefly complex attacks many crops on a global scale. It is very adaptive, and it feeds on over 1,000 diverse species of...

  4. Baseline susceptibility of Bemisia tabaci B biotype (Hemiptera: Aleyrodidae) populations from California and Arizona to spiromesifen

    USDA-ARS?s Scientific Manuscript database

    Susceptibility to spiromesifen, a tetronic acid derivative, was determined for three imidacloprid-resistant strains and 12 geographically discrete natural populations of Bemisia tabaci (Gennadius) (= Bemisia argentifolii Bellows and Perring) from California and Arizona by laboratory bioassays. Newl...

  5. Performance of Bemisia tabaci Biotype B on Soybean Genotypes.

    PubMed

    Cruz, P L; Baldin, E L L

    2017-04-01

    Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae) has been recognized as an important pest of many agricultural systems including soybean [Glycine max (L.) Merrill] crops. As an alternative to chemical control, the use of resistant genotypes represents an important tool for integrated pest management (IPM). This study aimed to evaluate the biological development of Bemisia tabaci biotype B confined on 13 soybean genotypes under greenhouse conditions. Initially, the nymphal period, complete development period (egg-adult), and the viability of the silverleaf whitefly nymphs were evaluated in all genotypes. Then, four genotypes promising for resistance ('Jackson,' UX-2569-159, 'P98Y11,' and 'TMG132 RR') and a susceptible genotype (PI-227687) were selected for further assays, where two insect populations were compared: a first population from the initial rearing (cabbage plants) and another corresponding to insects previously reared out on the selected genotypes. In addition to the parameters evaluated in preliminary tests, we also determined the viability and incubation period of eggs. Moderate levels of resistance (antibiosis/antixenosis) to B. tabaci biotype B were found in three genotypes. 'P98Y11' and 'TMG132 RR' were less suitable for insect development, extending the development cycle, and UX-2569-159 caused high nymphal mortality. We did not observe a significant increase in the level of plant resistance by the use of previously stressed insects. This suggests that the evaluation of a single whitefly generation may be sufficient to make correct decisions on promising soybean genotypes.

  6. Comparative susceptibility of bemisia tabaci to imidacloprid in field- and laboratory-based bioassays

    USDA-ARS?s Scientific Manuscript database

    Bemisia tabaci biotype B is a resistance-prone pest of protected and open agriculture. Systemic uptake bioassays used in resistance monitoring programs have provided important information on susceptibility to neonicotinoid insecticides, but have remained decoupled from field performance. Simultaneou...

  7. Monitoring changes in bemisia tabaci susceptibility to neonicotinoid insecticides in Arizona and California

    USDA-ARS?s Scientific Manuscript database

    Laboratory bioassays were carried out on field-collected and laboratory strains of Bemisia tabaci to evaluate relative toxicities of four neonicotinoid insecticides: acetamiprid, dinotefuran, imidacloprid and thiamethoxam. Susceptibility to all four neonicotinoids in leaf-uptake bioassays varied co...

  8. First report of the Q biotype of Bemisia tabaci (Gennadius) in Guatemala

    USDA-ARS?s Scientific Manuscript database

    Bemisia tabaci (Gennadius) adults were collected from poinsettia plants at a commercial greenhouse, bean and zucchini vegetable fields, weed species, and wild ornamentals species in selected locations in Guatemala. Both adult and immature whiteflies were observed on infested poinsettias. Whiteflies ...

  9. Sex affects the infection frequencies of symbionts in Bemisia tabaci

    PubMed Central

    Pan, Huipeng; Li, Xianchun; Zhang, Youjun

    2012-01-01

    While biotype, host plant and geographical location are known to affect the infection dynamics of the six secondary symbionts (S-symbionts) including Hamiltonella, Arsenophonus, Cardinium, Wolbachia, Rickettsia and Fritschea in Bemisia tabaci, it remains unclear whether sex of B. tabaci has an impact on the infection frequencies of the six S-symbionts. To address this issue, gene-specific PCR were conducted to screen for the presence of the six S-symbionts in five host plant-adapted laboratory sub-populations with the same genetic background. Significant variations were exhibited in the infection rates of Rickettsia, Cardinium, Rickettsia + Hamiltonella (RH), Rickettsia + Cardinium (RC), Hamiltonella + Cardinium (HC) and Rickettsia + Hamiltonella + Cardinium (RHC) among the five host plant-adapted sub-populations. Moreover, Rickettsia, Hamiltonella, Cardinium, RH, RC, HC and RHC were present at a significantly higher frequency in the females than in the males of the five host plant-adapted sub-populations. This indicates that sex is another important factor affecting the population dynamics of S-symbionts in B. tabaci. PMID:23060956

  10. Oogenesis in the Bemisia tabaci MEAM1 species complex.

    PubMed

    Guo, Jian-Yang; Wan, Fang-Hao; Ye, Gong-Yin

    2016-04-01

    The whitefly Bemisia tabaci MEAM1 species complex has invaded several parts of the world in the past 30 years and replaced native whitefly populations in the invaded regions, including certain areas of China. One of the possible reasons for the invasion is that MEAM1 whiteflies are more fecund than native species. However, the factors that affect the reproduction of the B. tabaci cryptic species are not clearly known. The regulation of oogenesis is thought to be one of the essential processes for egg formation and ovary development and could affect its population dynamics. In this study, the ovariole structure and oogenesis of the MEAM1 species complex was examined using light and transmission electron microscopy. Telotrophic ovarioles were observed in the MEAM1 species complex. Each ovariole had two well defined regions: the tropharium and the vitellarium. The tropharium always had more than ten trophocytes. The development of a single oocyte in the vitellarium has four phases: oocyte formation, previtellogenesis, vitellogenesis and choriogenesis. Two arrested oocytes, follicular cells and uncompleted oocytes were separated from the tropharium by microtubule and microfilaments. Early previtellogenesis oocytes absorbed nutrients and endosymbiont bacteria through a nutritive cord. However, the vitellogenesis of oocytes transmitted Vg through both the nutritive cord and the space between follicular cells. Each mature oocyte with deposited yolk proteins had only one bacteriocyte and was surrounded by a single layer of follicular cells. The oogenesis in the B. tabaci MEAM1 species complex concluded with the differentiation of oocytes, the transport of yolk and endosymbionts as well as the development and maturation of oocytes. This result provides important information that further defines the regulation of oogenesis in the B. tabaci complex.

  11. Impact of Vapor Pressure Deficit on the Performance of Bemisia tabaci: Adult, Nymphal, and Egg Survival

    USDA-ARS?s Scientific Manuscript database

    The B-biotype sweetpotato whitefly, Bemisia tabaci, is a serious global pest with varying population dynamics among different ecosystems. An experiment was conducted to assess the impact of vapor pressure deficit (VPD) on the survival of adults, nymphs and eggs of B. tabaci. The insects were reared...

  12. Sweet Potato Leaf Curl Virus: Efficiency of Acquisition, Retention and Transmission by Bemisia tabaci (Hemiptera: Aleyrodidae)

    USDA-ARS?s Scientific Manuscript database

    The sweetpotato whitefly, Bemisia tabaci (Gennadius), is a global pest which damages plants directly by feeding on leaves. Moreover, the problem is compounded because B. tabaci also vectors numerous plant viruses, including Begomoviruses (Geminiviridae) such as the Sweet Potato Leaf Curl Virus (SPL...

  13. Protecting Unrooted Cuttings From Bemisia tabaci (Hemiptera Aleyrodidae) During Propagation

    PubMed Central

    Krauter, Peter C.; Arthurs, Steven

    2017-01-01

    Abstract In North America, the sweetpotato whitefly, Bemisia tabaci Genn., is an important pest of greenhouse poinsettia. Growers have limited options to control this pest during propagation of cuttings, which are rooted under mist for several weeks. Early establishment of this pest increases the difficulty of managing the whitefly and retaining high aesthetic standard during the remaining crop production phase. We evaluated two neonicotinoids with translaminar activity, thiamethoxam (Flagship 25WG), and acetamiprid (TriStar 70 WSP), for control of B. tabaci pre-infested on unrooted cuttings propagated under mist. In an experimental greenhouse, both materials significantly reduced whitefly populations, providing an average reduction of 87.8% and 61.5% total recovered whitefly stages respectively, compared with controls. In another test, dipping cuttings in thiamethoxam (immersion treatment) did not improve control significantly, when compared with foliar sprays applied at label rate. In a commercial greenhouse operation, immersion treatments of thiamethoxam on pre-infested poinsettia cuttings maintained whiteflies at ≤ 0.02/plant, compared with up to 0.33/plant in untreated cuttings. Our data suggest that treating unrooted cuttings before or at the start of propagation can be part of an overall strategy for growers to manage whiteflies in poinsettia production.

  14. Implication of Bemisia tabaci heat shock protein 70 in Begomovirus-whitefly interactions.

    PubMed

    Götz, Monika; Popovski, Smadar; Kollenberg, Mario; Gorovits, Rena; Brown, Judith K; Cicero, Joseph M; Czosnek, Henryk; Winter, Stephan; Ghanim, Murad

    2012-12-01

    The whitefly Bemisia tabaci (Gennadius) is a major cosmopolitan pest capable of feeding on hundreds of plant species and transmits several major plant viruses. The most important and widespread viruses vectored by B. tabaci are in the genus Begomovirus, an unusual group of plant viruses owing to their small, single-stranded DNA genome and geminate particle morphology. B. tabaci transmits begomoviruses in a persistent circulative nonpropagative manner. Evidence suggests that the whitefly vector encounters deleterious effects following Tomato yellow leaf curl virus (TYLCV) ingestion and retention. However, little is known about the molecular and cellular basis underlying these coevolved begomovirus-whitefly interactions. To elucidate these interactions, we undertook a study using B. tabaci microarrays to specifically describe the responses of the transcriptomes of whole insects and dissected midguts following TYLCV acquisition and retention. Microarray, real-time PCR, and Western blot analyses indicated that B. tabaci heat shock protein 70 (HSP70) specifically responded to the presence of the monopartite TYLCV and the bipartite Squash leaf curl virus. Immunocapture PCR, protein coimmunoprecipitation, and virus overlay protein binding assays showed in vitro interaction between TYLCV and HSP70. Fluorescence in situ hybridization and immunolocalization showed colocalization of TYLCV and the bipartite Watermelon chlorotic stunt virus virions and HSP70 within midgut epithelial cells. Finally, membrane feeding of whiteflies with anti-HSP70 antibodies and TYLCV virions showed an increase in TYLCV transmission, suggesting an inhibitory role for HSP70 in virus transmission, a role that might be related to protection against begomoviruses while translocating in the whitefly.

  15. Sequence variation of Bemisia tabaci Chemosensory Protein 2 in cryptic species B and Q: New DNA markers for whitefly recognition.

    PubMed

    Liu, Guo-Xia; Ma, Hong-Mei; Xie, Hong-Yan; Xuan, Ning; Picimbon, Jean-François

    2016-01-15

    Bemisia tabaci Gennadius biotypes B and Q are two of the most important worldwide agricultural insect pests. Genomic sequences of Type-2 B. tabaci chemosensory protein (BtabCSP2) were cloned and sequenced in B and Q biotypes, revealing key biotype-specific variations in the intron sequence. A Q260 sequence was found specifically in Q-BtabCSP2 and Cucumis melo LN692399, suggesting ancestral horizontal transfer of gene between the insect and the plant through bacteria. A cleaved amplified polymorphic sequences (CAPS) method was then developed to differentiate B and Q based on the sequence variation in exon of BtabCSP2 gene. The performances of CSP2-based CAPS for whitefly recognition were assessed using B. tabaci field collections from Shandong Province (P.R. China). Our SacII based CAPS method led to the same result compared to mitochondrial cytochrome oxidase-based CAPS method in the field collections. We therefore propose an explanation for CSP origin and a new rapid simple molecular method based on genomic DNA and chemosensory gene to differentiate accurately the B and Q whiteflies of the Bemisia complex around the world.

  16. Developing conversed microsatellite markers and their implications in evolutionary analysis of the Bemisia tabaci complex

    PubMed Central

    Wang, Hua-Ling; Yang, Jiao; Boykin, Laura M.; Zhao, Qiong-Yi; Wang, Yu-Jun; Liu, Shu-Sheng; Wang, Xiao-Wei

    2014-01-01

    The study of population genetics among the Bemisia tabaci complex is limited due to the lack of conserved molecular markers. In this study, 358, 433 and 322 new polynucleotide microsatellites are separately identified from the transcriptome sequences of three cryptic species of the B. tabaci complex. The cross species transferability of 57 microsatellites was then experimentally validated. The results indicate that these markers are conserved and have high inter-taxon transferability. Thirteen markers were employed to assess the genetic relationships among six cryptic species of the B. tabaci complex. To our surprise, the inferred phylogeny was consistent with that of mitochondrial COI sequences, indicating that microsatellites have the potential to distinguish species of the B. tabaci complex. Our results demonstrate that development of microsatellites from transcriptome data is a fast and cost-effective approach. These markers can be used to analyze the population genetics and evolutionary patterns of the B. tabaci complex. PMID:25220501

  17. Natural enemy impacts on bemisia tabaci dominate plant quality effects in the cotton system

    USDA-ARS?s Scientific Manuscript database

    Plant quality (bottom-up effects) and natural enemies (top-down effects) affect herbivore performance and population dynamics; plant quality can influence the impact of natural enemies. Lower plant quality through reduced irrigation generally increases the abundance of Bemisia tabaci Gennadius (Aley...

  18. Extraordinary resistance to insecticides reveals exotic Q biotype of Bemisia tabaci (Gennadius) in the New World

    USDA-ARS?s Scientific Manuscript database

    The whitefly Bemisia tabaci (Gennadius) possessing unusually high levels of resistance to a wide range of insecticides were discovered in 2004 in the course of routine resistance monitoring in Arizona. The multiply-resistant insects, collected from poinsettia (Euphorbia pulcherrima) plants purchased...

  19. Aerial electrostatic-charged spray for deposition and efficacy against sweetpotato whitefly (Bemisia tabaci) on cotton

    USDA-ARS?s Scientific Manuscript database

    Efficacy of aerial electrostatic-charged sprays was evaluated for spray deposit characteristics and season-long control of sweet potato whitefly (SWF), Bemisia tabaci biotype B (a.k.a. B. argentifolii), in an irrigated 24-ha cotton field. Treatments included electrostatic-charged sprays at full and ...

  20. Extraordinary resistance to insecticides reveals exotic Q biotype of Bemisia tabaci

    USDA-ARS?s Scientific Manuscript database

    The whitefly Bemisia tabaci (Gennadius) possessing unusually high levels of resistance to a wide range of insecticides were discovered in 2004 in the course of routine resistance monitoring in Arizona. The multiply-resistant insects, collected from poinsettia (Euphorbia pulcherrima) plants purchased...

  1. Insecticidal Activity of Some Reducing Sugars Against the Sweet Potato Whitefly, Bemisia tabaci, Biotype B

    USDA-ARS?s Scientific Manuscript database

    The effects of 15 sugars on sweet potato whitefly (Bemisia tabaci) survival were determined using bioassays. Arabinose, mannose, ribose and xylose were strongly inhibitory to both nymphal and adult survival. When 10% mannose was added to the diet, 10.5%, 1.0% and 0% of nymphs developed to the 2nd, ...

  2. Insecticidal Activity of Chromobacterium subtsugae on the Sweet Potato Whitefly, Bemisia tabaci, Biotype B

    USDA-ARS?s Scientific Manuscript database

    Chromobacterium subtsugae crude extracts contain compounds that are toxic to nymphal and adult Bemisia tabaci. When fed on artificial diet containing 10% of the supernatant of an aqueous cell-free extract of C subtsugae, the number of 2nd and 4th instar nymphs and of emerged adults was significantl...

  3. Mortality and Population Dynamics of Bemisia tabaci within a Multi-Crop System

    USDA-ARS?s Scientific Manuscript database

    The population dynamics of mobile polyphagous pests is governed by a complex set of interacting factors that involve multiple host-plants, seasonality, movement and demography. Bemisia tabaci is a multivoltine insect with no diapause that maintains population continuity by moving from one host to a...

  4. Population genetics of invasive Bemisia tabaci cryptic species in the United States based on microsatellite markers

    USDA-ARS?s Scientific Manuscript database

    The Bemisia tabaci cryptic species complex of whiteflies contains two species, MEAM1 and MED, that are highly invasive in supportive climates the world over. In the United States MEAM1 occurs both in the field and in the greenhouse, but MED is only found in the greenhouse. In order to make inference...

  5. Population genetics of invasive Bemisia tabaci cryptic species in the United States based on microsatellite markers

    USDA-ARS?s Scientific Manuscript database

    The Bemisia tabaci cryptic species complex of whiteflies contains two species, MEAM1 and MED, that are highly invasive in supportive climates the world over. In the U.S. MEAM1 occurs both in the field and in the greenhouse but MED is only found in the greenhouse. In order to make inferences about th...

  6. Effect of soil application of cyantraniliprole on Bemisia tabaci (MED whitefly) and Amblyseius swirskii, 2016

    USDA-ARS?s Scientific Manuscript database

    Bemisia tabaci is a polyphagous pest known to feed upon over 900 plant taxa, and is an effective vector of more than 100 plant damaging viruses. Among different biotypes of this cryptic species complex, MEAM1 and MED whitefly are the two most destructive members posing threats of several crops of ec...

  7. Effect of dinotefuran on Bemisia tabaci (MED whitefly) and Amblyseius swirskii, 2016

    USDA-ARS?s Scientific Manuscript database

    Bemisia tabaci is a polyphagous pest known to feed upon over 900 plant taxa, and is an effective vector of more than 100 plant damaging viruses. Among different biotypes of this cryptic species complex, MEAM1 and MED whitefly are the two most destructive members posing threats of several crops of ec...

  8. Effect of Eretmocerus eremicus and soil application of cyantraniliprole on Bemisia tabaci (MED whitefly), 2016

    USDA-ARS?s Scientific Manuscript database

    Bemisia tabaci is a polyphagous pest known to feed on over 900 plant taxa, and is an effective vector of more than 100 plant damaging viruses. Among different biotypes of this cryptic species complex, MEAM1 and MED whitefly are the two most destructive members posing threats to several crops of econ...

  9. Impact of drench application of cyantraniliprole on Bemisia tabaci (MED whitefly) and Amblyseius swirskii, 2016

    USDA-ARS?s Scientific Manuscript database

    Bemisia tabaci is a polyphagous pest known to feed on over 900 plant taxa, and is an effective vector of more than 100 plant damaging viruses. Among different biotypes of this cryptic species complex, MEAM1 and MED whitefly are the two most destructive members posing threats of several crops of econ...

  10. Effect of foliar application of pymetrozine on Bemisia tabaci (MED whitefly) and Amblyseius swirskii, 2016

    USDA-ARS?s Scientific Manuscript database

    Bemisia tabaci is a polyphagous pest known to feed upon over 900 plant taxa, and is an effective vector of more than 100 plant damaging viruses. Among different biotypes of this cryptic species complex, MEAM1 and MED whitefly are the two most destructive members posing threats of several crops of ec...

  11. Efficacy of Eretmocerus eremicus and cyantraniliprole on Bemisia tabaci (MED whitefly), 2017

    USDA-ARS?s Scientific Manuscript database

    Bemisia tabaci (Gennadius) feeds on more than 900 host plants and vectors over 111 plant virus species and is considered to be a major invasive species worldwide. Among different biotypes of this cryptic species complex, MEAM1 and MED whitefly are the two most destructive members posing threats to s...

  12. Host plant influences on susceptibility of bemisia tabaci (Hemiptera: Aleyrodidae) to insecticides

    USDA-ARS?s Scientific Manuscript database

    : A resistance monitoring program conducted for the polyphagous whitefly Bemisia tabaci (Gennadius) in Imperial Valley, CA, USA generated a large set of LC50s for adults collected from broccoli, cantaloupe and cotton crops over a four-year period. A vial bioassay and subsequently a yellow-sticky ca...

  13. Molecular and functional characterization of Bemisia tabaci aquaporins reveals the water channel diversity of hemipteran insects

    USDA-ARS?s Scientific Manuscript database

    The Middle East-Asia Minor 1 (MEAM1) whitefly, Bemisia tabaci (Gennadius) is an economically important pest of food, fiber, and ornamental crops. This pest has evolved a number of adaptations to overcome physiological challenges, including 1) the ability to regulate osmotic stress between gut lumen ...

  14. Identification and characterization of functional aquaporin water channel protein from alimentary tract of whitefly, Bemisia tabaci

    USDA-ARS?s Scientific Manuscript database

    Some hemipteran xylem and phloem feeding insects have evolved specialized alimentary structures or filter chambers that rapidly transport water for excretion or osmoregulation. In the whitefly, Bemisia tabaci, mass movement of water through opposing alimentary tract tissues within the filter chamber...

  15. Releases of exotic parasitoids of Bemisia tabaci in San Joaquin Valley, California

    USDA-ARS?s Scientific Manuscript database

    In 1991, Bemisia tabaci was reported in the southern San Joaquin Valley infesting crops outside of greenhouses for the first time. From 1994 to 1996, 24 species/ strains of imported aphelinids, primarily species of Eretmocerus, were released in urban and agricultural settings for control of this whi...

  16. Climate change and Bemisia tabaci (Hemiptera: Aleyrodidae): Impacts of temperature and carbon dioxide on life history

    USDA-ARS?s Scientific Manuscript database

    Climate change is relevant to life around the globe. A rise in ambient temperature and CO2 may have various impacts on arthropods such as altered life cycles, modified reproductive patterns, and changes in distribution. The sweetpotato whitefly, Bemisia tabaci (Gennadius), is a global agricultural...

  17. Molecular Characterization of Vitellogenin and Vitellogenin Receptor of Bemisia tabaci

    PubMed Central

    Upadhyay, Santosh Kumar; Singh, Harpal; Dixit, Sameer; Mendu, Venugopal; Verma, Praveen C.

    2016-01-01

    Vitellogenin (Vg) plays vital role in oocytes and embryo development in insects. Vg is synthesized in the fat body, moves through haemolymph and accumulates in oocytes. Vitellogenin receptors (VgR) present on the surface of oocytes, are responsible for Vg transportation from haemolymph to oocytes. Here, we cloned and characterized these genes from Bemisia tabaci Asia1 (BtA1) species. The cloned BtA1Vg and BtA1VgR genes consisted of 6,330 and 5,430 bp long open reading frames, which encoded 2,109 and 1,809 amino acid (AA) residues long protein. The BtA1Vg protein comprised LPD_N, DUF1943 and VWFD domains, typical R/KXXR/K, DGXR and GL/ICG motifs, and polyserine tracts. BtA1VgR protein contained 12 LDLa, 10 LDLb and 7 EGF domains, and a trans-membrane and cytoplasmic region at C-terminus. Phylogenetic analyses indicated evolutionary association of BtA1Vg and BtA1VgR with the homologous proteins from various insect species. Silencing of BtA1VgR by siRNA did not affect the transcript level of BtA1Vg. However, BtA1Vg protein accumulation in oocytes was directly influenced with the expression level of BtA1VgR. Further, BtA1VgR silencing caused significant mortality and reduced fecundity in adult whiteflies. The results established the role of BtA1VgR in transportation of BtA1Vg in oocytes. Further, these proteins are essential for fecundity, and therefore these can be potential RNAi targets for insect control in crop plants. PMID:27159161

  18. Compatibility of the insect pathogenic fungus Beauveria bassiana with neem against sweetpotato whitefly, Bemisia tabaci, on eggplant

    USDA-ARS?s Scientific Manuscript database

    A study on the compatibility of the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin (Ascomycota: Hypocreales) with neem was conducted against sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), on eggplant. Initially, three concentrations of B. bassiana (106, 1...

  19. Evidence of diversity and recombination in Arsenophonus symbionts of the Bemisia tabaci species complex

    PubMed Central

    2012-01-01

    Background Maternally inherited bacterial symbionts infecting arthropods have major implications on host ecology and evolution. Among them, the genus Arsenophonus is particularly characterized by a large host spectrum and a wide range of symbiotic relationships (from mutualism to parasitism), making it a good model to study the evolution of host-symbiont associations. However, few data are available on the diversity and distribution of Arsenophonus within host lineages. Here, we propose a survey on Arsenophonus diversity in whitefly species (Hemiptera), in particular the Bemisia tabaci species complex. This polyphagous insect pest is composed of genetic groups that differ in many ecological aspects. They harbor specific bacterial communities, among them several lineages of Arsenophonus, enabling a study of the evolutionary history of these bacteria at a fine host taxonomic level, in association to host geographical range and ecology. Results Among 152 individuals, our analysis identified 19 allelic profiles and 6 phylogenetic groups, demonstrating this bacterium's high diversity. These groups, based on Arsenophonus phylogeny, correlated with B. tabaci genetic groups with two exceptions reflecting horizontal transfers. None of three genes analyzed provided evidence of intragenic recombination, but intergenic recombination events were detected. A mutation inducing a STOP codon on one gene in a strain infecting one B. tabaci genetic group was also found. Phylogenetic analyses of the three concatenated loci revealed the existence of two clades of Arsenophonus. One, composed of strains found in other Hemiptera, could be the ancestral clade in whiteflies. The other, which regroups strains found in Hymenoptera and Diptera, may have been acquired more recently by whiteflies through lateral transfers. Conclusions This analysis of the genus Arsenophonus revealed a diversity within the B. tabaci species complex which resembles that reported on the larger scale of insect

  20. Prey Preference and Life Table of Amblyseius orientalis on Bemisia tabaci and Tetranychus cinnabarinus

    PubMed Central

    Hu, Yue; Wang, Boming; Chen, Xi; Xu, Xuenong; Wang, Endong

    2015-01-01

    Amblyseius orientalis (Ehara) (Acari: Phytoseiidae) is a native predatory mite species in China. It used to be considered as a specialist predator of spider mites. However, recent studies show it also preys on other small arthropod pests, such as Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). Experiments were conducted to investigate (1) prey preference of A. orientalis between Tetranychus cinnabarinus (Boisd.) (Acari: Tetranychidae) and B. tabaci, and (2) development, consumption and life table parameters of A. orientalis when reared on T. cinnabarinus, B. tabaci or a mix of both prey species. When preying on different stages of T. cinnabarinus, A. orientalis preferred protonymphs, whereas when preying on different stages of B. tabaci, A. orientalis preferred eggs. When these two most preferred stages were provided together (T. cinnabarinus protonymphs and B. tabaci eggs), A. orientalis randomly selected its prey. Amblyseius orientalis was able to complete its life cycle on B. tabaci eggs, T. cinnabarinus protonymphs, or a mix of both prey. However, its developmental duration was 53.9% and 30.0% longer when reared on B. tabaci eggs than on T. cinnabarinus and a mix of both prey, respectively. In addition, it produced only a few eggs and its intrinsic rate of increase was negative when reared on B. tabaci eggs, which indicates that B. tabaci is not sufficient to maintain A. orientalis population. The intrinsic rates of increase were 0.16 and 0.23 when A. orientalis was fed on the prey mix and T. cinnabarinus, respectively. These results suggest that although B. tabaci is a poor food resource for A. orientalis in comparison to T. cinnabarinus, A. orientalis is able to sustain its population on a mix of both prey. This predatory mite may thus be a potential biological control agent of B. tabaci when this pest co-occurs with the alternative minor pest T. cinnabarinus. PMID:26436422

  1. Interspecific interactions between Bemisia tabaci biotype B and Trialeurodes vaporariorum (Hemiptera: Aleyrodidae).

    PubMed

    Zhang, Gui-Fen; Li, Dong-Chao; Liu, Tong-Xian; Wan, Fang-Hao; Wang, Jin-Jun

    2011-02-01

    Bemisia tabaci (Gennadius) biotype B and Trialeurodes vaporariorum (Westwood) are invasive whitefly species that often co-occur on greenhouse-grown vegetables in northern China. Although B. tabaci biotype B has been present in China for a relatively short period of time, it has become dominant over T. vaporariorum. We studied the interspecific competitive interactions between the two species in single or mixed cultures at 24 ± 1 °C, 40 ± 5% RH, and L14:D10 h photoperiod. Female longevity on tomato was not significantly different between species, but B. tabaci reproduced 4.3 to 4.9 fold more progeny. The ratio of female to male progeny in both instances was greater for B. tabaci. When cultured on tomato, cotton, and tobacco, B. tabaci developed 0.8, 3.3, and 4.7 d earlier in single culture, and 1.8, 3.9, and 4.3 d earlier in mixed culture. B. tabaci displaced T. vaporariorum in four, five and six generations when the initial ratios of B. tabaci to T. vaporariorum were 15:15, 20:10, or 10:20 on tomato. Populations of B. tabaci were 2.3 fold higher than that of T. vaporariorum on tomato plants for seven consecutive generations in single culture. B. tabaci performed better in development, survival, fecundity, and female ratio. We conclude that B. tabaci could displace T. vaporariorum in as short as four generations in a controlled greenhouse environment when they start at equal proportions. Warmer greenhouse conditions and an increase in total greenhouse area could be contributing factors in the recent dominance of B. tabaci. © 2011 Entomological Society of America

  2. RNA Interference based Approach to Down Regulate Osmoregulators of Whitefly (Bemisia tabaci): Potential Technology for the Control of Whitefly.

    PubMed

    Raza, Amir; Malik, Hassan Jamil; Shafiq, Muhammad; Amin, Imran; Scheffler, Jodi A; Scheffler, Brian E; Mansoor, Shahid

    2016-01-01

    Over the past decade RNA interference (RNAi) technology has emerged as a successful tool not only for functional genomics, but in planta expression of short interfering RNAs (siRNAs) that could offer great potential for insect pest management. The diet of insects feeding exclusively on phloem sieves contains water and sugars as main components, and the uptake of the liquid food greatly depends on the osmotic pressure within the insect body. Based on this physiological mechanism, transgenic plants of Nicotiana tabacum were generated expressing double stranded RNA (dsRNA) against both aquaporin (AQP) and a sucrase gene, alpha glucosidase (AGLU). These two genes are involved in osmotic pressure maintenance particularly in sap sucking insects, and the aim was to disrupt osmoregulation within the insect ultimately leading to mortality. Real time quantitative PCR (RT-qPCR) was performed to assess the suppression of gene expression in Bemisia tabaci (B. tabaci) and mortality was recorded during transgenic tobacco feeding bioassays. Feeding of insects on plants expressing dsRNA significantly reduced the transcript level of the target genes in B. tabaci after six days of feeding and more than 70% mortality was observed in B. tabaci fed on transgenic plants compared to the control plants. Our data shows that down-regulation of genes related to osmoregulation may find practical applications for the control of this important pest in cotton and other crops.

  3. RNA Interference based Approach to Down Regulate Osmoregulators of Whitefly (Bemisia tabaci): Potential Technology for the Control of Whitefly

    PubMed Central

    Raza, Amir; Malik, Hassan Jamil; Shafiq, Muhammad; Amin, Imran; Scheffler, Jodi A.; Scheffler, Brian E.; Mansoor, Shahid

    2016-01-01

    Over the past decade RNA interference (RNAi) technology has emerged as a successful tool not only for functional genomics, but in planta expression of short interfering RNAs (siRNAs) that could offer great potential for insect pest management. The diet of insects feeding exclusively on phloem sieves contains water and sugars as main components, and the uptake of the liquid food greatly depends on the osmotic pressure within the insect body. Based on this physiological mechanism, transgenic plants of Nicotiana tabacum were generated expressing double stranded RNA (dsRNA) against both aquaporin (AQP) and a sucrase gene, alpha glucosidase (AGLU). These two genes are involved in osmotic pressure maintenance particularly in sap sucking insects, and the aim was to disrupt osmoregulation within the insect ultimately leading to mortality. Real time quantitative PCR (RT-qPCR) was performed to assess the suppression of gene expression in Bemisia tabaci (B. tabaci) and mortality was recorded during transgenic tobacco feeding bioassays. Feeding of insects on plants expressing dsRNA significantly reduced the transcript level of the target genes in B. tabaci after six days of feeding and more than 70% mortality was observed in B. tabaci fed on transgenic plants compared to the control plants. Our data shows that down-regulation of genes related to osmoregulation may find practical applications for the control of this important pest in cotton and other crops. PMID:27105353

  4. Compatibility of the entomopathogenic fungus Lecanicillium muscarium and insecticides for eradication of sweetpotato whitefly, Bemisia tabaci.

    PubMed

    Cuthbertson, Andrew G S; Walters, Keith F A; Deppe, Carola

    2005-08-01

    The compatibility of the entomopathogenic fungus Lecanicillium muscarium and chemical insecticides used to control the second instar stages of the sweetpotato whitefly, Bemisia tabaci, was investigated. The effect on spore germination of direct exposure for 24 h to the insecticides imidacloprid, buprofezin, teflubenzuron and nicotine was determined. Only exposure to buprofezin was followed by acceptable spore germination. However, all chemicals significantly reduced spore germination when compared to a water control. Infectivity of L. muscarium in the presence of dry residues of buprofezin, teflubenzuron and nicotine (imidacloprid is a systemic pesticide) on foliage were also investigated. No significant detrimental effects on the level of control of B. tabaci was recorded when compared with fungi applied to residue free foliage on either tomato or verbena plants. Fungi in combination with imidacloprid gave higher B. tabaci mortality on verbena foliage compared to either teflubenzuron or nicotine and fungi combinations. Use of these chemical insecticides with L. muscarium in integrated control programmes for B. tabaci is discussed.

  5. Tomato yellow leaf curl virus: No evidence for replication in the insect vector Bemisia tabaci

    PubMed Central

    Sánchez-Campos, Sonia; Rodríguez-Negrete, Edgar A.; Cruzado, Lucía; Grande-Pérez, Ana; Bejarano, Eduardo R.; Navas-Castillo, Jesús; Moriones, Enrique

    2016-01-01

    Begomovirus ssDNA plant virus (family Geminiviridae) replication within the Bemisia tabaci vector is controversial. Transovarial transmission, alteration to whitefly biology, or detection of viral transcripts in the vector are proposed as indirect evidence of replication of tomato yellow leaf curl virus (TYLCV). Recently, contrasting direct evidence has been reported regarding the capacity of TYLCV to replicate within individuals of B. tabaci based on quantitave PCR approaches. Time-course experiments to quantify complementary and virion sense viral nucleic acid accumulation within B. tabaci using a recently implemented two step qPCR procedure revealed that viral DNA quantities did not increase for time points up to 96 hours after acquisition of the virus. Our findings do not support a recent report claiming TYLCV replication in individuals of B. tabaci. PMID:27476582

  6. Indigenous American species of the Bemisia tabaci complex are still widespread in the Americas.

    PubMed

    Barbosa, Leonardo da F; Marubayashi, Julio M; De Marchi, Bruno R; Yuki, Valdir A; Pavan, Marcelo A; Moriones, Enrique; Navas-Castillo, Jesús; Krause-Sakate, Renate

    2014-10-01

    Bemisia tabaci is a complex of at least 36 putative cryptic species. Since the late 1980s, the Middle East-Asia Minor 1 species (MEAM1, formerly known as the B biotype), has emerged in many tropical and subtropical regions of the world and in some areas has displaced the indigenous populations of B. tabaci. Based on analysis of the mtCOI gene, two indigenous species native to America have been reported: New World (NW, formerly the A biotype) and New World 2 (NW2). NW is present at least in Argentina, Brazil, Martinique, Mexico, Texas and Venezuela, and NW2 in Argentina, Bolivia and Brazil. Wild plants (Euphorbia sp. and Ipomoea sp.), as well as important crops such as tomato, bean and cotton, are still hosts for native B. tabaci populations in the Americas. MEAM1 has not completely displaced the native B. tabaci from the Americas.

  7. Phylogenetic analysis and inflow route of Tomato yellow leaf curl virus (TYLCV) and Bemisia tabaci in Korea.

    PubMed

    Lee, Hyejung; Song, Woogeun; Kwak, Hae-Ryun; Kim, Jae-Deok; Park, Jungan; Auh, Chung-Kyoon; Kim, Dae-Hyun; Lee, Kyeong-Yeoll; Lee, Sukchan; Choi, Hong-Soo

    2010-11-01

    Tomato yellow leaf curl virus (TYLCV) is a member of the genus Begomovirus of the family Geminiviridae, members of which are characterized by closed circular single-stranded DNA genomes of 2.7-2.8 kb in length, and include viruses transmitted by the Bemisia tabaci whitefly. No reports of TYLCV in Korea are available prior to 2008, after which TYLCV spread rapidly to most regions of the southern Korean peninsula (Gyeongsang-Do, Jeolla-Do and Jeju-Do). Fifty full sequences of TYLCV were analyzed in this study, and the AC1, AV1, IR, and full sequences were analyzed via the muscle program and bayesian analysis. Phylogenetic analysis demonstrated that the Korea TYLCVs were divided into two subgroups. The TYLCV Korea 1 group (Masan) originated from TYLCV Japan (Miyazaki) and the TYLCV Korea 2 group (Jeju/Jeonju) from TYLCV Japan (Tosa/Haruno). A B. tabaci phylogenetic tree was constructed with 16S rRNA and mitochondria cytochrome oxidase I (MtCOI) sequences using the muscle program and MEGA 4.0 in the neighbor-joining algorithm. The sequence data of 16S rRNA revealed that Korea B. tabaci was closely aligned to B. tabaci isolated in Iran and Nigeria. The Q type of B. tabaci, which was originally identified as a viruliferous insect in 2008, was initially isolated in Korea as a non-viruliferous insect in 2005. Therefore, we suggest that two TYLCV Japan isolates were introduced to Korea via different routes, and then transmitted by native B. tabaci.

  8. Feeding Experience of Bemisia tabaci (Hemiptera: Aleyrodidae) Affects Their Performance on Different Host Plants

    PubMed Central

    Shah, M. Mostafizur Rahman; Liu, Tong-Xian

    2013-01-01

    The sweetpotato whitefly, Bemisia tabaci biotype B is extremely polyphagous with >600 species of host plants. We hypothesized that previous experience of the whitefly on a given host plant affects their host selection and performance on the plants without previous experience. We investigated the host selection for feeding and oviposition of adults and development and survival of immatures of three host-plant-experienced populations of B. tabaci, namely Bemisia-eggplant, Bemisia-tomato and Bemisia-cucumber, on their experienced host plant and each of the three other plant species (eggplant, tomato, cucumber and pepper) without previous experience. We found that the influence of previous experience of the whiteflies varied among the populations. All populations refused pepper for feeding and oviposition, whereas the Bemisia-cucumber and the Bemisia-eggplant strongly preferred cucumber. Bemisia-tomato did not show strong preference to any of the three host palnts. Development time from egg to adult eclosion varied among the populations, being shortest on eggplant, longest on pepper, and intermediate on tomato and cucumber except for the Bemisia-cucumber developed similarly on tomato and pepper. The survivorship from egg to adult eclosion of all populations was highest on eggplant (80-98%), lowest on pepper (0-20%), and intermediate on tomato and cucumber. In conclusion, the effects of previous experience of whiteflies on host selection for feeding and oviposition, development, and survivorship varied depending on host plants, and host plants play a stronger role than previous experience. Preference of feeding and oviposition by adults may not accurately reflect host suitability of immatures. These results provided important information for understanding whitefly population dynamics and dispersal among different crop systems. PMID:24146985

  9. Baseline susceptibility of Bemisia tabaci B biotype (Hemiptera:Aleyrodidae) populations from Californis and Arizona to spirotetramat

    USDA-ARS?s Scientific Manuscript database

    Baseline toxicity levels to foliarly applied spirotetramat were established for 19 field populations of whiteflies, Bemisia tabaci B biotype from Arizona and California in 2008 and 2009. The susceptibility data was determined against the 2nd instar of B. tabaci field collections before the registrat...

  10. Genetic distinctions among the Mediterranean and Chinese populations of Bemisia tabaci Q biotype and their endosymbiont Wolbachia populations

    USDA-ARS?s Scientific Manuscript database

    The sweetpotato whitefly, Bemisia tabaci, is a cryptic species complex composed of more than 24 different biotypes around the world. The Q biotype of B. tabaci, which is thought to have originated in the Mediterranean Basin, is now a widespread and serious agricultural pest. In this study, the genet...

  11. Pyrosequencing the Bemisia tabaci Transcriptome Reveals a Highly Diverse Bacterial Community and a Robust System for Insecticide Resistance

    PubMed Central

    Wu, Qing-jun; Wang, Shao-li; Yang, Xin; Yang, Ni-na; Li, Ru-mei; Jiao, Xiao-guo; Pan, Hui-peng; Liu, Bai-ming; Su, Qi; Xu, Bao-yun; Hu, Song-nian; Zhou, Xu-guo; Zhang, You-jun

    2012-01-01

    Background Bemisia tabaci (Gennadius) is a phloem-feeding insect poised to become one of the major insect pests in open field and greenhouse production systems throughout the world. The high level of resistance to insecticides is a main factor that hinders continued use of insecticides for suppression of B. tabaci. Despite its prevalence, little is known about B. tabaci at the genome level. To fill this gap, an invasive B. tabaci B biotype was subjected to pyrosequencing-based transcriptome analysis to identify genes and gene networks putatively involved in various physiological and toxicological processes. Methodology and Principal Findings Using Roche 454 pyrosequencing, 857,205 reads containing approximately 340 megabases were obtained from the B. tabaci transcriptome. De novo assembly generated 178,669 unigenes including 30,980 from insects, 17,881 from bacteria, and 129,808 from the nohit. A total of 50,835 (28.45%) unigenes showed similarity to the non-redundant database in GenBank with a cut-off E-value of 10–5. Among them, 40,611 unigenes were assigned to one or more GO terms and 6,917 unigenes were assigned to 288 known pathways. De novo metatranscriptome analysis revealed highly diverse bacterial symbionts in B. tabaci, and demonstrated the host-symbiont cooperation in amino acid production. In-depth transcriptome analysis indentified putative molecular markers, and genes potentially involved in insecticide resistance and nutrient digestion. The utility of this transcriptome was validated by a thiamethoxam resistance study, in which annotated cytochrome P450 genes were significantly overexpressed in the resistant B. tabaci in comparison to its susceptible counterparts. Conclusions This transcriptome/metatranscriptome analysis sheds light on the molecular understanding of symbiosis and insecticide resistance in an agriculturally important phloem-feeding insect pest, and lays the foundation for future functional genomics research of the B. tabaci complex

  12. Insecticide resistance in field populations of Bemisia tabaci (Hemiptera: Aleyrodidae) in West Africa.

    PubMed

    Houndété, Thomas A; Kétoh, Guillaume K; Hema, Omer S A; Brévault, Thierry; Glitho, Isabelle A; Martin, Thibaud

    2010-11-01

    The tobacco whitefly, Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae), has developed a high degree of resistance to several chemical classes of insecticides throughout the world. To evaluate the resistance status in West Africa, eight insecticides from different chemical families were tested using the leaf-dip method on four field populations collected from cotton in Benin, Togo and Burkina Faso. Some field populations showed a significant loss of susceptibility to pyrethroids such as deltamethrin [resistance ratio (RR) 3-5] and bifenthrin (RR 4-36), to organophosphates (OPs) such as dimethoate (RR 8-15) and chlorpyrifos (RR 5-7) and to neonicotinoids such as acetamiprid (RR 7-8) and thiamethoxam (RR 3-7). Bemisia tabaci was also resistant to pymetrozine (RR 3-18) and to endosulfan (RR 14-30). The resistance of B. tabaci to pyrethroids and OPs is certainly due to their systematic use in cotton treatments for more than 30 years. Acetamiprid has been recently introduced for the control of whiteflies. Unfortunately, B. tabaci populations from Burkina Faso seem to be already resistant. Because cross-resistance between these compounds has never been observed elsewhere, resistance to neonicotinoids could be due to the presence of an invasive B. tabaci biotype recently detected in the region. Copyright © 2010 Society of Chemical Industry.

  13. Characterization of a newly discovered symbiont of the whitefly Bemisia tabaci (Hemiptera: Aleyrodidae).

    PubMed

    Bing, Xiao-Li; Yang, Jiao; Zchori-Fein, Einat; Wang, Xiao-Wei; Liu, Shu-Sheng

    2013-01-01

    Bemisia tabaci (Hemiptera: Aleyrodidae) is a species complex containing >28 cryptic species, some of which are important crop pests worldwide. Like many other sap-sucking insects, whiteflies harbor an obligatory symbiont, "Candidatus Portiera aleyrodidarum," and a number of secondary symbionts. So far, six genera of secondary symbionts have been identified in B. tabaci. In this study, we report and describe the finding of an additional bacterium in the indigenous B. tabaci cryptic species China 1 (formerly known as B. tabaci biotype ZHJ3). Phylogenetic analysis based on the 16S rRNA and gltA genes showed that the bacterium belongs to the Alphaproteobacteria subdivision of the Proteobacteria and has a close relationship with human pathogens of the genus Orientia. Consequently, we temporarily named it Orientia-like organism (OLO). OLO was found in six of eight wild populations of B. tabaci China 1, with the infection rate ranging from 46.2% to 76.8%. Fluorescence in situ hybridization (FISH) of B. tabaci China 1 in nymphs and adults revealed that OLOs are confined to the bacteriome and co-occur with "Ca. Portiera aleyrodidarum." The vertical transmission of OLO was demonstrated by detection of OLO at the anterior pole end of the oocytes through FISH. Quantitative PCR analysis of population dynamics suggested a complex interaction between "Ca. Portiera aleyrodidarum" and OLO. Based on these results, we propose "Candidatus Hemipteriphilus asiaticus" for the classification of this symbiont from B. tabaci.

  14. Update on the Status of Bemisia tabaci in the UK and the Use of Entomopathogenic Fungi within Eradication Programmes

    PubMed Central

    Cuthbertson, Andrew G. S.

    2013-01-01

    The sweetpotato whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) continues to be a serious threat to crops worldwide. The UK holds Protected Zone status against this pest and, as a result, B. tabaci entering on plant material is subjected to a policy of eradication. Both B and Q Bemisia biotypes are now regularly intercepted entering the UK. With increasing reports of neonicotinoid resistance in both these biotypes, it is becoming more problematic to control/eradicate. Therefore, alternative means of control are necessary. Entomopathogenic fungi (Lecanicilllium muscarium and Beauveria bassiana) offer much potential as control agents of B. tabaci within eradication programmes in the UK. PMID:26464385

  15. Biotype Characterization, Developmental Profiling, Insecticide Response and Binding Property of Bemisia tabaci Chemosensory Proteins: Role of CSP in Insect Defense.

    PubMed

    Liu, Guoxia; Ma, Hongmei; Xie, Hongyan; Xuan, Ning; Guo, Xia; Fan, Zhongxue; Rajashekar, Balaji; Arnaud, Philippe; Offmann, Bernard; Picimbon, Jean-François

    2016-01-01

    Chemosensory proteins (CSPs) are believed to play a key role in the chemosensory process in insects. Sequencing genomic DNA and RNA encoding CSP1, CSP2 and CSP3 in the sweet potato whitefly Bemisia tabaci showed strong variation between B and Q biotypes. Analyzing CSP-RNA levels showed not only biotype, but also age and developmental stage-specific expression. Interestingly, applying neonicotinoid thiamethoxam insecticide using twenty-five different dose/time treatments in B and Q young adults showed that Bemisia CSP1, CSP2 and CSP3 were also differentially regulated over insecticide exposure. In our study one of the adult-specific gene (CSP1) was shown to be significantly up-regulated by the insecticide in Q, the most highly resistant form of B. tabaci. Correlatively, competitive binding assays using tryptophan fluorescence spectroscopy and molecular docking demonstrated that CSP1 protein preferentially bound to linoleic acid, while CSP2 and CSP3 proteins rather associated to another completely different type of chemical, i.e. α-pentyl-cinnamaldehyde (jasminaldehyde). This might indicate that some CSPs in whiteflies are crucial to facilitate the transport of fatty acids thus regulating some metabolic pathways of the insect immune response, while some others are tuned to much more volatile chemicals known not only for their pleasant odor scent, but also for their potent toxic insecticide activity.

  16. Biotype Characterization, Developmental Profiling, Insecticide Response and Binding Property of Bemisia tabaci Chemosensory Proteins: Role of CSP in Insect Defense

    PubMed Central

    Liu, Guoxia; Ma, Hongmei; Xie, Hongyan; Xuan, Ning; Guo, Xia; Fan, Zhongxue; Rajashekar, Balaji; Arnaud, Philippe; Offmann, Bernard; Picimbon, Jean-François

    2016-01-01

    Chemosensory proteins (CSPs) are believed to play a key role in the chemosensory process in insects. Sequencing genomic DNA and RNA encoding CSP1, CSP2 and CSP3 in the sweet potato whitefly Bemisia tabaci showed strong variation between B and Q biotypes. Analyzing CSP-RNA levels showed not only biotype, but also age and developmental stage-specific expression. Interestingly, applying neonicotinoid thiamethoxam insecticide using twenty-five different dose/time treatments in B and Q young adults showed that Bemisia CSP1, CSP2 and CSP3 were also differentially regulated over insecticide exposure. In our study one of the adult-specific gene (CSP1) was shown to be significantly up-regulated by the insecticide in Q, the most highly resistant form of B. tabaci. Correlatively, competitive binding assays using tryptophan fluorescence spectroscopy and molecular docking demonstrated that CSP1 protein preferentially bound to linoleic acid, while CSP2 and CSP3 proteins rather associated to another completely different type of chemical, i.e. α-pentyl-cinnamaldehyde (jasminaldehyde). This might indicate that some CSPs in whiteflies are crucial to facilitate the transport of fatty acids thus regulating some metabolic pathways of the insect immune response, while some others are tuned to much more volatile chemicals known not only for their pleasant odor scent, but also for their potent toxic insecticide activity. PMID:27167733

  17. Bemisia tabaci MED (Q biotype) (Hemiptera: Aleyrodidae)is on the move in Florida to residential landscapes and may impact open field agriculture

    USDA-ARS?s Scientific Manuscript database

    Bemisia tabaci MED (Mediterranean) have been in the United States for approximately a dozen years spreading to 26 states since it was first detected in Arizona at a retail outlet on poinsettia in 2004. Indistinguishable morphologically from silverleaf whitefly (Bemisia tabaci MEAM1 (Middle Eastern A...

  18. The Feeding Rate of Predatory Mites on Life Stages of Bemisia tabaci Mediterranean Species

    PubMed Central

    Cuthbertson, Andrew G. S.

    2014-01-01

    The sweetpotato whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) continues to be a serious threat to crops worldwide. The UK holds Protected Zone status against this pest and, as a result, B. tabaci entering on plant material is subjected to a policy of eradication. There has recently been a shift from Middle East-Asia Minor 1 to the more chemical resistant Mediterranean species entering the UK. Predatory mites (Amblyseius swirskii, Transeius montdorensis and Typhlodromalus limonicus) were screened for their impact upon various lifestages of B. tabaci Mediterranean species. Approximately 30% of eggs were fed upon by A. swirskii following a 5 day period. Feeding rates slightly decreased for all mite species when feeding on first instar life-stages (27%, 24%, 16% respectively) and significantly decreased when feeding on second instars (8.5%, 8.5%, 8.7% respectively). Combining the two mite species (A. swirskii and T. montdorensis) increased mortality of Bemisia eggs to 36%. The potential of incorporating the mites into existing control strategies for B. tabaci is discussed. PMID:26462828

  19. The Bemisia tabaci species complex: additions from different parts of the world.

    PubMed

    Firdaus, Syarifin; Vosman, Ben; Hidayati, Nurul; Jaya Supena, Ence Darmo; Visser, Richard G F; van Heusden, Adriaan Willem

    2013-12-01

    Bemisia tabaci is one of the most threatening pests in many crops. We sequenced part of the mitochondrial cytochrome oxidase I gene from fifty whitefly populations collected in Indonesia, Thailand, India and China. Nineteen unique sequences (haplotypes) of the cytochrome oxidase I were identified in these populations. They were combined with sequences available in databases, resulting in a total of 407 haplotypes and analyzed together with nine outgroup accessions. A phylogenetic tree was calculated using the maximum likelihood method. The tree showed that all groups that were found in previous studies were also present in our study. Additionally, seven new groups were identified based on the new haplotypes. Most B. tabaci haplotypes grouped based on their geographical origin. Two groups were found to have a worldwide distribution. Our results indicate that our knowledge on the species complex around B. tabaci is still far from complete.

  20. Wolbachia Has Two Different Localization Patterns in Whitefly Bemisia tabaci AsiaII7 Species

    PubMed Central

    Shi, Peiqiong; He, Zhan; Li, Shaojian; An, Xuan; Lv, Ning; Ghanim, Murad; Cuthbertson, Andrew G. S.; Ren, Shun-Xiang

    2016-01-01

    The whitefly Bemisia tabaci is a cosmopolitan insect species complex that harbors the obligate primary symbiont Portiera aleyrodidarum and several facultative secondary symbionts including Wolbachia, which have diverse influences on the host biology. Here, for the first time, we revealed two different localization patterns of Wolbachia present in the immature and adult stages of B. tabaci AsiaII7 cryptic species. In the confined pattern, Wolbachia was restricted to the bacteriocytes, while in the scattered pattern Wolbachia localized in the bacteriocytes, haemolymph and other organs simultaneously. Our results further indicated that, the proportion of B. tabaci AsiaII7 individuals with scattered Wolbachia were significantly lower than that of confined Wolbachia, and the distribution patterns of Wolbachia were not associated with the developmental stage or sex of whitefly host. This study will provide a new insight into the various transmission routes of Wolbachia in different whitefly species. PMID:27611575

  1. Wolbachia Has Two Different Localization Patterns in Whitefly Bemisia tabaci AsiaII7 Species.

    PubMed

    Shi, Peiqiong; He, Zhan; Li, Shaojian; An, Xuan; Lv, Ning; Ghanim, Murad; Cuthbertson, Andrew G S; Ren, Shun-Xiang; Qiu, Bao-Li

    2016-01-01

    The whitefly Bemisia tabaci is a cosmopolitan insect species complex that harbors the obligate primary symbiont Portiera aleyrodidarum and several facultative secondary symbionts including Wolbachia, which have diverse influences on the host biology. Here, for the first time, we revealed two different localization patterns of Wolbachia present in the immature and adult stages of B. tabaci AsiaII7 cryptic species. In the confined pattern, Wolbachia was restricted to the bacteriocytes, while in the scattered pattern Wolbachia localized in the bacteriocytes, haemolymph and other organs simultaneously. Our results further indicated that, the proportion of B. tabaci AsiaII7 individuals with scattered Wolbachia were significantly lower than that of confined Wolbachia, and the distribution patterns of Wolbachia were not associated with the developmental stage or sex of whitefly host. This study will provide a new insight into the various transmission routes of Wolbachia in different whitefly species.

  2. Deep Sequencing-Based Transcriptome Analysis Reveals the Regulatory Mechanism of Bemisia tabaci (Hemiptera: Aleyrodidae) Nymph Parasitized by Encarsia sophia (Hymenoptera: Aphelinidae)

    PubMed Central

    Wang, Ran; Li, Fei; Zhang, Fan; Wang, Su

    2016-01-01

    The whitefly Bemisia tabaci is a genetically diverse complex with multiple cryptic species, and some are the most destructive invasive pests of many ornamentals and crops worldwide. Encarsia sophia is an autoparasitoid wasp that demonstrated high efficiency as bio-control agent of whiteflies. However, the immune mechanism of B. tabaci parasitization by E. sophia is unknown. In order to investigate immune response of B. tabaci to E. Sophia parasitization, the transcriptome of E. sophia parasitized B. tabaci nymph was sequenced by Illumina sequencing. De novo assembly generated 393,063 unigenes with average length of 616 bp, in which 46,406 unigenes (15.8% of all unigenes) were successfully mapped. Parasitization by E. sophia had significant effects on the transcriptome profile of B. tabaci nymph. A total of 1482 genes were significantly differentially expressed, of which 852 genes were up-regulated and 630 genes were down-regulated. These genes were mainly involved in immune response, development, metabolism and host signaling pathways. At least 52 genes were found to be involved in the host immune response, 33 genes were involved in the development process, and 29 genes were involved in host metabolism. Taken together, the assembled and annotated transcriptome sequences provided a valuable genomic resource for further understanding the molecular mechanism of immune response of B. tabaci parasitization by E. sophia. PMID:27332546

  3. Lack of resistance development in Bemisia tabaci to Isaria fumosorosea after multiple generations of selection

    PubMed Central

    Gao, Tianni; Wang, Zhaolei; Huang, Yü; Keyhani, Nemat O.; Huang, Zhen

    2017-01-01

    The emergence of insecticide resistant insect pests is of significant concern worldwide. The whitefly, Bemisia tabaci, is an important agricultural pest and has shown incredible resilience developing resistance to a number of chemical pesticides. Entomopathogenic fungi such as Isaria fumosorosea offer an attractive alternative to chemical pesticides for insect control, and this fungus has been shown to be an effective pathogen of B. tabaci. Little is known concerning the potential for the development of resistance to I. fumosorosea by B. tabaci. Five generations of successive survivors of B. tabaci infected by I. fumosorosea were assayed with I. fumosorosea. No significant differences in susceptibility to I. fumosorosea, number of ovarioles, or ovipostioning were seen between any of the generations tested. Effects of I. fumosorosea and cell-free ethyl acetate fractions derived from the fungus on the B. tabaci fat body, ovary, and vitellogenin were also investigated. These data revealed significant deformation and degradation of ovary tissues and associated vitellogenin by the fungal mycelium as well as by cell-free ethyl acetate fungal extracts. These data indicate the lack of the emergence of resistance to I. fumosorosea under the conditions tested and demonstrate invasion of the insect reproductive tissues during fungal infection. PMID:28230074

  4. Lack of resistance development in Bemisia tabaci to Isaria fumosorosea after multiple generations of selection

    NASA Astrophysics Data System (ADS)

    Gao, Tianni; Wang, Zhaolei; Huang, Yü; Keyhani, Nemat O.; Huang, Zhen

    2017-02-01

    The emergence of insecticide resistant insect pests is of significant concern worldwide. The whitefly, Bemisia tabaci, is an important agricultural pest and has shown incredible resilience developing resistance to a number of chemical pesticides. Entomopathogenic fungi such as Isaria fumosorosea offer an attractive alternative to chemical pesticides for insect control, and this fungus has been shown to be an effective pathogen of B. tabaci. Little is known concerning the potential for the development of resistance to I. fumosorosea by B. tabaci. Five generations of successive survivors of B. tabaci infected by I. fumosorosea were assayed with I. fumosorosea. No significant differences in susceptibility to I. fumosorosea, number of ovarioles, or ovipostioning were seen between any of the generations tested. Effects of I. fumosorosea and cell-free ethyl acetate fractions derived from the fungus on the B. tabaci fat body, ovary, and vitellogenin were also investigated. These data revealed significant deformation and degradation of ovary tissues and associated vitellogenin by the fungal mycelium as well as by cell-free ethyl acetate fungal extracts. These data indicate the lack of the emergence of resistance to I. fumosorosea under the conditions tested and demonstrate invasion of the insect reproductive tissues during fungal infection.

  5. Lack of resistance development in Bemisia tabaci to Isaria fumosorosea after multiple generations of selection.

    PubMed

    Gao, Tianni; Wang, Zhaolei; Huang, Yü; Keyhani, Nemat O; Huang, Zhen

    2017-02-23

    The emergence of insecticide resistant insect pests is of significant concern worldwide. The whitefly, Bemisia tabaci, is an important agricultural pest and has shown incredible resilience developing resistance to a number of chemical pesticides. Entomopathogenic fungi such as Isaria fumosorosea offer an attractive alternative to chemical pesticides for insect control, and this fungus has been shown to be an effective pathogen of B. tabaci. Little is known concerning the potential for the development of resistance to I. fumosorosea by B. tabaci. Five generations of successive survivors of B. tabaci infected by I. fumosorosea were assayed with I. fumosorosea. No significant differences in susceptibility to I. fumosorosea, number of ovarioles, or ovipostioning were seen between any of the generations tested. Effects of I. fumosorosea and cell-free ethyl acetate fractions derived from the fungus on the B. tabaci fat body, ovary, and vitellogenin were also investigated. These data revealed significant deformation and degradation of ovary tissues and associated vitellogenin by the fungal mycelium as well as by cell-free ethyl acetate fungal extracts. These data indicate the lack of the emergence of resistance to I. fumosorosea under the conditions tested and demonstrate invasion of the insect reproductive tissues during fungal infection.

  6. Characterization of a Newly Discovered Symbiont of the Whitefly Bemisia tabaci (Hemiptera: Aleyrodidae)

    PubMed Central

    Bing, Xiao-Li; Yang, Jiao; Zchori-Fein, Einat; Wang, Xiao-Wei

    2013-01-01

    Bemisia tabaci (Hemiptera: Aleyrodidae) is a species complex containing >28 cryptic species, some of which are important crop pests worldwide. Like many other sap-sucking insects, whiteflies harbor an obligatory symbiont, “Candidatus Portiera aleyrodidarum,” and a number of secondary symbionts. So far, six genera of secondary symbionts have been identified in B. tabaci. In this study, we report and describe the finding of an additional bacterium in the indigenous B. tabaci cryptic species China 1 (formerly known as B. tabaci biotype ZHJ3). Phylogenetic analysis based on the 16S rRNA and gltA genes showed that the bacterium belongs to the Alphaproteobacteria subdivision of the Proteobacteria and has a close relationship with human pathogens of the genus Orientia. Consequently, we temporarily named it Orientia-like organism (OLO). OLO was found in six of eight wild populations of B. tabaci China 1, with the infection rate ranging from 46.2% to 76.8%. Fluorescence in situ hybridization (FISH) of B. tabaci China 1 in nymphs and adults revealed that OLOs are confined to the bacteriome and co-occur with “Ca. Portiera aleyrodidarum.” The vertical transmission of OLO was demonstrated by detection of OLO at the anterior pole end of the oocytes through FISH. Quantitative PCR analysis of population dynamics suggested a complex interaction between “Ca. Portiera aleyrodidarum” and OLO. Based on these results, we propose “Candidatus Hemipteriphilus asiaticus” for the classification of this symbiont from B. tabaci. PMID:23144129

  7. Global haplotype analysis of the whitefly Bemisia tabaci cryptic species Asia I in Asia.

    PubMed

    Hu, Jian; Chen, Yong-Dui; Jiang, Zhi-Lin; Nardi, Francesco; Yang, Tai-Yuan; Jin, Jie; Zhang, Zhong-Kai

    2015-04-01

    The whitefly, Bemisia tabaci (Hemiptera: Aleyrodidiae), is a cryptic species complex comprising a minimum of 24 cryptic species. Some members of this complex are important agricultural pests, causing considerable damage to vegetable as well as ornamental and horticultural crops. Asia I, one of the cryptic species of B. tabaci, is widely distributed in Asia. One hundred and sixty mitochondrial cytochrome oxidase I (COI) sequences from eight countries have been analyzed to investigate the geographic origin and current genetic structure of this cryptic species. Sixty different haplotypes were identified, with levels of genetic distances ranging from 0.001 to 0.021. A sign of possible genetic differentiation emerges from the differential distribution of dominant haplotypes in Indonesia and India compared to China. A possible ancient separation between Asia I in India and Indonesia and secondary contact in China has been hypothesized.

  8. Detoxification enzymes of Bemisia tabaci B and Q: biochemical characteristics and gene expression profiles.

    PubMed

    Guo, Litao; Xie, Wen; Wang, Shaoli; Wu, Qingjun; Li, Rumei; Yang, Nina; Yang, Xin; Pan, Huipeng; Zhang, Youjun

    2014-10-01

    The sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is one of the most invasive and destructive pests of field crops worldwide. The sibling species B and Q are the two most damaging members of the B. tabaci species complex. That Q is more resistant than B to many insecticides has been well documented. Over the last decade, Q has gradually displaced B and has become the dominant form of B. tabaci in field agricultural systems in most parts of China. To help understand the differences in insecticide resistance, the activities and gene expression profiles of detoxification enzymes in B. tabaci B and Q were investigated. The activity of P450 towards 7-ethoxycoumarin was significantly higher (1.46-fold higher) in Q than in B. The expression of 43 of 65 P450 genes was higher (>1-fold) in Q than in B, and expression for eight P450 genes was more than 50-fold greater in Q than in B. The increased expression of selected P450 genes in Q relative to B was confirmed with two other B strains and two other Q strains. On the other hand, carboxylesterase (CarE) activity was significantly lower (0.71-fold lower) in Q than in B; the Km value of CarE was significantly lower in B than in Q, but the opposite was true for the Vmax value of CarE. Glutathione S-transferase activity and values of Km and Vmax did not differ between B and Q. Enhanced metabolic detoxification of insecticides by P450s may be an important reason why B. tabaci Q is more resistant than B. tabaci B to insecticides. © 2014 Society of Chemical Industry.

  9. Species within the Bemisia tabaci (Hemiptera: Aleyrodidae) complex in soybean and bean crops in Argentina.

    PubMed

    Alemandri, V; De Barro, P; Bejerman, N; Argüello Caro, E B; Dumón, A D; Mattio, M F; Rodriguez, S M; Truoli, G

    2012-02-01

    The whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a cryptic species complex that contains some of the most damaging pests in tropical and subtropical regions. Recent studies suggested that this complex is composed of at least 24 distinct species. We use the approach from these studies to consider the identity of B. tabaci in Argentina. Previous studies have suggested the presence of a B. tabaci presumably indigenous to the Americas and referred to as the BR biotype in Argentina. We placed the entity referred to as the BR biotype within the B. tabaci cryptic species complex using whiteflies collected in soybean and bean crops in northern and central Argentina. The whiteflies were assigned using the mitochondrial cytochrome oxidase (mtCOI) gene. Four unknown haplotypes plus two Argentina sequences from GenBank formed a cluster that was basal to the rest of the New World sequences. These sequences diverged from the consensus sequence across the range of 3.6 to 4.3%. Applying the species assignment rules of recent studies suggests that the individuals from Argentina form a separate species. A fifth unknown haplotype fell within the New World putative species and formed a distinct cluster with haplotypes from Panama. These results suggest that Argentina has two indigenous species belonging to the B. tabaci cryptic species complex. Rather than using mtCOI sequencing for all B. tabaci collected, a simple random amplified polymorphic DNA-polymerase chain reaction diagnostic was used and tested along with previously published primers designed to work specifically with the BR biotype from Brazil. These primers were either unable to distinguish between the two indigenous members of the complex in Argentina or indicated a difference when none was evident on the basis of mtCOI sequence comparison.

  10. Cross-resistance relationships between neonicotinoids and pymetrozine in Bemisia tabaci (Hemiptera: Aleyrodidae).

    PubMed

    Gorman, Kevin; Slater, Russell; Blande, James D; Clarke, Alison; Wren, Jodie; McCaffery, Alan; Denholm, Ian

    2010-11-01

    Although cross-resistance between compounds in the same insecticide group is a frequently observed phenomenon, cross-resistance between groups that differ in structural and functional characteristics can be extremely unpredictable. In the case of controlling the whitefly, Bemisia tabaci Gennadius, neonicotinoids and the pyridine azomethine antifeedant pymetrozine represent independent lines of discovery that should be suited for alternation to avoid prolonged selection for the same resistance mechanism. Reports of an association between responses to neonicotinoids and pymetrozine were investigated by resistance profiling of seven B. tabaci strains and complementary reciprocal selection experiments. All strains demonstrated a consistent correlation between responses to three neonicotinoid compounds: thiamethoxam, imidacloprid and acetamiprid. Responses to neonicotinoids for six field strains clearly correlated with responses to pymetrozine. Reciprocal selection experiments confirmed an unexpected case of intergroup cross-resistance. A seventh strain exhibited a so far unique phenotype of strong resistance to pymetrozine but full susceptibility to neonicotinoids. Selection experiments confirmed that in this strain the mechanism of pymetrozine resistance is specific and has no implications for neonicotinoids. Cross-resistance between neonicotinoids and pymetrozine in B. tabaci probably reflects the overexpression of a cytochrome-P450-dependent monooxygenase capable of metabolising both types of compound in spite of their apparent structural dissimilarity. Given the predominance of this mechanism in B. tabaci, both can contribute to resistance management but should be placed within the same treatment 'window'. Copyright © 2010 Society of Chemical Industry.

  11. Odor, Not Performance, Dictates Bemisia tabaci's Selection between Healthy and Virus Infected Plants.

    PubMed

    Chen, Gong; Su, Qi; Shi, Xiaobin; Liu, Xin; Peng, Zhengke; Zheng, Huixin; Xie, Wen; Xu, Baoyun; Wang, Shaoli; Wu, Qingjun; Zhou, Xuguo; Zhang, Youjun

    2017-01-01

    Although, insect herbivores are generally thought to select hosts that favor the fitness of their progeny, this "mother-knows-best" hypothesis may be challenged by the presence of a plant virus. Our previous study showed that the whitefly, Bemisia tabaci, the obligate vector for transmitting Tomato yellow leaf curl virus (TYLCV), preferred to settle and oviposit on TYLCV-infected rather than healthy host plant, Datura stramonium. The performances of B. tabaci larvae and adults were indeed improved on virus-infected D. stramonium, which is consistent with "mother-knows-best" hypothesis. In this study, B. tabaci Q displayed the same preference to settle and oviposit on Tomato spotted wilt virus (TSWV)-infected host plants, D. stramonium and Capsicum annuum, respectively. As a non-vector of TSWV, however, insect performance was impaired since adult body size, longevity, survival, and fecundity were reduced in TSWV infected D. stramonium. This appears to be an odor-mediated behavior, as plant volatile profiles are modified by viral infection. Infected plants have reduced quantities of o-xylene and α-pinene, and increased levels of phenol and 2-ethyl-1-hexanol in their headspace. Subsequent behavior experiments showed that o-xylene and α-pinene are repellant, while phenol and 2-ethyl-1-hexanol are attractive. This indicates that the preference of B. tabaci for virus-infected plants is modulated by the dynamic changes in the volatile profiles rather than the subsequent performances on virus-infected plants.

  12. Field-Evolved Resistance of Bemisia tabaci (Hemiptera: Aleyrodidae) to Carbodiimide and Neonicotinoids in Pakistan.

    PubMed

    Ahmad, Mushtaq; Khan, Rashid A

    2017-03-03

    The evolution of resistance to carbodiimide (a toxic metabolite of diafenthiuron) and four neonicotinoids imidacloprid, acetamiprid, thiamethoxam, and thiacloprid in the Pakistani populations of sweetpotato whitefly (Bemisia tabaci Gennadius) was monitored from 1996 to 2015 using a leaf-dip bioassay. Diafenthiuron, imidacloprid, and acetamiprid were introduced into Pakistani agriculture in mid-1990s and heavily used since then, because B. tabaci resistance and consequently control failures to conventional insecticides such as organophosphates, carbamates, and pyrethroids were widespread during the 1990s. According to the current studies, resistance to carbodiimide, imidacloprid, and acetamiprid during 1996-2010 and to thiamethoxam during 1999-2007 remained very low, but then it rose sharply, and by the year 2015, the B. tabaci resistance increased to very high levels. Among neonicotinoids, thiacloprid was the latest introduction in Pakistan in 2002. There was no thiacloprid resistance in 2002 and 2003, a low to moderate resistance during 2004-2006, and a very high resistance during 2007-2010 that even exceeded resistance to previous neonicotinoids. We may conclude that diafenthiuron and neonicotinoids remained effective against B. tabaci for 15 yr following their intensive use under field conditions, before a significant resistance, leading to their field failures, occurred in Pakistan.

  13. Genetic structure of the whitefly Bemisia tabaci populations in Colombia following a recent invasion.

    PubMed

    Díaz, Fernando; Endersby, Nancy M; Hoffmann, Ary A

    2015-08-01

    The whitefly Bemisia tabaci (Gennadius) is one of the most important pests causing economic losses in a variety of cropping systems around the world. This species was recently found in a coastal region of Colombia and has now spread inland. To investigate this invasive process, the genetic structure of B. tabaci was examined in 8 sampling locations from 2 infested regions (coastal, inland) using 9 microsatellite markers and the mitochondrial COI gene. The mitochondrial analysis indicated that only the invasive species of the B. tabaci complex Middle East-Asia Minor 1 (MEAM 1 known previously as biotype B) was present. The microsatellite data pointed to genetic differences among the regions and no isolation by distance within regions. The coastal region in the Caribbean appears to have been the initial point of invasion, while the inland region in the Southwest showed genetic variation among populations most likely reflecting founder events and ongoing changes associated with climatic and topographical heterogeneity. These findings have implications for tracking and managing B. tabaci. © 2014 Institute of Zoology, Chinese Academy of Sciences.

  14. Species and endosymbiont diversity of Bemisia tabaci (Homoptera: Aleyrodidae) on vegetable crops in Senegal.

    PubMed

    Hélène, Delatte; Rémy, Baudin; Nathalie, Becker; Anne-Laure, Girard; Traoré, Ramatoulaye Sidebe; Jean-Michel, Lett; Bernard, Reynaud

    2015-03-01

    Bemisia tabaci-transmitted geminiviruses are one of the major threats on cassava and vegetable crops in Africa. However, to date, few studies are available on the diversity of B. tabaci and their associated endosymbionts in Africa. More than 28 species have been described in the complex of B. tabaci cryptic species; among them, 2 are invasive pests worldwide: MED and MEAM1. In order to assess the species diversity of B. tabaci in vegetable crops in Senegal, several samplings in different localities, hosts and seasons were collected and analyzed with nuclear (microsatellite) and mitochondrial (COI) markers. The bacterial endosymbiont community was also studied for each sample. Two species were detected: MED Q1 and MEAM1 B. Patterns of MED Q1 (dominance on most of the samples and sites, highest nuclear and mitochondrial diversity and broader secondary endosymbiont community: Hamiltonella, Cardinium, Wolbachia and Rickettsia), point toward a predominant resident begomovirus vector group for MED Q1 on market gardening crops. Furthermore, the lower prevalence of the second species MEAM1 B, its lower nuclear and mitochondrial diversity and a narrower secondary endosymbiont community (Hamiltonella/Rickettsia), indicate that this genetic group is exotic and results from a recent invasion in this area. © 2014 Institute of Zoology, Chinese Academy of Sciences.

  15. Odor, Not Performance, Dictates Bemisia tabaci's Selection between Healthy and Virus Infected Plants

    PubMed Central

    Chen, Gong; Su, Qi; Shi, Xiaobin; Liu, Xin; Peng, Zhengke; Zheng, Huixin; Xie, Wen; Xu, Baoyun; Wang, Shaoli; Wu, Qingjun; Zhou, Xuguo; Zhang, Youjun

    2017-01-01

    Although, insect herbivores are generally thought to select hosts that favor the fitness of their progeny, this “mother-knows-best” hypothesis may be challenged by the presence of a plant virus. Our previous study showed that the whitefly, Bemisia tabaci, the obligate vector for transmitting Tomato yellow leaf curl virus (TYLCV), preferred to settle and oviposit on TYLCV-infected rather than healthy host plant, Datura stramonium. The performances of B. tabaci larvae and adults were indeed improved on virus-infected D. stramonium, which is consistent with “mother-knows-best” hypothesis. In this study, B. tabaci Q displayed the same preference to settle and oviposit on Tomato spotted wilt virus (TSWV)-infected host plants, D. stramonium and Capsicum annuum, respectively. As a non-vector of TSWV, however, insect performance was impaired since adult body size, longevity, survival, and fecundity were reduced in TSWV infected D. stramonium. This appears to be an odor-mediated behavior, as plant volatile profiles are modified by viral infection. Infected plants have reduced quantities of o-xylene and α-pinene, and increased levels of phenol and 2-ethyl-1-hexanol in their headspace. Subsequent behavior experiments showed that o-xylene and α-pinene are repellant, while phenol and 2-ethyl-1-hexanol are attractive. This indicates that the preference of B. tabaci for virus-infected plants is modulated by the dynamic changes in the volatile profiles rather than the subsequent performances on virus-infected plants. PMID:28360861

  16. Feasible sampling plan for Bemisia tabaci control decision-making in watermelon fields.

    PubMed

    Lima, Carlos Ho; Sarmento, Renato A; Pereira, Poliana S; Galdino, Tarcísio Vs; Santos, Fábio A; Silva, Joedna; Picanço, Marcelo C

    2017-11-01

    The silverleaf whitefly Bemisia tabaci is one of the most important pests of watermelon fields worldwide. Conventional sampling plans are the starting point for the generation of decision-making systems of integrated pest management programs. The aim of this study was to determine a conventional sampling plan for B. tabaci in watermelon fields. The optimal leaf for B. tabaci adult sampling was the 6(th) most apical leaf. Direct counting was the best pest sampling technique. Crop pest densities fitted the negative binomial distribution and had a common aggregation parameter (Kcommon ). The sampling plan consisted of evaluating 103 samples per plot. This sampling plan was conducted for 56 min, costing US$ 2.22 per sampling and with a 10% maximum evaluation error. The sampling plan determined in this study can be adopted by farmers because it enables the adequate evaluation of B. tabaci populations in watermelon fields (10% maximum evaluation error) and is a low-cost (US$ 2.22 per sampling), fast (56 min per sampling) and feasible (because it may be used in a standardized way throughout the crop cycle) technique. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  17. Acylsucrose-Producing Tomato Plants Forces Bemisia tabaci to Shift Its Preferred Settling and Feeding Site

    PubMed Central

    Rodríguez-López, Maria Jose; Garzo, Elisa; Bonani, Jean Patrick; Fernández-Muñoz, Rafael; Moriones, Enrique; Fereres, Alberto

    2012-01-01

    Background The whitefly Bemisia tabaci (Genn.) causes dramatic damage to plants by transmitting yield-limiting virus diseases. Previous studies proved that the tomato breeding line ABL 14-8 was resistant to B. tabaci, the vector of tomato yellow leaf curl disease (TYLCD). This resistance is based on the presence of type IV glandular trichomes and acylsucrose production. These trichomes deter settling and probing of B. tabaci in ABL 14-8, which reduces primary and secondary spread of TYLCD. Methodology/Principal Findings Whitefly settlement preference was evaluated on the adaxial and abaxial leaf surfaces of nearly-isogenic tomato lines with and without B. tabaci-resistance traits, ‘ABL 14-8 and Moneymaker’ respectively, under non-choice and free-choice conditions. In addition, the Electrical Penetration Graph technique was used to study probing and feeding activities of B. tabaci on the adaxial and abaxial leaf surfaces of the same genotypes. B. tabaci preferred to settle on the abaxial than on the adaxial surface of ‘Moneymaker’ leaves, whereas no such preference was observed on ABL 14-8 tomato plants at the ten-leaf growth stage. Furthermore, B. tabaci preferred to feed on the abaxial than on the adaxial leaf surface of ‘Moneymarker’ susceptible tomato plants as shown by a higher number of sustained phloem feeding ingestion events and a shorter time to reach the phloem. However, B. tabaci standard probing and feeding behavior patterns were altered in ABL 14-8 plants and whiteflies were unable to feed from the phloem and spent more time in non-probing activities when exposed to the abaxial leaf surface. Conclusions/Significance The distorted behavior of B. tabaci on ABL 14-8 protects tomato plants from the transmission of phloem-restricted viruses such as Tomato yellow leaf curl virus (TYLCV), and forces whiteflies to feed on the adaxial side of leaves where they feed less efficiently and become more vulnerable to natural enemies. PMID:22427950

  18. Pathogenicity of Isaria sp. (Hypocreales: Clavicipitaceae)against the sweetpotato whitefly B biotype, Bemisia tabaci (Hemiptera: Aleyrodidae)

    USDA-ARS?s Scientific Manuscript database

    The pathogenicity of an indigenous entomopathogenic fungus, Isaria sp., found during natural epizootics on whiteflies in the Lower Rio Grande Valley of Texas, against the sweetpotato whitefly, Bemisia tabaci Gennadius biotype B, was tested under laboratory conditions (27 ºC, 70% RH and a photoperiod...

  19. Comparison of three single-nozzle operator-carried spray applicators for whitefly (Bemisia tabaci) management on squash

    USDA-ARS?s Scientific Manuscript database

    Whiteflies cause problems in vegetable production on a global scale. The primary worldwide whitefly pest is Bemisia tabaci (Gennadius). Insecticides are commonly used to mitigate the whitefly problem in vegetable crops. In limited-resource crop production, operator-carried spray applicators are comm...

  20. Taxonomic status of the Bemisia tabaci complex (Hemiptera: Aleyrodidae) and reassessment of the number of its constituent species.

    PubMed

    Lee, Wonhoon; Park, Jongsun; Lee, Gwan-Seok; Lee, Seunghwan; Akimoto, Shin-ichi

    2013-01-01

    Bemisia tabaci (Hemiptera: Aleyrodidae) is one of the most important insect pests in the world. In the present study, the taxonomic status of B. tabaci and the number of species composing the B. tabaci complex were determined based on 1059 COI sequences of B. tabaci and 509 COI sequences of 153 hemipteran species. The genetic divergence within B. tabaci was conspicuously higher (on average, 11.1%) than interspecific genetic divergence within the respective genera of the 153 species (on average, 6.5%). This result indicates that B. tabaci is composed of multiple species that may belong to different genera or subfamilies. A phylogenetic tree constructed based on 212 COI sequences without duplications revealed that the B. tabaci complex is composed of a total of 31 putative species, including a new species, JpL. However, genetic divergence within six species (Asia II 1, Asia II 7, Australia, Mediterranean, New World, and Sub Saharan Africa 1) was higher than 3.5%, which has been used as a threshold of species boundaries within the B. tabaci complex. These results suggest that it is necessary to increase the threshold for species boundaries up to 4% to distinguish the constituent species in the B. tabaci complex.

  1. Repellent effect of alphacypermethrin-treated netting against Bemisia tabaci (Hemiptera: Aleyrodidae).

    PubMed

    Martin, T; Kamal, A; Gogo, E; Saidi, M; Delétré, E; Bonafos, R; Simon, S; Ngouajio, M

    2014-04-01

    For > 20 yr, Bemisia tabaci Gennadius persists as a begomovirus vector and is a serious problem in tomato production in many parts of the world. In tropical countries, the use of netting to protect horticultural crops has proven to be an effective and sustainable tool against Lepidoptera but not against small insects. This study evaluated the repellent effect of AgroNet 0.9T, a 0.9-mm pore diameter and 40-mesh size netting treated with alphacypermethrin insecticide against B. tabaci. This pyrethroid insecticide is known to have toxic and repellent effects against mosquitoes and has been used for treatment of mosquito nets. Two nontreated netting materials were used as control: AgroNet 0.9NT with 0.9-mm pore diameter and 40-mesh size and AgroNet 0.4NT with 0.4-mm pore diameter and 80-mesh size. The behavior of B. tabaci and its parasitoid Encarsia formosa Gahan as they progressed through the treated netting was studied in the laboratory in choice and no-choice tests. The development of wild B. tabaci population on tomato plants protected by the same nets was followed in two field trials implemented in Njoro, Kenya. Results obtained with the no-choice tests showed a significant reduction of movement on the treated net with 40-mesh (19%) compared with nontreated netting (35 and 46% with 80- and 40-mesh, respectively). The mortality of B. tabaci was significantly higher (two-fold) in the test tube containing only the treated netting compared with the nontreated one. The repellent effect of the treated netting was also demonstrated against E. formosa, but it did not have this toxic effect. Unlike for B. tabaci, the treated and nontreated nets appeared to have a similar repellent effect on E. formosa in the choice test, which suggests a learning behavior of the parasitoid. In both field tests, B. tabaci population was significantly lower on tomato protected by the treated net compared with the same nontreated net. However there was no significant difference in B. tabaci

  2. Effects of selected fertilizers on the life history of Bemisia tabaci (Hemiptera: Aleyrodidae) biotype B.

    PubMed

    England, K M; Sadof, C S; Cañnas, L A; Kuniyoshi, C H; Lopez, R G

    2011-04-01

    We tested the effects among a purportedly sustainable water-soluble fertilizer, a conventional water-soluble fertilizer, an alternation of these, a controlled-release fertilizer, and a clear water control on the life-history traits of sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae; =Bemisia argentifolii Bellows & Perring) biotype B reared on poinsettia (Euphorbia pulcherrima Willdenow ex Klotzch). Free amino acids in petioles were measured to estimate plant nutrient assimilation and phloem nutritional quality for B. tabaci biotype B. The sustainable fertilizer produced plants with the highest concentration of amino acids. In contrast, fecundity of whiteflies was lowest in plants treated with the sustainable fertilizer and the water control. The relationship between total amino acids in phloem and survival was significantly quadratic, with the highest survival at intermediate levels. Fecundity, however, was negatively correlated with total amino acid content of the maternal host plant. Variation in total amino acid concentration in petioles of plants treated within fertilizer treatments makes it difficult to predict whether a particular fertilizer will produce plants with enough amino acids to deleteriously affect both survivorship and fecundity and yet yield a plant of good quality. Despite this limitation, we can conclude that the use of this sustainable fertilizer will not cause increases in whitefly populations relative to plants fertilized with water-soluble and slow-release fertilizers that deliver the same level of nitrogen to the plant.

  3. Interactions Between Cassava Mosaic Geminiviruses and Their Vector, Bemisia tabaci (Hemiptera: Aleyrodidae).

    PubMed

    Boni, Simon B; Rugumamu, Costancia P; Gerling, Dan; Sagary Nokoe, K; Legg, James P

    2017-06-01

    The sweetpotato whitefly, Bemisia tabaci (Gennadius) is the vector of the cassava mosaic geminiviruses (CMGs) that cause cassava mosaic disease (CMD). Synergistic interactions between B. tabaci and CMGs have been hypothesized as a cause of whitefly "super-abundance," which has been a key factor behind the spread of the severe CMD pandemic through East and Central Africa. The current study investigated this hypothesis by conducting experiments with CMD-susceptible cassava varieties infected with different CMGs in both the north-western Lake Zone region (pandemic affected) and the eastern Coast Zone where CMD is less severe. Male and female pairs of B. tabaci were placed in clip cages for 48 h on plants of three cassava varieties at each of the two locations. There were significantly more eggs laid on CMG-infected than on CMG-free plants in the Lake Zone, whereas in Coast Zone, there were no significant differences. There were no significant differences in proportions, mortality, and development duration of immature stages of B. tabaci among virus states and cassava variety in the two locations. The overall number of eggs was significantly higher with longer development duration of the immature stages in the Lake than in the Coast Zone, whereas mortality was significantly higher in the Coast than in the Lake Zone. Based on these results, it is concluded that there was no net positive synergistic interaction between CMGs and B. tabaci for either lowland coastal or mid-altitude inland populations. Consequently, other factors seem more likely to be the cause of the "super-abundance," and require further investigation. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  4. Olfactory response of predatory Macrolophus caliginosus Wagner (Heteroptera: Miridae) to the odours host plant infested by Bemisia tabaci

    NASA Astrophysics Data System (ADS)

    Saad, Khalid A.; Roff, M. N. Mohamad; Salam, Mansour; Hanifah Mohd, Y.; Idris, A. B.

    2014-09-01

    Plant infested with herbivores, release volatile that can be used by natural enemies to locate their herbivorous prey. Laboratory studies were carried out to determine the olfactory responses of predator Macrolophus caliginosus Wagner (Heteroptera: Miridae), to chili plant infected with eggs, nymphs of Bemisia tabaci, using Y-tube olfactometer. The results shown that predator, M. caliginosus has ability to discriminate between non-infested and infested plant by B. tabaci. Moreover, the predator preferred plants with nymphs over plants with eggs. This suggested that M. caliginous uses whitefly-induced volatile as reliable indicators to distinguish between infested chili plants by nymphs, eggs and non-infested plants. These results enhance our understanding of the olfactory cues that guide foraging by M. caliginosus to plant with and without Bemisia tabaci.

  5. Standardised molecular diagnostic tool for the identification of cryptic species within the Bemisia tabaci complex.

    PubMed

    Elfekih, S; Tay, W T; Gordon, K; Court, L; De Barro, P

    2017-07-23

    The whitefly Bemisia tabaci complex harbours over 40 cryptic species that have been placed in 11 phylogenetically distinct clades based on the molecular characterisation of partial mitochondrial DNA COI (mtCOI) gene region. Four cryptic species are currently within the invasive clade i.e. 'MED', 'MEAM1', 'MEAM2' and IO'. Correct identification of these species is a critical step towards implementing reliable measures for plant biosecurity and border protection, however no standardised B. tabaci-specific primers are currently available which has caused inconsistencies in the species identification processes. We report three sets of PCR primers developed to amplify the mtCOI region which can be used for genotyping 'MED', 'MEAM1', and 'IO' species and tested these primers on 91 MED, 35 MEAM1 and five IO individuals. PCR and sequencing of amplicons identified a total of 21, six and one haplotypes in MED, MEAM1 and IO respectively, of which six haplotypes were new to the B. tabaci database. These primer pairs enabled standardisation and robust molecular species identification via mtCOI screening of the targeted invasive cryptic species and will improve quarantine decisions. The use of this diagnostic tool could be extended to other species within the complex. This article is protected by copyright. All rights reserved.

  6. Extraordinary resistance to insecticides reveals exotic Q biotype of Bemisia tabaci in the New World.

    PubMed

    Dennehy, Timothy J; Degain, Benjamin A; Harpold, Virginia S; Zaborac, Marni; Morin, Shai; Fabrick, Jeffrey A; Nichols, Robert L; Brown, Judith K; Byrne, Frank J; Li, Xianchun

    2010-12-01

    A strain of the whitefly Bemisia tabaci (Gennadius) possessing unusually high levels of resistance to a wide range of insecticides was discovered in 2004 in the course of routine resistance monitoring in Arizona. The multiply resistant insects, collected from poinsettia (Euphorbia pulcherrima Willd. ex Klotzsch) plants purchased at a retail store in Tucson, were subjected to biotype analysis in three laboratories. Polyacrylamide gel electrophoresis of naphthyl esterases and sequencing of the mitochondrial cytochrome oxidase I gene (780 bp) confirmed the first detection of the Q biotype of B. tabaci in the New World. This U.S. Q biotype strain, referred to as Poinsettia'04, was highly resistant to two selective insect growth regulators, pyriproxyfen and buprofezin, and to mixtures of fenpropathrin and acephate. It was also unusually low in susceptibility to the neonicotinoid insecticides imidacloprid, acetamiprid, and thiamethoxam, relative to B biotype whiteflies. In 100 collections of whiteflies made in Arizona cotton (Gossypium spp.), vegetable, and melon (Cucumis melo L.) fields from 2001 to 2005, no Q biotypes were detected. Regions of the United States that were severely impacted by the introduction of the B biotype of B. tabaci in the 1980s would be well advised to promote measures that limit movement of the Q biotype from controlled environments into field systems and to formulate alternatives for managing this multiply-resistant biotype, in the event that it becomes more widely distributed.

  7. Aphid-induced Defences in Chilli Affect Preferences of the Whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae).

    PubMed

    Saad, Khalid A; Mohamad Roff, M N; Hallett, Rebecca H; Idris, A B

    2015-09-03

    The sweetpotato whitefly (WF), Bemisia tabaci, is a major pest that damages a wide range of vegetable crops in Malaysia. WF infestation is influenced by a variety of factors, including previous infestation of the host plant by other insect pests. This study investigated the effects of previous infestation of host chilli plants by the green peach aphid (Myzus persicae) on the olfactory behavioural response of B. tabaci, using free-choice bioassay with a Y-tube olfactometer. We analysed volatile organic compounds (VOCs) emitted by non-infested and M. persicae-infested chilli plants using solid-phase microextraction and gas chromatography-mass spectrometry. Our results showed that female WFs preferred non-infested to pre-infested plants. Collection and analysis of volatile compounds emitted by infested plants confirmed that there were significant increases in the production of monoterpenes (cymene; 1,8-cineole), sesquiterpenes (β-cadinene, α-copaene), and methyl salicylate (MeSA) compared to non-infested plants. Our results suggest that host plant infestation by aphids may induce production of secondary metabolites that deter B. tabaci from settling on its host plants. These results provide important information for understanding WF host selection and dispersal among crops, and also for manipulating WF behaviour to improve IPM in chilli.

  8. Factors Affecting Population Dynamics of Maternally Transmitted Endosymbionts in Bemisia tabaci

    PubMed Central

    Pan, Huipeng; Li, Xianchun; Ge, Daqing; Wang, Shaoli; Wu, Qingjun; Xie, Wen; Jiao, Xiaoguo; Chu, Dong; Liu, Baiming; Xu, Baoyun; Zhang, Youjun

    2012-01-01

    While every individual of Bemisia tabaci (Hemiptera: Aleyrodidae) harbors the primary symbiont (P-symbiont) Portiera, the infection frequencies of the six secondary symbionts (S-symbionts) including Hamiltonella, Arsenophonus, Cardinium, Wolbachia, Rickettsia and Fritschea vary greatly among different populations. To characterize the factors influencing the infection dynamics of the six S-symbionts in B. tabaci, gene-specific PCR were conducted to screen for the presence of the P-symbiont Portiera and the six S-symbionts in 61 (17 B and 44 Q biotypes) field populations collected from different plant species and locations in China. All individuals of the 61 populations hosted the P-symbiont Portiera, but none of them harbored Arsenophonus and Fritschea. The presence and infection rates of Hamiltonella, Cardinium, Rickettsia, Wolbachia and their co-infections Rickettsia + Hamiltonella (RH), Rickettsia + Cardinium (RC), Hamiltonella + Cardinium (HC) and Rickettsia + Hamiltonella + Cardinium (RHC) varied significantly among the 61 field populations; and the observed variations can be explained by biotypes, sexes, host plants and geographical locations of these field populations. Taken together, at least three factors including biotype, host plant and geographical location affect the infection dynamics of S-symbionts in B. tabaci. PMID:22383972

  9. Aphid-induced Defences in Chilli Affect Preferences of the Whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae)

    PubMed Central

    Saad, Khalid A.; Mohamad Roff, M. N.; Hallett, Rebecca H.; Idris, A. B.

    2015-01-01

    The sweetpotato whitefly (WF), Bemisia tabaci, is a major pest that damages a wide range of vegetable crops in Malaysia. WF infestation is influenced by a variety of factors, including previous infestation of the host plant by other insect pests. This study investigated the effects of previous infestation of host chilli plants by the green peach aphid (Myzus persicae) on the olfactory behavioural response of B. tabaci, using free-choice bioassay with a Y-tube olfactometer. We analysed volatile organic compounds (VOCs) emitted by non-infested and M. persicae-infested chilli plants using solid-phase microextraction and gas chromatography–mass spectrometry. Our results showed that female WFs preferred non-infested to pre-infested plants. Collection and analysis of volatile compounds emitted by infested plants confirmed that there were significant increases in the production of monoterpenes (cymene; 1,8-cineole), sesquiterpenes (β–cadinene, α-copaene), and methyl salicylate (MeSA) compared to non-infested plants. Our results suggest that host plant infestation by aphids may induce production of secondary metabolites that deter B. tabaci from settling on its host plants. These results provide important information for understanding WF host selection and dispersal among crops, and also for manipulating WF behaviour to improve IPM in chilli. PMID:26334135

  10. Oviposition, Development and Survivorship of the sweetpotato Whitefly Bemisia tabaci on Soybean, Glycine max, and the Garden Bean, Phaseolus vulgaris

    PubMed Central

    Mansaray, Augustine; Sundufu, Abu James

    2009-01-01

    Oviposition, development and survivorship of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) were evaluated on soybean and garden bean under laboratory conditions of 26.0 ± 0.5 °C, 70 – 80% RH and a photoperiod of 14:10 (L:D). B. tabaci deposited more eggs and survivorship of nymphs was significantly greater in a choice-test on soybean, Glycine max L. (Merr.) (Fabeles: Fabaceae), compared to the garden bean, Phaseolus vulgaris L. Overall developmental time from egg to adult eclosion was longer on garden bean than on soybean. Also, B. tabaci was more fecund and long-lived on soybean compared to garden bean. Demographic parameters calculated from life tables on the two bean species indicate that soybean is a better host plant for B. tabaci than garden bean. PMID:19611218

  11. Characterization of Antixenosis in Soybean Genotypes to Bemisia tabaci (Hemiptera: Aleyrodidae) Biotype B.

    PubMed

    Baldin, E L L; Cruz, P L; Morando, R; Silva, I F; Bentivenha, J P F; Tozin, L R S; Rodrigues, T M

    2017-08-01

    Bemisia tabaci biotype B (Gennadius) is one of the most important soybean pest worldwide. Herein, 15 soybean genotypes were evaluated, to characterize the occurrence of antixenosis to B. tabaci biotype B. Initially, a multiple-choice test with all genotypes was carried out, evaluating the settling and oviposition preference at 3 d after infestation, and the colonization by nymphs after 48 d of infestation. Subsequently, a no-choice test, using 14 genotypes, was conducted with infested plants individually, and the number of eggs was counted after 72 h. Then, 10 genotypes were selected (indicative of resistance and susceptibility), which were evaluated for whitefly settling 24, 48, and 72 h after infestation and for oviposition 72 h after infestation. The trichomes of the leaflets were characterized for density, size, and inclination to establish possible correlations with the settling and oviposition in the genotypes. In the first multiple-choice test, involving 15 genotypes, 'IAC-17,' 'IAC-19,' and UX-2569-159 expressed antixenosis against B. tabaci. 'Jackson,' 'P98Y11,' and PI-229358 exhibited the same behavior in the no-choice test. In the multiple-choice test, 'Jackson,' 'P98Y11,' and 'TMG1176 RR' were the least attractive and least used for oviposition. The antixenosis shown by 'Jackson,' 'P98Y11,' and PI-229358 may be related to the characteristics of the trichomes (lower density and inclined). Based on the experiments carried out, 'IAC-17,' 'IAC-19,' 'Jackson,' 'P98Y11,' PI-229358, TMG1176 RR, and UX-2569-159 are considered promising for resistance to B. tabaci biotype B and may be exploited in soybean breeding programs for resistance to insects. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  12. Transcriptomic and proteomic responses of sweetpotato whitefly, Bemisia tabaci, to thiamethoxam.

    PubMed

    Yang, Nina; Xie, Wen; Yang, Xin; Wang, Shaoli; Wu, Qingjun; Li, Rumei; Pan, Huipeng; Liu, Baiming; Shi, Xiaobin; Fang, Yong; Xu, Baoyun; Zhou, Xuguo; Zhang, Youjun

    2013-01-01

    The sweetpotato whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae), is one of the most widely distributed agricultural pests. Although it has developed resistance to many registered insecticides including the neonicotinoid insecticide thiamethoxam, the mechanisms that regulate the resistance are poorly understood. To understand the molecular basis of thiamethoxam resistance, "omics" analyses were carried out to examine differences between resistant and susceptible B. tabaci at both transcriptional and translational levels. A total of 1,338 mRNAs and 52 proteins were differentially expressed between resistant and susceptible B. tabaci. Among them, 11 transcripts had concurrent transcription and translation profiles. KEGG analysis mapped 318 and 35 differentially expressed genes and proteins, respectively, to 160 and 59 pathways (p<0.05). Thiamethoxam treatment activated metabolic pathways (e.g., drug metabolism), in which 118 transcripts were putatively linked to insecticide resistance, including up-regulated glutathione-S-transferase, UDP glucuronosyltransferase, glucosyl/glucuronosyl transferase, and cytochrome P450. Gene Ontology analysis placed these genes and proteins into protein complex, metabolic process, cellular process, signaling, and response to stimulus categories. Quantitative real-time PCR analysis validated "omics" response, and suggested a highly overexpressed P450, CYP6CX1, as a candidate molecular basis for the mechanistic study of thiamethoxam resistance in whiteflies. Finally, enzymatic activity assays showed elevated detoxification activities in the resistant B. tabaci. This study demonstrates the applicability of high-throughput omics tools for identifying molecular candidates related to thiamethoxam resistance in an agricultural important insect pest. In addition, transcriptomic and proteomic analyses provide a solid foundation for future functional investigations into the complex molecular mechanisms governing the neonicotinoid resistance in

  13. Resistance of soybean genotypes to Bemisia tabaci (Genn.) Biotype B (Hemiptera: Aleyrodidae).

    PubMed

    Vieira, S S; Bueno, A F; Boff, M I C; Bueno, R C O F; Hoffman-Campo, C B

    2011-01-01

    The silverleaf whitefly Bemisia tabaci (Genn.) biotype B has become a serious problem for soybean cultivation because it can significantly reduce soybean productivity. The use of soybean cultivars resistant to whitefly attack is an important strategy in an integrated pest management (IPM) program. This study evaluated the preference for oviposition and colonization by B. tabaci biotype B on different soybean genotypes. In the free-choice test, the genotypes studied were 'IAC 17' and 'IAC 19' as the standards for resistance and 'IAC Holambra Stwart' as the standard for susceptibility, as well as BABR01-0492, BABR01-0173, BABR01-1259, BABR01-1576, BABR99-4021HC, BABR99-4021HP, 'Barreiras', 'Conquista', 'Corisco', 'BRS Gralha', PI274454, PI227687, and PI171451. In the no-choice test, the four best genotypes selected in the free-choice test, in addition to the susceptible and resistant standards were evaluated. Our data indicated 'Barreiras' as the most resistant genotype against B. tabaci biotype B. 'BRS Gralha', which was the least attractive to whitefly adults in the free-choice test, did not show resistance to insect attack when they were confined in cages in the no-choice test. Despite the high number of eggs observed, BABR01-1576 and BABR99-4021HC showed a reduced number of nymphs, indicating antibiosis. The genotypes with a high level of resistance can be used as a tool against B. tabaci in IPM or as a source of resistance in plant-breeding programs.

  14. Transcriptomic and Proteomic Responses of Sweetpotato Whitefly, Bemisia tabaci, to Thiamethoxam

    PubMed Central

    Yang, Nina; Xie, Wen; Yang, Xin; Wang, Shaoli; Wu, Qingjun; Li, Rumei; Pan, Huipeng; Liu, Baiming; Shi, Xiaobin; Fang, Yong; Xu, Baoyun; Zhou, Xuguo; Zhang, Youjun

    2013-01-01

    Background The sweetpotato whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae), is one of the most widely distributed agricultural pests. Although it has developed resistance to many registered insecticides including the neonicotinoid insecticide thiamethoxam, the mechanisms that regulate the resistance are poorly understood. To understand the molecular basis of thiamethoxam resistance, “omics” analyses were carried out to examine differences between resistant and susceptible B. tabaci at both transcriptional and translational levels. Results A total of 1,338 mRNAs and 52 proteins were differentially expressed between resistant and susceptible B. tabaci. Among them, 11 transcripts had concurrent transcription and translation profiles. KEGG analysis mapped 318 and 35 differentially expressed genes and proteins, respectively, to 160 and 59 pathways (p<0.05). Thiamethoxam treatment activated metabolic pathways (e.g., drug metabolism), in which 118 transcripts were putatively linked to insecticide resistance, including up-regulated glutathione-S-transferase, UDP glucuronosyltransferase, glucosyl/glucuronosyl transferase, and cytochrome P450. Gene Ontology analysis placed these genes and proteins into protein complex, metabolic process, cellular process, signaling, and response to stimulus categories. Quantitative real-time PCR analysis validated “omics” response, and suggested a highly overexpressed P450, CYP6CX1, as a candidate molecular basis for the mechanistic study of thiamethoxam resistance in whiteflies. Finally, enzymatic activity assays showed elevated detoxification activities in the resistant B. tabaci. Conclusions This study demonstrates the applicability of high-throughput omics tools for identifying molecular candidates related to thiamethoxam resistance in an agricultural important insect pest. In addition, transcriptomic and proteomic analyses provide a solid foundation for future functional investigations into the complex molecular mechanisms

  15. Phylogenetic Relationships among Whiteflies in the Bemisia tabaci (Gennadius) Species Complex from Major Cassava Growing Areas in Kenya.

    PubMed

    Manani, Duke M; Ateka, Elijah M; Nyanjom, Steven R G; Boykin, Laura M

    2017-02-28

    Whiteflies, Bemisia tabaci (Gennadius) are major insect pests that affect many crops such as cassava, tomato, beans, cotton, cucurbits, potato, sweet potato, and ornamental crops. Bemisia tabaci transmits viral diseases, namely cassava mosaic and cassava brown streak diseases, which are the main constraints to cassava production, causing huge losses to many small-scale farmers. The aim of this work was to determine the phylogenetic relationships among Bemisia tabaci species in major cassava growing areas of Kenya. Surveys were carried out between 2013 and 2015 in major cassava growing areas (Western, Nyanza, Eastern, and Coast regions), for cassava mosaic disease (CMD) and cassava brown streak disease (CBSD). Mitochondrial cytochrome oxidase I (mtCOI-DNA) was used to determine the genetic diversity of B. tabaci. Phylogenetic trees were constructed using Bayesian methods to understand the genetic diversity across the study regions. Phylogenetic analysis revealed two B. tabaci species present in Kenya, sub-Saharan Africa 1 and 2 comprising five distinct clades (A-E) with percent sequence similarity ranging from 97.7 % to 99.5%. Clades B, C, D, and E are predominantly distributed in the Western and Nyanza regions of Kenya whereas clade B is dominantly found along the coast, the eastern region, and parts of Nyanza. Our B. tabaci clade A groups with sub-Saharan Africa 2-(SSA2) recorded a percent sequence similarity of 99.5%. In this study, we also report the identification of SSA2 after a 15 year absence in Kenya. The SSA2 species associated with CMD has been found in the Western region of Kenya bordering Uganda. More information is needed to determine if these species are differentially involved in the epidemiology of the cassava viruses.

  16. Phylogenetic Relationships among Whiteflies in the Bemisia tabaci (Gennadius) Species Complex from Major Cassava Growing Areas in Kenya

    PubMed Central

    Manani, Duke M.; Ateka, Elijah M.; Nyanjom, Steven R. G.; Boykin, Laura M.

    2017-01-01

    Whiteflies, Bemisia tabaci (Gennadius) are major insect pests that affect many crops such as cassava, tomato, beans, cotton, cucurbits, potato, sweet potato, and ornamental crops. Bemisia tabaci transmits viral diseases, namely cassava mosaic and cassava brown streak diseases, which are the main constraints to cassava production, causing huge losses to many small-scale farmers. The aim of this work was to determine the phylogenetic relationships among Bemisia tabaci species in major cassava growing areas of Kenya. Surveys were carried out between 2013 and 2015 in major cassava growing areas (Western, Nyanza, Eastern, and Coast regions), for cassava mosaic disease (CMD) and cassava brown streak disease (CBSD). Mitochondrial cytochrome oxidase I (mtCOI-DNA) was used to determine the genetic diversity of B. tabaci. Phylogenetic trees were constructed using Bayesian methods to understand the genetic diversity across the study regions. Phylogenetic analysis revealed two B. tabaci species present in Kenya, sub-Saharan Africa 1 and 2 comprising five distinct clades (A–E) with percent sequence similarity ranging from 97.7 % to 99.5%. Clades B, C, D, and E are predominantly distributed in the Western and Nyanza regions of Kenya whereas clade B is dominantly found along the coast, the eastern region, and parts of Nyanza. Our B. tabaci clade A groups with sub-Saharan Africa 2-(SSA2) recorded a percent sequence similarity of 99.5%. In this study, we also report the identification of SSA2 after a 15 year absence in Kenya. The SSA2 species associated with CMD has been found in the Western region of Kenya bordering Uganda. More information is needed to determine if these species are differentially involved in the epidemiology of the cassava viruses. PMID:28264479

  17. Effect of starvation on vein preference of whitefly (Bemisia tabaci) on chilli as host plant

    NASA Astrophysics Data System (ADS)

    Siti Sakinah, A.; Mohamad Roff M., N.; Idris, A. B.

    2014-09-01

    The whitefly, Bemisia tabaci (Gennadius), is a cosmopolitan pest of horticultural crops. It caused serious damaged to the plants by feeding on plant saps as direct damage and transmit virus as indirect damage. Vein preferences of both female and male whitefly (WF) on chilli plant were recorded using Dinolite, a portable microscope, under laboratory conditions. WF adults of both sexes were starved for 2 and 4 hours before used for observation while no starvation for control individual (treatment). Results showed that both female and male preferred to feed on secondary veins rather than lamina, midrib and vein. From the result of whitefly preferred target site, hopefully this information will help to improve control tactics in WF management.

  18. [Transmission of tomato Venezuela virus by Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), in Maracaibo, Venezuela].

    PubMed

    Romay, Gustavo; Geraud-Pouey, Francis; Chirinos, Dorys T; Morales, Francisco; Herrera, Emilio; Fernández, Carlos; Martínez, Ana K

    2010-01-01

    The biological transmission of Tomato Venezuela virus (ToVEV) by biotype B of the whitefly species Bemisia tabaci (Gennadius) increased (21.7-95.0%), and the time for symptom expression decreased (16-12.6 days) as the number of viruliferous whiteflies allowed access for inoculation to susceptible tomato plants increased from 1 to 20 adults/plant. When acquired only as a nymph, adults of this biotype transmitted the virus to 88.3% of susceptible tomato plants, using 15 viruliferous individuals per test plant, corroborating the circulative nature of the transmission. Disease incidence further increased (up to 100%) when the individuals were allowed to feed again on a virus-infected plant as adults. Leaf area, plant height and dry matter were significantly affected in ToVEV infected tomato plants.

  19. A peptidoglycan recognition protein acts in whitefly (Bemisia tabaci) immunity and involves in Begomovirus acquisition

    PubMed Central

    Wang, Zhi-Zhi; Shi, Min; Huang, Yi-Cun; Wang, Xiao-Wei; Stanley, David; Chen, Xue-Xin

    2016-01-01

    Peptidoglycan recognition proteins (PGRPs) are multifunctional pattern recognition proteins. Here, we report that a PGRP gene, BtPGRP, encodes a PGRP from the whitefly Bemisia tabaci (MEAM1) that binds and kills bacteria in vitro. We analyzed BtPGRP transcriptional profiling, and the distribution of the cognate protein within the midgut. Fungal infection and wasp parasitization induced expression of BtPGRP. Silencing BtPGRP with artificial media amended with dsRNA led to reduced expression of a gene encoding an antimicrobial peptide, B. tabaci c-type lysozyme. Begomovirus infection also led to increased expression of BtPGRP. We propose that BtPGRP has a potential Tomato yellow leaf curl virus (TYLCV) binding site because we detected in vitro interaction between BtPGRP and TYLCV by immunocapture PCR, and recorded the co-localization of TYLCV and BtPGRP in midguts. This work addresses a visible gap in understanding whitefly immunity and provides insight into how the whitefly immunity acts in complex mechanisms of Begomovirus transmission among plants. PMID:27892529

  20. Acyl sugars and whitefly (Bemisia tabaci) resistance in segregating populations of tomato genotypes.

    PubMed

    Dias, D M; Resende, J T V; Marodin, J C; Matos, R; Lustosa, I F; Resende, N C V

    2016-04-07

    The wild tomato, Solanum pennellii, is an important source of resistance genes against tomato pests. This resistance is due to the presence of acyl sugars (AS), which are allelochemicals that have negative effects on arthropod pests. There are no commercially available tomato cultivars that exhibit significant levels of resistance to arthropod pests. Therefore, this study evaluated resistance to whitefly (Bemisia tabaci) in F2 and F2RC1 tomato genotypes with high AS levels from a cross between Solanum lycopersicum 'Redenção' and the S. pennellii accession, LA-716. Plants were exposed to B. tabaci biotype B at the pre-flowering stage. In both generations, there were significant, negative correlations between AS content and oviposition preference and nymph development. Whitefly exhibited a lower preference for oviposition and produced fewer nymphs in genotypes with high AS levels and the wild parent S. pennellii than in the low AS-level genotypes and Redenção cultivar, demonstrating that the breeding program was effective in transferring resistance to the F2 and F2RC1 generations. RVTA-2010-pl#31 and RVTA-2010-pl#94 in the F2 population are promising genotypes that produced materials with high AS levels in the F2RC1 generation (RVTA-2010-31-pl#177 and RVTA-2010-94-pl#381).

  1. Quantitative resistance against Bemisia tabaci in Solanum pennellii: Genetics and metabolomics.

    PubMed

    van den Oever-van den Elsen, Floor; Lucatti, Alejandro F; van Heusden, Sjaak; Broekgaarden, Colette; Mumm, Roland; Dicke, Marcel; Vosman, Ben

    2016-04-01

    The whitefly Bemisia tabaci is a serious threat in tomato cultivation worldwide as all varieties grown today are highly susceptible to this devastating herbivorous insect. Many accessions of the tomato wild relative Solanum pennellii show a high resistance towards B. tabaci. A mapping approach was used to elucidate the genetic background of whitefly-resistance related traits and associated biochemical traits in this species. Minor quantitative trait loci (QTLs) for whitefly adult survival (AS) and oviposition rate (OR) were identified and some were confirmed in an F2 BC1 population, where they showed increased percentages of explained variance (more than 30%). Bulked segregant analyses on pools of whitefly-resistant and -susceptible F2 plants enabled the identification of metabolites that correlate either with resistance or susceptibility. Genetic mapping of these metabolites showed that a large number of them co-localize with whitefly-resistance QTLs. Some of these whitefly-resistance QTLs are hotspots for metabolite QTLs. Although a large number of metabolite QTLs correlated to whitefly resistance or susceptibility, most of them are yet unknown compounds and further studies are needed to identify the metabolic pathways and genes involved. The results indicate a direct genetic correlation between biochemical-based resistance characteristics and reduced whitefly incidence in S. pennellii.

  2. Biological Invasions of Geminiviruses: Case Study of TYLCV and Bemisia tabaci in Reunion Island

    PubMed Central

    Péréfarres, Frédéric; Thierry, Magali; Becker, Nathalie; Lefeuvre, Pierre; Reynaud, Bernard; Delatte, Hélène; Lett, Jean-Michel

    2012-01-01

    In the last 20 years, molecular ecology approaches have proven to be extremely useful to identify and assess factors associated with viral emerging diseases, particularly in economically and socially important tropical crops such as maize (maize streak disease) and cassava (cassava mosaic disease). Molecular ecology approaches were applied in Reunion Island to analyze the epidemic of tomato yellow leaf curl disease, which has been affecting the island since the end of the 1990s. Before the invasive biotype B (currently known as Middle East-Asia Minor 1 cryptic species) of Bemisia tabaci spread across the world, Reunion Island (South West Indian Ocean) only hosted an indigenous biotype of B. tabaci, Ms (currently known as Indian Ocean cryptic species). Wild hybrids between invasive and indigenous species were subsequently characterized over multiple generations. Endosymbiont analysis of the hybrid population indicated that matings were non-random. Similarly, while no indigenous begomoviruses have ever been reported on Reunion Island, the two main strains of one of the most damaging and emerging plant viruses in the world, the Mild and Israel strains of the Tomato yellow leaf curl virus (TYLCV-Mld and TYLCV-IL), were introduced in 1997 and 2004 respectively. While these introductions extensively modified the agricultural landscape of Reunion Island, they also provided an invaluable opportunity to study the ecological and genetic mechanisms involved in biological invasion and competition. PMID:23235470

  3. Biological invasions of geminiviruses: case study of TYLCV and Bemisia tabaci in Reunion Island.

    PubMed

    Péréfarres, Frédéric; Thierry, Magali; Becker, Nathalie; Lefeuvre, Pierre; Reynaud, Bernard; Delatte, Hélène; Lett, Jean-Michel

    2012-12-12

    In the last 20 years, molecular ecology approaches have proven to be extremely useful to identify and assess factors associated with viral emerging diseases, particularly in economically and socially important tropical crops such as maize (maize streak disease) and cassava (cassava mosaic disease). Molecular ecology approaches were applied in Reunion Island to analyze the epidemic of tomato yellow leaf curl disease, which has been affecting the island since the end of the 1990s. Before the invasive biotype B (currently known as Middle East-Asia Minor 1 cryptic species) of Bemisia tabaci spread across the world, Reunion Island (South West Indian Ocean) only hosted an indigenous biotype of B. tabaci, Ms (currently known as Indian Ocean cryptic species). Wild hybrids between invasive and indigenous species were subsequently characterized over multiple generations. Endosymbiont analysis of the hybrid population indicated that matings were non-random. Similarly, while no indigenous begomoviruses have ever been reported on Reunion Island, the two main strains of one of the most damaging and emerging plant viruses in the world, the Mild and Israel strains of the Tomato yellow leaf curl virus (TYLCV-Mld and TYLCV-IL), were introduced in 1997 and 2004 respectively. While these introductions extensively modified the agricultural landscape of Reunion Island, they also provided an invaluable opportunity to study the ecological and genetic mechanisms involved in biological invasion and competition.

  4. Oral toxicity of Photorhabdus culture media on gene expression of the adult sweetpotato whitefly, Bemisia tabaci.

    PubMed

    Shrestha, Yam Kumar; Lee, Kyeong-Yeoll

    2012-01-01

    The oral toxicity of culture media of the symbiotic bacteria, Photorhabdus temperata, mutually associated with entomopathogenic nematode Heterorhabditis megidis and Photorhabdus luminescens ssp. laumondii (TT01) mutually associated with Heterorhabditis bacteriophora, were investigated in the adults of Bemisia tabaci. The oral ingestion of sucrose diet solutions (20%) containing bacteria-free supernatant of the culture media from symbiotic bacteria gradually increased mortalities and was completely lethal at 60 h after the treatments, whereas the mortalities of the controls, sucrose solutions with or without media that uncultured with bacteria, were less than 17% up to 84 h of incubation. The effects of oral ingestion of symbiont culture media were demonstrated on the expression rates of several genes of B. tabaci using quantitative real-time RT-PCR analysis. Genes associated with immunity (knottin) and nervous system (acetylcholine receptor, acetylcholine esterase and sodium channel) were up-regulated while genes involved in metabolism (cytochromep450 and carboxylesterase) were down-regulated, but genes involved in development (ecdysone receptor), reproduction (vitellogenin) and stress (hsp70, hsp90 and shsp) did not change transcription rates. Our results provide information for the understanding of the mechanism of symbiont pathogenic factors for the manipulation of host physiology at the transcription level. Copyright © 2011 Elsevier Inc. All rights reserved.

  5. The Salicylic Acid-Mediated Release of Plant Volatiles Affects the Host Choice of Bemisia tabaci

    PubMed Central

    Shi, Xiaobin; Chen, Gong; Tian, Lixia; Peng, Zhengke; Xie, Wen; Wu, Qingjun; Wang, Shaoli; Zhou, Xuguo; Zhang, Youjun

    2016-01-01

    The whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) causes serious crop losses worldwide by transmitting viruses. We have previously shown that salicylic acid (SA)-related plant defenses directly affect whiteflies. In this study, we applied exogenous SA to tomato plants in order to investigate the interaction between SA-induced plant volatiles and nonviruliferous B. tabaci B and Q or B- and Q-carrying tomato yellow leaf curl virus (TYLCV). The results showed that exogenous SA caused plants to repel nonviruliferous whiteflies, but the effect was reduced when the SA concentration was low and when the whiteflies were viruliferous. Exogenous SA increased the number and quantity of plant volatiles—especially the quantity of methyl salicylate and δ-limonene. In Y-tube olfactometer assays, methyl salicylate and δ-limonene repelled the whiteflies, but the repellency was reduced for viruliferous Q. We suggest that the release of plant volatiles as mediated by SA affects the interaction between whiteflies, plants, and viruses. Further studies are needed to determine why viruliferous Q is less sensitive than nonviruliferous Q to repellent plant volatiles. PMID:27376280

  6. Thermal effect on the biology and life tables of Bemisia tabaci Gennadius (Homoptera: Aleyrodidae).

    PubMed

    Sohani, N Zandi; Shishehbor, P; Kocheili, F

    2007-11-15

    The life history and life table of Bemisia tabaci Gennadius on cucumber was studied under laboratory conditions at 20, 25 and 30 degrees C. The overall developmental time varied from 34.8 days at 20 degrees C to 14.1 days at 30 degrees C. Immature mortality decreased from 45.8 to 17.3% with increasing temperature. The threshold temperatures of egg, 1st, 2nd, 3rd and 4th nymphal stage and a generation were 14.72, 14.36, 10.18, 11.40, 14.36 and 13.07 degrees C whereas the degree-day requirement at each stage was 64.44, 42.39, 49.19, 33.19, 35.46 and 229.52 DD, respectively. Female longevity ranged from 16.8-34.1 days. Mean total fecundity ranged from 150-263 eggs/female. Mean daily fecundity ranged from 4.2-12.7 eggs/female, increasing with increasing temperature. Values for r(m) varied from 0.066 to 0.191 being least at 20 degrees C and greatest at 30 degrees C. Generation times decreased from 43 to 19 days with increasing temperature. The results indicate that B. tabaci is well adapted to high temperatures and may extend its distribution if mean world temperatures increase as a result of global warming.

  7. Challenges with managing insecticide resistance in agricultural pests, exemplisfied by the whitefly Bemisia tabaci

    PubMed Central

    Denholm, I.

    1998-01-01

    For many key agricultural pests, successful management of insecticide resistance depends not only on modifying the way that insecticides are deployed, but also on reducing the total number of treatments applied. Both approaches benefit from a knowledge of the biological characteristics of pests that promote or may retard the development of resistance. For the whitefly Bemisia tabaci (Gennadius), these factors include a haplodiploid breeding system that encourages the rapid selection and fixation of resistance genes, its breeding cycle on a succession of treated or untreated hosts, and its occurrence on and dispersal from high-value crops in greenhouses and glasshouses. These factors, in conjunction with often intensive insecticide use, have led to severe and widespread resistance that now affects several novel as well as conventional control agents. Resistance-management strategies implemented on cotton in Israel, and subsequently in south-western USA, have nonetheless so far succeeded in arresting the resistance treadmill in B. tabaci through a combination of increased chemical diversity, voluntary or mandatory restrictions on the use of key insecticides, and careful integration of chemical control with other pest-management options. In both countries, the most significant achievement has been a dramatic reduction in the number of insecticide treatments applied against whiteflies on cotton, increasing the prospect of sustained use of existing and future insecticides.

  8. Foraging behavior and prey interactions by a guild of predators on various lifestages of Bemisia tabaci

    PubMed Central

    Hagler, James R.; Jackson, Charles G.; Isaacs, Rufus; Machtley, Scott A.

    2004-01-01

    The sweetpotato whitefly, Bemisia tabaci (Gennadius) is fed on by a wide variety of generalist predators, but there is little information on these predator-prey interactions. A laboratory investigation was conducted to quantify the foraging behavior of the adults of five common whitefly predators presented with a surfeit of whitefly eggs, nymphs, and adults. The beetles, Hippodamia convergens Guérin-Méneville and Collops vittatus (Say) fed mostly on whitefly eggs, but readily and rapidly preyed on all of the whitefly lifestages. The true bugs, Geocoris punctipes (Say) and Orius tristicolor (Say) preyed almost exclusively on adult whiteflies, while Lygus hesperus Knight preyed almost exclusively on nymphs. The true bugs had much longer prey handling times than the beetles and spent much more of their time feeding (35–42%) than the beetles (6–7%). These results indicate that generalist predators vary significantly in their interaction with this host, and that foraging behavior should be considered during development of a predator-based biological control program for B. tabaci. Abbreviation: ELISA enzyme-linked immunosorbent assay PMID:15861217

  9. Identification of biochemical markers linked to neonicotinoid cross resistance in Bemisia tabaci (Hemiptera: Aleyrodidae).

    PubMed

    Rauch, Natascha; Nauen, Ralf

    2003-12-01

    The whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae), is a serious pest in many cropping systems world-wide and occurs in different biotypes. The most widespread one is the B-type, whereas the Q-biotype is nowadays still mostly restricted to Southern Spain. Neonicotinoid cross-resistance is known at a high level in Q-types from Spain and individual samples collected in Italy and Germany. Now we detected for the first time high neonicotinoid cross-resistance in a B-type from Israel. Target site resistance to imidacloprid using [(3)H]imidacloprid in nicotinic acetylcholine receptor (nAChR) binding assays could not be detected in any of these highly resistant strains. The impact of metabolizing enzymes such as esterases, glutathione S-transferases, and cytochrome P450-dependent monooxygenases in neonicotinoid resistance was studied biochemically with artificial substrates. Monooxygenase activity was increased 2-3-fold in moderately resistant strains (RF approximately 30) and even 5-6-fold in highly resistant strains (RF approximately 1,000). Only monooxygenase activity correlated with imidacloprid, thiamethoxam and acetamiprid resistance and, therefore, monooxygenases seem to be the only enzyme system responsible for neonicotinoid resistance in B. tabaci Q- and B-types. The oxidative degradation of imidacloprid in resistant Q-type strains could be confirmed by metabolism studies of [(14)C]imidacloprid in vivo. Five-hydroxy-imidacloprid could be detected as the only main metabolite. The insecticidal activity and binding affinity to nAChR of this compound was 10 times lower than imidacloprid itself in B. tabaci. Copyright 2003 Wiley-Liss, Inc.

  10. Small RNAs from Bemisia tabaci Are Transferred to Solanum lycopersicum Phloem during Feeding

    PubMed Central

    van Kleeff, Paula J. M.; Galland, Marc; Schuurink, Robert C.; Bleeker, Petra M.

    2016-01-01

    The phloem-feeding whitefly Bemisia tabaci is a serious pest to a broad range of host plants, including many economically important crops such as tomato. These insects serve as a vector for various devastating plant viruses. It is known that whiteflies are capable of manipulating host-defense responses, potentially mediated by effector molecules in the whitefly saliva. We hypothesized that, beside putative effector proteins, small RNAs (sRNA) are delivered by B. tabaci into the phloem, where they may play a role in manipulating host plant defenses. There is already evidence to suggest that sRNAs can mediate the host-pathogen dialogue. It has been shown that Botrytis cinerea, the causal agent of gray mold disease, takes advantage of the plant sRNA machinery to selectively silence host genes involved in defense signaling. Here we identified sRNAs originating from B. tabaci in the phloem of tomato plants on which they are feeding. sRNAs were isolated and sequenced from tomato phloem of whitefly-infested and control plants as well as from the nymphs themselves, control leaflets, and from the infested leaflets. Using stem-loop RT-PCR, three whitefly sRNAs have been verified to be present in whitefly-infested leaflets that were also present in the whitefly-infested phloem sample. Our results show that whitefly sRNAs are indeed present in tomato tissues upon feeding, and they appear to be mobile in the phloem. Their role in the host-insect interaction can now be investigated. PMID:27933079

  11. Monitoring changes in Bemisia tabaci (Hemiptera: Aleyrodidae) susceptibility to neonicotinoid insecticides in Arizona and California.

    PubMed

    Castle, S J; Prabhaker, N

    2013-06-01

    Bemisia tabaci (Gennadius) biotype B is a highly prolific and polyphagous whitefly that established in much of North America during the 1980s. Neonicotinoid insecticides have been fundamental in regaining control over outbreak populations of B. tabaci, but resistance threatens their sustainability. Susceptibility of B. tabaci in the southwestern United States to four neonicotinoid insecticides varied considerably across populations within each year over a 3 yr period. Using a variability ratio of highest LC50 to lowest LC50 in field-collected whitefly adults from Arizona and California, the ranges of LC50(s) across all tests within compounds were highest to imidacloprid and lowest to thiamethoxam. Patterns of susceptibility were similar among all four neonicotinoid insecticides, but the greater variability in responses to imidacloprid and significantly higher LC50(s) attained indicated higher resistance levels to imidacloprid in all field populations. Further evidence of differential toxicities of neonicotinoids was observed in multiple tests of dinotefuran against imidacloprid-resistant lab strains that yielded significant differences in the LC50(s) of dinotefuran and imidacloprid in simultaneous bioassays. To test the possibility that resistance expression in field-collected insects was sometimes masked by stressful conditions, field strains cultured in a greenhouse without insecticide exposure produced significantly higher LC50(s) to all neonicotinoids compared with LC50(s) attained directly from the field. In harsh climates such as the American southwest, resistance expression in field-collected test insects may be strongly influenced by environmental stresses such as high temperatures, overcrowding, and declining host plant quality.

  12. Glutathione S-transferases are involved in thiamethoxam resistance in the field whitefly Bemisia tabaci Q (Hemiptera: Aleyrodidae).

    PubMed

    Yang, Xin; He, Chao; Xie, Wen; Liu, Yating; Xia, Jixing; Yang, Zezong; Guo, Litao; Wen, Yanan; Wang, Shaoli; Wu, Qingjun; Yang, Fengshan; Zhou, Xiaomao; Zhang, Youjun

    2016-11-01

    The whitefly, Bemisia tabaci, has developed a high level of resistance to thiamethoxam, a second generation neonicotinoid insecticide that has been widely used to control this pest. In this study, we assessed the level of cross-resistance, the activities of detoxifying enzymes, and the expression profiles of 23 glutathione S-transferase (GST) genes in a thiamethoxam-resistant ant and -susceptible strain of Bemisia tabaci Q. The thiamethoxam-resistant strain showed a moderate level of cross-resistance to another nicotinoid insecticide imidacloprid, a low level of cross-resistance to acetamiprid and nitenpyram, and no significant cross-resistance to abamectin and bifenthrin. Among detoxifying enzymes, only GSTs had significantly higher activity in the resistant strain than in the susceptible strain. Seven of 23 GST genes were over-expressed in the resistant strain relative to the susceptible strain. Using the technology of RNA interference to knockdown a GST gene (GST14), the results showed that silencing GST14 increased the mortality of whiteflies to thiamethoxam in Bemisia tabaci. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Global Population Structure of a Worldwide Pest and Virus Vector: Genetic Diversity and Population History of the Bemisia tabaci Sibling Species Group

    PubMed Central

    2016-01-01

    The whitefly Bemisia tabaci sibling species (sibsp.) group comprises morphologically indiscernible lineages of well-known exemplars referred to as biotypes. It is distributed throughout tropical and subtropical latitudes and includes the contemporary invasive haplotypes, termed B and Q. Several well-studied B. tabaci biotypes exhibit ecological and biological diversity, however, most members are poorly studied or completely uncharacterized. Genetic studies have revealed substantial diversity within the group based on a fragment of the mitochondrial cytochrome oxidase I (mtCOI) sequence (haplotypes), with other tested markers being less useful for deep phylogenetic comparisons. The view of global relationships within the B. tabaci sibsp. group is largely derived from this single marker, making assessment of gene flow and genetic structure difficult at the population level. Here, the population structure was explored for B. tabaci in a global context using nuclear data from variable microsatellite markers. Worldwide collections were examined representing most of the available diversity, including known monophagous, polyphagous, invasive, and indigenous haplotypes. Well-characterized biotypes and other related geographic lineages discovered represented highly differentiated genetic clusters with little or no evidence of gene flow. The invasive B and Q biotypes exhibited moderate to high levels of genetic diversity, suggesting that they stemmed from large founding populations that have maintained ancestral variation, despite homogenizing effects, possibly due to human-mediated among-population gene flow. Results of the microsatellite analyses are in general agreement with published mtCOI phylogenies; however, notable conflicts exist between the nuclear and mitochondrial relationships, highlighting the need for a multifaceted approach to delineate the evolutionary history of the group. This study supports the hypothesis that the extant B. tabaci sibsp. group contains

  14. Phylogeographical structure in mitochondrial DNA of whitefly, Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) in southern India and Southeast Asia.

    PubMed

    Ram Kumar, Nikhil; Chang, Jian-Cheng; Narayanan, Manikanda Boopathi; Ramasamy, Srinivasan

    2017-09-01

    South and Southeast Asia endure high vegetable production losses due to begomovirus diseases mainly transmitted by the insect vector, whitefly (Bemisia tabaci). Control over the spread of virus infection can be achieved through a better understanding of genetic diversity among B. tabaci. A total of 64 populations of B. tabaci collected from Tamil Nadu (India), Vietnam, Thailand, and Indonesia were investigated based on mitochondrial cytochrome c oxidase I (coxI) sequences. Populations from Tamil Nadu are distributed into three clades (Asia I, Asia II 7, and Asia II 8), whereas Indonesian populations settle along with Asia I population of India in the phylogenetic tree. Vietnam populations align with the Middle East-Asia Minor 1 (MEAM1) clade, and interestingly MEAM1 invades northern Vietnam quite recently. Samples from Thailand made a unique clade between the outgroup and the remaining B. tabaci, representing the possibility of a new subspecies. AMOVA analysis among populations from various districts in Tamil Nadu exhibits significant differences, which represent each district's individuality. This study proves that the use of coxI as a marker for molecular identification of B. tabaci can provide a better estimate of diversity. We provide important clues for developing insight into the genetic structure of B. tabaci, and suggest strategies for control.

  15. Identification and expression profile analysis of odorant binding protein and chemosensory protein genes in Bemisia tabaci MED by head transcriptome

    PubMed Central

    Zhang, Wei; Zhang, Xiaoman; Qu, Cheng; Tetreau, Guillaume; Sun, Lujuan; Zhou, Jingjiang

    2017-01-01

    Odorant binding proteins (OBPs) and chemosensory proteins (CSPs) of arthropods are thought to be involved in chemical recognition which regulates pivotal behaviors including host choice, copulation and reproduction. In insects, OBPs and CSPs located mainly in the antenna but they have not been systematically characterized yet in Bemisia tabaci which is a cryptic species complex and could damage more than 600 plant species. In this study, among the 106,893 transcripts in the head assembly, 8 OBPs and 13 CSPs were identified in B. tabaci MED based on head transcriptomes of adults. Phylogenetic analyses were conducted to investigate the relationships of B. tabaci OBPs and CSPs with those from several other important Hemipteran species, and the motif-patterns between Hemiptera OBPs and CSPs were also compared by MEME. The expression profiles of the OBP and CSP genes in different tissues of B. tabaci MED adults were analyzed by real-time qPCR. Seven out of the 8 OBPs found in B. tabaci MED were highly expressed in the head. Conversely, only 4 CSPs were enriched in the head, while the other nine CSPs were specifically expressed in other tissues. Our findings pave the way for future research on chemical recognition of B. tabaci at the molecular level. PMID:28166541

  16. Trade-offs between survival, longevity, and reproduction, and variation of survival tolerance in Mediterranean Bemisia tabaci after temperature stress.

    PubMed

    Lü, Zhi-Chuang; Wang, Yan-Min; Zhu, Shao-Guang; Yu, Hao; Guo, Jian-Ying; Wan, Fang-Hao

    2014-01-01

    The invasive Mediterranean Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) has emerged as one of the most common agricultural pests in the world. In the present study, we examined the cross-tolerance, fitness costs, and benefits of thermal tolerance and the variation in the responses of life history traits after heat-shock selection. The results showed that survival and longevity of Mediterranean B. tabaci were decreased significantly after direct or cross temperature stress and that the number of eggs per female was not reduced significantly. Furthermore, heat-shock selection dramatically increased the survival of Mediterranean B. tabaci within two generations, and it did not significantly affect the egg number per female within five generations. These results indicated that there was a trade-off between survival, longevity, and reproduction in Mediterranean B. tabaci after temperature stress. The improvement in reproduction was costly in terms of decreased survival and longevity, and there was a fitness consequence to temperature stress. In addition, heat tolerance in Mediterranean B. tabaci increased substantially after selection by heat shock, indicating a considerable variation for survival tolerance in this species. This information could help us better understand the thermal biology of Mediterranean B. tabaci within the context of climate change. This is an open access paper. We use the Creative Commons Attribution 3.0 license that permits unrestricted use, provided that the paper is properly attributed.

  17. Trade-Offs between Survival, Longevity, and Reproduction, and Variation of Survival Tolerance in Mediterranean Bemisia tabaci after Temperature Stress

    PubMed Central

    Lü, Zhi-Chuang; Wang, Yan-Min; Zhu, Shao-Guang; Yu, Hao; Guo, Jian-Ying; Wan, Fang-Hao

    2014-01-01

    The invasive Mediterranean Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) has emerged as one of the most common agricultural pests in the world. In the present study, we examined the cross-tolerance, fitness costs, and benefits of thermal tolerance and the variation in the responses of life history traits after heat-shock selection. The results showed that survival and longevity of Mediterranean B. tabaci were decreased significantly after direct or cross temperature stress and that the number of eggs per female was not reduced significantly. Furthermore, heat-shock selection dramatically increased the survival of Mediterranean B. tabaci within two generations, and it did not significantly affect the egg number per female within five generations. These results indicated that there was a trade-off between survival, longevity, and reproduction in Mediterranean B. tabaci after temperature stress. The improvement in reproduction was costly in terms of decreased survival and longevity, and there was a fitness consequence to temperature stress. In addition, heat tolerance in Mediterranean B. tabaci increased substantially after selection by heat shock, indicating a considerable variation for survival tolerance in this species. This information could help us better understand the thermal biology of Mediterranean B. tabaci within the context of climate change. PMID:25368068

  18. [Effects of calcium fertilizer on the development, survival, and feeding of B-biotype Bemisia tabaci on Euphorbia pulcherrima].

    PubMed

    Huang, Jun; Zhang, Juan; Yu, Yong-Ming; Liu, Jian-Xin; Li, Ming-Jiang; Zhu, Kai-Yuan

    2012-09-01

    This paper studied the development, survival, and feeding of B-biotype Bemisia tabaci on Euphorbia pulcherrima under the conditions of 26 +/- 1 degrees C and 60% - 80% relative humidity after applying calcium fertilizer, taking applying fresh water as the control. There existed significant differences in the developmental duration of B. tabaci between treatment applying calcium fertilizer and the control. After applying calcium fertilizer, the egg stage of B. tabaci shortened significantly, and the development from egg to adult took 20.18 days (for the control, it took 18.72 days). However, there were no significant differences in the survival rates of B. tabaci at different development stages between the two treatments. The feeding of B. tabaci on E. pulcherrima induced the plant leaf chlorophyll fluorescence parameters changed, i. e., the photochemical efficiency (Fv/Fm), photochemical quenching coefficient (q(p)), light use efficiency (alpha), maximum photosynthesis rate (rETRmax), and tolerance to light (I(k)) decreased significantly, while the non-photochemical quenching coefficient (NPQ) had a significant increase. After applying calcium fertilizer, the plant leaf photoinhibition parameter (beta), rETRmax, and I(k) had less difference with th e control. The nail polish blot observation on the lower epidermis structure of plant leaf showed that calcium fertilizer could effectively compensate the decrease in the photosynthesis of E. pulcherrima damaged by B-biotype B. tabaci.

  19. Insecticidal Activity of Some Reducing Sugars Against the Sweet Potato Whitefly, Bemisia tabaci, Biotype B

    PubMed Central

    Hu, Jing S.; Gelman, Dale B.; Salvucci, Michael E.; Chen, Yan P.; Blackburn, Michael B.

    2010-01-01

    The effects of 16 sugars (arabinose, cellobiose, fructose, galactose, gentiobiose, glucose, inositol, lactose, maltose, mannitol (a sugar alcohol), mannose, melibiose, ribose, sorbitol, trehalose, and xylose) on sweet potato whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) survival were determined using in vitro bioassays. Of these sugars, arabinose, mannose, ribose, and xylose were strongly inhibitory to both nymphal and adult survival. When 10% mannose was added to the nymphal diet, 10.5%, 1.0%, and 0% developed to the 2nd, 3rd, and 4th instars, respectively. When 10% arabinose was added, 10.8% and 0% of the nymphs molted to the 2nd and 3rd instars, respectively. Addition of 10% xylose or ribose completely terminated B. tabaci development, preventing the molt to the 2nd instar. With decreasing sugar concentrations the inhibitory effect was significantly reduced. In tests using adults, arabinose, galactose, inositol, lactose, maltose, mannitol, mannose, melibiose, ribose, sorbitol, trehalose, and xylose significantly reduced mean day survival. Mortality rates were highest when arabinose, mannitol, mannose, ribose, or xylose was added to the diet. Mean day survival was less than 2 days when adults were fed on diet containing 10% of any one of these five sugars. When lower concentrations of sugars were used there was a decrease in mortality. Mode of action studies revealed that toxicity was not due to the inhibition of alpha glucosidase (converts sucrose to glucose and fructose) and/or trehalulose synthase (converts sucrose to trehalulose) activity. The result of agarose gel electrophoresis of RT-PCR products of bacterial endosymbionts amplified from RNA isolated from whiteflies fed with 10% arabinose, mannose, or xylose indicated that the concentration of endosymbionts in mycetomes was not affected by the toxic sugars. Experiments in which B. tabaci were fed on diets that contained radio-labeled sucrose, methionine or inulin and one or none (control) of

  20. Insecticidal activity of some reducing sugars against the sweet potato whitefly, Bemisia tabaci, Biotype B.

    PubMed

    Hu, Jing S; Gelman, Dale B; Salvucci, Michael E; Chen, Yan P; Blackburn, Michael B

    2010-01-01

    The effects of 16 sugars (arabinose, cellobiose, fructose, galactose, gentiobiose, glucose, inositol, lactose, maltose, mannitol (a sugar alcohol), mannose, melibiose, ribose, sorbitol, trehalose, and xylose) on sweet potato whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) survival were determined using in vitro bioassays. Of these sugars, arabinose, mannose, ribose, and xylose were strongly inhibitory to both nymphal and adult survival. When 10% mannose was added to the nymphal diet, 10.5%, 1.0%, and 0% developed to the 2nd, 3rd, and 4th instars, respectively. When 10% arabinose was added, 10.8% and 0% of the nymphs molted to the 2nd and 3rd instars, respectively. Addition of 10% xylose or ribose completely terminated B. tabaci development, preventing the molt to the 2(nd) instar. With decreasing sugar concentrations the inhibitory effect was significantly reduced. In tests using adults, arabinose, galactose, inositol, lactose, maltose, mannitol, mannose, melibiose, ribose, sorbitol, trehalose, and xylose significantly reduced mean day survival. Mortality rates were highest when arabinose, mannitol, mannose, ribose, or xylose was added to the diet. Mean day survival was less than 2 days when adults were fed on diet containing 10% of any one of these five sugars. When lower concentrations of sugars were used there was a decrease in mortality. Mode of action studies revealed that toxicity was not due to the inhibition of alpha glucosidase (converts sucrose to glucose and fructose) and/or trehalulose synthase (converts sucrose to trehalulose) activity. The result of agarose gel electrophoresis of RT-PCR products of bacterial endosymbionts amplified from RNA isolated from whiteflies fed with 10% arabinose, mannose, or xylose indicated that the concentration of endosymbionts in mycetomes was not affected by the toxic sugars. Experiments in which B. tabaci were fed on diets that contained radio-labeled sucrose, methionine or inulin and one or none (control

  1. Replication of Tomato Yellow Leaf Curl Virus in Its Whitefly Vector, Bemisia tabaci.

    PubMed

    Pakkianathan, Britto Cathrin; Kontsedalov, Svetlana; Lebedev, Galina; Mahadav, Assaf; Zeidan, Muhammad; Czosnek, Henryk; Ghanim, Murad

    2015-10-01

    Tomato yellow leaf curl virus (TYLCV) is a begomovirus transmitted exclusively by the whitefly Bemisia tabaci in a persistent, circulative manner. Replication of TYLCV in its vector remains controversial, and thus far, the virus has been considered to be nonpropagative. Following 8 h of acquisition on TYLCV-infected tomato plants or purified virions and then transfer to non-TYLCV-host cotton plants, the amounts of virus inside whitefly adults significantly increased (>2-fold) during the first few days and then continuously decreased, as measured by the amounts of genes on both virus DNA strands. Reported alterations in insect immune and defense responses upon virus retention led us to hypothesize a role for the immune response in suppressing virus replication. After virus acquisition, stress conditions were imposed on whiteflies, and the levels of three viral gene sequences were measured over time. When whiteflies were exposed to TYLCV and treatment with two different pesticides, the virus levels continuously increased. Upon exposure to heat stress, the virus levels gradually decreased, without any initial accumulation. Switching of whiteflies between pesticide, heat stress, and control treatments caused fluctuating increases and decreases in virus levels. Fluorescence in situ hybridization analysis confirmed these results and showed virus signals inside midgut epithelial cell nuclei. Combining the pesticide and heat treatments with virus acquisition had significant effects on fecundity. Altogether, our results demonstrate for the first time that a single-stranded DNA plant virus can replicate in its hemipteran vector. Plant viruses in agricultural crops are of great concern worldwide. Many of them are transmitted from infected to healthy plants by insects. Persistently transmitted viruses often have a complex association with their vectors; however, most are believed not to replicate within these vectors. Such replication is important, as it contributes to the

  2. Insights into the transcriptomics of polyphagy: Bemisia tabaci adaptability to phenylpropanoids involves coordinated expression of defense and metabolic genes.

    PubMed

    Alon, Michal; Elbaz, Moshe; Ben-Zvi, Michal Moyal; Feldmesser, Ester; Vainstein, Alexander; Morin, Shai

    2012-04-01

    The whitefly Bemisia tabaci is a major generalist agricultural pest of field and horticultural crops world-wide. Despite its importance, the molecular bases of defense mechanisms in B. tabaci against major plant secondary defense compounds, such as the phenylpropanoids, remain unknown. Our experimental system utilized transgenic Nicotiana tabacum plants constitutively expressing the PAP1/AtMYB75 transcription factor which activates relatively specifically the phenylpropanoid/flavonoids biosynthetic pathway. Our study used suppression subtractive hybridization (SSH) and cDNA microarray approaches to compare gene expression between B. tabaci adults subjected to wild-type or transgenic plants for 6 h. A total of 2880 clones from the SSH libraries were sequenced. Both the SSH and cDNA microarray analyses indicated a complex interaction between B. tabaci and secondary defense metabolites produced by the phenylpropanoids/flavonoids pathway, involving enhanced expression of detoxification, immunity, oxidative stress and general stress related genes as well as general metabolism and ribosomal genes. Quantitative real-time PCR revealed significant changes in the expression of several of these genes in response to feeding on artificial diet containing the flavonoids quercetin. The elevated transcriptional activity was not accompanied by reduced reproductive performance, indicating high adaptability of B. tabaci to this large group of plant secondary defense metabolites. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Two cytochrome P450 genes are involved in imidacloprid resistance in field populations of the whitefly, Bemisia tabaci, in China.

    PubMed

    Yang, Xin; Xie, Wen; Wang, Shao-li; Wu, Qing-jun; Pan, Hui-peng; Li, Ru-mei; Yang, Ni-na; Liu, Bai-ming; Xu, Bao-yun; Zhou, Xiaomao; Zhang, You-jun

    2013-11-01

    The sweet potato whitefly, Bemisia tabaci (Gennadius) (Hemiptera:Aleyrodidae), is an invasive and damaging pest of field crops worldwide. The neonicotinoid insecticide imidacloprid has been widely used to control this pest. We assessed the species composition (B vs. Q), imidacloprid resistance, and association between imidacloprid resistance and the expression of five P450 genes for 14-17 B. tabaci populations in 12 provinces in China. Fifteen of 17 populations contained only B. tabaci Q, and two populations contained both B and Q. Seven of 17 populations exhibited moderate to high resistance to imidacloprid, and eight populations exhibited low resistance to imidacloprid, compared with the most susceptible field WHHB population. In a study of 14 of the populations, resistance level was correlated with the expression of the P450 genes CYP6CM1 and CYP4C64 but not with the expression of CYP6CX1, CYP6CX4, or CYP6DZ7. This study indicates that B. tabaci Q has a wider distribution in China than previously reported. Resistance to imidacloprid in field populations of B. tabaci is associated with the increased expression of two cytochrome P450 genes (CYP6CM1 and CYP4C64).

  4. Non-invasive delivery of dsGST is lethal to the sweet potato whitefly, Bemisia tabaci (G.) (Hemiptera: Aleyrodidae).

    PubMed

    Asokan, R; Rebijith, K B; Roopa, H K; Kumar, N K Krishna

    2015-02-01

    The sweet potato whitefly, Bemisia tabaci (G.) biotype B (Hemiptera: Aleyrodidae), is one of the most economically important pest, by being a dreaded vector of Geminiviruses, and also causes direct damage to the crops by sucking phloem sap. Glutathione S-transferase (GST) is a large family of multifunctional enzymes that play pivotal roles in the detoxification of secondary allelochemical produced by the host plants and in insecticide resistance, thus regulates insect growth and development. The objective of this study is to show the potential of RNA interference (RNAi) in the management of B. tabaci. RNAi is a sequence-specific gene silencing mechanism induced by double-stranded RNA (dsRNA) which holds tremendous potential in pest management. In this regard, we sequenced the GST from B. tabaci and synthesized approximately 500-bp dsRNA from the above and delivered through diet to B. tabaci. Real-time quantitative PCR (RT-qPCR) showed that continuous application of dsGST at 1.0, 0.5, and 0.25 μg/μl reduced mRNA expression levels for BtGST by 77.43, 64.86, and 52.95 % which resulted in mortality by 77, 59, and 40 %, respectively, after 72 h of application. Disruption of BtGST expression will enable the development of novel strategies in pest management and functional analysis of vital genes in B. tabaci.

  5. Toxicological and biochemical basis of synergism between the entomopathogenic fungus Lecanicillium muscarium and the insecticide matrine against Bemisia tabaci (Gennadius)

    NASA Astrophysics Data System (ADS)

    Ali, Shaukat; Zhang, Can; Wang, Zeqing; Wang, Xing-Min; Wu, Jian-Hui; Cuthbertson, Andrew G. S.; Shao, Zhenfang; Qiu, Bao-Li

    2017-04-01

    The sweetpotato whitefly Bemisia tabaci (Gennadius) was challenged with different combinations of matrine (insecticide) and Lecanicillium muscarium (entomopathogenic fungus). Our results revealed a synergistic relationship between matrine and L. muscarium on mortality and enzyme activities of B. tabaci. To illustrate the biochemical mechanisms involved in detoxification and immune responses of B. tabaci against both control agents, activities of different detoxifying and antioxidant enzymes were quantified. After combined application of matrine and L. muscarium, activities of carboxylestrease (CarE), glutathione-s-transferase (GSTs) and chitinase (CHI) decreased during the initial infection period. Acetylcholinestrase (AChE) activities increased during the entire experimental period, whereas those of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) decreased during the later infection period. The increased mortality and suppression of enzymatic response of B. tabaci following matrine and L. muscarium application suggests a strong synergistic effect between both agents. The strong synergistic effect is possibly related to the disturbance of acetylcholine balance and changes in AchE activities of the whitefly as both matrine and L. muscarium target insect acetylcholine (Ach) receptors which in turn effects AchE production. Therefore, our results have revealed the complex biochemical processes involved in the synergistic action of matrine and L. muscarium against B. tabaci.

  6. [Effects of alcohol extracts from three kinds of biomass energy plant tissues on biological activity of Bemisia tabaci].

    PubMed

    Zhou, Fu-cai; Zhou, Gui-sheng; Li, Chuan-ming; Yang, Yi-zhong; Qin, Pei

    2009-03-01

    To test the feasibility of using raw extracts from the tissues of biomass energy plants Ricinus communi and Kosteletzkya virginica as plant protection agents, the alcohol extracts from R. communi seed and leaf and from K. virginica leaf were used to treat adult Bemisia tabaci by spraying. The glutathione S-transferase and carboxylesterase activities in B. tabaci body were measured after treated for 4 h, 24 h, 48 h, 72 h, and 96 h, and the olfaction responses of B. tabaci to the alcohol extracts were detected with a Y-tube olfactomet. All the three alcohol extracts obviously inhibited the glutathione S-transferase and carboxylesterase activities in a concentration-dependent manner. The inhibitory effect of the 250-times diluted alcohol extracts on the two enzyme activities was equivalent to that of 3000 times-diluted 1.8% avermectins. In addition, the 250-times diluted alcohol extracts had obvious repellent effect on B. tabaci, with the repellent coefficient of the alcohol extracts from R. communi seed and leaf and from K, virginica leaf being 100.0%, 96.7%, and 79.4%, respectively. All of these suggested that the test three alcohol extracts had repellent and other biological effects on B. tabaci.

  7. Gene expression profiling in the thiamethoxam resistant and susceptible B-biotype sweetpotato whitefly, Bemisia tabaci.

    PubMed

    Xie, Wen; Yang, Xin; Wang, Shao-Ii; Wu, Qing-jun; Yang, Ni-na; Li, Ru-mei; Jiao, Xiao-guo; Pan, Hui-peng; Liu, Bai-ming; Feng, Yun-tao; Xu, Bao-yun; Zhou, Xu-guo; Zhang, You-jun

    2012-01-01

    Thiamethoxam has been used as a major insecticide to control the B-biotype sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). Due to its excessive use, a high level of resistance to thiamethoxam has developed worldwide over the past several years. To better understand the molecular mechanisms underlying this resistance in B. tabaci, gene profiles between the thiamethoxam-resistant and thiamethoxam-susceptible strains were investigated using the suppression subtractive hybridization (SSH) library approach. A total of 72 and 52 upand down-regulated genes were obtained from the forward and reverse SSH libraries, respectively. These expressed sequence tags (ESTs) belong to several functional categories based on their gene ontology annotation. Some categories such as cell communication, response to abiotic stimulus, lipid particle, and nuclear envelope were identified only in the forward library of thiamethoxam-resistant strains. In contrast, categories such as behavior, cell proliferation, nutrient reservoir activity, sequence-specific DNA binding transcription factor activity, and signal transducer activity were identified solely in the reverse library. To study the validity of the SSH method, 16 differentially expressed genes from both forward and reverse SSH libraries were selected randomly for further analyses using quantitative realtime PCR (qRT-PCR). The qRT-PCR results were fairly consistent with the SSH results; however, only 50% of the genes showed significantly different expression profiles between the thiamethoxam-resistant and thiamethoxam-susceptible whiteflies. Among these genes, a putative NAD-dependent methanol dehydrogenase was substantially over-expressed in the thiamethoxamresistant adults compared to their susceptible counterparts. The distributed profiles show that it was highly expressed during the egg stage, and was most abundant in the abdomen of adult females.

  8. Further insight into reproductive incompatibility between putative cryptic species of the Bemisia tabaci whitefly complex.

    PubMed

    Qin, Li; Pan, Li-Long; Liu, Shu-Sheng

    2016-04-01

    The whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), with its global distribution and extensive genetic diversity, is now known to be a complex of over 35 cryptic species. However, a satisfactory resolution of the systematics of this species complex is yet to be achieved. Here, we designed experiments to examine reproductive compatibility among species with different levels of mitochondrial cytochrome oxidase I (mtCOI) divergence. The data show that putative species with mtCOI divergence of >8% between them consistently exhibited complete reproductive isolation. However, two of the putative species, Asia II 9 and Asia II 3, with mtCOI divergence of 4.47% between them, exhibited near complete reproductive compatibility in one direction of their cross, and partial reproductive compatibility in the other direction. Together with some recent reports on this topic from the literature, our data indicates that, while divergence in the mtCOI sequences provides a valid molecular marker for species delimitation in most clades, more genetic markers and more sophisticated molecular phylogeny will be required to achieve adequate delimitation of all species in this whitefly complex. While many attempts have been made to examine the reproductive compatibility among genetic groups of the B. tabaci complex, our study represents the first effort to conduct crossing experiments with putative species that were chosen with considerations of their genetic divergence. In light of the new data, we discuss the best strategy and protocols to conduct further molecular phylogenetic analysis and crossing trials, in order to reveal the overall pattern of reproductive incompatibility among species of this whitefly complex. © 2015 Institute of Zoology, Chinese Academy of Sciences.

  9. Molecular characterization of soluble and membrane-bound trehalases of the whitefly, Bemisia tabaci.

    PubMed

    Wang, Jia; He, Wen-Bo; Su, Yun-Lin; Bing, Xiao-Li; Liu, Shu-Sheng

    2014-04-01

    Trehalases (Tres) have been demonstrated to be the key enzymes that are involved in various trehalose-associated physiological processes in insects. However, little attention has been devoted to the Tres in the whitefly, Bemisia tabaci. In this study, a soluble Tre (BtTre-1) and a membrane-bound Tre (BtTre-2) were cloned in the invasive cryptic species Middle East-Asia Minor 1 (MEAM1) of the whitefly B. tabaci complex. Alignment of deduced amino acids sequences of both BtTres revealed that they share common consensus regions and residues with Tres of other insect species. Levels of BtTres expression in various stages and tissues of the whitefly suggested that BtTre-2 may play a key role in trehalose catabolism during development of the whitefly, especially for oocyte development, while BtTre-1 may prevent trehalose in salivary gland from leaking and entering into plants along with saliva. Potential roles of trehalose catabolism in response to direct and/or plant-mediated indirect effects of Tomato Yellow Leaf Curl China Virus (TYLCCNV) were also detected. Whiteflies feeding on virus-infected tobacco plants showed higher BtTres expressions and accordingly higher BtTres activity but lower trehalose content than those feeding on uninfected plants. The enhanced trehalose catabolism may be beneficial to oocyte development in ovary and attenuate plant defensive responses induced by trehalose in saliva. Viruliferous and nonviruliferous whiteflies feeding on cotton, a nonhost plant for TYLCCNV, differed significantly only in trehalose content. The higher trehalose content in viruliferous whiteflies may be conducive to resisting the stress inflicted by TYLCCNV. © 2014 Wiley Periodicals, Inc.

  10. Assessment of cross-resistance potential to neonicotinoid insecticides in Bemisia tabaci (Hemiptera: Aleyrodidae).

    PubMed

    Prabhaker, N; Castle, S; Henneberry, T J; Toscano, N C

    2005-12-01

    Laboratory bioassays were carried out with four neonicotinoid insecticides on multiple strains of Bemisia tabaci (Gennadius) to evaluate resistance and cross-resistance patterns. Three imidacloprid-resistant strains and field populations from three different locations in the southwestern USA were compared in systemic uptake bioassays with acetamiprid, dinotefuran, imidacloprid and thiamethoxam. An imidacloprid-resistant strain (IM-R) with 120-fold resistance originally collected from Imperial Valley, California, did not show cross-resistance to acetamiprid, dinotefuran or thiamethoxam. The Guatemala-resistant strain (GU-R) that was also highly resistant to imidacloprid (RR=109-fold) showed low levels of cross-resistance when bioassayed with acetamiprid and thiamethoxam. However, dinotefuran was more toxic than either imidacloprid or thiamethoxam to both IM-R and GU-R strains as indicated by low LC50s. By contrast, a Q-biotype Spanish-resistant strain (SQ-R) of B. tabaci highly resistant to imidacloprid demonstrated high cross-resistance to the two related neonicotinoids. Field populations from Imperial Valley (California), Maricopa and Yuma (Arizona), showed variable susceptibility to imidacloprid (LC50s ranging from 3.39 to 115 microg ml(-1)) but did not exhibit cross-resistance to the three neonicotinoids suggesting that all three compounds would be effective in managing whiteflies. Yuma populations were the most susceptible to imidacloprid. Dinotefuran was the most toxic of the four neonicotinoids against field populations. Although differences in binding at the target site and metabolic pathways may influence the variability in cross-resistance patterns among whitefly populations, comparison of whitefly responses from various geographic regions to the four neonicotinoids indicates the importance of ecological and operational factors on development of cross-resistance to the neonicotinoids.

  11. Gene Expression Profiling in the Thiamethoxam Resistant and Susceptible B-biotype Sweetpotato Whitefly, Bemisia tabaci

    PubMed Central

    Xie, Wen; Yang, Xin; Wang, Shao-Ii; Wu, Qing-jun; Yang, Ni-na; Li, Ru-mei; Jiao, Xiaoguo; Pan, Hui-peng; Liu, Bai-ming; Feng, Yun-tao; Xu, Bao-yun; Zhou, Xu-guo; Zhang, You-jun

    2012-01-01

    Thiamethoxam has been used as a major insecticide to control the B-biotype sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). Due to its excessive use, a high level of resistance to thiamethoxam has developed worldwide over the past several years. To better understand the molecular mechanisms underlying this resistance in B. tabaci, gene profiles between the thiamethoxam-resistant and thiamethoxam-susceptible strains were investigated using the suppression subtractive hybridization (SSH) library approach. A total of 72 and 52 upand down-regulated genes were obtained from the forward and reverse SSH libraries, respectively. These expressed sequence tags (ESTs) belong to several functional categories based on their gene ontology annotation. Some categories such as cell communication, response to abiotic stimulus, lipid particle, and nuclear envelope were identified only in the forward library of thiamethoxam-resistant strains. In contrast, categories such as behavior, cell proliferation, nutrient reservoir activity, sequence-specific DNA binding transcription factor activity, and signal transducer activity were identified solely in the reverse library. To study the validity of the SSH method, 16 differentially expressed genes from both forward and reverse SSH libraries were selected randomly for further analyses using quantitative realtime PCR (qRT-PCR). The qRT-PCR results were fairly consistent with the SSH results; however, only 50% of the genes showed significantly different expression profiles between the thiamethoxam-resistant and thiamethoxam-susceptible whiteflies. Among these genes, a putative NAD-dependent methanol dehydrogenase was substantially over-expressed in the thiamethoxamresistant adults compared to their susceptible counterparts. The distributed profiles show that it was highly expressed during the egg stage, and was most abundant in the abdomen of adult females. PMID:22957505

  12. DNA barcoding of Bemisia tabaci complex (Hemiptera: Aleyrodidae) reveals southerly expansion of the dominant whitefly species on cotton in Pakistan.

    PubMed

    Ashfaq, Muhammad; Hebert, Paul D N; Mirza, M Sajjad; Khan, Arif M; Mansoor, Shahid; Shah, Ghulam S; Zafar, Yusuf

    2014-01-01

    Although whiteflies (Bemisia tabaci complex) are an important pest of cotton in Pakistan, its taxonomic diversity is poorly understood. As DNA barcoding is an effective tool for resolving species complexes and analyzing species distributions, we used this approach to analyze genetic diversity in the B. tabaci complex and map the distribution of B. tabaci lineages in cotton growing areas of Pakistan. Sequence diversity in the DNA barcode region (mtCOI-5') was examined in 593 whiteflies from Pakistan to determine the number of whitefly species and their distributions in the cotton-growing areas of Punjab and Sindh provinces. These new records were integrated with another 173 barcode sequences for B. tabaci, most from India, to better understand regional whitefly diversity. The Barcode Index Number (BIN) System assigned the 766 sequences to 15 BINs, including nine from Pakistan. Representative specimens of each Pakistan BIN were analyzed for mtCOI-3' to allow their assignment to one of the putative species in the B. tabaci complex recognized on the basis of sequence variation in this gene region. This analysis revealed the presence of Asia II 1, Middle East-Asia Minor 1, Asia 1, Asia II 5, Asia II 7, and a new lineage "Pakistan". The first two taxa were found in both Punjab and Sindh, but Asia 1 was only detected in Sindh, while Asia II 5, Asia II 7 and "Pakistan" were only present in Punjab. The haplotype networks showed that most haplotypes of Asia II 1, a species implicated in transmission of the cotton leaf curl virus, occurred in both India and Pakistan. DNA barcodes successfully discriminated cryptic species in B. tabaci complex. The dominant haplotypes in the B. tabaci complex were shared by India and Pakistan. Asia II 1 was previously restricted to Punjab, but is now the dominant lineage in southern Sindh; its southward spread may have serious implications for cotton plantations in this region.

  13. Biotype expression and insecticide response of Bemisia tabaci chemosensory protein-1.

    PubMed

    Liu, Guo Xia; Xuan, Ning; Chu, Dong; Xie, Hong Yan; Fan, Zhong Xue; Bi, Yu Ping; Picimbon, Jean-François; Qin, Yu Chuan; Zhong, Su Ting; Li, Yao Fa; Gao, Zhan Lin; Pan, Wen Liang; Wang, Guo Ying; Rajashekar, Balaji

    2014-03-01

    Chemosensory proteins (CSPs) are a group of small soluble proteins found so far exclusively in arthropod species. These proteins act in chemical communication and perception. In this study, a gene encoding the Type 1 CSP (BtabCSP1) from the agricultural pest Bemisia tabaci (whitefly) was analyzed to understand sequence variation and expression specificity in different biotypes. Sequence analysis of BtabCSP1 showed significant differences between the two genetically characterized biotypes, B and Q. The B-biotype had a larger number of BtabCSP1 mutations than the Q-biotype. Similar to most other CSPs, BtabCSP1 was more expressed in the head than in the rest of the body. One-step RT-PCR and qPCR analysis on total messenger RNA showed that biotype-Q had higher BtabCSP1 expression levels than biotype-B. Females from a mixed field-population had high levels of BtabCSP1 expression. The interaction of BtabCSP1 with the insecticide thiamethoxam was investigated by analyzing the BtabCSP1 expression levels following exposure to the neonicotinoid, thiamethoxam, in a time/dose-response study. Insecticide exposure increased BtabCSP1 expression (up to tenfold) at 4 and 24 h following 50 or 100 g/ml treatments. © 2014 Wiley Periodicals, Inc.

  14. Dynamics of resistance to the neonicotinoids acetamiprid and thiamethoxam in Bemisia tabaci (Homoptera: Aleyrodidae).

    PubMed

    Horowitz, A Rami; Kontsedalov, Svetlana; Ishaaya, Isaac

    2004-12-01

    The dynamics of resistance in the sweetpotato whitefly, Bemisia tabaci (Gennadius), to the neonicotinoids acetamiprid and thiamethoxam was studied extensively in cotton fields in Israel during the cotton-growing seasons 1999-2003. Whitefly strains were collected in early and late seasons mainly in three locations in northern, central, and southern Israel. The whiteflies were assayed under laboratory conditions for susceptibility to neonicotinoids, as part of the Israeli cotton insecticide resistance management strategy. Selections to both acetamiprid and thiamethoxam and cross-resistance between them also were conducted in the laboratory. Although no appreciable resistance to acetamiprid was observed up to 2001, a slight increase of approximately five-fold resistance was detected during 2002 and 2003. However, from 2001 to 2003 thiamethoxam resistance increased >100-fold in the Ayalon Valley and Carmel Coast cotton fields. In cross-resistance assays with both neonicotinoids, the strain that had been selected with thiamethoxam for 12 generations demonstrated almost no cross-resistance to acetamiprid, whereas the acetamiprid-selected strain exhibited high cross-resistance of >500-fold to thiamethoxam.

  15. Effect of Zohar LQ-215, a biorational surfactant, on the sweetpotato whitefly Bemisia tabaci (biotype b).

    PubMed

    Ishaaya, I; Khasdan, V; Horowitz, A Rami

    2006-01-01

    Zohar LQ-215, a surfactant based on plant oils, able to control nymphs of the whitefly, Bemisia tabaci (Gennadius), under laboratory and field conditions. To evaluate the effects of the surfactant on the nymph stages of whitefly under laboratory conditions, potted cotton seedlings infested with 1st- or 3rd-instars were treated with the compound aqueous solutions. LC90 values of Zohar LQ-215 on 1st and 3rd-nymphs, based on mortality curves, were 0.78% and 1.14%, respectively. Adult mortality of 12% and 19% was obtained at concentrations of 0.5% and 1%, respectively. Under both laboratory and, in some cases, under field conditions, greater mortality was achieved when combining Zohar LQ-215 with the insect growth regulator buprofezin than when either insecticide was applied separately. Our results indicate that Zohar LQ-215 could serve as a potential compound for controlling whiteflies under light to moderate infestation and could be used in combination with other rational insecticides such as buprofezin for controlling whiteflies in integrated pest management programs.

  16. Expression Profiling in Bemisia tabaci under Insecticide Treatment: Indicating the Necessity for Custom Reference Gene Selection

    PubMed Central

    Zhou, Xuguo; Gao, Xiwu

    2014-01-01

    Finding a suitable reference gene is the key for qRT-PCR analysis. However, none of the reference gene discovered thus far can be utilized universally under various biotic and abiotic experimental conditions. In this study, we further examine the stability of candidate reference genes under a single abiotic factor, insecticide treatment. After being exposed to eight commercially available insecticides, which belong to five different classes, the expression profiles of eight housekeeping genes in the sweetpotato whitefly, Bemisia tabaci, one of the most invasive and destructive pests in the world, were investigated using qRT-PCR analysis. In summary, elongation factor 1α (EF1α), α-tubulin (TUB1α) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were identified as the most stable reference genes under the insecticide treatment. The initial assessment of candidate reference genes was further validated with the expression of two target genes, a P450 (Cyp6cm1) and a glutathione S-transferase (GST). However, ranking of reference genes varied substantially among intra- and inter-classes of insecticides. These combined data strongly suggested the necessity of conducting custom reference gene selection designed for each and every experimental condition, even when examining the same abiotic or biotic factor. PMID:24498122

  17. Bioactivity of indigenous medicinal plants against the cotton whitefly, Bemisia tabaci.

    PubMed

    Hammad, E Abou-Fakhr; Zeaiter, A; Saliba, N; Talhouk, S

    2014-01-01

    Forty-one methanol extracts of 28 indigenous medicinal plant species were tested for their insecticidal bioactivity against cotton whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), adults and second nymphal instars under controlled conditions. This study is within a bioprospection context, in the form of utilizing local plant species as an alternative in sustainable agriculture development. Eighteen and nine plant extracts caused a significant decrease in number of live adult and nymphal whiteflies, respectively, compared to the control. This is the first report for the potential effect on survival of insects for 22 out of 28 tested medicinal plant species. Whole plant extracts of Ranunculus myosuroudes Boiss. and Kotschy (Ranunculaceae), Achillea damascena L. (Asteraceae), and Anthemis hebronica Boiss. and Kotschy (Asteraceae) and leaf extracts of Verbascum leptostychum DC. (Scrophulariaceae) and Heliotropium rotundifolium Boiss. (Borangiaceae) caused both repellent and toxic effects against the adult and second nymphal instars, respectively. Extracts of leaves and stems of Anthemis scariosa Boiss. (Asteraceae) and Calendula palestina Pers. (Asteraceae) were found to be more bioactive against the adult and nymphal instars, respectively, than extracts of other plant parts, such as flowers. Thus, the bioactive extracts of these medicinal plants have the potential to lower whitefly populations in a comprehensive pest management program in local communities, pending cultivation of these medicinal plant species.

  18. Cloning, Expression and Characterization of Mitochondrial Manganese Superoxide Dismutase from the Whitefly, Bemisia tabaci

    PubMed Central

    Gao, Xian-Long; Li, Jun-Min; Wang, Yong-Liang; Jiu, Min; Yan, Gen-Hong; Liu, Shu-Sheng; Wang, Xiao-Wei

    2013-01-01

    A mitochondrial manganese superoxide dismutase from an invasive species of the whitefly Bemisia tabaci complex (Bt-mMnSOD) was cloned and analyzed. The full length cDNA of Bt-mMnSOD is 1210 bp with a 675 bp open reading frame, corresponding to 224 amino acids, which include 25 residues of the mitochondrial targeting sequence. Compared with various vertebrate and invertebrate animals, the MnSOD signature (DVWEHAYY) and four conserved amino acids for manganese binding (H54, H102, D186 and H190) were observed in Bt-mMnSOD. Recombinant Bt-mMnSOD was overexpressed in Escherichia coli, and the enzymatic activity of purified mMnSOD was assayed under various temperatures. Quantitative real-time PCR analysis with whiteflies of different development stages showed that the mRNA levels of Bt-mMnSOD were significantly higher in the 4th instar than in other stages. In addition, the in vivo activities of MnSOD in the whitefly were measured under various conditions, including exposure to low (4 °C) and high (40 °C) temperatures, transfer from a favorable to an unfavorable host plant (from cotton to tobacco) and treatment with pesticides. Our results indicate that the whitefly MnSOD plays an important role in cellular stress responses and anti-oxidative processes and that it might contribute to the successful worldwide distribution of the invasive whitefly. PMID:23296268

  19. Cloning, expression and characterization of mitochondrial manganese superoxide dismutase from the Whitefly, Bemisia tabaci.

    PubMed

    Gao, Xian-Long; Li, Jun-Min; Wang, Yong-Liang; Jiu, Min; Yan, Gen-Hong; Liu, Shu-Sheng; Wang, Xiao-Wei

    2013-01-07

    A mitochondrial manganese superoxide dismutase from an invasive species of the whitefly Bemisia tabaci complex (Bt-mMnSOD) was cloned and analyzed. The full length cDNA of Bt-mMnSOD is 1210 bp with a 675 bp open reading frame, corresponding to 224 amino acids, which include 25 residues of the mitochondrial targeting sequence. Compared with various vertebrate and invertebrate animals, the MnSOD signature (DVWEHAYY) and four conserved amino acids for manganese binding (H54, H102, D186 and H190) were observed in Bt-mMnSOD. Recombinant Bt-mMnSOD was overexpressed in Escherichia coli, and the enzymatic activity of purified mMnSOD was assayed under various temperatures. Quantitative real-time PCR analysis with whiteflies of different development stages showed that the mRNA levels of Bt-mMnSOD were significantly higher in the 4th instar than in other stages. In addition, the in vivo activities of MnSOD in the whitefly were measured under various conditions, including exposure to low (4 °C) and high (40 °C) temperatures, transfer from a favorable to an unfavorable host plant (from cotton to tobacco) and treatment with pesticides. Our results indicate that the whitefly MnSOD plays an important role in cellular stress responses and anti-oxidative processes and that it might contribute to the successful worldwide distribution of the invasive whitefly.

  20. Whitefly Bemisia tabaci (Homoptera: Aleyrodidae) infestation on cassava genotypes grown at different ecozones in Nigeria.

    PubMed

    Ariyo, O A; Dixon, A G O; Atiri, G I

    2005-04-01

    Large-scale screening of cassava, Manihot esculenta Crantz, genotypes for resistance to infestation by whitefly Bemisia tabaci Gennadius, the vector of cassava mosaic geminiviruses, is limited. A range of new cassava elite clones were therefore assessed for the whitefly infestation in the 1999/2000 and 2000/2001 cropping seasons in experimental fields of International Institute of Tropical Agriculture, Ibadan, Nigeria. On each scoring day, between 0600 and 0800 hours when the whiteflies were relatively immobile, adult whitefly populations on the five topmost expanded leaves of cassava cultivars were counted. All through the 6-mo scoring period, there was a highly significant difference in whitefly infestation among the new cassava elite clones. Vector population buildup was observed in Ibadan (forest-savanna transition zone) and Onne (humid forest), 2 mo after planting (MAP). Mean infestation across cassava genotypes was significantly highest (16.6 whiteflies per plant) in Ibadan and lowest in Zaria (0.2). Generally, whitefly infestation was very low in all locations at 5 and 6 MAP. During this period, cassava genotypes 96/1439 and 91/02324 significantly supported higher infestations than other genotypes. Plants of 96/1089A and TMS 30572 supported the lowest whitefly infestation across cassava genotypes in all locations. The preferential whitefly visitation, the differences between locations in relation to whitefly population, cassava mosaic disease, and the fresh root yield of cassava genotypes are discussed.

  1. Bioactivity of Indigenous Medicinal Plants against the Cotton Whitefly, Bemisia tabaci

    PubMed Central

    Hammad, E. Abou-Fakhr; Zeaiter, A.; Saliba, N.; Talhouk, S.

    2014-01-01

    Forty-one methanol extracts of 28 indigenous medicinal plant species were tested for their insecticidal bioactivity against cotton whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), adults and second nymphal instars under controlled conditions. This study is within a bioprospection context, in the form of utilizing local plant species as an alternative in sustainable agriculture development. Eighteen and nine plant extracts caused a significant decrease in number of live adult and nymphal whiteflies, respectively, compared to the control. This is the first report for the potential effect on survival of insects for 22 out of 28 tested medicinal plant species. Whole plant extracts of Ranunculus myosuroudes Boiss. and Kotschy (Ranunculaceae), Achillea damascena L. (Asteraceae), and Anthemis hebronica Boiss. and Kotschy (Asteraceae) and leaf extracts of Verbascum leptostychum DC. (Scrophulariaceae) and Heliotropium rotundifolium Boiss. (Borangiaceae) caused both repellent and toxic effects against the adult and second nymphal instars, respectively. Extracts of leaves and stems of Anthemis scariosa Boiss. (Asteraceae) and Calendula palestina Pers. (Asteraceae) were found to be more bioactive against the adult and nymphal instars, respectively, than extracts of other plant parts, such as flowers. Thus, the bioactive extracts of these medicinal plants have the potential to lower whitefly populations in a comprehensive pest management program in local communities, pending cultivation of these medicinal plant species. PMID:25204756

  2. Female-Biased Symbionts and Tomato Yellow Leaf Curl Virus Infections in Bemisia tabaci

    PubMed Central

    Guo, Huifang; Qu, Yufeng; Liu, Xiangdong; Zhong, Wanfang; Fang, Jichao

    2014-01-01

    The female-biased infection of facultative symbionts has been found in Bemisia tabaci; however, whether there are any differences in tomato yellow leaf curl virus (TYLCV) and obligate symbiont infection rates between females and males is unknown. Determining whether such differences exist would be very important for understanding the spread of the plant virus and of the symbionts. We compared both symbiont infection types, including obligate and facultative symbionts, and the rates of TYLCV infection in both sexes in five field populations from Jiangsu Province, China. The obligate symbiont Portiera aleyrodidarum was not found in every whitefly tested. In all tested populations, more females than males were found to harbor P. aleyrodidarum; and more females than males also harbored Hamiltonella defense, the most common facultative symbiont as well as Cardinium. In addition to female-biased symbiont infections, there were also female-biased TYLCV infections, and the infection frequencies of this plant virus in females were higher than those in males. Taken together, these results suggested that both the female-biased symbiont infections and female-biased TYLCV infections promoted the rapid spread of TYLCV in China. PMID:24465416

  3. RNAi-mediated resistance to whitefly (Bemisia tabaci) in genetically engineered lettuce (Lactuca sativa).

    PubMed

    Ibrahim, Abdulrazak B; Monteiro, Tatiane R; Cabral, Glaucia B; Aragão, Francisco J L

    2017-07-15

    RNA interference (RNAi)-based transgenic technologies have evolved as potent biochemical tools for silencing specific genes of plant pathogens and pests. The approach has been demonstrated to be useful in silencing genes in insect species. Here, we report on the successful construction of RNAi-based plasmid containing an interfering cassette designed to generate dsRNAs that target a novel v-ATPase transcript in whitefly (Bemisia tabaci), an important agricultural pest in tropical and sub-tropical regions. The presence of the transgene was confirmed in T0 and T1 generations of transgenic lettuce lines, segregating in a Mendelian fashion. Seven lines were infested with whiteflies and monitored over a period of 32 days. Analysis of mortality showed that within five days of feeding, insects on transgenic plants showed a mortality rate of 83.8-98.1%. In addition, a reduced number of eggs (95 fold less) was observed in flies feeding on transgenic lettuce plants than insects on control lines. Quantitative reverse transcription PCR showed decreased expression level of endogenous v-ATPase gene in whiteflies feeding on transgenic plants. This technology is a foundation for the production of whitefly-resistant commercial crops, improving agricultural sustainability and food security, reducing the use of more environmentally aggressive methods of pest control.

  4. Bioactivity of indigenous medicinal plants against the cotton whitefly, Bemisia tabaci.

    PubMed

    Hammad, E Abou-Fakhr; Zeaiter, A; Saliba, N; Talhouk, S

    2014-01-01

    Forty-one methanol extracts of 28 indigenous medicinal plant species were tested for their insecticidal bioactivity against cotton whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), adults and second nymphal instars under controlled conditions. This study is within a bioprospection context, in the form of utilizing local plant species as an alternative in sustainable agriculture development. Eighteen and nine plant extracts caused a significant decrease in number of live adult and nymphal whiteflies, respectively, compared to the control. This is the first report for the potential effect on survival of insects for 22 out of 28 tested medicinal plant species. Whole plant extracts of Ranunculus myosuroudes Boiss. and Kotschy (Ranunculaceae),Achillea damascena L. (Asteraceae), and Anthemis hebronica Boiss. and Kotschy (Asteraceae) and leaf extracts of Verbascum leptostychum DC. (Scrophulariaceae) and Heliotropium rotundifolium Boiss. (Borangiaceae) caused both repellent and toxic effects against the adult and second nymphal instars, respectively. Extracts of leaves and stems of Anthemis scariosa Boiss. (Asteraceae) and Calendula palestina Pers. (Asteraceae) were found to be more bioactive against the adult and nymphal instars, respectively, than extracts of other plant parts, such as flowers. Thus, the bioactive extracts of these medicinal plants have the potential to lower whitefly populations in a comprehensive pest management program in local communities, pending cultivation of these medicinal plant species. This is an open access paper. We use the Creative Commons Attribution 3.0 license that permits unrestricted use, provided that the paper is properly attributed.

  5. Role of the Insect Supervectors Bemisia tabaci and Frankliniella occidentalis in the Emergence and Global Spread of Plant Viruses.

    PubMed

    Gilbertson, Robert L; Batuman, Ozgur; Webster, Craig G; Adkins, Scott

    2015-11-01

    Emergence of insect-transmitted plant viruses over the past 10-20 years has been disproportionately driven by two so-called supervectors: the whitefly, Bemisia tabaci, and the Western flower thrips, Frankliniella occidentalis. High rates of reproduction and dispersal, extreme polyphagy, and development of insecticide resistance, together with human activities, have made these insects global pests. These supervectors transmit a diversity of plant viruses by different mechanisms and mediate virus emergence through local evolution, host shifts, mixed infections, and global spread. Associated virus evolution involves reassortment, recombination, and component capture. Emergence of B. tabaci-transmitted geminiviruses (begomoviruses), ipomoviruses, and torradoviruses has led to global disease outbreaks as well as multiple paradigm shifts. Similarly, F. occidentalis has mediated tospovirus host shifts and global dissemination and the emergence of pollen-transmitted ilarviruses. The plant virus-supervector interaction offers exciting opportunities for basic research and global implementation of generalized disease management strategies to reduce economic and environmental impacts.

  6. The Dynamics and Environmental Influence on Interactions Between Cassava Brown Streak Disease and the Whitefly, Bemisia tabaci.

    PubMed

    Jeremiah, S C; Ndyetabula, I L; Mkamilo, G S; Haji, S; Muhanna, M M; Chuwa, C; Kasele, S; Bouwmeester, H; Ijumba, J N; Legg, J P

    2015-05-01

    Cassava brown streak disease (CBSD) is currently the most significant virus disease phenomenon affecting African agriculture. In this study, we report results from the most extensive set of field data so far presented for CBSD in Africa. From assessments of 515 farmers' plantings of cassava, incidence in the Coastal Zone of Tanzania (46.5% of plants; 87% of fields affected) was higher than in the Lake Zone (22%; 34%), but incidences for both zones were greater than previous published records. The whitefly vector, Bemisia tabaci, was more abundant in the Lake Zone than the Coastal Zone, the reverse of the situation reported previously, and increased B. tabaci abundance is driving CBSD spread in the Lake Zone. The altitudinal "ceiling" previously thought to restrict the occurrence of CBSD to regions <1,000 masl has been broken as a consequence of the greatly increased abundance of B. tabaci in mid-altitude areas. Among environmental variables analyzed, minimum temperature was the strongest determinant of CBSD incidence. B. tabaci in the Coastal and Lake Zones responded differently to environmental variables examined, highlighting the biological differences between B. tabaci genotypes occurring in these regions and the superior adaptation of B. tabaci in the Great Lakes region both to cassava and low temperature conditions. Regression analyses using multi-country data sets could be used to determine the potential environmental limits of CBSD. Approaches such as this offer potential for use in the development of predictive models for CBSD, which could strengthen country- and continent-level CBSD pandemic mitigation strategies.

  7. Isolation and identification of culturable bacteria from honeydew of whitefly, Bemisia tabaci (G.) (Hemiptera: Aleyrodidae)☆

    PubMed Central

    H.K., Roopa; K.B., Rebijith; R., Asokan; Mahmood, Riaz; N.K., Krishna Kumar

    2014-01-01

    Bemisia tabaci (G.) is an important pest and a vector of Gemini viruses infecting plants. During the process of feeding B. tabaci excretes honeydew which is rich in nutrients, and an excellent medium for microbial growth. Recent report proved that volatile emitted by the honeydew associated bacteria of aphid, Acyrthosiphon pisum Harris was involved in natural enemy calling. Thus understanding the honeydew associated bacteria is of paramount importance from the non-chemical method of insect pest management. In this perspective, very less information is available on bacteria associated with the honeydew excreted by B. tabaci. Therefore, in the present study we have isolated and characterized three culturable bacteria from the honeydew of B. tabaci viz. Bacillus endophyticus, Bacillus niacini and Roseomonas species by employing 16Sr DNA BLASTx analyses which revealed that both B. endophyticus and B. niacini had high similarity (> 99%) to the respective species, while Roseomonas sp. showed only 95% similarity to the existing Roseomonas sp. specificity of honeydew association of Roseomonas sp. was confirmed by developing specific primers as this genus is reported from immunocompromised persons and recently from ticks and mites. The present study also indicated the possible host-plant origin of these honeydew associated bacteria. PMID:25606395

  8. Elevated O3 and TYLCV Infection Reduce the Suitability of Tomato as a Host for the Whitefly Bemisia tabaci

    PubMed Central

    Cui, Hongying; Sun, Yucheng; Chen, Fajun; Zhang, Youjun; Ge, Feng

    2016-01-01

    The effects of elevated atmospheric ozone (O3) levels on herbivorous insects have been well studied, but little is known about the combined effects of elevated O3 and virus infection on herbivorous insect performance. Using open-top chambers in the field, we determined the effects of elevated O3 and Tomato yellow leaf curl virus (TYLCV) infection on wild-type (Wt) tomato and 35S tomato (jasmonic acid (JA) defense-enhanced genotype) in association with whitefly, Bemisia tabaci Gennadius biotype B. Elevated O3 and TYLCV infection, alone and in combination, significantly reduced the contents of soluble sugars and free amino acids, increased the contents of total phenolics and condensed tannins, and increased salicylic acid (SA) content and the expression of SA-related genes in leaves. The JA signaling pathway was upregulated by elevated O3, but downregulated by TYLCV infection and O3 + TYLCV infection. Regardless of plant genotype, elevated O3, TYLCV infection, or O3 + TYLCV infection significantly decreased B. tabaci fecundity and abundance. These results suggest that elevated O3 and TYLCV infection, alone and in combination, reduce the nutrients available for B. tabaci, increase SA content and SA-related gene expression, and increase secondary metabolites, resulting in decreases in fecundity and abundance of B. tabaci in both tomato genotypes. PMID:27916792

  9. Single basal application of thiacloprid for the integrated management of Meloidogyne incognita and Bemisia tabaci in tomato crops

    PubMed Central

    Dong, Sa; Ren, Xiaofen; Zhang, Dianli; Ji, Xiaoxue; Wang, Kaiyun; Qiao, Kang

    2017-01-01

    Tomato growers commonly face heavy nematode (Meloidogyne incognita) and whitefly (B-biotype Bemisia tabaci) infestations, and previous studies demonstrated that thiacloprid could be used to control M. incognita and B. tabaci in cucumber. However, the efficacy of a single basal application of thiacloprid to control both pests and its effect on yield in tomato remains unknown. In this study, the potential of thiacloprid application to the soil for the integrated control of M. incognita and B. tabaci in tomato was evaluated in the laboratory and the field. Laboratory tests showed that thiacloprid was highly toxic to whitefly adults and eggs with an average lethal concentration 50 (LC50) of 14.7 and 62.2 mg ai L−1, respectively, and the LC50 of thiacloprid for nematode J2s and eggs averaged 36.2 and 70.4 mg ai L−1, respectively. In field trials, when thiacloprid was applied to the soil at 7.5, 15 and 30 kg ha−1 in two consecutive years, whitefly adults decreased by 37.8–75.4% within 60 days of treatment, and the root-galling index was reduced by 31.8–85.2%. Optimum tomato plant growth and maximum yields were observed in the 15 kg ha−1 treatment. The results indicated that a single basal application of thiacloprid could control M. incognita and B. tabaci and enhance tomato growth and yield. PMID:28120937

  10. Three Members of the Bemisia tabaci (Hemiptera: Aleyrodidae) Cryptic Species Complex Occur Sympatrically in Argentine Horticultural Crops.

    PubMed

    Alemandri, V; Vaghi Medina, C G; Dumón, A D; Argüello Caro, E B; Mattio, M F; García Medina, S; López Lambertini, P M; Truol, G

    2015-04-01

    The whitefly, Bemisia tabaci (Gennadius), is a cryptic species complex that attacks >600 different species of plants and transmits several plant viruses causing severe economic losses. Until 2010, the B. tabaci complex comprised 24 distinct putative species. Recently, at least 15 new species have been reported. The objective of this study was to identify B. tabaci species present in bean, melon, and tomato crops in Argentina by applying phylogenetic analyses and pairwise comparison of genetic distances of mitochondrial cytochrome c oxidase subunit I (mtCOI) sequences. The 39 proposed whitefly species were identified with both analyses, and the presence in Argentina of one indigenous species, New World 2 (NW2), and two introduced species, Middle East-Asia Minor one (MEAM1) and Mediterranean, was confirmed. Common bean crop presented the three whitefly species detected, with NW2, MEAM1, and Mediterranean being present all together under field conditions. Also, Mediterranean was the only species identified in tomato, whereas MEAM1 was found in melon. To the best of our knowledge, Mediterranean is a recent invasive species in open-field agriculture in the American continent and in greenhouse tomato in Argentina. Additionally, we provide the first report of MEAM1 in common bean and melon. These findings raise several questions on the future scenario of B. tabaci and the viruses it transmits in Argentina. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Reference Gene Selection for qRT-PCR Analysis in the Sweetpotato Whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae)

    PubMed Central

    Li, Rumei; Xie, Wen; Wang, Shaoli; Wu, Qingjun; Yang, Nina; Yang, Xin; Pan, Huipeng; Zhou, Xiaomao; Bai, Lianyang; Xu, Baoyun; Zhou, Xuguo; Zhang, Youjun

    2013-01-01

    Background Accurate evaluation of gene expression requires normalization relative to the expression of reliable reference genes. Expression levels of “classical” reference genes can differ, however, across experimental conditions. Although quantitative real-time PCR (qRT-PCR) has been used extensively to decipher gene function in the sweetpotato whitefly Bemisia tabaci, a world-wide pest in many agricultural systems, the stability of its reference genes has rarely been validated. Results In this study, 15 candidate reference genes from B. tabaci were evaluated using two Excel-based algorithms geNorm and Normfinder under a diverse set of biotic and abiotic conditions. At least two reference genes were selected to normalize gene expressions in B. tabaci under experimental conditions. Specifically, for biotic conditions including host plant, acquisition of a plant virus, developmental stage, tissue (body region of the adult), and whitefly biotype, ribosomal protein L29 was the most stable reference gene. In contrast, the expression of elongation factor 1 alpha, peptidylprolyl isomerase A, NADH dehydrogenase, succinate dehydrogenase complex subunit A and heat shock protein 40 were consistently stable across various abiotic conditions including photoperiod, temperature, and insecticide susceptibility. Conclusion Our finding is the first step toward establishing a standardized quantitative real-time PCR procedure following the MIQE (Minimum Information for publication of Quantitative real time PCR Experiments) guideline in an agriculturally important insect pest, and provides a solid foundation for future RNA interference based functional study in B. tabaci. PMID:23308130

  12. Reference gene selection for qRT-PCR analysis in the sweetpotato whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae).

    PubMed

    Li, Rumei; Xie, Wen; Wang, Shaoli; Wu, Qingjun; Yang, Nina; Yang, Xin; Pan, Huipeng; Zhou, Xiaomao; Bai, Lianyang; Xu, Baoyun; Zhou, Xuguo; Zhang, Youjun

    2013-01-01

    Accurate evaluation of gene expression requires normalization relative to the expression of reliable reference genes. Expression levels of "classical" reference genes can differ, however, across experimental conditions. Although quantitative real-time PCR (qRT-PCR) has been used extensively to decipher gene function in the sweetpotato whitefly Bemisia tabaci, a world-wide pest in many agricultural systems, the stability of its reference genes has rarely been validated. In this study, 15 candidate reference genes from B. tabaci were evaluated using two Excel-based algorithms geNorm and Normfinder under a diverse set of biotic and abiotic conditions. At least two reference genes were selected to normalize gene expressions in B. tabaci under experimental conditions. Specifically, for biotic conditions including host plant, acquisition of a plant virus, developmental stage, tissue (body region of the adult), and whitefly biotype, ribosomal protein L29 was the most stable reference gene. In contrast, the expression of elongation factor 1 alpha, peptidylprolyl isomerase A, NADH dehydrogenase, succinate dehydrogenase complex subunit A and heat shock protein 40 were consistently stable across various abiotic conditions including photoperiod, temperature, and insecticide susceptibility. Our finding is the first step toward establishing a standardized quantitative real-time PCR procedure following the MIQE (Minimum Information for publication of Quantitative real time PCR Experiments) guideline in an agriculturally important insect pest, and provides a solid foundation for future RNA interference based functional study in B. tabaci.

  13. Identification, characterization and expression of a defensin-like antifungal peptide from the whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae).

    PubMed

    Wang, Z-Z; Shi, M; Ye, X-Q; Chen, M-Y; Chen, X-X

    2013-06-01

    Defensins are a class of small and diverse cysteine-rich proteins which have broad-spectrum antimicrobial activities. We identified and characterized a full-length cDNA encoding a putative defensin-like peptide from the whitefly Bemisia tabaci by RACE and quantitative real-time (qRT)-PCR. The full-length cDNA, named Btdef, was 388 bp long and contained an open reading frame of 228 bp. The putative mature Btdef had 46 amino acids with a molecular weight of 5.06 kDa. The deduced amino acid sequence showed significant homology with insect defensins from Heliothis virescens (76%) and Galleria mellonella (75%). The predicted mature form of Btdef was expressed as a recombinant peptide in Escherichia coli. Antimicrobial assays of the purified product indicated that Btdef was most active against fungi. qRT-PCR analyses indicated that Btdef mRNA was constitutively expressed in different tissues of B. tabaci, including fat body, midgut, ovaries and salivary gland, and was induced by fungal infection. Btdef mRNA expression was also significantly altered after feeding on different host plants, indicating that diet affects immune defences in B. tabaci. These results describe for the first time the basic properties of a defensin-like peptide from B. tabaci that probably plays an important role in the immune response against pathogens. © 2013 Royal Entomological Society.

  14. Inoculation of tomato plants with rhizobacteria enhances the performance of the phloem-feeding insect Bemisia tabaci.

    PubMed

    Shavit, Roee; Ofek-Lalzar, Maya; Burdman, Saul; Morin, Shai

    2013-01-01

    In their natural environment, plants experience multiple biotic interactions and respond to this complexity in an integrated manner. Therefore, plant responses to herbivory are flexible and depend on the context and complexity in which they occur. For example, plant growth promoting rhizobacteria (PGPR) can enhance plant growth and induce resistance against microbial pathogens and herbivorous insects by a phenomenon termed induced systemic resistance (ISR). In the present study, we investigated the effect of tomato (Solanum lycopersicum) pre-inoculation with the PGPR Pseudomonas fluorescens WCS417r, on the performance of the generalist phloem-feeding insect Bemisia tabaci. Based on the ability of P. fluorescens WCS417r to prime for ISR against generalists chewing insects and necrotrophic pathogens, we hypothesized that pre-inoculated plants will strongly resist B. tabaci infestation. In contrast, we discovered that the pre-inoculation treatment increased the tomato plant suitability for B. tabaci which was emphasized both by faster developmental rate and higher survivability of nymph stages on pre-inoculated plants. Our molecular and chemical analyses suggested that the phenomenon is likely to be related to: (I) the ability of the bacteria to reduce the activity of the plant induced defense systems; (II) a possible manipulation by P. fluorescens of the plant quality (in terms of suitability for B. tabaci) through an indirect effect on the rhizosphere bacterial community. The contribution of our study to the pattern proposed for other belowground rhizobacteria and mycorrhizal fungi and aboveground generalist phloem-feeders is discussed.

  15. Single basal application of thiacloprid for the integrated management of Meloidogyne incognita and Bemisia tabaci in tomato crops

    NASA Astrophysics Data System (ADS)

    Dong, Sa; Ren, Xiaofen; Zhang, Dianli; Ji, Xiaoxue; Wang, Kaiyun; Qiao, Kang

    2017-01-01

    Tomato growers commonly face heavy nematode (Meloidogyne incognita) and whitefly (B-biotype Bemisia tabaci) infestations, and previous studies demonstrated that thiacloprid could be used to control M. incognita and B. tabaci in cucumber. However, the efficacy of a single basal application of thiacloprid to control both pests and its effect on yield in tomato remains unknown. In this study, the potential of thiacloprid application to the soil for the integrated control of M. incognita and B. tabaci in tomato was evaluated in the laboratory and the field. Laboratory tests showed that thiacloprid was highly toxic to whitefly adults and eggs with an average lethal concentration 50 (LC50) of 14.7 and 62.2 mg ai L-1, respectively, and the LC50 of thiacloprid for nematode J2s and eggs averaged 36.2 and 70.4 mg ai L-1, respectively. In field trials, when thiacloprid was applied to the soil at 7.5, 15 and 30 kg ha-1 in two consecutive years, whitefly adults decreased by 37.8-75.4% within 60 days of treatment, and the root-galling index was reduced by 31.8-85.2%. Optimum tomato plant growth and maximum yields were observed in the 15 kg ha-1 treatment. The results indicated that a single basal application of thiacloprid could control M. incognita and B. tabaci and enhance tomato growth and yield.

  16. Inoculation of tomato plants with rhizobacteria enhances the performance of the phloem-feeding insect Bemisia tabaci

    PubMed Central

    Shavit, Roee; Ofek-Lalzar, Maya; Burdman, Saul; Morin, Shai

    2013-01-01

    In their natural environment, plants experience multiple biotic interactions and respond to this complexity in an integrated manner. Therefore, plant responses to herbivory are flexible and depend on the context and complexity in which they occur. For example, plant growth promoting rhizobacteria (PGPR) can enhance plant growth and induce resistance against microbial pathogens and herbivorous insects by a phenomenon termed induced systemic resistance (ISR). In the present study, we investigated the effect of tomato (Solanum lycopersicum) pre-inoculation with the PGPR Pseudomonas fluorescens WCS417r, on the performance of the generalist phloem-feeding insect Bemisia tabaci. Based on the ability of P. fluorescens WCS417r to prime for ISR against generalists chewing insects and necrotrophic pathogens, we hypothesized that pre-inoculated plants will strongly resist B. tabaci infestation. In contrast, we discovered that the pre-inoculation treatment increased the tomato plant suitability for B. tabaci which was emphasized both by faster developmental rate and higher survivability of nymph stages on pre-inoculated plants. Our molecular and chemical analyses suggested that the phenomenon is likely to be related to: (I) the ability of the bacteria to reduce the activity of the plant induced defense systems; (II) a possible manipulation by P. fluorescens of the plant quality (in terms of suitability for B. tabaci) through an indirect effect on the rhizosphere bacterial community. The contribution of our study to the pattern proposed for other belowground rhizobacteria and mycorrhizal fungi and aboveground generalist phloem-feeders is discussed. PMID:23964283

  17. Rapid accumulation and low degradation: key parameters of Tomato yellow leaf curl virus persistence in its insect vector Bemisia tabaci.

    PubMed

    Becker, Nathalie; Rimbaud, Loup; Chiroleu, Frédéric; Reynaud, Bernard; Thébaud, Gaël; Lett, Jean-Michel

    2015-12-02

    Of worldwide economic importance, Tomato yellow leaf curl virus (TYLCV, Begomovirus) is responsible for one of the most devastating plant diseases in warm and temperate regions. The DNA begomoviruses (Geminiviridae) are transmitted by the whitefly species complex Bemisia tabaci. Although geminiviruses have long been described as circulative non-propagative viruses, observations such as long persistence of TYLCV in B. tabaci raised the question of their possible replication in the vector. We monitored two major TYLCV strains, Mild (Mld) and Israel (IL), in the invasive B. tabaci Middle East-Asia Minor 1 cryptic species, during and after the viral acquisition, within two timeframes (0-144 hours or 0-20 days). TYLCV DNA was quantified using real-time PCR, and the complementary DNA strand of TYLCV involved in viral replication was specifically quantified using anchored real-time PCR. The DNA of both TYLCV strains accumulated exponentially during acquisition but remained stable after viral acquisition had stopped. Neither replication nor vertical transmission were observed. In conclusion, our quantification of the viral loads and complementary strands of both Mld and IL strains of TYLCV in B. tabaci point to an efficient accumulation and preservation mechanism, rather than to a dynamic equilibrium between replication and degradation.

  18. Rapid accumulation and low degradation: key parameters of Tomato yellow leaf curl virus persistence in its insect vector Bemisia tabaci

    PubMed Central

    Becker, Nathalie; Rimbaud, Loup; Chiroleu, Frédéric; Reynaud, Bernard; Thébaud, Gaël; Lett, Jean-Michel

    2015-01-01

    Of worldwide economic importance, Tomato yellow leaf curl virus (TYLCV, Begomovirus) is responsible for one of the most devastating plant diseases in warm and temperate regions. The DNA begomoviruses (Geminiviridae) are transmitted by the whitefly species complex Bemisia tabaci. Although geminiviruses have long been described as circulative non-propagative viruses, observations such as long persistence of TYLCV in B. tabaci raised the question of their possible replication in the vector. We monitored two major TYLCV strains, Mild (Mld) and Israel (IL), in the invasive B. tabaci Middle East-Asia Minor 1 cryptic species, during and after the viral acquisition, within two timeframes (0–144 hours or 0–20 days). TYLCV DNA was quantified using real-time PCR, and the complementary DNA strand of TYLCV involved in viral replication was specifically quantified using anchored real-time PCR. The DNA of both TYLCV strains accumulated exponentially during acquisition but remained stable after viral acquisition had stopped. Neither replication nor vertical transmission were observed. In conclusion, our quantification of the viral loads and complementary strands of both Mld and IL strains of TYLCV in B. tabaci point to an efficient accumulation and preservation mechanism, rather than to a dynamic equilibrium between replication and degradation. PMID:26625871

  19. Implication of the bacterial endosymbiont Rickettsia spp. in interactions of the whitefly Bemisia tabaci with tomato yellow leaf curl virus.

    PubMed

    Kliot, Adi; Cilia, Michelle; Czosnek, Henryk; Ghanim, Murad

    2014-05-01

    Numerous animal and plant viruses are transmitted by arthropod vectors in a persistent, circulative manner. Tomato yellow leaf curl virus (TYLCV) is transmitted by the sweet potato whitefly Bemisia tabaci. We report here that infection with Rickettsia spp., a facultative endosymbiont of whiteflies, altered TYLCV-B. tabaci interactions. A B. tabaci strain infected with Rickettsia acquired more TYLCV from infected plants, retained the virus longer, and exhibited nearly double the transmission efficiency compared to an uninfected B. tabaci strain with the same genetic background. Temporal and spatial antagonistic relationships were discovered between Rickettsia and TYLCV within the whitefly. In different time course experiments, the levels of virus and Rickettsia within the insect were inversely correlated. Fluorescence in situ hybridization analysis of Rickettsia-infected midguts provided evidence for niche exclusion between Rickettsia and TYLCV. In particular, high levels of the bacterium in the midgut resulted in higher virus concentrations in the filter chamber, a favored site for virus translocation along the transmission pathway, whereas low levels of Rickettsia in the midgut resulted in an even distribution of the virus. Taken together, these results indicate that Rickettsia, by infecting the midgut, increases TYLCV transmission efficacy, adding further insights into the complex association between persistent plant viruses, their insect vectors, and microorganism tenants that reside within these insects. Interest in bacterial endosymbionts in arthropods and many aspects of their host biology in agricultural and human health systems has been increasing. A recent and relevant studied example is the influence of Wolbachia on dengue virus transmission by mosquitoes. In parallel with our recently studied whitefly-Rickettsia-TYLCV system, other studies have shown that dengue virus levels in the mosquito vector are inversely correlated with bacterial load. Our work

  20. Establishment of papaya banker plant system for Parasitoid, Encarsia sophia (Hymenoptera: Aphilidae) against Bemisia tabaci (Hemiptera: Aleyrodidae) in greenhouse tomato production

    USDA-ARS?s Scientific Manuscript database

    The silverleaf whitefly, Bemisia tabaci biotype B (Gennadius) (Hemiptera:Aleyrodidae), is a key pest of tomato (Solanum lycopersicum L.) and other vegetable crops worldwide. To combat this pest, a non-crop banker plant system was evaluated that employs a parasitoid, Encarsia sophia (Girault & Dodd) ...

  1. Transcriptome analysis reveals a comprehensive insect resistance response mechanism in cotton to infestation by the phloem feeding insect Bemisia tabaci (whitefly)

    USDA-ARS?s Scientific Manuscript database

    The whitefly (Bemisia tabaci) causes tremendous damage to cotton production worldwide. However, very limited information is available about how plants perceive and defend themselves from this destructive pest. In this study, the transcriptomics differences between two cotton cultivars that exhibit e...

  2. Repellency of mustard (Brassica juncea) and arugula (Eruca sativa) plants, and plant oils against the sweetpotato whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae)

    USDA-ARS?s Scientific Manuscript database

    The sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is an economic complex of at least 36 cryptic species, comprising a highly polyphagous and serious pest of vegetable, fiber and ornamental crops. Sustainable alternative measures such as cultural controls can be effective ...

  3. Comparative transcriptome analysis in Bemisia tabaci in response to tomato yellow leaf curl virus and development of ribonucleic acid interference to manage whitefly-transmitted viruses

    USDA-ARS?s Scientific Manuscript database

    The whitefly, Bemisia tabaci transmits over 300 plant viruses, with the majority of them belonging to the Begomovirus genus. Begomoviruses are obligately transmitted to a wide range of agriculture crops, resulting in the loss of billions of dollars annually, while jeopardizing food security worldwid...

  4. Transcriptome analysis of Bemisia tabaci during tomato yellow leaf curl virus acquisition and ribonucleic acid interference to manage whitefly-transmitted viruses

    USDA-ARS?s Scientific Manuscript database

    Over 300 viruses are transmitted by the whitefly, Bemisia tabaci, with 90% of them belonging to the genus, Begomovirus. Begomoviruses are obligately transmitted by whiteflies to a wide range of agriculture crops, resulting in billions of dollars lost annually, while jeopardizing food security worldw...

  5. Pre shipping dip treatments using soap, natural oils, and Isaria fumosorosea: potential biopesticides for mitigating the spread of whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) invasive insects on ornamental plants

    USDA-ARS?s Scientific Manuscript database

    The whitefly Bemisia tabaci (Hemiptera: Aleyodidae) is an invasive insect pest affecting different crops including vegetables, fruits, cereals, and ornamentals. The efficacy of some products such as commercial soap, natural oils and Preferal® (based on the entomopathogenic fungus Isaria fumosorosea ...

  6. Gene transcript changes associated with Bemisia tabaci Biotype B induced tomato irregular ripening disorder identified using microarray technology and Q-RT-PCR

    USDA-ARS?s Scientific Manuscript database

    Tomato irregular ripening is a disorder manifested in the fruit as a result of silver leaf whitefly (otherwise known as the B biotype of Bemisia tabaci) feeding on leaf phloem of tomato. This physiological disorder has significant economic impact in commercial tomato production; however, little is k...

  7. Differential responses of the whitefly Bemisia tabaci symbionts to unfavorable low and high temperatures.

    PubMed

    Shan, Hong-Wei; Lu, Yu-Heng; Bing, Xiao-Li; Liu, Shu-Sheng; Liu, Yin-Quan

    2014-10-01

    The whitefly Bemisia tabaci complex contains many cryptic species, of which the Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED) are notorious invasive pests. In our field-collected whitefly samples, MEAM1 harbors an obligate primary symbiont "Candidatus Portiera aleyrodidarum" and two secondary symbionts, "Candidatus Hamiltonella defensa" and Rickettsia sp., whereas MED has only "Ca. Portiera aleyrodidarum" and "Ca. Hamiltonella defensa." Both "Ca. Portiera aleyrodidarum" and "Ca. Hamiltonella defensa" are intracellular endosymbionts residing in the bacteriomes, whereas Rickettsia sp. has a scattered distribution throughout the host body cavity. We examined responses of these symbionts to adverse temperatures as well as survival of the host insects. After cold treatment at 5 or 10 °C or heat treatment at 35 or 40 °C for 24 h, respectively, the infection rates of all symbionts were not significantly decreased based on diagnosis PCR. However, quantitative PCR assays indicated significant reduction of "Ca. Hamiltonella defensa" at 40 °C, and the reduction became greater as the duration increased. Compared with "Ca. Hamiltonella defensa," "Ca. Portiera aleyrodidarum" was initially less affected in the first day but then showed more rapid reduction at days 3-5. The density of Rickettsia sp. fluctuated but was not reduced significantly at 40 °C. Meanwhile, the mortality rates of the host whiteflies elevated rapidly as the duration of exposure to heat treatment increased. The differential responses of various symbionts to adverse temperatures imply complex interactions among the symbionts inside the same host insect and highlight the importance of taking the whole bacterial community into account in studies of symbioses.

  8. Genetic Networking of the Bemisia tabaci Cryptic Species Complex Reveals Pattern of Biological Invasions

    PubMed Central

    De Barro, Paul; Ahmed, Muhammad Z.

    2011-01-01

    Background A challenge within the context of cryptic species is the delimitation of individual species within the complex. Statistical parsimony network analytics offers the opportunity to explore limits in situations where there are insufficient species-specific morphological characters to separate taxa. The results also enable us to explore the spread in taxa that have invaded globally. Methodology/Principal Findings Using a 657 bp portion of mitochondrial cytochrome oxidase 1 from 352 unique haplotypes belonging to the Bemisia tabaci cryptic species complex, the analysis revealed 28 networks plus 7 unconnected individual haplotypes. Of the networks, 24 corresponded to the putative species identified using the rule set devised by Dinsdale et al. (2010). Only two species proposed in Dinsdale et al. (2010) departed substantially from the structure suggested by the analysis. The analysis of the two invasive members of the complex, Mediterranean (MED) and Middle East – Asia Minor 1 (MEAM1), showed that in both cases only a small number of haplotypes represent the majority that have spread beyond the home range; one MEAM1 and three MED haplotypes account for >80% of the GenBank records. Israel is a possible source of the globally invasive MEAM1 whereas MED has two possible sources. The first is the eastern Mediterranean which has invaded only the USA, primarily Florida and to a lesser extent California. The second are western Mediterranean haplotypes that have spread to the USA, Asia and South America. The structure for MED supports two home range distributions, a Sub-Saharan range and a Mediterranean range. The MEAM1 network supports the Middle East - Asia Minor region. Conclusion/Significance The network analyses show a high level of congruence with the species identified in a previous phylogenetic analysis. The analysis of the two globally invasive members of the complex support the view that global invasion often involve very small portions of the available

  9. Pymetrozine is hydroxylated by CYP6CM1, a cytochrome P450 conferring neonicotinoid resistance in Bemisia tabaci.

    PubMed

    Nauen, Ralf; Vontas, John; Kaussmann, Martin; Wölfel, Katharina

    2013-04-01

    Resistance to neonicotinoid insecticides such as imidacloprid in the cotton whitefly, Bemisia tabaci, is linked to its hydroxylation by constitutively overexpressed CYP6CM1, a cytochrome P450 enzyme. Here, an investigation was conducted to establish whether CYP6CM1 functionally expressed in Sf9 cells also detoxifies pymetrozine, a selective homopteran feeding blocker known to be cross-resistant to neonicotinoids in whiteflies. Incubation of pymetrozine with functionally expressed Bemisia CYP6CM1 and subsequent LC-MS/MS analysis revealed a rapid formation of two pymetrozine metabolites by hydroxylation of its heterocyclic 1,2,4-triazine ring system. Enzyme kinetics revealed a Km value of 5.9 ± 0.3 µM and a time-dependent depletion of pymetrozine. The known cross-resistance between imidacloprid, other neonicotinoid insecticides and pymetrozine in B. tabaci is most likely conferred by the very same detoxification mechanism, i.e. a monooxygenase-based hydroxylation mechanism linked to the overexpression of CYP6CM1. These insecticide chemistries should not be alternated in whitefly resistance management strategies. © 2012 Society of Chemical Industry.

  10. Inoculation of tomato plants (Solanum lycopersicum) with growth-promoting Bacillus subtilis retards whitefly Bemisia tabaci development.

    PubMed

    Valenzuela-Soto, José Humberto; Estrada-Hernández, María Gloria; Ibarra-Laclette, Enrique; Délano-Frier, John Paul

    2010-01-01

    Root inoculation of tomato (Solanum lycopersicum) plants with a Bacillus subtilis strain BEB-DN (BsDN) isolated from the rhizosphere of cultivated potato plants was able to promote growth and to generate an induced systemic resistance (ISR) response against virus-free Bemisia tabaci. Growth promotion was evident 3 weeks after inoculation. No changes in oviposition density, preference and nymphal number in the early stages of B. tabaci development were observed between BsDN-treated plants and control plants inoculated with a non-growth promoting Bs strain (PY-79), growth medium or water. However, a long-term ISR response was manifested by a significantly reduced number of B. tabaci pupae developing into adults in BsDN-treated plants. The observed resistance response appeared to be a combination of jasmonic acid (JA) dependent and JA-independent responses, since the BsDN-related retardation effect on B. tabaci development was still effective in the highly susceptible spr2 tomato mutants with an impaired capacity for JA biosynthesis. A screening of 244 genes, 169 of which were previously obtained from subtractive-suppressive-hybridization libraries generated from B. tabaci-infested plants suggested that the BsDN JA-dependent ISR depended on an anti-nutritive effect produced by the simultaneous expression of genes coding principally for proteases and proteinase inhibitors, whereas the JA-independent ISR observed in the spr2 background curiously involved the up-regulation of several photosynthetic genes, key components of the phenyl-propanoid and terpenoid biosynthetic pathways and of the Hsp90 chaperonin, which probably mediated pest resistance response(s), in addition to the down-regulation of pathogenesis and hypersensitive response genes.

  11. Only a minority of broad-range detoxification genes respond to a variety of phytotoxins in generalist Bemisia tabaci species

    PubMed Central

    Halon, Eyal; Eakteiman, Galit; Moshitzky, Pnina; Elbaz, Moshe; Alon, Michal; Pavlidi, Nena; Vontas, John; Morin, Shai

    2015-01-01

    Generalist insect can utilize two different modes for regulating their detoxification genes, the constitutive mode and the induced mode. Here, we used the Bemisia tabaci sibling species MEAM1 and MED, as a model system for studying constitutive and induced detoxification resistance and their associated tradeoffs. B. tabaci adults were allowed to feed through membranes for 24 h on diet containing only sucrose or sucrose with various phytotoxins. Quantitative real-time PCR analyses of 18 detoxification genes, indicated that relatively few transcripts were changed in both the MEAM1 and MED species, in response to the addition of phytotoxins to the diet. Induced transcription of detoxification genes only in the MED species, in response to the presence of indole-3-carbinol in the insect’s diet, was correlated with maintenance of reproductive performance in comparison to significant reduction in performance of the MEAM1 species. Three genes, COE2, CYP6-like 5 and BtGST2, responded to more than one compound and were highly transcribed in the insect gut. Furthermore, functional assays showed that the BtGST2 gene encodes a protein capable of interacting with both flavonoids and glucosinolates. In conclusion, several detoxification genes were identified that could potentially be involved in the adaptation of B. tabaci to its host plants. PMID:26655836

  12. [Effects of the volatiles from different tomato varieties on host selection behavior of B-biotype Bemisia tabaci].

    PubMed

    Zhao, Yan-Qun; Zhao, Jin-Rui; Mao, Li-Juan; Shi, Zu-Hua

    2012-09-01

    By the methods of headspace solid-phase micro extraction and gas chromatography-mass spectrometry, and using Y-type olfactometer, this paper identified the volatiles from six tomato varieties (Zheza 809, Zheza 203, Hezuo 903, Kate No. 1, Huangtuoyan, and Jinfei), and bio-assayed the olfactory responses of female B-biotype Bemisia tabaci to the tomato plants and their released volatiles. Thirteen kinds of compounds in the volatiles collected from the six tomato varieties were identified, among which, terpenoids were the main components. However, the compositions and contents of the volatiles differed with tomato varieties. (+)-3-carene and beta-caryophyllene showed stronger repellency than other terpenoids to B-type B. tabaci. B-type B. tabaci showed the lowest preference to the tomato varieties such as Zheza 809 and Zheza 203 which contained more kinds of terpenoids and had higher proportion of terpenoids in the volatiles, and showed the greatest preference to the varieties like Huangtuoyan and Jinfei which contained fewer kinds of terpenoids and had lower proportion of terpenoids in the volatiles.

  13. High Level of Nitrogen Makes Tomato Plants Releasing Less Volatiles and Attracting More Bemisia tabaci (Hemiptera: Aleyrodidae)

    PubMed Central

    Islam, Md. Nazrul; Hasanuzzaman, Abu Tayeb Mohammad; Zhang, Zhan-Feng; Zhang, Yi; Liu, Tong-Xian

    2017-01-01

    Tomato (Solanum lycopersicum) production is seriously hampered by the infestation of the sweetpotato whitefly, Bemisia tabaci MEAM 1 (Middle East-Asia Minor 1). The infestation behavior of the whiteflies could be affected by the quantity of plant released volatile organic compounds (VOCs) related to nitrogen concentrations of the plant. In this study, we determined the infestation behavior of B. tabaci to the tomato plants that produced different levels of VOCs after application of different levels of nitrogen with a wind tunnel and an olfactometer. We also analyzed the VOCs released from nitrogen-treated tomato plants using solid phase microextraction and gas chromatography-mass spectrometry. The results revealed that the production of eight VOCs (β-pinene, (+)-4-carene, α-terpinene, p-cymene, β-phellandrene, α-copaene, β-caryophyllene, and α-humulene) was reduced after the plants were treated with high levels of nitrogen. However, more whiteflies were attracted to the tomato plants treated with high levels of nitrogen than to the plants treated with normal or below normal levels of nitrogen. These results clearly indicated that nitrogen can change the quality and quantity of tomato plant volatile chemicals, which play important roles in B. tabaci host plant selection. PMID:28408917

  14. Differential expression patterns among heat-shock protein genes and thermal responses in the whitefly Bemisia tabaci (MEAM 1).

    PubMed

    Díaz, Fernando; Orobio, Rony F; Chavarriaga, Paul; Toro-Perea, Nelson

    2015-08-01

    There is convincing evidence that heat-shock proteins (HSP) are upregulated by stress conditions in insects; however, the relative contribution of each HSP gene to the heat-shock response remains unclear. Here we considered the whitefly Bemisia tabaci (MEAM 1), a phloem feeder and invasive species whose molecular stress response is an important mechanism for overcoming heat stress. We assessed the expression of the hsp23, 40, 70 and 90 genes at the mRNA level when submitted to heat shocks of 40 and 44°C/1h (control at 25°C). For this, we evaluated a set of available and suitable reference genes in order to perform data normalization using the real-time polymerase chain reaction (qRT-PCR) technique, and then confirmed the production of HSP70 protein based on Western blot. Results were compared with the hardening capacity of B. tabaci, measured by fitness components as a response to heat shocks, using 40°C as the induction temperature. Three of the four genes (hsp23, 70 and 90) were upregulated by heat stress at mRNA, showing differential expression patterns. Hsp70 expression was confirmed at the protein level. Hardening significantly increased fitness following heat stress, suggesting that HSPs may contribute to hardening capacity in B. tabaci. Potential role of each gene in the heat-shock response for whiteflies is discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Transcriptome profiling of the whitefly Bemisia tabaci reveals stage-specific gene expression signatures for thiamethoxam resistance.

    PubMed

    Yang, N; Xie, W; Jones, C M; Bass, C; Jiao, X; Yang, X; Liu, B; Li, R; Zhang, Y

    2013-10-01

    Bemisia tabaci has developed high levels of resistance to many insecticides including the neonicotinoids and there is strong evidence that for some compounds resistance is stage-specific. To investigate the molecular basis of B. tabaci resistance to the neonicotinoid thiamethoxam we used a custom whitefly microarray to compare gene expression in the egg, nymph and adult stages of a thiamethoxam-resistant strain (TH-R) with a susceptible strain (TH-S). Gene ontology and bioinformatic analyses revealed that in all life stages many of the differentially expressed transcripts encoded enzymes involved in metabolic processes and/or metabolism of xenobiotics. Several of these are candidate resistance genes and include the cytochrome P450 CYP6CM1, which has been shown to confer resistance to several neonicotinoids previously, a P450 belonging to the Cytochrome P450s 4 family and a glutathione S-transferase (GST) belonging to the sigma class. Finally several ATP-binding cassette transporters of the ABCG subfamily were highly over-expressed in the adult stage of the TH-R strain and may play a role in resistance by active efflux. Here, we evaluated both common and stage-specific gene expression signatures and identified several candidate resistance genes that may underlie B. tabaci resistance to thiamethoxam.

  16. Location of Symbionts in the Whitefly Bemisia tabaci Affects Their Densities during Host Development and Environmental Stress

    PubMed Central

    Su, Qi; Xie, Wen; Wang, Shaoli; Wu, Qingjun; Ghanim, Murad; Zhang, Youjun

    2014-01-01

    Bacterial symbionts often enhance the physiological capabilities of their arthropod hosts and enable their hosts to expand into formerly unavailable niches, thus leading to biological diversification. Many arthropods, including the worldwide invasive whitefly Bemisia tabaci, have individuals simultaneously infected with symbionts of multiple genera that occur in different locations in the host. This study examined the population dynamics of symbionts that are located in different areas within B. tabaci. While densities of Portiera and Hamiltonella (which are located in bacteriocytes) appeared to be well-regulated during host development, densities of Rickettsia (which are not located in bacteriocytes) were highly variable among individual hosts during host development. Host mating did not significantly affect symbiont densities. Infection by Tomato yellow leaf curl virus did not affect Portiera and Hamiltonella densities in either sex, but increased Rickettsia densities in females. High and low temperatures did not affect Portiera and Hamiltonella densities, but low temperature (15°C) significantly suppressed Rickettsia densities whereas high temperature (35°C) had little effect on Rickettsia densities. The results are consistent with the view that the population dynamics of bacterial symbionts in B. tabaci are regulated by symbiont location within the host and that the regulation reflects adaptation between the bacteria and insect. PMID:24632746

  17. Effects of high-gossypol cotton on the development and reproduction of Bemisia tabaci (Hemiptera: Aleyrodidae) MEAM1 cryptic species.

    PubMed

    Guo, Jian-Ying; Wu, Gang; Wan, Fang-Hao

    2013-06-01

    Use of plant secondary metabolic compounds is an important method for insect pest control. In this study, the survival, development, and reproduction of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) MEAM1 cryptic species were compared over two consecutive generations on three cotton cultivars of different gossypol levels. Both cotton cultivar and generation significantly affected the fitness of the whitefly. In both generations, the immature development times on the low-gossypol cultivar ZMS13 were significantly longer than those on the high-gossypol cultivar M9101 or medium-gossypol cultivar HZ401. The female fecundity and rate of population increase of the whitefly ranked in the following order: ZMS13 > HZ401 > M9101. On each cultivar, the immature development time was shorter and the immature survival rate was higher in the second generation than those in the first generation. Rate of increase was also higher in the second generation. These results demonstrated that the fitness of B. tabaci MEAM1 cryptic species on the low-gossypol cotton cultivar ZMS13 was higher than that on the medium- or high-gossypol cultivar. The comparison of the life histories of B. tabaci MEAM1 cryptic species on different cotton varieties is important for the development of an integrated pest management program of the whitefly by using plant secondary metabolic compounds.

  18. Competitive ability and fitness differences between two introduced populations of the invasive whitefly Bemisia tabaci Q in China.

    PubMed

    Fang, Yi-Wei; Liu, Ling-Yun; Zhang, Hua-Li; Jiang, De-Feng; Chu, Dong

    2014-01-01

    Our long-term field survey revealed that the Cardinium infection rate in Bemisia tabaci Q (also known as biotype Q) population was low in Shandong, China over the past few years. We hypothesize that (1) the Cardinium-infected (C+) B. tabaci Q population cannot efficiently compete with the Cardinium-uninfected (C-) B. tabaci Q population; (2) no reproductive isolation may have occurred between C+ and C-; and (3) the C- population has higher fitness than the C+ population. To reveal the differences in competitive ability and fitness between the two introduced populations (C+ and C-), competition between C+ and C- was examined over several generations. Subsequently, the reproductive isolation between C+ and C- was studied by crossing C+ with C- individuals, and the fitnesses of C+ and C- populations were compared using a two-sex life table method. Our results demonstrate that the competitive ability of the C+ whiteflies was weaker than that of C-. There is that no reproductive isolation occurred between the two populations and the C- population had higher fitness than the C+ population. The competitive ability and fitness differences of two populations may explain why C- whitefly populations have been dominant during the past few years in Shandong, China. However, the potential role Cardinium plays in whitefly should be further explored.

  19. Transcriptome profiling of the whitefly Bemisia tabaci reveals stage-specific gene expression signatures for thiamethoxam resistance

    PubMed Central

    Yang, N; Xie, W; Jones, CM; Bass, C; Jiao, X; Yang, X; Liu, B; Li, R; Zhang, Y

    2013-01-01

    Bemisia tabaci has developed high levels of resistance to many insecticides including the neonicotinoids and there is strong evidence that for some compounds resistance is stage-specific. To investigate the molecular basis of B. tabaci resistance to the neonicotinoid thiamethoxam we used a custom whitefly microarray to compare gene expression in the egg, nymph and adult stages of a thiamethoxam-resistant strain (TH-R) with a susceptible strain (TH-S). Gene ontology and bioinformatic analyses revealed that in all life stages many of the differentially expressed transcripts encoded enzymes involved in metabolic processes and/or metabolism of xenobiotics. Several of these are candidate resistance genes and include the cytochrome P450 CYP6CM1, which has been shown to confer resistance to several neonicotinoids previously, a P450 belonging to the Cytochrome P450s 4 family and a glutathione S-transferase (GST) belonging to the sigma class. Finally several ATP-binding cassette transporters of the ABCG subfamily were highly over-expressed in the adult stage of the TH-R strain and may play a role in resistance by active efflux. Here, we evaluated both common and stage-specific gene expression signatures and identified several candidate resistance genes that may underlie B. tabaci resistance to thiamethoxam. PMID:23889345

  20. Competitive Ability and Fitness Differences between Two Introduced Populations of the Invasive Whitefly Bemisia tabaci Q in China

    PubMed Central

    Fang, Yi-Wei; Liu, Ling-Yun; Zhang, Hua-Li; Jiang, De-Feng; Chu, Dong

    2014-01-01

    Background Our long-term field survey revealed that the Cardinium infection rate in Bemisia tabaci Q (also known as biotype Q) population was low in Shandong, China over the past few years. We hypothesize that (1) the Cardinium-infected (C+) B. tabaci Q population cannot efficiently compete with the Cardinium-uninfected (C−) B. tabaci Q population; (2) no reproductive isolation may have occurred between C+ and C−; and (3) the C− population has higher fitness than the C+ population. Methodology and Results To reveal the differences in competitive ability and fitness between the two introduced populations (C+ and C−), competition between C+ and C− was examined over several generations. Subsequently, the reproductive isolation between C+ and C− was studied by crossing C+ with C− individuals, and the fitnesses of C+ and C− populations were compared using a two-sex life table method. Our results demonstrate that the competitive ability of the C+ whiteflies was weaker than that of C−. There is that no reproductive isolation occurred between the two populations and the C− population had higher fitness than the C+ population. Conclusion The competitive ability and fitness differences of two populations may explain why C− whitefly populations have been dominant during the past few years in Shandong, China. However, the potential role Cardinium plays in whitefly should be further explored. PMID:24945699

  1. Mixed release of two parasitoids and a polyphagous ladybird as a potential strategy to control the tobacco whitefly Bemisia tabaci.

    PubMed

    Tan, Xiaoling; Hu, Nana; Zhang, Fan; Ramirez-Romero, Ricardo; Desneux, Nicolas; Wang, Su; Ge, Feng

    2016-06-17

    A mixed species release of parasitoids is used to suppress outbreaks of tobacco whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae); however, this biocontrol may be inhibited by interspecific interactions. We investigated the effects of mixed releases of natural enemies of B. tabaci on predation rates, parasite performance and adult parasitoid emergence under greenhouse conditions. We tested the polyphagous predatory ladybird Harmonia axyridis (Coleoptera: Coccinellidae) and two whitefly-specific parasitoids, namely Encarsia formosa and Encarsia sophia (both, Hymenoptera: Aphelinidae). Harmonia axyridis exhibited the lowest rates of predation when released with each parasitoid than with both parasitoid species together and showed a significant preference for non-parasitized nymphs as prey. Both E. formosa and E. sophia parasitized more B. tabaci when released with the ladybird than when the wasps were released either alone or mixed with the other parasitoid. We also found that the presence of H. axyridis significantly reduced adult parasitoid emergence; the highest rate of adult emergence was obtained with parasitoids released alone. Our results indicate that different combinations of natural enemies can influence observed rates of predation, parasitism, and parasitoid emergence. Therefore, the combination of natural enemies to be used for a particular biological control program should depend on the specific objectives.

  2. Differing Behavioural Responses of Bemisia tabaci MEAM1 and MED to Cabbage Damaged by Conspecifics and Heterospecifics

    PubMed Central

    Kong, Hailong; Zeng, Yang; Xie, Wen; Wang, Shaoli; Wu, Qingjun; Jiao, Xiaoguo; Xu, Baoyun; Zhang, Youjun

    2016-01-01

    The whitefly Bemisia tabaci is a serious pest with an extensive host range. Previous research has shown that B. tabaci is a species complex with many cryptic species or biotypes and that the two most important species are MEAM1 (Middle East-Minor Asia 1) and MED (Mediterranean genetic group). MEAM1 and MED are known to differ in their preference for cabbage, Brassica oleracea, as a host plant, however, the mechanism underlying this preference is unknown. In the current study, a host choice experiment showed that MED prefers to settle and oviposit on undamaged cabbage plants rather than MED-damaged cabbage plants. However, MEAM1 prefers MED-damaged cabbage plants to undamaged plants and does not exhibit a significant preference for undamaged or MEAM1-damaged cabbage plants. On the basis of gas chromatography-mass spectrometry (GC-MS) analysis, the following volatiles were released in larger quantities from Q-damaged cabbage plants than from undamaged plants: 2-ethyl-1-hexanol, benzenemethanol, (E)-2-decenol, benzaldehyde, nonanal, acetic acid geraniol ester, 4-hydroxy-4-methyl-2-pentanone, decane, and α-longipinene. Only one volatile, 4-hydroxy-4-methyl-2-pentanone, was released in greater quantities from MEAM1-damaged cabbage plants than from undamaged plants. Our results suggest that differences in herbivore-induced host volatile release may help explain the differences between the preference of B. tabaci MEAM1 and MED for cabbage as a host. PMID:27731417

  3. Mixed release of two parasitoids and a polyphagous ladybird as a potential strategy to control the tobacco whitefly Bemisia tabaci

    PubMed Central

    Tan, Xiaoling; Hu, Nana; Zhang, Fan; Ramirez-Romero, Ricardo; Desneux, Nicolas; Wang, Su; Ge, Feng

    2016-01-01

    A mixed species release of parasitoids is used to suppress outbreaks of tobacco whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae); however, this biocontrol may be inhibited by interspecific interactions. We investigated the effects of mixed releases of natural enemies of B. tabaci on predation rates, parasite performance and adult parasitoid emergence under greenhouse conditions. We tested the polyphagous predatory ladybird Harmonia axyridis (Coleoptera: Coccinellidae) and two whitefly-specific parasitoids, namely Encarsia formosa and Encarsia sophia (both, Hymenoptera: Aphelinidae). Harmonia axyridis exhibited the lowest rates of predation when released with each parasitoid than with both parasitoid species together and showed a significant preference for non-parasitized nymphs as prey. Both E. formosa and E. sophia parasitized more B. tabaci when released with the ladybird than when the wasps were released either alone or mixed with the other parasitoid. We also found that the presence of H. axyridis significantly reduced adult parasitoid emergence; the highest rate of adult emergence was obtained with parasitoids released alone. Our results indicate that different combinations of natural enemies can influence observed rates of predation, parasitism, and parasitoid emergence. Therefore, the combination of natural enemies to be used for a particular biological control program should depend on the specific objectives. PMID:27312174

  4. DNA Barcoding of Bemisia tabaci Complex (Hemiptera: Aleyrodidae) Reveals Southerly Expansion of the Dominant Whitefly Species on Cotton in Pakistan

    PubMed Central

    Ashfaq, Muhammad; Hebert, Paul D. N.; Mirza, M. Sajjad; Khan, Arif M.; Mansoor, Shahid; Shah, Ghulam S.; Zafar, Yusuf

    2014-01-01

    Background Although whiteflies (Bemisia tabaci complex) are an important pest of cotton in Pakistan, its taxonomic diversity is poorly understood. As DNA barcoding is an effective tool for resolving species complexes and analyzing species distributions, we used this approach to analyze genetic diversity in the B. tabaci complex and map the distribution of B. tabaci lineages in cotton growing areas of Pakistan. Methods/Principal Findings Sequence diversity in the DNA barcode region (mtCOI-5′) was examined in 593 whiteflies from Pakistan to determine the number of whitefly species and their distributions in the cotton-growing areas of Punjab and Sindh provinces. These new records were integrated with another 173 barcode sequences for B. tabaci, most from India, to better understand regional whitefly diversity. The Barcode Index Number (BIN) System assigned the 766 sequences to 15 BINs, including nine from Pakistan. Representative specimens of each Pakistan BIN were analyzed for mtCOI-3′ to allow their assignment to one of the putative species in the B. tabaci complex recognized on the basis of sequence variation in this gene region. This analysis revealed the presence of Asia II 1, Middle East-Asia Minor 1, Asia 1, Asia II 5, Asia II 7, and a new lineage “Pakistan”. The first two taxa were found in both Punjab and Sindh, but Asia 1 was only detected in Sindh, while Asia II 5, Asia II 7 and “Pakistan” were only present in Punjab. The haplotype networks showed that most haplotypes of Asia II 1, a species implicated in transmission of the cotton leaf curl virus, occurred in both India and Pakistan. Conclusions DNA barcodes successfully discriminated cryptic species in B. tabaci complex. The dominant haplotypes in the B. tabaci complex were shared by India and Pakistan. Asia II 1 was previously restricted to Punjab, but is now the dominant lineage in southern Sindh; its southward spread may have serious implications for cotton plantations in this region. PMID

  5. Activation of the Phenylpropanoid Pathway in Nicotiana tabacum Improves the Performance of the Whitefly Bemisia tabaci via Reduced Jasmonate Signaling

    PubMed Central

    Alon, Michal; Malka, Osnat; Eakteiman, Galit; Elbaz, Moshe; Moyal Ben Zvi, Michal; Vainstein, Alexander; Morin, Shai

    2013-01-01

    Background Phloem-feeding insects can manipulate plant-induced resistance and are able to suppress effective jasmonic acid/ethylene (JA/ET) defenses by the induction of inefficient salicylic acid (SA) based responses. As a result, activation of the phenylpropanoid biosynthesis pathway in transgenic plants is anticipated to cause complex interactions between phloem-feeding insects and their host plants due to predicted contradiction between two defense forces: the toxicity of various phenylpropanoids and the accumulation of SA via a branch of the activated pathway. Methodology/Principal Findings Here, we investigated the effect of activating the phenylpropanoids pathway in Nicotiana tabacum, by over-expression of the PAP1 transcription factor, on the whitefly Bemisia tabaci, a phloem-feeding insect model. Our performance assays indicated that the over-expression made the transgenic plants a more suitable host for B. tabaci than wild-type (WT) plants, although these plants accumulated significantly higher levels of flavonoids. Transcription analyses of indicator genes in the SA (PR1a) and JA/ET (ERF1, COI1 and AOC) pathways followed by quantification of the SA and JA hormone levels, indicated that B. tabaci infestation periods longer than 8 hours, caused higher levels of activity of SA signaling in transgenic plants and higher levels of JA/ET signaling in WT plants. Conclusions/Significance Taken together, these results emphasize the important role JA/ET-induced defenses play in protecting plants from successful infestation by B. tabaci and likely other phloem-feeding insects. It also indicates the necessity of phloem feeders to suppress these defenses for efficient utilization of plant hosts. Our data also indicate that the defensive chemistry produced by the phenylpropanoids pathway has only a minor effect on the insect fitness. PMID:24204646

  6. Cross-resistance study and biochemical mechanisms of thiamethoxam resistance in B-biotype Bemisia tabaci (Hemiptera: Aleyrodidae).

    PubMed

    Feng, Yuntao; Wu, Qingjun; Wang, Shaoli; Chang, Xiaoli; Xie, Wen; Xu, Baoyun; Zhang, Youjun

    2010-03-01

    B-biotype Bemisia tabaci (Gennadius) has invaded China over the past two decades. To understand the risks and to determine possible mechanisms of resistance to thiamethoxam in B. tabaci, a resistant strain was selected in the laboratory. Cross-resistance and the biochemical mechanisms of thiamethoxam resistance were investigated in the present study. A 66.3-fold thiamethoxam-resistant B. tabaci strain (TH-R) was established after selection for 36 generations. Compared with the susceptible strain (TH-S), the selected TH-R strain showed obvious cross-resistance to imidacloprid (47.3-fold), acetamiprid (35.8-fold), nitenpyram (9.99-fold), abamectin (5.33-fold) and carbosulfan (4.43-fold). No cross-resistance to fipronil, chlorpyrifos or deltamethrin was seen. Piperonyl butoxide (PBO) and triphenyl phosphate (TPP) exhibited significant synergism on thiamethoxam effects in the TH-R strain (3.14- and 2.37-fold respectively). However, diethyl maleate (DEM) did not act synergistically with thiamethoxam. Biochemical assays showed that cytochrome P450 monooxygenase activities increased 1.21- and 1.68-fold respectively, and carboxylesterase activity increased 2.96-fold in the TH-R strain. However, no difference was observed for glutathione S-transferase between the two strains. B-biotype B. tabaci develops resistance to thiamethoxam. Cytochrome P450 monooxygenase and carboxylesterase appear to be responsible for the resistance. Reasonable resistance management that avoids the use of cross-resistance insecticides may delay the development of resistance to thiamethoxam in this species.

  7. Multiple generation effects of high temperature on the development and fecundity of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) biotype B.

    PubMed

    Guo, Jian-Ying; Cong, Lin; Wan, Fang-Hao

    2013-08-01

    Insects are ectotherms and their ability to resist temperature stress is limited. The immediate effects of sub-lethal heat stress on insects are well documented, but longer-term effects of such stresses are rarely reported. In this study, survival, development and reproduction of the whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) biotype B, were compared over five consecutive generations at 27, 31 and 35 °C and for one generation at 37 °C. Both temperature and generation significantly affected the fitness of the whitefly. These impacts were more dramatic with increasing generations and temperatures. Among the experimental temperatures, the most favorable for development and reproduction were 27 °C and 31 °C. At 27 °C, survival, development and fecundity were all stable over these five generations. At 31 °C, immature survival rate was the highest in the fifth generation, but female fecundities decreased in the fourth and fifth generations. At 35 °C, egg hatching rate, immature survival rate and female fecundity decreased significantly in the fourth and fifth generations. At 37 °C, survival of B. tabaci was not adversely affected, but female fecundity at 37 °C was less than 10% of that at 27 °C or 31 °C. These results demonstrate that the lethal high temperature for B. tabaci is over 37 °C, and the whitefly population continued expanding in the five generations at 35 °C. The ability of B. tabaci biotype B to survive high temperature stress will play an important role in its population extension under global warming. © 2012 The Authors Insect Science © 2012 Institute of Zoology, Chinese Academy of Sciences.

  8. Assessment of Potential Sublethal Effects of Various Insecticides on Key Biological Traits of The Tobacco Whitefly, Bemisia tabaci

    PubMed Central

    He, Yuxian; Zhao, Jianwei; Zheng, Yu; Weng, Qiyong; Biondi, Antonio; Desneux, Nicolas; Wu, Kongming

    2013-01-01

    The tobacco whitefly Bemisia tabaci is one of the most devastating pests worldwide. Current management of B. tabaci relies upon the frequent applications of insecticides. In addition to direct mortality by typical acute toxicity (lethal effect), insecticides may also impair various key biological traits of the exposed insects through physiological and behavioral sublethal effects. Identifying and characterizing such effects could be crucial for understanding the global effects of insecticides on the pest and therefore for optimizing its management in the crops. We assessed the effects of sublethal and low-lethal concentrations of four widely used insecticides on the fecundity, honeydew excretion and feeding behavior of B. tabaci adults. The probing activity of the whiteflies feeding on treated cotton seedlings was recorded by an Electrical Penetration Graph (EPG). The results showed that imidacloprid and bifenthrin caused a reduction in phloem feeding even at sublethal concentrations. In addition, the honeydew excretions and fecundity levels of adults feeding on leaf discs treated with these concentrations were significantly lower than the untreated ones. While, sublethal concentrations of chlorpyrifos and carbosulfan did not affect feeding behavior, honeydew excretion and fecundity of the whitefly. We demonstrated an antifeedant effect of the imidacloprid and bifenthrin on B. tabaci, whereas behavioral changes in adults feeding on leaves treated with chlorpyrifos and carbosulfan were more likely caused by the direct effects of the insecticides on the insects' nervous system itself. Our results show that aside from the lethal effect, the sublethal concentration of imidacloprid and bifenthrin impairs the phloem feeding, i.e. the most important feeding trait in a plant protection perspective. Indeed, this antifeedant property would give these insecticides potential to control insect pests indirectly. Therefore, the behavioral effects of sublethal concentrations of

  9. Densities of Eggs and Nymphs and Percent Parasitism of Bemisia tabaci (Hemiptera: Aleyrodidae) on Common Weeds in West Central Florida

    PubMed Central

    Smith, Hugh A.; Nagle, Curtis A.; Evans, Gregory A.

    2014-01-01

    The density of eggs and nymphs of Bemisia tabaci (Gennadius) biotype B and the percent parasitism of the nymphs were measured from specimens collected on nine species of weeds, commonly found in west central Florida during the spring and summer of 2012 and 2013. The weeds were direct seeded in 2012 and grown as transplants in 2013 for Randomized Complete Block design experiments. The leaf area of each whole-plant sample was measured and the B. tabaci density parameters were converted to numbers per 100 cm2. In June and July, 2013, whole-plant samples became too large to examine entirely, thus a representative portion of a plant totaling about 1000 cm2 was sampled. Egg and nymph densities and percent parasitism varied greatly among weed species, and were higher overall in 2012 than in 2013. The highest densities of eggs and nymphs were measured on Abutilon theophrasti, Cassia obtusifolia and Emilia fosbergii each year. Lower densities of immature B. tabaci were measured on most dates for Amaranthus retroflexus, Bidens alba, Ipomoea lacunosa, Sesbania exaltata and Sida acuta. Nymph to egg ratios of 1:4 were observed on A. theophrasti and S. exaltata in 2012, while less than one nymph per ten eggs was observed overall on A. retroflexus, E. fosbergii and I. lacunosa. In 2012, parasitism rates of 32.3% were measured for B. alba, 23.4% for C. obtusifolia and 17.5% for S. acuta. Of the 206 parasitoids reared out over two seasons, 96.6% were Encarsia spp. and the remainder Eretmocerus spp. The role of weeds in managing B. tabaci is discussed. PMID:26462945

  10. Implication of the Whitefly Bemisia tabaci Cyclophilin B Protein in the Transmission of Tomato yellow leaf curl virus

    PubMed Central

    Kanakala, Surapathrudu; Ghanim, Murad

    2016-01-01

    Tomato yellow leaf curl virus (TYLCV) is a single-stranded (ssDNA) begomoviruses that causes severe damage to tomato and several other crops worldwide. TYLCV is exclusively transmitted by the sweetpotato whitefly, Bemisia tabaci in a persistent circulative and propagative manner. Previous studies have shown that the transmission, retention, and circulation of TYLCV in its vector involves interaction with insect and endosymbiont proteins, which aid in the transmission of the virus, or have a protective role in response to the presence of the virus in the insect body. However, only a low number of such proteins have been identified. Here, the role of B. tabaci Cyclophilin B (CypB) in the transmission of TYLCV protein was investigated. Cyclophilins are a large family of cellular prolyl isomerases that have many molecular roles including facilitating protein-protein interactions in the cell. One cyclophilin protein has been implicated in aphid-luteovirus interactions. We demonstrate that the expression of CypB from B. tabaci is altered upon TYLCV acquisition and retention. Further experiments used immunocapture-PCR and co-immunolocalization and demonstrated a specific interaction and colocalization between CypB and TYLCV in the the midgut, eggs, and salivary glands. Membrane feeding of anti-CypB antibodies and TYLCV-infected plants showed a decrease in TYLCV transmission, suggesting a critical role that CypB plays in TYLCV transmission. Further experiments, which used membrane feeding with the CypB inhibitor Cyclosporin A showed decrease in CypB-TYLCV colocalization in the midgut and virus transmission. Altogether, our results indicate that CypB plays an important role in TYLCV transmission by B. tabaci. PMID:27895657

  11. Analysis of Species, Subgroups, and Endosymbionts of Bemisia tabaci (Hemiptera: Aleyrodidae) From Southwestern Cotton Fields in Turkey.

    PubMed

    Karut, Kamil; Mete Karaca, M; Döker, Ismail; Kazak, Cengiz

    2017-08-01

    Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is one of the most important insect pests worldwide including Turkey. Although there are substantial data regarding species composition of Turkish B. tabaci populations, the situation is still not clear and further investigations are needed. Therefore, in this study, species and subgroups of B. tabaci collected from cotton fields in southwestern part of Turkey (Antalya, Aydın, Denizli, and Muğla) were determined using microsatellite analysis, AluI-based mtCOI polymerase chain reaction-random length polymorphism, and sequencing. Secondary endosymbionts were also determined using diagnostic species-specific PCR. Middle East Asia Minor 1 (MEAM1), Mediterranean (MED) Q1, and MED Q2 were the species and subgroups found in this study. The MED species (85.3%) were found to be more dominant than MEAM1. Species status of B. tabaci varied depending on the location. Although all samples collected from Aydın were found to be Q1, three species and subgroups were found in Muğla. Secondary endosymbionts varied according to species and subgroups. Arsenophonus was found only from Q2, while Hamiltonella was detected in MEAM1 and Q1. In addition, high Rickettsia and low Wolbachia infections were detected in MEAM1 and Q1 populations, respectively. In conclusion, for the first time, we report the presence and symbiotic communities of Q1 from Turkey. We also found that the symbiont complement of the Q1 is more congruent with Q1 from Greece than other regions of the world, which may have some interesting implications for movement of this invasive subgroup. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  12. Effects of Heat Shock on Survival and Reproduction of Two Whitefly Species, Trialeurodes vaporariorum and Bemisia tabaci Biotype B

    PubMed Central

    Cui, Xuhong; Wan, Fanghao; Xie, Ming; Liu, Tongxian

    2008-01-01

    The effects of heat shock on survival and reproduction of two whitefly species, Trialeurodes vaporariorum (Westwood) and Bemisia tabaci (Gennadius) biotype B (Homoptera: Aleyrodidae), were compared in the laboratory. Whitefly adults were exposed to 26 (control), 37, 39, 41, 43 and 45°C for 1 hour, and were then maintained at 26°C. Adult survival was significantly affected when they were exposed at 41°C or higher for B. tabaci or 39°C or higher for T. vaporariorum. All males of T. vaporariorum were killed at 45°C. In both whitefly species, females were more tolerant to high temperatures at 39°C or higher than males. Female fecundity was not significantly different when B. tabaci adults were heat-shocked at all temperatures. In contrast, the fecundity of T. vaporariorum females declined with the increase of temperature, and only a few eggs were oviposited at 43°C. Survival or hatch rates of the F1 nymphs of both whitefly species declined as heat-shock temperature increased, and no T. vaporariorum nymphs were hatched at 43°C. Similarly, percentages of F1 offspring developing to adults for both whitefly species also declined as the heat-shock temperature increased. Sex ratios of the F1 offspring were not significantly affected for T. vaporariorum but were slightly affected for B. tabaci at 43 and 45°C. The significance of heat shock in relation to dispersal, distribution and population dynamics of the two whitefly species is discussed.

  13. Lethal and Inhibitory Activities of Plant-Derived Essential Oils Against Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) Biotype B in Tomato.

    PubMed

    Fanela, T L M; Baldin, E L L; Pannuti, L E R; Cruz, P L; Crotti, A E M; Takeara, R; Kato, M J

    2016-04-01

    The silverleaf whitefly Bemisia tabaci (Genn.) biotype B (Hemiptera: Aleyrodidae) is one of the most severe tomato pests in the world. The damage caused by this insect may compromise up to 100% of crop production, and management of this pest has relied on spraying of synthetic insecticides. However, due to the environmental issues associated with this practice, alternative methods such as the use of botanical pesticides are now used as a strategy of integrated pest management (IPM). We evaluated the effects of essential oils of five plant species on B. tabaci biotype B in tomato and demonstrate that the essential oils (0.5%) of Piper callosum (PC-EO), Adenocalymma alliaceum (AA-EO), Pelargonium graveolens (PG-EO), and Plectranthus neochilus (PN-EO) inhibit the settlement and oviposition of B. tabaci biotype B adults in tomato plants. In fumigation tests, A. alliaceum (AA-EO) at 0.4 μL/L of air after 72 h and 0.1 μL/L of air after 6 h was the most effective against nymphs and adults of B. tabaci biotype B, respectively. The major chemical constituents of PC-EO were identified as being safrole (29.3%), α-pinene (19.2%), and β-pinene (14.3%), whereas diallyl trisulfide (66.9%) and diallyl disulfide (23.3%) were the major compounds identified in AA-EO. This is the first report on the reduction of oviposition by the use of P. callosum (PC-EO) and A. alliaceum (AA-EO). In addition, the fumigant effect of A. alliaceum (AA-EO) on nymphs and adults has also been reported here for the first time.

  14. Dynamics of biotypes B and Q of the whitefly Bemisia tabaci and its impact on insecticide resistance.

    PubMed

    Horowitz, Abraham Rami; Ishaaya, Isaac

    2014-10-01

    The whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a key pest in many agricultural crops, including vegetables, ornamentals and field crops. B. tabaci is known for its genetic diversity, which is expressed in a complex of biotypes or, as recently suggested, a complex of distinct cryptic species. The biotypes are largely differentiated on the basis of biochemical or molecular polymorphism and differ in characteristics such as host plant range, attraction by natural enemies, secondary symbionts and expression of insecticide resistance. An extensive survey of B. tabaci biotypes and their impact on insecticide resistance was conducted from 2003 to 2012 in cotton fields and other crops from several locations in Israel. Two biotypes of B. tabaci, B and Q, were identified, and some differences in the biotype dynamics were recorded from different areas. In northern Israel from 2003 to 2007, a higher proportion of the B biotype was consistently found in early season. However, by the end of the season a definite rise of the Q biotype was sampled, ranging from 60 to 100%, along with high resistance to the insect growth regulator (IGR) pyriproxyfen and to a lesser extent to the neonicotinoid insecticides. In fields located in the central part of Israel, the Q biotype was predominant throughout the seasons, with high resistance to pyriproxyfen. Since 2009, a significant shift in the biotype ratios has been observed: the B biotype has come to predominate over the Q biotype ranging up to 90% or more in most fields. At the same time, resistance to the IGR pyriproxyfen was reduced considerably. The possible reasons for the change in the dynamics of B. tabaci biotypes, and its implications for resistance management, are discussed. Strong B. tabaci resistance to pyriproxyfen in Israel has been associated with the Q rather than with the B biotype. The B biotype is more competitive than the Q biotype under untreated conditions. Reduction in the acreage of cotton fields

  15. Transient receptor potential is essential for high temperature tolerance in invasive Bemisia tabaci Middle East Asia minor 1 cryptic species.

    PubMed

    Lü, Zhi-Chuang; Li, Qian; Liu, Wan-Xue; Wan, Fang-Hao

    2014-01-01

    Temperature is an important factor in affecting population dynamics and diffusion distribution of organisms. Alien species can successfully invade and colonize to various temperature environments, and one of important reasons is that alien species have a strong resistance to stress temperature. Recently, researchers have focused on the mechanisms of temperature sensing to determine the sensing and regulation mechanisms of temperature adaptation. The transient receptor potential (TRP) is one of the key components of an organism's temperature perception system. TRP plays important roles in perceiving temperature, such as avoiding high temperature, low temperature and choosing the optimum temperature. To assess high temperature sensation and the heat resistance role of the TRP gene, we used 3' and 5' rapid-amplification of cDNA ends to isolate the full-length cDNA sequence of the TRP gene from Bemisia tabaci (Gennadius) MEAM1 (Middle East Asia Minor 1), examined the mRNA expression profile under various temperature conditions, and identified the heat tolerance function. This is the first study to characterize the TRP gene of invasive B. tabaci MEAM1 (MEAM1 BtTRP). The full-length cDNA of MEAM1 BtTRP was 3871 bp, and the open reading frames of BtTRP was 3501 bp, encoding 1166 amino acids. Additionally, the BtTRP mRNA expression level was significantly increased at 35°C. Furthermore, compared with control treatments, the survival rate of B. tabaci MEAM1 adults was significantly decreased under high temperature stress conditions after feeding with dsRNA BtTRP. Collectively, these results showed that MEAM1 BtTRP is a key element in sensing high temperature and plays an essential role in B. tabaci MEAM1 heat tolerance ability. Our data improved our understanding of the mechanism of temperature sensation in B. tabaci MEAM1 at the molecular level and could contribute to the understanding of the thermal biology of B. tabaci MEAM1 within the context of global climate change.

  16. Salicylic acid is required for Mi-1-mediated resistance of tomato to whitefly Bemisia tabaci, but not for basal defense to this insect pest.

    PubMed

    Rodríguez-Álvarez, C I; López-Climent, M F; Gómez-Cadenas, A; Kaloshian, I; Nombela, G

    2015-10-01

    Plant defense to pests or pathogens involves global changes in gene expression mediated by multiple signaling pathways. A role for the salicylic acid (SA) signaling pathway in Mi-1-mediated resistance of tomato (Solanum lycopersicum) to aphids was previously identified and its implication in the resistance to root-knot nematodes is controversial, but the importance of SA in basal and Mi-1-mediated resistance of tomato to whitefly Bemisia tabaci had not been determined. SA levels were measured before and after B. tabaci infestation in susceptible and resistant Mi-1-containing tomatoes, and in plants with the NahG bacterial transgene. Tomato plants of the same genotypes were also screened with B. tabaci (MEAM1 and MED species, before known as B and Q biotypes, respectively). The SA content in all tomato genotypes transiently increased after infestation with B. tabaci albeit at variable levels. Whitefly fecundity or infestation rates on susceptible Moneymaker were not significantly affected by the expression of NahG gene, but the Mi-1-mediated resistance to B. tabaci was lost in VFN NahG plants. Results indicated that whiteflies induce both SA and jasmonic acid accumulation in tomato. However, SA has no role in basal defense of tomato against B. tabaci. In contrast, SA is an important component of the Mi-1-mediated resistance to B. tabaci in tomato.

  17. Sensitivity of Bemisia tabaci (Hemiptera: Aleyrodidae) to several new insecticides in China: effects of insecticide type and whitefly species, strain, and stage.

    PubMed

    Xie, Wen; Liu, Yang; Wang, Shaoli; Wu, Qingjun; Pan, Huipeng; Yang, Xin; Guo, Litao; Zhang, Youjun

    2014-01-01

    Whitefly biotypes B and Q are the two most damaging members of the Bemisia tabaci (Hemiptera: Aleyrodidae) species complex. Control of B. tabaci (and especially of Q) has been impaired by resistance to commonly used insecticides. To find new insecticides for B. tabaci management in China, we investigated the sensitivity of eggs, larvae, and adults of laboratory strains of B and Q (named Lab-B and Lab-Q) and field strains of Q to several insecticides. For eggs, larvae, and adults of B. tabaci and for six insecticides (cyantraniliprole, chlorantraniliprole, pyriproxyfen, buprofezin, acetamiprid, and thiamethoxam), LC50 values were higher for Lab-Q than for Lab-B; avermectin LC50 values, however, were low for adults of both Lab-Q and Lab-B. Based on the laboratory results, insecticides were selected to test against eggs, larvae, and adults of four field strains of B. tabaci Q. Although the field strains differed in their sensitivity to the insecticides, the eggs and larvae of all strains were highly sensitive to cyantraniliprole, and the adults of all strains were highly sensitive to avermectin. The eggs, larvae, and adults of B. tabaci Q were generally more resistant than those of B. tabaci B to the tested insecticides. B. tabaci Q eggs and larvae were sensitive to cyantraniliprole and pyriproxyfen, whereas B. tabaci Q adults were sensitive to avermectin. Field trials should be conducted with cyantraniliprole, pyriproxyfen, and avermectin for control of B. tabaci Q and B in China. © The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.

  18. Aqueous Extracts of Some Medicinal Plants are as Toxic as Lmidacloprid to the Sweet Potato Whitefly, Bemisia tabaci

    PubMed Central

    Ateyyat, Mazen A.; Al-Mazra'awi, Mohammad; Abu-Rjai, Talal; Shatnawi, Mohamad A.

    2009-01-01

    Aqueous extracts of nine plants, known to have medicinal activity, were tested for their toxicity against the sweet potato whitefly, Bemisia tabaci Genn. (Homoptera: Aleurodidae) compared to the toxicity of the insecticide, Imidacloprid. Extracts of Lepidiuim sativum L. (Brassicales: Brassicaceae) killed 71 % of early stage nymphs, which was not significantly different from mortality caused by Imidacloprid. Treatment of pupae with three plant extracts, L. sativum, Achillea biebersteinii L. (Asterales: Asteraceae), or Retama raetam (Forssk.) Webb and Berthel (Fabales: Fabaceae) prevented adult development, and treatment with R. raetam extract killed adults, at levels that were not significantly different from Imidacloprid. None of the other plants showed significant toxicity. However extracts of four plants, Pimpinella anisum L. (Apiales: Apiaceae), Galium longifolium (Sibth. and SM.) (Gentianales: Rubiaceae), R. raetam and Ballota undulata Bentham (Lamiales: Lamiaceae) had a repellent effect. PMID:19613450

  19. Are yellow sticky traps an effective method for control of sweetpotato whitefly, Bemisia tabaci, in the greenhouse or field?

    PubMed

    Lu, Yaobin; Bei, Yawei; Zhang, Jinming

    2012-01-01

    Yellow sticky traps are a common method for monitoring many pests, but it has not been shown whether they could be used as a control method. In this study the impact of yellow sticky traps on the population dynamics of the sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) was determined in the greenhouse and field. In the greenhouse, yellow sticky traps significantly suppressed the population increase of adult and immature whiteflies. The whitefly densities in the greenhouse with traps were significantly lower than the greenhouse without traps. In the field, traps did not have a significant impact on the population dynamics of adult and immature whiteflies. The densities in fields with traps were very similar to fields without traps. These results suggest that yellow sticky traps can be used as an effective method for the control of whiteflies in the greenhouse, but not in the field. This information will prove useful for the effective management of whiteflies in greenhouses.

  20. Are Yellow Sticky Traps an Effective Method for Control of Sweetpotato Whitefly, Bemisia tabaci, in the Greenhouse or Field?

    PubMed Central

    Lu, Yaobin; Bei, Yawei; Zhang, Jinming

    2012-01-01

    Yellow sticky traps are a common method for monitoring many pests, but it has not been shown whether they could be used as a control method. In this study the impact of yellow sticky traps on the population dynamics of the sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) was determined in the greenhouse and field. In the greenhouse, yellow sticky traps significantly suppressed the population increase of adult and immature whiteflies. The whitefly densities in the greenhouse with traps were significantly lower than the greenhouse without traps. In the field, traps did not have a significant impact on the population dynamics of adult and immature whiteflies. The densities in fields with traps were very similar to fields without traps. These results suggest that yellow sticky traps can be used as an effective method for the control of whiteflies in the greenhouse, but not in the field. This information will prove useful for the effective management of whiteflies in greenhouses. PMID:23445077

  1. A Primary Screening and Applying of Plant Volatiles as Repellents to Control Whitefly Bemisia tabaci (Gennadius) on Tomato

    PubMed Central

    Du, Wenxiao; Han, Xiaoqing; Wang, Yubo; Qin, Yuchuan

    2016-01-01

    With the goal of finding a new way to reduce population densities of Bemisia tabaci biotype Q in greenhouses, seven repellent volatile chemicals and their combinations were screened. The mixture of DLCO (D-limonene, citral and olive oil (63:7:30)) had a better cost performance(SC50 = 22.59 mg/ml)to repel whiteflies from settling than the other mixtures or single chemicals. In the greenhouse, in both the choice test and the no-choice tests, the number of adult whiteflies that settled on 1% DLCO-treated tomato plants was significantly lower than those settling on the control plants for the different exposure periods (P < 0.01). In the choice test, the egg amount on the treated tomato plants was significantly lower (P < 0.01) than that on the control plants, but there was no significant difference (P > 0.05) between the number of eggs on treated and control plants in the no-choice test. Compared with the controls, 1% DLCO did not cause significantly statistic mortality rates (P > 0.05) out of different living stages of B. tabaci. The tests for evaluating the repellent efficacy, showed that a slow-releasing bottle containing the mixture had a period of efficacy of 29 days, and the application of this mixture plus a yellow board used as a push-pull strategy in the greenhouse was also effective. PMID:26907368

  2. Flupyradifurone effectively manages whitefly Bemisia tabaci MED (Hemiptera: Aleyrodidae) and tomato yellow leaf curl virus in tomato.

    PubMed

    Roditakis, Emmanouil; Stavrakaki, Marianna; Grispou, Maria; Achimastou, Aikaterini; Van Waetermeulen, Xavier; Nauen, Ralf; Tsagkarakou, Anastasia

    2017-08-01

    The cotton whitefly Bemisia tabaci (Gennadius) is among the most important pests of numerous crops and a vector of more than 100 plant viruses, causing significant crop losses worldwide. Managing this pest as well as inhibiting the transmission of major viruses such as tomato yellow leaf curl virus (TYLCV) are of utmost importance for sustainable yields. The efficacy against both whitefly and virus transmission of the novel systemic butenolide insecticide flupyradifurone was investigated in this study. The inhibition of TYLCV transmission by flupyradifurone was compared to that by thiamethoxam, a neonicotinoid insecticide reported to inhibit virus transmission. The experiment was performed under high virus pressure conditions (10 viruliferous insects per plant for 48 h) using a fully characterized field strain of B. tabaci. The insecticides were foliarly applied at recommended label rates under greenhouse conditions. Flupyradifurone suppressed virus transmission by 85% while levels of suppression after thiamethoxam treatments were just 25% and significantly lower. In untreated control plots, 100% of plants were infected by TYLCV. The observed difference in the potential to suppress virus transmission is linked to a strong knockdown effect as well as prolonged feeding inhibition in flupyradifurone treatments. Flupyradifurone is shown to be an extremely useful, fast-acting, new chemical tool in integrated crop management offering simultaneous control of whiteflies and strong suppression of viral infections via its rapid knockdown action and good residual activity. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  3. Reproduction of the whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) B biotype in maize fields (Zea mays L.) in Brazil.

    PubMed

    Quintela, Eliane D; Abreu, Aluana G; Lima, Julyana F Dos S; Mascarin, Gabriel M; Santos, Jardel B Dos; Brown, Judith K

    2016-11-01

    Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae) was observed to have completed its reproductive cycle from the egg to the adult on maize (Zea mays L.). Field and screenhouse studies were carried out to investigate the durability of this putative and unprecedented adaptation to a grass host. Analysis of the mitochondrial COI gene sequence identified the maize-associated B. tabaci as the exotic B biotype (major clade North Africa-Mediterranean-Middle East). Results showed that whiteflies migrated from soybean crops and successfully established in maize plants. Females exhibited a preference for oviposition primarily on the first and second leaves of maize, but were also able to colonise developing leaves. A high, natural infestation on maize (193.3 individuals, all developmental stages) was observed within a 7.1 cm(2) designated 'observation area'. Whiteflies collected from naturally infested maize leaves and allowed to oviposit on maize seedlings grown in a screenhouse developed from egg to adulthood in 28.6 ± 0.2 days. This is the first report of the B biotype completing its development on maize plants. This surprising anomaly indicates that the B biotype is capable of adapting to monocotyledonous host plants, and importantly, broadens the host range to include at least one species in the Poaceae. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  4. Toxicity of sucrose octanoate to egg, nymphal, and adult Bemisia tabaci (Hemiptera: Aleyrodidae) using a novel plant-based bioassay.

    PubMed

    McKenzie, C L; Weathersbee, A A; Puterka, Gary J

    2005-08-01

    The sweetpotato whitefly, Bemisia tabaci (Gennadius), B biotype, presents a unique problem for vegetable growers by serving as a vector of plant viruses and by inducing physiological disorders of leaves and fruit. An action threshold of a single whitefly is necessary because of the threat of disease in many areas and growers rely heavily on a single class of insecticides (neonicotinoids) for whitefly control. Additional control methods are needed to manage this pest in commercial vegetables. Extracts of wild tobacco contain natural sugar esters that have previously been shown effective in controlling many soft-bodied insects. We developed a novel tomato leaf bioassay system to assess a synthetic sugar ester derivative, sucrose octanoate, for insecticidal activity against the eggs, nymphs, and adults of B. tabaci. The LC50 values for sucrose octanoate against adults, second instars, and fourth instars of the whitefly were 880, 686, and 1,571 ppm, respectively. The LC50 against whitefly eggs was higher (11,446 ppm) but indicated that some egg mortality occurred at the recommended application rate of 0.8-1.2% (3,200-4,800 ppm [Al]). Toxicity of sugar esters to whitefly eggs has not been reported previously. The tomato leaf bioassay produced reliable and repeatable results for whitefly toxicity studies and predicted that effective nymph and adult whitefly control can be achieved with sucrose octanoate at application rates < or = 1% (4,000 ppm [AI]). Field efficacy studies are warranted to determine whether this biorational pesticide has application in commercial tomato production.

  5. Population genetics of invasive Bemisia tabaci (Hemiptera: Aleyrodidae) cryptic species in the United States based on microsatellite markers.

    PubMed

    Dickey, Aaron M; Osborne, Lance S; Shatters, Robert G; Hall, Paula A M; Mckenzie, Cindy L

    2013-06-01

    The Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) cryptic species complex of whiteflies contains two species, MEAM1 and MED, that are highly invasive in supportive climates the world over. In the United States, MEAM1 occurs both in the field and in the greenhouse, but MED is only found in the greenhouse. To make inferences about the population structure of both species, and the origin and recent spread of MED within the United States, 987 MEAM1 whiteflies and 340 MED whiteflies were genotyped at six and seven microsatellite loci, respectively, for population genetic analyses. Major results of the study are 1) MED exhibits more population structure and genetic differentiation than MEAM1, 2) nuclear microsatellite markers exhibit a high degree of concordance with mitochondrial markers recovering a major east-west phylogeographic break within MED, 3) both eastern and western MED are found throughout the continental United States and eastern MED is present in Hawaii, and 4) MEAM1 contains two greenhouse U.S. populations significantly differentiated from other U.S. MEAM1. The results suggest that MED was introduced into the United States on at least three occasions and rapidly spread throughout the United States, showing no discernible differentiation across 7,000 km. The results further suggest that there is an enhanced role of the protected agricultural environment in promoting genetic differentiation in both invasive B. tabaci cryptic species.

  6. Antifeedant activity of botanical crude extracts and their fractions on Bemisia tabaci (Homoptera: Aleyrodidae) adults: II. Sechium pittieri (Cucurbitaceae).

    PubMed

    Flores, Guillermo; Hilje, Luko; Mora, Gerardo A; Carballo, Manuel

    2008-12-01

    Bemisia tabaci is a key pest of vegetables and other crops worldwide, but it is a particularly serious problem in the tropics, due to its ability to transmit several types of viruses, especially begomoviruses (Geminiviridae). Therefore, a preventive approach to deal with viral epidemics may be the deployment of repellents or phagodeterrents at earlier stages of plant development (critical period). Thus, the crude extract and four fractions thereof (water, water: methanol, methanol, and diethyl ether) of wild "tacaco" (Sechium pittieri, Cucurbitaceae), were tested for phagodeterrence to B. tabaci adults under greenhouse conditions, on tomato plants, in Costa Rica. Both restricted-choice and unrestricted-choice experiments showed that the crude extract as well as some fractions exert such effect on the insect. In the former (in sleeve cages), fractions caused deterrence at doses as low as 0.1% (ether) and 0.5% (water and water: methanol), with the methanol fraction showing no activity. However, in the latter (plants exposed in a greenhouse) no one of the fractions performed well, suggesting that the deterrent principles somehow decomposed under the experimental conditions.

  7. Biotype status and genetic polymorphism of the whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) in Greece: mitochondrial DNA and microsatellites.

    PubMed

    Tsagkarakou, A; Tsigenopoulos, C S; Gorman, K; Lagnel, J; Bedford, I D

    2007-02-01

    The genetic polymorphism and the biotype identity of the tobacco whitefly Bemisia tabaci (Gennadius) have been studied in population samples taken from different localities within Greece from cultivated plants growing in greenhouses or in open environments and from non-cultivated plants. Two different approaches were used: sequencing of the mitochondrial cytochrome oxidase I (mtCOI) gene and genotyping using microsatellite markers. Analyses of the mtCOI sequences revealed a high homogeneity between the Greek samples which clustered together with Q biotype samples that had been collected from other countries. When genetic polymorphism was examined using six microsatellite markers, the Greek samples, which were all characterized as Q biotype were significantly differentiated from each other and clustered into at least two distinct genetic populations. Moreover, based on the fixed differences revealed by the mtCOI comparison of known B. tabaci biotype sequences, two diagnostic tests for discriminating between Q and B and non-Q/non-B biotypes were developed. Implementation of these diagnostic tools allowed an absence of the B biotype and presence of the Q biotype in the Greek samples to be determined.

  8. A Primary Screening and Applying of Plant Volatiles as Repellents to Control Whitefly Bemisia tabaci (Gennadius) on Tomato

    NASA Astrophysics Data System (ADS)

    Du, Wenxiao; Han, Xiaoqing; Wang, Yubo; Qin, Yuchuan

    2016-02-01

    With the goal of finding a new way to reduce population densities of Bemisia tabaci biotype Q in greenhouses, seven repellent volatile chemicals and their combinations were screened. The mixture of DLCO (D-limonene, citral and olive oil (63:7:30)) had a better cost performance(SC50 = 22.59 mg/ml)to repel whiteflies from settling than the other mixtures or single chemicals. In the greenhouse, in both the choice test and the no-choice tests, the number of adult whiteflies that settled on 1% DLCO-treated tomato plants was significantly lower than those settling on the control plants for the different exposure periods (P < 0.01). In the choice test, the egg amount on the treated tomato plants was significantly lower (P < 0.01) than that on the control plants, but there was no significant difference (P > 0.05) between the number of eggs on treated and control plants in the no-choice test. Compared with the controls, 1% DLCO did not cause significantly statistic mortality rates (P > 0.05) out of different living stages of B. tabaci. The tests for evaluating the repellent efficacy, showed that a slow-releasing bottle containing the mixture had a period of efficacy of 29 days, and the application of this mixture plus a yellow board used as a push-pull strategy in the greenhouse was also effective.

  9. Effects of Isaria fumosorosea on TYLCV (Tomato Yellow Leaf Curl Virus) Accumulation and Transmitting Capacity of Bemisia tabaci

    PubMed Central

    2016-01-01

    Tomato yellow leaf curl virus (TYLCV) is transmitted by the Bemisia tabaci pest Middle East-Asia Minor 1 (MEAM1) in China. Isaria fumosorosea is a fungal pathogen of B. tabaci. However, the effects of fungal infection on TYLCV expression and transmission by MEAM1 are unclear. In this study, potted tomatoes containing second instar nymphs of MEAM1 were treated with I. fumosorosea IfB01 strain and the relationship between fungal infection in MEAM1 and its TYLCV transmission capacity was investigated. The results indicated that a significantly (p < 0.05) decreased incidence of transmission of TYLCV-infected plants (ITYPs) transmitted by second instar nymphs of MEAM1 infected with fungus. Further, we found a negative correlation between fungal conidial concentrations and eclosion rates of MEAM1, and a positive correlation between ITYPs and eclosion. In addition, when each plant was exposed to three adults treated with fungus, a significantly decreased transmission of TYLCV (TYTE) was observed in the infected group. However, the incidence of TYLCV-carrying MEAM1 adults (ITYAs) was not significantly different in the infected and control groups (p < 0.05). Nevertheless, a significant decrease in viral accumulation using TYLCV AC2 gene as a marker was observed in the fungus-infected MEAM1. In conclusion, the results suggested that I. fumosorosea infection decreases TYLCV accumulation in MEAM1 and subsequently reduces its transmission. Our study provides new insights into the relationship between host plant, plant virus, insect vector, and entomopathogenic fungus. PMID:27716852

  10. Heritability and Evolutionary Potential in Thermal Tolerance Traits in the Invasive Mediterranean Cryptic Species of Bemisia tabaci (Hemiptera: Aleyrodidae)

    PubMed Central

    Wang, Ren; Wan, Fang-Hao

    2014-01-01

    With advancing global climate change, the analysis of thermal tolerance and evolutionary potential is important in explaining the ecological adaptation and changes in the distribution of invasive species. To reveal the variation of heat resistance and evolutionary potential in the invasive Mediterranean cryptic species of Bemisia tabaci, we selected two Chinese populations—one from Harbin, N China, and one from Turpan, S China—that experience substantial heat and cold stress and conducted knockdown tests under static high- and low-temperature conditions. ANOVAs indicated significant effects of populations and sex on heat knockdown time and chill coma recovery time. The narrow-sense heritability (h2) estimates of heat tolerance based on a parental half-sibling breeding design ranged from 0.47±0.03 to 0.51±0.06, and the estimates of cold tolerance varied from 0.33±0.07 to 0.36±0.06. Additive genetic variances were significantly different from zero for both heat and cold tolerance. These results suggest that invasive B. tabaci Mediterranean cryptic species possesses a strong ability to respond to thermal selection and develops rapid resistance to climate change. PMID:25054554

  11. Status of Resistance of Bemisia tabaci (Hemiptera: Aleyrodidae) to Neonicotinoids in Iran and Detoxification by Cytochrome P450-Dependent Monooxygenases.

    PubMed

    Basij, M; Talebi, K; Ghadamyari, M; Hosseininaveh, V; Salami, S A

    2017-02-01

    Nine Bemisia tabaci (Gennadius) populations were collected from different regions of Iran. In all nine populations, only one biotype (B biotype) was detected. Susceptibilities of these populations to imidacloprid and acetamiprid were assayed. The lethal concentration 50 values (LC50) for different populations showed a significant discrepancy in the susceptibility of B. tabaci to imidacloprid (3.76 to 772.06 mg l(-1)) and acetamiprid (4.96 to 865 mg l(-1)). The resistance ratio of the populations ranged from 9.72 to 205.20 for imidacloprid and 6.38 to 174.57 for acetamiprid. The synergistic effects of piperonylbutoxide (PBO) and S,S,S-tributylphosphorotrithioate (DEF) were evaluated for the susceptible (RF) and resistant (JR) populations for the determination of the involvement of cytochrome P450-dependent monooxygenase and carboxylesterase, respectively, in their resistance mechanisms. The results showed that PBO overcame the resistance of the JR population to both imidacloprid and acetamiprid, with synergistic ratios of 72.7 and 106.9, respectively. Carboxylesterase, glutathione S-transferase and cytochrome P450-dependent monooxygenase were studied biochemically, for the purpose of measuring the activity of the metabolizing enzymes in order to determine which enzymes are directly involved in neonicotinoid resistance. There was an increase in the activity of cytochrome P450-dependent monooxygenase up to 17-fold in the resistant JR population (RR = 205.20). The most plausible activity of cytochrome P450-dependent monooxygenase correlated with the resistances of imidacloprid and acetamiprid, and this suggests that cytochrome P450-dependent monooxygenase is the only enzyme system responsible for neonicotinoid resistance in the nine populations of B. tabaci.

  12. Rapid cold hardening and expression of heat shock protein genes in the B-biotype Bemisia tabaci.

    PubMed

    Wang, Haihong; Lei, Zhongren; Li, Xue; Oetting, Ronald D

    2011-02-01

    This paper describes the rapid cold hardening processes of the sweetpotato whitefly, Bemisia tabaci (Gennadius). It was found that all developmental stages of B. tabaci have the capacity of rapid cold hardening and the length of time required to induce maximal cold hardiness at 0 °C varies with stage. There was only 18.3% survival when adult whiteflies were transferred directly from 26 °C to -8.5 °C for 2 h. However, exposure to 0 °C for 1 h before transfer to -8.5 °C increased the survival to 81.2%. The whiteflies show "prefreeze" mortality when they were exposed to temperatures above the supercooling point (SCP), although the range of SCP of whiteflies is -26 °C to -29 °C. The rapid cold hardening had no effect on SCP and reduced the lower lethal temperature of adults from -9 °C to -11 °C. Rapid cold-hardened adults had a similar lifespan as the control group but deposited fewer eggs than nonhardened individuals. The expression profiles during cold hardening and recovery from this process revealed that HSP90 did not respond to cold stress. However, HSP70 and HSP20 were significantly induced by cold with different temporal expression patterns. These results suggest that the rapid cold hardening response is possibly advantageous to whiteflies that are often exposed to drastic temperature fluctuations in spring or autumn in northern China, and the expression of HSP70 and HSP20 may be associated with the cold tolerance of B. tabaci.

  13. Normal adult survival but reduced Bemisia tabaci oviposition rate on tomato lines carrying an introgression from S. habrochaites.

    PubMed

    Lucatti, Alejandro F; Meijer-Dekens, Fien R G; Mumm, Roland; Visser, Richard G F; Vosman, Ben; van Heusden, Sjaak

    2014-12-24

    Host plant resistance has been proposed as one of the most promising approaches in whitefly management. Already in 1995 two quantitative trait loci (Tv-1 and Tv-2) originating from S. habrochaites CGN1.1561 were identified that reduced the oviposition rate of the greenhouse whitefly (Trialeurodes vaporariorum). After this first study, several others identified QTLs affecting whitefly biology as well. Generally, the QTLs affecting oviposition were highly correlated with a reduction in whitefly survival and the presence of high densities of glandular trichomes type IV. The aim of our study was to further characterize Tv-1 and Tv-2, and to determine their role in resistance against Bemisia tabaci. We selected F2 plants homozygous for the Tv-1 and Tv-2 QTL regions and did three successive backcrosses without phenotypic selection. Twenty-three F2BC3 plants were phenotyped for whitefly resistance and differences were found in oviposition rate of B. tabaci. The F2BC3 plants with the lowest oviposition rate had an introgression on Chromosome 5 in common. Further F2BC4, F2BC4S1 and F2BC4S2 families were developed, genotyped and phenotyped for adult survival, oviposition rate and trichome type and density. It was possible to confirm that an introgression on top of Chr. 5 (OR-5), between the markers rs-2009 and rs-7551, was responsible for reducing whitefly oviposition rate. We found a region of 3.06 Mbp at the top of Chr. 5 (OR-5) associated with a reduction in the oviposition rate of B. tabaci. This reduction was independent of the presence of the QTLs Tv-1 and Tv-2 as well as of the presence of trichomes type IV. The OR-5 locus will provide new opportunities for resistance breeding against whiteflies, which is especially relevant in greenhouse cultivation.

  14. Tri-Tek (Petroleum Horticultural Oil) and Beauveria bassiana: Use in Eradication Strategies for Bemisia tabaci Mediterranean Species in UK Glasshouses

    PubMed Central

    Cuthbertson, Andrew G. S.; Collins, Debbie A.

    2015-01-01

    The sweetpotato whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a pest of global importance on both outdoor and glasshouse crops. To date, B. tabaci has not become established in the UK. The UK holds Protected Zone status against this pest and, as a result, B. tabaci entering on plant material is subjected to a policy of eradication. Mediterranean species is now the most prevalent Bemisia species entering the UK. Increasing neonicotinoid resistance is becoming increasingly widespread and problematic with this species. As a result, this continues to pose problems for eradication strategies. The current study investigates the efficacy of Tri-Tek (a petroleum horticultural oil awaiting UK registration) and the fungus Beauveria bassiana to act as control agents against Mediterranean species in UK glasshouses. Tri-Tek provided 100% egg mortality compared to 74% for B. bassiana. When tested against second instar larvae, mortalities of 69% and 65% respectively were achieved. Both products can be successfully “tank-mixed”. A tank-mix application provided 95.5% mortality of second instar larvae under glasshouse conditions. The potential integration of both products into current Bemisia eradication strategies in UK glasshouses is discussed. PMID:26463071

  15. Tri-Tek (Petroleum Horticultural Oil) and Beauveria bassiana: Use in Eradication Strategies for Bemisia tabaci Mediterranean Species in UK Glasshouses.

    PubMed

    Cuthbertson, Andrew G S; Collins, Debbie A

    2015-02-12

    The sweetpotato whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a pest of global importance on both outdoor and glasshouse crops. To date, B. tabaci has not become established in the UK. The UK holds Protected Zone status against this pest and, as a result, B. tabaci entering on plant material is subjected to a policy of eradication. Mediterranean species is now the most prevalent Bemisia species entering the UK. Increasing neonicotinoid resistance is becoming increasingly widespread and problematic with this species. As a result, this continues to pose problems for eradication strategies. The current study investigates the efficacy of Tri-Tek (a petroleum horticultural oil awaiting UK registration) and the fungus Beauveria bassiana to act as control agents against Mediterranean species in UK glasshouses. Tri-Tek provided 100% egg mortality compared to 74% for B. bassiana. When tested against second instar larvae, mortalities of 69% and 65% respectively were achieved. Both products can be successfully "tank-mixed". A tank-mix application provided 95.5% mortality of second instar larvae under glasshouse conditions. The potential integration of both products into current Bemisia eradication strategies in UK glasshouses is discussed.

  16. How to Start with a Clean Crop: Biopesticide Dips Reduce Populations of Bemisia tabaci (Hemiptera: Aleyrodidae) on Greenhouse Poinsettia Propagative Cuttings.

    PubMed

    Buitenhuis, Rosemarije; Brownbridge, Michael; Brommit, Angela; Saito, Taro; Murphy, Graeme

    2016-09-26

    (1) Global movement of propagative plant material is a major pathway for introduction of Bemisia tabaci (Hemiptera: Aleyrodidae) into poinsettia greenhouses. Starting a poinsettia crop with high pest numbers disrupts otherwise successful biological control programs and widespread resistance of B. tabaci against pesticides is limiting growers' options to control this pest; (2) This study investigated the use of several biopesticides (mineral oil, insecticidal soap, Beauveria bassiana, Isaria fumosorosea, Steinernema feltiae) and combinations of these products as immersion treatments (cutting dips) to control B. tabaci on poinsettia cuttings. In addition, phytotoxicity risks of these treatments on poinsettia cuttings, and effects of treatment residues on mortality of commercial whitefly parasitoids (Eretmocerus eremicus and Encarsia formosa) were determined; (3) Mineral oil (0.1% v/v) and insecticidal soap (0.5%) + B. bassiana (1.25 g/L) were the most effective treatments; only 31% and 29%, respectively, of the treated B. tabaci survived on infested poinsettia cuttings and B. tabaci populations were lowest in these treatments after eight weeks. Phytotoxicity risks of these treatments were acceptable, and dip residues had little effect on survival of either parasitoid, and are considered highly compatible; (4) Use of poinsettia cutting dips will allow growers to knock-down B. tabaci populations to a point where they can be managed successfully thereafter with existing biocontrol strategies.

  17. Rapid spread of a recently introduced virus (tomato yellow leaf curl virus) and its vector Bemisia tabaci (Hemiptera: Aleyrodidae) in Liaoning Province, China.

    PubMed

    Zhang, Wan-Min; Fu, Hai-Bin; Wang, Wen-Hang; Piao, Chun-Shu; Tao, Yun-Li; Guo, Dong; Chu, Dong

    2014-02-01

    In Liaoning Province, China, tomato yellow leaf curl virus (TYLCV) was first detected in 2009 and in only four counties. To quantify the spread of TYLCV and to identify potential factors influencing its spread in Liaoning Province, we assayed for TYLCV within 1,055 whiteflies (Bemisia tabaci (Gennadius) complex) from 74 populations and 29 counties in 2011. The B. tabaci species of these individuals was determined based on molecular markers. TYLCV was found in 13 counties (Donggang, Liaoyang, Kazuo, Lingyuan, Heishan, Liaozhong, Kaiyuan, Taian, Dawa, Dashiqiao, Beizhen, Linghai, and Xingcheng) and was most frequently detected in the central plain. In addition, the percentage of whiteflies with TYLCV was significantly higher in B. tabaci Q than in B. tabaci B but was unrelated to the hosts (pepper, eggplant, tomato, cucumber, and kidney bean) on which the whiteflies had been collected. These results demonstrate that TYLCV has spread rapidly in Liaoning Province since its first detection and suggest that its spread is more closely associated with the introduction of B. tabaci Q than with the species of host plant. These findings also indicate that controls are now needed to reduce the further spread of TYLCV and that these controls should include the management of B. tabaci Q populations.

  18. How to Start with a Clean Crop: Biopesticide Dips Reduce Populations of Bemisia tabaci (Hemiptera: Aleyrodidae) on Greenhouse Poinsettia Propagative Cuttings

    PubMed Central

    Buitenhuis, Rosemarije; Brownbridge, Michael; Brommit, Angela; Saito, Taro; Murphy, Graeme

    2016-01-01

    (1) Global movement of propagative plant material is a major pathway for introduction of Bemisia tabaci (Hemiptera: Aleyrodidae) into poinsettia greenhouses. Starting a poinsettia crop with high pest numbers disrupts otherwise successful biological control programs and widespread resistance of B. tabaci against pesticides is limiting growers’ options to control this pest; (2) This study investigated the use of several biopesticides (mineral oil, insecticidal soap, Beauveria bassiana, Isaria fumosorosea, Steinernema feltiae) and combinations of these products as immersion treatments (cutting dips) to control B. tabaci on poinsettia cuttings. In addition, phytotoxicity risks of these treatments on poinsettia cuttings, and effects of treatment residues on mortality of commercial whitefly parasitoids (Eretmocerus eremicus and Encarsia formosa) were determined; (3) Mineral oil (0.1% v/v) and insecticidal soap (0.5%) + B. bassiana (1.25 g/L) were the most effective treatments; only 31% and 29%, respectively, of the treated B. tabaci survived on infested poinsettia cuttings and B. tabaci populations were lowest in these treatments after eight weeks. Phytotoxicity risks of these treatments were acceptable, and dip residues had little effect on survival of either parasitoid, and are considered highly compatible; (4) Use of poinsettia cutting dips will allow growers to knock-down B. tabaci populations to a point where they can be managed successfully thereafter with existing biocontrol strategies. PMID:27681741

  19. Age-specific interaction between the parasitoid, Encarsia formosa and its host, the silverleaf whitefly, Bemisia tabaci (Strain B)

    PubMed Central

    Hu, Jing S.; Gelman, Dale B.; Blackburn, Michael B.

    2003-01-01

    The effect of hostage, the instar of Bemisia tabaci (Gennadius) parasitized, on the growth and development of Encarsia formosa (Gahan) was studied. E. formosa was able to parasitize and complete its life cycle no matter which instar of B. tabaci (Strain B), [also identified as B. argentifolii (Bellows and Perring)], was provided for oviposition, but parasitoid development was significantly slower when 1st or 2nd instar B. tabaci rather than 3rd or 4th instars were parasitized. Host age influenced the day on which E. formosa nymphs hatching from eggs was first observed. Mean embryonic development was significantly longer when 1st (5.4 days) rather than 2nd, 3rd or 4th instars (4.1, 3.4 and 3.5 days, respectively) were parasitized. The duration of the 1st instar parasitoid and the pupa, but not the 2nd or 3rd instar parasitoid, were also significantly greater when 1st instars were parasitized than when older host instars were parasitized. Interestingly, no matter which instar was parasitized, the parasitoid did not molt to the 3rd instar until the 4th instar host had reached a depth of about 0.23 mm (Stage 4–5) and had initiated the nymphal-adult molt and adult development. Histological studies revealed that whitefly eye and wing structures had either disintegrated or were adult in nature whenever a 3rd instar parasitoid was present. It appears, then, that the molt of the parasitoid to its last instar is associated with the host whitefly's nymphal-adult molt. However, the initiation of the host's final molt, while a prerequisite for the parasitoid's 2nd–3rd instar molt, did not necessarily trigger this molt. In contrast to its significant effect on various aspects of parasitoid development, host instar did not significantly influence the mean size of the parasitoid larva, pupa, or adult. Larval and pupal length and adult head width were similar for all parasitoids, regardless of which host instar was parasitized as was adult longevity. Adult parasitoid emergence

  20. Is agriculture driving the diversification of the Bemisia tabaci species complex (Hemiptera: Sternorrhyncha: Aleyrodidae)?: Dating, diversification and biogeographic evidence revealed.

    PubMed

    Boykin, Laura M; Bell, Charles D; Evans, Gregory; Small, Ian; De Barro, Paul J

    2013-10-18

    Humans and insect herbivores are competing for the same food crops and have been for thousands of years. Despite considerable advances in crop pest management, losses due to insects remain considerable. The global homogenisation of agriculture has supported the range expansion of numerous insect pests and has been driven in part by human-assisted dispersal supported through rapid global trade and low-cost air passenger transport. One of these pests, is the whitefly, Bemisia tabaci, a cryptic species complex that contains some of the world's most damaging pests of agriculture. The complex shows considerable genetic diversity and strong phylogeographic relationships. One consequence of the considerable impact that members of the B. tabaci complex have on agriculture, is the view that human activity, particularly in relation to agricultural practices, such as use of insecticides, has driven the diversification found within the species complex. This has been particularly so in the case of two members of the complex, Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED), which have become globally distributed invasive species. An alternative hypothesis is that diversification is due to paleogeographic and paleoclimatological changes. The idea that human activity is driving speciation within the B. tabaci complex has never been tested, but the increased interest in fossil whiteflies and the growth in molecular data have enabled us to apply a relaxed molecular clock and so estimate divergence dates for the major lineages within the B. tabaci species complex. The divergence estimates do not support the view that human activity has been a major driver of diversification. Our analysis suggests that the major lineages within the complex arose approximately 60-30 mya and the highly invasive MED and MEAM1 split from the rest of the species complex around 12 mya well before the evolution of Homo sapiens and agriculture. Furthermore, the divergence dates coincide with a period

  1. Is agriculture driving the diversification of the Bemisia tabaci species complex (Hemiptera: Sternorrhyncha: Aleyrodidae)?: Dating, diversification and biogeographic evidence revealed

    PubMed Central

    2013-01-01

    Background Humans and insect herbivores are competing for the same food crops and have been for thousands of years. Despite considerable advances in crop pest management, losses due to insects remain considerable. The global homogenisation of agriculture has supported the range expansion of numerous insect pests and has been driven in part by human-assisted dispersal supported through rapid global trade and low-cost air passenger transport. One of these pests, is the whitefly, Bemisia tabaci, a cryptic species complex that contains some of the world’s most damaging pests of agriculture. The complex shows considerable genetic diversity and strong phylogeographic relationships. One consequence of the considerable impact that members of the B. tabaci complex have on agriculture, is the view that human activity, particularly in relation to agricultural practices, such as use of insecticides, has driven the diversification found within the species complex. This has been particularly so in the case of two members of the complex, Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED), which have become globally distributed invasive species. An alternative hypothesis is that diversification is due to paleogeographic and paleoclimatological changes. Results The idea that human activity is driving speciation within the B. tabaci complex has never been tested, but the increased interest in fossil whiteflies and the growth in molecular data have enabled us to apply a relaxed molecular clock and so estimate divergence dates for the major lineages within the B. tabaci species complex. The divergence estimates do not support the view that human activity has been a major driver of diversification. Conclusions Our analysis suggests that the major lineages within the complex arose approximately 60–30 mya and the highly invasive MED and MEAM1 split from the rest of the species complex around 12 mya well before the evolution of Homo sapiens and agriculture. Furthermore, the

  2. Transmission efficiency of tomato apex necrosis virus by Bemisia tabaci (Hemiptera: Aleyrodidae) biotype B in tomato.

    PubMed

    Barajas-Ortiz, M; León-Sicairos, C R; López-Valenzuela, J A; Reyes-Moreno, C; Valdez-Ortiz, A; Velarde-Félix, S; Peraza-Garay, F; Garzón-Tiznado, J A

    2013-08-01

    Tomato apex necrosis virus (ToANV) is a new virus that causes important damage in tomato crops from the Culiacan Valley, Sinaloa, Mexico. To understand the relationship between ToANV and its vector Bermisia tabaci (Hemiptera: Aleyrodidae) (Gennadius) biotype B, laboratory and greenhouse trials were completed to: 1) determine the acquisition and inoculation access periods of ToANV by B. tabaci from tomato to tomato, 2) understand the transmission efficiency at different B. tabaci population densities, 3) estimate the time from inoculation of the virus at different B. tabaci densities to manifestation of symptoms in the plants, and 4) determine the retention time of the virus by the insect vector. The presence of the virus in plants was determined by reverse transcription-polymerase chain reaction amplification ofa 795-bp fragment (GenBank JN704068), which is phylogenetically related to ToANV (GenBank EF063242). The results showed that B. tabaci is an effective vector for ToANV with relatively long acquisition (12 h) and inoculation (9 h) access periods; a single adult is capable of transmitting and retaining the virus for up to 7d, suggesting a persistent mode of transmission. These results will help in the development of management strategies for controlling the vector and the disease.

  3. RNA interference-mediated knockdown of the hydroxyacid-oxoacid transhydrogenase gene decreases thiamethoxam resistance in adults of the whitefly Bemisia tabaci

    PubMed Central

    Yang, Xin; Xie, Wen; Li, Ru-mei; Zhou, Xiao-mao; Wang, Shao-li; Wu, Qing-jun; Yang, Ni-na; Xia, Ji-xing; Yang, Ze-zong; Guo, Li-tao; Liu, Ya-ting; Zhang, You-jun

    2017-01-01

    Bemisia tabaci has developed a high level of resistance to thiamethoxam, a second generation neonicotinoid insecticide that has been widely used to control this pest. In this study, we investigated whether hydroxyacid-oxoacid transhydrogenase (HOT) is involved in resistance to the neonicotinoid insecticide thiamethoxam in the whitefly. We cloned the full-length gene that encodes HOT in B. tabaci. Its cDNA contains a 1428-bp open reading frame encoding 475 amino acid residues. Then we evaluated the mRNA expression level of HOT in different developmental stages, and found HOT expression was significantly greater in thiamethoxam resistance adults than in thiamethoxam susceptible adults. Subsequently, seven field populations of B. tabaci adults were sampled, the expression of mRNA level of HOT significant positive correlated with thiamethoxam resistance level. At last, we used a modified gene silencing system to knock-down HOT expression in B. tabaci adults. The results showed that the HOT mRNA levels decreased by 57% and thiamethoxam resistance decreased significantly after 2 days of feeding on a diet containing HOT dsRNA. The results indicated that down-regulation of HOT expression decreases thiamethoxam resistance in B. tabaci adults. PMID:28117358

  4. RNA interference-mediated knockdown of the hydroxyacid-oxoacid transhydrogenase gene decreases thiamethoxam resistance in adults of the whitefly Bemisia tabaci.

    PubMed

    Yang, Xin; Xie, Wen; Li, Ru-Mei; Zhou, Xiao-Mao; Wang, Shao-Li; Wu, Qing-Jun; Yang, Ni-Na; Xia, Ji-Xing; Yang, Ze-Zong; Guo, Li-Tao; Liu, Ya-Ting; Zhang, You-Jun

    2017-01-24

    Bemisia tabaci has developed a high level of resistance to thiamethoxam, a second generation neonicotinoid insecticide that has been widely used to control this pest. In this study, we investigated whether hydroxyacid-oxoacid transhydrogenase (HOT) is involved in resistance to the neonicotinoid insecticide thiamethoxam in the whitefly. We cloned the full-length gene that encodes HOT in B. tabaci. Its cDNA contains a 1428-bp open reading frame encoding 475 amino acid residues. Then we evaluated the mRNA expression level of HOT in different developmental stages, and found HOT expression was significantly greater in thiamethoxam resistance adults than in thiamethoxam susceptible adults. Subsequently, seven field populations of B. tabaci adults were sampled, the expression of mRNA level of HOT significant positive correlated with thiamethoxam resistance level. At last, we used a modified gene silencing system to knock-down HOT expression in B. tabaci adults. The results showed that the HOT mRNA levels decreased by 57% and thiamethoxam resistance decreased significantly after 2 days of feeding on a diet containing HOT dsRNA. The results indicated that down-regulation of HOT expression decreases thiamethoxam resistance in B. tabaci adults.

  5. New putative cryptic species detection and genetic network analysis of Bemisia tabaci (Hempitera: Aleyrodidae) in China based on mitochondrial COI sequences.

    PubMed

    Hu, Jian; Zhang, Xiaoyun; Jiang, Zhilin; Zhang, Feifei; Liu, Yuanyuan; Li, Zhan; Zhang, Zhongkai

    2017-04-01

    The whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a cryptic species complex and widely distributed throughout tropical and subtropical regions. To understand the B. tabaci cryptic species diversity in China more comprehensively, in the year 2014 and 2016, a large-scale sampling was conducted from the famous biodiversity hotspot of China, Yunnan province. Mitochondrial cytochrome oxidase I gene sequences were used to identify new putative cryptic species. Phylogenetic analyses were performed using Bayesian methods to evaluate the position of new cryptic species in the context of the B. tabaci diversity in Asia. Two new cryptic species, China 5 and Asia V were identified. In total, 19 B. tabaci cryptic species are present in China, two invasive (MED and MEAM1) and 17 indigenous. A new sibling species of B. tabaci was first defined and reported. Based on the mtCOI sequences and haplotype network analyses, the genetic diversity of MED was far higher than MEAM1. We confirmed the exotic MED was originated from the western Mediterranean regions and first invaded into Yunnan, China. The genetic structures of other four indigenous species (Asia I, Asia II 1, Asia II 6, and China 1) with relatively wide distribution ranges in China were also discussed.

  6. Diversity and phylogenetic analysis of endosymbiotic bacteria from field caught Bemisia tabaci from different locations of North India based on 16S rDNA library screening.

    PubMed

    Singh, Shalini Thakur; Priya, Natarajan Gayatri; Kumar, Jitendra; Rana, Vipin Singh; Ellango, R; Joshi, Adita; Priyadarshini, Garima; Asokan, R; Rajagopal, Raman

    2012-03-01

    Bemisia tabaci is the major vector pest of agricultural crops all over the world. In this study we report the different bacterial endosymbionts associated with B. tabaci sampled from 14 different locations in North India. Using 16S rDNA clone library sequences we were able to identify Portiera, the primary endosymbiont of B. tabaci, and other secondary endosymbionts like Cardinium, Wolbachia, Rickettsia and Arsenophonus. Along with these we also detected Bacillus, Enterobacter, Paracoccus and Acinetobacter. These secondary endosymbionts were not uniformly distributed in all the locations. Phylogenetic analysis of 16S rDNA sequences of Cardinium, Wolbachia, Rickettsia and Arsenophonus showed that each of these bacteria form a separate cluster when compared to their respective counterparts from other parts of the world. MtCO1 gene based phylogenetic analysis showed the presence of Asia I and Asia II genetic groups of B. tabaci in N. India. The multiple correspondence analyses showed no correlation between the host genetic group and the endosymbiont diversity. These results suggest that the bacterial endosymbiont diversity of B. tabaci is much larger and complex than previously perceived and probably N. Indian strains of the bacterial symbionts could have evolved from some other ancestor.

  7. The suitability of biotypes Q and B of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) at different nymphal instars as hosts for Encarsia formosa Gahan (Hymenoptera: Aphelinidae)

    PubMed Central

    Liu, Xin; Zhang, Youjun; Xie, Wen; Wu, Qingjun

    2016-01-01

    Encarsia formosa Gahan (Hymenoptera: Aphelinidae) is a solitary endoparasitoid that is commercially reared and released for augmentative biological control of whiteflies infesting greenhouse crops. In most areas in China, the invasive and destructive whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) biotype Q has replaced B. tabaci biotype B and has become dominant between the two. A better understanding of the suitability of different nymphal instars of B. tabaci biotypes Q and B as hosts for E. formosa is needed to improve the use of this parasitoid for biological control. Parasitism of the four nymphal instars of B. tabaci biotypes Q and B by the commercial strain of E. formosa mass reared on Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae) was assessed in the laboratory. The results indicated that E. formosa parasitized and successfully developed on all instars of both biotypes but performed best on the 3rd instar of B. tabaci biotype B and on the 2nd, 3rd, and 4th instars of B. tabaci biotype Q. The host-feeding rate of the adult parasitoid was generally higher on nymphal instars of B. tabaci biotype Q than on the corresponding nymphal instars of biotype B and was significantly higher on the 2nd and 3rd instars. For both whitefly biotypes, the parasitoid’s immature developmental period was the longest on the 1st instar, intermediate on the 2nd and 3rd instars, and the shortest on the 4th instar. The parasitoid emergence rate was significantly lower on the 1st instar than on the other three instars and did not significantly differ between B. tabaci biotype B and biotype Q. Offspring longevity was greater on the 3rd and 4th instars than on the 1st instar and did not significantly differ between the two B. tabaci biotypes. The results indicate that commercially-produced E. formosa can parasitize all instars of B. tabaci biotypes B and Q, making this parasitoid a promising tool for the management of the two biotypes of B. tabaci present

  8. Direct and Indirect Impacts of Infestation of Tomato Plant by Myzus persicae (Hemiptera: Aphididae) on Bemisia tabaci (Hemiptera: Aleyrodidae)

    PubMed Central

    Tan, Xiao-Ling; Wang, Su; Ridsdill-Smith, James; Liu, Tong-Xian

    2014-01-01

    The impacts of infestation by the green peach aphid (Myzus persicae) on sweetpotato whitefly (Bemisia tabaci) settling on tomato were determined in seven separate experiments with whole plants and with detached leaves through manipulation of four factors: durations of aphid infestation, density of aphids, intervals between aphid removal after different durations of infestation and the time of whitefly release, and leaf positions on the plants. The results demonstrated that B. tabaci preferred to settle on the plant leaves that had not been infested by aphids when they had a choice. The plant leaves on which aphids were still present (direct effect) had fewer whiteflies than those previously infested by aphids (indirect effect). The whiteflies were able to settle on the plant which aphids had previously infested, and also could settle on leaves with aphids if no uninfested plants were available. Tests of direct factors revealed that duration of aphid infestation had a stronger effect on whitefly landing preference than aphid density; whitefly preference was the least when 20 aphids fed on the leaves for 72 h. Tests of indirect effects revealed that the major factor that affected whitefly preference for a host plant was the interval between the time of aphid removal after infestation and the time of whitefly release. The importance of the four factors that affected the induced plant defense against whiteflies can be arranged in the following order: time intervals between aphid removal and whitefly release > durations of aphid infestation > density of aphids > leaf positions on the plants. In conclusion, the density of aphid infestation and time for which they were feeding influenced the production of induced compounds by tomatoes, the whitefly responses to the plants, and reduced interspecific competition. PMID:24710393

  9. Tomato Pathogenesis-related Protein Genes are Expressed in Response to Trialeurodes vaporariorum and Bemisia tabaci Biotype B Feeding

    PubMed Central

    Puthoff, David P.; Holzer, Frances M.; Perring, Thomas M.

    2010-01-01

    The temporal and spatial expression of tomato wound- and defense-response genes to Bemisia tabaci biotype B (the silverleaf whitefly) and Trialeurodes vaporariorum (the greenhouse whitefly) feeding were characterized. Both species of whiteflies evoked similar changes in tomato gene expression. The levels of RNAs for the methyl jasmonic acid (MeJA)- or ethylene-regulated genes that encode the basic β-1,3-glucanase (GluB), basic chitinase (Chi9), and Pathogenesis-related protein-1 (PR-1) were monitored. GluB and Chi9 RNAs were abundant in infested leaves from the time nymphs initiated feeding (day 5). In addition, GluB RNAs accumulated in apical non-infested leaves. PR-1 RNAs also accumulated after whitefly feeding. In contrast, the ethylene- and salicylic acid (SA)-regulated Chi3 and PR-4 genes had RNAs that accumulated at low levels and GluAC RNAs that were undetectable in whitefly-infested tomato leaves. The changes in Phenylalanine ammonia lyase5 (PAL5) were variable; in some, but not all infestations, PAL5 RNAs increased in response to whitefly feeding. PAL5 RNA levels increased in response to MeJA, ethylene, and abscisic acid, and declined in response to SA. Transcripts from the wound-response genes, leucine aminopeptidase (LapA1) and proteinase inhibitor 2 (pin2), were not detected following whitefly feeding. Furthermore, whitefly infestation of transgenic LapA1:GUS tomato plants showed that whitefly feeding did not activate the LapA1 promoter, although crushing of the leaf lamina increased GUS activity up to 40 fold. These studies indicate that tomato plants perceive B. tabaci and T. vaporariorum in a manner similar to baterical pathogens and distinct from tissue-damaging insects. PMID:20927641

  10. Multiple forms of vector manipulation by a plant-infecting virus: Bemisia tabaci and tomato yellow leaf curl virus.

    PubMed

    Liu, Baiming; Preisser, Evan L; Chu, Dong; Pan, Huipeng; Xie, Wen; Wang, Shaoli; Wu, Qingjun; Zhou, Xuguo; Zhang, Youjun

    2013-05-01

    For many insect-vectored plant viruses, the relationship between feeding behavior and vector competence may prove integral to an understanding of the epidemiology of the resulting plant disease. While plant-infecting viruses are well known to change host plant physiology in a way that makes them more attractive to vectors, viral manipulation of the vectors themselves has only recently been reported. Previous research suggested that the rapid spread of Tomato yellow leaf curl virus (TYLCV) throughout China has been facilitated by its primary vector, the whitefly Bemisia tabaci. We conducted two experiments testing the impact of TYLCV infection of the host plant (tomato) and vector (B. tabaci biotypes B and Q) on whitefly feeding behavior. Whiteflies of biotypes B and Q both appeared to find TYLCV-infected plants more attractive, probing them more quickly and having a greater number of feeding bouts; this did not, however, alter the total time spent feeding. Viruliferous whiteflies fed more readily than uninfected whiteflies and spent more time salivating into sieve tube elements. Because vector salivation is essential for viral transmission, this virally mediated alteration of behavior should provide TYLCV a direct fitness benefit. This is the first report of such manipulation by a nonpropagative virus that belongs to an exclusively plant-infecting family of viruses (Geminiviridae). In the context of previous research showing that feeding on TYLCV-infected plants harms biotype B but helps biotype Q, the fact that both biotypes were equally affected by TYLCV also suggests that the virus may alter the biotype B-biotype Q competitive interaction in favor of biotype Q.

  11. Potential of entomopathogenic fungus, Isaria fumosorosea to protect potted ornamental plants against Bemisia tabaci during shipping

    USDA-ARS?s Scientific Manuscript database

    The efficacy of entomopathogenic fungus Isaria fumosoroesa has been evaluated under abiotic conditions similar to those typical for shipping of ornamental plants. When applied to a synchronized population of B. tabaci L4 nymphs on poinsettias, I. fumosorosea induced mortality even in regime of low t...

  12. Qualitative and Quantitative Differences in Herbivore-Induced Plant Volatile Blends from Tomato Plants Infested by Either Tuta absoluta or Bemisia tabaci.

    PubMed

    Silva, Diego B; Weldegergis, Berhane T; Van Loon, Joop J A; Bueno, Vanda H P

    2017-01-03

    Plants release a variety of volatile organic compounds that play multiple roles in the interactions with other plants and animals. Natural enemies of plant-feeding insects use these volatiles as cues to find their prey or host. Here, we report differences between the volatile blends of tomato plants infested with the whitefly Bemisia tabaci or the tomato borer Tuta absoluta. We compared the volatile emission of: (1) clean tomato plants; (2) tomato plants infested with T. absoluta larvae; and (3) tomato plants infested with B. tabaci adults, nymphs, and eggs. A total of 80 volatiles were recorded of which 10 occurred consistently only in the headspace of T. absoluta-infested plants. Many of the compounds detected in the headspace of the two herbivory treatments were emitted at different rates. Plants damaged by T. absoluta emitted at least 10 times higher levels of many compounds compared to plants damaged by B. tabaci and intact plants. The multivariate separation of T. absoluta-infested plants from those infested with B. tabaci was due largely to the chorismate-derived compounds as well as volatile metabolites of C18-fatty acids and branched chain amino acids that had higher emission rates from T. absoluta-infested plants, whereas the cyclic sesquiterpenes α- and β-copaene, valencene, and aristolochene were emitted at significantly higher levels from B. tabaci-infested plants. Our findings imply that feeding by T. absoluta and B. tabaci induced emission of volatile blends that differ quantitatively and qualitatively, providing a chemical basis for the recently documented behavioral discrimination by two generalist predatory mirid species, natural enemies of T. absoluta and B. tabaci employed in biological control.

  13. Effects of Host Sex, Plant Species, and Putative Host Species on the Prevalence of Wolbachia in Natural Populations of Bemisia tabaci (Hemiptera: Aleyrodidae): A Modified Nested PCR Study.

    PubMed

    Ji, Han-Le; Qi, Lan-Da; Hong, Xiao-Yue; Xie, Hong-Fang; Li, Yuan-Xi

    2015-02-01

    Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a globally distributed pest. One of the key endosymbionts in B. tabaci is Wolbachia, an α-proteobacterium implicated in many important biological processes. Previous studies indicated that the infection frequency of Wolbachia in Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED) varied greatly among populations in different areas. However, little is known about the factors that influence the prevalence of Wolbachia in B. tabaci. In this paper, 25 field populations were collected from different locations in China, and 1,161 individuals were screened for the presence of Wolbachia using a nested polymerase chain reaction (PCR)-based method, which targets the wsp gene, to confirm Wolbachia infection status. The prevalence of Wolbachia ranged from 1.54 to 66.67% within the 25 field populations, and the infection frequency of Wolbachia was affected significantly by the putative species of B. tabaci. The infection frequency (51.55%) of Wolbachia was significantly greater in native species than in the MED (25.65%) and MEAM1 (14.37%). With the exception of host plant, all factors, including putative species, geographic location, and the sex of the host, affected the Wolbachia infection frequency in whiteflies. Six Wolbachia strains were found and clustered into four distinct clades upon phylogenetic analyses. Furthermore, Wolbachia in B. tabaci have close relationships with those from other host species, including Liriomyza trifolii (Burgess), Sogatella furcifera (Horvath), Nilaparvata lugens (Stål), and Culex pipiens L. The results demonstrated the variation and diversity of Wolbachia in B. tabaci field populations, and that the application of nested PCR extended our knowledge of Wolbachia infection in B. tabaci, especially in invasive whiteflies. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. New Insecticides for Management of Tomato Yellow Leaf Curl, a Virus Vectored by the Silverleaf Whitefly, Bemisia tabaci

    PubMed Central

    Smith, H. A.; Giurcanu, M. C.

    2014-01-01

    Greenhouse studies using a randomized complete block design were carried out to evaluate the effect of six insecticides on transmission of Tomato yellow leaf curl virus (TYLCV) by the silverleaf whitefly, Bemisia tabaci biotype B Gennadius (Hemiptera: Aleyrodidae) to tomato, Lycopersicon esculentum (Miller) (Solanales: Solanaceae), seedlings that were inoculated with whiteflies from a TYLCV colony in cages 3, 7, or 14 d after treatment with insecticide. The purpose was to reveal differences in residual efficacy of four materials that are nearing registration for use on tomato—cyazypyr, flupyradifurone, pyrafluquinazon, and sulfoxaflor—and to compare them with two established insecticides, pymetrozine and a zeta-cypermethrin/bifenthrin combination. Differences in efficacy were expected because these six materials represent five distinct modes of action and both contact and systemic materials. Percentage of tomato seedlings expressing virus symptoms tended to be lowest in seedlings treated with flupyradifurone. The zeta-cypermethrin/bifenthrin insecticide demonstrated comparable efficacy to flupyradifurone in some trials at 3 and 7 d after treatment inoculations, but not the 14 d after treatment inoculation. Pyrafluquinazon was not statistically different from cyazypyr or sulfoxaflor in percentage of plants with virus symptoms in any trial. Percentage virus in the cyazypyr and sulfoxaflor treatments was not statistically different in the 3 and 7 d after treatment inoculations. Among seedlings treated with insecticide, percentage with virus symptoms tended to be highest in the seedlings treated with pymetrozine. PMID:25368089

  15. New insecticides for management of tomato yellow leaf curl, a virus vectored by the silverleaf whitefly, Bemisia tabaci.

    PubMed

    Smith, H A; Giurcanu, M C

    2014-01-01

    Greenhouse studies using a randomized complete block design were carried out to evaluate the effect of six insecticides on transmission of Tomato yellow leaf curl virus (TYLCV) by the silverleaf whitefly, Bemisia tabaci biotype B Gennadius (Hemiptera: Aleyrodidae) to tomato, Lycopersicon esculentum (Miller) (Solanales: Solanaceae), seedlings that were inoculated with whiteflies from a TYLCV colony in cages 3, 7, or 14 d after treatment with insecticide. The purpose was to reveal differences in residual efficacy of four materials that are nearing registration for use on tomato-cyazypyr, flupyradifurone, pyrafluquinazon, and sulfoxaflor-and to compare them with two established insecticides, pymetrozine and a zeta-cypermethrin/bifenthrin combination. Differences in efficacy were expected because these six materials represent five distinct modes of action and both contact and systemic materials. Percentage of tomato seedlings expressing virus symptoms tended to be lowest in seedlings treated with flupyradifurone. The zeta-cypermethrin/bifenthrin insecticide demonstrated comparable efficacy to flupyradifurone in some trials at 3 and 7 d after treatment inoculations, but not the 14 d after treatment inoculation. Pyrafluquinazon was not statistically different from cyazypyr or sulfoxaflor in percentage of plants with virus symptoms in any trial. Percentage virus in the cyazypyr and sulfoxaflor treatments was not statistically different in the 3 and 7 d after treatment inoculations. Among seedlings treated with insecticide, percentage with virus symptoms tended to be highest in the seedlings treated with pymetrozine. © The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.

  16. Dynamics of Bemisia tabaci biotypes and insecticide resistance in Fujian province in China during 2005–2014

    PubMed Central

    Yao, Feng-Luan; Zheng, Yu; Huang, Xiao-Yan; Ding, Xue-Ling; Zhao, Jian-Wei; Desneux, Nicolas; He, Yu-Xian; Weng, Qi-Yong

    2017-01-01

    The whitefly Bemisia tabaci (Gennadius) is an important agricultural insect pest worldwide. The B and Q biotypes are the two most predominant and devastating biotypes prevalent across China. However, there are few studies regarding the occurrence of the Q biotype in Fujian Province, China, where high insecticide resistance has been reported in the B biotype. Differences in some biological characteristics between the B and Q biotypes, especially insecticide resistance, are considered to affect the outcome of their competition. Extensive surveys in Fujian revealed that the B biotype was predominant during 2005–2014, whereas the Q biotype was first detected in some locations in 2013 and widely detected throughout the province in 2014. Resistance to neonicotinoids (that have been used for more than 10 years) exhibited fluctuations in open fields, but showed a continual increasing trend in protected areas. Resistance to lambda-cyhalothrin, chlorpyrifos, and abamectin exhibited a declining trend. Resistance to novel insecticides, such as nitenpyram, pymetrozine, sulfoxaflor, and cyantraniliprole, in 2014 was generally below a moderate level. A decline in insecticide resistance in the B biotype and the rapid buildup of protected crops under global temperature increase may have promoted the establishment of the Q biotype in Fujian. PMID:28112233

  17. Dynamics of Bemisia tabaci biotypes and insecticide resistance in Fujian province in China during 2005-2014.

    PubMed

    Yao, Feng-Luan; Zheng, Yu; Huang, Xiao-Yan; Ding, Xue-Ling; Zhao, Jian-Wei; Desneux, Nicolas; He, Yu-Xian; Weng, Qi-Yong

    2017-01-23

    The whitefly Bemisia tabaci (Gennadius) is an important agricultural insect pest worldwide. The B and Q biotypes are the two most predominant and devastating biotypes prevalent across China. However, there are few studies regarding the occurrence of the Q biotype in Fujian Province, China, where high insecticide resistance has been reported in the B biotype. Differences in some biological characteristics between the B and Q biotypes, especially insecticide resistance, are considered to affect the outcome of their competition. Extensive surveys in Fujian revealed that the B biotype was predominant during 2005-2014, whereas the Q biotype was first detected in some locations in 2013 and widely detected throughout the province in 2014. Resistance to neonicotinoids (that have been used for more than 10 years) exhibited fluctuations in open fields, but showed a continual increasing trend in protected areas. Resistance to lambda-cyhalothrin, chlorpyrifos, and abamectin exhibited a declining trend. Resistance to novel insecticides, such as nitenpyram, pymetrozine, sulfoxaflor, and cyantraniliprole, in 2014 was generally below a moderate level. A decline in insecticide resistance in the B biotype and the rapid buildup of protected crops under global temperature increase may have promoted the establishment of the Q biotype in Fujian.

  18. Use of the synergist piperonyl butoxide can slow the development of alpha-cypermethrin resistance in the whitefly Bemisia tabaci.

    PubMed

    Zimmer, C T; Panini, M; Singh, K S; Randall, E L; Field, L M; Roditakis, E; Mazzoni, E; Bass, C

    2017-04-01

    The development of insecticide resistance in insect pests of crops is a growing threat to sustainable food production, and strategies that slow the development of resistance are therefore urgently required. The insecticide synergist piperonyl butoxide (PBO) inhibits certain insect detoxification systems and so may delay the evolution of metabolic resistance. In the current study we characterized resistance development in the silverleaf whitefly, Bemisia tabaci, after selection with either a neonicotinoid (thiacloprid) or pyrethroid (alpha-cypermethrin) insecticide alone or in combination with PBO. Resistance development was significantly suppressed (> 60%) in the line selected with alpha-cypermethrin + PBO compared to the line selected with alpha-cypermethrin alone. RNA sequencing (RNAseq) analyses revealed an increase in frequency of a knock-down resistance mutation but no differentially expressed genes were identified that could explain the sensitivity shift. No significant difference was observed in the level of resistance between the thiacloprid and thiacloprid + PBO selected lines, and RNA sequencing (RNAseq) analyses revealed that the cytochrome P450 monooxygenase CYP6CM1, known to metabolize neonicotinoids, was significantly upregulated (>10-fold) in both lines. The findings of this study demonstrate that PBO used in combination with certain insecticides can suppress the development of resistance in a laboratory setting; however, the mechanism by which PBO supresses resistance development remains unclear.

  19. Preference of Bemisia tabaci biotype B on zucchini squash and buckwheat and the effect of Delphastus catalinae on whitefly populations.

    PubMed

    Razze, Janine M; Liburd, Oscar E; McSorley, Robert

    2016-07-01

    Zucchini squash, Cucurbita pepo L., is an important vegetable crop in Florida. Physiological disorders and insect-transmitted diseases are major problems for squash growers in semi-tropical regions around the world. Bemisia tabaci (Gennadius) biotype B is a significant whitefly pest and is largely responsible for transmitting viruses and causing physiological disorders in squash. Several studies have shown that whitefly populations are reduced when crops are interplanted with non-host cover crops or mulches. The aim of the present study was to determine how the presence of buckwheat, Fagopyrum esculentum Moench, and a key predator, Delphastus catalinae (Horn), affect whitefly colonization on squash. Whitefly densities were higher on squash than on buckwheat. The introduction of D. catalinae on squash significantly reduced whitefly populations. Overall, there were higher densities of D. catalinae on squash where the whitefly pest was more concentrated compared with buckwheat. The study provided preliminary evidence that D. catalinae, when used in conjunction with buckwheat as a living mulch, may aid in reducing whiteflies in squash. This greenhouse experiment highlights the need to investigate a multitactic approach of intercropping buckwheat with squash and the incorporation of D. catalinae in the field to manage populations of whiteflies and whitefly-transmitted diseases. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  20. Comparison of transmission of Papaya leaf curl China virus among four cryptic species of the whitefly Bemisia tabaci complex

    PubMed Central

    Guo, Tao; Guo, Qi; Cui, Xi-Yun; Liu, Yin-Quan; Hu, Jian; Liu, Shu-Sheng

    2015-01-01

    Begomoviruses are transmitted by cryptic species of the whitefly Bemisia tabaci complex, often in a species-specific manner. Papaya leaf curl China virus (PaLCuCNV) has been recorded to infect several crops including papaya, tomato and tobacco in China. To help assess the risks of spread of this virus, we compared the acquisition, retention and transmission of PaLCuCNV among four species of whiteflies, Middle East-Asia Minor 1 (MEAM1), Mediterranean (MED), Asia 1 and Asia II 7. All four species of whiteflies are able to acquire, retain and transmit the virus, but with different levels of efficiency. Transmission tests using tomato as the host plant showed that MEAM1 transmitted PaLCuCNV with substantially higher efficiency than did MED, Asia 1 and Asia II 7. Furthermore, accumulation of PaLCuCNV in the whiteflies was positively associated with its efficiency of transmitting the virus. Altogether, these findings indicate that MEAM1 is the most efficient vector for PaLCuCNV in the four species of whiteflies, and suggest that risks of PaLCuCNV pandemics are high in regions where MEAM1 occurs. PMID:26486606

  1. Detection of resistance, cross-resistance, and stability of resistance to new chemistry insecticides in Bemisia tabaci (Homoptera: Aleyrodidae).

    PubMed

    Basit, Muhammad; Saeed, Shafqat; Saleem, Mushtaq Ahmad; Denholm, Ian; Shah, Maqbool

    2013-06-01

    Resistance levels in whitefly, Bemisia tabaci (Gennadius) collections from cotton and sunflower (up to four districts) for five neonicotinoids and two insect growth regulators (IGRs) were investigated for two consecutive years. Based on the LC50(s), all collections showed slight to moderate levels of resistance for the tested insecticides compared with the laboratory susceptible population. The data also indicated that cotton and sunflower collections had similar resistance levels. In comparison (four collections), Vehari collections showed higher resistance for acetamiprid, thiacloprid, and nitenpyram compared with those of others. Average resistance ratios for acetamiprid, thiacloprid, and nitenpyram ranged from 5- to 13-, 4- to 8-, and 9- to 13-fold, respectively. Multan and Vehari collections also exhibited moderate levels (9- to 16-fold) of resistance to buprofezin. Furthermore, toxicity of neonicotinoids against immature stages was equal to that of insect growth regulators. The data also suggested that resistance in the field populations was stable. After selection for four generations with bifenthrin (G1 to G4), resistance to bifenthrin increased to 14-fold compared with the laboratory susceptible population. Selection also increased resistance to fenpropathrin, lambdacyhalothrin, imidacloprid, acetamiprid, and diafenthuron. Cross-resistance and stability of resistance in the field populations is of some concern. Rotation of insecticides having no cross-resistance and targeting the control against immature stages may control the resistant insects, simultaneously reducing the selection pressure imposed.

  2. Comparison of transmission of Papaya leaf curl China virus among four cryptic species of the whitefly Bemisia tabaci complex.

    PubMed

    Guo, Tao; Guo, Qi; Cui, Xi-Yun; Liu, Yin-Quan; Hu, Jian; Liu, Shu-Sheng

    2015-10-21

    Begomoviruses are transmitted by cryptic species of the whitefly Bemisia tabaci complex, often in a species-specific manner. Papaya leaf curl China virus (PaLCuCNV) has been recorded to infect several crops including papaya, tomato and tobacco in China. To help assess the risks of spread of this virus, we compared the acquisition, retention and transmission of PaLCuCNV among four species of whiteflies, Middle East-Asia Minor 1 (MEAM1), Mediterranean (MED), Asia 1 and Asia II 7. All four species of whiteflies are able to acquire, retain and transmit the virus, but with different levels of efficiency. Transmission tests using tomato as the host plant showed that MEAM1 transmitted PaLCuCNV with substantially higher efficiency than did MED, Asia 1 and Asia II 7. Furthermore, accumulation of PaLCuCNV in the whiteflies was positively associated with its efficiency of transmitting the virus. Altogether, these findings indicate that MEAM1 is the most efficient vector for PaLCuCNV in the four species of whiteflies, and suggest that risks of PaLCuCNV pandemics are high in regions where MEAM1 occurs.

  3. Selection of endogenous reference genes for gene expression analysis in the Mediterranean species of the Bemisia tabaci (Hemiptera: Aleyrodidae) complex.

    PubMed

    Su, Yun; He, Wen-Bo; Wang, Jia; Li, Jun-Min; Liu, Shu-Sheng; Wang, Xiao-Wei

    2013-06-01

    Quantitative real-time reverse transcription polymerase chain reaction is widely used for gene expression analysis, and robust normalization against stably expressed endogenous reference genes (ERGs) is necessary to obtain accurate results. In this study, the stability of nine housekeeping genes of the sweetpotato whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae) Mediterranean were evaluated in various conditions by quantitative real-time reverse transcription polymerase chain reaction using geNorm and Normfinder programs. Both programs suggested alpha-tubulin/ubiquitin and 18S small subunit ribosomal RNA the most stable genes for bacterium- and insecticide-treated whiteflies, respectively. For developmental stages, organs, and the samples including salivary glands and the whole body, transcription initiation factor TFIID subunit was calculated as the most stably expressed gene by both programs. In addition, we compared the RNA-seq data with the results of geNorm and Normfinder and found that the stable genes revealed by RNA-seq analysis were also the ERGs recommended by geNorm and Normfinder. Furthermore, the use of the most stable gene suggested by RNA-seq analysis as an ERG produced similar gene expression patterns compared with results generated from the normalization against the most stable gene selected by geNorm and Normfinder and multiple genes recommended by geNorm. It indicates that RNA-seq data are reliable and provide a great source for ERG candidate exploration. Our results benefit future research on gene expression profiles of whiteflies and possibly other organisms.

  4. [Biology and non-preference for oviposition by Bemisia tabaci (Gennadius) biotype B (Hemiptera: Aleyrodidae) on cotton cultivars].

    PubMed

    Torres, Lucas C; Souza, Brígida; Amaral, Bruno B; Tanque, Ricardo L

    2007-01-01

    The purposes of this work were to evaluate some biological aspects of Bemisia tabaci (Gennadius) biotype B at egg and nymphal stages and to evaluate the non-preference for oviposition and its correlation with the number and type of trichomes on the cotton cultivars BRS Ipê, BRS 186-Precoce 3, BRS Acala, BRS Verde, BRS-200 Marrom, BRS Cedro, BRS Ita 90-2 and BRS Aroeira. The experiments were conducted in climatic chambers at 28 +/- 2 degrees C, 70% RH and photophase of 14h, and in greenhouse. Egg fertility was not affected by the cotton cultivars but survival in egg-adult period was influenced by the host plant. There was no influence of cultivars neither on the duration of egg stage, nymphs at 2nd, 3rd and 4th instars nor on the duration from egg to adult, but nymphs reared on the cultivar BRS Ipê had their 1st instar extended. Low number of eggs was detected on the cultivars BRS Aroeira, BRS Verde and BRS Ita 90-2 in both experiments with and without oviposition choice, indicating a possible mechanism of resistance, but no correlation could be established between trichome densisty and oviposition non-preference.

  5. Dissipation rate of thiacloprid and its control effect against Bemisia tabaci in greenhouse tomato after soil application.

    PubMed

    Dong, Sa; Qiao, Kang; Wang, Hongyan; Zhu, Yukun; Xia, Xiaoming; Wang, Kaiyun

    2014-08-01

    Thiacloprid is a chloronicotinyl insecticide that is quite effective against sucking insects. In this study, when thiacloprid was applied at two different rates (normal rate 15 kg ha(-1) , double rate 30 kg ha(-1) ), the systemic distribution and residue of thiacloprid as well as its control effect against whitefly (Bemisia tabaci) were investigated in greenhouse tomato after soil application. The results showed that thiacloprid was present in the tomato leaves until day 25, and then its amount was less than 0.005 mg kg(-1) and could not be detected. Thiacloprid residue in the tomato stems basically remained at a stable low level throughout the experimental period. Thiacloprid in soil had half-lives of 11.8 and 12.5 days for the normal treatment and the double treatment respectively. The control efficiency of whiteflies was about 90% from day 1 to day 10. This was followed by a slow decline, but efficiency was still higher than 50% until day 21. In addition, no significant differences were noted in the control effect of thiacloprid on whiteflies between the two different rates. Soil application of thiacloprid at the normal rate can effectively control whiteflies, with high efficiency and long persistence. © 2013 Society of Chemical Industry.

  6. Rapid genetic turnover in populations of the insect pest Bemisia tabaci Middle East: Asia Minor 1 in an agricultural landscape.

    PubMed

    Dinsdale, A; Schellhorn, N A; De Barro, P; Buckley, Y M; Riginos, C

    2012-10-01

    Organisms differ greatly in dispersal ability, and landscapes differ in amenability to an organism's movement. Thus, landscape structure and heterogeneity can affect genetic composition of populations. While many agricultural pests are known for their ability to disperse rapidly, it is unclear how fast and over what spatial scale insect pests might respond to the temporally dynamic agricultural landscapes they inhabit. We used population genetic analyses of a severe crop pest, a member of the Bemisia tabaci (Hemiptera: Sternorrhyncha: Aleyrodoidea: Aleyrodidea) cryptic species complex known as Middle East-Asia Minor 1 (commonly known as biotype B), to estimate spatial and temporal genetic diversity over four months of the 2006-2007 summer growing season. We examined 559 individuals from eight sites, which were scored for eight microsatellite loci. Temporal genetic structure greatly exceeded spatial structure. There was significant temporal change in local genetic composition from the beginning to the end of the season accompanied by heterozygote deficits and inbreeding. This temporal structure suggests entire cohorts of pests can occupy a large and variable agricultural landscape but are rapidly replaced. These rapid genetic fluctuations reinforce the concept that agricultural landscapes are dynamic mosaics in time and space and may contribute to better decisions for pest and insecticide resistance management.

  7. The Whitefly Bemisia tabaci Knottin-1 Gene Is Implicated in Regulating the Quantity of Tomato Yellow Leaf Curl Virus Ingested and Transmitted by the Insect.

    PubMed

    Hariton Shalev, Aliza; Sobol, Iris; Ghanim, Murad; Liu, Shu-Sheng; Czosnek, Henryk

    2016-07-22

    The whitefly Bemisia tabaci is a major pest to agricultural crops. It transmits begomoviruses, such as Tomato yellow leaf curl virus (TYLCV), in a circular, persistent fashion. Transcriptome analyses revealed that B. tabaci knottin genes were responsive to various stresses. Upon ingestion of tomato begomoviruses, two of the four knottin genes were upregulated, knot-1 (with the highest expression) and knot-3. In this study, we examined the involvement of B. tabaci knottin genes in relation to TYLCV circulative transmission. Knottins were silenced by feeding whiteflies with knottin dsRNA via detached tomato leaves. Large amounts of knot-1 transcripts were present in the abdomen of whiteflies, an obligatory transit site of begomoviruses in their circulative transmission pathway; knot-1 silencing significantly depleted the abdomen from knot-1 transcripts. Knot-1 silencing led to an increase in the amounts of TYLCV ingested by the insects and transmitted to tomato test plants by several orders of magnitude. This effect was not observed following knot-3 silencing. Hence, knot-1 plays a role in restricting the quantity of virions an insect may acquire and transmit. We suggest that knot-1 protects B. tabaci against deleterious effects caused by TYLCV by limiting the amount of virus associated with the whitefly vector.

  8. The Whitefly Bemisia tabaci Knottin-1 Gene Is Implicated in Regulating the Quantity of Tomato Yellow Leaf Curl Virus Ingested and Transmitted by the Insect

    PubMed Central

    Hariton Shalev, Aliza; Sobol, Iris; Ghanim, Murad; Liu, Shu-Sheng; Czosnek, Henryk

    2016-01-01

    The whitefly Bemisia tabaci is a major pest to agricultural crops. It transmits begomoviruses, such as Tomato yellow leaf curl virus (TYLCV), in a circular, persistent fashion. Transcriptome analyses revealed that B. tabaci knottin genes were responsive to various stresses. Upon ingestion of tomato begomoviruses, two of the four knottin genes were upregulated, knot-1 (with the highest expression) and knot-3. In this study, we examined the involvement of B. tabaci knottin genes in relation to TYLCV circulative transmission. Knottins were silenced by feeding whiteflies with knottin dsRNA via detached tomato leaves. Large amounts of knot-1 transcripts were present in the abdomen of whiteflies, an obligatory transit site of begomoviruses in their circulative transmission pathway; knot-1 silencing significantly depleted the abdomen from knot-1 transcripts. Knot-1 silencing led to an increase in the amounts of TYLCV ingested by the insects and transmitted to tomato test plants by several orders of magnitude. This effect was not observed following knot-3 silencing. Hence, knot-1 plays a role in restricting the quantity of virions an insect may acquire and transmit. We suggest that knot-1 protects B. tabaci against deleterious effects caused by TYLCV by limiting the amount of virus associated with the whitefly vector. PMID:27455309

  9. Insecticide resistance status in the whitefly, Bemisia tabaci genetic groups Asia-I, Asia-II-1 and Asia-II-7 on the Indian subcontinent

    PubMed Central

    Naveen, N. C.; Chaubey, Rahul; Kumar, Dinesh; Rebijith, K. B.; Rajagopal, Raman; Subrahmanyam, B.; Subramanian, S.

    2017-01-01

    The present study is a summary of the current level of the insecticide resistance to selected organophosphates, pyrethroids, and neonicotinoids in seven Indian field populations of Bemisia tabaci genetic groups Asia-I, Asia-II-1, and Asia-II-7. Susceptibility of these populations was varied with Asia-II-7 being the most susceptible, while Asia-I and Asia-II-1 populations were showing significant resistance to these insecticides. The variability of the LC50 values was 7x for imidacloprid and thiamethoxam, 5x for monocrotophos and 3x for cypermethrin among the Asia-I, while, they were 7x for cypermethrin, 6x for deltamethrin and 5x for imidacloprid within the Asia-II-1 populations. When compared with the most susceptible, PUSA population (Asia-II-7), a substantial increase in resistant ratios was observed in both the populations of Asia-I and Asia-II-1. Comparative analysis during 2010–13 revealed a decline in susceptibility in Asia-I and Asia-II-1 populations of B. tabaci to the tested organophosphate, pyrethroid, and neonicotinoid insecticides. Evidence of potential control failure was detected using probit analysis estimates for cypermethrin, deltamethrin, monocrotophos and imidacloprid. Our results update resistance status of B. tabaci in India. The implications of insecticide resistance management of B. tabaci on Indian subcontinent are discussed. PMID:28098188

  10. Variation in tomato host response to Bemisia tabaci (Hemiptera: Aleyrodidae) in relation to acyl sugar content and presence of the nematode and potato aphid resistance gene Mi.

    PubMed

    Nombela, G; Beitia, F; Muñiz, M

    2000-04-01

    Two commercial cultivars of tomato, Alta and Peto 95, the accession line number LA716 of Lycopersicon pennellii and lines 94GH-006 and 94GH-033 (backcrosses between Peto 95 and LA716), with different leaf acyl sugar contents were screened for resistance to Bemisia argentifolii Bellows & Perring (corresponding to the Spanish B-biotype of Bemisia tabaci (Gennadius)), in greenhouse- and field-no-choice experiments. There was no oviposition on LA716 (with the highest acyl sugar content) while the greatest fecundity and fertility values were observed on the cultivar Alta (no acyl sugar content). However, no clear relationship was found between the low acyl sugar content in the other tomato cultivars tested and whitefly reproduction. Thus, resistance to B. tabaci did not appear to correlate with acyl sugar content below a threshold level of 37.8 microg cm-2 leaf. In a greenhouse choice-assay, B. tabaci exhibited reduced host preference and reproduction on the commercial tomato cultivars Motelle, VFN8 and Ronita all of which carry the Mi gene resistance to Meloidogyne nematodes and the aphid Macrosiphum euphorbiae (Thomas), than on the Mi-lacking cultivars Moneymaker, Rio Fuego and Roma. When data of Mi-bearing plants were pooled, the mean values for daily infestation and pupal production of B. tabaci were significantly lower than those of Mi-lacking plants. This reflected a level of antixenosis- and antibiosis-based resistance in commercial tomato and indicated that Mi, or another closely linked gene, might be implicated in a partial resistance which was not associated either with the presence of glandular trichomes or their exudates. These findings support the general hypothesis for the existence of similarities among the resistance mechanisms to whiteflies, aphids and nematodes in commercial tomato plants.

  11. Critical Feeding Periods for Last Instar Nymphal and Pharate Adults of the Whiteflies, Trialeurodes vaporariorum and Bemisia tabaci

    PubMed Central

    Gelman, Dale B.; Hu, Jing S.

    2007-01-01

    A critical feeding period is the time after which 50% of a given species of insect can be removed from its food source and complete development by undergoing adult eclosion. The critical feeding period was determined for the greenhouse white fly, Trialeurodes vaporariorum, and the sweet potato whitefly, Bemisia tabaci (Biotype B) (Homptera/Hemiptera: Aleyrodidae). Fourth (last) instar and pharate adult whiteflies were removed from green bean leaves, staged, placed on filter paper in small Petri dishes containing drops of water, and observed daily for eclosion. For T. vaporariorum reared at 25°C and L:D 16:8, 55 and 80% adult eclosion were observed when whiteflies were removed at stages 4 (0.23–0.26 mm in body depth) and 5 (≥ 0.27 mm in body depth), respectively, so that at least 50% eclosion was only achieved in this species of whitefly when adult eye development had already been initiated (in Stage 4), and 80% eclosion when adult wing development had been initiated (Stage 5). In contrast, 63% of B. tabaci emerged as adults if removed from the leaf at Stage 3 (0.18–0.22 mm in body depth), and 80% emerged if removed at Stage 4/5, stages in which adult formation had not yet been initiated. The mean number of eggs laid by experimental (those removed at Stages 4–5, 6–7 or 8–9) and control (those that remained on the leaf prior to eclosion) whiteflies, and the mean percent hatch of these eggs were not significantly different in experimental and control groups. Stages 7, 8 and 9 are characterized by a light red adult eye, medium red bipartite adult eye and dark red or red-black bipartite adult eye, respectively. Mean adult longevity also was not significantly different between experimental and control groups. However, for all groups of T. vaporariorum, adult female longevity was significantly (at least 2 times) greater than male longevity. Our results identify the critical feeding periods for last instar/pharate adults of two important pest species of

  12. Critical feeding periods for last instar nymphal and pharate adults of the whiteflies, Trialeurodes vaporariorum and Bemisia tabaci.

    PubMed

    Gelman, Dale B; Hu, Jing S

    2007-01-01

    A critical feeding period is the time after which 50% of a given species of insect can be removed from its food source and complete development by undergoing adult eclosion. The critical feeding period was determined for the greenhouse white fly, Trialeurodes vaporariorum, and the sweet potato whitefly, Bemisia tabaci (Biotype B) (Homptera/Hemiptera: Aleyrodidae). Fourth (last) instar and pharate adult whiteflies were removed from green bean leaves, staged, placed on filter paper in small Petri dishes containing drops of water, and observed daily for eclosion. For T. vaporariorum reared at 25 degrees C and L:D 16:8, 55 and 80% adult eclosion were observed when whiteflies were removed at stages 4 (0.23-0.26 mm in body depth) and 5 (> or = 0.27 mm in body depth), respectively, so that at least 50% eclosion was only achieved in this species of whitefly when adult eye development had already been initiated (in Stage 4), and 80% eclosion when adult wing development had been initiated (Stage 5). In contrast, 63% of B. tabaci emerged as adults if removed from the leaf at Stage 3 (0.18-0.22 mm in body depth), and 80% emerged if removed at Stage 4/5, stages in which adult formation had not yet been initiated. The mean number of eggs laid by experimental (those removed at Stages 4-5, 6-7 or 8-9) and control (those that remained on the leaf prior to eclosion) whiteflies, and the mean percent hatch of these eggs were not significantly different in experimental and control groups. Stages 7, 8 and 9 are characterized by a light red adult eye, medium red bipartite adult eye and dark red or red-black bipartite adult eye, respectively. Mean adult longevity also was not significantly different between experimental and control groups. However, for all groups of T. vaporariorum, adult female longevity was significantly (at least 2 times) greater than male longevity. Our results identify the critical feeding periods for last instar/pharate adults of two important pest species of

  13. Investigation of the genetic diversity of an invasive whitefly (Bemisia tabaci) in China using both mitochondrial and nuclear DNA markers.

    PubMed

    Chu, D; Gao, C S; De Barro, P; Wan, F H; Zhang, Y J

    2011-08-01

    It is often considered that reduced genetic variation due to bottlenecks and founder effects limits the capacity for species to establish in new environments and subsequently spread. The recent invasion (during the past five years) of an alien whitefly, one member of Bemisia tabaci cryptic species complex, referred to as Mediterranean (herein referred to as Q-type) in Shandong Province, China, provides an ideal opportunity to study the changes in genetic variation between its home range in the Mediterranean region and its invasion range. Using both the mitochondrial cytochrome oxidase I (mtCOI) and nuclear (microsatellite) DNA, we show that Q in Shandong likely originated in the western Mediterranean. We also found that the haplotype diversity was low compared with its presumed geographic origin, whereas microsatellite allele diversity showed no such decline. A key factor in invasions is the establishment of females and so bottleneck and founder events can lead to a very rapid and considerable loss of mitochondrial diversity. The lack of haplotype diversity in Shandong supports the interpretation that, at one or more points between the western Mediterranean and China, the invading Q lost haplotype diversity, most probably through the serial process of establishment and redistribution through trade in ornamental plants. However, the loss in haplotype diversity does not necessarily mean that nuclear allelic diversity should also decline. Provided females can mate freely with whichever males are available, allelic diversity can be maintained or even increased relative to the origin of the invader. Our findings may offer some explanation to the apparent paradox between the concept of reduced genetic variation limiting adaptation to new environments and the observed low diversity in successful invaders.

  14. Genetic diversity and geographic distribution of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) genotypes associated with cassava in East Africa

    PubMed Central

    Mugerwa, Habibu; Rey, Marie E C; Alicai, Titus; Ateka, Elijah; Atuncha, Hellen; Ndunguru, Joseph; Sseruwagi, Peter

    2012-01-01

    The genetic variability of whitefly (Bemisia tabaci) species, the vectors of cassava mosaic begomoviruses (CMBs) in cassava growing areas of Kenya, Tanzania, and Uganda, was investigated through comparison of partial sequences of the mitochondria cytochrome oxidase I (mtCOI) DNA in 2010/11. Two distinct species were obtained including sub-Saharan Africa 1 (SSA1), comprising of two sub-clades (I and II), and a South West Indian Ocean Islands (SWIO) species. Among the SSA1, sub-clade I sequences shared a similarity of 97.8–99.7% with the published Uganda 1 genotypes, and diverged by 0.3–2.2%. A pairwise comparison of SSA1 sub-clade II sequences revealed a similarity of 97.2–99.5% with reference southern Africa genotypes, and diverged by 0.5–2.8%. The SSA1 sub-clade I whiteflies were widely distributed in East Africa (EA). In comparison, the SSA1 sub-clade II whiteflies were detected for the first time in the EA region, and occurred predominantly in the coast regions of Kenya, southern and coast Tanzania. They occurred in low abundance in the Lake Victoria Basin of Tanzania and were widespread in all four regions in Uganda. The SWIO species had a sequence similarity of 97.2–97.7% with the published Reunion sequence and diverged by 2.3–2.8%. The SWIO whiteflies occurred in coast Kenya only. The sub-Saharan Africa 2 whitefly species (Ug2) that was associated with the severe CMD pandemic in Uganda was not detected in our study. PMID:23170210

  15. Temporal changes of symbiont density and host fitness after rifampicin treatment in a whitefly of the Bemisia tabaci species complex.

    PubMed

    Shan, Hong-Wei; Zhang, Chang-Rong; Yan, Ting-Ting; Tang, Hai-Qin; Wang, Xiao-Wei; Liu, Shu-Sheng; Liu, Yin-Quan

    2016-04-01

    Microbial symbionts are essential or important partners to phloem-feeding insects. Antibiotics have been used to selectively eliminate symbionts from their host insects and establish host lines with or without certain symbionts for investigating functions of the symbionts. In this study, using the antibiotic rifampicin we attempted to selectively eliminate certain symbionts from a population of the Middle East-Asia Minor 1 whitefly of the Bemisia tabaci species complex, which harbors the primary symbiont "Candidatus Portiera aleyrodidarum" and two secondary symbionts "Candidatus Hamiltonella defensa" and Rickettsia. Neither the primary nor the secondary symbionts were completely depleted in the adults (F0) that fed for 48 h on a diet treated with rifampicin at concentrations of 1-100 μg/mL. However, both the primary and secondary symbionts were nearly completely depleted in the offspring (F1) of the rifampicin-treated adults. Although the F1 adults produced some eggs (F2), most of the eggs failed to hatch and none of them reached the second instar, and consequently the rifampicin-treated whitefly colony vanished at the F2 generation. Interestingly, quantitative polymerase chain reaction assays showed that in the rifampicin-treated whiteflies, the density of the primary symbiont was reduced at an obviously slower pace than the secondary symbionts. Mating experiments between rifampicin-treated and untreated adults demonstrated that the negative effects of rifampicin on host fitness were expressed when the females were treated by the antibiotic, and whether males were treated or not by the antibiotic had little contribution to the negative effects. These observations indicate that with this whitefly population it is not feasible to selectively eliminate the secondary symbionts using rifampicin without affecting the primary symbiont and establish host lines for experimental studies. However, the extinction of the whitefly colony at the second generation after

  16. The transmission efficiency of tomato yellow leaf curl virus by the whitefly Bemisia tabaci is correlated with the presence of a specific symbiotic bacterium species.

    PubMed

    Gottlieb, Yuval; Zchori-Fein, Einat; Mozes-Daube, Netta; Kontsedalov, Svetlana; Skaljac, Marisa; Brumin, Marina; Sobol, Iris; Czosnek, Henryk; Vavre, Fabrice; Fleury, Frédéric; Ghanim, Murad

    2010-09-01

    Tomato yellow leaf curl virus (TYLCV) (Geminiviridae: Begomovirus) is exclusively vectored by the whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). TYLCV transmission depends upon a 63-kDa GroEL protein produced by the vector's endosymbiotic bacteria. B. tabaci is a species complex comprising several genetically distinct biotypes that show different secondary-symbiont fauna. In Israel, the B biotype harbors Hamiltonella, and the Q biotype harbors Wolbachia and Arsenophonus. Both biotypes harbor Rickettsia and Portiera (the obligatory primary symbionts). The aim of this study was to determine which B. tabaci symbionts are involved in TYLCV transmission using B. tabaci populations collected in Israel. Virus transmission assays by B. tabaci showed that the B biotype efficiently transmits the virus, while the Q biotype scarcely transmits it. Yeast two-hybrid and protein pulldown assays showed that while the GroEL protein produced by Hamiltonella interacts with TYLCV coat protein, GroEL produced by Rickettsia and Portiera does not. To assess the role of Wolbachia and Arsenophonus GroEL proteins (GroELs), we used an immune capture PCR (IC-PCR) assay, employing in vivo- and in vitro-synthesized GroEL proteins from all symbionts and whitefly artificial feeding through membranes. Interaction between GroEL and TYLCV was found to occur in the B biotype, but not in the Q biotype. This assay further showed that release of virions protected by GroEL occurs adjacent to the primary salivary glands. Taken together, the GroEL protein produced by Hamiltonella (present in the B biotype, but absent in the Q biotype) facilitates TYLCV transmission. The other symbionts from both biotypes do not seem to be involved in transmission of this virus.

  17. Response of the polyphagous whitefly Bemisia tabaci B-biotype (Hemiptera: Aleyrodidae) to crop diversification - influence of multiple sensory stimuli on activity and fecundity.

    PubMed

    Bird, T L; Krüger, K

    2006-02-01

    A fundamental question concerning crop diversification is which mechanisms determine pest population size in polycultures compared to monocultures. It has been proposed that polyphagous insects experience a difficulty in decision-making when selecting food and oviposition sites in the presence of different host plants. This hypothesis was tested in the extremely polyphagous whitefly Bemisia tabaci (Gennadius) B-biotype, where behaviour (movement) and fecundity of females were compared in choice and no-choice experiments in the laboratory. Two parallel tests, one on different crops, including cucumber, bean and tomato, and one on different tomato cultivars, were conducted using both a mixture of crops and of tomato cultivars, as opposed to the same crop or cultivar respectively. Bemisia tabaci showed a distinct behavioural preference for cucumber when exposed to different crops simultaneously suggesting that B. tabaci has no difficulty in choosing a host plant, i.e. in making a decision, when one of the plants offered in the choice test is a high-ranking host plant. Conversely, when only low-ranking hosts of similar, but not identical, signatures were present, female whiteflies appeared to have difficulty in making a decision, resulting in increased movement and reduced fecundity. This is consistent with both the hypothesis that polyphagous insects have a problem selecting a host plant when given multiple choices and with the hierarchy threshold model, under which egg loads are lessened between periods of searching for better host plants. The study illustrates how insect behaviour can be affected by inter-cropping not only with different crops, but also with different cultivars of the same crop, thus potentially providing a simple and efficient way of reducing whitefly population build-up.

  18. A novel Wolbachia strain from the rice moth Corcyra cephalonica induces reproductive incompatibility in the whitefly Bemisia tabaci: sequence typing combined with phenotypic evidence.

    PubMed

    Hu, Hong-Yan; Li, Zheng-Xi

    2015-06-01

    Wolbachia are a group of maternally inherited bacteria frequently found in arthropods and filarial nematodes. They have recently attracted attention for their ecological roles in manipulating host reproduction, their potential use in biological control of pest insects and medical significance. Classification of Wolbachia strains is currently solely based on molecular methods. However, the strains even with identical sequence types may induce different host phenotypes. Here we isolated a Wolbachia strain from the rice moth Corcyra cephalonica (designated as wCcep_B_BJ), which was shown to share multilocus sequence typing and Wolbachia surface protein hypervariable region profiles with a cytoplasmic incompatibility (CI)-inducing strain in supergroup B, but the phenotype wCcep_B_BJ may induce needs to be determined. We thus transinfected it into the whitefly Bemisia tabaci harbouring an A-Wolbachia through nymphal microinjection. Fluorescent in situ hybridization demonstrated that wCcep_B_BJ was successfully transinfected into B. tabaci and transmitted to offspring through host eggs. Reciprocal cross showed that wCcep_B_BJ induced a strong bidirectional CI in the transinfected host without imposing a significant cost on female fecundity. Our results suggest that wCcep_B_BJ may be a promising strain for biocontrol of B. tabaci, an important agricultural pest insect.

  19. Identification and Evaluation of Suitable Reference Genes for Gene Expression Studies in the Whitefly Bemisia tabaci (Asia I) by Reverse Transcription Quantitative Real-Time PCR

    PubMed Central

    Collins, Carl; Patel, Mitulkumar V.; Colvin, John; Bailey, David; Seal, Susan

    2014-01-01

    This study presents a reliable method for performing reverse transcription quantitative real-time PCR (RT-qPCR) to measure gene expression in the whitefly Bemisia tabaci (Asia I) (Gennadius) (Hemiptera: Aleyrodidae), utilising suitable reference genes for data normalisation. We identified orthologs of commonly used reference genes (actin (ACT), cyclophilin 1 (CYP1), elongation factor 1α (EF1A), glyceraldehyde 3-phosphate dehydrogenase (GAPDH), ribosomal protein L13a (RPL13A), and α-tubulin (TUB1A)), measured the levels of their transcripts by RT-qPCR during development and in response to thermal stress, and evaluated their suitability as endogenous controls using geNorm, BestKeeper, and NormFinder programs. Overall, TUB1A, RPL13A, and CYP1 were the most stable reference genes during B. tabaci development, and TUB1A, GAPDH, and RPL13A were the most stable reference genes in the context of thermal stress. An analysis of the effects of reference gene choice on the transcript profile of a developmentally-regulated gene encoding vitellogenin demonstrated the importance of selecting the correct endogenous controls for RT-qPCR studies. We propose the use of TUB1A, RPL13A, and CYP1 as endogenous controls for transcript profiling studies of B. tabaci development, whereas the combination of TUB1A, GAPDH, and RPL13A should be employed for studies into thermal stress. The data presented here will assist future transcript profiling studies in whiteflies. PMID:25373210

  20. Infection of Bacterial Endosymbionts in Insects: A Comparative Study of Two Techniques viz PCR and FISH for Detection and Localization of Symbionts in Whitefly, Bemisia tabaci

    PubMed Central

    Raina, Harpreet Singh; Singh, Ambika; Popli, Sonam; Pandey, Neeti; Rajagopal, Raman

    2015-01-01

    Bacterial endosymbionts have been associated with arthropods and large number of the insect species show interaction with such bacteria. Different approaches have been used to understand such symbiont- host interactions. The whitefly, Bemisia tabaci, a highly invasive agricultural pest, harbors as many as seven different bacterial endosymbionts. These bacterial endosymbionts are known to provide various nutritional, physiological, environmental and evolutionary benefits to its insect host. In this study, we have tried to compare two techniques, Polymerase chain reaction (PCR) and Flourescence in situ Hybridisation (FISH) commonly used for identification and localization of bacterial endosymbionts in B. tabaci as it harbors one of the highest numbers of endosymbionts which have helped it in becoming a successful global invasive agricultural pest. The amplified PCR products were observed as bands on agarose gel by electrophoresis while the FISH samples were mounted on slides and observed under confocal microscope. Analysis of results obtained by these two techniques revealed the advantages of FISH over PCR. On a short note, performing FISH, using LNA probes proved to be more sensitive and informative for identification as well as localization of bacterial endosymbionts in B. tabaci than relying on PCR. This study would help in designing more efficient experiments based on much reliable detection procedure and studying the role of endosymbionts in insects. PMID:26287997

  1. Silicon influence on resistance induction against Bemisia tabaci biotype B (Genn.) (Hemiptera: Aleyrodidae) and on vegetative development in two soybean cultivars.

    PubMed

    Ferreira, R S; Moraes, J C; Antunes, C S

    2011-01-01

    The potential of populations of Bemisia tabaci (Genn.) to become resistant to insecticides has stimulated research into alternative tactics of integrated pest management such as the induction of host-plant resistance. Recent data have shown that silicon can increase the degree of resistance of host plants to insect pests. Therefore the aim of our work was to study the effects of silicon application on the vegetative development of soybean plants and on the induction of resistance to the silverleaf whitefly, B. tabaci biotype B. We performed choice and no-choice tests of oviposition preference on two soybean cultivars, IAC-19 (moderately resistant to B. tabaci biotype B) and MONSOY-8001 (susceptible), with and without application of silicon. Silicon did not affect silverleaf whitefly oviposition preferences, but caused significant mortality in nymphs. Thus, silicon increased the degree of resistance to silverleaf whitefly. Silicon decreased the production of phenolic compounds, but did not affect lignin production. However, when applied to cultivar IAC-19, it increased the production of non-protein organic nitrogen. Silicon had no effect on the vegetative development of soybean plants, but it increased the degree of resistance to the silverleaf whitefly. We conclude that silicon applications combined with cultivar IAC-19 can significantly decrease silverleaf whitefly populations, having a positive impact both on the soybean plant and on the environment.

  2. Binding of insecticidal lectin Colocasia esculenta tuber agglutinin (CEA) to midgut receptors of Bemisia tabaci and Lipaphis erysimi provides clues to its insecticidal potential.

    PubMed

    Roy, Amit; Gupta, Sumanti; Hess, Daniel; Das, Kali Pada; Das, Sampa

    2014-07-01

    The insecticidal potential of Galanthus nivalis agglutinin-related lectins against hemipterans has been experimentally proven. However, the basis behind the toxicity of these lectins against hemipterans remains elusive. The present study elucidates the molecular basis behind insecticidal efficacy of Colocasia esculenta tuber agglutinin (CEA) against Bemisia tabaci and Lipaphis erysimi. Confocal microscopic analyses highlighted the binding of 25 kDa stable homodimeric lectin to insect midgut. Ligand blots followed by LC MS/MS analyses identified binding partners of CEA as vacuolar ATP synthase and sarcoplasmic endoplasmic reticulum type Ca(2+) ATPase from B. tabaci, and ATP synthase, heat shock protein 70 and clathrin heavy chain assembly protein from L. erysimi. Internalization of CEA into hemolymph was confirmed by Western blotting. Glycoprotein nature of the receptors was identified through glycospecific staining. Deglycosylation assay indicated the interaction of CEA with its receptors to be probably glycan mediated. Surface plasmon resonance analysis revealed the interaction kinetics between ATP synthase of B. tabaci with CEA. Pathway prediction study based on Drosophila homologs suggested the interaction of CEA with insect receptors that probably led to disruption of cellular processes causing growth retardation and loss of fecundity of target insects. Thus, the present findings strengthen our current understanding of the entomotoxic potentiality of CEA, which will facilitate its future biotechnological applications.

  3. Invasive mechanism and management strategy of Bemisia tabaci (Gennadius) biotype B: progress report of 973 Program on invasive alien species in China.

    PubMed

    Wan, FangHao; Zhang, GuiFen; Liu, ShuSheng; Luo, Chen; Chu, Dong; Zhang, YouJun; Zang, LianSheng; Jiu, Min; Lü, ZhiChuang; Cui, XuHong; Zhang, LiPing; Zhang, Fan; Zhang, QingWen; Liu, WanXue; Liang, Pei; Lei, ZhongRen; Zhang, YongJun

    2009-01-01

    Bemisia tabaci (Gennadius) biotype B, called a "superbug", is one of the most harmful biotypes of this species complex worldwide. In this report, the invasive mechanism and management of B. tabaci biotype B, based on our 5-year studies, are presented. Six B. tabaci biotypes, B, Q, ZHJ1, ZHJ2, ZHJ3 and FJ1, have been identified in China. Biotype B dominates the other biotypes in many regions of the country. Genetic diversity in biotype B might be induced by host plant, geographical conditions, and/or insecticidal application. The activities of CarE (carboxylesterase) and GSTs (glutathione-S-transferase) in biotype B reared on cucumber and squash were greater than on other host plants, which might have increased its resistance to insecticides. The higher activities of detoxification enzymes in biotype B might be induced by the secondary metabolites in host plants. Higher adaptive ability of biotype B adults to adverse conditions might be linked to the expression of heat shock protein genes. The indigenous B. tabaci biotypes were displaced by the biotype B within 225 d. The asymmetric mating interactions and mutualism between biotype B and begomoviruses via its host plants speed up widespread invasion and displacement of other biotypes. B. tabaci biotype B displaced Trialeurodes vaporariorum (Westwood) after 4-7 generations under glasshouse conditions. Greater adaptive ability of the biotype B to adverse conditions and its rapid population increase might be the reasons of its successful displacement of T. vaporariorum. Greater ability of the biotype B to switch to different host plants may enrich its host plants, which might enable it to better compete with T. vaporariorum. Native predatory natural enemies possess greater ability to suppress B. tabaci under field conditions. The kairomones in the 3rd and 4th instars of biotype B may provide an important stimulus in host searching and location by its parasitoids. The present results provide useful information in

  4. Leaf Morphological Characters Can Be a Factor for Intra-Varietal Preference of Whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) among Eggplant Varieties

    PubMed Central

    Zhang, Yi; Zhang, Chen-Yang; Liu, Tong-Xian

    2016-01-01

    The sweetpotato whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae) MEAM1, is considered a serious pest of horticultural and many other crops. While eggplant (Solanum melongena) is one of the most favored host plants, the whiteflies exhibit preferences among different varieties. We hypothesized that certain morphological leaf characteristics of different varieties, like leaf trichome density, trichome length, leaf lamina thickness and leaf color, may affect whitefly landing, feeding and oviposition. In this study, we investigated the variation in leaf morphological characters among selected eggplant varieties and evaluated the effect of these leaf characteristics in rendering eggplant varieties either susceptible or resistant to B. tabaci. We evaluated eight eggplant varieties in choice feeding tests, and we found that the varieties JinSheng Zilongchangqie (JSZ) and H149 were the highly preferred varieties with the highest numbers of whitefly adults and eggs. Significantly lower numbers of whitefly adult eggs were found on the resistant variety Tuo Lu Bamu (TLB). The varieties JinGuangbo Luqie (JGL), JinGuangbo Ziquanqie (JGZ), DaYang Ziguanqie (DYZ), QinXing Ziguanqie (QXZ), and QinXing Niuxinqie (QXN) were moderately favored by B. tabaci. Leaf trichome density, trichome length and leaf lamina thickness were positively correlated with numbers of whitefly adults and eggs. B. tabaci was less attracted to the leaves that reflect long and middle wavelength light (higher R and G values) than to the bright green leaves (medium G value), but the short wavelength light (higher B value) had no significant effect on whitefly preference. The degree of hue had a positive effect, and saturation and brightness had a negative effect on whitefly attraction. PMID:27081849

  5. Leaf Morphological Characters Can Be a Factor for Intra-Varietal Preference of Whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) among Eggplant Varieties.

    PubMed

    Hasanuzzaman, Abu Tayeb Mohammad; Islam, Md Nazrul; Zhang, Yi; Zhang, Chen-Yang; Liu, Tong-Xian

    2016-01-01

    The sweetpotato whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae) MEAM1, is considered a serious pest of horticultural and many other crops. While eggplant (Solanum melongena) is one of the most favored host plants, the whiteflies exhibit preferences among different varieties. We hypothesized that certain morphological leaf characteristics of different varieties, like leaf trichome density, trichome length, leaf lamina thickness and leaf color, may affect whitefly landing, feeding and oviposition. In this study, we investigated the variation in leaf morphological characters among selected eggplant varieties and evaluated the effect of these leaf characteristics in rendering eggplant varieties either susceptible or resistant to B. tabaci. We evaluated eight eggplant varieties in choice feeding tests, and we found that the varieties JinSheng Zilongchangqie (JSZ) and H149 were the highly preferred varieties with the highest numbers of whitefly adults and eggs. Significantly lower numbers of whitefly adult eggs were found on the resistant variety Tuo Lu Bamu (TLB). The varieties JinGuangbo Luqie (JGL), JinGuangbo Ziquanqie (JGZ), DaYang Ziguanqie (DYZ), QinXing Ziguanqie (QXZ), and QinXing Niuxinqie (QXN) were moderately favored by B. tabaci. Leaf trichome density, trichome length and leaf lamina thickness were positively correlated with numbers of whitefly adults and eggs. B. tabaci was less attracted to the leaves that reflect long and middle wavelength light (higher R and G values) than to the bright green leaves (medium G value), but the short wavelength light (higher B value) had no significant effect on whitefly preference. The degree of hue had a positive effect, and saturation and brightness had a negative effect on whitefly attraction.

  6. [Adult oviposition and larvae feeding behavior of Spodoptera litura (Lepidoptera: Noctuidae) on tobacco plants after infested by B-biotype Bemisia tabaci (Homoptera: Aleyrodidae)].

    PubMed

    Wang, Hong-Tao; Xue, Ming; Chen, Hui-Na; Zhou, Fang-Yuan

    2011-05-01

    To understand the effects of the defense responses of tobacco plants induced by the infesting of B-biotype Bemisia tabaci to Spodoptera litura, and to explore the mechanisms of the interspecific interactions between B-biotype B. tabaci and S. litura, a laboratory experiment was conducted to study the effects of tobacco plants after infested by B-biotype B. tabaci on the adult oviposition selection and the larvae feeding, anti-feeding, and other feeding behaviors of S. litura. Comparing with that on control plants, the egg number oviposited by adult S. litura on the infested plants decreased by 40.9%. The plant leaves infested had great repellent effect to the newly-hatched S. litura larvae, while the middle leaves and the leaves with systemic damage symptom (white-vein) had definite attractive effect. Unexpanded terminal leaves had no effects on the host selection of S. litura larvae. The S. litura larvae had significant anti-feeding behavior on the leaves infested, being more notable than that on the leaves with white-vein. On the leaves infested and with white-vein, the feeding times per unit duration or the feeding percentage of S. litura larvae decreased, the time of initiating feeding prolonged, and the total feeding area declined significantly, compared with the control. In conclusion, the tobacco plants after infested by B-biotype B. tabaci had negative effects on the adult oviposition and larvae feeding of S. litura, and the results of the study would be useful in understanding the population dynamics of tobacco pests and their management.

  7. Specific cells in the primary salivary glands of the whitefly Bemisia tabaci control retention and transmission of begomoviruses.

    PubMed

    Wei, Jing; Zhao, Juan-Juan; Zhang, Tong; Li, Fang-Fang; Ghanim, Murad; Zhou, Xue-Ping; Ye, Gong-Yin; Liu, Shu-Sheng; Wang, Xiao-Wei

    2014-11-01

    The majority of plant viruses are vectored by arthropods via persistent-circulative or noncirculative transmission. Previous studies have shown that specific binding sites for noncirculative viruses reside within the stylet or foregut of insect vectors, whereas the transmission mechanisms of circulative viruses remain ambiguous. Here we report the critical roles of whitefly primary salivary glands (PSGs) in the circulative transmission of two begomoviruses. The Middle East Asia Minor 1 (MEAM1) species of the whitefly Bemisia tabaci complex efficiently transmits both Tomato yellow leaf curl China virus (TYLCCNV) and Tomato yellow leaf curl virus (TYLCV), whereas the Mediterranean (MED) species transmits TYLCV but not TYLCCNV. PCR and fluorescence in situ hybridization experiments showed that TYLCCNV efficiently penetrates the PSGs of MEAM1 but not MED whiteflies. When a fragment of the coat protein of TYLCCNV was exchanged with that of TYLCV, mutated TYLCCNV accumulated in the PSGs of MED whiteflies, while mutant TYLCV was nearly undetectable. Confocal microscopy revealed that virion transport in PSGs follows specific paths to reach secretory cells in the central region, and the accumulation of virions in the secretory region of PSGs was correlated with successful virus transmission. Our findings demonstrate that whitefly PSGs, in particular the cells around the secretory region, control the specificity of begomovirus transmission. Over 75% of plant viruses are transmitted by insects. However, the mechanisms of virus transmission by insect vectors remain largely unknown. Begomoviruses and whiteflies are a complex of viruses and vectors which threaten many crops worldwide. We investigated the transmission of two begomoviruses by two whitefly species. We show that specific cells of the whitefly primary salivary glands control viral transmission specificity and that virion transport in the glands follows specific paths to reach secretory cells in the central region and

  8. Inter-seasonal population dynamics and pest status of Bemisia tabaci (Gennadius) biotype B in an Australian cropping system.

    PubMed

    Sequeira, R V; Shields, A; Moore, A; De Barro, P

    2009-08-01

    Bemisia tabaci, biotype B, commonly known as the silverleaf whitefly (SLW) is an alien species that invaded Australia in the mid-90s. This paper reports on the invasion ecology of SLW and the factors that are likely to have contributed to the first outbreak of this major pest in an Australian cotton cropping system. Population dynamics of SLW within whitefly-susceptible crop (cotton and cucurbit) and non-crop vegetation (sowthistle, Sonchus spp.) components of the cropping system were investigated over four consecutive growing seasons (September-June) 2001/02-2004/05 in the Emerald Irrigation Area (EIA) of Queensland, Australia. Based on fixed geo-referenced sampling sites, variation in spatial and temporal abundance of SLW within each system component was quantified to provide baseline data for the development of ecologically sustainable pest management strategies. Parasitism of large (3rd and 4th instars) SLW nymphs by native aphelinid wasps was quantified to determine the potential for natural control of SLW populations. Following the initial outbreak in 2001/02, SLW abundance declined and stabilised over the next three seasons. The population dynamics of SLW is characterised by inter-seasonal population cycling between the non-crop (weed) and cotton components of the EIA cropping system. Cotton was the largest sink for and source of SLW during the study period. Over-wintering populations dispersed from weed host plant sources to cotton in spring followed by a reverse dispersal in late summer and autumn to broad-leaved crops and weeds. A basic spatial source-sink analysis showed that SLW adult and nymph densities were higher in cotton fields that were closer to over-wintering weed sources throughout spring than in fields that were further away. Cucurbit fields were not significant sources of SLW and did not appear to contribute significantly to the regional population dynamics of the pest. Substantial parasitism of nymphal stages throughout the study period

  9. Specific Cells in the Primary Salivary Glands of the Whitefly Bemisia tabaci Control Retention and Transmission of Begomoviruses

    PubMed Central

    Wei, Jing; Zhao, Juan-Juan; Zhang, Tong; Li, Fang-Fang; Ghanim, Murad; Zhou, Xue-Ping; Ye, Gong-Yin

    2014-01-01

    ABSTRACT The majority of plant viruses are vectored by arthropods via persistent-circulative or noncirculative transmission. Previous studies have shown that specific binding sites for noncirculative viruses reside within the stylet or foregut of insect vectors, whereas the transmission mechanisms of circulative viruses remain ambiguous. Here we report the critical roles of whitefly primary salivary glands (PSGs) in the circulative transmission of two begomoviruses. The Middle East Asia Minor 1 (MEAM1) species of the whitefly Bemisia tabaci complex efficiently transmits both Tomato yellow leaf curl China virus (TYLCCNV) and Tomato yellow leaf curl virus (TYLCV), whereas the Mediterranean (MED) species transmits TYLCV but not TYLCCNV. PCR and fluorescence in situ hybridization experiments showed that TYLCCNV efficiently penetrates the PSGs of MEAM1 but not MED whiteflies. When a fragment of the coat protein of TYLCCNV was exchanged with that of TYLCV, mutated TYLCCNV accumulated in the PSGs of MED whiteflies, while mutant TYLCV was nearly undetectable. Confocal microscopy revealed that virion transport in PSGs follows specific paths to reach secretory cells in the central region, and the accumulation of virions in the secretory region of PSGs was correlated with successful virus transmission. Our findings demonstrate that whitefly PSGs, in particular the cells around the secretory region, control the specificity of begomovirus transmission. IMPORTANCE Over 75% of plant viruses are transmitted by insects. However, the mechanisms of virus transmission by insect vectors remain largely unknown. Begomoviruses and whiteflies are a complex of viruses and vectors which threaten many crops worldwide. We investigated the transmission of two begomoviruses by two whitefly species. We show that specific cells of the whitefly primary salivary glands control viral transmission specificity and that virion transport in the glands follows specific paths to reach secretory cells in

  10. Biochemical evaluation of interactions between synergistic molecules and phase I enzymes involved in insecticide resistance in B- and Q-type Bemisia tabaci (Hemiptera: Aleyrodidae).

    PubMed

    Panini, Michela; Tozzi, Francesco; Zimmer, Christoph T; Bass, Chris; Field, Linda; Borzatta, Valerio; Mazzoni, Emanuele; Moores, Graham

    2017-09-01

    Metabolic resistance is an important consideration in the whitefly Bemisia tabaci, where an esterase-based mechanism has been attributed to pyrethroid resistance and over-expression of the cytochrome P450, CYP6CM1, has been correlated to resistance to imidacloprid and other neonicotinoids. In vitro interactions between putative synergists and CYP6CM1, B and Q-type esterases were investigated, and structure-activity relationship analyses allowed the identification of chemical structures capable of acting as inhibitors of esterase and oxidase activities. Specifically, methylenedioxyphenyl (MDP) moieties with a polyether chain were preferable for optimum inhibition of B-type esterase, whilst corresponding dihydrobenzofuran structures were potent for the Q-esterase variation. Potent inhibition of CYP6CM1 resulted from structures which contained an alkynyl chain with a terminal methyl group. Synergist candidates could be considered for field control of B. tabaci, especially to abrogate neonicotinoid resistance. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  11. Characteristics, phenotype, and transmission of Wolbachia in the sweet potato whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae), and its parasitoid Eretmocerus sp. nr. emiratus (Hymenoptera: Aphelinidae).

    PubMed

    Chiel, Elad; Kelly, Suzanne E; Harris, Alexandre M; Gebiola, Marco; Li, Xianchun; Zchori-Fein, Einat; Hunter, Martha S

    2014-04-01

    Wolbachia is a common intracellular bacterial endosymbiont of insects, causing a variety of effects including reproductive manipulations such as cytoplasmic incompatibility (CI). In this study, we characterized Wolbachia in the whitefly Bemisia tabaci and in the whitefly parasitoid Eretmocerus sp. nr. emiratus. We also tested for horizontal transmission of Wolbachia between and within trophic levels, and we determined the phenotype of Wolbachia in E. sp. nr. emiratus. Using multilocus sequence typing and phylogenetic analyses, we found that B. tabaci and E. sp. nr. emiratus each harbor a different and unique strain of Wolbachia. Both strains belong to the phylogenetic supergroup B. No evidence for horizontal transmission of Wolbachia between and within trophic levels was found in our study system. Finally, crossing results were consistent with a CI phenotype; when Wolbachia-infected E. sp. nr. emiratus males mate with uninfected females, wasp progeny survival dropped significantly, and the number of females was halved. This is the first description of CI caused by Wolbachia in the economically important genus Eretmocerus. Our study underscores the expectation that horizontal transmission events occur rarely in the dynamics of secondary symbionts such as Wolbachia, and highlights the importance of understanding the effects of symbionts on the biology of natural enemies.

  12. Biological parameters of Bemisia tabaci (Gennadius) biotype B (Hemiptera: Aleyrodidae) on Jatropha gossypiifolia, commercial (Manihot esculenta) and wild cassava (Manihot flabellifolia and M. carthaginensis) (Euphorbiaceae).

    PubMed

    Carabalí, Arturo; Belloti, Anthony C; Montoya-Lerma, James

    2010-01-01

    Bemisia tabaci (Gennadius) is one of the most important pests of cassava in Africa and several countries of Asia due to the damage caused by direct feeding, the excretion of honeydew, and its capacity as a vector of cassava mosaic geminivirus. There is a general consensus that B. tabaci is a complex of morphologically indistinguishable populations with different biotypes. In the Americas, the polyphagous biotype B does not appear to feed on cassava. Recent studies indicate that it is possible, however, for biotype B to gradually adapt to cassava using phylogenetically related hosts. Therefore, the possibility that some wild species of cassava constitute intermediate hosts in the adaptation process may lead to the establishment of biotype B on commercial varieties of Manihot esculenta. In here, we evaluated Jatropha gossypiifolia, two wild species of cassava (Manihot flabellifolia and M. carthaginensis) and a commercial cassava variety (MCol 2063) as hosts of biotype B. The highest oviposition rate (2.7 eggs /two days) occurred on M. esculenta, although the development time (44 d) was the longest when compared to M. carthaginensis and J. gossypiifolia. About 60% of the population could reproduce on the wild cassava species vs. 55% on J. gossypiifolia and 27.5% on the commercial variety. Our data suggest that J. gossypiifolia is a suitable host and the wild species M. carthaginensis can constitute a potential intermediate host in the adaptation of biotype B to commercial varieties of cassava.

  13. The complete mitochondrial genome of Bemisia afer (Hemiptera: Aleyrodidae).

    PubMed

    Wang, Hua-Ling; Xiao, Na; Yang, Jiao; Wang, Xiao-Wei; Colvin, John; Liu, Shu-Sheng

    2016-01-01

    The length of the Bemisia afer (Priesner & Hosny) (Hemiptera: Aleyrodidae) mitochondrial genome (mitogenome) is 14,968 bp and consists of 13 protein coding genes (PCGs), 21 transfer RNAs (tRNA), 2 ribosomal RNAs and 1 control region. Apart from one serine transfer RNA gene (tRNA-Ser) which is absent, the synteny is consistent with the mitogenomes of other whitefly species. The overall base composition of the heavy strand for A, G, T and C is 28.96, 18.97, 36.7 and 15.37%, respectively, with a slight AT bias. Two rare codons (GTG and TTG) are employed as start codons by some PCGs. B. afer is a group of cryptic species. This first mitogenome cloned from African cassava B. afer, therefore, both enrich the whitefly molecular resource and will aid the sequencing of the other species' mitogenomes. It will contribute significantly to resolving the systematics of the B. afer complex.

  14. Susceptibility of MED-Q1 and MED-Q3 Biotypes of Bemisia tabaci (Hemiptera: Aleyrodidae) Populations to Essential and Seed Oils.

    PubMed

    Samuel Fogné, Drabo; Olivier, Gnankine; Bassolé, Imael H N; Nébié, Roger Charles; Laurence, Mouton

    2017-06-01

    Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a major pest of many agricultural and ornamental crops in tropical and subtropical regions causing damages that result in important economic losses. Insecticides are commonly used in greenhouses or fields to control B. tabaci populations leading to rapid evolution of resistance that render treatments inefficient. Therefore, and for environmental and human health concerns, other approaches must be developed for this pest management. In the present study, we compare, using the leaf dip method, the toxicity of three essential oils (Cymbopogon citratus, Ocimum americanum, and Hyptis spicigera) and three seed oils (Lannea microcarpa, Lannea acida, and Carapa procera) with three chemical insecticides (acetamiprid, deltamethrin, and chlorpyrifos-ethyl) on adults. Two B. tabaci biotypes (MED-Q1 and MED-Q3) belonging to the Mediterranean species and collected in Burkina Faso were used. Essential oils were analyzed by gas chromatography-mass spectrometry and gas chromatography-flame ionization detector. We showed that these two biotypes have different levels of resistance to the three insecticides, MED-Q3 being more sensitive than MED-Q1. Moreover, they differ in the frequency of resistance alleles to insecticides, especially for organophosphates, as these alleles are almost fixed in MED-Q1. On the other hand, the two biotypes prove to be more susceptible to the plant extracts than to insecticides except for chlorpyrifos-ethyl, with essential oils that showed the highest insecticidal activities. Monoterpenes content were the most abundant and showed the highest insecticidal activities. Our results indicated that essential oils, but also seed oils, have the potential to constitute an alternative strategy of pest management. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  15. Lack of cross-resistance between neonicotinoids and sulfoxaflor in field strains of Q-biotype of whitefly, Bemisia tabaci, from eastern China.

    PubMed

    Wang, Wenlong; Wang, Shaoli; Han, Guangjie; Du, Yuzhou; Wang, Jianjun

    2017-03-01

    Control of Bemisia tabaci has depended primarily and heavily on insecticides, especially neonicotinoids. The novel sulfoximine insecticide sulfoxaflor exhibits high potency against a broad range of sap-feeding insect species, including those resistant to neonicotinoids. The resistance levels of Q-biotype B. tabaci field strains collected from 8 locations in eastern China to neonicotinoids and sulfoxaflor were investigated, and single nucleotide polymorphisms (SNPs) of nicotinic acetylcholine receptor β1 subunit gene (Btβ1) were detected. Compared with the reference strain, the field strains had developed low to moderate levels of resistance to imidacloprid and nitenpyram with the resistance ratios (RR) ranging between 4.07 and 21.75-fold and 3.37 and 16.14-fold, respectively. While YZ strain exhibited high resistance (RF 40.38) to thiamethoxam, only low levels of resistance to thiamethoxam (RF 3.50-8.58) was observed in other strains. All strains were relatively susceptible to both dinotefuran (RF 0.50-2.55) and sulfoxaflor (RF 0.40-3.07). Sequence analysis of Btβ1 cDNA fragments revealed 23 SNPs representing 19 amino acid replacements in these strains. Notably, a 45bp fragment deletion was detected in JY strain, which encodes 15 amino acid residues (positions 66-80) containing arginine at position 79 (R79) corresponding to the R81T mutation in Loop D of nAChR β1 subunit in Myzus persicae resistant to neonicotinoids. The lack of cross-resistance indicates that both dinotefuran and sulfoxaflor could play an important role in the control of B. tabaci already resistant to the first and second generation neonicotinoids.

  16. Quantification and Localization of Watermelon Chlorotic Stunt Virus and Tomato Yellow Leaf Curl Virus (Geminiviridae) in Populations of Bemisia tabaci (Hemiptera, Aleyrodidae) with Differential Virus Transmission Characteristics

    PubMed Central

    Kollenberg, Mario; Winter, Stephan; Götz, Monika

    2014-01-01

    Bemisia tabaci (Gennadius) is one of the economically most damaging insects to crops in tropical and subtropical regions. Severe damage is caused by feeding and more seriously by transmitting viruses. Those of the genus begomovirus (Geminiviridae) cause the most significant crop diseases and are transmitted by B. tabaci in a persistent circulative mode, a process which is largely unknown. To analyze the translocation and to identify critical determinants for transmission, two populations of B. tabaci MEAM1 were compared for transmitting Watermelon chlorotic stunt virus (WmCSV) and Tomato yellow leaf curl virus (TYLCV). Insect populations were chosen because of their high and respectively low virus transmission efficiency to compare uptake and translocation of virus through insects. Both populations harbored Rickettsia, Hamiltonella and Wolbachia in comparable ratios indicating that endosymbionts might not contribute to the different transmission rates. Quantification by qPCR revealed that WmCSV uptake and virus concentrations in midguts and primary salivary glands were generally higher than TYLCV due to higher virus contents of the source plants. Both viruses accumulated higher in insects from the efficiently compared to the poorly transmitting population. In the latter, virus translocation into the hemolymph was delayed and virus passage was impeded with limited numbers of viruses translocated. FISH analysis confirmed these results with similar virus distribution found in excised organs of both populations. No virus accumulation was found in the midgut lumen of the poor transmitter because of a restrained virus translocation. Results suggest that the poorly transmitting population comprised insects that lacked transmission competence. Those were selected to develop a population that lacks virus transmission. Investigations with insects lacking transmission showed that virus concentrations in midguts were reduced and only negligible virus amounts were found at the

  17. [Phagodeterrent activity of the plants Tithonia diversifolia and Montanoa hibiscifolia (Asteraceae) on adults of the pest insect Bemisia tabaci (Homoptera: Aleyrodidae)].

    PubMed

    Bagnarello, Gina; Hilje, Luko; Bagnarello, Vanessa; Cartín, Victor; Calvo, Marco

    2009-12-01

    Bemisia tabaci (Gennadius) is a polyphagous, cosmopolitan and worldwide relevant pest, mainly acting as a virus vector on many crops. A sound preventive approach to deal with it would be the application of repellent or deterrent substances hopefully present in tropical plants, which in turn may contribute to take advantage of the remarkable rich Mesoamerican biodiversity. Therefore, extracts of two wild plants belonging to family Asteraceae, titonia (Tithonia diversifolia) and "tora" (Montanoa hibiscifolia), were tested for phagodeterrence to B. tabaci adults. The crude leaf extract of each one, as well as four fractions thereof (hexane, dichlorometane, ethyl acetate, and methanol) were tested under greenhouse conditions; in addition, the extracts were submitted to a phytochemical screening to determine possible metabolites causing phagodeterrence. Both restricted-choice and unrestricted-choice experiments were conducted. In the former ones, each fraction was tested at four doses (0.1, 0.5, 1.0 and 1.5% v/v), which were compared with four control treatments: distilled water, endosulfan, an agricultural oil (Aceite Agricola 81 SC), and the emulsifier Citowett. Tomato plants were sprayed and placed inside sleeve cages, where 50 B. tabaci adults were released. The criterion to appraise phagodeterrence was the number of landed adults on plants at 48h. For the unrestricted-choice experiments, only the two highest doses (1.0 and 1.5%) of the crude extracts of each species were tested, and compared to distilled water and the agricultural oil. The titonia and "tora" crude extracts caused phagodeterrence, and for both plant species the methanol fraction stood out. Results suggest that metabolites causing phagodeterrence are several sesquiterpenic lactones, polyphenolic compounds (flavonoids and tannins) and saponins.

  18. Quantification and localization of Watermelon chlorotic stunt virus and Tomato yellow leaf curl virus (Geminiviridae) in populations of Bemisia tabaci (Hemiptera, Aleyrodidae) with differential virus transmission characteristics.

    PubMed

    Kollenberg, Mario; Winter, Stephan; Götz, Monika

    2014-01-01

    Bemisia tabaci (Gennadius) is one of the economically most damaging insects to crops in tropical and subtropical regions. Severe damage is caused by feeding and more seriously by transmitting viruses. Those of the genus begomovirus (Geminiviridae) cause the most significant crop diseases and are transmitted by B. tabaci in a persistent circulative mode, a process which is largely unknown. To analyze the translocation and to identify critical determinants for transmission, two populations of B. tabaci MEAM1 were compared for transmitting Watermelon chlorotic stunt virus (WmCSV) and Tomato yellow leaf curl virus (TYLCV). Insect populations were chosen because of their high and respectively low virus transmission efficiency to compare uptake and translocation of virus through insects. Both populations harbored Rickettsia, Hamiltonella and Wolbachia in comparable ratios indicating that endosymbionts might not contribute to the different transmission rates. Quantification by qPCR revealed that WmCSV uptake and virus concentrations in midguts and primary salivary glands were generally higher than TYLCV due to higher virus contents of the source plants. Both viruses accumulated higher in insects from the efficiently compared to the poorly transmitting population. In the latter, virus translocation into the hemolymph was delayed and virus passage was impeded with limited numbers of viruses translocated. FISH analysis confirmed these results with similar virus distribution found in excised organs of both populations. No virus accumulation was found in the midgut lumen of the poor transmitter because of a restrained virus translocation. Results suggest that the poorly transmitting population comprised insects that lacked transmission competence. Those were selected to develop a population that lacks virus transmission. Investigations with insects lacking transmission showed that virus concentrations in midguts were reduced and only negligible virus amounts were found at the

  19. Development of silverleaf assay, protein and nucleic acid-based diagnostic techniques for the quick and reliable detection and monitoring of biotype B of the whitefly, Bemisia tabaci (Gennadius).

    PubMed

    Shankarappa, K S; Rangaswamy, K T; Aswatha Narayana, D S; Rekha, A R; Raghavendra, N; Lakshminarayana Reddy, C N; Chancellor, T C B; Maruthi, M N

    2007-10-01

    The aim of this study was to develop and optimize silverleaf bioassay, esterase analysis and PCR-based techniques to distinguish quickly and reliably biotype B of the whitefly, Bemisia tabaci (Gennadius), from Indian indigenous biotypes. Zucchini and squash readily develop silverleaf symptoms upon feeding by the B biotype, but they are not readily available in Indian markets. A local pumpkin variety 'Big' was, therefore, used in silverleaf assay, which developed symptoms similar to those on zucchini and squash and can be used reliably to detect B biotype. Analysis of non-specific esterases of B and the indigenous biotypes indicated both quantitative and qualitative differences in esterase patterns. Two high molecular weight bands were unique to B biotype and they occurred in abundance. These esterases were used to develop quick and field-based novel detection methods for differentiating B from the indigenous biotypes. Development of these simple and cost-effective protocols has wider application as they can be potentially used to identify other agricultural pests. Mitochondrial cytochrome oxidase I gene sequences and randomly amplified polymorphic DNA (RAPD) polymorphisms, generated using the primer OpB11, were also found useful for detecting B. tabaci biotypes. A B biotype-specific RAPD band of 800 bp was sequenced, which was used to a develop sequence characterized amplified region (SCAR) marker. The SCAR marker involved the development of B biotype-specific primers that amplified 550 bp PCR products only from B biotype genomic DNA. Silverleaf assay, esterases, RAPDs or a SCAR marker were used in combination to analyse whitefly samples collected from selected locations in India, and it was found that any of these techniques can be used singly or in combination to detect B biotype reliably. The B biotype was found in southern parts of India but not in the north in 2004-06.

  20. Insecticide resistance in Bemisia tabaci Gennadius (Homoptera: Aleyrodidae) and Anopheles gambiae Giles (Diptera: Culicidae) could compromise the sustainability of malaria vector control strategies in West Africa.

    PubMed

    Gnankiné, Olivier; Bassolé, Imael H N; Chandre, Fabrice; Glitho, Isabelle; Akogbeto, Martin; Dabiré, Roch K; Martin, Thibaud

    2013-10-01

    Insecticides from the organophosphate (OP) and pyrethroid (PY) chemical families, have respectively, been in use for 50 and 30 years in West Africa, mainly against agricultural pests, but also against vectors of human disease. The selection pressure, with practically the same molecules year after year (mainly on cotton), has caused insecticide resistance in pest populations such as Bemisia tabaci, vector of harmful phytoviruses on vegetables. The evolution toward insecticide resistance in malaria vectors such as Anopheles gambiae sensus lato (s.l.) is probably related to the current use of these insecticides in agriculture. Thus, successful pest and vector control in West Africa requires an investigation of insect susceptibility, in relation to the identification of species and sub species, such as molecular forms or biotypes. Identification of knock down resistance (kdr) and acetylcholinesterase gene (Ace1) mutations modifying insecticide targets in individual insects and measure of enzymes activity typically involved in insecticide metabolism (oxidase, esterase and glutathion-S-transferase) are indispensable in understanding the mechanisms of resistance. Insecticide resistance is a good example in which genotype-phenotype links have been made successfully. Insecticides used in agriculture continue to select new resistant populations of B. tabaci that could be from different biotype vectors of plant viruses. As well, the evolution of insecticide resistance in An. gambiae threatens the management of malaria vectors in West Africa. It raises the question of priority in the use of insecticides in health and/or agriculture, and more generally, the question of sustainability of crop protection and vector control strategies in the region. Here, we review the susceptibility tests, biochemical and molecular assays data for B. tabaci, a major pest in cotton and vegetable crops, and An. gambiae, main vector of malaria. The data reviewed was collected in Benin and Burkina

  1. MicroRNA profiling of the whitefly Bemisia tabaci Middle East-Aisa Minor I following the acquisition of Tomato yellow leaf curl China virus.

    PubMed

    Wang, Bi; Wang, Lanlan; Chen, Fangyuan; Yang, Xiuling; Ding, Ming; Zhang, Zhongkai; Liu, Shu-Sheng; Wang, Xiao-Wei; Zhou, Xueping

    2016-02-02

    The begomoviruses are the largest and most economically important group of plant viruses exclusively vectored by whitefly (Bemisia tabaci) in a circulative, persistent manner. During this process, begomoviruses and whitefly vectors have developed close relationships and complex interactions. However, the molecular mechanisms underlying these interactions remain largely unknown, and the microRNA profiles for viruliferous and nonviruliferous whiteflies have not been studied. Sequences of Argonaute 1(Ago1) and Dicer 1 (Dcr1) genes were cloned from B. tabaci MEAM1 cDNAs. Subsequently, deep sequencing of small RNA libraries from uninfected and Tomato yellow leaf curl China virus (TYLCCNV)-infected whiteflies was performed. The conserved and novel miRNAs were identified using the release of miRBase Version 19.0 and the prediction software miRDeep2, respectively. The sequencing results of selected deregulated and novel miRNAs were further confirmed using quantitative reverse transcription-PCR. Moreover, the previously published B. tabaci MEAM1 transcriptome database and the miRNA target prediction algorithm miRanda 3.1 were utilized to predict potential targets for miRNAs. Gene Ontology (GO) analysis was also used to classify the potential enriched functional groups of their putative targets. Ago1 and Dcr1orthologs with conserved domains were identified from B. tabaci MEAM1. BLASTn searches and sequence analysis identified 112 and 136 conserved miRNAs from nonviruliferous and viruliferous whitefly libraries respectively, and a comparison of the conserved miRNAs of viruliferous and nonviruliferous whiteflies revealed 15 up- and 9 down-regulated conserved miRNAs. 7 novel miRNA candidates with secondary pre-miRNA hairpin structures were also identified. Potential targets of conserved and novel miRNAs were predicted using GO analysis, for the targets of up- and down-regulated miRNAs, eight and nine GO terms were significantly enriched. We identified Ago1 and Dcr1 orthologs

  2. Genetic diversity of Bemisia tabaci species colonizing cassava in Central African Republic characterized by analysis of cytochrome c oxidase subunit I

    PubMed Central

    Tocko-Marabena, Brice Kette; Silla, Semballa; Simiand, Christophe; Zinga, Innocent; Legg, James; Reynaud, Bernard

    2017-01-01

    After 2007, upsurges of whiteflies on cassava plants and high incidences of cassava diseases were observed in Central African Republic. This recent upsurge in the abundance of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) was directly linked to serious damage to cassava crops resulting from spread of whitefly-borne cassava mosaic geminiviruses (CMGs). There is currently very little information describing whitefly populations on cassava and associated crops in Central African Republic. The current study aimed to address this gap, and to determine whether the increasing damage associated with B. tabaci whiteflies was the consequence of a new invasion, or an upsurge of a local population. The molecular genetic identification and phylogenetic relationships of 898 B. tabaci adult individuals collected from representative locations (54) throughout CAR were determined based on their mitochondrial cytochrome oxidase I sequences (mtCOI). Field and ecological data were also collected from each site, including whitefly abundance, CMD incidence, host plants colonized by B. tabaci and agro-ecological zone. Phylogenetic analysis of the whitefly mtCOI sequences indicated that SSA1 (-SG1, -SG2), SSA3, MED, MEAM1 and Indian Ocean (IO) putative species occur in CAR. One specific haplotype of SSA1-SG1 (SSA1-SG1-P18F5) predominated on most cassava plants and at the majority of sites. This haplotype was identical to the SSA1-SG1 Mukono8-4 (KM377961) haplotype that was recorded from Uganda but that also occurs widely in CMD pandemic-affected areas of East Africa. These results suggest that the SSA1-SG1-P18F5 haplotype occurring in CAR represents a recent invasive population, and that it is the likely cause of the increased spread and severity of CMD in CAR. Furthermore, the high mtDNA sequence diversity observed for SSA1 and its broad presence on all sites and host plants sampled suggest that this genetic group was the dominant resident species even before the arrival of this new

  3. Whitefly resistance traits derived from the wild tomato Solanum pimpinellifolium affect the preference and feeding behavior of Bemisia tabaci and reduce the spread of Tomato yellow leaf curl virus.

    PubMed

    Rodríguez-López, M J; Garzo, E; Bonani, J P; Fereres, A; Fernández-Muñoz, R; Moriones, E

    2011-10-01

    Breeding of tomato genotypes that limit whitefly (Bemisia tabaci) access and feeding might reduce the spread of Tomato yellow leaf curl virus (TYLCV), a begomovirus (genus Begomovirus, family Geminiviridae) that is the causal agent of tomato yellow leaf curl disease. TYLCV is restricted to the phloem and is transmitted in a persistent manner by B. tabaci. The tomato breeding line ABL 14-8 was developed by introgressing type IV leaf glandular trichomes and secretion of acylsucroses from the wild tomato Solanum pimpinellifolium accession TO-937 into the genetic background of the whitefly- and virus-susceptible tomato cultivar Moneymaker. Results of preference bioassays with ABL 14-8 versus Moneymaker indicated that presence of type IV glandular trichomes and the production of acylsucrose deterred the landing and settling of B. tabaci on ABL 14-8. Moreover, electrical penetration graph studies indicated that B. tabaci adults spent more time in nonprobing activities and showed a reduced ability to start probing. Such behavior resulted in a reduced ability to reach the phloem. The superficial type of resistance observed in ABL 14-8 against B. tabaci probing significantly reduced primary and secondary spread of TYLCV.

  4. Susceptibility of Bemisia tabaci MEAM1 (Hemiptera: Aleyrodidae) to imidacloprid, thiamethoxam, dinotefuran and flupyradifurone in south Florida

    USDA-ARS?s Scientific Manuscript database

    Populations of Bemisa tabaci Middle East Asia Minor 1 (MEAM 1) were established from nineteen locations in south Florida, primarily from commercial tomato fields, and were tested using a cotton leaf petiole systemic uptake method for susceptibility to the nicotinic acetylcholine agonist insecticides...

  5. Arabidopsis thaliana plants with different levels of aliphatic- and indolyl-glucosinolates affect host selection and performance of Bemisia tabaci.

    PubMed

    Markovich, Oshry; Kafle, Dinesh; Elbaz, Moshe; Malitsky, Sergey; Aharoni, Asaph; Schwarzkopf, Alexander; Gershenzon, Jonathan; Morin, Shai

    2013-12-01

    Generalist insects show reduced selectivity when subjected to similar, but not identical, host plant chemical signatures. Here, we produced transgenic Arabidopsis thaliana plants that over-express genes regulating the aliphatic- and indolyl- glucosinolates biosynthetic pathways with either a constitutive (CaMV 35S) or a phloem-specific promoter (AtSUC2). This allowed us to examine how exposure to high levels of aliphatic- or indolyl-glucosinolates in homogenous habitats (leaf cage apparatus containing two wild-type or two transgenic leaves) and heterogeneous habitats (leaf cage apparatus containing one wild-type and one transgenic leaf) affects host selection and performance of Bemsia tabaci, a generalist phloem-feeding insect. Data from homogenous habitats indicated that exposure to A. thaliana plants accumulating high levels of aliphatic- or indolyl-glucosinolates negatively affected the performance of both adult females and nymphs of B. tabaci. Data from heterogeneous habitats indicated that B. tabaci adult females selected for oviposition plants on which their offspring perform better (preference-performance relationship). However, the combinations of wild-type and transgenic plants in heterogeneous habitats increased the period of time until the first choice was made and led to increased movement rate on transgenic plants, and reduced fecundity on wild-type plants. Overall, our findings are consistent with the view that both performance and selectivity of B. tabaci decrease in heterogeneous habitats that contain plants with closely-related chemical signatures.

  6. Release and recovery of exotic parasitoids of Bemisia tabaci in the Lower Rio Grande Valley of Texas

    USDA-ARS?s Scientific Manuscript database

    An intensive field program was conducted in the subtropical Lower Rio Grande Valley of Texas (LRGV) to evaluate the establishment of the imported parasitoids of B. tabaci. Thirty populations/species of Eretmocerus and Encarsia parasitoids were mass reared for field release in multiple agricultural c...

  7. Effect of Three Bean Species on the Development and Reproduction of a Population of the Parasltold, Encarsia bimaculata, on the Whitefly, Bemisia tabaci

    PubMed Central

    Mansaray, Augustine; Sundufu, Abu James

    2010-01-01

    Developmental time, parasitism, emergence, longevity, fecundity and demographic parameters of population of Encarsia bimaculata Heraty and Polaszek (Hymenoptera: Aphelinidae), a parasitoid attacking Bemisia tabaci (biotype B) (Gennadius) (Homoptera: Aleyrodidae) infesting soybean, Glyine max L. (Merr), cowpea, Vigna unguiulata L. and garden bean, Phaseolus vulgaris L. (Fabeles: Fabaceae) were quantified and compared. Encarsia bimaculata was able to complete its life cycle independent of the B. tabaci instar parasitized. However, parasitoid development was significantly slower when first (19 d), second (15 d) instars or pharate adults (14 d) were parasitized compared to the third (13 d) or fourth (13 d) instars. Consequently, percent parasitism was higher when the third (51 %) or fourth (46 %) instars were parasitized compared to the first (22 %), second (25 %) instars or pharate adults (36 %) of B. tabaci. Similarly, percent parasitoid emergence was significantly higher when third (83 %) or fourth (76 %) instars were parasitized compared to when the first (34 %), second (64 %) or pharate adults (54 %) were parasitized. Host plant species significantly influenced egg to adult developmental time, percent parasitism and the day on which E. bimaculata nymphs hatching from eggs was first observed. More nymphs were parasitized on cowpea (40 %) followed by garden bean (36 %) and soybean (32 %), while percent hatching was significantly higher on soybean (76 %) followed by cowpea (68 %) and garden bean (42 %). Adult parasitoid females lived an average of 6.7 d on soybean, 7.6 d on cowpea and 7.2 d on garden bean and laid a lifetime average of 27 eggs on soybean, 31 eggs on cowpea and 30 eggs on garden bean. The daily mean fecundity of E. bimaculata was not significantly different on the three bean species. Life table parameters showed that the net reproductive rate (Ro) was 14.50, generation time (Tc) was 17.16, intrinsic rate of natural increase (rm) was 0.16, finite rate

  8. Development of a lateral flow test to detect metabolic resistance in Bemisia tabaci mediated by CYP6CM1, a cytochrome P450 with broad spectrum catalytic efficiency.

    PubMed

    Nauen, Ralf; Wölfel, Katharina; Lueke, Bettina; Myridakis, Antonis; Tsakireli, Dimitra; Roditakis, Emmanouil; Tsagkarakou, Anastasia; Stephanou, Euripides; Vontas, John

    2015-06-01

    Cotton whitefly, Bemisia tabaci (Genn.) (Homoptera: Aleyrodidae) is a major sucking pest in many agricultural and horticultural cropping systems globally. The frequent use of insecticides of different mode of action classes resulted in populations resisting treatments used to keep numbers under economic damage thresholds. Recently it was shown that resistance to neonicotinoids such as imidacloprid is linked to the over-expression of CYP6CM1, a cytochrome P450 monooxygenase detoxifying imidacloprid and other neonicotinoid insecticides when recombinantly expressed in insect cells. However over-expression of CYP6CM1 is also known to confer cross-resistance to pymetrozine, an insecticide not belonging to the chemical class of neonicotinoids. In addition we were able to demonstrate by LC-MS/MS analysis the metabolisation of pyriproxyfen by recombinantly expressed CYP6CM1. Based on our results CYP6CM1 is one of the most versatile detoxification enzymes yet identified in a pest of agricultural importance, as it detoxifies a diverse range of chemical classes used to control whiteflies. Therefore we developed a field-diagnostic antibody-based lateral flow assay which detects CYP6CM1 protein at levels providing resistance to neonicotinoids and other insecticides. The ELISA based test kit can be used as a diagnostic tool to support resistance management strategies based on the alternation of different modes of action of insecticides. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. The ability to manipulate plant glucosinolates and nutrients explains the better performance of Bemisia tabaci Middle East-Asia Minor 1 than Mediterranean on cabbage plants.

    PubMed

    Cui, Hongying; Guo, Litao; Wang, Shaoli; Xie, Wen; Jiao, Xiaoguo; Wu, Qingjun; Zhang, Youjun

    2017-08-01

    The performance of herbivorous insects is greatly affected by host chemical defenses and nutritional quality. Some herbivores have developed the ability to manipulate plant defenses via signaling pathways. It is currently unclear, however, whether a herbivore can benefit by simultaneously reducing plant defenses and enhancing plant nutritional quality. Here, we show that the better performance of the whitefly Bemisia tabaci Middle East-Asia Minor 1 (MEAM1; formerly the "B" biotype) than Mediterranean (MED; formerly the "Q" biotype) on cabbage is associated with a suppression of glucosinolate (GS) content and an increase in amino acid supply in MEAM1-infested cabbage compared with MED-infested cabbage. MEAM1 had higher survival, higher fecundity, higher intrinsic rate of increase (rm), a longer life span, and a shorter developmental time than MED on cabbage plants. Amino acid content was higher in cabbage infested with MEAM1 than MED. Although infestation by either biotype decreased the levels of total GS, aliphatic GS, glucoiberin, sinigrin, glucobrassicin, and 4OH-glucobrassicin, and the expression of related genes in cabbage, MED infestation increased the levels of 4ME-glucobrassicin, neoglucobrassicin, progoitrin, and glucoraphanin. The GS content and expression of GS-related genes were higher in cabbage infested with MED than with MEAM1. Our results suggest that MEAM1 performs better than MED on cabbage by manipulating host defenses and nutritional quality.

  10. Resistance mechanisms to chlorpyrifos and F392W mutation frequencies in the acetylcholine esterase ace1 allele of field populations of the tobacco whitefly, Bemisia tabaci in China.

    PubMed

    Zhang, Ning-ning; Liu, Cai-feng; Yang, Fang; Dong, Shuang-lin; Han, Zhao-jun

    2012-01-01

    The tobacco whitefly B-biotype Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) is a worldwide pest of many crops. In China, chlorpyrifos has been used to control this insect for many years and is still being used despite the fact that some resistance has been reported. To combat resistance and maintain good control efficiency of chlorpyrifos, it is essential to understand resistance mechanisms. A chlorpyrifos resistant tobacco whitefly strain (NJ-R) and a susceptible strain (NJ-S) were derived from a field-collected population in Nanjing, China, and the resistance mechanisms were investigated. More than 30-fold resistance was achieved after selected by chlorpyrifos for 13 generations in the laboratory. However, the resistance dropped significantly to about 18-fold in only 4 generations without selection pressure. Biochemical assays indicated that increased esterase activity was responsible for this resistance, while acetylcholine esterase, glutathione S-transferase, and microsomal-O-demethylase played little or no role. F392W mutations in acel were prevalent in NJ-S and NJ-R strains and 6 field-collected populations of both B and Q-biotype from locations that cover a wide geographical area of China. These findings provide important information about tobacco whitefly chlorpyrifos resistance mechanisms and guidance to combat resistance and optimize use patterns of chlorpyrifos and other organophosphate and carbamate insecticides.

  11. Molecular characterization and oxidative stress response of an intracellular Cu/Zn superoxide dismutase (CuZnSOD) of the whitefly, Bemisia tabaci.

    PubMed

    Li, Jun-Min; Su, Yun-Lin; Gao, Xian-Long; He, Jiao; Liu, Shu-Sheng; Wang, Xiao-Wei

    2011-07-01

    Superoxide dismutases (SODs) are important for the survival of insects under environmental and biological stresses; however, little attention has been devoted to the functional characterization of SODs in whitefly. In this study, an intracellular copper/zinc superoxide dismutase of whitefly (Bemisia tabaci) (Bt-CuZnSOD) was cloned. Sequence analysis indicated that the full length cDNA of Bt-CuZnSOD is of 907 bp with a 471 bp open reading frame encoding 157 amino acids. The deduced amino acid sequence shares common consensus patterns with the CuZnSODs of various vertebrate and invertebrate animals. Phylogenetic analysis revealed that Bt-CuZnSOD is grouped together with intracellular CuZnSODs. Bt-CuZnSOD was then over-expressed in E. coli and purified using GST purification system. The enzymatic activity of purified Bt-CuZnSOD was assayed under various temperatures. When whiteflies were exposed to low (4°C) and high (40°C) temperatures, the in vivo activity of Bt-CuZnSOD was significantly increased. Furthermore, we measured the activities of several antioxidant enzymes, including SOD, catalase and peroxidase, in the whitefly after transferring the whitefly from cotton to tobacco (an unfavorable host plant). We found that the activity of SOD increased rapidly on tobacco plant. Taken together, these results suggest that the Bt-CuZnSOD plays a major role in protecting the whitefly against various stress conditions. © 2011 Wiley-Liss, Inc.

  12. Viral infection of tobacco plants improves performance of Bemisia tabaci but more so for an invasive than for an indigenous biotype of the whitefly*

    PubMed Central

    Liu, Jian; Li, Meng; Li, Jun-min; Huang, Chang-jun; Zhou, Xue-ping; Xu, Fang-cheng; Liu, Shu-sheng

    2010-01-01

    The ecological effects of plant-virus-vector interactions on invasion of alien plant viral vectors have been rarely investigated. We examined the transmission of Tomato yellow leaf curl China virus (TYLCCNV) by the invasive Q biotype and the indigenous ZHJ2 biotype of the whitefly Bemisia tabaci, a plant viral vector, as well as the influence of TYLCCNV-infection of plants on the performance of the two whitefly biotypes. Both whitefly biotypes were able to acquire viruses from infected plants and retained them in their bodies, but were unable to transmit them to either tobacco or tomato plants. However, when the Q biotype fed on tobacco plants infected with TYLCCNV, its fecundity and longevity were increased by 7- and 1-fold, respectively, compared to those of the Q biotype fed on uninfected tobacco plants. When the ZHJ2 biotype fed on virus-infected plants, its fecundity and longevity were increased by only 2- and 0.5-fold, respectively. These data show that the Q biotype acquired higher beneficial effects from TYLCCNV-infection of tobacco plants than the ZHJ2 biotype. Thus, the Q biotype whitefly may have advantages in its invasion and displacement of the indigenous ZHJ2 biotype. PMID:20043350

  13. Insecticidal activity against Bemisia tabaci biotype B of peel essential oil of Citrus sinensis var. pear and Citrus aurantium cultivated in northeast Brazil.

    PubMed

    Ribeiro, Nicolle de Carvalho; da Camara, Claudio Augusto Gomes; Born, Flávia de Souza; de Siqueira, Herbert Alvaro Abreu

    2010-11-01

    The fumigant action of peel essential oils of Citrus sinensis var. pear (pear orange = PO) and C. aurantium (bitter orange = BO) from the northeast of Brazil were evaluated against Bemisia tabaci biotype B and compared with eugenol as a positive control. The oil concentration in the PO at 8.5 microL/L of air caused 97% mortality, while the oil concentration of BO at 9.5 microL/L of air caused 99% mortality. However, the LC50 estimates for both oils (LC50 = 3.80 microL/L of air for PO and LC50 = 5.80 microL/L of air for BO) did not differ from each other, but they did when compared with eugenol (LC50 = 0.20 microL/L of air). Regarding their effects on oviposition, the Citrus oils showed concentration-response dependence, reducing the number of eggs as the concentration increased, which was not observed for eugenol. The minimum concentrations of the oils that caused a significant reduction in the egg lay were 3.5 and 7.0 microL/L of air for BO and PO, respectively. These results suggest that oils from PO and BO peels may be promising as models to develop new insecticides that might be applied into the integrated management of whiteflies.

  14. Selection and validation of reference genes for qRT-PCR analysis during biological invasions: The thermal adaptability of Bemisia tabaci MED

    PubMed Central

    Lü, Zhi-Chuang; Liu, Wan-Xue; Wan, Fang-Hao

    2017-01-01

    The Bemisia tabaci Mediterranean (MED) cryptic species has been rapidly invading to most parts of the world owing to its strong ecological adaptability, which is considered as a model insect for stress tolerance studies under rapidly changing environments. Selection of a suitable reference gene for quantitative stress-responsive gene expression analysis based on qRT-PCR is critical for elaborating the molecular mechanisms of thermotolerance. To obtain accurate and reliable normalization data in MED, eight candidate reference genes (β-act, GAPDH, β-tub, EF1-α, GST, 18S, RPL13A and α-tub) were examined under various thermal stresses for varied time periods by using geNorm, NormFinder and BestKeeper algorithms, respectively. Our results revealed that β-tub and EF1-α were the best reference genes across all sample sets. On the other hand, 18S and GADPH showed the least stability for all the samples studied. β-act was proved to be highly stable only in case of short-term thermal stresses. To our knowledge this was the first comprehensive report on validation of reference genes under varying temperature stresses in MED. The study could expedite particular discovery of thermotolerance genes in MED. Further, the present results can form the basis of further research on suitable reference genes in this invasive insect and will facilitate transcript profiling in other invasive insects. PMID:28323834

  15. Cloning and Functional Characterization of c-Jun NH2-Terminal Kinase from the Mediterranean Species of the Whitefly Bemisia tabaci Complex

    PubMed Central

    Wang, Lan-Lan; Huang, Huang; Zhang, Chang-Rong; Xia, Jun; Liu, Shu-Sheng; Wang, Xiao-Wei

    2013-01-01

    c-Jun NH2-terminal kinase (JNK) signaling is a highly conserved pathway that controls gene transcription in response to a wide variety of biological and environmental stresses. In this study, a JNK from the invasive Mediterranean (MED) species of the whitefly Bemisia tabaci complex was cloned and characterized. The full-length JNK cDNA of MED consists of 1565 bp, with an 1176 bp open reading frame encoding 392 amino acids. Comparison of JNK amino acid sequences among different species showed that the sequences of JNKs are highly conserved. To reveal its biological function, the gene expression and functional activation of JNK were analyzed during various stress conditions. Quantitative RT-PCR analysis showed that the relative expression level of JNK remained hardly unchanged when the insects were transferred from cotton (a suitable host plant) to tobacco (an unsuitable host plant), infected with bacteria and treated with high and low temperatures. However, the mRNA level of JNK significantly increased when treated with fungal pathogens. Furthermore, we found that the amount of phosphorylated JNK increased significantly after fungal infection, while there is no obvious change for phosphorylated p38 and ERK. Our results indicate that the whitefly JNK plays an important role in whitefly’s immune responses to fungal infection. PMID:23807503

  16. Differential gene expression in whitefly Bemisia tabaci-infested tomato (Solanum lycopersicum) plants at progressing developmental stages of the insect's life cycle.

    PubMed

    Estrada-Hernández, María Gloria; Valenzuela-Soto, José Humberto; Ibarra-Laclette, Enrique; Délano-Frier, John Paul

    2009-09-01

    A suppression-subtractive-hybridization (SSH) strategy was used to identify genes whose expression was modified in response to virus-free whitefly Bemisia tabaci (Bt, biotype A) infestation in tomato (Solanum lycopersicum) plants. Thus, forward and reverse SSH gene libraries were generated at four points in the whitefly's life cycle, namely at (1) 2 days (adult feeding and oviposition: phase I); (2) 7 days (mobile crawler stage: phase II); (3) 12 days (second to third instar nymphal transition: phase III) and (4) 18 days (fourth instar nymphal stage: phase IV). The 169 genes with altered expression (up and downregulated) that were identified in the eight generated SSH libraries, together with 75 additional genes that were selected on the basis of their involvement in resistance responses against phytofagous insects and pathogens, were printed on a Nexterion(®) Slide MPX 16 to monitor their pattern of expression at the above phases. The results indicated that Bt infestation in tomato led to distinctive phase-specific expression/repression patterns of several genes associated predominantly with photosynthesis, senescence, secondary metabolism and (a)biotic stress. Most of the gene expression modifications were detected in phase III, coinciding with intense larval feeding, whereas fewer changes were detected in phases I and IV. These results complement previously reported gene expression profiles in Bt-infested tomato and Arabidopisis, and support and expand the opinion that Bt infestation leads to the downregulation of specific defense responses in addition to those controlled by jasmonic acid. Copyright © Physiologia Plantarum 2009.

  17. Selection and validation of reference genes for qRT-PCR analysis during biological invasions: The thermal adaptability of Bemisia tabaci MED.

    PubMed

    Dai, Tian-Mei; Lü, Zhi-Chuang; Liu, Wan-Xue; Wan, Fang-Hao

    2017-01-01

    The Bemisia tabaci Mediterranean (MED) cryptic species has been rapidly invading to most parts of the world owing to its strong ecological adaptability, which is considered as a model insect for stress tolerance studies under rapidly changing environments. Selection of a suitable reference gene for quantitative stress-responsive gene expression analysis based on qRT-PCR is critical for elaborating the molecular mechanisms of thermotolerance. To obtain accurate and reliable normalization data in MED, eight candidate reference genes (β-act, GAPDH, β-tub, EF1-α, GST, 18S, RPL13A and α-tub) were examined under various thermal stresses for varied time periods by using geNorm, NormFinder and BestKeeper algorithms, respectively. Our results revealed that β-tub and EF1-α were the best reference genes across all sample sets. On the other hand, 18S and GADPH showed the least stability for all the samples studied. β-act was proved to be highly stable only in case of short-term thermal stresses. To our knowledge this was the first comprehensive report on validation of reference genes under varying temperature stresses in MED. The study could expedite particular discovery of thermotolerance genes in MED. Further, the present results can form the basis of further research on suitable reference genes in this invasive insect and will facilitate transcript profiling in other invasive insects.

  18. Transcriptome analysis reveals a comprehensive insect resistance response mechanism in cotton to infestation by the phloem feeding insect Bemisia tabaci (whitefly).

    PubMed

    Li, Jianying; Zhu, Lizhen; Hull, J Joe; Liang, Sijia; Daniell, Henry; Jin, Shuangxia; Zhang, Xianlong

    2016-10-01

    The whitefly (Bemisia tabaci) causes tremendous damage to cotton production worldwide. However, very limited information is available about how plants perceive and defend themselves from this destructive pest. In this study, the transcriptomic differences between two cotton cultivars that exhibit either strong resistance (HR) or sensitivity (ZS) to whitefly were compared at different time points (0, 12, 24 and 48 h after infection) using RNA-Seq. Approximately one billion paired-end reads were obtained by Illumina sequencing technology. Gene ontology and KEGG pathway analysis indicated that the cotton transcriptional response to whitefly infestation involves genes encoding protein kinases, transcription factors, metabolite synthesis, and phytohormone signalling. Furthermore, a weighted gene co-expression network constructed from RNA-Seq datasets showed that WRKY40 and copper transport protein are hub genes that may regulate cotton defenses to whitefly infestation. Silencing GhMPK3 by virus-induced gene silencing (VIGS) resulted in suppression of the MPK-WRKY-JA and ET pathways and lead to enhanced whitefly susceptibility, suggesting that the candidate insect resistant genes identified in this RNA-Seq analysis are credible and offer significant utility. Taken together, this study provides comprehensive insights into the cotton defense system to whitefly infestation and has identified several candidate genes for control of phloem-feeding pests.

  19. Increased survival and prolonged longevity mainly contribute to the temperature-adaptive evolutionary strategy in invasive Bemisia tabaci (Hemiptera: Aleyrodidae) Middle East Asia Minor 1.

    PubMed

    Lü, Zhi-Chuang; Gao, Qing-Lei; Wan, Fang-Hao; Yu, Hao; Guo, Jian-Ying

    2014-10-15

    With increasing global climate change, analyses of stress-inducing conditions have important significance in ecological adaptation and the biological distribution of species. To reveal the difference in temperature-adaptive strategy between Turpan and Beijing populations of Bemisia tabaci (Gennadius) Middle East Asia Minor 1 (MEAM1) under high-temperature stress conditions, we compared thermal tolerance and life history traits between Beijing and Turpan populations of MEAM1 after exposure to different heat shock treatments for different times. The experimental design reflected the nature of heat stress conditions suffered by MEAM1. The results showed that eggs, red-eyed pupae, and adults of the Turpan population were more heat tolerant than those of the Beijing population under the same stress conditions. Additionally, it was found that longevity and F1 adult survival rate were significantly higher in the Turpan population than in the Beijing population after heat shock stress, but egg number and F1 female ratio were not significantly different between Turpan population and Beijing population. Overall, it was suggested that heat tolerance and longevity traits were the most relevant for climate characteristics and not reproductive traits, and improved heat tolerance and prolonged longevity were important adaptive strategies that helped MEAM1 to survive in harsh high-temperature conditions such as Turpan arid desert climate. The present results provided further insight into the modes of heat tolerance and the ways in which survival and longevity traits respond to environmental selection pressures.

  20. Resistance Mechanisms to Chlorpyrifos and F392W Mutation Frequencies in the Acetylcholine Esterase Ace1 Allele of Field Populations of the Tobacco Whitefly, Bemisia tabaci in China

    PubMed Central

    Zhang, Ning-ning; Liu, Cai-feng; Yang, Fang; Dong, Shuang-lin; Han, Zhao-jun

    2012-01-01

    The tobacco whitefly B-biotype Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) is a worldwide pest of many crops. In China, chlorpyrifos has been used to control this insect for many years and is still being used despite the fact that some resistance has been reported. To combat resistance and maintain good control efficiency of chlorpyrifos, it is essential to understand resistance mechanisms. A chlorpyrifos resistant tobacco whitefly strain (NJ-R) and a susceptible strain (NJ-S) were derived from a field-collected population in Nanjing, China, and the resistance mechanisms were investigated. More than 30-fold resistance was achieved after selected by chlorpyrifos for 13 generations in the laboratory. However, the resistance dropped significantly to about 18-fold in only 4 generations without selection pressure. Biochemical assays indicated that increased esterase activity was responsible for this resistance, while acetylcholine esterase, glutathione S-transferase, and microsomal-O-demethylase played little or no role. F392W mutations in acel were prevalent in NJ-S and NJ-R strains and 6 field-collected populations of both B and Q-biotype from locations that cover a wide geographical area of China. These findings provide important information about tobacco whitefly chlorpyrifos resistance mechanisms and guidance to combat resistance and optimize use patterns of chlorpyrifos and other organophosphate and carbamate insecticides. PMID:22954331

  1. Effectiveness of Cyantraniliprole for Managing Bemisia tabaci (Hemiptera: Aleyrodidae) and Interfering with Transmission of Tomato Yellow Leaf Curl Virus on Tomato.

    PubMed

    Caballero, Rafael; Schuster, David J; Peres, Natalia A; Mangandi, Jozer; Hasing, Tomas; Trexler, Fred; Kalb, Steve; Portillo, Héctor E; Marçon, Paula C; Annan, I B

    2015-06-01

    Cyantraniliprole is the second xylem-systemic active ingredient in the new anthranilic diamide class. Greenhouse (2006), growth chamber (2007), and field studies (2009-2010) were conducted to determine the efficacy of cyantraniliprole for managing Bemisia tabaci (Gennadius) biotype B and in interfering with transmission of tomato yellow leaf curl virus (TYLCV) by this whitefly. Cyantraniliprole applied as soil treatments (200 SC) or foliar sprays (100 OD) provided excellent adult whitefly control, TYLCV suppression, and reduced oviposition and nymph survival, comparable to current standards. The positive results observed in these greenhouse experiments with a high level of insect pressure (10× the field threshold of one adult per plant) and disease pressure (five adults per plant, with a high level of confidence that TYLCV virulent adults were used), indicate a great potential for cyantraniliprole to be used in a whitefly management program. Field evaluations of soil drench treatments confirmed the suppression of TYLCV transmission demonstrated in the greenhouse studies. Field studies in 2009 and 2010 showed that cyantraniliprole (200 SC) provided TYLCV suppression for 2 wk after a drench application, when using a susceptible (2009) or imidacloprid-tolerant (2010) whitefly population. Cyantraniliprole was demonstrated to be a promising tool for management of TYLCV in tomato production, which is very difficult and expensive, and which has limited options. The integration of cyantraniliprole into a resistance management program will help to ensure the continued sustainability of this and current insecticides used for the management of insect vectors, including whiteflies and the TYLCV they spreads. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. Evaluation of Bioinsecticides for Management of Bemisia tabaci (Hemiptera: Aleyrodidae) and the Effect on the Whitefly Predator Delphastus catalinae (Coleoptera: Coccinellidae) in Organic Squash.

    PubMed

    Razze, Janine M; Liburd, Oscar E; Nuessly, Gregg S; Samuel-Foo, Michelle

    2016-08-01

    Organic zucchini squash is a high-value vegetable crop in Florida and potential exists to expand its production throughout the state. A lack of knowledge on the effectiveness of organic products and their integration with natural enemies is an important constraint to the regulation of pest populations in organic squash production in Florida. The objectives of this study were to evaluate the effect of insecticides labeled for organic production that can be used for management of Bemisia tabaci (Gennadius) biotype B, on organically grown squash; and to determine the effects of the most efficient insecticides on a key natural enemy, Delphastus catalinae (Horn). Experiments were conducted in the greenhouse in exclusion cages. The first experiment compared the effects of four bioinsecticides on whitefly densities. Insecticides include 1) AzaSol (azadirachtin), 2) PyGanic EC 1.4 (pyrethrin), 3) M-Pede (insecticidal soap), and 4) Entrust (spinosad). The second experiment investigated the effects of bioinsecticides on D. catalinae Treatment effectiveness was evaluated 1, 3, and 5 d posttreatment. PyGanic and M-Pede were highly effective in controlling whitefly populations on organic squash, while moderate control was provided by AzaSol and there was no control provided by Entrust. PyGanic and M-Pede treatments reduced D. catalinae populations when adults were released 1 d post pesticide application. However, when adults were released 5 d post application, there was no reduction. The importance of using bioinsecticides in combination with natural enemies to regulate pest populations in organic cropping systems is discussed.

  3. Susceptibility of Bemisia tabaci MEAM1 (Hemiptera: Aleyrodidae) to Imidacloprid, Thiamethoxam, Dinotefuran and Flupyradifurone in South Florida.

    PubMed

    Smith, Hugh A; Nagle, Curtis A; MacVean, Charles A; McKenzie, Cindy L

    2016-10-20

    Populations of Bemisa tabaci MEAM1 were established from nineteen locations in south Florida, primarily from commercial tomato fields, and were tested using a cotton leaf petiole systemic uptake method for susceptibility to the nicotinic acetylcholine agonist insecticides imidacloprid, thiamethoxam, dinotefuran and flupyradifurone. Eleven populations produced LC50s for one or more chemicals that were not significantly different from the susceptible laboratory colony based on overlapping fiducial limits, indicating some degree of susceptibility. LC50s more than a 100-fold the laboratory colony were measured in at least one population for each material tested, indicating tolerance. LC50s (ppm) from field populations ranged from 0.901-24.952 for imidacloprid, 0.965-24.430 for thiamethoxam, 0.043-3.350 for dinotefuran and 0.011-1.471 for flupyradifurone. Based on overlapping fiducial limits, there were no significant differences in relative mean potency estimates for flupyradifurone and dinotefuran in relation to imidacloprid and thiamethoxam.

  4. Effectiveness of two insect growth regulators against Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) and Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) and their impact on population densities of arthropod predators in cotton in Pakistan.

    PubMed

    Gogi, Muhammad D; Sarfraz, Rana M; Dosdall, Lloyd M; Arif, Muhammad J; Keddie, Andrew B; Ashfaq, Muhammad

    2006-10-01

    Field efficacies of two insect growth regulators (IGRs) at two recommended application rates, buprofezin at 370 and 555 g AI ha(-1) and lufenuron at 37 and 49 g AI ha(-1), were determined against the sweet potato whitefly, Bemisia tabaci (Gennadius), and the cotton bollworm, Helicoverpa armigera (Hübner), in experimental plots of cotton at the Directorate of Cotton Research, Faisalabad, Pakistan. Adverse effects of the IGRs on populations of associated arthropod predators, namely geocorids, chrysopids, coccinellids, formicids and arachnids, were also assessed. Both IGRs significantly reduced populations of B. tabaci at each application rate 24, 48 and 72 h after treatment, and higher doses were more effective than lower doses. Buprofezin was not effective against H. armigera at any tested dose for any time of treatment in any spray. Lufenuron applied at 37 and 49 g AI ha(-1) effectively suppressed H. armigera populations, resulting in significant reductions in crop damage. At lower doses, both IGRs appeared safe to predator populations, which did not differ significantly in IGR-treated versus untreated control plots. Population densities of formicids and coccinellids were significantly lower at high concentrations of both IGRs in treatment plots, possibly as a result of reduced prey availability. The potential role of buprofezin and lufenuron for control of B. tabaci and H. armigera in a spray programme and the likelihood of direct toxic effects of IGRs on predatory fauna of cotton are discussed.

  5. Susceptibility of Bemisia tabaci MEAM1 (Hemiptera: Aleyrodidae) to Imidacloprid, Thiamethoxam, Dinotefuran and Flupyradifurone in South Florida

    PubMed Central

    Smith, Hugh A.; Nagle, Curtis A.; MacVean, Charles A.; McKenzie, Cindy L.

    2016-01-01

    Populations of Bemisa tabaci MEAM1 were established from nineteen locations in south Florida, primarily from commercial tomato fields, and were tested using a cotton leaf petiole systemic uptake method for susceptibility to the nicotinic acetylcholine agonist insecticides imidacloprid, thiamethoxam, dinotefuran and flupyradifurone. Eleven populations produced LC50s for one or more chemicals that were not significantly different from the susceptible laboratory colony based on overlapping fiducial limits, indicating some degree of susceptibility. LC50s more than a 100-fold the laboratory colony were measured in at least one population for each material tested, indicating tolerance. LC50s (ppm) from field populations ranged from 0.901–24.952 for imidacloprid, 0.965–24.430 for thiamethoxam, 0.043–3.350 for dinotefuran and 0.011–1.471 for flupyradifurone. Based on overlapping fiducial limits, there were no significant differences in relative mean potency estimates for flupyradifurone and dinotefuran in relation to imidacloprid and thiamethoxam. PMID:27775597

  6. Biological activity of natural phytoecdysteroids from Ajuga iva against the sweetpotato whitefly Bemisia tabaci and the persea mite Oligonychus perseae.

    PubMed

    Aly, Radi; Ravid, Uzi; Abu-Nassar, Jackline; Botnick, Ilan; Lebedev, Galina; Gal, Shira; Ziadna, Hammam; Achdari, Guy; Smirov, Evgeny; Meir, Ayala; Ghanim, Murad

    2011-12-01

    Ecdysteroids are steroid hormones that control moulting and govern several changes during metamorphoses in arthropods. The discovery of the same molecules (phytoecdysteroids) in several plant species displayed a wide array of rather beneficial agricultural impact. Many representatives of the genus Ajuga plants contain phytoecdysteroids with a 5β-7-ene-6-one system exhibiting physiological activities in insects. By means of chromatographic (silica gel column, TLC) and LC-MS, two major ecdysteroids (20-hydroxyecdysone and cyasterone) have been isolated and identified from Israeli carpet bugle Ajuga iva (L.) Schreber (Lamiales: Lamiaceae) plants. Ajuga iva extract fractionated on the silica gel column yielded two fractions that showed high activity against the sweetpotato whitefly Bemisis tabaci and the persea mite Oligonychus perseae. A dose of 5 mg AI L(-1) of the purely identified A. iva ecdysterone significantly reduced fecundity, fertility and survival of these pests, while commercial 20-hydroxyecdysone at the same dose had lesser effects. The results demonstrate considerable efficacy of natural phytoecdysteroids against major agricultural pests, and suggests that these materials should be considered for potential development of friendly control agents. Copyright © 2011 Society of Chemical Industry.

  7. Effects of Three Insect Growth Regulators on Encarsia formosa (Hymenoptera: Aphelinidae), an Endoparasitoid of Bemisia tabaci (Hemiptera: Aleyrodidae).

    PubMed

    Wang, Q L; Liu, T-X

    2016-10-15

    Insect growth regulators (IGRs) disrupt the normal activity of the endocrine or hormone system of insects, affecting the development, reproduction, or metamorphosis of the target insects, and normally causing less detrimental effects to beneficial insects. The effects of three IGRs (pyriproxyfen, fenoxycarb, and buprofezin) on Encarsia formosa Gahan, an endoparasitoid of whiteflies, were determined using B. tabaci as a host. We assessed the effects of the IGRs on parasitoid's larval development, pupation, emergence, and contact effects of the dry residues on plant leaf and glass vial surface on adult mortality and parasitism. When the three IGRs were applied at larval stage, no or few larvae pupated in the pyriproxyfen treatments and the highest concentration of fenoxycarb, and a majority of larvae pupated in the buprofezin treatments; of those pupated, 62.3-88.1% became adults. When the IGRs were applied at the pupal stage, 2.3-17.5% developed to adults in the pyriproxyfen treatments, 59.7-89.0% in the fenoxycarb treatments, and 58.4-83.6% in the buprofezin treatments. The leaf residues of the IGRs had no appreciable effects on adults, whereas the residues on glass vial caused significantly lower adult survival than on plant leaves. The residues of pyriproxyfen and fenoxycarb slightly reduced parasitism as compared with buprofezin and controls. However, the rates of parasitoids that became adults were significantly lower, especially in the pyriproxyfen treatments. According to the standards of International Organization of Biological Control (IOBC), pyriproxyfen was harmful, while fenoxycarb and buprofezin were slightly or moderately harmful to larvae and harmless to E. formosa pupae.

  8. RNA Interference Based Approach to Down Regulate Osmoregulators of Whitefly (Bemisia tabaci): Potential Technology for the Control of Whitefly

    USDA-ARS?s Scientific Manuscript database

    Over the past decade RNA interference (RNAi) technology has emerged as a successful tool not only for functional genomics, but in planta expression of short interfering RNAs (siRNAs) could offer potential for insect pest management. Insects feeding exclusively on plant sap depend on osmotic pressure...

  9. Virion Stability Is Important for the Circulative Transmission of Tomato Yellow Leaf Curl Sardinia Virus by Bemisia tabaci, but Virion Access to Salivary Glands Does Not Guarantee Transmissibility▿ †

    PubMed Central

    Caciagli, Piero; Medina Piles, Vicente; Marian, Daniele; Vecchiati, Manuela; Masenga, Vera; Mason, Giovanna; Falcioni, Tania; Noris, Emanuela

    2009-01-01

    The capsid protein (CP) of the monopartite begomovirus Tomato yellow leaf curl Sardinia virus (TYLCSV), family Geminiviridae, is indispensable for plant infection and vector transmission. A region between amino acids 129 and 152 is critical for virion assembly and insect transmissibility. Two previously described mutants, one with a double Q129P Q134H mutation (PNHD) and another with a further D152E change (PNHE), were found nontransmissible (NT). Another NT mutant with a single N130D change (QDQD) was retrieved from a new mutational analysis. In this study, these three NT mutants and the wild-type (wt) virus were compared in their relationships with the whitefly vector Bemisia tabaci and the nonvector Trialeurodes vaporariorum. Retention kinetics of NT mutants were analyzed by quantitative dot blot hybridization in whiteflies fed on infected plants. The QDQD mutant, whose virions appeared nongeminate following purification, was hardly detectable in either whitefly species at any sampling time. The PNHD mutant was acquired and circulated in both whitefly species for up to 10 days, like the wt virus, while PNHE circulated in B. tabaci only. Using immunogold labeling, both PNHD and PNHE CPs were detected in B. tabaci salivary glands (SGs) like the wt virus, while no labeling was found in any whitefly tissue with the QDQD mutant. Significant inhibition of transmission of the wt virus was observed after prior feeding of the insects on plants infected with the PNHE mutant, but not on plants infected with the other mutants. Virion stability and ability to cross the SG barrier are necessary for TYLCSV transmission, but interactions with molecular components inside the SGs are also critical for transmissibility. PMID:19321611

  10. Fumigant toxicity of summer savory and lemon balm oil constituents and efficacy of spray formulations containing the oils to B- and neonicotinoid-resistant Q-biotypes of Bemisia tabaci (Homoptera: Aleyrodidae).

    PubMed

    Chae, Song-Hwa; Kim, Soon-Il; Yeon, Seong Hum; Perumalsamy, Haribalan; Ahn, Young-Joon

    2014-02-01

    An assessment was made of the fumigant toxicity of 36 constituents from lemon balm oil (LBO) and summer savory oil (SSO) and another additional nine previously identified compounds of the oils, as well as of the control efficacy of four experimental spray formulations containing individual oils (0.5 and 0.1% sprays) and spinosad 10% suspension concentrate (SC) to females from B- and neonicotinoid-resistant Q-biotypes of Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae). Based on 24-h LC50 values, Q-biotype females (0.20 microg/cm3) were 40 times less susceptible to dichlorvos than B-biotype females (0.005 microg/cm3). Thymol (LC50, 0.35 microg/cm3) and carvacrol (0.56 microg/cm3) were the most toxic compounds toward Q-biotype females, followed by (1S)-(-)-borneol, alpha-terpineol, nerol, linalool, and carvone (1.06-1.38 microg/cm3). The toxicity of these compounds was virtually identical toward both biotype females, indicating that the terpenoids and the insecticides (neonicotinoids and dichlorvos) do not share a common mode of action or elicit cross-resistance. The 0.5% spray of LBO, SSO, and spinosad 10% SC resulted in >90% mortality toward both biotype females. Global efforts to reduce the level of toxic synthetic insecticides in the agricultural environment justify further studies on LBO- and SSO-derived materials as potential contact-action fumigants for the control of B. tabaci populations.

  11. Making a friend from a foe: expressing a GroEL gene from the whitefly Bemisia tabaci in the phloem of tomato plants confers resistance to tomato yellow leaf curl virus.

    PubMed

    Akad, F; Eybishtz, A; Edelbaum, D; Gorovits, R; Dar-Issa, O; Iraki, N; Czosnek, H

    2007-01-01

    Some (perhaps all) plant viruses transmitted in a circulative manner by their insect vectors avoid destruction in the haemolymph by interacting with GroEL homologues, ensuring transmission. We have previously shown that the phloem-limited begomovirus tomato yellow leaf curl virus (TYLCV) interacts in vivo and in vitro with GroEL produced by the whitefly vector Bemisia tabaci. In this study, we have exploited this phenomenon to generate transgenic tomato plants expressing the whitefly GroEL in their phloem. We postulated that following inoculation, TYLCV particles will be trapped by GroEL in the plant phloem, thereby inhibiting virus replication and movement, thereby rendering the plants resistant. A whitefly GroEL gene was cloned in an Agrobacterium vector under the control of an Arabidopsis phloem-specific promoter, which was used to transform two tomato genotypes. During three consecutive generations, plants expressing GroEL exhibited mild or no disease symptoms upon whitefly-mediated inoculation of TYLCV. In vitro assays indicated that the sap of resistant plants contained GroEL-TYLCV complexes. Infected resistant plants served as virus source for whitefly-mediated transmission as effectively as infected non-transgenic tomato. Non-transgenic susceptible tomato plants grafted on resistant GroEL-transgenic scions remained susceptible, although GroEL translocated into the grafted plant and GroEL-TYLCV complexes were detected in the grafted tissues.

  12. Inundative Field Releases and Evaluation of Three Predators for Bemisia tabasi (Hemiptera: Aleyrodidae) Management in Three Vegetable Crops

    USDA-ARS?s Scientific Manuscript database

    The sweetpotato whitefly, Bemisia tabaci (Gennadius), is a global pest on numerous crops, including vegetables. Weekly inundative releases of a coccinellid predator (Coccinella undecimpunctata L.), a mirid predator [Macrophillus caliginosus (Wagner)] and a neuropteran predator [Chrysoperla carnea S...

  13. Effect of foliar application of Xxpire on Bemisisa tabaci (MED whitefly) and Amblyseius swirskii, 2016

    USDA-ARS?s Scientific Manuscript database

    Bemisia tabaci is a polyphagous pest known to feed upon over 900 plant taxa, and is an effective vector of more than 100 plant damaging viruses. Among different biotypes of this cryptic species complex, MEAM1 and MED whitefly are the two most destructive members posing threats of several crops of ec...

  14. Transcription analysis of neonicotinoid resistance in Mediterranean (MED) populations of B. tabaci reveal novel cytochrome P450s, but no nAChR mutations associated with the phenotype.

    PubMed

    Ilias, Aris; Lagnel, Jacques; Kapantaidaki, Despoina E; Roditakis, Emmanouil; Tsigenopoulos, Costas S; Vontas, John; Tsagkarakou, Anastasia

    2015-11-14

    Bemisia tabaci is one of the most damaging agricultural pests world-wide. Although its control is based on insecticides, B. tabaci has developed resistance against almost all classes of insecticides, including neonicotinoids. We employed an RNA-seq approach to generate genome wide expression data and identify genes associated with neonicotinoid resistance in Mediterranean (MED) B. tabaci (Q1 biotype). Twelve libraries from insecticide resistant and susceptible whitefly populations were sequenced on an Illumina Next-generation sequencing platform, and genomic sequence information of approximately 73 Gbp was generated. A reference transcriptome was built by de novo assembly and functionally annotated. A total of 146 P450s, 18 GSTs and 23 CCEs enzymes (unigenes) potentially involved in the detoxification of xenobiotics were identified, along with 78 contigs encoding putative target proteins of six different insecticide classes. Ten unigenes encoding nicotinic Acetylcholine Receptors (nAChR), the target of neoinicotinoids, were identified and phylogenetically classified. No nAChR polymorphism potentially related with the resistant phenotypes, was observed among the studied strains. DE analysis revealed that among the 550 differentially (logFC > 1) over-transcribed unigenes, 52 detoxification enzymes were over expressed including unigenes with orthologues in P450s, GSTs, CCE and UDP-glucuronosyltransferases. Eight P450 unigenes belonging to clades CYP2, CYP3 and CYP4 were highly up-regulated (logFC > 2) including CYP6CM1, a gene already known to confer imidacloprid resistance in B. tabaci. Using quantitative qPCRs, a larger screening of field MED B. tabaci from Crete with known neonicotinoid phenotype was performed to associate expression levels of P450s with resistance levels. Expression levels of five P450s, including CYP6CM1, were found associated with neonicotinoid resistance. However, a significant correlation was found only in CYP303 and CYP6CX3, with imidacloprid

  15. A draft genome sequence and functional screen reveals the repertoire of type III secreted proteins of Pseudomonas syringae pathovar tabaci 11528

    PubMed Central

    Studholme, David J; Ibanez, Selena Gimenez; MacLean, Daniel; Dangl, Jeffery L; Chang, Jeff H; Rathjen, John P

    2009-01-01

    Background Pseudomonas syringae is a widespread bacterial pathogen that causes disease on a broad range of economically important plant species. Pathogenicity of P. syringae strains is dependent on the type III secretion system, which secretes a suite of up to about thirty virulence 'effector' proteins into the host cytoplasm where they subvert the eukaryotic cell physiology and disrupt host defences. P. syringae pathovar tabaci naturally causes disease on wild tobacco, the model member of the Solanaceae, a family that includes many crop species as well as on soybean. Results We used the 'next-generation' Illumina sequencing platform and the Velvet short-read assembly program to generate a 145X deep 6,077,921 nucleotide draft genome sequence for P. syringae pathovar tabaci strain 11528. From our draft assembly, we predicted 5,300 potential genes encoding proteins of at least 100 amino acids long, of which 303 (5.72%) had no significant sequence similarity to those encoded by the three previously fully sequenced P. syringae genomes. Of the core set of Hrp Outer Proteins that are conserved in three previously fully sequenced P. syringae strains, most were also conserved in strain 11528, including AvrE1, HopAH2, HopAJ2, HopAK1, HopAN1, HopI, HopJ1, HopX1, HrpK1 and HrpW1. However, the hrpZ1 gene is partially deleted and hopAF1 is completely absent in 11528. The draft genome of strain 11528 also encodes close homologues of HopO1, HopT1, HopAH1, HopR1, HopV1, HopAG1, HopAS1, HopAE1, HopAR1, HopF1, and HopW1 and a degenerate HopM1'. Using a functional screen, we confirmed that hopO1, hopT1, hopAH1, hopM1', hopAE1, hopAR1, and hopAI1' are part of the virulence-associated HrpL regulon, though the hopAI1' and hopM1' sequences were degenerate with premature stop codons. We also discovered two additional HrpL-regulated effector candidates and an HrpL-regulated distant homologue of avrPto1. Conclusion The draft genome sequence facilitates the continued development of P

  16. Biology and management of Bemisia whitefly vectors of cassava virus pandemics in Africa.

    PubMed

    Legg, James P; Shirima, Rudolph; Tajebe, Lensa S; Guastella, Devid; Boniface, Simon; Jeremiah, Simon; Nsami, Elibariki; Chikoti, Patrick; Rapisarda, Carmelo

    2014-10-01

    Cassava mosaic disease and cassava brown streak disease are caused by viruses transmitted by Bemisia tabaci and affect approximately half of all cassava plants in Africa, resulting in annual production losses of more than $US 1 billion. A historical and current bias towards virus rather than vector control means that these diseases continue to spread, and high Bemisia populations threaten future virus spread even if the extant strains and species are controlled. Progress has been made in parts of Africa in replicating some of the successes of integrated Bemisia control programmes in the south-western United States. However, these management efforts, which utilise chemical insecticides that conserve the Bemisia natural enemy fauna, are only suitable for commercial agriculture, which presently excludes most cassava cultivation in Africa. Initiatives to strengthen the control of B. tabaci on cassava in Africa need to be aware of this limitation, and to focus primarily on control methods that are cheap, effective, sustainable and readily disseminated, such as host-plant resistance and biological control. A framework based on the application of force multipliers is proposed as a means of prioritising elements of future Bemisia control strategies for cassava in Africa. © 2014 Society of Chemical Industry.

  17. Herbivory by Thrips tabaci

    Treesearch

    Deborah M. Kendall

    1991-01-01

    Herbivory by Thrips tabaci (Lindeman) affects both the bulb yield and phytohormone balance in its major host plant, the onion (Alium cepa L.). Seasonal changes in the susceptibility of onion yield to T. tabaci feeding were examined during the three growth stages of onion; prebulbing, bulbing and sizing (Kendall...

  18. Genetic analysis of Bemisia (Hemiptera: Aleyrodidae) populations by isoelectric focusing electrophoresis.

    PubMed

    Brown, J K; Perring, T M; Cooper, A D; Bedford, I D; Markham, P G

    2000-02-01

    Twenty-one whitefly populations in the genus Bemisia were evaluated for genetic variation at 3 allozyme loci. Nine of the 22 populations that exhibited polymorphic loci were subjected to allozyme analysis using a minimum of 10 enzymes, representing 10 to 14 distinct loci. Among those nine variants examined, calculated genetic distances ranged between 0.03 and 0.52, with three main groups emerging from the analysis. One group comprised two closely related Western Hemisphere variants of B. tabaci: type A from California, United States and a geographically proximal population from Culiacan, Mexico. A second cluster contained five collections previously identified as B. tabaci type B and Bemisia argentifolii, while a third group contained a single population from Benin, Africa. The latter two groups were grouped separately from New World populations and are thought to have a recent origin in the Eastern Hemisphere.

  19. Remote sensing for detecting and mapping whitefly (Bemisia tabaci) infestations

    USDA-ARS?s Scientific Manuscript database

    Remote sensing technology has long been used for detecting insect infestations on agricultural crops. With recent advances in remote sensing sensors and other spatial information technologies such as Global Position Systems (GPS) and Geographic Information Systems (GIS), remote sensing is finding mo...

  20. siRNA machinery in whitefly (Bemisia tabaci).

    PubMed

    Upadhyay, Santosh Kumar; Dixit, Sameer; Sharma, Shailesh; Singh, Harpal; Kumar, Jitesh; Verma, Praveen C; Chandrashekar, K

    2013-01-01

    RNA interference has been emerged as an utmost tool for the control of sap sucking insect pests. Systemic response is necessary to control them in field condition. Whitefly is observed to be more prone to siRNA in recent studies, however the siRNA machinery and mechanism is not well established. To identify the core siRNA machinery, we curated transcriptome data of whitefly from NCBI database. Partial mRNA sequences encoding Dicer2, R2D2, Argonaute2 and Sid1 were identified by tblastn search of homologous sequences from Aphis glycines and Tribolium castaneum. Complete encoding sequences were obtained by RACE, protein sequences derived by Expasy translate tool and confirmed by blastp analysis. Conserved domain search and Prosite-Scan showed similar domain architecture as reported in homologs from related insects. We found helicase, PAZ, RNaseIIIa, RNaseIIIb and double-stranded RNA-binding fold (DSRBF) in Dicer2; DsRBD in R2D2; and PAZ and PIWI domains in Argonaute2. Eleven transmembrane domains were detected in Sid1. Sequence homology and phylogenetic analysis revealed that RNAi machinery of whitefly is close to Aphids. Real-time PCR analysis showed similar expression of these genes in different developmental stages as reported in A. glycines and T. castaneum. Further, the expression level of above genes was quite similar to the housekeeping gene actin. Availability of core siRNA machinery including the Sid1 and their universal expression in reasonable quantity indicated significant response of whitefly towards siRNA. Present report opens the way for controlling whitefly, one of the most destructive crop insect pest.

  1. Transmission of Sweet Potato Leaf Curl Virus by Bemisia tabaci

    USDA-ARS?s Scientific Manuscript database

    Sweetpotato, Ipomoea batatas (L.) Lam. (Solanales: Convolvulaceae), is an important world food crop, and Asia is the focal production region. Because it is vegetatively propagated, sweetpotato is especially prone to accumulate infections by several viruses. Sweet potato leaf curl virus (SPLCV) (ss...

  2. siRNA Machinery in Whitefly (Bemisia tabaci)

    PubMed Central

    Upadhyay, Santosh Kumar; Dixit, Sameer; Sharma, Shailesh; Singh, Harpal; Kumar, Jitesh; Verma, Praveen C.; Chandrashekar, K.

    2013-01-01

    Background RNA interference has been emerged as an utmost tool for the control of sap sucking insect pests. Systemic response is necessary to control them in field condition. Whitefly is observed to be more prone to siRNA in recent studies, however the siRNA machinery and mechanism is not well established. Methodology/Principal Findings To identify the core siRNA machinery, we curated transcriptome data of whitefly from NCBI database. Partial mRNA sequences encoding Dicer2, R2D2, Argonaute2 and Sid1 were identified by tblastn search of homologous sequences from Aphis glycines and Tribolium castaneum. Complete encoding sequences were obtained by RACE, protein sequences derived by Expasy translate tool and confirmed by blastp analysis. Conserved domain search and Prosite-Scan showed similar domain architecture as reported in homologs from related insects. We found helicase, PAZ, RNaseIIIa, RNaseIIIb and double-stranded RNA-binding fold (DSRBF) in Dicer2; DsRBD in R2D2; and PAZ and PIWI domains in Argonaute2. Eleven transmembrane domains were detected in Sid1. Sequence homology and phylogenetic analysis revealed that RNAi machinery of whitefly is close to Aphids. Real-time PCR analysis showed similar expression of these genes in different developmental stages as reported in A. glycines and T. castaneum. Further, the expression level of above genes was quite similar to the housekeeping gene actin. Conclusions/Significance Availability of core siRNA machinery including the Sid1 and their universal expression in reasonable quantity indicated significant response of whitefly towards siRNA. Present report opens the way for controlling whitefly, one of the most destructive crop insect pest. PMID:24391810

  3. Whitefly genome expression reveals host-symbiont interaction in amino acid biosynthesis.

    PubMed

    Upadhyay, Santosh Kumar; Sharma, Shailesh; Singh, Harpal; Dixit, Sameer; Kumar, Jitesh; Verma, Praveen C; Chandrashekar, K

    2015-01-01

    Whitefly (Bemisia tabaci) complex is a serious insect pest of several crop plants worldwide. It comprises several morphologically indistinguishable species, however very little is known about their genetic divergence and biosynthetic pathways. In the present study, we performed transcriptome sequencing of Asia 1 species of B. tabaci complex and analyzed the interaction of host-symbiont genes in amino acid biosynthetic pathways. We obtained about 83 million reads using Illumina sequencing that assembled into 72716 unitigs. A total of 21129 unitigs were annotated at stringent parameters. Annotated unitigs were mapped to 52847 gene ontology (GO) terms and 131 Kyoto encyclopedia of genes and genomes (KEGG) pathways. Expression analysis of the genes involved in amino acid biosynthesis pathways revealed the complementation between whitefly and its symbiont partner Candidatus Portiera aleyrodidarum. Most of the non-essential amino acids and intermediates of essential amino acid pathways were supplied by the host insect to its symbiont. The symbiont expressed the pathways for the essential amino acids arginine, threonine and tryptophan and the immediate precursors of valine, leucine, isoleucine and phenyl-alanine. High level expression of the amino acid transporters in the whitefly suggested the molecular mechanisms for the exchange of amino acids between the host and the symbiont. Our study provides a comprehensive transcriptome data for Asia 1 species of B. tabaci complex that focusses light on integration of host and symbiont genes in amino acid biosynthesis pathways.

  4. The Complete Mitochondrial Genome of Aleurocanthus camelliae: Insights into Gene Arrangement and Genome Organization within the Family Aleyrodidae.

    PubMed

    Chen, Shi-Chun; Wang, Xiao-Qing; Li, Pin-Wu; Hu, Xiang; Wang, Jin-Jun; Peng, Ping

    2016-11-07

    There are numerous gene rearrangements and transfer RNA gene absences existing in mitochondrial (mt) genomes of Aleyrodidae species. To understand how mt genomes evolved in the family Aleyrodidae, we have sequenced the complete mt genome of Aleurocanthus camelliae and comparatively analyzed all reported whitefly mt genomes. The mt genome of A. camelliae is 15,188 bp long, and consists of 13 protein-coding genes, two rRNA genes, 21 tRNA genes and a putative control region (GenBank: KU761949). The tRNA gene, trnI, has not been observed in this genome. The mt genome has a unique gene order and shares most gene boundaries with Tetraleurodes acaciae. Nineteen of 21 tRNA genes have the conventional cloverleaf shaped secondary structure and two (trnS₁ and trnS₂) lack the dihydrouridine (DHU) arm. Using ARWEN and homologous sequence alignment, we have identified five tRNA genes and revised the annotation for three whitefly mt genomes. This result suggests that most absent genes exist in the genomes and have not been identified, due to be lack of technology and inference sequence. The phylogenetic relationships among 11 whiteflies and Drosophila melanogaster were inferred by maximum likelihood and Bayesian inference methods. Aleurocanthus camelliae and T. acaciae form a sister group, and all three Bemisia tabaci and two Bemisia afer strains gather together. These results are identical to the relationships inferred from gene order. We inferred that gene rearrangement plays an important role in the mt genome evolved from whiteflies.

  5. The Complete Mitochondrial Genome of Aleurocanthus camelliae: Insights into Gene Arrangement and Genome Organization within the Family Aleyrodidae

    PubMed Central

    Chen, Shi-Chun; Wang, Xiao-Qing; Li, Pin-Wu; Hu, Xiang; Wang, Jin-Jun; Peng, Ping

    2016-01-01

    There are numerous gene rearrangements and transfer RNA gene absences existing in mitochondrial (mt) genomes of Aleyrodidae species. To understand how mt genomes evolved in the family Aleyrodidae, we have sequenced the complete mt genome of Aleurocanthus camelliae and comparatively analyzed all reported whitefly mt genomes. The mt genome of A. camelliae is 15,188 bp long, and consists of 13 protein-coding genes, two rRNA genes, 21 tRNA genes and a putative control region (GenBank: KU761949). The tRNA gene, trnI, has not been observed in this genome. The mt genome has a unique gene order and shares most gene boundaries with Tetraleurodes acaciae. Nineteen of 21 tRNA genes have the conventional cloverleaf shaped secondary structure and two (trnS1 and trnS2) lack the dihydrouridine (DHU) arm. Using ARWEN and homologous sequence alignment, we have identified five tRNA genes and revised the annotation for three whitefly mt genomes. This result suggests that most absent genes exist in the genomes and have not been identified, due to be lack of technology and inference sequence. The phylogenetic relationships among 11 whiteflies and Drosophila melanogaster were inferred by maximum likelihood and Bayesian inference methods. Aleurocanthus camelliae and T. acaciae form a sister group, and all three Bemisia tabaci and two Bemisia afer strains gather together. These results are identical to the relationships inferred from gene order. We inferred that gene rearrangement plays an important role in the mt genome evolved from whiteflies. PMID:27827992

  6. Improved DNA barcoding method for Bemisia tabaci and related Aleyrodidae: Development of universal and Bemisia tabaci biotype-specific mitochondrial cytochrome c oxidase I polymerase chain reaction primers

    USDA-ARS?s Scientific Manuscript database

    Whitefly is the common name of heteropteran insects that comprise the Aleyrodidae family composed of over 160 genera and 1500 different species. The mitochondrial cytochome c oxidase I (mtCOI) sequence has been used extensively in whitefly phylogenetic comparisons and in biotype identification of th...

  7. Diversity and evolution of the Wolbachia endosymbionts of Bemisia (Hemiptera: Aleyrodidae) whiteflies

    PubMed Central

    Bing, Xiao-Li; Xia, Wen-Qiang; Gui, Jia-Dong; Yan, Gen-Hong; Wang, Xiao-Wei; Liu, Shu-Sheng

    2014-01-01

    Wolbachia is the most prevalent symbiont described in arthropods to date. Wolbachia can manipulate host reproduction, provide nutrition to insect hosts and protect insect hosts from pathogenic viruses. So far, 13 supergroups of Wolbachia have been identified. The whitefly Bemisia tabaci is a complex containing more than 28 morphologically indistinguishable cryptic species. Some cryptic species of this complex are invasive. In this study, we report a comprehensive survey of Wolbachia in B. tabaci and its relative B. afer from 1658 insects representing 54 populations across 13 provinces of China and one state of Australia. Based on the results of PCR or sequencing of the 16S rRNA gene, the overall rates of Wolbachia infection were 79.6% and 0.96% in the indigenous and invasive Bemisia whiteflies, respectively. We detected a new Wolbachia supergroup by sequencing five molecular marker genes including 16S rRNA, groEL, gltA, hcpA, and fbpA genes. Data showed that many protein-coding genes have limitations in detecting and classifying newly identified Wolbachia supergroups and thus raise a challenge to the known Wolbachia MLST standard analysis system. Besides, the other Wolbachia strains detected from whiteflies were clustered into supergroup B. Phylogenetic trees of whitefly mitochondrial cytochrome oxidase subunit I and Wolbachia multiple sequencing typing genes were not congruent. In addition, Wolbachia was also detected outside the special bacteriocytes in two cryptic species by fluorescence in situ hybridization, indicating the horizontal transmission of Wolbachia. Our results indicate that members of Wolbachia are far from well explored. PMID:25077022

  8. Genome Evolution in the Primary Endosymbiont of Whiteflies Sheds Light on Their Divergence

    PubMed Central

    Santos-Garcia, Diego; Vargas-Chavez, Carlos; Moya, Andrés; Latorre, Amparo; Silva, Francisco J.

    2015-01-01

    Whiteflies are important agricultural insect pests, whose evolutionary success is related to a long-term association with a bacterial endosymbiont, Candidatus Portiera aleyrodidarum. To completely characterize this endosymbiont clade, we sequenced the genomes of three new Portiera strains covering the two extant whitefly subfamilies. Using endosymbiont and mitochondrial sequences we estimated the divergence dates in the clade and used these values to understand the molecular evolution of the endosymbiont coding sequences. Portiera genomes were maintained almost completely stable in gene order and gene content during more than 125 Myr of evolution, except in the Bemisia tabaci lineage. The ancestor had already lost the genetic information transfer autonomy but was able to participate in the synthesis of all essential amino acids and carotenoids. The time of divergence of the B. tabaci complex was much more recent than previous estimations. The recent divergence of biotypes B (MEAM1 species) and Q (MED species) suggests that they still could be considered strains of the same species. We have estimated the rates of evolution of Portiera genes, synonymous and nonsynonymous, and have detected significant differences among-lineages, with most Portiera lineages evolving very slowly. Although the nonsynonymous rates were much smaller than the synonymous, the genomic dN/dS ratios were similar, discarding selection as the driver of among-lineage variation. We suggest variation in mutation rate and generation time as the responsible factors. In conclusion, the slow evolutionary rates of Portiera may have contributed to its long-term association with whiteflies, avoiding its replacement by a novel and more efficient endosymbiont. PMID:25716826

  9. Identification of a whitefly species by genomic and behavioral studies

    USGS Publications Warehouse

    Perring, T.M.; Cooper, A.D.; Rodriguez, R.J.; Farrar, C.A.; Bellows, T.S.

    1993-01-01

    An introduced whitefly species, responsible for over a half billion dollars in damage to U.S. agricultural production in 1991, is morphologically indistinguishable from Bemisia tabaci (Gennadius). However, with the use of polymerase chain reaction-based DNA differentiation tests, allozymic frequency analyses, crossing experiments, and mating behavior studies, the introduced whitefly is found to be a distinct species. Recognition of this new species, the silverleaf whitefly, is critical in the search for management options.

  10. Baseline Susceptibilities of B- and Q-biotype Bemisia tabaci to anthranilic diamides

    USDA-ARS?s Scientific Manuscript database

    Development of pyriproxyfen and neonicotinoid resistance in the B biotype whitefly and recent introduction of the Q biotype are threatening the current whitefly management programs in Arizona. Whether the novel anthranilic diamides chlorantraniliprole and cyantraniliprole can be integrated into the ...

  11. Field evaluation of Cucurbit yellow stunting disorder virus transmission by Bemisia tabaci.

    PubMed

    Castle, S J; Palumbo, J P; Merten, P

    2017-03-22

    Cucurbit yellow stunting disorder virus (CYSDV) is a whitefly-transmitted Crinivirus (Closteroviridae) that impacts melon production in many parts of the world including the USA. It has been responsible for melon crop loss in the southwestern U.S. since 2006 when it was first identified. Control strategies have revolved mainly around chemical control, but research to identify suitable products and approaches to implementing them has lagged. The current study investigated the performance of four systemic insecticides in the field while concurrently tracking CYSDV disease progression after controlled and natural whitefly inoculation of young melon plants. Assessments of virus incidence were made using two different visual observation methods in concert with ELISA analyses of leaf disks samples collected biweekly. Infection rates were consistently lowest in plots treated with the butenolide insecticide flupyradifurone while dinotefuran was second in efficacy measures. Flupyradifurone also held whitefly densities to their lowest numbers relative to the other treatments. Two other insecticides, imidacloprid and cyantraniliprole, exacerbated virus incidence in multiple trials. Further investigation into the anomalous finding of increased virus incidence due to insecticide application is ongoing.

  12. LAMP (Loop-mediated isothermal amplification of DNA) - A technique for biotype discrimination in Bemisia tabaci

    USDA-ARS?s Scientific Manuscript database

    Loop-mediated isothermal amplification of DNA (LAMP) can amplify a target DNA sequence at a constant temperature in about 1 hour. LAMP technology has great potential for agricultural applications because of the need for rapid and inexpensive diagnoses. Assays based on LAMP technology are well suited...

  13. Temperature stress effects in Bemisia tabaci (Hemiptera: Aleyrodidae) type B whiteflies

    USDA-ARS?s Scientific Manuscript database

    Oxidative stress occurs in response to changes in the redox equilibiurm, which may be caused by increases in reactive oxygen species (ROS), a decrease in antioxidant protection or failure of cells to repair oxidative damage. ROS are either free radicals, reactive molecules containing oxygen atoms or...

  14. Temperature stress, anti-oxidative enzyme activity and virus acquisition in Bemisia tabaci (Hemiptera: Aleyrodidae)

    USDA-ARS?s Scientific Manuscript database

    In most eukaryotic systems, antioxidants provide protection when cells are exposed to stressful environmental conditions. Antioxidants, such as superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase, function in a stepwise series with SOD initially preventing oxidative damage by conve...

  15. Evolution and homoplasy at the bem6 microsatellite locus in three Bemisia tabaci cryptic species

    USDA-ARS?s Scientific Manuscript database

    The evolution of individual microsatellite loci is often complex and homoplasy is common but often goes undetected. Sequencing alleles at a microsatellite locus can provide a more complete picture of the common evolutionary mechanisms occurring at that locus and can reveal cases of homoplasy. Within...

  16. Response of Bemisia tabaci (Hemiptera: Aleyrodidae) to vapor pressure deficit: Oviposition, immature survival and body size

    USDA-ARS?s Scientific Manuscript database

    Ambient temperature is an abiotic factor that has been studied extensively in insect biology and population dynamics while relatively little investigations have been carried out on the impact of ambient moisture. Whiteflies cause major agricultural problems in environments ranging from arid to humi...

  17. Baseline susceptibilities of B- and Q-biotype Bemisia tabaci to anthranilic diamides in Arizona.

    PubMed

    Li, Xianchun; Degain, Benjamin A; Harpold, Virginia S; Marçon, Paula G; Nichols, Robert L; Fournier, Alfred J; Naranjo, Steven E; Palumbo, John C; Ellsworth, Peter C

    2012-01-01

    Development of pyriproxyfen and neonicotinoid resistance in the B-biotype whitefly and recent introduction of the Q biotype have the potential to threaten current whitefly management programs in Arizona. The possibility of integrating the novel anthranilic diamides chlorantraniliprole and cyantraniliprole into the current program to tackle these threats largely depends on whether these compounds have cross-resistance with pyriproxyfen and neonicotinoids in whiteflies. To address this question, the authors bioassayed a susceptible B-biotype strain, a pyriproxyfen-resistant B-biotype strain, four multiply resistant Q-biotype strains and 16 B-biotype field populations from Arizona with a systemic uptake bioassay developed in the present study. The magnitude of variations in LC(50) and LC(99) among the B-biotype populations or the Q-biotype strains was less than fivefold and tenfold, respectively, for both chlorantraniliprole and cyantraniliprole. The Q-biotype strains were relatively more tolerant than the B-biotype populations. No correlations were observed between the LC(50) (or LC(99)) values of the two diamides against the B- and Q-biotype populations tested and their survival rates at a discriminating dose of pyriproxyfen or imidacloprid. These results indicate the absence of cross-resistance between the two anthranilic diamides and the currently used neonicotinoids and pyriproxyfen. Future variation in susceptibility of field populations to chlorantraniliprole and cyantraniliprole could be documented according to the baseline susceptibility range of the populations tested in this study. Copyright © 2011 Society of Chemical Industry.

  18. Effect of foliar application of pyrifluquinazon on Bemisia tabaci (MED whitefly) and Amblyseius swirskii, 2016

    USDA-ARS?s Scientific Manuscript database

    With the overall goal to integrate the predatory mite Amblyseius swirskii in the management program of MED whitefly, the specific objective of this study was to evaluate pyrifluquinazon, a pyridine insecticide for whitefly control, and assess its compatibility with swirskii mite, and assess its comp...

  19. A Tomato necrotic dwarf virus isolate from Datura with poor transmissibility by the whitefly, Bemisia tabaci

    USDA-ARS?s Scientific Manuscript database

    Tomato necrotic dwarf virus (ToNDV); genus Torradovirus, is a whitefly-transmitted virus that caused significant losses for tomato production in the Imperial Valley of California during the 1980s. The virus causes severe stunting, dwarfing of leaves, foliar and fruit necrosis, and greatly reduced f...

  20. Evaluation of potential new sources of melon host plant resistance to the whitefly, Bemisia tabaci

    USDA-ARS?s Scientific Manuscript database

    Melon (Cucumis melo L.) genotypes that support fewer numbers of whitefly could reduce the frequency or the amount of insecticide applications required to keep the insects in check, as was the case with cotton where measurable resistance to whitefly in some genotypes reduced the number of sprays, thu...

  1. Evaluation of mustard plants and other products to control sweetpotato whitefly, Bemisia tabaci

    USDA-ARS?s Scientific Manuscript database

    A major insect pest of vegetables and horticultural crops in the southeast US is the sweetpotato whitefly.Scientists at the USDA-Agriculture Research Service, Center for Veterinary Entomology, Gainesaville, Florida, evaluated the effect of giant red mustard plants and commercial products to control ...

  2. Field evaluation of Bemisia parasitoids in Texas

    USDA-ARS?s Scientific Manuscript database

    Two methods were employed to assess the potential of candidate parasitoid species/strains to parasitize B. tabaci under field conditions in Texas. Sleeve cage evaluations were conducted in kale, cantaloupe melons, and cotton in 1994–1995. In kale, the highest parasitism rates were observed for two s...

  3. Genetics and Genomics of Cotton Leaf Curl Disease, Its Viral Causal Agents and Whitefly Vector: A Way Forward to Sustain Cotton Fiber Security.

    PubMed

    Rahman, Mehboob-Ur-; Khan, Ali Q; Rahmat, Zainab; Iqbal, Muhammad A; Zafar, Yusuf

    2017-01-01

    Cotton leaf curl disease (CLCuD) after its first epidemic in 1912 in Nigeria, has spread to different cotton growing countries including United States, Pakistan, India, and China. The disease is of viral origin-transmitted by the whitefly Bemisia tabaci, which is difficult to control because of the prevalence of multiple virulent viral strains or related species. The problem is further complicated as the CLCuD causing virus complex has a higher recombination rate. The availability of alternate host crops like tomato, okra, etc., and practicing mixed type farming system have further exaggerated the situation by adding synergy to the evolution of new viral strains and vectors. Efforts to control this disease using host plant resistance remained successful using two gene based-resistance that was broken by the evolution of new resistance breaking strain called Burewala virus. Development of transgenic cotton using both pathogen and non-pathogenic derived approaches are in progress. In future, screening for new forms of host resistance, use of DNA markers for the rapid incorporation of resistance into adapted cultivars overlaid with transgenics and using genome editing by CRISPR/Cas system would be instrumental in adding multiple layers of defense to control the disease-thus cotton fiber production will be sustained.

  4. Climate Change: Life history adaptation by a global whitefly, Bemisia tabaci, with rising temperature and carbon dioxide

    USDA-ARS?s Scientific Manuscript database

    Introduction: Climate change can have direct and indirect impacts on living organisms. A rise in ambient temperature and elevated carbon dioxide (CO2) concentrations due to global warming may have assorted impacts on arthropods such as altered life cycles, altered reproductive patterns, and change...

  5. High Ozone (O3) Affects the Fitness Associated with the Microbial Composition and Abundance of Q Biotype Bemisia tabaci

    PubMed Central

    Hong, Yanyun; Yi, Tuyong; Tan, Xiaoling; Zhao, Zihua; Ge, Feng

    2016-01-01

    Ozone (O3) affects the fitness of an insect, such as its development, reproduction and protection against fungal pathogens, but the mechanism by which it does so remains unclear. Here, we compared the fitness (i.e., the growth and development time, reproduction and protection against Beauveria bassiana (B. bassiana) of Q biotype whiteflies fumigated under hO3 (280 ± 20 ppb) and control O3 (50 ± 10 ppb) concentrations. Moreover, we determined that gene expression was related to development, reproduction and immunity to B. bassiana and examined the abundance and composition of bacteria and fungi inside of the body and on the surface of the Q biotype whitefly. We observed a significantly enhanced number of eggs that were laid by a female, shortened developmental time, prolonged adult lifespan, decreased weight of one eclosion, and reduced immunity to B. bassiana in whiteflies under hO3, but hO3 did not significantly affect the expression of genes related to development, reproduction and immunity. However, hO3 obviously changed the composition of the bacterial communities inside of the body and on the surface of the whiteflies, significantly reducing Rickettsia and enhancing Candidatus_Cardinium. Similarly, hO3 significantly enhanced Thysanophora penicillioides from the Trichocomaceae family and reduced Dothideomycetes (at the class level) inside of the body. Furthermore, positive correlations were found between the abundance of Candidatus_Cardinium and the female whitefly ratio and the fecundity of a single female, and positive correlations were found between the abundance of Rickettsia and the weight of adult whiteflies just after eclosion and immunity to B. bassiana. We conclude that hO3 enhances whitefly development and reproduction but impairs immunity to B. bassiana, and our results also suggest that the changes to the microbial environments inside of the body and on the surface could be crucial factors that alter whitefly fitness under hO3. PMID:27799921

  6. First report of Bemisia tabaci biotype Q in Costa Rica and detection of viruliferous whiteflies in greenhouses

    USDA-ARS?s Scientific Manuscript database

    Whiteflies are a complex that comprises multiple species and biotypes or races which are capable of affecting crops by phloem feeding, virus transmission and promotion of fungal colonization. The distribution of these pests is worldwide. In Costa Rica, a country located in the tropics, the most prob...

  7. Evolution and homoplasy at the Bem6 microsatellite locus in three sweetpotato whitefly (Bemisia tabaci) cryptic species

    USDA-ARS?s Scientific Manuscript database

    The evolution of individual microsatellite loci is often complex and homoplasy is common but often goes undetected. Sequencing alleles at a microsatellite locus can provide a more complete picture of the common evolutionary mechanisms occurring at that locus and can reveal cases of homoplasy. Within...

  8. Homopteran vector biomarkers for efficient circulative plant virus transmission are conserved in multiple aphid species and the whitefly Bemisia tabaci

    USDA-ARS?s Scientific Manuscript database

    Plant viruses in the families Luteoviridae and Geminiviridae are phloem restricted and are transmitted in a persistent, circulative manner by homopteran insects. Using fluorescence 2-D difference gel electrophoresis to compare the proteomes of genotypes in an F2 population of S. graminum that segre...

  9. Fourth International Bemisia Workshop International Whitefly Genomics Workshop

    USDA-ARS?s Scientific Manuscript database

    Invited speakers from around the world presented research and management tactics conducted in their respective geographic regions and areas of expertise. Sessions were arranged with a slate of invited speakers followed by discussion, comments, and questions. Attendance was truly international with m...

  10. Enhanced symbiotic nitrogen fixation with P. syringae pv tabaci

    SciTech Connect

    Langston-Unkefer, P.J.; Knight, T.J. New Mexico State Univ., Las Cruces ); Sengupta-Gopalan, C. )

    1989-04-01

    Infestation of legumes such as alfalfa and soybeans with the plant pathogen Pseudomonas syringae pv. tabaci is accompanied by increased plant growth, nodulation, overall nitrogen fixation, and total assimilated nitrogen. These effects are observed only in plants infested with Tox{sup +} pathogen; the toxin is tabtoxinine-{beta}-lactam, an active site-directed irreversible inhibitor of glutamine synthetase. The key to the legumes survival of this treatment is the insensitivity of the nodule-specific form of glutamine synthetase to the toxin. As expected, significant changes are observed in ammonia assimilation in these plants. The biochemical and molecular biological consequences of this treatment are being investigated.

  11. Detection of Gene Flow from Sexual to Asexual Lineages in Thrips tabaci (Thysanoptera: Thripidae).

    PubMed

    Li, Xiao-Wei; Wang, Ping; Fail, Jozsef; Shelton, Anthony M

    2015-01-01

    Populations of Thrips tabaci are known to have two sympatric but genetically isolated reproductive modes, arrhenotoky (sexual reproduction) and thelytoky (asexual reproduction). Herein, we report behavioral, ecological and genetic studies to determine whether there is gene flow between arrhenotokous and thelytokous T. tabaci. We did not detect significant preference by arrhenotokous males to mate with females of a particular reproductive mode, nor did we detect significant behavioral differences between arrhenotokous males mated with arrhenotokous or thelytokous females in their pre-copulation, copulation duration and mating frequency. Productive gene transfer resulting from the mating between the two modes was experimentally confirmed. Gene transfer from arrhenotokous T. tabaci to thelytokous T. tabaci was further validated by confirmation of the passage of the arrhenotokous male-originated nuclear gene (histone H3 gene) allele to the F2 generation. These behavioral, ecological and genetic studies confirmed gene transfer from the sexual arrhenotokous mode to the asexual thelytokous mode of T. tabaci in the laboratory. These results demonstrate that asexual T. tabaci populations may acquire genetic variability from sexual populations, which could offset the long-term disadvantage of asexual reproduction.

  12. Detection of Gene Flow from Sexual to Asexual Lineages in Thrips tabaci (Thysanoptera: Thripidae)

    PubMed Central

    Li, Xiao-Wei; Wang, Ping; Fail, Jozsef; Shelton, Anthony M.

    2015-01-01

    Populations of Thrips tabaci are known to have two sympatric but genetically isolated reproductive modes, arrhenotoky (sexual reproduction) and thelytoky (asexual reproduction). Herein, we report behavioral, ecological and genetic studies to determine whether there is gene flow between arrhenotokous and thelytokous T. tabaci. We did not detect significant preference by arrhenotokous males to mate with females of a particular reproductive mode, nor did we detect significant behavioral differences between arrhenotokous males mated with arrhenotokous or thelytokous females in their pre-copulation, copulation duration and mating frequency. Productive gene transfer resulting from the mating between the two modes was experimentally confirmed. Gene transfer from arrhenotokous T. tabaci to thelytokous T. tabaci was further validated by confirmation of the passage of the arrhenotokous male-originated nuclear gene (histone H3 gene) allele to the F2 generation. These behavioral, ecological and genetic studies confirmed gene transfer from the sexual arrhenotokous mode to the asexual thelytokous mode of T. tabaci in the laboratory. These results demonstrate that asexual T. tabaci populations may acquire genetic variability from sexual populations, which could offset the long-term disadvantage of asexual reproduction. PMID:26375283

  13. Metabolic coevolution in the bacterial symbiosis of whiteflies and related plant sap-feeding insects

    USDA-ARS?s Scientific Manuscript database

    In animals dependent on intracellular bacteria with very small genomes, the host cell is adapted to support the function of its bacterial symbionts, but the molecular basis of these adaptations is poorly understood. We investigated the metabolic coevolution between the whitefly Bemisia tabaci and th...

  14. Seasonal Changes in Thrips tabaci Population Structure in Two Cultivated Hosts

    PubMed Central

    Nault, Brian A.; Kain, Wendy C.; Wang, Ping

    2014-01-01

    Thrips tabaci is a major pest of high-value vegetable crops and understanding its population genetics will advance our knowledge about its ecology and management. Mitochondrial cytochrome oxidase subunit I (COI) gene sequence was used as a molecular marker to analyze T. tabaci populations from onion and cabbage fields in New York. Eight COI haplotypes were identified in 565 T. tabaci individuals collected from these fields. All T. tabaci were thelytokous and genetically similar to those originating from hosts representing seven plant families spanning five continents. The most dominant haplotype was NY-HT1, accounting for 92 and 88% of the total individuals collected from onion fields in mid-summer in 2005 and 2007, respectively, and 100 and 96% of the total in early fall in 2005 and 2007, respectively. In contrast, T. tabaci collected from cabbage fields showed a dynamic change in population structure from mid-summer to early fall. In mid-summer, haplotype NY-HT2 was highly abundant, accounting for 58 and 52% of the total in 2005 and 2007, respectively, but in early fall it decreased drastically to 15 and 7% of the total in 2005 and 2007, respectively. Haplotype NY-HT1 accounted for 12 and 46% of the total in cabbage fields in mid-summer of 2005 and 2007, respectively, but became the dominant haplotype in early fall accounting for 81 and 66% of the total in 2005 and 2007, respectively. Despite the relative proximity of onion and cabbage fields in the western New York landscape, T. tabaci populations differed seasonally within each cropping system. Differences may have been attributed to better establishment of certain genotypes on specific hosts or differing colonization patterns within these cropping systems. Future studies investigating temporal changes in T. tabaci populations on their major hosts in these ecosystems are needed to better understand host-plant utilization and implications for population management. PMID:24992484

  15. Temporal Effects of a Begomovirus Infection and Host Plant Resistance on the Preference and Development of an Insect Vector, Bemisia tabaci, and Implications for Epidemics

    PubMed Central

    Legarrea, Saioa; Barman, Apurba; Marchant, Wendy; Diffie, Stan; Srinivasan, Rajagopalbabu

    2015-01-01

    Persistent plant viruses, by altering phenotypic and physiological traits of their hosts, could modulate the host preference and fitness of hemipteran vectors. A majority of such modulations increase vector preference for virus-infected plants and improve vector fitness, ultimately favouring virus spread. Nevertheless, it remains unclear how these virus-induced modulations on vectors vary temporally, and whether host resistance to the pathogen influences such effects. This study addressed the two questions using a Begomovirus-whitefly-tomato model pathosystem. Tomato yellow leaf curl virus (TYLCV) -susceptible and TYLCV-resistant tomato genotypes were evaluated by whitefly-mediated transmission assays. Quantitative PCR revealed that virus accumulation decreased after an initial spike in all genotypes. TYLCV accumulation was less in resistant than in susceptible genotypes at 3, 6, and 12 weeks post inoculation (WPI). TYLCV acquisition by whiteflies over time from resistant and susceptible genotypes was also consistent with virus accumulation in the host plant. Furthermore, preference assays indicated that non-viruliferous whiteflies preferred virus-infected plants, whereas viruliferous whiteflies preferred non-infected plants. However, this effect was prominent only with the susceptible genotype at 6 WPI. The development of whiteflies on non-infected susceptible and resistant genotypes was not significantly different. However, developmental time was reduced when a susceptible genotype was infected with TYLCV. Together, these results suggest that vector preference and development could be affected by the timing of infection and by host resistance. These effects could play a crucial role in TYLCV epidemics. PMID:26529402

  16. Methodology for developing life tables for sessile insects in the field using the Whitefly, Bemisia tabaci, in cotton as a model system

    USDA-ARS?s Scientific Manuscript database

    Life tables provide a means of measuring the schedules of birth and death from populations over time. They also can be used to quantify the sources and rates of mortality in populations, which has a variety of applications in ecology, including agricultural ecosystems. Horizontal, or cohort-based, l...

  17. Reduction of viral load in whitefly (Bemisia tabaci Gen.) feeding on RNAi-mediated bean golden mosaic virus resistant transgenic bean plants.

    PubMed

    de Paula, Nayhanne T; de Faria, Josias C; Aragão, Francisco J L

    2015-12-02

    The RNAi concept was explored to silence the rep gene from the bean golden mosaic virus (BGMV) and a genetically modified (GM) bean immune to the virus was previously generated. We investigated if BGMV-viruliferous whiteflies would reduce viral amount after feeding on GM plants. BGMV DNA amount was significantly reduced in whiteflies feeding in GM-plants (compared with insects feeding on non-GM plants) for a period of 4 and 8 days in 52% and 84% respectively.

  18. Two flagellar stators and their roles in motility and virulence in Pseudomonas syringae pv. tabaci 6605.

    PubMed

    Kanda, Eiko; Tatsuta, Takafumi; Suzuki, Tomoko; Taguchi, Fumiko; Naito, Kana; Inagaki, Yoshishige; Toyoda, Kazuhiro; Shiraishi, Tomonori; Ichinose, Yuki

    2011-02-01

    The motor proteins around the flagellar basal body consist of two cytoplasmic membrane proteins, MotA and MotB, and function as a complex that acts as the stator to generate the torque that drives rotation. Genome analysis of several Pseudomonas syringae pathovars revealed that there are two sets of genes encoding motor proteins: motAB and motCD. Deduced amino acid sequences for MotA/B and MotC/D showed homologies to the H(+)-driven stator from Escherichia coli and Na(+)-driven stator from Vibrio alginolyticus, respectively. However, the swimming motility of P. syringae pv. tabaci (Pta) 6605 was inhibited by the protonophore carbonyl cyanide m-chlorophenylhydrazone but not by the sodium stator-specific inhibitor phenamil. To identify a gene encoding the stator protein required for motility, ∆motAB, ∆motCD, and ∆motABCD mutants were generated. The ∆motCD mutant had remarkably reduced and the ∆motABCD mutant completely abolished swimming motilities, whereas the ∆motAB mutant retained some degree of these abilities. The ∆motCD and ∆motABCD mutants did not produce N-acyl-homoserine lactones (AHLs), quorum-sensing molecules in this pathogen, and remarkably reduced the ability to cause disease in host tobacco leaves, as we previously observed in the ∆fliC mutant strain. These results strongly indicate that both stator pairs in Pta 6605 are proton-dependent and that MotCD is important for not only flagellar motility but also for production of AHLs and the ability to cause disease in host plants.

  19. Enterobacter tabaci sp. nov., a novel member of the genus Enterobacter isolated from a tobacco stem.

    PubMed

    Duan, Yan-Qing; Zhou, Xing-Kui; Di-Yan, Li; Li, Qing-Qing; Dang, Li-Zhi; Zhang, Yong-Guang; Qiu, Li-Hong; Nimaichand, Salam; Li, Wen-Jun

    2015-11-01

    A Gram-stain negative, motile, rod-shaped bacterium, designated strain YIM Hb-3(T), was isolated from the stem of a tobacco plant. The strain was observed to form convex, circular and yellow-colored colonies. The predominant respiratory quinone was identified as Q-8. The major fatty acids (>5%) detected were C(16:1)ω7c and/or C(16:1)ω6c (summed feature 3), C(16:0), C(17:0)cyclo, C(18:1)ω7c and/or C(18:1)ω6c (summed feature 8), C(14:0)3-OH and/or iso-C(16:1)I (summed feature 2), C(14:0) and C(12:0). The genomic DNA G+C content was determined to be 54.8 mol%. Phylogenetic trees based on 16S rRNA gene sequences and multilocus sequence analysis showed that strain YIM Hb-3(T) had the closest phylogenetic relationship with Enterobacter mori LMG 25706(T). DNA-DNA relatedness value between strain YIM Hb-3(T) and E. mori LMG 25706(T) was 46.9 ± 3.8%. On the basis of phenotypic and chemotaxonomic data, phylogenetic analysis, and DNA-DNA relatedness value, strain YIM Hb-3(T) is considered to represent a novel species of the genus Enterobacter, for which the name Enterobacter tabaci sp. nov. is proposed. The type strain is YIM Hb-3(T) (=KACC 17832(T) =KCTC 42694(T)).

  20. Mass-rearing Bemisia parasitoids for support of classical and augmentative biological control programs

    USDA-ARS?s Scientific Manuscript database

    The development of efficient mass-rearing systems for Bemisia parasitoids was crucial for the implementation of the classical and augmentative biological control programs for this exotic pest. Early work relied on adapting methods for the production of Encarsia formosa (Gahan) for the greenhouse whi...

  1. Evaluation of selected commercial oils as oviposition deterrents against the silverleaf whitefly, Bemisia argentifolii (Hemiptera:Aleyrodidae)

    USDA-ARS?s Scientific Manuscript database

    Silverleaf whitefly (SLWF), Bemisia argentifolii Bellows and Perring, remains a serious economic pest of vegetables and ornamentals worldwide. Conventional chemical control of whiteflies is often rendered ineffective due to rapid development of insecticide resistance. However, relatively little res...

  2. Restricted Gene Flow among Lineages of Thrips tabaci Supports Genetic Divergence Among Cryptic Species Groups

    PubMed Central

    Jacobson, Alana L.; Nault, Brian A.; Vargo, Edward L.; Kennedy, George G.

    2016-01-01

    Knowledge of the relative influence of population- versus species-level genetic variation is important to understand patterns of phenotypic variation and ecological relationships that exist among and within morphologically indistinguishable cryptic species and subspecies. In the case of cryptic species groups that are pests, such knowledge is also essential for devising effective population management strategies. The globally important crop pest Thrips tabaci is a taxonomically difficult group of putatively cryptic species. This study examines population genetic structure of T. tabaci and reproductive isolation among lineages of this species complex using microsatellite markers and mitochondrial COI sequences. Overall, genetic structure supports T. tabaci as a cryptic species complex, although limited interbreeding occurs between different clonal groups from the same lineage as well as between individuals from different lineages. These results also provide evidence that thelytoky and arrhenotoky are not fixed phenotypes among members of different T. tabaci lineages that have been generally associated with either reproductive mode. Possible biological and ecological factors contributing to these observations are discussed. PMID:27690317

  3. Thrips tabaci Population Genetic Structure and Polyploidy in Relation to Competency as a Vector of Tomato Spotted Wilt Virus

    PubMed Central

    Jacobson, Alana L.; Booth, Warren; Vargo, Edward L.; Kennedy, George G.

    2013-01-01

    Knowledge of population-level genetic differences can help explain variation among populations of insect vectors in their role in the epidemiology of specific viruses. Variation in competency to transmit Tomato spotted wilt virus (TSWV) that exists among populations of Thrips tabaci has been associated with the presence of cryptic species that exhibit different modes of reproduction and host ranges. However, recent findings suggest that vector competency of T. tabaci at any given location depends on the thrips and virus populations that are present. This study characterizes the population genetic structure of T. tabaci collected from four locations in North Carolina and examines the relationship between population genetic structure and variation in TSWV transmission by T. tabaci. Mitochondrial COI sequence analysis revealed the presence of two genetically distinct groups with one characterized by thelytokous, parthenogenetic reproduction and the other by arrhenotokous, sexual reproduction. Using a set of 11 microsatellite markers that we developed to investigate T. tabaci population genetic structure, we identified 17 clonal groups and found significant genetic structuring among the four NC populations that corresponded to the geographic locations where the populations were collected. Application of microsatellite markers also led to the discovery of polyploidy in this species. All four populations contained tetraploid individuals, and three contained both diploid and tetraploid individuals. Analysis of variation in transmission ofTSWV among isofemale lines initiated with individuals used in this study revealed that ‘clone assignment,’ ‘virus isolate’ and their interaction significantly influenced vector competency. These results highlight the importance of interactions between specific T. tabaci clonal types and specific TSWV isolates underlying transmission of TSWV by T. tabaci. PMID:23365671

  4. Colonization of onions by endophytic fungi and their impacts on the biology of Thrips tabaci.

    PubMed

    Muvea, Alexander M; Meyhöfer, Rainer; Subramanian, Sevgan; Poehling, Hans-Michael; Ekesi, Sunday; Maniania, Nguya K

    2014-01-01

    Endophytic fungi, which live within host plant tissues without causing any visible symptom of infection, are important mutualists that mediate plant-herbivore interactions. Thrips tabaci (Lindeman) is one of the key pests of onion, Allium cepa L., an economically important agricultural crop cultivated worldwide. However, information on endophyte colonization of onions, and their impacts on the biology of thrips feeding on them, is lacking. We tested the colonization of onion plants by selected fungal endophyte isolates using two inoculation methods. The effects of inoculated endophytes on T. tabaci infesting onion were also examined. Seven fungal endophytes used in our study were able to colonize onion plants either by the seed or seedling inoculation methods. Seed inoculation resulted in 1.47 times higher mean percentage post-inoculation recovery of all the endophytes tested as compared to seedling inoculation. Fewer thrips were observed on plants inoculated with Clonostachys rosea ICIPE 707, Trichoderma asperellum M2RT4, Trichoderma atroviride ICIPE 710, Trichoderma harzianum 709, Hypocrea lixii F3ST1 and Fusarium sp. ICIPE 712 isolates as compared to those inoculated with Fusarium sp. ICIPE 717 and the control treatments. Onion plants colonized by C. rosea ICIPE 707, T. asperellum M2RT4, T. atroviride ICIPE 710 and H. lixii F3ST1 had significantly lower feeding punctures as compared to the other treatments. Among the isolates tested, the lowest numbers of eggs were laid by T. tabaci on H. lixii F3ST1 and C. rosea ICIPE 707 inoculated plants. These results extend the knowledge on colonization of onions by fungal endophytes and their effects on Thrips tabaci.

  5. Colonization of Onions by Endophytic Fungi and Their Impacts on the Biology of Thrips tabaci

    PubMed Central

    Muvea, Alexander M.; Meyhöfer, Rainer; Subramanian, Sevgan; Poehling, Hans-Michael; Ekesi, Sunday; Maniania, Nguya K.

    2014-01-01

    Endophytic fungi, which live within host plant tissues without causing any visible symptom of infection, are important mutualists that mediate plant–herbivore interactions. Thrips tabaci (Lindeman) is one of the key pests of onion, Allium cepa L., an economically important agricultural crop cultivated worldwide. However, information on endophyte colonization of onions, and their impacts on the biology of thrips feeding on them, is lacking. We tested the colonization of onion plants by selected fungal endophyte isolates using two inoculation methods. The effects of inoculated endophytes on T. tabaci infesting onion were also examined. Seven fungal endophytes used in our study were able to colonize onion plants either by the seed or seedling inoculation methods. Seed inoculation resulted in 1.47 times higher mean percentage post-inoculation recovery of all the endophytes tested as compared to seedling inoculation. Fewer thrips were observed on plants inoculated with Clonostachys rosea ICIPE 707, Trichoderma asperellum M2RT4, Trichoderma atroviride ICIPE 710, Trichoderma harzianum 709, Hypocrea lixii F3ST1 and Fusarium sp. ICIPE 712 isolates as compared to those inoculated with Fusarium sp. ICIPE 717 and the control treatments. Onion plants colonized by C. rosea ICIPE 707, T. asperellum M2RT4, T. atroviride ICIPE 710 and H. lixii F3ST1 had significantly lower feeding punctures as compared to the other treatments. Among the isolates tested, the lowest numbers of eggs were laid by T. tabaci on H. lixii F3ST1 and C. rosea ICIPE 707 inoculated plants. These results extend the knowledge on colonization of onions by fungal endophytes and their effects on Thrips tabaci. PMID:25254657

  6. Negative Regulation of Pathogenesis in Pseudomonas syringae pv. tabaci 11528 by ATP-Dependent Lon Protease

    PubMed Central

    Yang, Hyun Ju; Lee, Jun Seung; Cha, Ji Young; Baik, Hyung Suk

    2011-01-01

    Pseudomonas syringae pv. tabaci causes wildfire disease in tobacco plants. The hrp pathogenicity island (hrp PAI) of P. syringae pv. tabaci encodes a type III secretion system (TTSS) and its regulatory system, which are required for pathogenesis in plants. Three important regulatory proteins- HrpR, HrpS, and HrpL-have been identified to activate hrp PAI gene expression. The bacterial Lon protease regulates the expression of various genes. To investigate the regulatory mechanism of the Lon protease in P. syringae pv. tabaci 11528, we cloned the lon gene, and then a Δlon mutant was generated by allelic exchange. lon mutants showed increased UV sensitivity, which is a typical feature of such mutants. The Δlon mutant produced higher levels of tabtoxin than the wild-type. The lacZ gene was fused with hrpA promoter and activity of β-galactosidase was measured in hrp-repressing and hrp-inducing media. The Lon protease functioned as a negative regulator of hrp PAI under hrp-repressing conditions. We found that strains with lon disruption elicited the host defense system more rapidly and strongly than the wild-type strain, suggesting that the Lon protease is essential for systemic pathogenesis. PMID:21904881

  7. Transcriptome changes occurred in the whitefly, B. tabaci MEAM1 in response to feeding on melon infected with the crinivirus, CYSDV

    USDA-ARS?s Scientific Manuscript database

    CYSDV, a crinivirus transmitted by the whitefly, B. tabaci, causes widespread losses in melon and other cucurbits. The virus emerged in the southwestern United States in 2006. It established in crops and weeds, and is transmitted to cucurbits by the resident population of B. tabaci MEAM1 each year. ...

  8. Performance of arrhenotokous and thelytokous Thrips tabaci (Thysanoptera: Thripidae) on onion and cabbage and its implications on evolution and pest management.

    PubMed

    Li, Xiao-Wei; Fail, Jozsef; Wang, Ping; Feng, Ji-Nian; Shelton, A M

    2014-08-01

    Onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), is an important pest on onion and cabbage. Two reproductive modes--arrhenotoky and thelytoky--are found in this species and co-occur in the field. We compared life table traits between arrhenotokous and thelytokous T. tabaci on cabbage and onion. Experiments were conducted in cages to determine which reproductive mode is more competitive. Additionally, host adaption of the arrhenotokous and thelytokous T. tabaci between onion and cabbage was investigated. On onion, arrhenotokous T. tabaci performed better than thelytokous T. tabaci, while on cabbage the opposite occurred. When comparing life table and demographic growth parameters (net reproductive rates R(o), mean generation time T, the intrinsic rate of natural increase r(m), finite rate of increase A, and population doubling time T(d)) on different host plants, we found that arrhenotokous T. tabaci performed better on onion than on cabbage, whereas thelytokous T. tabaci performed better on cabbage than on onion. Host-related performance differences in this species suggest that the divergence between two reproductive modes might be associated with host adaption. Pest management strategies for this global pest should recognize that the two reproductive modes can impact population dynamics on different crops.

  9. Phylogenetic Analysis and Rapid Identification of the Whitefly, Bemisia afer, in China

    PubMed Central

    Chu, Dong; Liu, Guoxia; Wan, Fanghao; Tao, Yunli; Gill, Ray J

    2010-01-01

    The phylogenetic relationship between the whitefly Bemisia afer (Priesner & Hosny) (Hemiptera: Aleyrodidae) from China and other populations among the world were analyzed based on the mitochondrial cytochrome oxidase I (mtCOI) gene. Phylogenetic analysis of mtCOI sequences and those of reference B. afer sequences showed that the populations of the species could be separated into 5 clades (I–V). There were at least two clades of the species from China (IV and V). These data suggested that B. afer might be a species complex. The Chinese B. afer populations were most divergent with B. afer from the United Kingdom and African countries. The distance between the Chinese B. afer (IV and V) and clades I, II, and III is more than 32%, while the distance among clades I, II, III is lower than 7.7%. A new set of primers specific to B. afer was designed to amplify a region of approximately 400 bp to discriminate B. afer from other Bemisia species in China based on mtCOI sequences. PMID:20673071

  10. Thrips tabaci (Thysanoptera: Thripidae) and Iris yellow spot virus associated with onion transplants, onion volunteers, and weeds in Colorado

    USDA-ARS?s Scientific Manuscript database

    Thrips tabaci infestation was determined on onion transplants received in Colorado during March and April from out of state sources (Imperial Valley, near Phoenix Arizona, and southern Texas) during 2004 to 2008. In the five years of the study, 50% to 100% of the transplant lots sampled were found ...

  11. Evaluation of onion germplasm for resistance to Iris yellow spot (Iris yellow spot virus) and onion thrips, Thrips tabaci

    USDA-ARS?s Scientific Manuscript database

    Onion (Allium cepa L.) is the most economically important monocot outside of the grasses. This important crop suffers severe damage from onion thrips (Thrips tabaci), a cosmopolitan and polyphagous insect pest. In addition to direct feeding damages, onion thrips has emerged as the principal vector o...

  12. Transmission of Pantoea ananatis and P. agglomerans, causal agents of center rot of onion (Allium cepa), by onion thrips (Thrips tabaci) through feces.

    PubMed

    Dutta, B; Barman, A K; Srinivasan, R; Avci, U; Ullman, D E; Langston, D B; Gitaitis, R D

    2014-08-01

    Frankliniella fusca, the tobacco thrips, has been shown to acquire and transmit Pantoea ananatis, one of the causal agents of the center rot of onion. Although Thrips tabaci, the onion thrips, is a common pest of onions, its role as a vector of P. ananatis has been unknown. The bacterium, P. agglomerans, is also associated with the center rot of onion, but its transmission by thrips has not been previously investigated. In this study, we investigated the relationship of T. tabaci with P. ananatis and P. agglomerans. Surface-sterilized T. tabaci were provided with various acquisition access periods (AAP) on onion leaves inoculated with either P. ananatis or P. agglomerans. A positive exponential relationship was observed between thrips AAP duration and P. ananatis (R² = 0.967; P = 0.023) or P. agglomerans acquisition (R² = 0.958; P = 0.017). Transmission experiments conducted with T. tabaci adults indicated that 70% of the seedlings developed center rot symptoms 15 days after inoculation. Immunofluorescence microscopy with antibodies specific to P. ananatis revealed that the bacterium was localized only in the gut of T. tabaci adults. Mechanical inoculation of onion seedlings with fecal rinsates alone produced center rot but not with salivary secretions. Together these results suggested that T. tabaci could efficiently transmit P. ananatis and P. agglomerans.

  13. Gac two-component system in Pseudomonas syringae pv. tabaci is required for virulence but not for hypersensitive reaction.

    PubMed

    Marutani, Mizuri; Taguchi, Fumiko; Ogawa, Yujiro; Hossain, Md Mijan; Inagaki, Yoshishige; Toyoda, Kazuhiro; Shiraishi, Tomonori; Ichinose, Yuki

    2008-04-01

    Pseudomonas syringae pv. tabaci 6605 causes wildfire disease on host tobacco plants. To investigate the regulatory mechanism of the expression of virulence, Gac two-component system-defective mutants, DeltagacA and DeltagacS, and a double mutant, DeltagacADeltagacS, were generated. These mutants produced smaller amounts of N-acyl homoserine lactones required for quorum sensing, had lost swarming motility, and had reduced expression of virulence-related hrp genes and the algT gene required for exopolysaccharide production. The ability of the mutants to cause disease symptoms in their host tobacco plant was remarkably reduced, while they retained the ability to induce hypersensitive reaction (HR) in the nonhost plants. These results indicated that the Gac two-component system of P. syringae pv. tabaci 6605 is indispensable for virulence on the host plant, but not for HR induction in the nonhost plants.

  14. Arsenophonus GroEL interacts with CLCuV and is localized in midgut and salivary gland of whitefly B. tabaci.

    PubMed

    Rana, Vipin Singh; Singh, Shalini Thakur; Priya, Natarajan Gayatri; Kumar, Jitendra; Rajagopal, Raman

    2012-01-01

    Cotton leaf curl virus (CLCuV) (Gemininiviridae: Begomovirus) is the causative agent of leaf curl disease in cotton plants (Gossypium hirsutum). CLCuV is exclusively transmitted by the whitefly species B. tabaci (Gennadius) (Hemiptera: Alerodidae). B. tabaci contains several biotypes which harbor dissimilar bacterial endo-symbiotic community. It is reported that these bacterial endosymbionts produce a 63 kDa chaperon GroEL protein which binds to geminivirus particles and protects them from rapid degradation in gut and haemolymph. In biotype B, GroEL protein of Hamiltonella has been shown to interact with Tomato yellow leaf curl virus (TYLCV). The present study was initiated to find out whether endosymbionts of B. tabaci are similarly involved in CLCuV transmission in Sriganganagar (Rajasthan), an area endemic with cotton leaf curl disease. Biotype and endosymbiont diversity of B. tabaci were identified using MtCO1 and 16S rDNA genes respectively. Analysis of our results indicated that the collected B. tabaci population belong to AsiaII genetic group and harbor the primary endosymbiont Portiera and the secondary endosymbiont Arsenophonus. The GroEL proteins of Portiera and Arsenophonus were purified and in-vitro interaction studies were carried out using pull down and co-immunoprecipitation assays. In-vivo interaction was confirmed using yeast two hybrid system. In both in-vitro and in-vivo studies, the GroEL protein of Arsenophonus was found to be interacting with the CLCuV coat protein. Further, we also localized the presence of Arsenophonus in the salivary glands and the midgut of B. tabaci besides the already reported bacteriocytes. These results suggest the involvement of Arsenophonus in the transmission of CLCuV in AsiaII genetic group of B. tabaci.

  15. Arsenophonus GroEL Interacts with CLCuV and Is Localized in Midgut and Salivary Gland of Whitefly B. tabaci

    PubMed Central

    Rana, Vipin Singh; Kumar, Jitendra; Rajagopal, Raman

    2012-01-01

    Cotton leaf curl virus (CLCuV) (Gemininiviridae: Begomovirus) is the causative agent of leaf curl disease in cotton plants (Gossypium hirsutum). CLCuV is exclusively transmitted by the whitefly species B. tabaci (Gennadius) (Hemiptera: Alerodidae). B. tabaci contains several biotypes which harbor dissimilar bacterial endo-symbiotic community. It is reported that these bacterial endosymbionts produce a 63 kDa chaperon GroEL protein which binds to geminivirus particles and protects them from rapid degradation in gut and haemolymph. In biotype B, GroEL protein of Hamiltonella has been shown to interact with Tomato yellow leaf curl virus (TYLCV). The present study was initiated to find out whether endosymbionts of B. tabaci are similarly involved in CLCuV transmission in Sriganganagar (Rajasthan), an area endemic with cotton leaf curl disease. Biotype and endosymbiont diversity of B. tabaci were identified using MtCO1 and 16S rDNA genes respectively. Analysis of our results indicated that the collected B. tabaci population belong to AsiaII genetic group and harbor the primary endosymbiont Portiera and the secondary endosymbiont Arsenophonus. The GroEL proteins of Portiera and Arsenophonus were purified and in-vitro interaction studies were carried out using pull down and co-immunoprecipitation assays. In-vivo interaction was confirmed using yeast two hybrid system. In both in-vitro and in-vivo studies, the GroEL protein of Arsenophonus was found to be interacting with the CLCuV coat protein. Further, we also localized the presence of Arsenophonus in the salivary glands and the midgut of B. tabaci besides the already reported bacteriocytes. These results suggest the involvement of Arsenophonus in the transmission of CLCuV in AsiaII genetic group of B. tabaci. PMID:22900008

  16. Effect of temperature on development and reproduction of Proprioseiopsis asetus (Acari: Phytoseiidae) fed on asparagus thrips, Thrips tabaci.

    PubMed

    Huang, Jian Hua; Freed, Shoaib; Wang, Li Si; Qin, Wen Jing; Chen, Hong Fan; Qin, Hou Guo

    2014-10-01

    Thrips tabaci Lindeman (Thysanoptera: Thripidae) is one of the most important pests of asparagus in China. In this study the effects of five constant temperatures (15, 20, 25, 30 and 35 °C) on the growth, survivorship and reproduction of Proprioseiopsis asetus (Chant) (Acari: Phytoseiidae) fed on T. tabaci was examined under laboratory conditions. Development time of immatures decreased with increasing temperature. The lower egg-to-adult developmental threshold (T 0) and thermal constant (K) of P. asetus were estimated at 15.2 °C and 75.8 degree days by means of a linear model. Fertilized females fed on T. tabaci produced offspring of both sexes, whereas the offspring sex ratio [♀/(♀ + ♂)] of P. asetus at 20-35 °C was female-biased (0.68-0.78) and not significantly influenced by temperature. Survivorship during immature development was significantly influenced by temperature, and was especially low at 15 °C. Pre- and post-oviposition periods of fertilized females shortened with the increase in temperature. The longest oviposition period was 20.4 days, at 25 °C, whereas at 15 °C the mites did not reproduce. Maximum average life time fecundity and mean daily fecundity was recorded at 25 and 35 °C, respectively; the intrinsic rate of increase ranged from 0.05 (20 °C) to 0.17 (35 °C). The results indicate the capability of P. asetus to develop and reproduce at a broad range of temperatures, especially above 25 °C, which can be used for better management of T. tabaci in asparagus.

  17. Transcriptome analysis of the whitefly, Bemisia tabaci MEAM1 on tomato infected with the crinivirus, Tomato chlorosis virus, identifies a temporal shift in gene expression and differential regulation of novel orphan genes

    USDA-ARS?s Scientific Manuscript database

    Whiteflies threaten agricultural crop production worldwide, are polyphagous in nature, and transmit hundreds of plant viruses. Little information exists on how whitefly gene expression is altered due to feeding on plants infected with a semipersistently transmitted virus. Tomato chlorosis virus (T...

  18. Distinct sucrose isomerases catalyze trehalulose synthesis in whiteflies, Bemisia argentifolii, and Erwinia rhapontici.

    PubMed

    Salvucci, Michael E

    2003-06-01

    Isomaltulose [alpha-D-glucopyranosyl-(1,6)-D-fructofuranose] and trehalulose [alpha-D-glucopyranosyl-(1,1)-D-fructofuranose] are commercially valuable sucrose-substitutes that are produced in several microorganisms by the palI gene product, a sucrose isomerase. Trehalulose also occurs in the silverleaf whitefly, Bemisia argentifoli, as the major carbohydrate in the insect's honeydew. To determine if the enzyme that synthesizes trehalulose in whiteflies was similar to the well-characterized sucrose isomerase from microbial sources, the properties of the enzymes from whiteflies and the bacterium, Erwinia rhapontici, were compared. Partial purification of both enzymes showed that the enzyme from whiteflies was a 116 kD membrane-associated polypeptide, in contrast to the enzyme from E. rhapontici, which was soluble and 66 kD. The enzyme from E. rhapontici converted sucrose to isomaltulose and trehalulose in a 5:1 ratio, whereas the enzyme from whiteflies produced only trehalulose. Unlike the E. rhapontici enzyme, the whitefly enzyme did not convert isomaltulose to trehalulose, but both enzymes catalyzed the transfer of fructose to trehalulose using sucrose as the glucosyl donor. The results indicate that trehalulose synthase from whiteflies is structurally and functionally distinct from the sucrose isomerases described in bacteria. The whitefly enzyme is the first reported case of an enzyme that converts sucrose to exclusively trehalulose.

  19. Genetic and host-associated differentiation within Thrips tabaci Lindeman (Thysanoptera: Thripidae) and its links to Tomato spotted wilt virus-vector competence.

    PubMed

    Westmore, G C; Poke, F S; Allen, G R; Wilson, C R

    2013-09-01

    Of eight thelytokous populations of onion thrips (Thrips tabaci) collected from potato (three populations), onion (four) or Chrysanthemum (one) hosts from various regions of Australia, only those from potato were capable of transmitting Tomato spotted wilt virus (TSWV) in controlled transmission experiments. Genetic differentiation of seven of these eight populations, and nine others not tested for TSWV vector competence, was examined by comparison of the DNA sequences of mitochondrial cytochrome oxidase subunit 1 (COI) gene. All Australian populations of T. tabaci grouped within the European 'L2' clade of Brunner et al. (2004). Within this clade the seven populations from potato, the three from onion, and the four from other hosts (Chrysanthemum, Impatiens, lucerne, blackberry nightshade) clustered as three distinct sub-groupings characterised by source host. Geographical source of thrips populations had no influence on genetic diversity. These results link genetic differentiation of thelytokous T. tabaci to source host and to TSWV vector capacity for the first time.

  20. Expression of an Antimicrobial Peptide via the Chloroplast Genome to Control Phytopathogenic Bacteria and Fungi

    PubMed Central

    DeGray, Gerald; Rajasekaran, Kanniah; Smith, Franzine; Sanford, John; Daniell, Henry

    2001-01-01

    The antimicrobial peptide MSI-99, an analog of magainin 2, was expressed via the chloroplast genome to obtain high levels of expression in transgenic tobacco (Nicotiana tabacum var. Petit Havana) plants. Polymerase chain reaction products and Southern blots confirmed integration of MSI-99 into the chloroplast genome and achievement of homoplasmy, whereas northern blots confirmed transcription. Contrary to previous predictions, accumulation of MSI-99 in transgenic chloroplasts did not affect normal growth and development of the transgenic plants. This may be due to differences in the lipid composition of plastid membranes compared with the membranes of susceptible target microbes. In vitro assays with protein extracts from T1 and T2 plants confirmed that MSI-99 was expressed at high levels to provide 88% (T1) and 96% (T2) inhibition of growth against Pseudomonas syringae pv tabaci, a major plant pathogen. When germinated in the absence of spectinomycin selection, leaf extracts from T2 generation plants showed 96% inhibition of growth against P. syringae pv tabaci. In addition, leaf extracts from transgenic plants (T1) inhibited the growth of pregerminated spores of three fungal species, Aspergillus flavus, Fusarium moniliforme, and Verticillium dahliae, by more than 95% compared with non-transformed control plant extracts. In planta assays with the bacterial pathogen P. syringae pv tabaci resulted in areas of necrosis around the point of inoculation in control leaves, whereas transformed leaves showed no signs of necrosis, demonstrating high-dose release of the peptide at the site of infection by chloroplast lysis. In planta assays with the fungal pathogen, Colletotrichum destructivum, showed necrotic anthracnose lesions in non-transformed control leaves, whereas transformed leaves showed no lesions. Genetically engineering crop plants for disease resistance via the chloroplast genome instead of the nuclear genome is desirable to achieve high levels of expression

  1. Consequences of co-applying insecticides and fungicides for managing Thrips tabaci (Thysanoptera: Thripidae) on onion.

    PubMed

    Nault, Brian A; Hsu, Cynthia L; Hoepting, Christine A

    2013-07-01

    Insecticides and fungicides are commonly co-applied in a tank mix to protect onions from onion thrips, Thrips tabaci Lindeman, and foliar pathogens. Co-applications reduce production costs, but past research shows that an insecticide's performance can be reduced when co-applied with a fungicide. An evaluation was made of the effects of co-applying spinetoram, abamectin and spirotetramat with commonly used fungicides, with and without the addition of a penetrating surfactant, on onion thrips control in onion fields. Co-applications of insecticides with chlorothalonil fungicides reduced thrips control by 25-48% compared with control levels provided by the insecticides alone in three of five trials. Inclusion of a penetrating surfactant at recommended rates with the insecticide and chlorothalonil fungicide did not consistently overcome this problem. Co-applications of insecticides with other fungicides did not interfere with thrips control. Co-applications of pesticides targeting multiple organisms should be examined closely to ensure that control of each organism is not compromised. To manage onion thrips in onion most effectively, insecticides should be applied with a penetrating surfactant, and should be applied separately from chlorothalonil fungicides. © 2012 Society of Chemical Industry.

  2. Temporal dynamics of iris yellow spot virus and its vector, Thrips tabaci (Thysanoptera: Thripidae), in seeded and transplanted onion fields.

    PubMed

    Hsu, Cynthia L; Hoepting, Christine A; Fuchs, Marc; Shelton, Anthony M; Nault, Brian A

    2010-04-01

    Onion thrips, Thrips tabaci (Lindeman) (Thysanoptera: Thripidae), can reduce onion bulb yield and transmit iris yellow spot virus (IYSV) (Bunyaviridae: Tospovirus), which can cause additional yield losses. In New York, onions are planted using seeds and imported transplants. IYSV is not seed transmitted, but infected transplants have been found in other U.S. states. Transplants are also larger than seeded onions early in the season, and thrips, some of which may be viruliferous, may preferentially colonize larger plants. Limited information is available on the temporal dynamics of IYSV and its vector in onion fields. In 2007 and 2008, T. tabaci and IYSV levels were monitored in six seeded and six transplanted fields. We found significantly more thrips in transplanted fields early in the season, but by the end of the season seeded fields had higher levels of IYSV. The percentage of sample sites with IYSV-infected plants remained low (<12%) until August, when infection levels increased dramatically in some fields. The densities of adult and larval thrips in August and September were better predictors of final IYSV levels than early season thrips densities. For 2007 and 2008, the time onions were harvested may have been more important in determining IYSV levels than whether the onions were seeded or transplanted. Viruliferous thrips emigrating from harvested onion fields into nonharvested ones may be increasing the primary spread of IYSV in late-harvested onions. Managing T. tabaci populations before harvest, and manipulating the spatial arrangement of fields based on harvest date could mitigate the spread of IYSV.

  3. Type IV pilin is glycosylated in Pseudomonas syringae pv. tabaci 6605 and is required for surface motility and virulence.

    PubMed

    Nguyen, Linh Chi; Taguchi, Fumiko; Tran, Quang Minh; Naito, Kana; Yamamoto, Masanobu; Ohnishi-Kameyama, Mayumi; Ono, Hiroshi; Yoshida, Mitsuru; Chiku, Kazuhiro; Ishii, Tadashi; Inagaki, Yoshishige; Toyoda, Kazuhiro; Shiraishi, Tomonori; Ichinose, Yuki

    2012-09-01

    Type IV pilin (PilA) is a major constituent of pilus and is required for bacterial biofilm formation, surface motility and virulence. It is known that mature PilA is produced by cleavage of the short leader sequence of the pilin precursor, followed by methylation of N-terminal phenylalanine. The molecular mass of the PilA mature protein from the tobacco bacterial pathogen Pseudomonas syringae pv. tabaci 6605 (Pta 6605) has been predicted to be 12 329 Da from its deduced amino acid sequence. Previously, we have detected PilA as an approximately 13-kDa protein by immunoblot analysis with anti-PilA-specific antibody. In addition, we found the putative oligosaccharide-transferase gene tfpO downstream of pilA. These findings suggest that PilA in Pta 6605 is glycosylated. The defective mutant of tfpO (ΔtfpO) shows reductions in pilin molecular mass, surface motility and virulence towards host tobacco plants. Thus, pilin glycan plays important roles in bacterial motility and virulence. The genetic region around pilA was compared among P. syringae pathovars. The tfpO gene exists in some strains of pathovars tabaci, syringae, lachrymans, mori, actinidiae, maculicola and P. savastanoi pv. savastanoi. However, some strains of pathovars tabaci, syringae, glycinea, tomato, aesculi and oryzae do not possess tfpO, and the existence of tfpO is independent of the classification of pathovars/strains in P. syringae. Interestingly, the PilA amino acid sequences in tfpO-possessing strains show higher homology with each other than with tfpO-nonpossessing strains. These results suggest that tfpO and pilA might co-evolve in certain specific bacterial strains.

  4. Evaluating mustard as a potential companion crop for collards to control the silverleaf whitefly, Bemisia argentifolii (Hemiptera:Aleyrodidae): outdoor and olfactometer experiments.

    USDA-ARS?s Scientific Manuscript database

    Three varieties of mustard (giant red mustard, tender green mustard and ragged leaf mustard) were evaluated as possible repellent companion crops for collards against the silverleaf whitefly, Bemisia argentifolii in outdoor potted experiments and through laboratory studies using a Y-tube olfactomete...

  5. Real-time PCR protocols for the quantification of the begomovirus tomato yellow leaf curl Sardinia virus in tomato plants and in its insect vector.

    PubMed

    Noris, Emanuela; Miozzi, Laura

    2015-01-01

    Tomato yellow leaf curl Sardinia virus (TYLCSV) (Geminiviridae) is an important pathogen, transmitted by the whitefly Bemisia tabaci, that severely affects the tomato production in the Mediterranean basin. Here, we describe real-time PCR protocols suitable for relative and absolute quantification of TYLCSV in tomato plants and in whitefly extracts. Using primers and probe specifically designed for TYLCSV, the protocols for relative quantification allow to compare the amount of TYLCSV present in different plant or whitefly samples, normalized to the amount of DNA present in each sample using endogenous tomato or Bemisia genes as internal references. The absolute quantification protocol allows to calculate the number of genomic units of TYLCSV over the genomic units of the plant host (tomato), with a sensitivity of as few as ten viral genome copies per sample. The described protocols are potentially suitable for several applications, such as plant breeding for resistance, analysis of virus replication, and virus-vector interaction studies.

  6. Host range and complete genome sequence of Cucurbit chlorotic yellows virus, a new member of the genus Crinivirus.

    PubMed

    Okuda, Mitsuru; Okazaki, Shinichiro; Yamasaki, Shuichi; Okuda, Shiori; Sugiyama, Mitsuhiro

    2010-06-01

    Cucurbit chlorotic yellows virus (CCYV) causes chlorotic yellows on cucumber (Cucumis sativus) and melon (Cucumis melo) and is transmitted by Bemisia tabaci biotype B and Q whiteflies. To characterize the host range of CCYV, 21 cucurbitaceous and 12 other plant species were inoculated using whitefly vectors. All tested Cucumis spp. except Cucumis anguria and Cucumis zeyheri were systemically infected with CCYV, although infection rates varied among species. Citrullus lanatus, Cucurbita pepo, and Luffa cylindrica were susceptible to CCYV; however, the infection rates were low and symptoms were unclear. In addition to the cucurbitaceous plants, Beta vulgaris, Chenopodium amaranticolor, Chenopodium quinoa, Spinacia oleracea, Lactuca sativa, Datura stramonium, and Nicotiana benthamiana were also systemically infected by CCYV. Complete RNA1 and RNA2 were reverse-transcribed, cloned, and sequenced. CCYV RNA1 was found to be 8,607 nucleotides (nt) long and contained four open reading frames (ORFs). The first ORF spanned methyltransferase and RNA helicase domains followed by an RNA-dependent RNA polymerase domain, presumably translated by a +1 ribosomal frameshift. CCYV RNA2 was found to be 8,041 nt long and contained eight ORFs, including the hallmark gene array of the family Closteroviridae. Phylogenetic analysis demonstrated that CCYV was genetically close to Lettuce chlorosis virus, Bean yellow disorder virus, and Cucurbit yellow stunting disorder virus. Amino acid sequence similarities of representative proteins with these viruses indicated that CCYV should be classified as a distinct crinivirus species.

  7. Transcriptome changes occurred in the whitefly, B. tabaci MEAM1 in response to feeding on melon infected with the crinivirus, CYSDV

    USDA-ARS?s Scientific Manuscript database

    Cucurbit yellow stunting disorder virus (CYSDV), a crinivirus transmitted by the whitefly, B. tabaci, causes widespread losses in melon in many parts of the world. The virus emerged in the southwestern United States (Arizona and California) and western Mexico in 2006 and rapidly became established ...

  8. Suppression of plant defense responses by extracellular metabolites from Pseudomonas syringae pv. tabaci in Nicotiana benthamiana.

    PubMed

    Lee, Seonghee; Yang, Dong Sik; Uppalapati, Srinivasa Rao; Sumner, Lloyd W; Mysore, Kirankumar S

    2013-04-18

    Pseudomonas syringae pv. tabaci (Pstab) is the causal agent of wildfire disease in tobacco plants. Several pathovars of Pseudomonas syringae produce a phytotoxic extracellular metabolite called coronatine (COR). COR has been shown to suppress plant defense responses. Interestingly, Pstab does not produce COR but still actively suppresses early plant defense responses. It is not clear if Pstab produces any extracellular metabolites that actively suppress early defense during bacterial pathogenesis. We found that the Pstab extracellular metabolite extracts (Pstab extracts) remarkably suppressed stomatal closure and nonhost hypersensitive response (HR) cell death induced by a nonhost pathogen, P. syringae pv. tomato T1 (Pst T1), in Nicotiana benthamiana. We also found that the accumulation of nonhost pathogens, Pst T1 and P. syringae pv. glycinea (Psgly), was increased in N. benthamiana plants upon treatment with Pstab extracts . The HR cell death induced by Pathogen-Associated Molecular Pattern (INF1), gene-for-gene interaction (Pto/AvrPto and Cf-9/AvrCf-9) and ethanol was not delayed or suppressed by Pstab extracts. We performed metabolite profiling to investigate the extracellular metabolites from Pstab using UPLC-qTOF-MS and identified 49 extracellular metabolites from the Pstab supernatant culture. The results from gene expression profiling of PR-1, PR-2, PR-5, PDF1.2, ABA1, COI1, and HSR203J suggest that Pstab extracellular metabolites may interfere with SA-mediated defense pathways. In this study, we found that Pstab extracts suppress plant defense responses such as stomatal closure and nonhost HR cell death induced by the nonhost bacterial pathogen Pst T1 in N. benthamiana.

  9. Temperature and precipitation affect seasonal patterns of dispersing tobacco thrips, Frankliniella fusca, and onion thrips, Thrips tabaci (Thysanoptera: Thripidae) caught on sticky traps.

    PubMed

    Morsello, Shannon C; Groves, Russell L; Nault, Brian A; Kennedy, George G

    2008-02-01

    Effects of temperature and precipitation on the temporal patterns of dispersing tobacco thrips, Frankliniella fusca, and onion thrips, Thrips tabaci, caught on yellow sticky traps were estimated in central and eastern North Carolina and eastern Virginia from 1997 through 2001. The impact that these environmental factors had on numbers of F. fusca and T. tabaci caught on sticky traps during April and May was determined using stepwise regression analysis of 43 and 38 site-years of aerial trapping data from 21 and 18 different field locations, respectively. The independent variables used in the regression models included degree-days, total precipitation, and the number of days in which precipitation occurred during January through May. Each variable was significant in explaining variation for both thrips species and, in all models, degree-days was the single best explanatory variable. Precipitation had a comparatively greater effect on T. tabaci than F. fusca. The numbers of F. fusca and T. tabaci captured in flight were positively related to degree-days and the number of days with precipitation but negatively related to total precipitation. Combined in a single model, degree-days, total precipitation, and the number of days with precipitation explained 70 and 55% of the total variation in the number of F. fusca captured from 1 April through 10 May and from 1 April through 31 May, respectively. Regarding T. tabaci flights, degree-days, total precipitation, and the number of days with precipitation collectively explained 57 and 63% of the total variation in the number captured from 1 April through 10 May and from 1 April through 31 May, respectively.

  10. Influence of Bemisia argentifolii (Homoptera: Aleyrodidae) infestation and squash silverleaf disorder on zucchini seedling growth.

    PubMed

    McAuslane, Heather J; Chen, Jiang; Carle, R Bruce; Schmalstig, Judy

    2004-06-01

    We investigated the effect of different levels of infestation by whiteflies, Bemisia argentifolii Bellows & Perring, on the growth and pigment concentrations of seedlings of zucchini, Cucurbita pepo L., that differed in their tolerance to squash silverleaf disorder. Genetically similar sister lines that were either tolerant (ZUC76-SLR) or susceptible (ZUC61) to silverleaf disorder exhibited reduced plant height, internode length, plant dry weight, and petiole length in response to whitefly feeding. Similar plant growth responses to whitefly feeding were observed despite that the foliage of ZUC61 silvered severely, whereas the foliage of ZUC76-SLR showed no silvering in a greenhouse experiment conducted in the spring and showed only minimal silvering in a similar greenhouse experiment conducted in the fall. In plants of both sister lines infested with 50 pairs of whiteflies and their progeny, petioles, but not the leaf blades, of uninfested leaves had reduced chlorophyll content. In another experiment, two different genetic sources of tolerance to silverleaf disorder (ZUC33-SLR/PMR and ZUC76-SLR) and a commercial silverleaf-susceptible zucchini hybrid ('Zucchini Elite') responded similarly to whitefly feeding, except the tolerant genotypes did not exhibit leaf silvering. All genotypes, silverleaf tolerant or not, had reduced dry weight, plant height, and internode length that became more pronounced as whitefly infestation increased. All genotypes had reduced levels of chlorophylls and carotenoids in uninfested young leaf blades and petioles from infested plants. Petioles, however, were more affected by feeding than leaf blades, showing a 66% reduction in chlorophylls a+b and carotenoids at the lowest infestation level (30 pairs of whitefly and their progeny), whereas pigments in leaf blades declined more slowly in response to whitefly feeding density, averaging 14-15% less at the highest infestation level (90 pairs of whitefly and their progeny). We conclude that

  11. Molecular basis of a microbe-mediated enhancement of symbiotic N/sub 2/-fixation. [Rhizobium meliloti; Pseudomonas syringae pv. tabaci

    SciTech Connect

    Unkefer, P.J.; Knight, T.J.

    1987-04-01

    Improvement of biological nitrogen fixation represents a potential source of both increased food production and decreased dependence on costly chemical fertilizer. They report the results of an investigation of the molecular basis of a unique, microbial-mediated mechanism for increased growth and nitrogen fixation rates in alfalfa. Inoculation of alfalfa plants with both Rhizobium meliloti and Pseudomonas syringae pv tabaci provides increased growth and N/sub 2/-fixation rates of alfalfa. Tabaci produces tabtoxinine-..beta..-lactam (T..beta..L), an exocellular product and glutamine synthetase (GS) inhibitor. The association of this pathogen with nodulating alfalfa plants appears to alter the normal regulation of nitrogen fixation such that nitrogenase activity is stimulated and GS activity is inhibited. Studies of the soluble amino acids in these nodules and the activities of the ammonia assimilatory enzymes indicate alternative pathways of ammonia assimilation are being employed.

  12. Effects of selected defoliants in combination with insecticides on sweetpotato whitefly (Hemiptera: Aleyrodidae) and its parasitoids in cotton

    USDA-ARS?s Scientific Manuscript database

    Effects of two defoliants, Def (S, S, Stributylphosphorotrithioate) and Dropp (thidiazuron) alone and in combination with two commonly used insecticides, a pyrethroid, Karate (lambda-cyhalothrin) and an organophosphate, Guthion (azinphosmethyl) on sweetpotato whitefly, Bemisia tabaci Gennadius Bioty...

  13. Whitefly transmission of the Sweet potato leaf curl virus

    USDA-ARS?s Scientific Manuscript database

    The sweetpotato whitefly, Bemisia tabaci (Gennadius) is highly adaptive and polyphagous on taxonomically diverse species of plants on a global scale. This whitefly transmits numerous plant viruses, including Begomoviruses (Geminiviridae). We recently found the Sweet Potato Leaf Curl Virus (SPLCV) ...

  14. Reducing whiteflies on cucumber using intercropping with less preferred vegetables

    USDA-ARS?s Scientific Manuscript database

    The effectiveness of four less preferred vegetables – celery, asparagus lettuce, Malabar spinach, and edible amaranth – were investigated for suppression of two biotypes of sweet potato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) on cucumber, Cucumis sativus L. (Cucurbitaceae). Int...

  15. Susceptibility of ornamental pepper banker plant candidates to common greenhouse pests

    USDA-ARS?s Scientific Manuscript database

    Susceptibility of four potential ornamental pepper banker plant candidates [Black Pearl (BP), Explosive Ember (EE), Masquerade (MA), Red Missile (RM), and a commercial pepper cultivar Blitz (BL)] were evaluated against three common greenhouse pests - Bemisia tabaci, Polyphagotarsonemus latus and Fra...

  16. Action threshold for applying insect growth regulators to tomato for management of irregular ripening caused by Bemisia argentifolii (Homoptera: Aleyrodidae).

    PubMed

    Schuster, D J

    2002-04-01

    The whitefly Bemisia argentifolii Bellows & Perring is a major pest of tomatoes, causing an irregular ripening disorder characterized externally by incomplete or inhibited reddening of fruit, especially in longitudinal sections, and internally by an increase in the amount of white tissue. Experiments were undertaken during the spring and fall of 1997 and 1998 and the spring of 1999 to develop an action threshold for applying the insect growth regulators (IGRs) buprofezin and pyriproxyfen to manage B. argentifolii and irregular ripening. The IGRs were applied when predetermined thresholds were reached and were compared with a high rate of the systemic insecticide imidacloprid, which was applied at transplanting and provided season-long whitefly control. Only plots treated when the numbers of sessile nymphs (second through fourth instars) reached five per 10 leaflets consistently had both external and internal irregular ripening severity ratings similar to the imidacloprid standard. Results were similar for buprofezin and pyriproxyfen even though the modes of action differ. The five nymphs per 10 leaflets threshold lends itself to field scouting because nymphal counts completed in the field using the unaided eye supplemented with a 10x hand lens were linearly and significantly related to counts completed in the laboratory with a dissecting microscope.

  17. Molecular basis for thermoprotection in Bemisia: structural differences between whitefly ketose reductase and other medium-chain dehydrogenases/reductases.

    PubMed

    Wolfe, G R; Smith, C A; Hendrix, D L; Salvucci, M E

    1999-02-01

    The silverleaf whitefly (Bemisia argentifolii, Bellows and Perring) accumulates sorbitol as a thermoprotectant in response to elevated temperature. Sorbitol synthesis in this insect is catalyzed by an unconventional ketose reductase (KR) that uses NADPH to reduce fructose. A cDNA encoding the NADPH-KR from adult B. argentifolii was cloned and sequenced to determine the primary structure of this enzyme. The cDNA encoded a protein of 352 amino acids with a calculated molecular mass of 38.2 kDa. The deduced amino acid sequence of the cDNA shared 60% identity with sheep NAD(+)-dependent sorbitol dehydrogenase (SDH). Residues in SDH involved in substrate binding were conserved in the whitefly NADPH-KR. An important structural difference between the whitefly NADPH-KR and NAD(+)-SDHs occurred in the nucleotide-binding site. The Asp residue that coordinates the adenosyl ribose hydroxyls in NAD(+)-dependent dehydrogenases (including NAD(+)-SDH), was replaced by an Ala in the whitefly NADPH-KR. The whitefly NADPH-KR also contained two neutral to Arg substitutions within four residues of the Asp to Ala substitution. Molecular modeling indicated that addition of the Arg residues and loss of the Asp decreased the electric potential of the adenosine ribose-binding pocket, creating an environment favorable for NADPH-binding. Because of the ability to use NADPH, the whitefly NADPH-KR synthesizes sorbitol under physiological conditions, unlike NAD(+)-SDHs, which function in sorbitol catabolism.

  18. Influence of cover crop and intercrop systems on Bemisia argentifolli (Hemiptera: Aleyrodidae) infestation and associated squash silverleaf disorder in zucchini.

    PubMed

    Manandhar, Roshan; Hooks, Cerruti R R; Wright, Mark G

    2009-04-01

    Field experiments were conducted to evaluate the effects of cover cropping and intercropping on population densities of silverleaf whitefly, Bemisia argentifolli Bellow and Perring, and the incidence of squash silverleaf disorder (SSL) in zucchini, Cucurbita pepo L., in Oahu, HI. Two cover crops, buckwheat (BW), Fagopyrum esculentum Moench, and white clover (WC), Trifolium repens L., or sunn hemp (SH), Crotolaria juncea L., and an intercropped vegetable, okra, Abelmonchus esculentus L., were evaluated during the 2003, 2005, and 2006 growing seasons, respectively. Population densities of whiteflies and SSL severity varied during the three field experiments. In 2003, the severity of SSL and percentage of leaves displaying symptoms were significantly lower on zucchini plants in WC than BW plots throughout the crops' growth cycle. Additionally, the percentage of leaves per plant displaying SSL symptoms was significantly greater in bare-ground (BG) compared with the pooled BW and WC treatments on each inspection date. In 2005, zucchini intercropped with okra had lower numbers of adult whiteflies and resulted in significantly lower severity of SSL than pooled BW and WC treatments. During 2006, zucchini grown with SH had significantly lower numbers of all whitefly stages (i.e., egg, immature, and adult) and less SSL severity symptoms than BW. Despite these differences in whitefly numbers and SSL severity, marketable yields were not significantly lower in BW compared with WC or SH treatment plots during the study. The mechanisms underlying these results and the feasibility of using cover crops and intercrops to manage B. argentifolli and SSL are discussed.

  19. Onion thrips (Thrips tabaci (Thysanoptera: Thripidae)) in cabbage on Prince Edward Island: observations on planting date and variety choice.

    PubMed

    Blatt, Suzanne; Ryan, Andrew; Adams, Shelley; Driscoll, Joanne

    2015-01-01

    Onion thrips (Thrips tabaci Lindeman (Thysanoptera: Thripidae)) can be a pest in organic onion production on Prince Edward Island. This study was to examine the effect of planting time and variety on infestation levels and damage by onion thrips on cabbage (Brassicae oleracea capitala (L.)). A field site was planted with 2 main and 8 lesser varieties of cabbage over 4 planting dates. Some varieties were short season and harvested on July 31 with longer season varieties harvested on September 2. Blue sticky traps were used to capture thrips migrating into the field site from July 22-September 2. Traps were counted weekly and cabbage heads within the field site were visually surveyed for thrips. At harvest, heads were weighed and measured, thrips damage was assessed then the head was dissected and thrips counted on the first four layers of the head. Thrips exhibited a preference for Lennox over Bronco throughout the season although thrips populations were not high enough to effect economic damage in 2014. Planting date influenced cabbage head weight and size with later plantings yielding the largest heads. Use of planting date and variety to avoid thrips populations is discussed.

  20. N-acylhomoserine lactone-regulation of genes mediating motility and pathogenicity in Pseudomonas syringae pathovar tabaci 11528.

    PubMed

    Cheng, Feifei; Ma, Anzhou; Luo, Jinxue; Zhuang, Xuliang; Zhuang, Guoqiang

    2017-01-29

    Pseudomonas syringae pathovar tabaci 11528 (P. syringae 11528) is a phytopathogen that causes wild-fire disease in soybean and tobacco plants. It utilizes a cell density-dependent regulation system known as quorum sensing (QS). In its QS system, the psyI is responsible for the biosynthesis of N-acylhomoserine lactones (AHLs). By comparing the transcripts from P. syringae 11528 wild-type strain with those of the ΔpsyI mutant using RNA sequencing (RNA-seq) technology, 1118 AHL-regulated genes were identified in the transition from exponential to stationary growth phase. Numerous AHL-regulated genes involved in pathogenicity were negatively controlled, including genes linked to flagella, chemotaxis, pilus, extracellular polysaccharides, secretion systems, and two-component system. Moreover, gene ontology and pathway enrichment analysis revealed that the most pronounced regulation was associated with bacterial motility. Finally, phenotypic assays showed that QS-regulated traits were involved in epiphytic growth of pathogens and disease development in plants. These findings imply that the AHL-mediated QS system in P. syringae 11528 plays significant roles in distinct stages of interactions between plants and pathogens, including early plant colonization and late plant infection.

  1. High-level of resistance to spinosad, emamectin benzoate and carbosulfan in populations of Thrips tabaci collected in Israel.

    PubMed

    Lebedev, Galina; Abo-Moch, Fauzi; Gafni, Guy; Ben-Yakir, David; Ghanim, Murad

    2013-02-01

    The onion thrips, Thrips tabaci Lindeman, is a major pest of several crop plants in the genus Allium, such as onions, garlic and chives. In Israel, these crops are grown in open fields and in protected housing. This thrips is usually controlled by the application of chemical insecticides. In recent years, spinosad, emamectin benzoate and carbosulfan have been the major insecticides used for the control of the onion thrips. In the last 4 years, growers of chives and green onion from several regions of Israel have reported a significant decrease in the efficacy of insecticides used to control the onion thrips. The susceptibility of 14 populations of the onion thrips, collected mainly from chives between the years 2007 and 2011, to spinosad, emamectin benzoate and carbosulfan was tested using a laboratory bioassay. The majority of the populations showed significant levels of resistance to at least one of the insecticides. LC(50) values calculated for two of the studied populations showed that the resistance factor for spinosad compared with the susceptible population is 21 393, for carbosulfan 54 and for emamectin benzoate 36. Only two populations, collected from organic farms, were susceptible to the insecticides tested. This is the first report of a high resistance level to spinosad, the major insecticide used to control the onion thrips. Resistance cases to spinosad were associated with failures to control the pest. Populations resistant to spinosad also had partial or complete resistance to other insecticides used for controlling the onion thrips. Copyright © 2012 Society of Chemical Industry.

  2. Tissue-specific changes of glutamine synthetase activity in oats after rhizosphere infestation by Pseudomonas syringae pv. tabaci. Final report

    SciTech Connect

    Knight, T.J.; Temple, S.; Sengupta-Gopalan, C.

    1996-05-15

    Oats (Avena sativa L. lodi) tolerant of rhizosphere infestation by Pseudomonas syringae pv. tabaci when challenged by the pathogen experience tissue-specific alterations of ammonia assimilatory capabilities. Altered ammonia assimilatory potentials between root and leaf tissue result from selective inactivation of glutamine synthetase (GS) by the toxin Tabtoxinine-B-lactam (TBL). Root GS is sensitive and leaf GSs are resistant to TBL inactivation. With prolonged challenge by the pathogen root GS activity decreases but leaf GS specific activity increase. Higher leaf GS activity is due to decreased rates of degradation rather than increased GS synthesis. Higher leaf GS activity and elevated levels of GS polypeptide appear to result from a limited interaction between GS and TBL leading to the accumulation of a less active but more stable GS holoenzyme. Tolerant challenged oats besides surviving rhizosphere infestation, experience enhanced growth. A strong correlation exists between leaf GS activity and whole plant fresh weight, suggesting that tissue-specific changes in ammonia assimilatory capability provides the plant a more efficient mechanism for uptake and utilization of nitrogen.

  3. Insects' RNA Profiling Reveals Absence of "Hidden Break" in 28S Ribosomal RNA Molecule of Onion Thrips, Thrips tabaci.

    PubMed

    Macharia, Rosaline Wanjiru; Ombura, Fidelis Levi; Aroko, Erick Onyango

    2015-01-01

    With an exception of aphids, insects' 28S rRNA is thought to harbor a "hidden break" which cleaves under denaturing conditions to comigrate with 18S rRNA band to exhibit a degraded appearance on native agarose gels. The degraded appearance confounds determination of RNA integrity in laboratories that rely on gel electrophoresis. To provide guidelines for RNA profiles, RNA from five major insect orders, namely, Diptera, Hemiptera, Thysanoptera, Hymenoptera, and Lepidoptera, was compared under denaturing and nondenaturing conditions. This study confirmed that although present in most of insect's RNA, the "hidden break" is absent in the 28S rRNA of onion thrips, Thrips tabaci. On the other hand, presence of "hidden break" was depicted in whiteflies' 28S rRNA despite their evolutionary grouping under same order with aphids. Divergence of 28S rRNA sequences confirms variation of both size and composition of gap region among insect species. However, phylogeny reconstruction does not support speciation as a possible source of the hidden break in insect's 28S rRNA. In conclusion, we show that RNA from a given insect order does not conform to a particular banding profile and therefore this approach cannot be reliably used to characterize newly discovered species.

  4. Evaluating plant and plant oil repellency against the sweetpotato whitefly

    USDA-ARS?s Scientific Manuscript database

    The sweetpotato whitefly, Bemisia tabaci is a major insect pest of vegetables world-wide. We evaluated the effect of commercial plant oils – garlic oil, hot pepper wax, and mustard oil against B. tabaci. Cucumber plants served as the control. Additional treatments included no plants or oil (clear ai...

  5. Evaluations of melon germplasm reported to exhibit host plant resistance to sweetpotato whitefly

    USDA-ARS?s Scientific Manuscript database

    Sweetpotato whitefly (MEAM1 cryptic species of Bemisia tabaci; SPWF) displaced B. tabaci biotype A in 1991 in the lower desert area of southern California and the adjoining areas of Arizona and western Mexico. The search for high-level host plant resistance to this devastating insect has been ongoin...

  6. Effect of the alpha-glucosidase inhibitor, bromoconduritol, on carbohydrate metabolism in the silverleaf whitefly, Bemisia argentifolii.

    PubMed

    Salvucci, M

    2000-11-01

    The involvement of alpha-glucosidase in the partitioning of ingested sucrose between excretion and incorporation was investigated in the silverleaf whitefly (Bemisia argentifolii). Approximately half of the alpha-glucosidase activity in adult whiteflies was soluble and the remainder was associated with membranes. In contrast, almost all of the trehalulose synthase was membrane-associated. Isoelectric focusing revealed that soluble and membrane-associated alpha-glucosidases were each composed of several isozymes in the pH 5 to 6.5 range, but the distribution of activity among the various isozymes was different. Bromoconduritol, an inhibitor of glucosidases, inhibited trehalulose synthase and alpha-glucosidase activities in whitefly extracts. Inhibition was greatest when bromoconduritol was incubated with extracts prior to the addition of sucrose, consistent with the irreversible nature of this inhibitor. Addition of bromoconduritol to artificial diets decreased the extractable trehalulose synthase and alpha-glucosidase activities by about 30 and 50%, respectively. Ingestion of bromoconduritol reduced the amount of carbohydrate excreted by about 80% without changing the distribution of the major honeydew sugars or causing an increase in the proportion of sucrose that was excreted. Ingestion of bromoconduritol did not affect respiration, the content and distribution of soluble carbohydrates in whitefly bodies, or the conversion of labeled sucrose into glucose, trehalose and isobemisiose. The results indicate that partitioning of ingested carbon between excretion and metabolism in whiteflies is highly regulated, probably involving multiple forms of alpha-glucosidase that facilitate a separation of the processes involved in the metabolic utilization of sucrose from those involved in excretion of excess carbohydrate. Arch. Insect Biochem. Physiol. 45:117-128, 2000. Published 2001 Wiley-Liss, Inc.

  7. Impact of Bemisia argentifolii (Homoptera: Auchenorrhyncha: Aleyrodidae) infestation and squash silverleaf disorder on zucchini yield and quality.

    PubMed

    Chen, Jiang; McAuslane, Heather J; Carle, R Bruce; Webb, Susan E

    2004-12-01

    Fruit yield and quality of zucchini, Cucurbita pepo L., plants infested with Bemisia argentifolii Bellows & Perring were evaluated in a screenhouse under spring and fall growing conditions by using closely related sister lines that were either susceptible (ZUC61) or tolerant (ZUC76-SLR) to squash silverleaf disorder. Our objective was to test separately the effects of level of whitefly infestation and expression of silverleaf symptoms on zucchini yield and quality. In a second experiment, yield and quality of fruit produced by silverleaf-tolerant zucchini genotypes incorporating two different sources of tolerance (ZUC76-SLR and ZUC33-SLR/PMR) were compared with that of 'Zucchini Elite', a silverleaf-susceptible commercial hybrid. Zucchini fruit yield was reduced in plants exposed to repeated infestations of whiteflies in spring and fall of both experiments. In addition, fruit grew to harvestable size more slowly under the highest whitefly infestations. Fruit quality was reduced at high infestations because of uneven and reduced pigmentation. The fruit yield and quality of ZUC61 and ZUC76-SLR were similarly affected by whitefly infestation despite differences in their susceptibility to squash silverleaf disorder. Fruit from infested plants showed decreased levels of chlorophyll and carotenoids causing the "blanching" of the fruit that is associated with loss of quality and reduced marketability. Leaves of infested plants of all genotypes had reduced levels of photosynthetic and photoprotectant pigments, possibly leading to reduced photosynthesis and consequently reduced yield. We conclude that feeding by high whitefly populations rather than expression of squash silverleaf disorder is responsible for yield and quality reduction in zucchini.

  8. Light Suppresses Bacterial Population through the Accumulation of Hydrogen Peroxide in Tobacco Leaves Infected with Pseudomonas syringae pv. tabaci

    PubMed Central

    Cheng, Dan-Dan; Liu, Mei-Jun; Sun, Xing-Bin; Zhao, Min; Chow, Wah S.; Sun, Guang-Yu; Zhang, Zi-Shan; Hu, Yan-Bo

    2016-01-01

    Pseudomonas syringae pv. tabaci (Pst) is a hemibiotrophic bacterial pathogen responsible for tobacco wildfire disease. Although considerable research has been conducted on the tobacco plant’s tolerance to Pst, the role of light in the responses of the photosystems to Pst infection is poorly understood. This study aimed to elucidate the underlying mechanisms of the reduced photosystem damage in tobacco leaves due to Pst infection under light conditions. Compared to dark conditions, Pst infection under light conditions resulted in less chlorophyll degradation and a smaller decline in photosynthetic function. Although the maximal quantum yield of photosystem II (PSII) and the activity of the photosystem I (PSI) complex decreased as Pst infection progressed, damage to PSI and PSII after infection was reduced under light conditions compared to dark conditions. Pst was 17-fold more abundant in tobacco leaves under dark compared to light conditions at 3 days post inoculation (dpi). Additionally, H2O2 accumulated to a high level in tobacco leaves after Pst infection under light conditions; although to a lesser extent, H2O2 accumulation was also significant under dark conditions. Pretreatment with H2O2 alleviated chlorotic lesions and decreased Pst abundance in tobacco leaves at 3 dpi under dark conditions. MV pretreatment had the same effects under light conditions, whereas 3-(3,4-dichlorophenyl)-1,1-dimethylurea pretreatment aggravated chlorotic lesions and increased the Pst population. These results indicate that chlorotic symptoms and the size of the bacterial population are each negatively correlated with H2O2 accumulation. In other words, light appears to suppress the Pst population in tobacco leaves through the accumulation of H2O2 during infection. PMID:27148334

  9. Identification of an ISR-related metabolite produced by Pseudomonas chlororaphis O6 against the wildfire pathogen pseudomonas syringae pv.tabaci in tobacco.

    PubMed

    Park, Myung Ryeol; Kim, Young Cheol; Park, Ju Yeon; Han, Song Hee; Kim, Kil Yong; Lee, Sun Woo; Kim, In Seon

    2008-10-01

    Pseudomonas chlororaphis O6 exhibits induced systemic resistance (ISR) against P. syringae pv. tabaci in tobacco. To identify one of the ISR metabolites, O6 cultures were extracted with organic solvents, and the organic extracts were subjected to column chromatography followed by spectroscopy analyses. The ISR bioassay-guided fractionation was carried out for isolation of the metabolite. Highresolution mass spectrometric analysis of the metabolite found C(9)H(9)O(3)N with an exact mass of 179.0582. LC/MS analysis in positive mode showed an (M+H)(+) peak at m/zeta 180. Nuclear magnetic resonance ((1)H, (13)C) analyses identified all protons and carbons of the metabolite. Based on the spectroscopy data, the metabolite was identified 4-(aminocarbonyl) phenylacetate (4-ACPA). 4-ACPA applied at 68.0 mM exhibited ISR activity at a level similar 1.0 mM salicylic acid. This is the first report to identify an ISR metabolite produced by P. chlororaphis O6 against the wildfire pathogen P. syringae pv. tabaci in tobacco.

  10. Host plant pubescence: Effect on silverleaf whitefly, Bemisia argentifolii, fourth instar and pharate adult dimensions and ecdysteroid titer fluctuations

    PubMed Central

    Gelman, Dale B.; Gerling, Dan

    2003-01-01

    The ability to generate physiologically synchronous groups of insects is vital to the performance of investigations designed to test insect responses to intrinsic and extrinsic stimuli. During a given instar, the silverleaf whitefly, Bemisia argentifolii, increase in depth but not in length or width. A staging system to identify physiologically synchronous 4th instar and pharate adult silverleaf whiteflies based on increasing body depth and the development of the adult eye has been described previously. This study determined the effect of host plant identity on ecdysteroid fluctuations during the 4th instar and pharate adult stages, and on the depth, length and width dimensions of 4th instar/pharate adult whiteflies. When grown on the pubescent-leafed green bean, tomato and poinsettia plants, these stages were significantly shorter and narrower, but attained greater depth than when grown on the glabrous-leafed cotton, collard and sweet potato plants. Thus, leaf pubescence is associated with reduced length and width dimensions, but increased depth dimensions in 4th instars and pharate adults. For all host plants, nymphal ecdysteroid titers peaked just prior to the initiation of adult development. However, when reared on pubescent-leafed plants, the initiation of adult development typically occurred in nymphs that had attained a depth of 0.2 to 0.25 mm (Stage 3 – 4). When reared on glabrous-leafed plants, the initiation of adult development typically occurred earlier, in nymphs that had attained a depth of only 0.15–0.18 mm (Stage 2 Old - early 3). Therefore, based on ecdysteroid concentration, it appears that Stage-2, -3 and -4/5 nymphs reared on pubescent-leafed plants are physiologically equivalent to Stage-1, -2 Young and -2 Old/3, respectively, nymphs reared on glabrous-leafed plants. The host plant affected the width but not the height of the nymphal-adult premolt ecdysteroid peak. However, leaf pubescence was not the determining factor. Thus, host plant

  11. Effect of silver reflective mulch and a summer squash trap crop on densities of immature Bemisia argentifolii (Homoptera: Aleyrodidae) on organic bean.

    PubMed

    Smith, H A; Koenig, R L; McAuslane, H J; McSorley, R

    2000-06-01

    Polyethylene mulch with a reflective silver stripe and a yellow summer squash, Cucurbita pepo L., trap crop were tested alone and in combination as tactics to reduce densities of Bemisia argentifolii Bellows & Perring eggs and nymphs, and incidence of bean golden mosaic geminivirus on snap bean, Phaseolus vulgaris L. Egg densities were consistently higher on squash than on bean, but egg densities and virus incidence were not lower on bean grown with squash than on bean grown in monoculture. Silver reflective mulch reduced egg densities compared with bean grown on bare ground during the first week after crop emergence for 2 of the 3 yr that the study was conducted. However, egg suppression by silver mulch was not enhanced by the presence of a squash trap crop when both tactics were combined. The obstacles to suppressing B. argentifolii through the use of trap crops are discussed.

  12. Prophage Genomics

    PubMed Central

    Canchaya, Carlos; Proux, Caroline; Fournous, Ghislain; Bruttin, Anne; Brüssow, Harald

    2003-01-01

    The majority of the bacterial genome sequences deposited in the National Center for Biotechnology Information database contain prophage sequences. Analysis of the prophages suggested that after being integrated into bacterial genomes, they undergo a complex decay process consisting of inactivating point mutations, genome rearrangements, modular exchanges, invasion by further mobile DNA elements, and massive DNA deletion. We review the technical difficulties in defining such altered prophage sequences in bacterial genomes and discuss theoretical frameworks for the phage-bacterium interaction at the genomic level. The published genome sequences from three groups of eubacteria (low- and high-G+C gram-positive bacteria and γ-proteobacteria) were screened for prophage sequences. The prophages from Streptococcus pyogenes served as test case for theoretical predictions of the role of prophages in the evolution of pathogenic bacteria. The genomes from further human, animal, and plant pathogens, as well as commensal and free-living bacteria, were included in the analysis to see whether the same principles of prophage genomics apply for bacteria living in different ecological niches and coming from distinct phylogenetical affinities. The effect of selection pressure on the host bacterium is apparently an important force shaping the prophage genomes in low-G+C gram-positive bacteria and γ-proteobacteria. PMID:12794192

  13. Aquaculture Genomics

    USDA-ARS?s Scientific Manuscript database

    The genomics chapter covers the basics of genome mapping and sequencing and the current status of several relevant species. The chapter briefly describes the development and use of (cDNA, BAC, etc.) libraries for mapping and obtaining specific sequence information. Other topics include comparative ...

  14. Antarctic Genomics

    PubMed Central

    Clarke, Andrew; Cockell, Charles S.; Convey, Peter; Detrich III, H. William; Fraser, Keiron P. P.; Johnston, Ian A.; Methe, Barbara A.; Murray, Alison E.; Peck, Lloyd S.; Römisch, Karin; Rogers, Alex D.

    2004-01-01

    With the development of genomic science and its battery of technologies, polar biology stands on the threshold of a revolution, one that will enable the investigation of important questions of unprecedented scope and with extraordinary depth and precision. The exotic organisms of polar ecosystems are ideal candidates for genomic analysis. Through such analyses, it will be possible to learn not only the novel features that enable polar organisms to survive, and indeed thrive, in their extreme environments, but also fundamental biological principles that are common to most, if not all, organisms. This article aims to review recent developments in Antarctic genomics and to demonstrate the global context of such studies. PMID:18629155

  15. RNA Viral Metagenome of Whiteflies Leads to the Discovery and Characterization of a Whitefly-Transmitted Carlavirus in North America

    PubMed Central

    Rosario, Karyna; Capobianco, Heather; Ng, Terry Fei Fan; Breitbart, Mya; Polston, Jane E.

    2014-01-01

    Whiteflies from the Bemisia tabaci species complex have the ability to transmit a large number of plant viruses and are some of the most detrimental pests in agriculture. Although whiteflies are known to transmit both DNA and RNA viruses, most of the diversity has been recorded for the former, specifically for the Begomovirus genus. This study investigated the total diversity of DNA and RNA viruses found in whiteflies collected from a single site in Florida to evaluate if there are additional, previously undetected viral types within the B. tabaci vector. Metagenomic analysis of viral DNA extracted from the whiteflies only resulted in the detection of begomoviruses. In contrast, whiteflies contained sequences similar to RNA viruses from divergent groups, with a diversity that extends beyond currently described viruses. The metagenomic analysis of whiteflies also led to the first report of a whitefly-transmitted RNA virus similar to Cowpea mild mottle virus (CpMMV Florida) (genus Carlavirus) in North America. Further investigation resulted in the detection of CpMMV Florida in native and cultivated plants growing near the original field site of whitefly collection and determination of its experimental host range. Analysis of complete CpMMV Florida genomes recovered from whiteflies and plants suggests that the current classification criteria for carlaviruses need to be reevaluated. Overall, metagenomic analysis supports that DNA plant viruses carried by B. tabaci are dominated by begomoviruses, whereas significantly less is known about RNA viruses present in this damaging insect vector. PMID:24466220

  16. Genome databases

    SciTech Connect

    Courteau, J.

    1991-10-11

    Since the Genome Project began several years ago, a plethora of databases have been developed or are in the works. They range from the massive Genome Data Base at Johns Hopkins University, the central repository of all gene mapping information, to small databases focusing on single chromosomes or organisms. Some are publicly available, others are essentially private electronic lab notebooks. Still others limit access to a consortium of researchers working on, say, a single human chromosome. An increasing number incorporate sophisticated search and analytical software, while others operate as little more than data lists. In consultation with numerous experts in the field, a list has been compiled of some key genome-related databases. The list was not limited to map and sequence databases but also included the tools investigators use to interpret and elucidate genetic data, such as protein sequence and protein structure databases. Because a major goal of the Genome Project is to map and sequence the genomes of several experimental animals, including E. coli, yeast, fruit fly, nematode, and mouse, the available databases for those organisms are listed as well. The author also includes several databases that are still under development - including some ambitious efforts that go beyond data compilation to create what are being called electronic research communities, enabling many users, rather than just one or a few curators, to add or edit the data and tag it as raw or confirmed.

  17. Genome Sequencing.

    PubMed

    Verma, Mansi; Kulshrestha, Samarth; Puri, Ayush

    2017-01-01

    Genome sequencing is an important step toward correlating genotypes with phenotypic characters. Sequencing technologies are important in many fields in the life sciences, including functional genomics, transcriptomics, oncology, evolutionary biology, forensic sciences, and many more. The era of sequencing has been divided into three generations. First generation sequencing involved sequencing by synthesis (Sanger sequencing) and sequencing by cleavage (Maxam-Gilbert sequencing). Sanger sequencing led to the completion of various genome sequences (including human) and provided the foundation for development of other sequencing technologies. Since then, various techniques have been developed which can overcome some of the limitations of Sanger sequencing. These techniques are collectively known as "Next-generation sequencing" (NGS), and are further classified into second and third generation technologies. Although NGS methods have many advantages in terms of speed, cost, and parallelism, the accuracy and read length of Sanger sequencing is still superior and has confined the use of NGS mainly to resequencing genomes. Consequently, there is a continuing need to develop improved real time sequencing techniques. This chapter reviews some of the options currently available and provides a generic workflow for sequencing a genome.

  18. Genome Informatics

    PubMed Central

    Winslow, Raimond L.; Boguski, Mark S.

    2005-01-01

    This article reviews recent advances in genomics and informatics relevant to cardiovascular research. In particular, we review the status of (1) whole genome sequencing efforts in human, mouse, rat, zebrafish, and dog; (2) the development of data mining and analysis tools; (3) the launching of the National Heart, Lung, and Blood Institute Programs for Genomics Applications and Proteomics Initiative; (4) efforts to characterize the cardiac transcriptome and proteome; and (5) the current status of computational modeling of the cardiac myocyte. In each instance, we provide links to relevant sources of information on the World Wide Web and critical appraisals of the promises and the challenges of an expanding and diverse information landscape. PMID:12750305

  19. Listeria Genomics

    NASA Astrophysics Data System (ADS)

    Cabanes, Didier; Sousa, Sandra; Cossart, Pascale

    The opportunistic intracellular foodborne pathogen Listeria monocytogenes has become a paradigm for the study of host-pathogen interactions and bacterial adaptation to mammalian hosts. Analysis of L. monocytogenes infection has provided considerable insight into how bacteria invade cells, move intracellularly, and disseminate in tissues, as well as tools to address fundamental processes in cell biology. Moreover, the vast amount of knowledge that has been gathered through in-depth comparative genomic analyses and in vivo studies makes L. monocytogenes one of the most well-studied bacterial pathogens. This chapter provides an overview of progress in the exploration of genomic, transcriptomic, and proteomic data in Listeria spp. to understand genome evolution and diversity, as well as physiological aspects of metabolism used by bacteria when growing in diverse environments, in particular in infected hosts.

  20. Effect of urea fertilizer application on soluble protein and free amino acid content of cotton petioles in relation to silverleaf whitefly (Bemisia argentifolii) populations.

    PubMed

    Bi, J L; Toscano, N C; Madore, M A

    2003-03-01

    The impact of urea nitrogen fertilization on silverleaf whitefly, Bemisia argentifolii Bellows & Perring, population dynamics was examined in field-grown cotton (Gossypium hirsutum L.). Five urea nitrogen treatments were tested, consisting of soil applications of 0, 112, 168, and 224 kg nitrogen per hectare, and acombined soil-foliar application of 112:17 kg nitrogen per hectare. A positive response was observed between N application rates and the measured levels of nitrate N in petioles from mature cotton leaves. Similarly, a positive response was observed between N application rates and the numbers of adult and immature whiteflies appearing during population peaks. To determine whether these positive responses were related, we measured the levels of dietary N compounds (proteins and free amino acids) that would be available for insect nutrition in cotton petioles at the different N application rates. Sampling dates and N application treatments affected levels of soluble proteins in cotton petioles, and interactions between sampling dates and treatments were significant. Across all sampling dates, the relationship between N application rates and levels of soluble proteins was linear. Sampling dates also affected levels of total and individual free amino acids. Fertilizer treatments only affected levels of total amino acids, aspartate, asparagine, and arginine plus threonine. Levels of aspartate or asparagine and the N application rates were linearly correlated. No significant correlations were observed between levels of dietary N compounds in cotton petioles and numbers of whiteflies, either adults or immatures, on the cotton plants.

  1. Genome mapping

    USDA-ARS?s Scientific Manuscript database

    Genome maps can be thought of much like road maps except that, instead of traversing across land, they traverse across the chromosomes of an organism. Genetic markers serve as landmarks along the chromosome and provide researchers information as to how close they may be to a gene or region of inter...

  2. Metabolic Coevolution in the Bacterial Symbiosis of Whiteflies and Related Plant Sap-Feeding Insects.

    PubMed

    Luan, Jun-Bo; Chen, Wenbo; Hasegawa, Daniel K; Simmons, Alvin M; Wintermantel, William M; Ling, Kai-Shu; Fei, Zhangjun; Liu, Shu-Sheng; Douglas, Angela E

    2015-09-15

    Genomic decay is a common feature of intracellular bacteria that have entered into symbiosis with plant sap-feeding insects. This study of the whitefly Bemisia tabaci and two bacteria (Portiera aleyrodidarum and Hamiltonella defensa) cohoused in each host cell investigated whether the decay of Portiera metabolism genes is complemented by host and Hamiltonella genes, and compared the metabolic traits of the whitefly symbiosis with other sap-feeding insects (aphids, psyllids, and mealybugs). Parallel genomic and transcriptomic analysis revealed that the host genome contributes multiple metabolic reactions that complement or duplicate Portiera function, and that Hamiltonella may contribute multiple cofactors and one essential amino acid, lysine. Homologs of the Bemisia metabolism genes of insect origin have also been implicated in essential amino acid synthesis in other sap-feeding insect hosts, indicative of parallel coevolution of shared metabolic pathways across multiple symbioses. Further metabolism genes coded in the Bemisia genome are of bacterial origin, but phylogenetically distinct from Portiera, Hamiltonella and horizontally transferred genes identified in other sap-feeding insects. Overall, 75% of the metabolism genes of bacterial origin are functionally unique to one symbiosis, indicating that the evolutionary history of metabolic integration in these symbioses is strongly contingent on the pattern of horizontally acquired genes. Our analysis, further, shows that bacteria with genomic decay enable host acquisition of complex metabolic pathways by multiple independent horizontal gene transfers from exogenous bacteria. Specifically, each horizontally acquired gene can function with other genes in the pathway coded by the symbiont, while facilitating the decay of the symbiont gene coding the same reaction.

  3. Two years research on efficiency of two intercrops, birdsfoot trefoil and summer savory, to reduce damage caused by onion thrips(Thrips tabaci Lindeman, Thysanoptera, Thripidae) on leek.

    PubMed

    Gombac, P; Trdan, S

    2012-01-01

    In 2009 and 2011, a field experiment was carried out at the Laboratory Field at the Biotechnical Faculty in Ljubljana, Slovenia, with the aim to investigate suitability of two intercrops, birdsfoot trefoil (Lotus corniculatus L) and summer savory (Satureja hortensis L.), for reducing damage caused by onion thrips (Thrips tabaci Lindeman) on leek (Allium porrum L.). Four leek cultivars--'Columbus', 'Forrest', 'Lancelot' and 'Lincoln'--were used in the research (Bejo Zaden B.V., Netherlands). In both years, the mean index of damage caused by feeding of the pest on the leek leaves increased from the first evaluation (13 July 2009 and 18 June 2011) in both treatments with intercrops and in control treatment (without intercrop). Leek grown with birdsfoot trefoil as intercrop was in both years statistically the least damaged from thrips. Also summer savory was efficient in the same context in comparison with control treatment. In year 2009 cultivar 'Lancelot' was the least damaged in all treatments, and in year 2011 'Lancelot' and 'Forrest'. In both years intercrop and cultivar also had a significant influence on the yield of leek. The highest yield was obtained on the control plots, meanwhile birdsfoot trefoil and summer savory were pretty competitive and yield of leek grown with them as intercrops was therefore significantly lower.

  4. Genetic analysis of genes involved in synthesis of modified 4-amino-4,6-dideoxyglucose in flagellin of Pseudomonas syringae pv. tabaci.

    PubMed

    Nguyen, Linh Chi; Yamamoto, Masanobu; Ohnishi-Kameyama, Mayumi; Andi, Salamah; Taguchi, Fumiko; Iwaki, Masako; Yoshida, Mitsuru; Ishii, Tadashi; Konishi, Tomoyuki; Tsunemi, Kazuhiko; Ichinose, Yuki

    2009-12-01

    Glycosylation of flagellin contributes to swimming and swarming motilities, adhesion ability, and consequently virulence in Pseudomonas syringae pv. tabaci 6605. Glycans attached to six serine residues are located in the central region of the flagellin polypeptide. The glycan structure at position Ser 201 was recently revealed to consist of two L-rhamnoses and one modified 4-amino-4,6-dideoxyglucose (viosamine). To clarify the mechanisms for glycosylation of modified viosamine, genes encoding dTDP-viosamine aminotransferase (vioA), dTDP-viosamine acetyltransferase (vioB), and viosamine-derivative transferase (vioT) were isolated and defective mutants were generated. MALDI-TOF-MS analysis of a lysyl endopeptidase-digested peptide including all six glycosylation sites from each flagellin indicated that the molecular masses of the three flagellin mutants were reduced with highly heterogeneous patterns at regular intervals of 146 Da in the mass range from m/z 13,819 to 15,732. The data indicated that the glycopeptides obtained from mutants had glycans consisting only of deoxyhexose instead of the flagellin glycans including the viosamine derivatives determined previously. The motility and virulence on host tobacco leaves were strongly impaired in the Delta vioA mutant and were weakly reduced in the Delta vioB and Delta vioT mutant strains. These results suggest that the genes vioA, vioB, and vioT are essential for glycosylation of flagellin, and accordingly are required for bacterial virulence.

  5. Role of type IV pili in virulence of Pseudomonas syringae pv. tabaci 6605: correlation of motility, multidrug resistance, and HR-inducing activity on a nonhost plant.

    PubMed

    Taguchi, Fumiko; Ichinose, Yuki

    2011-09-01

    To investigate the role of type IV pili in the virulence of phytopathogenic bacteria, four mutant strains for pilus biogenesis-related genes were generated in Pseudomonas syringae pv. tabaci 6605. PilA encodes the pilin protein as a major subunit of type IV pili, and the pilO product is reported to be required for pilus assembly. The fimU and fimT genes are predicted to produce minor pilins. Western blot analysis revealed that pilA, pilO, and fimU mutants but not the fimT mutant failed to construct type IV pili. Although the swimming motility of all mutant strains was not impaired in liquid medium, they showed remarkably reduced motilities on semisolid agar medium, suggesting that type IV pili are required for surface motilities. Virulence toward host tobacco plants and hypersensitive response-inducing ability in nonhost Arabidopsis leaves of pilA, pilO, and fimU mutant strains were reduced. These results might be a consequence of reduced expression of type III secretion system-related genes in the mutant strains. Further, all mutant strains showed enhanced expression of resistance-nodulation-division family members mexA, mexB, and oprM, and higher tolerance to antimicrobial compounds. These results indicate that type IV pili are an important virulence factor of this pathogen.

  6. Insects' RNA Profiling Reveals Absence of “Hidden Break” in 28S Ribosomal RNA Molecule of Onion Thrips, Thrips tabaci

    PubMed Central

    Macharia, Rosaline Wanjiru; Ombura, Fidelis Levi; Aroko, Erick Onyango

    2015-01-01

    With an exception of aphids, insects' 28S rRNA is thought to harbor a “hidden break” which cleaves under denaturing conditions to comigrate with 18S rRNA band to exhibit a degraded appearance on native agarose gels. The degraded appearance confounds determination of RNA integrity in laboratories that rely on gel electrophoresis. To provide guidelines for RNA profiles, RNA from five major insect orders, namely, Diptera, Hemiptera, Thysanoptera, Hymenoptera, and Lepidoptera, was compared under denaturing and nondenaturing conditions. This study confirmed that although present in most of insect's RNA, the “hidden break” is absent in the 28S rRNA of onion thrips, Thrips tabaci. On the other hand, presence of “hidden break” was depicted in whiteflies' 28S rRNA despite their evolutionary grouping under same order with aphids. Divergence of 28S rRNA sequences confirms variation of both size and composition of gap region among insect species. However, phylogeny reconstruction does not support speciation as a possible source of the hidden break in insect's 28S rRNA. In conclusion, we show that RNA from a given insect order does not conform to a particular banding profile and therefore this approach cannot be reliably used to characterize newly discovered species. PMID:25767721

  7. Personal genomics services: whose genomes?

    PubMed Central

    Gurwitz, David; Bregman-Eschet, Yael

    2009-01-01

    New companies offering personal whole-genome information services over the internet are dynamic and highly visible players in the personal genomics field. For fees currently ranging from US$399 to US$2500 and a vial of saliva, individuals can now purchase online access to their individual genetic information regarding susceptibility to a range of chronic diseases and phenotypic traits based on a genome-wide SNP scan. Most of the companies offering such services are based in the United States, but their clients may come from nearly anywhere in the world. Although the scientific validity, clinical utility and potential future implications of such services are being hotly debated, several ethical and regulatory questions related to direct-to-consumer (DTC) marketing strategies of genetic tests have not yet received sufficient attention. For example, how can we minimize the risk of unauthorized third parties from submitting other people's DNA for testing? Another pressing question concerns the ownership of (genotypic and phenotypic) information, as well as the unclear legal status of customers regarding their own personal information. Current legislation in the US and Europe falls short of providing clear answers to these questions. Until the regulation of personal genomics services catches up with the technology, we call upon commercial providers to self-regulate and coordinate their activities to minimize potential risks to individual privacy. We also point out some specific steps, along the trustee model, that providers of DTC personal genomics services as well as regulators and policy makers could consider for addressing some of the concerns raised below. PMID:19259127

  8. Citrus Genomics

    PubMed Central

    Talon, Manuel; Gmitter Jr., Fred G.

    2008-01-01

    Citrus is one of the most widespread fruit crops globally, with great economic and health value. It is among the most difficult plants to improve through traditional breeding approaches. Currently, there is risk of devastation by diseases threatening to limit production and future availability to the human population. As technologies rapidly advance in genomic science, they are quickly adapted to address the biological challenges of the citrus plant system and the world's industries. The historical developments of linkage mapping, markers and breeding, EST projects, physical mapping, an international citrus genome sequencing project, and critical functional analysis are described. Despite the challenges of working with citrus, there has been substantial progress. Citrus researchers engaged in international collaborations provide optimism about future productivity and contributions to the benefit of citrus industries worldwide and to the human population who can rely on future widespread availability of this health-promoting and aesthetically pleasing fruit crop. PMID:18509486

  9. Imaging genomics.

    PubMed

    Hariri, Ahmad R; Weinberger, Daniel R

    2003-01-01

    The recent completion of a working draft of the human genome sequence promises to provide unprecedented opportunities to explore the genetic basis of individual differences in complex behaviours and vulnerability to neuropsychiatric illness. Functional neuroimaging, because of its unique ability to assay information processing at the level of brain within individuals, provides a powerful approach to such functional genomics. Recent fMRI studies have established important physiological links between functional genetic polymorphisms and robust differences in information processing within distinct brain regions and circuits that have been linked to the manifestation of various disease states such as Alzheimer's disease, schizophrenia and anxiety disorders. Importantly, all of these biological relationships have been revealed in relatively small samples of healthy volunteers and in the absence of observable differences at the level of behaviour, underscoring the power of a direct assay of brain physiology like fMRI in exploring the functional impact of genetic variation.

  10. Ancient genomics

    PubMed Central

    Der Sarkissian, Clio; Allentoft, Morten E.; Ávila-Arcos, María C.; Barnett, Ross; Campos, Paula F.; Cappellini, Enrico; Ermini, Luca; Fernández, Ruth; da Fonseca, Rute; Ginolhac, Aurélien; Hansen, Anders J.; Jónsson, Hákon; Korneliussen, Thorfinn; Margaryan, Ashot; Martin, Michael D.; Moreno-Mayar, J. Víctor; Raghavan, Maanasa; Rasmussen, Morten; Velasco, Marcela Sandoval; Schroeder, Hannes; Schubert, Mikkel; Seguin-Orlando, Andaine; Wales, Nathan; Gilbert, M. Thomas P.; Willerslev, Eske; Orlando, Ludovic

    2015-01-01

    The past decade has witnessed a revolution in ancient DNA (aDNA) research. Although the field's focus was previously limited to mitochondrial DNA and a few nuclear markers, whole genome sequences from the deep past can now be retrieved. This breakthrough is tightly connected to the massive sequence throughput of next generation sequencing platforms and the ability to target short and degraded DNA molecules. Many ancient specimens previously unsuitable for DNA analyses because of extensive degradation can now successfully be used as source materials. Additionally, the analytical power obtained by increasing the number of sequence reads to billions effectively means that contamination issues that have haunted aDNA research for decades, particularly in human studies, can now be efficiently and confidently quantified. At present, whole genomes have been sequenced from ancient anatomically modern humans, archaic hominins, ancient pathogens and megafaunal species. Those have revealed important functional and phenotypic information, as well as unexpected adaptation, migration and admixture patterns. As such, the field of aDNA has entered the new era of genomics and has provided valuable information when testing specific hypotheses related to the past. PMID:25487338

  11. Ancient genomics.

    PubMed

    Der Sarkissian, Clio; Allentoft, Morten E; Ávila-Arcos, María C; Barnett, Ross; Campos, Paula F; Cappellini, Enrico; Ermini, Luca; Fernández, Ruth; da Fonseca, Rute; Ginolhac, Aurélien; Hansen, Anders J; Jónsson, Hákon; Korneliussen, Thorfinn; Margaryan, Ashot; Martin, Michael D; Moreno-Mayar, J Víctor; Raghavan, Maanasa; Rasmussen, Morten; Velasco, Marcela Sandoval; Schroeder, Hannes; Schubert, Mikkel; Seguin-Orlando, Andaine; Wales, Nathan; Gilbert, M Thomas P; Willerslev, Eske; Orlando, Ludovic

    2015-01-19

    The past decade has witnessed a revolution in ancient DNA (aDNA) research. Although the field's focus was previously limited to mitochondrial DNA and a few nuclear markers, whole genome sequences from the deep past can now be retrieved. This breakthrough is tightly connected to the massive sequence throughput of next generation sequencing platforms and the ability to target short and degraded DNA molecules. Many ancient specimens previously unsuitable for DNA analyses because of extensive degradation can now successfully be used as source materials. Additionally, the analytical power obtained by increasing the number of sequence reads to billions effectively means that contamination issues that have haunted aDNA research for decades, particularly in human studies, can now be efficiently and confidently quantified. At present, whole genomes have been sequenced from ancient anatomically modern humans, archaic hominins, ancient pathogens and megafaunal species. Those have revealed important functional and phenotypic information, as well as unexpected adaptation, migration and admixture patterns. As such, the field of aDNA has entered the new era of genomics and has provided valuable information when testing specific hypotheses related to the past.

  12. Inter-regional differences in baseline toxicity of Bemisia argentifolii (Homoptera: Aleyrodidae) to the two insect growth regulators, buprofezin and pyriproxyfen.

    PubMed

    Toscano, N C; Prabhaker, N; Castle, S J; Henneberry, T J

    2001-12-01

    A survey of 53 Bemisia argentifolii Bellows & Perring populations from different agricultural regions in California and Arizona was conducted from 1997 to 1999 to establish baseline toxicological responses to buprofezin and pyriproxyfen. Although both compounds proved to be highly toxic even in minute quantities to specific stages, geographical and temporal differences in responses were detected using a leaf spray bioassay technique. Monitoring for three years revealed that six to seven populations had higher LC50 values but not greater survival when exposed to these two insecticides. A significant difference in relative susceptibility to buprofezin was first observed in late season 1997 in San Joaquin Valley populations with LC50s ranging from 16 to 22 microg (AI)/liter(-1) compared with IC50s of 1 to 3 mg (AI)/liter(-1) in Imperial, Palo Verde Valley and Yuma populations. Whiteflies collected in subsequent years from these and other locations showed an increase in susceptibility to buprofezin. Regional differences in susceptibilities to pyriproxyfen were minimal within the same years. Three years of sampling revealed consistently higher LC50s to pyriproxyfen in populations from Palo Verde Valley, CA, compared with whiteflies from Imperial, San Joaquin Valley or Yuma. As was the case with buprofezin, a decline in LC50s to pyriproxyfen was observed in whiteflies from all locations sampled in 1999. However, no correlation was observed between buprofezin and pyriproxyfen toxicity in any of the strains. The variable toxicities observed to both compounds over a period of 3 yr may be due principally to inherent differences among geographical populations or due to past chemical use which may confer positive or negative cross-resistance to buprofezin or pyriproxyfen.

  13. GacS-dependent production of 2R, 3R-butanediol by Pseudomonas chlororaphis O6 is a major determinant for eliciting systemic resistance against Erwinia carotovora but not against Pseudomonas syringae pv. tabaci in tobacco.

    PubMed

    Han, Song Hee; Lee, Seung Je; Moon, Jae Hak; Park, Keun Hyung; Yang, Kwang Yeol; Cho, Balk Ho; Kim, Kil Yong; Kim, Yong Whan; Lee, Myung Chul; Anderson, Anne J; Kim, Young Cheol

    2006-08-01

    Root colonization by a plant-beneficial rhizobacterium, Pseudomonas chlororaphis O6, induces disease resistance in tobacco against leaf pathogens Erwinia carotovora subsp. carotovora SCC1, causing soft-rot, and Pseudomonas syringae pv. tabaci, causing wildfire. In order to identify the bacterial determinants involved in induced systemic resistance against plant diseases, extracellular components produced by the bacterium were fractionated and purified. Factors in the culture filtrate inducing systemic resistance were retained in the aqueous fraction rather than being partitioned into ethyl acetate. Fractionation on high-performance liquid chromatography followed by nuclear magnetic resonance mass spectrometry analysis identified the active compound as 2R, 3R-butanediol. 2R, 3R butanediol induced systemic resistance in tobacco to E. carotovora subsp. carotovora SCC1, but not to P. syringae pv. tabaci. Treatment of tobacco with the volatile 2R, 3R-butanediol enhanced aerial growth, a phenomenon also seen in plants colonized by P. chlororaphis O6. The isomeric form of the butanediol was important because 2S, 3S-butandiol did not affect the plant. The global sensor kinase, GacS, of P. chlororaphis O6 was a key regulator for induced systemic resistance against E. carotovora through regulation of 2R, 3R-butanediol production. This is the first report of the production of these assumed fermentation products by a pseudomonad and the role of the sensor kinase GacS in production of 2R, 3R-butanediol.

  14. Intra- and interspecific competition between western flower thrips and sweetpotato whitefly.

    PubMed

    Wu, Qing-Jun; Hou, Wen-Jie; Li, Fei; Xu, Bao-Yun; Xie, Wen; Wang, Shao-Li; Zhang, You-Jun

    2014-01-01

    The western flower thrips, Frankliniella occidentalis (Pergande), and the sweetpotato whitefly, Bemisia tabaci (Gennadius), are both invasive insect pests and are present in most of the same agricultural crops without a clear dominance of either species. Here, intra- and interspecific competition in B. tabaci and F. occidentalis was determined under controlled experiments. The results showed that intraspecific competition was distinct in F. occidentalis and that the co-occurrence of B. tabaci had a strong effect on F. occidentalis, resulting in a decrease in oviposition. Significant intraspecific competition was found in B. tabaci, and the coexistence of F. occidentalis had limited effect on the oviposition of B. tabaci. In a selective host plant preference experiment, both F. occidentalis and B. tabaci preferred eggplants most, followed by cucumbers and tomatoes. On cucumber plants, B. tabaci was predominant, whereas on eggplant and tomato plants, F. occidentalis and B. tabaci exhibited comparative competitive abilities during the initial stage. However, over time, higher numbers of B. tabaci than that of F. occidentalis were found on the two host plants. Our in vitro and potted plant experiments indicate that B. tabaci is competitively superior to F. occidentalis, which might help to explain their differential distribution patterns in China.

  15. Whole Genome Sequencing

    MedlinePlus

    ... you want to learn. Search form Search Whole Genome Sequencing You are here Home Testing & Services Testing ... the full story, click here . What is whole genome sequencing? Whole genome sequencing is the mapping out ...

  16. The platypus genome unraveled.

    PubMed

    O'Brien, Stephen J

    2008-06-13

    The genome of the platypus has been sequenced, assembled, and annotated by an international genomics team. Like the animal itself the platypus genome contains an amalgam of mammal, reptile, and bird-like features.

  17. Genome evolution: the dynamics of static genomes.

    PubMed

    Stechmann, Alexandra

    2004-06-22

    A random survey of a microsporidian genome has revealed some striking features. Although the genomes of microsporidians are among the smallest known for eukaryotes, their organisation appears to be well conserved.

  18. Genome cartography: charting the apicomplexan genome.

    PubMed

    Kissinger, Jessica C; DeBarry, Jeremy

    2011-08-01

    Genes reside in particular genomic contexts that can be mapped at many levels. Historically, 'genetic maps' were used primarily to locate genes. Recent technological advances in the determination of genome sequences have made the analysis and comparison of whole genomes possible and increasingly tractable. What do we see if we shift our focus from gene content (the 'inventory' of genes contained within a genome) to the composition and organization of a genome? This review examines what has been learned about the evolution of the apicomplexan genome as well as the significance and impact of genomic location on our understanding of the eukaryotic genome and parasite biology. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Genomic selection requires genomic control of inbreeding.

    PubMed

    Sonesson, Anna K; Woolliams, John A; Meuwissen, Theo H E

    2012-08-16

    In the past, pedigree relationships were used to control and monitor inbreeding because genomic relationships among selection candidates were not available until recently. The aim of this study was to understand the consequences for genetic variability across the genome when genomic information is used to estimate breeding values and in managing the inbreeding generated in the course of selection on genome-enhanced estimated breeding values. These consequences were measured by genetic gain, pedigree- and genome-based rates of inbreeding, and local inbreeding across the genome. Breeding schemes were compared by simulating truncation selection or optimum contribution selection with a restriction on pedigree- or genome-based inbreeding, and with selection using estimated breeding values based on genome- or pedigree-based BLUP. Trait information was recorded on full-sibs of the candidates. When the information used to estimate breeding values and to constrain rates of inbreeding were either both pedigree-based or both genome-based, rates of genomic inbreeding were close to the desired values and the identical-by-descent profiles were reasonably uniform across the genome. However, with a pedigree-based inbreeding constraint and genome-based estimated breeding values, genomic rates of inbreeding were much higher than expected. With pedigree-instead of genome-based estimated breeding values, the impact of the largest QTL on the breeding values was much smaller, resulting in a more uniform genome-wide identical-by-descent profile but genomic rates of inbreeding were still higher than expected based on pedigree relationships, because they measure the inbreeding at a neutral locus not linked to any QTL. Neutral loci did not exist here, where there were 100 QTL on each chromosome. With a pedigree-based inbreeding constraint and genome-based estimated breeding values, genomic rates of inbreeding substantially exceeded the value of its constraint. In contrast, with a genome

  20. Plant Genome Duplication Database.

    PubMed

    Lee, Tae-Ho; Kim, Junah; Robertson, Jon S; Paterson, Andrew H

    2017-01-01

    Genome duplication, widespread in flowering plants, is a driving force in evolution. Genome alignments between/within genomes facilitate identification of homologous regions and individual genes to investigate evolutionary consequences of genome duplication. PGDD (the Plant Genome Duplication Database), a public web service database, provides intra- or interplant genome alignment information. At present, PGDD contains information for 47 plants whose genome sequences have been released. Here, we describe methods for identification and estimation of dates of genome duplication and speciation by functions of PGDD.The database is freely available at http://chibba.agtec.uga.edu/duplication/.

  1. Ensembl genomes 2016: more genomes, more complexity

    USDA-ARS?s Scientific Manuscript database

    Ensembl Genomes (http://www.ensemblgenomes.org) is an integrating resource for genome-scale data from non-vertebrate species, complementing the resources for vertebrate genomics developed in the context of the Ensembl project (http://www.ensembl.org). Together, the two resources provide a consistent...

  2. Ensembl Genomes 2016: more genomes, more complexity.

    PubMed

    Kersey, Paul Julian; Allen, James E; Armean, Irina; Boddu, Sanjay; Bolt, Bruce J; Carvalho-Silva, Denise; Christensen, Mikkel; Davis, Paul; Falin, Lee J; Grabmueller, Christoph; Humphrey, Jay; Kerhornou, Arnaud; Khobova, Julia; Aranganathan, Naveen K; Langridge, Nicholas; Lowy, Ernesto; McDowall, Mark D; Maheswari, Uma; Nuhn, Michael; Ong, Chuang Kee; Overduin, Bert; Paulini, Michael; Pedro, Helder; Perry, Emily; Spudich, Giulietta; Tapanari, Electra; Walts, Brandon; Williams, Gareth; Tello-Ruiz, Marcela; Stein, Joshua; Wei, Sharon; Ware, Doreen; Bolser, Daniel M; Howe, Kevin L; Kulesha, Eugene; Lawson, Daniel; Maslen, Gareth; Staines, Daniel M

    2016-01-04

    Ensembl Genomes (http://www.ensemblgenomes.org) is an integrating resource for genome-scale data from non-vertebrate species, complementing the resources for vertebrate genomics developed in the context of the Ensembl project (http://www.ensembl.org). Together, the two resources provide a consistent set of programmatic and interactive interfaces to a rich range of data including reference sequence, gene models, transcriptional data, genetic variation and comparative analysis. This paper provides an update to the previous publications about the resource, with a focus on recent developments. These include the development of new analyses and views to represent polyploid genomes (of which bread wheat is the primary exemplar); and the continued up-scaling of the resource, which now includes over 23 000 bacterial genomes, 400 fungal genomes and 100 protist genomes, in addition to 55 genomes from invertebrate metazoa and 39 genomes from plants. This dramatic increase in the number of included genomes is one part of a broader effort to automate the integration of archival data (genome sequence, but also associated RNA sequence data and variant calls) within the context of reference genomes and make it available through the Ensembl user interfaces.

  3. Ensembl Genomes 2016: more genomes, more complexity

    PubMed Central

    Kersey, Paul Julian; Allen, James E.; Armean, Irina; Boddu, Sanjay; Bolt, Bruce J.; Carvalho-Silva, Denise; Christensen, Mikkel; Davis, Paul; Falin, Lee J.; Grabmueller, Christoph; Humphrey, Jay; Kerhornou, Arnaud; Khobova, Julia; Aranganathan, Naveen K.; Langridge, Nicholas; Lowy, Ernesto; McDowall, Mark D.; Maheswari, Uma; Nuhn, Michael; Ong, Chuang Kee; Overduin, Bert; Paulini, Michael; Pedro, Helder; Perry, Emily; Spudich, Giulietta; Tapanari, Electra; Walts, Brandon; Williams, Gareth; Tello–Ruiz, Marcela; Stein, Joshua; Wei, Sharon; Ware, Doreen; Bolser, Daniel M.; Howe, Kevin L.; Kulesha, Eugene; Lawson, Daniel; Maslen, Gareth; Staines, Daniel M.

    2016-01-01

    Ensembl Genomes (http://www.ensemblgenomes.org) is an integrating resource for genome-scale data from non-vertebrate species, complementing the resources for vertebrate genomics developed in the context of the Ensembl project (http://www.ensembl.org). Together, the two resources provide a consistent set of programmatic and interactive interfaces to a rich range of data including reference sequence, gene models, transcriptional data, genetic variation and comparative analysis. This paper provides an update to the previous publications about the resource, with a focus on recent developments. These include the development of new analyses and views to represent polyploid genomes (of which bread wheat is the primary exemplar); and the continued up-scaling of the resource, which now includes over 23 000 bacterial genomes, 400 fungal genomes and 100 protist genomes, in addition to 55 genomes from invertebrate metazoa and 39 genomes from plants. This dramatic increase in the number of included genomes is one part of a broader effort to automate the integration of archival data (genome sequence, but also associated RNA sequence data and variant calls) within the context of reference genomes and make it available through the Ensembl user interfaces. PMID:26578574

  4. Funding Opportunity: Genomic Data Centers

    Cancer.gov

    Funding Opportunity CCG, Funding Opportunity Center for Cancer Genomics, CCG, Center for Cancer Genomics, CCG RFA, Center for cancer genomics rfa, genomic data analysis network, genomic data analysis network centers,

  5. Ontology for Genome Comparison and Genomic Rearrangements

    PubMed Central

    Flanagan, Keith; Stevens, Robert; Pocock, Matthew; Lee, Pete

    2004-01-01

    We present an ontology for describing genomes, genome comparisons, their evolution and biological function. This ontology will support the development of novel genome comparison algorithms and aid the community in discussing genomic evolution. It provides a framework for communication about comparative genomics, and a basis upon which further automated analysis can be built. The nomenclature defined by the ontology will foster clearer communication between biologists, and also standardize terms used by data publishers in the results of analysis programs. The overriding aim of this ontology is the facilitation of consistent annotation of genomes through computational methods, rather than human annotators. To this end, the ontology includes definitions that support computer analysis and automated transfer of annotations between genomes, rather than relying upon human mediation. PMID:18629137

  6. Enabling functional genomics with genome engineering.

    PubMed

    Hilton, Isaac B; Gersbach, Charles A

    2015-10-01

    Advances in genome engineering technologies have made the precise control over genome sequence and regulation possible across a variety of disciplines. These tools can expand our understanding of fundamental biological processes and create new opportunities for therapeutic designs. The rapid evolution of these methods has also catalyzed a new era of genomics that includes multiple approaches to functionally characterize and manipulate the regulation of genomic information. Here, we review the recent advances of the most widely adopted genome engineering platforms and their application to functional genomics. This includes engineered zinc finger proteins, TALEs/TALENs, and the CRISPR/Cas9 system as nucleases for genome editing, transcription factors for epigenome editing, and other emerging applications. We also present current and potential future applications of these tools, as well as their current limitations and areas for future advances. © 2015 Hilton and Gersbach; Published by Cold Spring Harbor Laboratory Press.

  7. Enabling functional genomics with genome engineering

    PubMed Central

    Hilton, Isaac B.; Gersbach, Charles A.

    2015-01-01

    Advances in genome engineering technologies have made the precise control over genome sequence and regulation possible across a variety of disciplines. These tools can expand our understanding of fundamental biological processes and create new opportunities for therapeutic designs. The rapid evolution of these methods has also catalyzed a new era of genomics that includes multiple approaches to functionally characterize and manipulate the regulation of genomic information. Here, we review the recent advances of the most widely adopted genome engineering platforms and their application to functional genomics. This includes engineered zinc finger proteins, TALEs/TALENs, and the CRISPR/Cas9 system as nucleases for genome editing, transcription factors for epigenome editing, and other emerging applications. We also present current and potential future applications of these tools, as well as their current limitations and areas for future advances. PMID:26430154

  8. Navigating yeast genome maintenance with functional genomics.

    PubMed

    Measday, Vivien; Stirling, Peter C

    2016-03-01

    Maintenance of genome integrity is a fundamental requirement of all organisms. To address this, organisms have evolved extremely faithful modes of replication, DNA repair and chromosome segregation to combat the deleterious effects of an unstable genome. Nonetheless, a small amount of genome instability is the driver of evolutionary change and adaptation, and thus a low level of instability is permitted in populations. While defects in genome maintenance almost invariably reduce fitness in the short term, they can create an environment where beneficial mutations are more likely to occur. The importance of this fact is clearest in the development of human cancer, where genome instability is a well-established enabling characteristic of carcinogenesis. This raises the crucial question: what are the cellular pathways that promote genome maintenance and what are their mechanisms? Work in model organisms, in particular the yeast Saccharomyces cerevisiae, has provided the global foundations of genome maintenance mechanisms in eukaryotes. The development of pioneering genomic tools inS. cerevisiae, such as the systematic creation of mutants in all nonessential and essential genes, has enabled whole-genome approaches to identifying genes with roles in genome maintenance. Here, we review the extensive whole-genome approaches taken in yeast, with an emphasis on functional genomic screens, to understand the genetic basis of genome instability, highlighting a range of genetic and cytological screening modalities. By revealing the biological pathways and processes regulating genome integrity, these analyses contribute to the systems-level map of the yeast cell and inform studies of human disease, especially cancer. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  9. Culex genome is not just another genome for comparative genomics.

    PubMed

    Reddy, B P Niranjan; Labbé, Pierrick; Corbel, Vincent

    2012-03-30

    Formal publication of the Culex genome sequence has closed the human disease vector triangle by meeting the Anopheles gambiae and Aedes aegypti genome sequences. Compared to these other mosquitoes, Culex quinquefasciatus possesses many specific hallmark characteristics, and may thus provide different angles for research which ultimately leads to a practical solution for controlling the ever increasing burden of insect-vector-borne diseases around the globe. We argue the special importance of the cosmopolitan species- Culex genome sequence by invoking many interesting questions and the possible of potential of the Culex genome to answer those.

  10. Culex genome is not just another genome for comparative genomics

    PubMed Central

    2012-01-01

    Formal publication of the Culex genome sequence has closed the human disease vector triangle by meeting the Anopheles gambiae and Aedes aegypti genome sequences. Compared to these other mosquitoes, Culex quinquefasciatus possesses many specific hallmark characteristics, and may thus provide different angles for research which ultimately leads to a practical solution for controlling the ever increasing burden of insect-vector-borne diseases around the globe. We argue the special importance of the cosmopolitan species- Culex genome sequence by invoking many interesting questions and the possible of potential of the Culex genome to answer those. PMID:22463777

  11. GenomeFingerprinter: the genome fingerprint and the universal genome fingerprint analysis for systematic comparative genomics.

    PubMed

    Ai, Yuncan; Ai, Hannan; Meng, Fanmei; Zhao, Lei

    2013-01-01

    No attention has been paid on comparing a set of genome sequences crossing genetic components and biological categories with far divergence over large size range. We define it as the systematic comparative genomics and aim to develop the methodology. First, we create a method, GenomeFingerprinter, to unambiguously produce a set of three-dimensional coordinates from a sequence, followed by one three-dimensional plot and six two-dimensional trajectory projections, to illustrate the genome fingerprint of a given genome sequence. Second, we develop a set of concepts and tools, and thereby establish a method called the universal genome fingerprint analysis (UGFA). Particularly, we define the total genetic component configuration (TGCC) (including chromosome, plasmid, and phage) for describing a strain as a systematic unit, the universal genome fingerprint map (UGFM) of TGCC for differentiating strains as a universal system, and the systematic comparative genomics (SCG) for comparing a set of genomes crossing genetic components and biological categories. Third, we construct a method of quantitative analysis to compare two genomes by using the outcome dataset of genome fingerprint analysis. Specifically, we define the geometric center and its geometric mean for a given genome fingerprint map, followed by the Euclidean distance, the differentiate rate, and the weighted differentiate rate to quantitatively describe the difference between two genomes of comparison. Moreover, we demonstrate the applications through case studies on various genome sequences, giving tremendous insights into the critical issues in microbial genomics and taxonomy. We have created a method, GenomeFingerprinter, for rapidly computing, geometrically visualizing, intuitively comparing a set of genomes at genome fingerprint level, and hence established a method called the universal genome fingerprint analysis, as well as developed a method of quantitative analysis of the outcome dataset. These have set

  12. GenomeFingerprinter: The Genome Fingerprint and the Universal Genome Fingerprint Analysis for Systematic Comparative Genomics

    PubMed Central

    Ai, Yuncan; Ai, Hannan; Meng, Fanmei; Zhao, Lei

    2013-01-01

    Background No attention has been paid on comparing a set of genome sequences crossing genetic components and biological categories with far divergence over large size range. We define it as the systematic comparative genomics and aim to develop the methodology. Results First, we create a method, GenomeFingerprinter, to unambiguously produce a set of three-dimensional coordinates from a sequence, followed by one three-dimensional plot and six two-dimensional trajectory projections, to illustrate the genome fingerprint of a given genome sequence. Second, we develop a set of concepts and tools, and thereby establish a method called the universal genome fingerprint analysis (UGFA). Particularly, we define the total genetic component configuration (TGCC) (including chromosome, plasmid, and phage) for describing a strain as a systematic unit, the universal genome fingerprint map (UGFM) of TGCC for differentiating strains as a universal system, and the systematic comparative genomics (SCG) for comparing a set of genomes crossing genetic components and biological categories. Third, we construct a method of quantitative analysis to compare two genomes by using the outcome dataset of genome fingerprint analysis. Specifically, we define the geometric center and its geometric mean for a given genome fingerprint map, followed by the Euclidean distance, the differentiate rate, and the weighted differentiate rate to quantitatively describe the difference between two genomes of comparison. Moreover, we demonstrate the applications through case studies on various genome sequences, giving tremendous insights into the critical issues in microbial genomics and taxonomy. Conclusions We have created a method, GenomeFingerprinter, for rapidly computing, geometrically visualizing, intuitively comparing a set of genomes at genome fingerprint level, and hence established a method called the universal genome fingerprint analysis, as well as developed a method of quantitative analysis of the

  13. Exploring Other Genomes: Bacteria.

    ERIC Educational Resources Information Center

    Flannery, Maura C.

    2001-01-01

    Points out the importance of genomes other than the human genome project and provides information on the identified bacterial genomes Pseudomonas aeuroginosa, Leprosy, Cholera, Meningitis, Tuberculosis, Bubonic Plague, and plant pathogens. Considers the computer's use in genome studies. (Contains 14 references.) (YDS)

  14. Exploring Other Genomes: Bacteria.

    ERIC Educational Resources Information Center

    Flannery, Maura C.

    2001-01-01

    Points out the importance of genomes other than the human genome project and provides information on the identified bacterial genomes Pseudomonas aeuroginosa, Leprosy, Cholera, Meningitis, Tuberculosis, Bubonic Plague, and plant pathogens. Considers the computer's use in genome studies. (Contains 14 references.) (YDS)

  15. Exploiting the Genome

    DTIC Science & Technology

    1998-09-11

    complete human genome sequence . 14. SUBJECT TERMS 15. NUMBER OF PAGES 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT Unclassified 18. SECURITY...goal of the project is to ob- tain the complete sequence of the human genome by the year 2005. The genome contains approximately 3.3 Gb (billion base...and second, to consider possible roles for the DOE in the "post- genomic " era, following acquisition of the complete human genome

  16. The kangaroo genome

    PubMed Central

    Wakefield, Matthew J.; Graves, Jennifer A. Marshall

    2003-01-01

    The kangaroo genome is a rich and unique resource for comparative genomics. Marsupial genetics and cytology have made significant contributions to the understanding of gene function and evolution, and increasing the availability of kangaroo DNA sequence information would provide these benefits on a genomic scale. Here we summarize the contributions from cytogenetic and genetic studies of marsupials, describe the genomic resources currently available and those being developed, and explore the benefits of a kangaroo genome project. PMID:12612602

  17. Genome Maps, a new generation genome browser

    PubMed Central

    Medina, Ignacio; Salavert, Francisco; Sanchez, Rubén; de Maria, Alejandro; Alonso, Roberto; Escobar, Pablo; Bleda, Marta; Dopazo, Joaquín

    2013-01-01

    Genome browsers have gained importance as more genomes and related genomic information become available. However, the increase of information brought about by new generation sequencing technologies is, at the same time, causing a subtle but continuous decrease in the efficiency of conventional genome browsers. Here, we present Genome Maps, a genome browser that implements an innovative model of data transfer and management. The program uses highly efficient technologies from the new HTML5 standard, such as scalable vector graphics, that optimize workloads at both server and client sides and ensure future scalability. Thus, data management and representation are entirely carried out by the browser, without the need of any Java Applet, Flash or other plug-in technology installation. Relevant biological data on genes, transcripts, exons, regulatory features, single-nucleotide polymorphisms, karyotype and so forth, are imported from web services and are available as tracks. In addition, several DAS servers are already included in Genome Maps. As a novelty, this web-based genome browser allows the local upload of huge genomic data files (e.g. VCF or BAM) that can be dynamically visualized in real time at the client side, thus facilitating the management of medical data affected by privacy restrictions. Finally, Genome Maps can easily be integrated in any web application by including only a few lines of code. Genome Maps is an open source collaborative initiative available in the GitHub repository (https://github.com/compbio-bigdata-viz/genome-maps). Genome Maps is available at: http://www.genomemaps.org. PMID:23748955

  18. Genome Maps, a new generation genome browser.

    PubMed

    Medina, Ignacio; Salavert, Francisco; Sanchez, Rubén; de Maria, Alejandro; Alonso, Roberto; Escobar, Pablo; Bleda, Marta; Dopazo, Joaquín

    2013-07-01

    Genome browsers have gained importance as more genomes and related genomic information become available. However, the increase of information brought about by new generation sequencing technologies is, at the same time, causing a subtle but continuous decrease in the efficiency of conventional genome browsers. Here, we present Genome Maps, a genome browser that implements an innovative model of data transfer and management. The program uses highly efficient technologies from the new HTML5 standard, such as scalable vector graphics, that optimize workloads at both server and client sides and ensure future scalability. Thus, data management and representation are entirely carried out by the browser, without the need of any Java Applet, Flash or other plug-in technology installation. Relevant biological data on genes, transcripts, exons, regulatory features, single-nucleotide polymorphisms, karyotype and so forth, are imported from web services and are available as tracks. In addition, several DAS servers are already included in Genome Maps. As a novelty, this web-based genome browser allows the local upload of huge genomic data files (e.g. VCF or BAM) that can be dynamically visualized in real time at the client side, thus facilitating the management of medical data affected by privacy restrictions. Finally, Genome Maps can easily be integrated in any web application by including only a few lines of code. Genome Maps is an open source collaborative initiative available in the GitHub repository (https://github.com/compbio-bigdata-viz/genome-maps). Genome Maps is available at: http://www.genomemaps.org.

  19. Two Host Clades, Two Bacterial Arsenals: Evolution through Gene Losses in Facultative Endosymbionts

    PubMed Central

    Rollat-Farnier, Pierre-Antoine; Santos-Garcia, Diego; Rao, Qiong; Sagot, Marie-France; Silva, Francisco J.; Henri, Hélène; Zchori-Fein, Einat; Latorre, Amparo; Moya, Andrés; Barbe, Valérie; Liu, Shu-Sheng; Wang, Xiao-Wei; Vavre, Fabrice; Mouton, Laurence

    2015-01-01

    Bacterial endosymbiosis is an important evolutionary process in insects, which can harbor both obligate and facultative symbionts. The evolution of these symbionts is driven by evolutionary convergence, and they exhibit among the tiniest genomes in prokaryotes. The large host spectrum of facultative symbionts and the high diversity of strategies they use to infect new hosts probably impact the evolution of their genome and explain why they undergo less severe genomic erosion than obligate symbionts. Candidatus Hamiltonella defensa is suitable for the investigation of the genomic evolution of facultative symbionts because the bacteria are engaged in specific relationships in two clades of insects. In aphids, H. defensa is found in several species with an intermediate prevalence and confers protection against parasitoids. In whiteflies, H. defensa is almost fixed in some species of Bemisia tabaci, which suggests an important role of and a transition toward obligate symbiosis. In this study, comparisons of the genome of H. defensa present in two B. tabaci species (Middle East Asia Minor 1 and Mediterranean) and in the aphid Acyrthosiphon pisum revealed that they belong to two distinct clades and underwent specific gene losses. In aphids, it contains highly virulent factors that could allow protection and horizontal transfers. In whiteflies, the genome lost these factors and seems to have a limited ability to acquire genes. However it contains genes that could be involved in the production of essential nutrients, which is consistent with a primordial role for this symbiont. In conclusion, although both lineages of H. defensa have mutualistic interactions with their hosts, their genomes follow distinct evolutionary trajectories that reflect their phenotype and could have important consequences on their evolvability. PMID:25714744

  20. Persistent, circulative transmission of begomoviruses by whitefly vectors

    USDA-ARS?s Scientific Manuscript database

    Begomoviruses comprise an emerging and economically important group of plant viruses exclusively transmitted by the sweetpotato whitefly Bemisia tabaci in many regions of the world. The past twenty years have witnessed significant progress in studying the molecular interactions between members of th...