Sample records for infect rice citrus

  1. Sequence analysis of three citrus viroids infecting a single Tunisian citrus tree (Citrus, reticulata, Clementine)

    E-print Network

    Perreault, Jean-Pierre

    Sequence analysis of three citrus viroids infecting a single Tunisian citrus tree (Citrus agricole, Ministère de l'Agriculture. Abstract We report the nucleotide sequences of three citrus viroids belonging to three different genera: Citrus exocortis viroid (CEVd), Hop stunt viroid (HSVd) and Citrus

  2. Transcriptional response of Citrus aurantifolia to infection by Citrus tristeza virus

    Microsoft Academic Search

    Mónica Gandía; Ana Conesa; Gema Ancillo; José Gadea; Javier Forment; Vicente Pallás; Ricardo Flores; Nuria Duran-Vila; Pedro Moreno; José Guerri

    2007-01-01

    Changes in gene expression of Mexican lime plants in response to infection with a severe (T305) or a mild (T385) isolate of Citrus tristeza virus (CTV) were analyzed using a cDNA microarray containing 12,672 probes to 6875 different citrus genes. Statistically significant (P<0.01) expression changes of 334 genes were detected in response to infection with isolate T305, whereas infection with

  3. Characterization of Citrus Tristeza Virus Subgenomic RNAs in Infected Tissue

    Microsoft Academic Search

    Mark E. Hilf; Alexander V. Karasev; Hanumantha R. Pappu; David J. Gumpf; Charles L. Niblett; Stephen M. Garnsey

    1995-01-01

    Citrus tristeza virus (CTV) specific RNAs extracted from infected citrus tissue were analyzed by Northern blot hybridization. RNAs were characterized by size and identified using cDNA probes specific to nine open reading frames (ORFs) identified by the analysis of sequence obtained from cDNA clones of the T36 isolate of CTV. Sequence specific cDNA probes identified the genomic RNA as well

  4. Factors affecting infection of citrus with Xanthomonas axonopodis pv citri.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Xanthomonas axonopodis pv citri (Xac) causes citrus canker and is now considered endemic in Florida. Factors affecting dispersal and infection of the bacteria need to be understood to help optimize disease management strategies. Wind (0-18 m/sec) was simulated outdoors using a fan to study infection...

  5. New Ceratocystis species infecting coffee, cacao, citrus and native trees in Colombia

    E-print Network

    New Ceratocystis species infecting coffee, cacao, citrus and native trees in Colombia M. Van Wyk. The aim of this study was to compare representatives of these two groups of isolates from coffee, citrus. fimbriata s.l. in Colombia is found on a wide range of hosts other than coffee. These include citrus (Citrus

  6. Identification of large masses of citrus fruit and rice fields in eastern Spain

    NASA Technical Reports Server (NTRS)

    Desagredo, F. L.; Salinas, F. G.

    1973-01-01

    ERTS-1 imagery has been successfully used for the identification of large areas of citrus groves and rice fields in the Valencia region of Eastern Spain. Results are encouraging and will facilitate the elaboration of a land use map with a fair degree of definition once methods prove to be fully operational.

  7. Natural rice rhizospheric microbes suppress rice blast infections

    PubMed Central

    2014-01-01

    Background The natural interactions between plant roots and their rhizospheric microbiome are vital to plant fitness, modulating both growth promotion and disease suppression. In rice (Oryza sativa), a globally important food crop, as much as 30% of yields are lost due to blast disease caused by fungal pathogen Magnaporthe oryzae. Capitalizing on the abilities of naturally occurring rice soil bacteria to reduce M. oryzae infections could provide a sustainable solution to reduce the amount of crops lost to blast disease. Results Naturally occurring root-associated rhizospheric bacteria were isolated from California field grown rice plants (M-104), eleven of which were taxonomically identified by16S rRNA gene sequencing and fatty acid methyl ester (FAME) analysis. Bacterial isolates were tested for biocontrol activity against the devastating foliar rice fungal pathogen, M. oryzae pathovar 70–15. In vitro, a Pseudomonas isolate, EA105, displayed antibiosis through reducing appressoria formation by nearly 90% as well as directly inhibiting fungal growth by 76%. Although hydrogen cyanide (HCN) is a volatile commonly produced by biocontrol pseudomonads, the activity of EA105 seems to be independent of its HCN production. During in planta experiments, EA105 reduced the number of blast lesions formed by 33% and Pantoea agglomerans isolate, EA106 by 46%. Our data also show both EA105 and EA106 trigger jasmonic acid (JA) and ethylene (ET) dependent induced systemic resistance (ISR) response in rice. Conclusions Out of 11 bacteria isolated from rice soil, pseudomonad EA105 most effectively inhibited the growth and appressoria formation of M. oryzae through a mechanism that is independent of cyanide production. In addition to direct antagonism, EA105 also appears to trigger ISR in rice plants through a mechanism that is dependent on JA and ET signaling, ultimately resulting in fewer blast lesions. The application of native bacteria as biocontrol agents in combination with current disease protection strategies could aid in global food security. PMID:24884531

  8. Morphological, molecular and virulence characterization of three Lencanicillium species infecting Asian citrus psyllids in Huangyan citrus groves.

    PubMed

    Lu, Lianming; Cheng, Baoping; Du, Danchao; Hu, Xiurong; Peng, Aitian; Pu, Zhanxu; Zhang, Xiaoya; Huang, Zhendong; Chen, Guoqing

    2015-02-01

    Citrus greening or Huanglongbing (HLB) is caused by the infection of Candidatus Liberibacter spp. in citrus plants. Since Asian citrus psyllid is the primary vector of this bacterial pathogen, the spread of HLB can be mitigated by suppressing Asian citrus psyllid populations in citrus groves using entomopathogens. To expand the current data on entomopathogens infecting Asian citrus psyllids, we isolated and characterized three different entomopathogens. Strains ZJLSP07, ZJLA08, and ZJLP09 infected the Asian citrus psyllid, Diaphorina citri Kuwayama, in Huangyan citrus groves. Based on molecular and morphological analyses, two were identified as Lecanicillium attenuatum and Lecanicillium psalliotae, and the third was recognized as an unidentified species of the genus, Lecanicillium. The corrected mortalities caused by strains ZJLSP07, ZJLA08 were 100% at 7days post-inoculation, while by ZJLP09 complete mortality occurred at 6days after inoculation, with 1.0×10(8)conidia/ml at 25°C and a relative humidity of 90% in the laboratory. Under the same condition, the corrected mortalities caused by strains ZJLSP07, ZJLA08 and ZJLP09 were 100%, 92.55% and 100%, respectively at 9days post-inoculation in the greenhouse. Our findings also revealed that these fungal strains infected D. citri using hyphae that penetrated deep into the insect tissues. Further, all three strains secreted the enzymes proteinases, chitinases and lipases with a potential to destroy insect tissues. Interestingly, strain ZJLP09 had an earlier invasion time and the highest levels of enzyme activities when compared to the other two strains. These findings have expanded the existing pool of entomopathogenic fungi that infect D. citri and can be potentially used for the management of D. citri populations. PMID:25593036

  9. Near-Infrared Spectroscopy for discrimination of huanglongbing-infected citrus leaves from uninfected leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus greening, also called Huanglongbing (HLB) or yellow dragon disease, is one of the more serious diseases of citrus and is a threat to the U.S. industry. An infected tree produces fruit that is unsuitable for sale as fresh fruit or for juice. The only definitive method of diagnosis of trees su...

  10. RNA Sequences Complementary to Citrus Exocortis Viroid in Nucleic Acid Preparations from Infected Gynura aurantiaca

    Microsoft Academic Search

    L. K. Grill; J. S. Semancik

    1978-01-01

    Molecular hybridization with 125I-labeled citrus exocortis viroid RNA has been used to survey nucleic acid preparations from Gynura aurantiaca for viroid complementary molecules. A differential hybridization effect was detected between nucleic acid extracts from healthy and infected tissue in which significant RNase-resistant 125I-labeled citrus exocortis viroid resulted in hybridization studies with the infected tissue extracts. Subsequent characterization indicated that RNA

  11. PURIFICATION OF VIRUS-LIKE PARTICLES FROM CITRUS CHLOROTIC DWARF INFECTED CITRUS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus chlorotic dwarf (CCD) is a new disease of citrus having been found in Turkey in the mid 1980s. Disease symptoms in the field consist of chlorotic leaf patterns, crinkling, leaf distortion, shoot malformation and stunting in young trees. CCD is vectored by the bayberry whitefly and is graft ...

  12. Citrus.

    PubMed

    Orbovi?, Vladimir; Grosser, Jude W

    2006-01-01

    Since the initial reports on production of transgenic Citrus via Agrobacterium-mediated transformation, significant progress has been made, and many steps of this procedure using the juvenile tissue explants have been improved. Abundant availability of starting material and relative simplicity make this procedure an attractive choice for many researchers despite transformation efficiency that is in the low range of about 1%. Variety of available Agrobacterium strains and reporter/selection genes further facilitate the work by allowing careful planning of experiments in which many steps can be adjusted towards a particular Citrus cultivar. With the use of this procedure, genetically transformed grapefruit, oranges, lime, and rootstock cultivars are routinely produced while some difficulties persist in efforts to transform lemon and especially mandarin cultivars. PMID:17033062

  13. Metabolomic analysis of citrus infection by Candidatus Liberibacter reveals insight into pathogenicity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB), considered the most serious citrus disease in the world, is associated with the non-culturable bacterium Candidatus Liberibacter asiaticus (Las). Infection by the pathogen leads to reduced plant vigor and productivity, and ultimately results in death of the infected tree. Additi...

  14. Infection and decontamination of citrus-canker-inoculated leaf surfaces

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (Xanthomonas citri subsp. citri, Xcc) is now considered endemic in Florida and continues to spread. Personnel and equipment decontamination is practiced in both disease-endemic and disease-free areas to reduce the risk of bacterial spread by man or machinery. We used grapefruit leaf su...

  15. Simultaneous determination of nickel, lead, zinc, and copper in citrus leaves and rice flour by liquid chromatography with hexamethylenedithiocarbamate extraction

    SciTech Connect

    Ichinoki, S.; Yamazaki, M.

    1985-10-01

    Reversed-phase liquid chromatography followed by solvent extraction with hexamethyleneammonium hexamethylenedithiocarbamate (HMA-HMDC) was carried out to determine Ni, Pb, Zn, and Cu in standard reference citrus leaves and rice flour. These samples (250 mg) were ashed with nitric acid and perchloric acid. The metals in the ash were extracted into chloroform as HMDC chelates which were then separated on a C 18 column and monitored at 260 nm. The microgram per gram levels of Ni, Pb, Zn, and Cu in the standard biological materials were simultaneously determined within 25 min. 22 references, 3 figures, 1 table.

  16. Infection of rice plants by rice black streaked dwarf virus improves an egg parasitoid, Anagrus nilaparvatae (Hymenoptera: Mymaridae), of rice planthoppers.

    PubMed

    Xu, Hongxing; He, Xiaochan; Zheng, Xusong; Yang, Yajun; Tian, Junce; Lu, Zhongxian

    2014-10-01

    The effects of rice plants infected by rice black streaked dwarf virus (RBSDV) on the host preference, duration of immature stages, sex ratio, and adult longevity and parasitic capacity of an egg parasitoid, Anagrus nilaparvatae Pang et Wang, of rice brown planthopper, Nilaparvata lugens Stål, were evaluated. Tests of response to plant volatiles using an olfactometer showed that A. nilaparvatae preferred rice plants harboring rice brown planthopper eggs over plants free of rice brown planthopper eggs. However, both the response to plant volatiles and the host selectivity test showed no significant differences in host preference between RBSDV-infected plants and healthy plants when both contained rice brown planthopper eggs. The developmental duration at immature stage of the male A. nilaparvatae in rice brown planthopper eggs on RBSDV-infected rice plants was significantly prolonged, and the parasitic capacity of rice brown planthopper eggs was significantly increased in comparison with the A. nilaparvatae parasite in rice brown planthopper eggs on healthy rice plants. There were no significant differences between RBSDV-infected rice plants and healthy rice plants in other ecological fitness parameters, including the developmental duration of female adults, female percentage, and adult longevity of A. nilaparvatae. PMID:25199055

  17. Metabolite signature of Candidatus Liberibacter asiaticus infection in two citrus varieties.

    PubMed

    Chin, Elizabeth L; Mishchuk, Darya O; Breksa, Andrew P; Slupsky, Carolyn M

    2014-07-16

    Huanglongbing (HLB), also known as Citrus Greening Disease, is caused by the bacterium 'Candidatus Liberibacter asiaticus' (CLas) and is a serious threat to the citrus industry. To understand the effect of CLas infection on the citrus metabolome, juice from healthy (n = 18), HLB-asymptomatic (n = 18), and HLB-symptomatic Hamlin (n = 18), as well as from healthy (n = 18) and HLB-symptomatic (n = 18) Valencia sweet oranges (from southern and eastern Florida) were evaluated using (1)H NMR-based metabolomics. Differences in the concentration of several metabolites including phenylalanine, histidine, limonin, and synephrine between control or asymptomatic fruit and symptomatic fruit were observed regardless of the citrus variety or location. There were no clear differences between the metabolite profiles of Hamlin fruits classified by PCR as asymptomatic and control, suggesting that some of the control fruit may have been infected. Taken together, these data indicate that infection due to CLas presents a strong metabolic response that is observed across different cultivars and regions, suggesting the potential for generation of metabolite-based biomarkers of CLas infection. PMID:24959841

  18. Spiroplasma citri Infection Affects Yield and Fruit Quality in Commercial Citrus Grove in California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The chronic effects of stubborn disease, caused by Spiroplasma citri, on citrus include stunting, abnormal fruit shape and reduced yield. However, disease impact have never been quantified in a commercial grove. The objective of this work was to measure the impact of S. citri infection on tree dev...

  19. LATENCY OF SYSTEMIC INFECTION IN YOUNG FIELD-GROWN SWEET ORANGE TREES FOLLOWING GRAFT-INOCULATION WITH CITRUS TRISTEZA VIRUS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Experiments were conducted to determine the time required for Citrus tristeza virus (CTV) to begin migration from the site of inoculation, and the subsequent incubation period required for systemic infection to occur. Young CTV-free sweet orange trees propagated on Citrus macrophylla rootstocks wer...

  20. Temporal progression of 'Candidatus Liberibacter asiaticus' infection in citrus and acquisition efficiency by Diaphorina citri.

    PubMed

    Coletta-Filho, Helvecio D; Daugherty, Matthew P; Ferreira, Cléderson; Lopes, João R S

    2014-04-01

    Over the last decade, the plant disease huanglongbing (HLB) has emerged as a primary threat to citrus production worldwide. HLB is associated with infection by phloem-limited bacteria ('Candidatus Liberibacter' spp.) that are transmitted by the Asian citrus psyllid, Diaphorina citri. Transmission efficiency varies with vector-related aspects (e.g., developmental stage and feeding periods) but there is no information on the effects of host-pathogen interactions. Here, acquisition efficiency of 'Candidatus Liberibacter asiaticus' by D. citri was evaluated in relation to temporal progression of infection and pathogen titer in citrus. We graft inoculated sweet orange trees with 'Ca. L. asiaticus'; then, at different times after inoculation, we inspected plants for HLB symptoms, measured bacterial infection levels (i.e., titer or concentration) in plants, and measured acquisition by psyllid adults that were confined on the trees. Plant infection levels increased rapidly over time, saturating at uniformly high levels (?10(8) copy number of 16S ribosomal DNA/g of plant tissue) near 200 days after inoculation-the same time at which all infected trees first showed disease symptoms. Pathogen acquisition by vectors was positively associated with plant infection level and time since inoculation, with acquisition occurring as early as the first measurement, at 60 days after inoculation. These results suggest that there is ample potential for psyllids to acquire the pathogen from trees during the asymptomatic phase of infection. If so, this could limit the effectiveness of tree rouging as a disease management tool and would likely explain the rapid spread observed for this disease in the field. PMID:24620723

  1. Transcriptional and Microscopic Analyses of Citrus Stem and Root Responses to Candidatus Liberibacter asiaticus Infection

    PubMed Central

    Aritua, Valente; Achor, Diann; Gmitter, Frederick G.; Albrigo, Gene; Wang, Nian

    2013-01-01

    Huanglongbing (HLB) is the most destructive disease that affects citrus worldwide. The disease has been associated with Candidatus Liberibacter. HLB diseased citrus plants develop a multitude of symptoms including zinc and copper deficiencies, blotchy mottle, corky veins, stunting, and twig dieback. Ca. L. asiaticus infection also seriously affects the roots. Previous study focused on gene expression of leaves and fruit to Ca. L. asiaticus infection. In this study, we compared the gene expression levels of stems and roots of healthy plants with those in Ca. L. asiaticus infected plants using microarrays. Affymetrix microarray analysis showed a total of 988 genes were significantly altered in expression, of which 885 were in the stems, and 111 in the roots. Of these, 551 and 56 were up-regulated, while 334 and 55 were down-regulated in the stem and root samples of HLB diseased trees compared to healthy plants, respectively. Dramatic differences in the transcriptional responses were observed between citrus stems and roots to Ca. L. asiaticus infection, with only 8 genes affected in both the roots and stems. The affected genes are involved in diverse cellular functions, including carbohydrate metabolism, cell wall biogenesis, biotic and abiotic stress responses, signaling and transcriptional factors, transportation, cell organization, protein modification and degradation, development, hormone signaling, metal handling, and redox. Microscopy analysis showed the depletion of starch in the roots of the infected plants but not in healthy plants. Collapse and thickening of cell walls were observed in HLB affected roots, but not as severe as in the stems. This study provides insight into the host response of the stems and roots to Ca. L. asiaticus infection. PMID:24058486

  2. Transcriptome comparison and gene coexpression network analysis provide a systems view of citrus response to ‘Candidatus Liberibacter asiaticus’ infection

    PubMed Central

    2013-01-01

    Background Huanglongbing (HLB) is arguably the most destructive disease for the citrus industry. HLB is caused by infection of the bacterium, Candidatus Liberibacter spp. Several citrus GeneChip studies have revealed thousands of genes that are up- or down-regulated by infection with Ca. Liberibacter asiaticus. However, whether and how these host genes act to protect against HLB remains poorly understood. Results As a first step towards a mechanistic view of citrus in response to the HLB bacterial infection, we performed a comparative transcriptome analysis and found that a total of 21 Probesets are commonly up-regulated by the HLB bacterial infection. In addition, a number of genes are likely regulated specifically at early, late or very late stages of the infection. Furthermore, using Pearson correlation coefficient-based gene coexpression analysis, we constructed a citrus HLB response network consisting of 3,507 Probesets and 56,287 interactions. Genes involved in carbohydrate and nitrogen metabolic processes, transport, defense, signaling and hormone response were overrepresented in the HLB response network and the subnetworks for these processes were constructed. Analysis of the defense and hormone response subnetworks indicates that hormone response is interconnected with defense response. In addition, mapping the commonly up-regulated HLB responsive genes into the HLB response network resulted in a core subnetwork where transport plays a key role in the citrus response to the HLB bacterial infection. Moreover, analysis of a phloem protein subnetwork indicates a role for this protein and zinc transporters or zinc-binding proteins in the citrus HLB defense response. Conclusion Through integrating transcriptome comparison and gene coexpression network analysis, we have provided for the first time a systems view of citrus in response to the Ca. Liberibacter spp. infection causing HLB. PMID:23324561

  3. Identification and characterization of Citrus yellow vein clearing virus, a putative new member of the genus Mandarivirus infecting Citrus spp.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Yellow vein clearing virus, an uncharacterized filamentous virus, was first observed in Pakistan in 1988 and later in India in 1997 in Etrog citron (Citrus medica). Based on electron microscopic evidence of filamentous particles, the virus, provisionally named Citrus yellow vein clearing virus (CYVC...

  4. Effect of Liberibacter infection (Huanglongbing or "greening" disease) of citrus on orange juice flavor quality by sensory evaluation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There have been some anecdotal reports that Liberibacter asiaticus [(+) Las] infection of citrus trees, recently introduced in Florida, imparts off flavor to orange juice. It is of interest to the industry to know how much Liberibacter infection affects juice quality with respect to variety, maturit...

  5. A transcriptomic approach highlights induction of secondary metabolism in citrus fruit in response to Penicillium digitatum infection

    PubMed Central

    2010-01-01

    Background Postharvest losses of citrus fruit due to green mold decay, caused by the fungus Penicillium digitaum, have a considerable economic impact. However, little is known about the molecular processes underlying the response of citrus fruit to P. digitatum. Results Here we describe the construction of a subtracted cDNA library enriched in citrus genes preferentially expressed in response to pathogen infection followed by cDNA macroarray hybridization to investigate gene expression during the early stages of colonization of the fruit's peel by P. digitatum. Sequence annotation of clones from the subtracted cDNA library revealed that induction of secondary and amino acid metabolisms constitutes the major response of citrus fruits to P. digitatum infection. Macroarray hybridization analysis was conducted with RNA from either control, wounded, ethylene treated or P. digitatum infected fruit. Results indicate an extensive overlap in the response triggered by the three treatments, but also demonstrated specific patterns of gene expression in response to each stimulus. Collectively our data indicate a significant presence of isoprenoid, alkaloid and phenylpropanoid biosynthetic genes in the transcriptomic response of citrus fruits to P. digitatum infection. About half of the genes that are up-regulated in response to pathogen infection are also induced by ethylene, but many examples of ethylene-independent gene regulation were also found. Two notable examples of this regulation pattern are the genes showing homology to a caffeine synthase and a berberine bridge enzyme, two proteins involved in alkaloid biosynthesis, which are among the most induced genes upon P. digitatum infection but are not responsive to ethylene. Conclusions This study provided the first global picture of the gene expression changes in citrus fruit in response to P. digitatum infection, emphasizing differences and commonalities with those triggered by wounding or exogenous ethylene treatment. Interpretation of the differentially expressed genes revealed that metabolism is redirected to the synthesis of isoprenes, alkaloids and phenylpropanoids. PMID:20807411

  6. Identification and molecular characterization of nuclear Citrus leprosis virus, a member of the proposed Dichorhavirus genus infecting multiple citrus species in Mexico.

    PubMed

    Roy, Avijit; Stone, Andrew L; Shao, Jonathan; Otero-Colina, Gabriel; Wei, Gang; Choudhary, Nandlal; Achor, Diann; Levy, Laurene; Nakhla, Mark K; Hartung, John S; Schneider, William; Brlansky, Ronald H

    2014-11-25

    Citrus leprosis is one of the most destructive diseases of Citrus spp., and is associated with two unrelated virus groupes that produce particles primarily in either the cytoplasm or nucleus of infected plant cells. Symptoms of leprosis, including chlorotic spots surrounded by yellow haloes on leaves and necrotic spots on twigs and fruits, were observed on leprosis-affected Mandarin and Navel navel sweet orange trees in the state of Querétaro, Mexico. Serological and molecular assays showed that the cytoplasmic types of citrus leprosis viruses (CiLV-Cs) often associated with leprosis symptomatic tissues were absent. However, using transmission electron microscopy bullet-shaped rhabdovirus-like virions were observed in the nuclei and cytoplasm of the citrus leprosis infected leaf tissues. An analysis of small RNA populations from symptomatic tissue was carried out to determine the genome sequence of the rhabdovirus-like particles observed in the citrus leprosis samples. The complete genome sequence showed that the nuclear type of CiLV (CiLV-N) present in the samples consisted of two negative sense RNAs, a 6268 nt long RNA1 and a 5847 nt long RNA2, excluding the poly(A) tails. CiLV-N had a genome organization identical to that of Orchid fleck virus (OFV) with the exception of shorter 5?-UTRs in RNA1 (53 vs 205 nt) and RNA2 (34 vs 182 nt). Phylogenetic trees constructed with the amino acid sequences of the nucleocapsid (N) and glycoproteins (G) and the RNA polymerase (L protein) showed that CiLV-N clusters with OFV. Furthermore, phylogenetic analyses of N protein established CiLV-N as a member of the unassignedproposed genus Dichorhavirus. RT-PCR primers for the detection of CiLV-N were designed based on the sequence of the N-gene and the assay was optimized and tested to detect the presence of CiLV-N in both diseased and symptom-free plants. PMID:25423071

  7. Detection and diagnosis of rice-infecting viruses

    PubMed Central

    Uehara-Ichiki, Tamaki; Shiba, Takuya; Matsukura, Keiichiro; Ueno, Takanori; Hirae, Masahiro; Sasaya, Takahide

    2013-01-01

    Rice-infecting viruses have caused serious damage to rice production in Asian, American, and African countries, where about 30 rice viruses and diseases have been reported. To control these diseases, developing accurate, quick methods to detect and diagnose the viruses in the host plants and any insect vectors of the viruses is very important. Based on an antigen–antibody reaction, serological methods such as latex agglutination reaction and enzyme-linked immunosorbent assay have advanced to detect viral particles or major proteins derived from viruses. They aid in forecasting disease and surveying disease spread and are widely used for virus detection at plant protection stations and research laboratories. From the early 2000s, based on sequence information for the target virus, several other methods such as reverse transcription-polymerase chain reaction (RT-PCR) and reverse transcription-loop-mediated isothermal amplification have been developed that are sensitive, rapid, and able to differentiate closely related viruses. Recent techniques such as real-time RT-PCR can be used to quantify the pathogen in target samples and monitor population dynamics of a virus, and metagenomic analyses using next-generation sequencing and microarrays show potential for use in the diagnosis of rice diseases. PMID:24130554

  8. Splash dispersal of Phyllosticta citricarpa conidia from infected citrus fruit.

    PubMed

    Perryman, S A M; Clark, S J; West, J S

    2014-01-01

    Rain-splash dispersal of Phyllosticta citricarpa (syn. Guignardia citricarpa) conidia (pycnidiospores) from infected oranges was studied in still air and combined with wind. High power microscopy demonstrated the presence of conidia in splash droplets from diseased oranges, which exuded conidia for over one hour during repeated wetting. The largest (5?mm) incident drops produced the highest splashes (up to 41.0?cm). A linear-by-quadratic surface model predicted highest splashes to be 41.91?cm at a horizontal distance of 25.97?cm from the target orange. Large splash droplets contained most conidia (4-5.5?mm splashes averaged 308 conidia), but were splashed <30?cm horizontal distance. Most (80-90%) splashes were <1?mm diameter but carried only 0-4 conidia per droplet. In multiple splash experiments, splashes combined to reach higher maxima (up to 61.7?cm; linear-by-quadratic surface model prediction, 62.1?cm) than in the single splash experiments. In combination with wind, higher wind speeds carried an increasing proportion of splashes downwind travelling horizontally at least 8?m at the highest wind speed tested (7?m/s), due to a small proportion of droplets (<1?mm) being aerosolised. These experiments suggest that P. citricarpa conidia can be dispersed from infected oranges by splashes of water in rainfall events. PMID:25298272

  9. Splash dispersal of Phyllosticta citricarpa conidia from infected citrus fruit

    PubMed Central

    Perryman, S. A. M.; Clark, S. J.; West, J. S.

    2014-01-01

    Rain-splash dispersal of Phyllosticta citricarpa (syn. Guignardia citricarpa) conidia (pycnidiospores) from infected oranges was studied in still air and combined with wind. High power microscopy demonstrated the presence of conidia in splash droplets from diseased oranges, which exuded conidia for over one hour during repeated wetting. The largest (5?mm) incident drops produced the highest splashes (up to 41.0?cm). A linear-by-quadratic surface model predicted highest splashes to be 41.91?cm at a horizontal distance of 25.97?cm from the target orange. Large splash droplets contained most conidia (4–5.5?mm splashes averaged 308 conidia), but were splashed <30?cm horizontal distance. Most (80–90%) splashes were <1?mm diameter but carried only 0–4 conidia per droplet. In multiple splash experiments, splashes combined to reach higher maxima (up to 61.7?cm; linear-by-quadratic surface model prediction, 62.1?cm) than in the single splash experiments. In combination with wind, higher wind speeds carried an increasing proportion of splashes downwind travelling horizontally at least 8?m at the highest wind speed tested (7?m/s), due to a small proportion of droplets (<1?mm) being aerosolised. These experiments suggest that P. citricarpa conidia can be dispersed from infected oranges by splashes of water in rainfall events. PMID:25298272

  10. Global gene expression of Poncirus trifoliata, Citrus sunki and their hybrids under infection of Phytophthora parasitica

    PubMed Central

    2011-01-01

    Background Gummosis and root rot caused by Phytophthora are among the most economically important diseases in citrus. Four F1 resistant hybrids (Pool R), and four F1 susceptible hybrids (Pool S) to P. parasitica, were selected from a cross between susceptible Citrus sunki and resistant Poncirus trifoliata cv. Rubidoux. We investigated gene expression in pools of four resistant and four susceptible hybrids in comparison with their parents 48 hours after P. parasitica inoculation. We proposed that genes differentially expressed between resistant and susceptible parents and between their resistant and susceptible hybrids provide promising candidates for identifying transcripts involved in disease resistance. A microarray containing 62,876 UniGene transcripts selected from the CitEST database and prepared by NimbleGen Systems was used for analyzing global gene expression 48 hours after infection with P. parasitica. Results Three pairs of data comparisons (P. trifoliata/C. sunki, Pool R/C. sunki and Pool R/Pool S) were performed. With a filter of false-discovery rate less than 0.05 and fold change greater than 3.0, 21 UniGene transcripts common to the three pairwise comparative were found to be up-regulated, and 3 UniGene transcripts were down-regulated. Among them, our results indicated that the selected transcripts were probably involved in the whole process of plant defense responses to pathogen attack, including transcriptional regulation, signaling, activation of defense genes participating in HR, single dominant genes (R gene) such as TIR-NBS-LRR and RPS4 and switch of defense-related metabolism pathway. Differentially expressed genes were validated by RT-qPCR in susceptible and resistant plants and between inoculated and uninoculated control plants Conclusions Twenty four UniGene transcripts were identified as candidate genes for Citrus response to P. parasitica. UniGene transcripts were likely to be involved in disease resistance, such as genes potentially involved in secondary metabolite synthesis, intracellular osmotic adjustment, signal transduction pathways of cell death, oxidative burst and defense gene expression. Furthermore, our microarray data suggest another type of resistance in Citrus-Phytophthora interaction conferred by single dominant genes (R gene) since we encountered two previously reported R genes (TIR-NBS-LRR and RPS4) upregulated in the resistant genotypes relative to susceptible. We identified 7 transcripts with homology in other plants but yet unclear functional characterization which are an interesting pool for further analyses and 3 transcripts where no significant similarity was found. This is the first microarray study addressing an evaluation of transcriptional changes in response to P. parasitica in Citrus. PMID:21241495

  11. Kernel infection of Bluebonnet 50 rice by Helminthosporium oryzae and its effect on yield and quality

    E-print Network

    Fazli, Syed Fazal Imam

    1964-01-01

    noculatiot at different stages of kernel maturity . , 31 LIST QF FIGURES Figure Page Discolored and r, ormal kernels of Bluebonnet 50 arid Belle Patna rice varieties, showing dis- coloration of kernels oy Helminthos orium ~or zae 22 2, Photomicrograph... oryzae 2k CHAPTER I INTRODUCTION Infection of' rice grains by Helminthos orium ~or zae reduces the market value by causing discolored hulls and kernels. Infected kernels are also a primary source of inoculum f' or the leaf spo+ disease of rice...

  12. Wolbachia infection density in populations of the Asian citrus psyllid (Hemiptera: Liviidae).

    PubMed

    Hoffmann, M; Coy, M R; Kingdom Gibbard, H N; Pelz-Stelinski, K S

    2014-10-01

    The symbiotic relationships between bacteria of the genus Wolbachia (order Rickettsiales) and their arthropod hosts are diverse and can range from mutualism to parasitism. Whereas effects of Wolbachia on host biology are well investigated, little is known about diversity and abundance of Wolbachia in their natural hosts. The phloem-feeding Asian citrus psyllid, Diaphorina citri (Kuwayama) (Hemiptera: Liviidae), is naturally infected with Wolbachia (wDi). In the current study, we calculated the within-host density of Wolbachia in Florida D. citri populations using quantitative polymerase chain reaction for detection of the Wolbachia outer surface protein gene, wsp. Gene quantities were normalized to the D. citri wingless gene (Wg) to estimate Wolbachia abundance in individual D. citri. Using this method, significant geographic differences in Wolbachia densities were detected among Florida D. citri populations, with higher infection levels occurring in male versus female hosts. PMID:25259690

  13. The effects of ‘Candidatus Liberibacter asiaticus’ infection on the protein expression profiles and nutrient status of Citrus plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is a destructive disease of citrus plants causing significant yield loss within 4-6 years of initial infection. The etiology of HLB worldwide is associated with three insect-transmissible phloem-limited members of the bacterial group ‘Candidatus Liberibacter spp’, prevalently ‘Ca...

  14. PHENYLACETALDEHYDE O-METHYLOXIME: A VOLATILE COMPOUND FROM PLANTS INFECTED WITH CITRUS CANKER PATHOGENIC BACTERIUM, XANTHOMONAS AXONOPODIS PV. CITRI.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An aldehyde oxime o-methyl ether, phenylacetaldehyde o-methyloxime (PAAMO), was detected using solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) in the headspace above grapefruit leaves infected with Xanthomonas axonopodis pv. citri, the causal agent of citrus bacte...

  15. First Report of Dodder Transmission of Huanglongbing from Naturally Infected Murraya paniculata to Citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) or “greening” disease of citrus is caused by phloem-limited, uncultured bacteria in the genus “Candidatus Liberibacter”. HLB is one of the most destructive diseases of citrus worldwide and is considered so dangerous to a U.S. citrus production that the USDA has listed “Ca. Liberi...

  16. Expression profiling of common and specific defense responses of rice to Magnaporthe oryzae infection using deep sequencing technologies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice blast caused by Magnaporthe oryzae is a serious disease in rice production. Wild type Nipponbare and transgenic rice plants (carrying the Pi9 blast resistance gene) were challenged with the rice blast strain KJ201 to identify the early, mid and late host responses to M. oryzae infection at the ...

  17. Biological Effects of Weak Electromagnetic Field on Healthy and Infected Lime (Citrus aurantifolia) Trees with Phytoplasma

    PubMed Central

    Abdollahi, Fatemeh; Niknam, Vahid; Ghanati, Faezeh; Masroor, Faribors; Noorbakhsh, Seyyed Nasr

    2012-01-01

    Exposure to electromagnetic fields (EMF) has become an issue of concern for a great many people and is an active area of research. Phytoplasmas, also known as mycoplasma-like organisms, are wall-less prokaryotes that are pathogens of many plant species throughout the world. Effects of electromagnetic fields on the changes of lipid peroxidation, content of H2O2, proline, protein, and carbohydrates were investigated in leaves of two-year-old trees of lime (Citrus aurantifolia) infected by the Candidatus Phytoplasma aurantifoliae. The healthy and infected plants were discontinuously exposed to a 10?KHz quadratic EMF with maximum power of 9?W for 5 days, each?5 h, at 25°C. Fresh and dry weight of leaves, content of MDA, proline, and protein increased in both healthy and infected plants under electromagnetic fields, compared with those of the control plants. Electromagnetic fields decreased hydrogen peroxide and carbohydrates content in both healthy and infected plants compared to those of the controls. PMID:22649313

  18. Rice-based oral antibody fragment prophylaxis and therapy against rotavirus infection

    PubMed Central

    Tokuhara, Daisuke; ?lvarez, Beatriz; Mejima, Mio; Hiroiwa, Tomoko; Takahashi, Yuko; Kurokawa, Shiho; Kuroda, Masaharu; Oyama, Masaaki; Kozuka-Hata, Hiroko; Nochi, Tomonori; Sagara, Hiroshi; Aladin, Farah; Marcotte, Harold; Frenken, Leon G.J.; Iturriza-Gómara, Miren; Kiyono, Hiroshi; Hammarström, Lennart; Yuki, Yoshikazu

    2013-01-01

    Rotavirus-induced diarrhea is a life-threatening disease in immunocompromised individuals and in children in developing countries. We have developed a system for prophylaxis and therapy against rotavirus disease using transgenic rice expressing the neutralizing variable domain of a rotavirus-specific llama heavy-chain antibody fragment (MucoRice-ARP1). MucoRice-ARP1 was produced at high levels in rice seeds using an overexpression system and RNAi technology to suppress the production of major rice endogenous storage proteins. Orally administered MucoRice-ARP1 markedly decreased the viral load in immunocompetent and immunodeficient mice. The antibody retained in vitro neutralizing activity after long-term storage (>1 yr) and boiling and conferred protection in mice even after heat treatment at 94°C for 30 minutes. High-yield, water-soluble, and purification-free MucoRice-ARP1 thus forms the basis for orally administered prophylaxis and therapy against rotavirus infections. PMID:23925294

  19. Germination and infectivity of microconidia in the rice blast fungus Magnaporthe oryzae

    PubMed Central

    Zhang, Huili; Wu, Zhongshou; Wang, Chenfang; Li, Yang; Xu, Jin-Rong

    2014-01-01

    The rice blast fungus Magnaporthe oryzae is a model for studying fungal–plant interactions. Although it produces two types of spores (microconidia and macroconidia), previous infection studies have exclusively dealt with macroconidia. Germination of microconidia has not been reported, and their role in plant infection is not defined. Here we show that approximately 10% of microconidia germinate on plant surfaces, and that colonies derived from germinated microconidia are normal in growth and pathogenesis. In infection assays with rice and barley seedlings, microconidia fail to infect intact plants, but they can colonize and develop necrotic lesions on wounded leaves and stems. Microconidia also cause disease symptoms on inoculated spikelets in infection assays with barley and Brachypodium heads. Furthermore, microconidia are detected inside rice plants that developed blast lesions under laboratory or field conditions. Therefore, microconidia can germinate and are infectious, and may be an important factor in the rice blast cycle. PMID:25082370

  20. Polyamines in plants infected by citrus exocortis viroid or treated with silver ions and ethephon.

    PubMed

    Bellés, J M; Carbonell, J; Conejero, V

    1991-08-01

    The levels of polyamines in leaves of Gynura aurantiaca DC and tomato, Lycopersicon esculentum Mill. cv Rutgers, infected with citrus exocortis viroid (CEVd) or treated with silver nitrate or ethephon (2-chloroethylphosphonic acid) were measured by HPLC in relation to development of symptoms. Previously it had been demonstrated that treatment of G. aurantiaca plants with silver nitrate or ethephon closely mimicked the effects of viroid infection in the plants. In the studies reported here, a marked decrease in putrescine level was observed in plants infected by CEVd or treated with silver ions or ethephon. There was no significant change in either spermidine or spermine levels. Treatment of G. aurantiaca plants with specific inhibitors of ethylene biosynthesis (aminoethoxyvinylglycine, Co(2+)) or ethylene action (norbornadiene) prevented the decrease of putrescine associated with silver nitrate treatment and had no effect on spermidine or spermine levels. The development of viroid-like symptoms, the production of associated pathogenesis-related proteins, and the rise in protease activity induced by silver nitrate, were all suppressed by exogenous application of putrescine. The decreased level of putrescine as an ethylene-mediated step in the transduction of the viroid and silver or ethephon signaling is discussed. PMID:16668297

  1. RL-SAGE and microarray analysis of the rice defense transcriptome after Rhizoctonia solani infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheath blight caused by the fungal pathogen Rhizoctonia solani is an emerging problem in rice production worldwide. To elucidate the molecular basis of rice defense to the pathogen, RNA isolated from R. solani-infected leaves of Jasmine 85 was used for both RL-SAGE library construction and microarra...

  2. Possible Contribution of Blast Spores to the Oxidative Burst in the Infection Droplet on Rice Leaf

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The infection-induced overproduction of reactive oxygen species (ROS) in resistant plants is usually ascribed to the host. Here we tested the possible contribution of the parasite, the rice blast fungus to ROS production. Droplets of spore suspensions or water were kept on rice leaves or on plastic....

  3. Type IV Secretion System Is Not Involved in Infection Process in Citrus

    PubMed Central

    Jacob, Tiago Rinaldi; de Laia, Marcelo Luiz; Moreira, Leandro Marcio; Gonçalves, Janaína Fernandes; Carvalho, Flavia Maria de Souza; Ferro, Maria Inês Tiraboschi; Ferro, Jesus Aparecido

    2014-01-01

    The type IV secretion system (T4SS) is used by Gram-negative bacteria to translocate protein and DNA substrates across the cell envelope and into target cells. Xanthomonas citri subsp. citri contains two copies of the T4SS, one in the chromosome and the other is plasmid-encoded. To understand the conditions that induce expression of the T4SS in Xcc, we analyzed, in vitro and in planta, the expression of 18 ORFs from the T4SS and 7 hypothetical flanking genes by RT-qPCR. As a positive control, we also evaluated the expression of 29 ORFs from the type III secretion system (T3SS), since these genes are known to be expressed during plant infection condition, but not necessarily in standard culture medium. From the 29 T3SS genes analyzed by qPCR, only hrpA was downregulated at 72?h after inoculation. All genes associated with the T4SS were downregulated on Citrus leaves 72?h after inoculation. Our results showed that unlike the T3SS, the T4SS is not induced during the infection process. PMID:24707292

  4. Type IV Secretion System Is Not Involved in Infection Process in Citrus.

    PubMed

    Jacob, Tiago Rinaldi; de Laia, Marcelo Luiz; Moreira, Leandro Marcio; Gonçalves, Janaína Fernandes; Carvalho, Flavia Maria de Souza; Ferro, Maria Inês Tiraboschi; Ferro, Jesus Aparecido

    2014-01-01

    The type IV secretion system (T4SS) is used by Gram-negative bacteria to translocate protein and DNA substrates across the cell envelope and into target cells. Xanthomonas citri subsp. citri contains two copies of the T4SS, one in the chromosome and the other is plasmid-encoded. To understand the conditions that induce expression of the T4SS in Xcc, we analyzed, in vitro and in planta, the expression of 18 ORFs from the T4SS and 7 hypothetical flanking genes by RT-qPCR. As a positive control, we also evaluated the expression of 29 ORFs from the type III secretion system (T3SS), since these genes are known to be expressed during plant infection condition, but not necessarily in standard culture medium. From the 29 T3SS genes analyzed by qPCR, only hrpA was downregulated at 72?h after inoculation. All genes associated with the T4SS were downregulated on Citrus leaves 72?h after inoculation. Our results showed that unlike the T3SS, the T4SS is not induced during the infection process. PMID:24707292

  5. Stem pitting Citrus tristeza virus predominantly transmitted by the brown citrus aphid from mixed infections containing non-stem pitting and stem pitting isolates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus tristeza virus (CTV) is a phloem-limited closterovirus that produces a variety of symptoms in various Citrus spp. One of these symptoms is stem pitting (SP). SP does not occur in all Citrus spp. but when it does it may cause low tree vigor, decline and an economically-significant reduction ...

  6. Entomopathogenic fungi infecting the Asian citrus psyllid, Diaphorina citri (Homoptera: Psyllidae), in Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid, Diaphorina citri is an invasive pest that vectors citrus greening disease. In 2005-2006 mycosed psyllids displaying two phenotypes were collected in central Florida. The major pathogen, identified by morphological and genetic analyses, was a novel isolate related to Hirsute...

  7. Study on Citrus Response to Huanglongbing Highlights a Down-Regulation of Defense-Related Proteins in Lemon Plants Upon ‘Ca. Liberibacter asiaticus’ Infection

    PubMed Central

    Nwugo, Chika C.; Duan, Yongping; Lin, Hong

    2013-01-01

    Citrus huanglongbing (HLB) is a highly destructive disease of citrus presumably caused by ‘Candidatus Liberibacter asiaticus’ (Las), a gram-negative, insect-transmitted, phloem-limited ?-proteobacterium. Although almost all citrus plants are susceptible to HLB, reports have shown reduced susceptibility to Las infection in lemon (Citruslimon) plants. The aim of this study is to identify intra-species specific molecular mechanisms associated with Las-induced responses in lemon plants. To achieve this, comparative 2-DE and mass spectrometry, in addition to Inductively Coupled Plasma Spectroscopy (ICPS) analyses, were applied to investigate differences in protein accumulation and the concentrations of cationic elements in leaves of healthy and Las-infected lemon plants. Results showed a differential accumulation of 27 proteins, including an increase in accumulation of starch synthase but decrease in the production of photosynthesis-related proteins in Las-infected lemon plants compared to healthy plants. Furthermore, there was a 6% increase (P > 0.05) in K concentration in leaves of lemon plants upon Las infection, which support results from previous studies and might represent a common response pattern of citrus plants to Las infection. Interestingly, contrary to reports from prior studies, this study showed a general reduction in the production of defense-related pathogen-response proteins but a 128% increase in Zn concentration in lemon plants in response to Las infection. Taken together, this study sheds light on general and intra-species specific responses associated with the response of citrus plants to Las. PMID:23922636

  8. Transmission of Rice stripe virus acquired from frozen infected leaves by the small brown planthopper (Laodelphax striatellus Fallen).

    PubMed

    Zhang, Shixian; Li, Li; Wang, Xifeng; Zhou, Guanghe

    2007-12-01

    Rice stripe disease, caused by Rice stripe virus (RSV), is one of the most serious rice diseases in temperate and subtropical regions of the world. Since RSV is not transmissible mechanically, an insect transmission test was the original basis for identification of the viral population and cultivar resistance. A simple, rapid and reliable method is described by which virus-free small brown planthoppers acquired RSV from frozen infected rice leaves and transmitted the virus to healthy rice plants. Of 30 planthoppers tested, 9 insects fed on the frozen infected leaves acquired the virus as shown by an indirect-ELISA. In the transmission tests with a single insect, fed previously on frozen leaves, 5 of 30 plants (16.67%) became infected, compared to 7 of 30 plants (23.33%) became infected when a single insect fed on fresh infected leaves. All rice plants expressing stripe symptoms were identified with the virus by RT-PCR. PMID:17614147

  9. Observations on the Foliar Nematode, Aphelenchoides besseyi, Infecting Tuberose and Rice in India.

    PubMed

    Khan, Matiyar R; Handoo, Zafar A; Rao, Uma; Rao, S B; Prasad, J S

    2012-12-01

    The foliar nematode Aphelenchoides besseyi causes white tip disease in rice (Oryza sativa L.) and floral malady in tuberose (Polianthes tuberosa L.). This nematode is widely distributed in the rice fields of many states of India, including West Bengal (WB), Andhra Pradesh (AP), Madhya Pradesh (MP) and Gujarat (GT). In order to generate information on intraspecific variations of A. besseyi as well as to confirm the identity of the nematode species infecting these important crops, morphological observation was undertaken of A. besseyi isolated from tuberose and rice from WB and rice from AP, MP and GT. The molecular study was only done for rice and tuberose populations from AP and WB. The variations were observed among the populations in the tail, esophageal and anterior regions, including the occurrence of four as well as six lateral lines in the lateral fields. The morphometrics of observed populations showed variations and those could be regarded as a consequence of host-induced or geographical variations. PCR amplification of the rDNA ITS 1 and 2 region of rice (AP) and tuberose (WB) populations of A. besseyi generated one fragment of approximately 830 bp, and the size of the ITS region was 788 bp and 791 bp for tuberose and rice population, respectively. Alignment of the two sequences showed almost 100% similarity. Blast analysis revealed a very high level of similarity of both the Indian strains to a Russian population. The Indian and Russian strains could be differentiated using restriction enzyme Bccl. Host tests revealed that rice (cv. IET 4094), oat (cv. OS-6) and teosinte (cv. TL-1) showed a typical distortion due to the infection of A. besseyi. Five germplasm lines of oat showed no infection of the nematode under field conditions. Local cultivars of onion, maize, chrysanthemum, gladiolus, and Sorghum halepense were also not infected by A. besseyi. PMID:23482906

  10. Lack of effect of feeding citrus by-products in reducing salmonella in experimentally infected weanling pigs.

    PubMed

    Farrow, R L; Edrington, T S; Krueger, N A; Genovese, K J; Callaway, T R; Anderson, R C; Nisbet, D J

    2012-03-01

    The objective of the current research was to determine if feeding the citrus by-products(D) -limonene (DL) and citrus molasses would reduce the concentration and prevalence of Salmonella in weanling pigs experimentally infected with Salmonella Typhimurium. Twenty crossbred weanling pigs (average body weight [BW], 19.9 kg) were randomly assigned to one of four treatments: control, low-dose DL (1.5 ml/kg of BW per day), high-dose DL (3.0 ml/kg of BW per day), and citrus molasses (0.05 kg/kg of BW per day). Treatments were administered in the feed (twice daily) for 7 days, with one-half of the dose administered at each feeding. Fecal samples were collected twice daily (prior to administration of treatment) and cultured for quantitative and qualitative determination of the challenge strain of Salmonella. Upon termination of the study, pigs were euthanized and tissues from the stomach, ileum, cecum, spiral colon, and rectum, as well as luminal contents, were collected. In addition, the popliteal and ileocecal lymph nodes and liver, spleen, and tonsil tissue were collected for qualitative Salmonella culture. No significant treatment differences (P > 0.05) were observed among treatments for fecal concentration or prevalence of Salmonella throughout the 7-day collection period. Likewise, no treatment differences (P > 0.05) were observed for any of the tissue or luminal content samples collected. Salmonella was not cultured from the muscle-bound popliteal lymph node but was cultured from the mesenteric ileocecal lymph nodes. While there were no effects in the current experiment, future research may examine the effect of a lower challenge dose and/or different administration (dose or duration) of the citrus by-products. PMID:22410233

  11. Deciphering the Bacterial Microbiome of Citrus Plants in Response to ‘Candidatus Liberibacter asiaticus’-Infection and Antibiotic Treatments

    PubMed Central

    Zhang, Muqing; Powell, Charles A.; Benyon, Lesley S.; Zhou, Hui; Duan, Yongping

    2013-01-01

    The bacterial microbiomes of citrus plants were characterized in response to ‘Candidatus Liberibacter asiaticus’ (Las)-infection and treatments with ampicillin (Amp) and gentamicin (Gm) by Phylochip-based metagenomics. The results revealed that 7,407 of over 50,000 known Operational Taxonomic Units (OTUs) in 53 phyla were detected in citrus leaf midribs using the PhyloChip™ G3 array, of which five phyla were dominant, Proteobacteria (38.7%), Firmicutes (29.0%), Actinobacteria (16.1%), Bacteroidetes (6.2%) and Cyanobacteria (2.3%). The OTU62806, representing ‘Candidatus Liberibacter’, was present with a high titer in the plants graft-inoculated with Las-infected scions treated with Gm at 100 mg/L and in the water-treated control (CK1). However, the Las bacterium was not detected in the plants graft-inoculated with Las-infected scions treated with Amp at 1.0 g/L or in plants graft-inoculated with Las-free scions (CK2). The PhyloChip array demonstrated that more OTUs, at a higher abundance, were detected in the Gm-treated plants than in the other treatment and the controls. Pairwise comparisons indicated that 23 OTUs from the Achromobacter spp. and 12 OTUs from the Methylobacterium spp. were more abundant in CK2 and CK1, respectively. Ten abundant OTUs from the Stenotrophomonas spp. were detected only in the Amp-treatment. These results provide new insights into microbial communities that may be associated with the progression of citrus huanglongbing (HLB) and the potential effects of antibiotics on the disease and microbial ecology. PMID:24250784

  12. Caripyrin, a new inhibitor of infection-related morphogenesis in the rice blast fungus Magnaporthe oryzae.

    PubMed

    Rieger, Patrick H; Liermann, Johannes C; Opatz, Till; Anke, Heidrun; Thines, Eckhard

    2010-06-01

    Caripyrin (trans-5-(3-methyloxiranyl)pyridincarboxylic acid methyl ester, 1), a new pyridyloxirane, was isolated from submerged cultures of the basidiomycete Caripia montagnei. The compound was found to inhibit conidial germination and appressorium formation in the rice blast fungus Magnaporthe oryzae, whereas the infection-related morphogenesis in several other phytopathogenic fungi was not affected. In plant assays on rice, 1 was found to protect plants more efficiently against fungal infection than the structurally related fungal secondary metabolite, fusaric acid. Contrary to the latter, 1 was neither cytotoxic, antibacterial, nor nematicidal. PMID:20379215

  13. Southern rice black-streaked dwarf virus alters insect vectors' host orientation preferences to enhance spread and increase rice ragged stunt virus co-infection.

    PubMed

    Wang, Han; Xu, Donglin; Pu, Lingling; Zhou, Guohui

    2014-02-01

    In recent years, Southern rice black-streaked dwarf virus (SRBSDV), a tentative species in the genus Fijivirus (family Reoviridae), has spread rapidly and caused serious rice losses in eastern and southeastern Asia. With this virus spread, Rice ragged stunt virus (RRSV, genus Oryzavirus, family Reoviridae) became more common in southern China, usually in co-infection with the former. SRBSDV and RRSV are transmitted by two different species of planthoppers, white-backed planthopper (WBPH, Sogatella furcifera) and brown planthopper (BPH, Nilaparvata lugens), respectively, in a persistent, circulative, propagative manner. In this study, using a Y-shape olfactometer-based device, we tested the host preference of three types of macropterous WBPH adults for healthy or SRBSDV-infected rice plants. The results showed that virus-free WBPHs significantly preferred infected rice plants to healthy plants, whereas both the viruliferous and nonviruliferous WBPHs preferred healthy plants to infected plants. In additional tests, we found that the BPHs significantly preferred healthy plants when they were virus free, whereas RRSV-carrying BPHs preferred SRBSDV-infected rice plants. From these findings, we propose that plant viruses may alter host selection preference of vectors to enhance their spread and that of insects vectoring another virus to result in co-infection with more than one virus. PMID:24047253

  14. Processes involved in the dispersal of Xanthomonas citri pv. citri from canker-infectd citrus canopies, and in the infection of citrus foliage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (Xanthomonas citri subsp. citri, Xcc) is now considered endemic in Florida, and epidemics result in yield loss and market penalties both in Florida, and elsewhere where the pathogen occurs, and susceptible citrus is cultivated. The bacterium is dispersed in rain splash, and storms wit...

  15. Transcriptome Analysis of Early Responsive Genes in Rice during Magnaporthe oryzae Infection

    PubMed Central

    Wang, Yiming; Kwon, Soon Jae; Wu, Jingni; Choi, Jaeyoung; Lee, Yong-Hwan; Agrawal, Ganesh Kumar; Tamogami, Shigeru; Rakwal, Randeep; Park, Sang-Ryeol; Kim, Beom-Gi; Jung, Ki-Hong; Kang, Kyu Young; Kim, Sang Gon; Kim, Sun Tae

    2014-01-01

    Rice blast disease caused by Magnaporthe oryzae is one of the most serious diseases of cultivated rice (Oryza sativa L.) in most rice-growing regions of the world. In order to investigate early response genes in rice, we utilized the transcriptome analysis approach using a 300 K tilling microarray to rice leaves infected with compatible and incompatible M. oryzae strains. Prior to the microarray experiment, total RNA was validated by measuring the differential expression of rice defense-related marker genes (chitinase 2, barwin, PBZ1, and PR-10) by RT-PCR, and phytoalexins (sakuranetin and momilactone A) with HPLC. Microarray analysis revealed that 231 genes were up-regulated (>2 fold change, p < 0.05) in the incompatible interaction compared to the compatible one. Highly expressed genes were functionally characterized into metabolic processes and oxidation-reduction categories. The oxidative stress response was induced in both early and later infection stages. Biotic stress overview from MapMan analysis revealed that the phytohormone ethylene as well as signaling molecules jasmonic acid and salicylic acid is important for defense gene regulation. WRKY and Myb transcription factors were also involved in signal transduction processes. Additionally, receptor-like kinases were more likely associated with the defense response, and their expression patterns were validated by RT-PCR. Our results suggest that candidate genes, including receptor-like protein kinases, may play a key role in disease resistance against M. oryzae attack. PMID:25506299

  16. Systemic Suppression of the Shoot Metabolism upon Rice Root Nematode Infection

    PubMed Central

    Kyndt, Tina; Denil, Simon; Bauters, Lander; Van Criekinge, Wim; De Meyer, Tim

    2014-01-01

    Hirschmanniella oryzae is the most common plant-parasitic nematode in flooded rice cultivation systems. These migratory animals penetrate the plant roots and feed on the root cells, creating large cavities, extensive root necrosis and rotting. The objective of this study was to investigate the systemic response of the rice plant upon root infection by this nematode. RNA sequencing was applied on the above-ground parts of the rice plants at 3 and 7 days post inoculation. The data revealed significant modifications in the primary metabolism of the plant shoot, with a general suppression of for instance chlorophyll biosynthesis, the brassinosteroid pathway, and amino acid production. In the secondary metabolism, we detected a repression of the isoprenoid and shikimate pathways. These molecular changes can have dramatic consequences for the growth and yield of the rice plants, and could potentially change their susceptibility to above-ground pathogens and pests. PMID:25216177

  17. Incidence of Candidatus Liberibacter asiaticus infection in abandoned citrus occurring in proximity to commercially managed groves.

    PubMed

    Tiwari, Siddharth; Lewis-Rosenblum, Hannah; Pelz-Stelinski, Kirsten; Stelinski, Lukasz L

    2010-12-01

    Huanglongbing is one of the most devastating diseases of citrus (Citrus spp.). One management tactic against huanglongbing is aggressive management of the vector, the Asian citrus psyllid (Diaphorina citri Kuwayama), with insecticide applications. However, D. citri in abandoned groves are not controlled and therefore pose a risk of reinfestation for nearby commercial citrus. These abandoned groves could serve as a reservoir for the vector, as well as a source of the presumed causal agent for huanglongbing in Florida, Candidatus Liberibacter asiaticus (Las). The current study was conducted to determine the degree to which Las is present in abandoned Florida citrus groves and to compare relative inoculum levels in nearby managed and abandoned groves during times of the year when D. citri are abundant (June, July, and August). In addition, the movement of Las by dispersing D. citri adults from inner and edge rows of abandoned grove plots to the corresponding rows of managed plots was quantified during the same 3 mo. The results of the current study confirmed the presence of Las in both D. citri and plant tissue in abandoned groves at statistically equivalent levels to those in nearby managed groves. The mean number of D. citri adults dispersing from abandoned to managed grove plots ranged from 7.25 +/- 1.70 to 70.25 +/- 21.25 per 4-d intervals. Of those, the mean number of dispersing D. citri adults that were carrying the Las pathogen ranged from 1.00 +/- 0.58 to 1.50 +/- 0.50. Our results indicate that abandoned citrus groves are a significant source of Ca. Las and that dispersing D. citri move this pathogen into nearby managed groves. PMID:21309215

  18. G Protein Regulation of Disease Resistance During Infection of Rice with Rice Blast Fungus

    NSDL National Science Digital Library

    Sarah M. Assmann (Penn State University; Biology Department REV)

    2005-11-15

    When the effects of specific pathogen-produced elicitor compounds on plant cells are recognized by specific plant resistance (R) gene products, a local defense response called the hypersensitive response is triggered. Production of reactive oxygen species (ROS) and induction of defense genes are components of this response. In rice cultivars harboring null mutations in the G protein ? subunit, RGA1, ROS production and defense gene induction by the rice blast fungus Magnaporthe grisea and its sphingolipid elicitors are reduced or delayed. These results implicate heterotrimeric guanine nucleotide–binding proteins (G proteins) as important players in plant pathogen response.

  19. Low risk for helminth infection in wastewater-fed rice cultivation in Vietnam

    Microsoft Academic Search

    Do Thuy Trang; Wim van der Hoek; Phung Dac Cam; Khuong Thanh Vinh; Nguyen Van Hoa; Anders Dalsgaard

    2006-01-01

    This study was done to assess the risk of helminth infection in association with wastewater-fed rice cultivation in an agricultural setting of Nam Dinh city, Vietnam. In a cross sectional survey data were collected for 202 households in a commune where wastewater was used for irrigation and for 201 households in a commune that used river water. Parasitological examination was

  20. Magnaporthe grisea infection triggers RNA variation and antisense transcript expression in rice.

    PubMed

    Gowda, Malali; Venu, R-C; Li, Huameng; Jantasuriyarat, Chatchawan; Chen, Songbiao; Bellizzi, Maria; Pampanwar, Vishal; Kim, HyeRan; Dean, Ralph A; Stahlberg, Eric; Wing, Rod; Soderlund, Cari; Wang, Guo-Liang

    2007-05-01

    Rice blast disease, caused by the fungal pathogen Magnaporthe grisea, is an excellent model system to study plant-fungal interactions and host defense responses. In this study, comprehensive analysis of the rice (Oryza sativa) transcriptome after M. grisea infection was conducted using robust-long serial analysis of gene expression. A total of 83,382 distinct 21-bp robust-long serial analysis of gene expression tags were identified from 627,262 individual tags isolated from the resistant (R), susceptible (S), and control (C) libraries. Sequence analysis revealed that the tags in the R and S libraries had a significant reduced matching rate to the rice genomic and expressed sequences in comparison to the C library. The high level of one-nucleotide mismatches of the R and S library tags was due to nucleotide conversions. The A-to-G and U-to-C nucleotide conversions were the most predominant types, which were induced in the M. grisea-infected plants. Reverse transcription-polymerase chain reaction analysis showed that expression of the adenine deaminase and cytidine deaminase genes was highly induced after inoculation. In addition, many antisense transcripts were induced in infected plants and expression of four antisense transcripts was confirmed by strand-specific reverse transcription-polymerase chain reaction. These results demonstrate that there is a series of dynamic and complex transcript modifications and changes in the rice transcriptome at the M. grisea early infection stages. PMID:17351054

  1. Magnaporthe grisea Infection Triggers RNA Variation and Antisense Transcript Expression in Rice1[W

    PubMed Central

    Gowda, Malali; Venu, R.-C.; Li, Huameng; Jantasuriyarat, Chatchawan; Chen, Songbiao; Bellizzi, Maria; Pampanwar, Vishal; Kim, HyeRan; Dean, Ralph A.; Stahlberg, Eric; Wing, Rod; Soderlund, Cari; Wang, Guo-Liang

    2007-01-01

    Rice blast disease, caused by the fungal pathogen Magnaporthe grisea, is an excellent model system to study plant-fungal interactions and host defense responses. In this study, comprehensive analysis of the rice (Oryza sativa) transcriptome after M. grisea infection was conducted using robust-long serial analysis of gene expression. A total of 83,382 distinct 21-bp robust-long serial analysis of gene expression tags were identified from 627,262 individual tags isolated from the resistant (R), susceptible (S), and control (C) libraries. Sequence analysis revealed that the tags in the R and S libraries had a significant reduced matching rate to the rice genomic and expressed sequences in comparison to the C library. The high level of one-nucleotide mismatches of the R and S library tags was due to nucleotide conversions. The A-to-G and U-to-C nucleotide conversions were the most predominant types, which were induced in the M. grisea-infected plants. Reverse transcription-polymerase chain reaction analysis showed that expression of the adenine deaminase and cytidine deaminase genes was highly induced after inoculation. In addition, many antisense transcripts were induced in infected plants and expression of four antisense transcripts was confirmed by strand-specific reverse transcription-polymerase chain reaction. These results demonstrate that there is a series of dynamic and complex transcript modifications and changes in the rice transcriptome at the M. grisea early infection stages. PMID:17351054

  2. First report of Candidatus Liberibacter asiaticus infecting citrus in the Dominican Republic

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Real-time and conventional PCR were used to amplify sequences from the 16S rDNA and the outer membrane protein (omp) gene from nucleic acid extracts from 16 citrus samples from the Dominican Republic which displayed symptoms of the huanglungbing disease caused by the bacterium Candidatus Liberibacte...

  3. Penicillium digitatum suppresses production of hydrogen peroxide in host tissue during infection of citrus fruit

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During the development of green mold disease (Penicillium digitatum) on citrus fruit, there is little evidence of a host resistance response against the invading fungus. This suggests that P. digitatum has the ability to suppress host defenses. Current knowledge of plant-fungal interactions indica...

  4. Isolation and characterization of an Isaria fumosorosea isolate infecting the Asian citrus psyllid in Florida.

    PubMed

    Meyer, Jason M; Hoy, Marjorie A; Boucias, Drion G

    2008-09-01

    A fungal pathogen that killed adult Diaphorina citri Kuwayama (Asian citrus psyllid) (Hemiptera: Psyllidae) in Florida citrus groves during the fall of 2005 was identified and characterized. Investigation of this pathogen is important because D. citri vectors citrus greening disease (Huanglongbing), which was reported in Florida in 2005. The morphological and genetic data generated herein support identification of the fungus as Isaria fumosorosea Wize (Ifr) (=Paecilomyces fumosoroseus) (Hypocreales: Cordycipitaceae) from the Asian citrus psyllid (Ifr AsCP). Koch's postulates were fulfilled after the fungus was isolated in vitro and transmitted to healthy psyllids, which then exhibited a diseased-phenotype similar to that observed in the field. Both in vitro growth characteristics and two Ifr AsCP-specific molecular markers discriminated the psyllid pathogen from another local Ifr isolate, Ifr 97 Apopka. These molecular markers will be useful to track the dynamics of this disease in D. citri populations. The potential for utilizing Ifr to complement existing psyllid pest management strategies is discussed. PMID:18433768

  5. Effect of chemical compounds on the ‘Cadidatus Liberibacter asiaticus’ infected pomelo (Citrus maxima)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB), also known as citrus greening, is one of the most destructive diseases affecting Rutaceae plants in many parts of the world. HLB is associated with three species of ‘Candidatus Liberibacter’ with ‘Ca. L. asiaticus’ (Las), being the most widely distributed in Thailand and Asia. T...

  6. Incidence and severity of huanglongbing and Candidatus Liberibacter asiaticus titer among field-infected citrus cultivars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Incidence and severity of Huanglongbing (HLB) disease were assessed in April, 2010 among eight citrus cultivars representing diverse scion types growing in commercial groves in Florida’s Indian River region, an area with high incidence of HLB. Twenty trees of each cultivar were rated for visual HLB...

  7. Secondary metabolite profiles of leaves of healthy and huanglongbing-infected orange (Citrus sinensis L.) seedlings measured by HPLC-fluorescence detection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leaves of greenhouse-grown ‘Hamlin’ and ‘Valencia’ orange (Citrus sinensis L.) seedlings were analyzed by high performance liquid chromatography in a study of the progression of changes in secondary metabolite profiles resulting from infection by Candidatus Liberibacter asiaticus (CLas), the Huanglo...

  8. Bacterial diversity analysis of Huanglongbing pathogen-infected citrus, using PhyloChip and 16S rRNA gene clone library sequencing

    SciTech Connect

    Shankar Sagaram, U.; DeAngelis, K.M.; Trivedi, P.; Andersen, G.L.; Lu, S.-E.; Wang, N.

    2009-03-01

    The bacterial diversity associated with citrus leaf midribs was characterized 1 from citrus groves that contained the Huanglongbing (HLB) pathogen, which has yet to be cultivated in vitro. We employed a combination of high-density phylogenetic 16S rDNA microarray and 16S rDNA clone library sequencing to determine the microbial community composition of symptomatic and asymptomatic citrus midribs. Our results revealed that citrus leaf midribs can support a diversity of microbes. PhyloChip analysis indicated that 47 orders of bacteria from 15 phyla were present in the citrus leaf midribs while 20 orders from phyla were observed with the cloning and sequencing method. PhyloChip arrays indicated that nine taxa were significantly more abundant in symptomatic midribs compared to asymptomatic midribs. Candidatus Liberibacter asiaticus (Las) was detected at a very low level in asymptomatic plants, but was over 200 times more abundant in symptomatic plants. The PhyloChip analysis was further verified by sequencing 16S rDNA clone libraries, which indicated the dominance of Las in symptomatic leaves. These data implicate Las as the pathogen responsible for HLB disease. Citrus is the most important commercial fruit crop in Florida. In recent years, citrus Huanglongbing (HLB), also called citrus greening, has severely affected Florida's citrus production and hence has drawn an enormous amount of attention. HLB is one of the most devastating diseases of citrus (6,13), characterized by blotchy mottling with green islands on leaves, as well as stunting, fruit decline, and small, lopsided fruits with poor coloration. The disease tends to be associated with a phloem-limited fastidious {alpha}-proteobacterium given a provisional Candidatus status (Candidatus Liberobacter spp. later changed to Candidatus Liberibacter spp.) in nomenclature (18,25,34). Previous studies indicate that HLB infection causes disorder in the phloem and severely impairs the translocation of assimilates in host plants (5,27,40). Tatineni and colleagues discovered that the HLB bacteria were unevenly distributed in phloem of bark tissue, vascular tissue of the leaf midrib, roots, and different floral and fruit parts (43). Unsuccessful attempts in culturing the pathogen are notably hampering efforts to understand its biology and pathogenesis mechanism. Using a modified Koch's Postulates approach, Jagoueix and colleagues were able to re-infect periwinkle plants from a mixed microbial community harvested from HLB diseased plants (25). Emergence of the disease in otherwise healthy plants led to the conclusion that HLB was associated with Candidatus Liberibacter sp. based on its 16S rDNA sequence (18,25). Currently, three species of the pathogen are recognized from trees with HLB disease based on 16S rDNA sequence: Ca. Liberibacter asiaticus (Las), Ca. Liberibacter africanus (Laf), and Ca. Liberibacter americanus (Lam); Las is the most prevalent species among HLB diseased trees (5,12,18,25,44). Las is naturally transmitted to citrus by the psyllid, Diaphorina citri Kuwayama, and can be artificially transmitted by grafting from citrus to citrus and dodder (Cuscuta campestris) to periwinkle (Catharanthus roseus) or tobacco (Nicotiana tabacum Xanthi) (5). Based on current research regarding the associations of Liberibacter in planta there is not enough evidence to implicate Liberibacter as the definitive causal agent of HLB disease due to its resistance to cultivation in vitro. It is possible that HLB disease may be the result of complex etiology where Liberibacter interacts with other endophytic bacteria. However, there is not enough evidence regarding its association(s) in planta to make this conclusion, nor is it known whether associated microbial communities play a role in expression of pathogenic traits. The main objective of the study was to test the hypothesis that other bacteria besides Ca. Liberibacter spp. are associated with citrus greening disease. The differences between the relative abundance, species richness and phylogenetic diversity of the microbial communitie

  9. Genetic variation in strigolactone production and tillering in rice and its effect on Striga hermonthica infection.

    PubMed

    Jamil, Muhammad; Charnikhova, Tatsiana; Houshyani, Benyamin; van Ast, Aad; Bouwmeester, Harro J

    2012-03-01

    Tillering in cereals is a complex process in the regulation of which also signals from the roots in the form of strigolactones play an important role. The strigolactones are signalling molecules that are secreted into the rhizosphere where they act as germination stimulants for root parasitic plants and hyphal branching factors for arbuscular mycorrhizal fungi. On the other hand, they are also transported from the roots to the shoot where they inhibit tillering or branching. In the present study, the genetic variation in strigolactone production and tillering phenotype was studied in twenty rice varieties collected from all over the world and correlated with S. hermonthica infection. Rice cultivars like IAC 165, IAC 1246, Gangweondo and Kinko produced high amounts of the strigolactones orobanchol, 2'-epi-5-deoxystrigol and three methoxy-5-deoxystrigol isomers and displayed low amounts of tillers. These varieties induced high S. hermonthica germination, attachment, emergence as well as dry biomass. In contrast, rice cultivars such as Super Basmati, TN 1, Anakila and Agee displayed high tillering in combination with low production of the aforementioned strigolactones. These varieties induced only low S. hermonthica germination, attachment, emergence and dry biomass. Statistical analysis across all the varieties confirmed a positive correlation between strigolactone production and S. hermonthica infection and a negative relationship with tillering. These results show that genetic variation in tillering capacity is the result of genetic variation in strigolactone production and hence could be a helpful tool in selecting rice cultivars that are less susceptible to S. hermonthica infection. PMID:21947621

  10. Rice blast infection of Brachypodium distachyon as a model system to study dynamic host\\/pathogen interactions

    Microsoft Academic Search

    David Parker; Manfred Beckmann; David P Enot; David P Overy; Zaira Caracuel Rios; Martin Gilbert; Nicholas Talbot; John Draper

    2008-01-01

    Interactions between plants and compatible fungal pathogens are spatially and temporally dynamic, posing a major challenge for sampling and data analysis. A protocol is described for the infection of the model grass species Brachypodium distachyon with Magnaporthe grisea (rice blast), together with modifications to extend the use to rice and barley. We outline a method for the preparation of long-term

  11. Herbivory by the insect diaphorina citri induces greater change in citrus plant volatile profile than does infection by the bacterium, Candidatus Liberibacter asiaticus

    PubMed Central

    Hijaz, Faraj; El-Shesheny, Ibrahim; Killiny, Nabil

    2013-01-01

    The volatile organic compound (VOC) profile in plant leaves often changes after biotic and abiotic stresses. Monitoring changes in VOCs in plant leaves could provide valuable information about multitrophic interactions. In the current study, we investigated the effect of Asian citrus psyllid (ACP) infestation, citrus greening pathogen (Candidatus Liberibacter asiaticus [CLas]) infection, and simultaneous attack by ACP and CLas on the VOC content of citrus leaves. Leaf volatiles were extracted using hexane and analyzed with gas chromatography-mass spectrometry (GC-MS). Although ACP is a phloem-sucking insect that causes minimal damage to plant tissues, the relative amount of 21 out of the 27 VOCs increased 2- to 10-fold in ACP-infested plants. The relative amount of d-limonene, ?-phelandrene, citronellal, and undecanal were increased 4- to 20- fold in CLas-infected plants. A principle component analysis (PCA) and cluster analysis (CA) showed that VOC patterns of ACP-infested and CLas-infected plants were different from each other and were also different from the controls, while the VOC pattern of double-attacked plants was more like that of the controls than that of ACP-infested or CLas-infected plants. VOC amounts from leaves were compromised when plants were attacked by ACP and CLas. The results of this study showed that a simple direct extraction of citrus leaf volatiles could be successfully used to discriminate between healthy and CLas-infected plants. Information about the effects of insect and pathogen attack on the VOC content profile of plants might contribute to a better understanding of biotic stress. PMID:23857364

  12. Herbivory by the insect diaphorina citri induces greater change in citrus plant volatile profile than does infection by the bacterium, Candidatus Liberibacter asiaticus.

    PubMed

    Hijaz, Faraj; El-Shesheny, Ibrahim; Killiny, Nabil

    2013-10-01

    The volatile organic compound (VOC) profile in plant leaves often changes after biotic and abiotic stresses. Monitoring changes in VOCs in plant leaves could provide valuable information about multitrophic interactions. In the current study, we investigated the effect of Asian citrus psyllid (ACP) infestation, citrus greening pathogen (Candidatus Liberibacter asiaticus [CLas]) infection, and simultaneous attack by ACP and CLas on the VOC content of citrus leaves. Leaf volatiles were extracted using hexane and analyzed with gas chromatography-mass spectrometry (GC-MS). Although ACP is a phloem-sucking insect that causes minimal damage to plant tissues, the relative amount of 21 out of the 27 VOCs increased 2- to 10-fold in ACP-infested plants. The relative amount of d-limonene, ?-phelandrene, citronellal, and undecanal were increased 4- to 20- fold in CLas-infected plants. A principle component analysis (PCA) and cluster analysis (CA) showed that VOC patterns of ACP-infested and CLas-infected plants were different from each other and were also different from the controls, while the VOC pattern of double-attacked plants was more like that of the controls than that of ACP-infested or CLas-infected plants. VOC amounts from leaves were compromised when plants were attacked by ACP and CLas. The results of this study showed that a simple direct extraction of citrus leaf volatiles could be successfully used to discriminate between healthy and CLas-infected plants. Information about the effects of insect and pathogen attack on the VOC content profile of plants might contribute to a better understanding of biotic stress. PMID:23857364

  13. An NADPH-dependent genetic switch regulates plant infection by the rice blast fungus.

    PubMed

    Wilson, Richard A; Gibson, Robert P; Quispe, Cristian F; Littlechild, Jennifer A; Talbot, Nicholas J

    2010-12-14

    To cause rice blast disease, the fungus Magnaporthe oryzae breaches the tough outer cuticle of the rice leaf by using specialized infection structures called appressoria. These cells allow the fungus to invade the host plant and proliferate rapidly within leaf tissue. Here, we show that a unique NADPH-dependent genetic switch regulates plant infection in response to the changing nutritional and redox conditions encountered by the pathogen. The biosynthetic enzyme trehalose-6-phosphate synthase (Tps1) integrates control of glucose-6-phosphate metabolism and nitrogen source utilization by regulating the oxidative pentose phosphate pathway, the generation of NADPH, and the activity of nitrate reductase. We report that Tps1 directly binds to NADPH and, thereby, regulates a set of related transcriptional corepressors, comprising three proteins, Nmr1, Nmr2, and Nmr3, which can each bind NADP. Targeted deletion of any of the Nmr-encoding genes partially suppresses the nonpathogenic phenotype of a ?tps1 mutant. Tps1-dependent Nmr corepressors control the expression of a set of virulence-associated genes that are derepressed during appressorium-mediated plant infection. When considered together, these results suggest that initiation of rice blast disease by M. oryzae requires a regulatory mechanism involving an NADPH sensor protein, Tps1, a set of NADP-dependent transcriptional corepressors, and the nonconsuming interconversion of NADPH and NADP acting as signal transducer. PMID:21115813

  14. Expressed Genes in Asian Citrus Psyllid adults feeding on citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We created and described the first genetic data set from the Asian citrus psyllid, AsCP, Diaphorina citri, Kuwayama (Hemiptera: Psyllidae). The AsCP spread the plant-infecting bacterium, Candidatus Liberibacter asiaticus, which is associated with the citrus disease Huanglongbing, HLB, known as Citru...

  15. Wolbachia in the Asian rice gall midge, Orseolia oryzae (Wood-Mason): correlation between host mitotypes and infection status.

    PubMed

    Behura, S K; Sahu, S C; Mohan, M; Nair, S

    2001-04-01

    Using a PCR-based method, we detected Wolbachia in the Asian rice gall midge. Furthermore, results showed that all females across all biotypes are infected with Wolbachia. However, all male flies are not infected and show different infection frequency in different biotypes. We have also identified three mitotypes, in the rice gall midge, based on DraI restriction pattern of a portion of the 12S rRNA gene that was PCR amplified using primers specific to this gene. All the females and infected male flies had type 1 mtDNA while uninfected males showed only type 2 or 3 mtDNA. Inheritance patterns of mtDNA revealed the existence of a correlation between mtDNA type and Wolbachia infection in the Asian rice gall midge. Evidence for paternal inheritance of mtDNA in Wolbachia-free gall midge is also presented. PMID:11422512

  16. Transcriptome Profiling of Citrus Fruit Response to Huanglongbing Disease

    E-print Network

    D'Souza, Raissa

    Transcriptome Profiling of Citrus Fruit Response to Huanglongbing Disease Federico Martinelli1) or ``citrus greening'' is the most destructive citrus disease worldwide. In this work, we studied host responses of citrus to infection with Candidatus Liberibacter asiaticus (CaLas) using next

  17. Effect of the nematode biocide Dbx-1003 in controlling citrus nematode infecting Mandarin, and interrelationship with the co-inhabitant fungi.

    PubMed

    Noweer, E M A

    2013-01-01

    In a field experiment, the nematode-biocide, Dbx-1003, was evaluated against the citrus nematode, Tylenchulus semipenetrans infecting Mandarin, Citrus reticulata, Dbx-1003 20% G., was applied in October 2008 at the rate 1/2 kg/tree, and root and soil samples were collected monthly until the next October, 2009. Successive treatment of the same biocide was added in May 2009. For the comparison, Vydate 24% L, was applied as well as non-treated check trees were left. Data revealed that the biocide treatment greatly affected the citrus nematode numbers both in soil and roots, in comparing with those of Vydate or induced by Dbx-1003 was 97% and 70%; respectively in soil and roots. Rates of reproduction increase of the citrus nematode also reached 3% and 30% in both soil and roots; respectively. Vydate treatment resulted in a relatively lesser percentages. Growth of the concomitant fungus, Trichoderma sp. was increased specially in the last samples of October 2009, however those of fungi; Aspergillus flavus, Fusarium sp. and Rhizopus sp. were reduced, due to Dbx-1003 treatment. Aspergillus niger and Penicillium sp. were not affected by the presence of the biocide. Vydate did not affect the co-inhabitant fungi to a great extent. PMID:25151818

  18. Oral immunization of fish against iridovirus infection using recombinant antigen produced from rice callus.

    PubMed

    Shin, Y J; Kwon, T H; Seo, J Y; Kim, T J

    2013-10-25

    Fish iridoviruses cause systemic diseases with high morbidity and mortality in various species of wild and farm-raised fish, resulting in severe economic losses, and no large-scale protective vaccine program or therapy is currently available. In this study, we expressed a recombinant major capsid protein (rMCP) of rock bream iridovirus in transgenic rice callus. The rMCP in lyophilized rice callus powder was added to feed to induce intestinal mucosal immunity for protection against and/or to reduce the severity of the iridovirus infection. We found that fish (Rock bream) immunized orally with rMCP underwent successful induction of antibodies (P<0.05) and were protected (P<0.001) against viral challenge. These results suggest that oral administration of rMCP as an antigen is a useful method to implement a vaccine program against iridovirus and other marine viral diseases. PMID:24021312

  19. Gene expression in Citrus sinensis (L.) Osbeck following infection with the bacterial pathogen Candidatus Liberibacter asiaticus causing Huanglongbing in Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hunglongbing (HLB) (=citrus greening) is a destructive disease of citrus which is caused by a fastidious, phloem-inhabiting bacterium of the genus Candidatus Liberibacter. Large-scale analysis of gene expression changes in ‘Valencia’ orange leaves were studied during the course of 19 weeks after in...

  20. Callose deposition and inhibited symplastic transport in the phloem of citrus leaves infected with Candidatus Liberibacter asiaticus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is a lethal disease of citrus, damaging citrus agriculture worldwide. A phloem-limited, alpha proteobacterium, Candidatus Liberibacter asiaticus (Las) is associated with HLB in North America. We examined Lasinfected (Las+) leaf phloem cells by microscopy methods to characterize p...

  1. Comparison of FTIR spectra between Huanglongbing (citrus greening) and other citrus maladies.

    PubMed

    Hawkins, Samantha A; Park, Bosoon; Poole, Gavin H; Gottwald, Tim R; Windham, William R; Albano, Joseph; Lawrence, Kurt C

    2010-05-26

    Fourier transform infrared (FTIR) spectroscopy has the ability to quickly identify the presence of specific carbohydrates in plant materials. The presence of the disease huanglongbing (HLB) in the leaves of infected citrus plants has a distinctive spectrum that can be used to distinguish an infected plant from a healthy plant. However, many citrus diseases display similar visible symptoms and are of concern to citrus growers. In this study several citrus diseases (citrus leaf rugose virus, citrus tristeza virus, citrus psorosis virus, and Xanthomonas axonopodis ) and nutrient deficiencies (iron, copper, zinc, manganese, and magnesium) were compared with HLB using FTIR spectroscopy to determine if the spectra alone can be used to identify plants that are infected with HLB instead of another disease. The results indicate that the spectra of some diseases and deficiencies more closely resemble those of apparently healthy plants and some share the carbohydrate transformation that has been seen in the spectra of HLB-infected plants. PMID:20438136

  2. Heat shock protein 70 is necessary for Rice stripe virus infection in plants.

    PubMed

    Jiang, Shanshan; Lu, Yuwen; Li, Kunfeng; Lin, Lin; Zheng, Hongying; Yan, Fei; Chen, Jianping

    2014-12-01

    Heat shock proteins 70 (HSP70s) are a highly conserved family of genes in eukaryotes, and are involved in a remarkable variety of cellular processes. In many plant positive-stranded RNA viruses, HSP70 participates in the construction of a viral replication complex and plays various roles during viral infection. Here, we found increased expression of HSP70 following infection by Rice stripe virus (RSV), a negative-stranded RNA virus, in both rice (the natural host) and Nicotiana benthamiana (an experimental host). Heat treatment of N.?benthamiana (Nb) plants enhanced viral infection, whereas RSV infection was retarded and viral RNAs accumulated at a low level when HSP70 was silenced. In both bimolecular fluorescence complement and in?vitro pull-down assays, the N-terminus of RSV RNA-dependent RNA polymerase (RdRp) interacted and co-localized with the HSP70s of both plants (OsHSP70 and NbHSP70). The localization of the N-terminus of RdRp when expressed alone was not obviously different from when it was co-expressed with OsHSP or NbHSP, and vice versa. RSV infection also had no effect on the localization of host HSP70. These results demonstrate that host HSP70 is necessary for RSV infection and probably plays a role in viral replication by interacting with viral RdRp, which provides the first evidence of an interacting host protein related to RSV replication, which has been little studied to date. PMID:24823923

  3. Leaf Gas Exchange and Chlorophyll a Fluorescence Imaging of Rice Leaves Infected with Monographella albescens.

    PubMed

    Tatagiba, Sandro Dan; DaMatta, Fábio Murilo; Rodrigues, Fabrício Ávila

    2015-02-01

    This study was intended to analyze the photosynthetic performance of rice leaf blades infected with Monographella albescens by combining chlorophyll (Chl) a fluorescence images with gas exchange and photosynthetic pigment pools. The net CO2 assimilation rate, stomatal conductance, transpiration rate, total Chl and carotenoid pools, and Chl a/b ratio all decreased but the internal CO2 concentration increased in the inoculated plants compared with their noninoculated counterparts. The first detectable changes in the images of Chl a fluorescence from the leaves of inoculated plants were already evident at 24 h after inoculation (hai) and increased dramatically as the leaf scald lesions expanded. However, these changes were negligible for the photosystem II photochemical efficiency (Fv/Fm) at 24 hai, in contrast to other Chl fluorescence traits such as the photochemical quenching coefficient, yield of photochemistry, and yield for dissipation by downregulation; which, therefore, were much more sensitive than the Fv/Fm ratio in assessing the early stages of fungal infection. It was also demonstrated that M. albescens was able to impair the photosynthetic process in both symptomatic and asymptomatic leaf areas. Overall, it was proven that Chl a fluorescence imaging is an excellent tool to describe the loss of functionality of the photosynthetic apparatus occurring in rice leaves upon infection by M. albescens. PMID:25163009

  4. RNA-Seq analysis of Citrus reticulata in the early stages of Xylella fastidiosa infection reveals auxin-related genes as a defense response

    PubMed Central

    2013-01-01

    Background Citrus variegated chlorosis (CVC), caused by Xylella fastidiosa, is one the most important citrus diseases, and affects all varieties of sweet orange (Citrus sinensis L. Osb). On the other hand, among the Citrus genus there are different sources of resistance against X. fastidiosa. For these species identifying these defense genes could be an important step towards obtaining sweet orange resistant varieties through breeding or genetic engineering. To assess these genes we made use of mandarin (C. reticulata Blanco) that is known to be resistant to CVC and shares agronomical characteristics with sweet orange. Thus, we investigated the gene expression in Ponkan mandarin at one day after infection with X. fastidiosa, using RNA-seq. A set of genes considered key elements in the resistance was used to confirm its regulation in mandarin compared with the susceptible sweet orange. Results Gene expression analysis of mock inoculated and infected tissues of Ponkan mandarin identified 667 transcripts repressed and 724 significantly induced in the later. Among the induced transcripts, we identified genes encoding proteins similar to Pattern Recognition Receptors. Furthermore, many genes involved in secondary metabolism, biosynthesis and cell wall modification were upregulated as well as in synthesis of abscisic acid, jasmonic acid and auxin. Conclusions This work demonstrated that the defense response to the perception of bacteria involves cell wall modification and activation of hormone pathways, which probably lead to the induction of other defense-related genes. We also hypothesized the induction of auxin-related genes indicates that resistant plants initially recognize X. fastidiosa as a necrotrophic pathogen. PMID:24090429

  5. 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

  6. The role of catalase-peroxidase secreted by Magnaporthe oryzae during early infection of rice cells.

    PubMed

    Tanabe, Shigeru; Ishii-Minami, Naoko; Saitoh, Ken-Ichiro; Otake, Yuko; Kaku, Hanae; Shibuya, Naoto; Nishizawa, Yoko; Minami, Eiichi

    2011-02-01

    The biological role of a secretory catalase of the rice blast fungus Magnaporthe oryzae was studied. The internal amino acid sequences of the partially purified catalase in the culture filtrate enabled us to identify its encoding gene as a catalase-peroxidase gene, CPXB, among four putative genes for catalase or catalase-peroxidase in M. oryzae. Knockout of the gene drastically reduced the level of catalase activity in the culture filtrate and supernatant of conidial suspension (SCS), and increased the sensitivity to exogenously added H?O? compared with control strains, suggesting that CPXB is the major gene encoding the secretory catalase and confers resistance to H?O? in hyphae. In the mutant, the rate of appressoria that induced accumulation of H?O? in epidermal cells of the leaf sheath increased and infection at early stages was delayed; however, the formation of lesions in the leaf blade was not affected compared with the control strain. These phenotypes were complimented by reintroducing the putative coding regions of CPXB driven by a constitutive promoter. These results suggest that CPXB plays a role in fungal defense against H?O? accumulated in epidermal cells of rice at the early stage of infection but not in pathogenicity of M. oryzae. PMID:21043575

  7. Visible/near-infrared spectroscopy for discrimination of HLB-infected citrus leaves from healthy leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Researchers have used various hyperspectral systems, covering several areas of the electromagnetic spectrum to investigate all types of disease/plant interactions. The purpose of this research was to investigate using visible and near-infrared (400-1100nm) spectroscopy to differentiate HLB infected...

  8. Screening molecules for control of citrus huanglongbing using an optimized regeneration system for 'Candidatus Liberibacter asiaticus'-infected periwinkle (Catharanthus roseus) cuttings.

    PubMed

    Zhang, Muqing; Duan, Yongping; Zhou, Lijuan; Turechek, William W; Stover, Ed; Powell, Charles A

    2010-03-01

    Citrus huanglongbing is one of the most destructive diseases of citrus worldwide. The disease is associated with three different species of 'Candidatus Liberibacter', of which 'Ca. L. asiaticus' is the most widely distributed. An optimized system using 'Ca. L. asiaticus'-infected periwinkle cuttings was developed to screen chemical compounds effective for controlling the bacterial population while simultaneously assessing their phytotoxicity. The optimal regeneration conditions were determined to be the use of vermiculite as a growth medium for the cuttings, and a fertilization routine using half-strength Murashige and Tucker medium supplemented with both naphthalene acetic acid (4 microg/ml) and indole-3-butyric acid (4 microg/ml). This system allowed a plant regeneration rate of 60.6% for 'Ca. L. asiaticus'-infected cuttings in contrast to the <1% regeneration rate with water alone. Two chemical agents, penicillin G sodium and 2,2-dibromo-3-nitrilopropionamide (DBNPA), were found to be effective at eliminating or suppressing the 'Ca. L. asiaticus' bacterium in this periwinkle regeneration system. When treated with penicillin G sodium at 50 microg/ml, all plants regenerated from 'Ca. L. asiaticus'-infected cuttings were 'Ca. L. asiaticus' negative as determined by both nested polymerase chain reaction (PCR) and quantitative real-time PCR. In addition, DBNPA was also able to significantly reduce the percentage of 'Ca. L. asiaticus'-positive plants and the titer of the 'Ca. L. asiaticus' bacterium at 200 microl/liter. PMID:20128697

  9. Transcriptome profiling confirmed correlations between symptoms and transcriptional changes in RDV infected rice and revealed nucleolus as a possible target of RDV manipulation

    PubMed Central

    2014-01-01

    Background Rice dwarf virus (RDV) is the causal agent of rice dwarf disease, which limits rice production in many areas of south East Asia. Transcriptional changes of rice in response to RDV infection have been characterized by Shimizu et al. and Satoh et al.. Both studies found induction of defense related genes and correlations between transcriptional changes and symptom development in RDV-infected rice. However, the same rice cultivar, namely Nipponbare belonging to the Japonic subspecies of rice was used in both studies. Methods Gene expression changes of the indica subspecies of rice, namely Oryza sativa L. ssp. indica cv Yixiang2292 that show moderate resistance to RDV, in response to RDV infection were characterized using an Affymetrix Rice Genome Array. Differentially expressed genes (DEGs) were classified according to their Gene Ontology (GO) annotation. The effects of transient expression of Pns11 in Nicotiana benthaminana on the expression of nucleolar genes were studied using real-time PCR (RT-PCR). Results 856 genes involved in defense or other physiological processes were identified to be DEGs, most of which showed up-regulation. Ribosome- and nucleolus related genes were significantly enriched in the DEGs. Representative genes related to nucleolar function exhibited altered expression in N. benthaminana plants transiently expressing Pns11 of RDV. Conclusions Induction of defense related genes is common for rice infected with RDV. There is a co-relation between symptom severity and transcriptional alteration in RDV infected rice. Besides ribosome, RDV may also target nucleolus to manipulate the translation machinery of rice. Given the tight links between nucleolus and ribosome, it is intriguing to speculate that RDV may enhance expression of ribosomal genes by targeting nucleolus through Pns11. PMID:24885215

  10. Infection-Associated Nuclear Degeneration in the Rice Blast Fungus Magnaporthe oryzae Requires Non-Selective Macro-Autophagy

    PubMed Central

    He, Min; Kershaw, Michael J.; Soanes, Darren M.; Xia, Yuxian; Talbot, Nicholas J.

    2012-01-01

    Background The rice blast fungus Magnaporthe oryzae elaborates a specialized infection structure called an appressorium to breach the rice leaf surface and gain access to plant tissue. Appressorium development is controlled by cell cycle progression, and a single round of nuclear division occurs prior to appressorium formation. Mitosis is always followed by programmed cell death of the spore from which the appressorium develops. Nuclear degeneration in the spore is known to be essential for plant infection, but the precise mechanism by which it occurs is not known. Methodology/Principal Findings In yeast, nuclear breakdown requires a specific form of autophagy, known as piecemeal microautophagy of the nucleus (PMN), and we therefore investigated whether this process occurs in the rice blast fungus. Here, we report that M. oryzae possesses two conserved components of a putative PMN pathway, MoVac8 and MoTsc13, but that both are dispensable for nuclear breakdown during plant infection. MoVAC8 encodes a vacuolar membrane protein and MoTSC13 a peri-nuclear and peripheral ER protein. Conclusions/Significance We show that MoVAC8 is necessary for caffeine resistance, but dispensable for pathogenicity of M. oryzae, while MoTSC13 is involved in cell wall stress responses and is an important virulence determinant. By functional analysis of ?Moatg1 and ?Moatg4 mutants, we demonstrate that infection-associated nuclear degeneration in M. oryzae instead occurs by non-selective macroautophagy, which is necessary for rice blast disease. PMID:22448240

  11. The epidemiological significance of post-packinghouse survival of Xanthomonas citri ssp. citri for dissemination of Asiatic citrus canker via infected fruit

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The risk of introduction of Xanthomonas citri spp. citri (Xcc) to new, unaffected citrus producing areas is a major concern for those citrus industries attempting to remain free of citrus canker. Citrus fruit, as a potential pathway for Xcc to enter and become established in these areas, is assumed...

  12. Confirmation of the sequence of 'Candidatus Liberibacter asiaticus' and assessment of microbial diversity in Huanglongbing-infected citrus phloem using a metagenomic approach.

    PubMed

    Tyler, Heather L; Roesch, Luiz F W; Gowda, Siddarame; Dawson, William O; Triplett, Eric W

    2009-12-01

    The citrus disease Huanglongbing (HLB) is highly destructive in many citrus-growing regions of the world. The putative causal agent of this disease, 'Candidatus Liberibacter asiaticus', is difficult to culture, and Koch's postulates have not yet been fulfilled. As a result, efforts have focused on obtaining the genome sequence of 'Ca. L. asiaticus' in order to give insight on the physiology of this organism. In this work, three next-generation high-throughput sequencing platforms, 454, Solexa, and SOLiD, were used to obtain metagenomic DNA sequences from phloem tissue of Florida citrus trees infected with HLB. A culture-independent, polymerase chain reaction (PCR)-independent analysis of 16S ribosomal RNA sequences showed that the only bacterium present within the phloem metagenome was 'Ca L. asiaticus'. No viral or viroid sequences were identified within the metagenome. By reference assembly, the phloem metagenome contained sequences that provided 26-fold coverage of the 'Ca. L. asiaticus' contigs in GenBank. By the same approach, phloem metagenomic data yielded less than 0.2-fold coverage of five other alphaproteobacterial genomes. Thus, phloem metagenomic DNA provided a PCR-independent means of verifying the presence of 'Ca L. asiaticus' in infected tissue and strongly suggests that no other disease agent was present in phloem. Analysis of these metagenomic data suggest that this approach has a detection limit of one 'Ca. Liberibacter' cell for every 52 phloem cells. The phloem sample sequenced here is estimated to have contained 1.7 'Ca. Liberibacter' cells per phloem cell. PMID:19888827

  13. RL-SAGE and microarray analysis of the rice transcriptome after Rhizoctonia solani infection.

    PubMed

    Venu, R C; Jia, Yulin; Gowda, Malali; Jia, Melissa H; Jantasuriyarat, Chatchawan; Stahlberg, Eric; Li, Huameng; Rhineheart, Andrew; Boddhireddy, Prashanth; Singh, Pratibha; Rutger, Neil; Kudrna, David; Wing, Rod; Nelson, James C; Wang, Guo-Liang

    2007-10-01

    Sheath blight caused by the fungal pathogen Rhizoctonia solani is an emerging problem in rice production worldwide. To elucidate the molecular basis of rice defense to the pathogen, RNA isolated from R. solani-infected leaves of Jasmine 85 was used for both RL-SAGE library construction and microarray hybridization. RL-SAGE sequence analysis identified 20,233 and 24,049 distinct tags from the control and inoculated libraries, respectively. Nearly half of the significant tags (> or =2 copies) from both libraries matched TIGR annotated genes and KOME full-length cDNAs. Among them, 42% represented sense and 7% antisense transcripts, respectively. Interestingly, 60% of the library-specific (> or =10 copies) and differentially expressed (>4.0-fold change) tags were novel transcripts matching genomic sequence but not annotated genes. About 70% of the genes identified in the SAGE libraries showed similar expression patterns (up or down-regulated) in the microarray data obtained from three biological replications. Some candidate RL-SAGE tags and microarray genes were located in known sheath blight QTL regions. The expression of ten differentially expressed RL-SAGE tags was confirmed with RT-PCR. The defense genes associated with resistance to R. solani identified in this study are useful genomic materials for further elucidation of the molecular basis of the defense response to R. solani and fine mapping of target sheath blight QTLs. PMID:17579886

  14. Characterization of Rice Black-Streaked Dwarf Virus- and Rice Stripe Virus-Derived siRNAs in Singly and Doubly Infected Insect Vector Laodelphax striatellus

    PubMed Central

    Shen, Jiangfeng; Lv, Yuanda; Ji, Yongqiang; Sun, Liying; Chen, Jianping

    2013-01-01

    Replication of RNA viruses in insect cells triggers an antiviral defense that is mediated by RNA interference (RNAi) which generates viral-derived small interfering RNAs (siRNAs). However, it is not known whether an antiviral RNAi response is also induced in insects by reoviruses, whose double-stranded RNA genome replication is thought to occur within core particles. Deep sequencing of small RNAs showed that when the small brown planthopper (Laodelphax striatellus) was infected by Rice black-streaked dwarf virus (RBSDV) (Reoviridae; Fijivirus), more viral-derived siRNAs accumulated than when the vector insect was infected by Rice stripe virus (RSV), a negative single-stranded RNA virus. RBSDV siRNAs were predominantly 21 and 22 nucleotides long and there were almost equal numbers of positive and negative sense. RBSDV siRNAs were frequently generated from hotspots in the 5?- and 3?-terminal regions of viral genome segments but these hotspots were not associated with any predicted RNA secondary structures. Under laboratory condition, L. striatellus can be infected simultaneously with RBSDV and RSV. Double infection enhanced the accumulation of particular genome segments but not viral coat protein of RBSDV and correlated with an increase in the abundance of siRNAs derived from RBSDV. The results of this study suggest that reovirus replication in its insect vector potentially induces an RNAi-mediated antiviral response. PMID:23776591

  15. Characterization of rice black-streaked dwarf virus- and rice stripe virus-derived siRNAs in singly and doubly infected insect vector Laodelphax striatellus.

    PubMed

    Li, Junmin; Andika, Ida Bagus; Shen, Jiangfeng; Lv, Yuanda; Ji, Yongqiang; Sun, Liying; Chen, Jianping

    2013-01-01

    Replication of RNA viruses in insect cells triggers an antiviral defense that is mediated by RNA interference (RNAi) which generates viral-derived small interfering RNAs (siRNAs). However, it is not known whether an antiviral RNAi response is also induced in insects by reoviruses, whose double-stranded RNA genome replication is thought to occur within core particles. Deep sequencing of small RNAs showed that when the small brown planthopper (Laodelphax striatellus) was infected by Rice black-streaked dwarf virus (RBSDV) (Reoviridae; Fijivirus), more viral-derived siRNAs accumulated than when the vector insect was infected by Rice stripe virus (RSV), a negative single-stranded RNA virus. RBSDV siRNAs were predominantly 21 and 22 nucleotides long and there were almost equal numbers of positive and negative sense. RBSDV siRNAs were frequently generated from hotspots in the 5'- and 3'-terminal regions of viral genome segments but these hotspots were not associated with any predicted RNA secondary structures. Under laboratory condition, L. striatellus can be infected simultaneously with RBSDV and RSV. Double infection enhanced the accumulation of particular genome segments but not viral coat protein of RBSDV and correlated with an increase in the abundance of siRNAs derived from RBSDV. The results of this study suggest that reovirus replication in its insect vector potentially induces an RNAi-mediated antiviral response. PMID:23776591

  16. The effect of ‘Candidatus Liberibacter asiaticus’ infection on the proteomic profiles and nutritional status of pre-symptomatic and symptomatic grapefruit (Citrus paradisi) plants

    PubMed Central

    2013-01-01

    Background Huanglongbing (HLB) is a highly destructive citrus disease which threatens citrus production worldwide and ‘Candidatus Liberibacter asiaticus’ (Las), a non-culturable phloem-limited bacterium, is an associated causal agent of the disease. To better understand the physiological and molecular processes involved in host responses to Las, 2-DE and mass spectrometry analyses, as well as ICP spectroscopy analysis were employed to elucidate the global protein expression profiles and nutrient concentrations in leaves of Las-infected grapefruit plants at pre-symptomatic or symptomatic stages for HLB. Results This study identified 123 protein spots out of 191 spots that showed significant changes in the leaves of grapefruit plants in response to Las infection and all identified spots matched to 69 unique proteins/peptides. A down-regulation of 56 proteins including those associated with photosynthesis, protein synthesis, and metabolism was correlated with significant reductions in the concentrations of Ca, Mg, Fe, Zn, Mn, and Cu in leaves of grapefruit plants in response to Las infection, particularly in symptomatic plants. Oxygen-evolving enhancer (OEE) proteins, a PSI 9 kDa protein, and a Btf3-like protein were among a small group of proteins that were down-regulated in both pre-symptomatic and symptomatic plants in response to Las infection. Furthermore, a Las-mediated up-regulation of 13 grapefruit proteins was detected, which included Cu/Zn superoxide dismutase, chitinases, lectin-related proteins, miraculin-like proteins, peroxiredoxins and a CAP 160 protein. Interestingly, a Las-mediated up-regulation of granule-bound starch synthase was correlated with an increase in the K concentrations of pre-symptomatic and symptomatic plants. Conclusions This study constitutes the first attempt to characterize the interrelationships between protein expression and nutritional status of Las-infected pre-symptomatic or symptomatic grapefruit plants and sheds light on the physiological and molecular mechanisms associated with HLB disease development. PMID:23578104

  17. Methionine Biosynthesis is Essential for Infection in the Rice Blast Fungus Magnaporthe oryzae

    PubMed Central

    Gagey, Marie Josèphe; Frelin, Océane; Beffa, Roland; Lebrun, Marc Henri; Droux, Michel

    2015-01-01

    Methionine is a sulfur amino acid standing at the crossroads of several biosynthetic pathways. In fungi, the last step of methionine biosynthesis is catalyzed by a cobalamine-independent methionine synthase (Met6, EC 2.1.1.14). In the present work, we studied the role of Met6 in the infection process of the rice blast fungus, Magnaporthe oryzae. To this end MET6 null mutants were obtained by targeted gene replacement. On minimum medium, MET6 null mutants were auxotrophic for methionine. Even when grown in presence of excess methionine, these mutants displayed developmental defects, such as reduced mycelium pigmentation, aerial hypha formation and sporulation. They also displayed characteristic metabolic signatures such as increased levels of cysteine, cystathionine, homocysteine, S-adenosylmethionine, S-adenosylhomocysteine while methionine and glutathione levels remained unchanged. These metabolic perturbations were associated with the over-expression of MgCBS1 involved in the reversed transsulfuration pathway that metabolizes homocysteine into cysteine and MgSAM1 and MgSAHH1 involved in the methyl cycle. This suggests a physiological adaptation of M. oryzae to metabolic defects induced by the loss of Met6, in particular an increase in homocysteine levels. Pathogenicity assays showed that MET6 null mutants were non-pathogenic on both barley and rice leaves. These mutants were defective in appressorium-mediated penetration and invasive infectious growth. These pathogenicity defects were rescued by addition of exogenous methionine and S-methylmethionine. These results show that M. oryzae cannot assimilate sufficient methionine from plant tissues and must synthesize this amino acid de novo to fulfill its sulfur amino acid requirement during infection. PMID:25856162

  18. Analysis of the Structure of the AVR1-CO39 Avirulence Locus in Virulent Rice-Infecting Isolates of Magnaporthe grisea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The AVR1-CO39 gene that came from a Magnaporthe grisea isolate from weeping lovegrass controls avirulence on the rice cultivar CO39. AVR1-CO39 was not present in the genome of the rice-infecting M. grisea isolate Guy11 from French Guyana, suggesting that the gene had been deleted. Molecular analysis...

  19. A novel inoculation method of Magnaporthe grisea for cytological observation of the infection process using intact leaf sheaths of rice plants

    Microsoft Academic Search

    Hironori Koga; Koji Dohi; Osamu Nakayachi; Masashi Mori

    2004-01-01

    A novel inoculation method of the rice blast fungus Magnaporthe grisea using intact leaf sheaths of rice plants, designated as the intact method, was devised to observe the cytological events in living tissues during infection. In leaf sheaths inoculated by using the intact method, the symptoms closely resembled those occurring in inoculated plants, and progressive steps of fungal invasion and

  20. Transcriptome Markers of Viral Persistence in Naturally-Infected Andes Virus (Bunyaviridae) Seropositive Long-Tailed Pygmy Rice Rats

    PubMed Central

    Campbell, Corey L.; Torres-Perez, Fernando; Acuna-Retamar, Mariana; Schountz, Tony

    2015-01-01

    Long-tailed pygmy rice rats (Oligoryzomys longicaudatus) are principal reservoir hosts of Andes virus (ANDV) (Bunyaviridae), which causes most hantavirus cardiopulmonary syndrome cases in the Americas. To develop tools for the study of the ANDV-host interactions, we used RNA-Seq to generate a de novo transcriptome assembly. Splenic RNA from five rice rats captured in Chile, three of which were ANDV-infected, was used to generate an assembly of 66,173 annotated transcripts, including noncoding RNAs. Phylogenetic analysis of selected predicted proteins showed similarities to those of the North American deer mouse (Peromyscus maniculatus), the principal reservoir of Sin Nombre virus (SNV). One of the infected rice rats had about 50-fold more viral burden than the others, suggesting acute infection, whereas the remaining two had levels consistent with persistence. Differential expression analysis revealed distinct signatures among the infected rodents. The differences could be due to 1) variations in viral load, 2) dimorphic or reproductive differences in splenic homing of immune cells, or 3) factors of unknown etiology. In the two persistently infected rice rats, suppression of the JAK-STAT pathway at Stat5b and Ccnot1, elevation of Casp1, RIG-I pathway factors Ppp1cc and Mff, and increased FC receptor-like transcripts occurred. Caspase-1 and Stat5b activation pathways have been shown to stimulate T helper follicular cell (TFH) development in other species. These data are also consistent with reports suggestive of TFH stimulation in deer mice experimentally infected with hantaviruses. In the remaining acutely infected rice rat, the apoptotic pathway marker Cox6a1 was elevated, and putative anti-viral factors Abcb1a, Fam46c, Spp1, Rxra, Rxrb, Trmp2 and Trim58 were modulated. Transcripts for preproenkephalin (Prenk) were reduced, which may be predictive of an increased T cell activation threshold. Taken together, this transcriptome dataset will permit rigorous examination of rice rat-ANDV interactions and may lead to better understanding of virus ecology. PMID:25856432

  1. INITIAL SURVEY FOR SPIROPLASMA CITRI, A LEAFHOPPER-TRANSMITTED PATHOGEN INFECTING CITRUS AND OTHER CROPS IN CENTRAL CALIFORNIA.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spiroplasma citri, a phloem-limited, Gram positive prokaryote lacking a true cell wall, is the causal agent of citrus stubborn disease. The vectors of S. citri in California are reported to be leafhoppers (Homoptera: Cicadellidae) and includes the beet leafhopper, Circulifer tenellus, and Scaphytop...

  2. Characterization of the microbial community structure in Candidatus Liberibacter asiaticus-infected citrus plants treated with antibiotics in the field

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is one of the most devastating diseases of citrus worldwide. There are no effective control measures for this newly emerging and century-old disease. Previously, we reported a combination of Penicillin G and Streptomycin were effective in eliminating or suppressing the HLB bacter...

  3. Complete Nucleotide Sequence of a New Genotype of Citrus Tristeza Virus from an Isolate Having a Mixed Infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An isolate of Citrus tristeza virus (CTV) that causes severe stem pitting in grapefruits (# 3800) was used for sequencing. Analysis of the isolate revealed the presence of at least three different populations, one belonging to T30 genotype and the other two belonging to new genotypes, designated T2K...

  4. Current status of Citrus tristeza virus in Central California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Lindcove Research and Extension Center (LREC), Exeter, CA has 51 ha of citrus and is the field site and screenhouses for the University of California Citrus Clonal Protection Program (CCPP). LREC maintains a zero tolerance of Citrus tristeza virus (CTV) infected trees to protect the CCPP and re...

  5. Trailers transporting oranges to processing plants move Asian citrus psyllids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (citrus greening) is one of the most serious of citrus diseases. Movement of the disease occurs as a result of natural vector-borne infection and by movement of plant material. We demonstrate here that Diaphorina citri Kuwayama (vector of citrus greening pathogens) can be transported i...

  6. Biological Indexing of Graft Transmissible Diseases of Citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biological indexing for the detection of graft transmissible diseases of citrus is essential for maintaining a citrus certification program. Many of the graft transmissible diseases of citrus are harbored as latent infections in the scions, but when propagated on a susceptible rootstock that allow...

  7. Synthesis of RNAs Specific to Citrus Exocortis Viroid by a Fraction Rich in Nuclei from Infected Gynura aurantiaca: Examination of the Nature of the Products and Solubilization of the Polymerase-Template Complex

    Microsoft Academic Search

    RICARDO FLORES

    1989-01-01

    SUMMARY Viroid-specific polymerase activity was detected in preparations rich in nuclei from Gynura aurantiaca infected with citrus exocortis viroid (CEV). The polymerase catalysed the synthesis of several RNAs, shown to be viroid-specific since they could not be observed in control experiments with healthy plants, and they contained CEV- specific sequences most of which were of the same polarity as the

  8. CURRENT EPIDEMIOLOGICAL UNDERSTANDING OF CITRUS HUANGLONGBING

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is the most destructive citrus pathosystem worldwide. Previously known primarily from Asia and Africa it was introduced into the Western hemisphere in 2004. All infected commercial citrus industries continue to decline due to inadequate current control methods. HLB increase an...

  9. Biology and epidemiology of rice viruses.

    PubMed

    Hibino, H

    1996-01-01

    The 15 known viruses that occur in rice are rice black-streaked dwarf, rice bunchy stunt, rice dwarf, rice gall dwarf, rice giallume, rice grassy stunt, rice hoja blanca, rice necrosis mosaic, rice ragged stunt, rice stripe necrosis, rice stripe, rice transitory yellowing, rice tungro bacilliform, rice tungro spherical, and rice yellow mottle viruses. This paper describes their geographical distribution, relation to vectors, infection cycles, field dispersal, and development, and lists recorded outbreaks of the viruses. Many rice viruses have become serious problems since rice cultivation has been intensified. Double-cropping of rice using improved, photo-insensitive cultivars of short growth duration has significantly influenced the incidence of these viruses. PMID:15012543

  10. Characterization of the microbial community structure in Candidatus Liberibacter asiaticus-infected citrus plants treated with antibiotics in the field

    PubMed Central

    2013-01-01

    Background Huanglongbing (HLB) is a worldwide devastating disease of citrus. There are no effective control measures for this newly emerging but century-old disease. Previously, we reported a combination of Penicillin G and Streptomycin was effective in eliminating or suppressing the associated bacterium, ‘Candidatus Liberibacter asiaticus’ (Las). Results Here we report the bacterial composition and community structure in HLB-affected citrus plants during a growing season and while being treated with antibiotic combinations PS (Penicillin G and Streptomycin) and KO (Kasugamycin and Oxytetracycline) using the Phylochip™ G3 array. Both antibiotic treatments resulted in significantly lower Las bacterial titers (Pr<0.05) and hybridization scores. Of the 50,000+ available operational taxonomic units (OTUs) on PhyloChip™ G3, 7,028 known OTUs were present in citrus leaf midribs. These OTUs were from 58 phyla, of which five contained 100 or more OTUs, Proteobacteria (44.1%), Firmicutes (23.5%), Actinobacteria (12.4%), Bacteroidetes (6.6%) and Cyanobacteria (3.2%). In the antibiotic treated samples, the number of OTUs decreased to a total of 5,599. The over-all bacterial diversity decreased with the antibiotic treatments, as did the abundance of 11 OTUs within Proteobacteria, Firmicutes, Bacteroidetes and Planctomycetes. Within the Proteobacteria, ten OTUs representing the class ?-proteobacteria increased in abundance after four months of treatment, when the Las bacterium was at its lowest level in the HLB-affected citrus field plants. Conclusions Our data revealed that Proteobacteria was constantly the dominant bacterial phylum recovered from citrus leaf midribs, with the ?-proteobacterial and the ?-proteobacterial classes vying for prevalence. In addition, the level of bacterial diversity found in the leaf midribs of field citrus was greater than previously described. Bacterial cells in close proximity may be able to modify their microenvironment, making the composition of the microbial community an important factor in the ability of Las to cause HLB progression. A low Las level was seen as an annual fluctuation, part of the bacterial population dynamics, and as a response to the antibiotic treatments. PMID:23701743

  11. Transgenic expression in citrus of single-chain antibody fragments specific to Citrus tristeza virus confers virus resistance

    Microsoft Academic Search

    Magdalena Cervera; Olga Esteban; Maite Gil; M. Teresa Gorris; M. Carmen Martínez; Leandro Peña; Mariano Cambra

    2010-01-01

    Citrus tristeza virus (CTV) causes one of the most destructive viral diseases of citrus worldwide. Generation of resistant citrus genotypes through\\u000a genetic engineering could be a good alternative to control CTV. To study whether production of single-chain variable fragment\\u000a (scFv) antibodies in citrus could interfere and immunomodulate CTV infection, transgenic Mexican lime plants expressing two\\u000a different scFv constructs, separately and

  12. The effect of 'Candidatus Liberibacter asiaticus' infection on the proteomic profiles and nutritional status of pre-symptomatic and symptomatic grapefruit (Citrus paradisi) plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is a highly destructive citrus disease which threatens citrus production worldwide. Among three known ‘Candidatus Liberibacter’ species associated with HLB, ‘Ca. Liberibacter asiaticus’ (Las) is the most prevalent. To better understand the physiological and molecular processes in...

  13. Screening molecules for control of citrus Huanglongbing (HLB) using an optimized regeneration system for 'Candidatus Liberibacter asiaticus' infected periwinkle (Catharunthus roseus) cuttings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus huanglongbing (HLB) ( also known as citrus greening) is one of the most destructive diseases of citrus worldwide. The disease is associated with three different species of Candidatus Liberibacter, of which, ‘Ca. L. asiaticus’ (Las) is the most widely-distributed. An improved system using HLB-...

  14. Citrus Inventory

    NASA Technical Reports Server (NTRS)

    1986-01-01

    Florida's Charlotte County Property Appraiser is using an aerial color infrared mapping system for inventorying citrus trees for valuation purposes. The ACIR system has significantly reduced the time and manpower required for appraisal. Aerial photographs are taken and interpreted by a video system which makes it possible to detect changes from previous years. Potential problems can be identified. KSC's TU Office has awarded a contract to the Citrus Research and Education Center to adapt a prototype system which would automatically count trees and report totals.

  15. Citrus Inventory

    NASA Technical Reports Server (NTRS)

    1994-01-01

    An aerial color infrared (CIR) mapping system developed by Kennedy Space Center enables Florida's Charlotte County to accurately appraise its citrus groves while reducing appraisal costs. The technology was further advanced by development of a dual video system making it possible to simultaneously view images of the same area and detect changes. An image analysis system automatically surveys and photo interprets grove images as well as automatically counts trees and reports totals. The system, which saves both time and money, has potential beyond citrus grove valuation.

  16. Effect of Citrus Stubborn Disease on Navel Orange Production in a Commercial Orchard in California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The impact of citrus stubborn disease (CSD), caused by Spiroplasma citri, on citrus is not fully understood or quantified. The objective of this work was to measure the impact of S. citri infection on citrus production and assess bacterial distribution in trees differing in symptom severity. Infecte...

  17. Asian citrus psyllid viral pathogen

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A newly discovered viral pathogen of Asian citrus psyllid, AsCP, Diaphorina citri, Kuwayama (Psyllidae: Hemiptera) was classified as a Reoviridae. This virus may serve as a biological control agent for AsCP. The AsCP is an efficient vector of the plant-infecting bacterium (Candidatus Liberibacter as...

  18. Infection route of rice grassy stunt virus, a tenuivirus, in the body of its brown planthopper vector, Nilaparvata lugens (Hemiptera: Delphacidae) after ingestion of virus.

    PubMed

    Zheng, Limin; Mao, Qianzhuo; Xie, Lianhui; Wei, Taiyun

    2014-08-01

    Rice grassy stunt virus (RGSV), a tenuivirus, is transmitted by the brown planthopper (BPH), Nilaparvata lugens (Hemiptera, Delphacidae), in a persistent-propagative manner. In this study, immunofluorescence microscopy was used to investigate the infection route of RGSV in the internal organs of BPH after acquiring the virus by feeding on RGSV-infected rice plants. The sequential infection study revealed that RGSV initially infected the midgut epithelium, then crossed the basal lamina into the midgut visceral muscles, from where RGSV apparently spread into the hemolymph, then into the salivary glands of its BPH vector. The mechanism underlying this infection route of RGSV in its BPH vector may confer an advantage for the direct spread of RGSV from the initially infected epithelium to the salivary glands in BPH, contributing to efficient transmission of RGSV by its insect vector. PMID:24768845

  19. Morphology, ultrastructure, and bacteriophage infection of the helical mycoplasma-like organism (Spiroplasma citri gen. nov., sp. nov.) cultured from "stubborn" disease of citrus.

    PubMed

    Cole, R M; Tully, J G; Popkin, T J; Bové, J M

    1973-07-01

    The mycoplasma-like organism Spiroplasma citri gen. nov., sp. nov., isolated from citrus infected with "Stubborn" disease and carried in serial cultures in several media, was examined by dark-field microscopy and electron microscopy of negatively-stained and shadowed preparations and of sections. It grows as motile, helical filaments in liquid, but as nonmotile, nonhelical filaments and round bodies in agar cultures. Helicity and motility are lost in old broth cultures and upon addition of a variety of negative stains, fixatives, and other solutions. No organelles accounting for motility are present, but a layer of surface projections is present on the surface of the single, bounding membrane. The mycoplasma produces a tailed, type B bacteriophage which appear to attach to the outer layer. Helical filaments are preserved in ammonium molybdate, but not in sodium phosphotungstate, and by fixation in Formalin or glutaraldehyde made up in medium, but not by osmium nor by glutaraldehyde in cacodylate buffer. This mycoplasma appears similar to the noncultured helical microorganism in corn stunt-diseased tissues and is probably a representative of a new group of mycoplasmas which are in possession of surface projections, rotary motility, and bacteriophage infection. PMID:4123916

  20. DISTANCE OF SPREAD OF ASIAN CITRUS CANKER FROM SOURCE OF INFECTION IN COMMERCIAL PLANTINGS IN SAO PAULO, BRAZIL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Xanthomonas axonopodis pv. citri (Xac)-infected trees continued to occur in São Paulo commercial plantings previously subjected to eradication, indicating that removing all trees within a 30-m radius of known Xac-infected trees was insufficient to eradicate the disease within infected orchards. Pos...

  1. Morphological and molecular characterization of Magnaporthe oryzae (fungus) from infected rice leaf samples

    NASA Astrophysics Data System (ADS)

    Muni, Nurulhidayah Mat; Nadarajah, Kalaivani

    2014-09-01

    Magnaporthe oryzae is a plant-pathogenic fungus that causes a serious disease affecting rice called rice blast. Outbreaks of rice blast have been a threat to the global production of rice. This fungal disease is estimated to cause production losses of US55 million each year in South and Southeast Asia. It has been used as a primary model for elucidating various aspects of the host-pathogen interaction with its host. We have isolated five isolates of Magnaporthe oryzae from diseased leaf samples obtained from the field at Kompleks Latihan MADA, Kedah, Malaysia. We have identified the isolates using morphological and microscopic studies on the fungal spores and the lesions on the diseased leaves. Amplification of the internal transcribed spacer (ITS) was carried out with universal primers ITS1 and ITS4. The sequence of each isolates showed at least 99% nucleotide identity with the corresponding sequence in GenBank for Magnaporthe oryzae.

  2. Rice blast disease in Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice is an important agricultural commodity in Texas, with an economic impact of more than $1 billion annually. Rice blast, caused by Magnaporthe oryzae, is one of the most devastating diseases in rice. Texas Rice Belt provides a warm, humid climate favorable for the infection and reproduction of M....

  3. Phylogenomic analysis uncovers the evolutionary history of nutrition and infection mode in rice blast fungus and other Magnaporthales

    PubMed Central

    Luo, Jing; Qiu, Huan; Cai, Guohong; Wagner, Nicole E.; Bhattacharya, Debashish; Zhang, Ning

    2015-01-01

    The order Magnaporthales (Ascomycota, Fungi) includes devastating pathogens of cereals, such as the rice blast fungus Pyricularia (Magnaporthe) oryzae, which is a model in host-pathogen interaction studies. Magnaporthales also includes saprotrophic species associated with grass roots and submerged wood. Despite its scientific and economic importance, the phylogenetic position of Magnaporthales within Sordariomycetes and the interrelationships of its constituent taxa, remain controversial. In this study, we generated novel transcriptome data from 21 taxa that represent key Magnaporthales lineages of different infection and nutrition modes and phenotypes. Phylogenomic analysis of >200 conserved genes allowed the reconstruction of a robust Sordariomycetes tree of life that placed the monophyletic group of Magnaporthales sister to Ophiostomatales. Among Magnaporthales, three major clades were recognized: 1) an early diverging clade A comprised of saprotrophs associated with submerged woods; 2) clade B that includes the rice blast fungus and other pathogens that cause blast diseases of monocot plants. These species infect the above-ground tissues of host plants using the penetration structure, appressorium; and 3) clade C comprised primarily of root-associated species that penetrate the root tissue with hyphopodia. The well-supported phylogenies provide a robust framework for elucidating evolution of pathogenesis, nutrition modes, and phenotypic characters in Magnaporthales. PMID:25819715

  4. Spatial uncoupling of mitosis and cytokinesis during appressorium-mediated plant infection by the rice blast fungus Magnaporthe oryzae.

    PubMed

    Saunders, Diane G O; Dagdas, Yasin F; Talbot, Nicholas J

    2010-07-01

    To infect plants, many pathogenic fungi develop specialized infection structures called appressoria. Here, we report that appressorium development in the rice blast fungus Magnaporthe oryzae involves an unusual cell division, in which nuclear division is spatially uncoupled from the site of cytokinesis and septum formation. The position of the appressorium septum is defined prior to mitosis by formation of a heteromeric septin ring complex, which was visualized by spatial localization of Septin4:green fluorescent protein (GFP) and Septin5:GFP fusion proteins. Mitosis in the fungal germ tube is followed by long-distance nuclear migration and rapid formation of an actomyosin contractile ring in the neck of the developing appressorium, at a position previously marked by the septin complex. By contrast, mutants impaired in appressorium development, such as Deltapmk1 and DeltacpkA regulatory mutants, undergo coupled mitosis and cytokinesis within the germ tube. Perturbation of the spatial control of septation, by conditional mutation of the SEPTATION-ASSOCIATED1 gene of M. oryzae, prevented the fungus from causing rice blast disease. Overexpression of SEP1 did not affect septation during appressorium formation, but instead led to decoupling of nuclear division and cytokinesis in nongerminated conidial cells. When considered together, these results indicate that SEP1 is essential for determining the position and frequency of cell division sites in M. oryzae and demonstrate that differentiation of appressoria requires a cytokinetic event that is distinct from cell divisions within hyphae. PMID:20639448

  5. Phylogenomic analysis uncovers the evolutionary history of nutrition and infection mode in rice blast fungus and other Magnaporthales.

    PubMed

    Luo, Jing; Qiu, Huan; Cai, Guohong; Wagner, Nicole E; Bhattacharya, Debashish; Zhang, Ning

    2015-01-01

    The order Magnaporthales (Ascomycota, Fungi) includes devastating pathogens of cereals, such as the rice blast fungus Pyricularia (Magnaporthe) oryzae, which is a model in host-pathogen interaction studies. Magnaporthales also includes saprotrophic species associated with grass roots and submerged wood. Despite its scientific and economic importance, the phylogenetic position of Magnaporthales within Sordariomycetes and the interrelationships of its constituent taxa, remain controversial. In this study, we generated novel transcriptome data from 21 taxa that represent key Magnaporthales lineages of different infection and nutrition modes and phenotypes. Phylogenomic analysis of >200 conserved genes allowed the reconstruction of a robust Sordariomycetes tree of life that placed the monophyletic group of Magnaporthales sister to Ophiostomatales. Among Magnaporthales, three major clades were recognized: 1) an early diverging clade A comprised of saprotrophs associated with submerged woods; 2) clade B that includes the rice blast fungus and other pathogens that cause blast diseases of monocot plants. These species infect the above-ground tissues of host plants using the penetration structure, appressorium; and 3) clade C comprised primarily of root-associated species that penetrate the root tissue with hyphopodia. The well-supported phylogenies provide a robust framework for elucidating evolution of pathogenesis, nutrition modes, and phenotypic characters in Magnaporthales. PMID:25819715

  6. Comparative Proteomic Analysis Reveals the Cross-Talk between the Responses Induced by H2O2 and by Long-Term Rice Black-Streaked Dwarf Virus Infection in Rice

    PubMed Central

    Xu, Qiufang; Ni, Haiping; Chen, Qingqing; Sun, Feng; Zhou, Tong; Lan, Ying; Zhou, Yijun

    2013-01-01

    Hydrogen peroxide (H2O2) could be produced during the plant-virus compatible interaction. However, the cell responses regulated by the enhanced H2O2 in virus infected plant are largely unknown. To make clear the influence of Rice black-streaked dwarf virus (RBSDV) infection on H2O2 accumulation, we measured the content of H2O2 and found the H2O2 level was increased in rice seedlings inoculated with RBSDV. To reveal the responses initiated by the enhanced H2O2 during plant-virus interaction, the present study investigated the global proteome changes of rice under long-term RBSDV infection. Approximately 1800 protein spots were detected on two-dimensional electrophoresis (2-DE) gels. Among them, 72 spots were found differently expressed, of which 69 spots were successfully identified by MALDI-TOF/TOF-MS. Furthermore, the differentially expressed proteins induced by RBSDV infection were compared to that induced by H2O2. 19 proteins corresponding to 37 spots, which were differentially expressed under RBSDV infection, were observed differentially expressed under H2O2 stress as well. These overlapping responsive proteins are mainly related to photosynthesis, redox homeostasis, metabolism, energy pathway, and cell wall modification. The increased H2O2 in RBSDV infected plant may produce an oxidative stress, impair photosynthesis, disturb the metabolism, and eventually result in abnormal growth. The data provide a new understanding of the pivotal role of H2O2 in rice-RBSDV compatible interaction. PMID:24312331

  7. Molecular cloning and differential expression of an gamma-aminobutyrate transaminase gene, OsGABA-T, in rice (Oryza sativa) leaves infected with blast fungus.

    PubMed

    Wu, Chunxia; Zhou, Shanyue; Zhang, Quan; Zhao, Wensheng; Peng, Youliang

    2006-11-01

    gamma-Aminobutyrate transaminase (GABA-T) catalyzes the conversion of GABA to succinic semialdehyde. Using differential display PCR and cDNA library screening, a full-length GABA-T cDNA (OsGABA-T) was isolated from rice (Oryza sativa) leaves infected with an incompatible race of Magnaporthe grisea. The deduced amino acid sequence comprises 483 amino acid residues and shares 85-69% identity with GABA-T sequences from other plants. OsGABA-T expression is induced by blast fungus infection, mechanical wounding and ultraviolet radiation in rice leaves and is not detected in normal rice organs. This gene is also induced by defense signal molecules such as salicylic acid and abscisic acid, but not by jasmonic acid. Our data suggest that OsGABA-T (GABA shunt) may play a role in restricting the levels of cell death during the host-pathogen interaction. PMID:16896530

  8. Nutritional deficiency in citrus with symptoms of citrus variegated chlorosis disease.

    PubMed

    Silva-Stenico, M E; Pacheco, F T H; Pereira-Filho, E R; Rodrigues, J L M; Souza, A N; Etchegaray, A; Gomes, J E; Tsai, S M

    2009-08-01

    It is well known that citrus plants that have been infected by Xylella fastidiosa display nutritional deficiencies, probably caused by production of extracellular polymers by the bacteria that block normal nutrient flow through the xylem. The aim of this work was to study the mineral composition of specific foliar areas in different stages of infection in citrus. Thus, the concentrations of macro and micronutrients in leaves of citrus infected by X. fastidiosa were measured. Samples from four infected citrus orchards in the State of São Paulo, Brazil, were respectively collected from Santa Rita do Passa Quatro, Neves Paulista, Gavião Peixoto and Paraíso counties. The presence of X. fastidiosa in leaves was confirmed by polymerase chain reaction (PCR) using specific PCR primers. To understand the variation in leaf-nutrient content in citrus plants, we used foliar nutrient values from control (non-symptomatic) plants as a reference. Chemometric analysis showed that the deficiency of P and K in symptomatic trees for all orchards and high concentrations of Fe, Mn and Zn were observed in chlorotic areas, although other studies revealed deficiency of zinc in leaves. This is the first report showing that a correlation between chlorotic citrus leaf and higher concentrations of Fe, Mn and Zn are observed when infected and healthy plants were compared. PMID:19802445

  9. Inland valley rice production systems and malaria infection and disease in the forest region of western Côte d’Ivoire

    PubMed Central

    2013-01-01

    Background This study aimed to determine the epidemiological impact of rice cultivation in inland valleys on malaria in the forest region of western Côte d’Ivoire. The importance of malaria was compared in terms of prevalence and parasite density of infections and also in terms of clinical malaria incidence between three agro-ecosystems: (i) uncultivated inland valleys, (R0), (ii) inland valleys with one annual rice cultivation in the rainy season, (R1) and (iii) developed inland valleys with two annual rice cultivation cycles, (R2). Methods Between May 1998 and March 1999, seven villages of each agro-ecosystem (R0, R1 and R2) were randomly selected among villages pooled by farming system. In these 21 villages, a total of 1,900 people of all age groups were randomly selected and clinically monitored during one year. Clinical and parasitological information was obtained by active case detection of malaria episodes carried out during eight periods of five consecutive days scheduled at six weekly intervals and by cross-sectional surveys. Results Plasmodium falciparum was the principal parasite observed in the three agro-ecosystems. A level of holoendemicity of malaria was observed in the three agro-ecosystems with more than 75% of children less than 12 months old infected. Geometric mean parasite density in asymptomatic persons varied between 180 and 206 P. falciparum asexual forms per ?L of blood and was associated with season and with age, but not with farming system. The mean annual malaria incidence rate reached 0.7 (95% IC 0.5-0.9) malaria episodes per person in R0, 0.7 (95% IC 0.6-0.9) in R1 and 0.6 (95% IC 0.5-0.7) in R2. The burden of malaria was the highest among children under two years of age, with at least four attacks by person-year. Then malaria incidence decreased by half in the two to four-year age group. From the age of five years, the incidence was lower than one attack by person-year. Malaria incidence varied with season with more cases in the rainy season than in the dry season but not with farming system. Conclusion In the forest area of western Côte d’Ivoire, inland valley rice cultivation was not significantly associated with malaria burden. PMID:23841911

  10. Distinctively variable sequence-based nuclear DNA markers for multilocus phylogeography of the soybean-and rice-infecting fungal pathogen

    E-print Network

    McDonald, Bruce

    , Brazil. 2 Department of Plant Pathology, University of Minnesota, St. Paul, MN, USA. 3 Departamento de, SP, Brazil. 4 Swiss Federal of Technology Zurich, Institute of Integrative Biology, Plant Pathology infecting rice and soybean worldwide. The strat- egy was based on sequencing of cloned genomic DNA fragments

  11. REPEATABILITY AND COMPARISION OF IMAGE ANALYSIS AND VISUAL ASSESSMENT FOR DISEASE ASSESSMENT OF CITRUS CANKER

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker, a disease of several citrus species, is caused by the bacterial pathogen Xanthomonas axonopodis pv citri (Xac). The disease is of concern in several wet tropical and subtropical citrus growing regions as infection results in yield loss and severely blemished fruit unsuitable for the f...

  12. Dramatic Change in Citrus tristeza virus populations in the Dominican Republic

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus tristeza virus (CTV) is the most destructive viral pathogen of citrus and has been an important concern for the citrus industry in the Dominican Republic. Earlier studies documented widespread distribution of mild isolates of the T30 genotype, which caused no disease in the infected trees, an...

  13. Complete Genome sequence of citrus huanglongbing bacterium, ‘Candidatus Liberibacter asiaticus’ obtained through metagenomics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus huanglongbing (HLB) is the most destructive disease of citrus worldwide. It is spread by the citrus psyllids (Diaphorina citri and Trioza erytreae), and is associated with low-titer, phloem-limited infections by any of the three uncultured species of a-Proteobacteria: 'Candidatus Liberibact...

  14. Interactions between Citrus Cachexia Viroid and Closely Related Sequence Variants May Impair Expression of Cachexia Symptoms

    E-print Network

    Perreault, Jean-Pierre

    401 Interactions between Citrus Cachexia Viroid and Closely Related Sequence Variants May Impair Fruitiers Station d'Appui de la Manouba Tunis Tunisie Keywords: citrus, viroid, cachexia, HSVd, interference infected citrus tree of the variety `Clementinier' in Tunisia. One of the variants (HSVd Tun/cl3) had

  15. Citrus Stubborn Severity is Associated with Spiroplasma Citri Titer but Not with Bacterial Genotype.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The impact of citrus stubborn disease (CSD), caused by Spiroplasma citri, on citrus production is associated with symptom severity of infected citrus trees. To assess whether symptom severity was associated with spiroplasma titer in the plant, 58 S. citri strains were cultivated from severely and mi...

  16. The MET13 Methylenetetrahydrofolate Reductase Gene Is Essential for Infection-Related Morphogenesis in the Rice Blast Fungus Magnaporthe oryzae

    PubMed Central

    Wang, Hong; Wang, Congcong; Li, Ya; Yue, Xiaofeng; Ma, Zhonghua; Talbot, Nicholas J.; Wang, Zhengyi

    2013-01-01

    Methylenetetrahydrofolate reductases (MTHFRs) play a key role in the biosynthesis of methionine in both prokaryotic and eukaryotic organisms. In this study, we report the identification of a novel T-DNA-tagged mutant WH672 in the rice blast fungus Magnaporthe oryzae, which was defective in vegetative growth, conidiation and pathogenicity. Analysis of the mutation confirmed a single T-DNA insertion upstream of MET13, which encodes a 626-amino-acid protein encoding a MTHFR. Targeted gene deletion of MET13 resulted in mutants that were non-pathogenic and significantly impaired in aerial growth and melanin pigmentation. All phenotypes associated with ?met13 mutants could be overcome by addition of exogenous methionine. The M. oryzae genome contains a second predicted MTHFR-encoding gene, MET12. The deduced amino acid sequences of Met13 and Met12 share 32% identity. Interestingly, ?met12 mutants produced significantly less conidia compared with the isogenic wild-type strain and grew very poorly in the absence of methionine, but were fully pathogenic. Deletion of both genes resulted in ?met13?met12 mutants that showed similar phenotypes to single ?met13 mutants. Taken together, we conclude that the MTHFR gene, MET13, is essential for infection-related morphogenesis by the rice blast fungus M. oryzae. PMID:24116181

  17. Discovery of a viral pathogen in the Asian citrus psyllid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We used a Metagenomics approach and discovered an insect-infecting virus in adult Asian citrus psyllids in Florida. Though wide spread in nature, this is the first report of a Fijivirus in North America. The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is a small insect tha...

  18. Citrus viroid II variants associated with ‘Gummy Bark’ disease

    Microsoft Academic Search

    N. önelge; A. Cinar; J. A. Szychowski; G. Vidalakis; J. S. Semancik

    2004-01-01

    A viroid etiology for citrus gummy bark (CGB) disease of sweet orange is supported by the similarity of symptom expression to cachexia disease of mandarins and tangelos caused by the hop stunt viroid (HSVd) related citrus viroid II (CVd-II), as well as the detection of CVd-II variants in CGB infected Washington navel and Dörtyol sweet orange, a Turkish cultivar. A

  19. Interactions of citrus variegated chlorosis (CVC) with endophytic bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus variegated chlorosis (CVC), is a disease of sweet orange [Citrus sinensis (L.)], is caused by Xylella fastidiosa subsp. pauca, a phytopathogenic bacterium that has been shown to infect all sweet orange cultivars. Xylella fastidiosa is a fastidious Gram negative, xylem-limited bacterium which ...

  20. Diversity of endophytic bacterial populations and their interaction with Xylella fastidiosa in citrus plants

    Microsoft Academic Search

    Welington L. Araujo; Joelma Marcon; Walter Maccheroni; Elsas van J. D; Vuurde van J. W. L; Azevedo de J. L

    2002-01-01

    Citrus variegated chlorosis (CVC) is caused by Xylella fastidiosa, a phytopathogenic bacterium that can infect all Citrus sinensis cultivars. The endophytic bacterial communities of healthy, resistant, and CVC-affected citrus plants were studied by using cultivation as well as cultivation-independent techniques. The endophytic communities were assessed in surface-disinfected citrus branches by plating and denaturing gradient gel electrophoresis (DGGE). Dominant isolates were

  1. Expression of the rice hoja blanca virus (RHBV) non-structural protein 3 (NS3) in Escherichia coli and its in situ localization in RHBV-infected rice tissues.

    PubMed

    Muñoz, Miguel; Bolaños, Isela; Arrieta-Espinoza, Griselda; Espinoza, Ana M

    2004-09-01

    The non-structural NS3 protein gene from the rice hoja blanca virus (RHBV) was fused to the glutathione-S-transferase carboxilic end and expressed in Escherichia coli strain JM83. Large quantities of fusion protein were produced in insoluble form. The fusion protein was fractionated in SDS-PAGE and purified by electroelution, polyclonal antibodies were raised in rabbit and the antiserum was absorbed with bacterial crude extract. A band of similar size as that of NS3 protein was observed in Western blots using extracts from RHBV-infected rice plants. Immunoelectron microscopy with colloidal gold-labeled antibodies against NS3 protein and the viral nucleocapsid protein revealed in situ accumulation of NS3 protein in the cytoplasm but not in the viral inclusion bodies, vacuoles or chloroplasts of RHBV-infected plants, following the same pattern of distribution as the RHBV nucleocapsid protein. PMID:17361569

  2. Silicon enhances photochemical efficiency and adjusts mineral nutrient absorption in Magnaporthe oryzae infected rice plants

    Microsoft Academic Search

    Dan Gao; Kunzheng Cai; Jining Chen; Shiming Luo; Rensen Zeng; Jianyuan Yang; Xiaoyuan Zhu

    2011-01-01

    Silicon (Si) has been verified to play an important role in enhancing plant resistance against pathogens, but the exact mechanisms\\u000a remain unclear. Two near-isogenic lines of rice (Oryza sativa L.), CO39 (blast susceptible), and C101LAC (Pi-1) (blast resistant), were hydroponically grown to study the effects of exogenous silicon application on the changes of disease\\u000a incidence, mineral nutrient concentrations, chlorophyll content,

  3. Gene expression in Citrus sinensis fruit tissues harvested from huanglongbing-infected trees: comparison with girdled fruit.

    PubMed

    Liao, Hui-Ling; Burns, Jacqueline K

    2012-05-01

    Distribution of viable Candidatus Liberibacter asiaticus (CaLas) in sweet orange fruit and leaves ('Hamlin' and 'Valencia') and transcriptomic changes associated with huanglongbing (HLB) infection in fruit tissues are reported. Viable CaLas was present in most fruit tissues tested in HLB trees, with the highest titre detected in vascular tissue near the calyx abscission zone. Transcriptomic changes associated with HLB infection were analysed in flavedo (FF), vascular tissue (VT), and juice vesicles (JV) from symptomatic (SY), asymptomatic (AS), and healthy (H) fruit. In SY 'Hamlin', HLB altered the expression of more genes in FF and VT than in JV, whereas in SY 'Valencia', the number of genes whose expression was changed by HLB was similar in these tissues. The expression of more genes was altered in SY 'Valencia' JV than in SY 'Hamlin' JV. More genes were also affected in AS 'Valencia' FF and VT than in AS 'Valencia' JV. Most genes whose expression was changed by HLB were classified as transporters or involved in carbohydrate metabolism. Physiological characteristics of HLB-infected and girdled fruit were compared to differentiate between HLB-specific and carbohydrate metabolism-related symptoms. SY and girdled fruit were smaller than H and ungirdled fruit, respectively, with poor juice quality. However, girdling did not cause misshapen fruit or differential peel coloration. Quantitative PCR analysis indicated that many selected genes changed their expression significantly in SY flavedo but not in girdled flavedo. Mechanisms regulating development of HLB symptoms may lie in the host disease response rather than being a direct consequence of carbohydrate starvation. PMID:22407645

  4. Gene expression in Citrus sinensis fruit tissues harvested from huanglongbing-infected trees: comparison with girdled fruit

    PubMed Central

    Liao, Hui-Ling; Burns, Jacqueline K.

    2012-01-01

    Distribution of viable Candidatus Liberibacter asiaticus (CaLas) in sweet orange fruit and leaves (‘Hamlin’ and ‘Valencia’) and transcriptomic changes associated with huanglongbing (HLB) infection in fruit tissues are reported. Viable CaLas was present in most fruit tissues tested in HLB trees, with the highest titre detected in vascular tissue near the calyx abscission zone. Transcriptomic changes associated with HLB infection were analysed in flavedo (FF), vascular tissue (VT), and juice vesicles (JV) from symptomatic (SY), asymptomatic (AS), and healthy (H) fruit. In SY ‘Hamlin’, HLB altered the expression of more genes in FF and VT than in JV, whereas in SY ‘Valencia’, the number of genes whose expression was changed by HLB was similar in these tissues. The expression of more genes was altered in SY ‘Valencia’ JV than in SY ‘Hamlin’ JV. More genes were also affected in AS ‘Valencia’ FF and VT than in AS ‘Valencia’ JV. Most genes whose expression was changed by HLB were classified as transporters or involved in carbohydrate metabolism. Physiological characteristics of HLB-infected and girdled fruit were compared to differentiate between HLB-specific and carbohydrate metabolism-related symptoms. SY and girdled fruit were smaller than H and ungirdled fruit, respectively, with poor juice quality. However, girdling did not cause misshapen fruit or differential peel coloration. Quantitative PCR analysis indicated that many selected genes changed their expression significantly in SY flavedo but not in girdled flavedo. Mechanisms regulating development of HLB symptoms may lie in the host disease response rather than being a direct consequence of carbohydrate starvation. PMID:22407645

  5. Infection of barley protoplasts with rice hoja blanca tenuivirus. Brief report.

    PubMed

    Nguyen, M; Kormelink, R; Goldbach, R; Haenni, A L

    1999-01-01

    A barley protoplast system has been established that supports replication of Rice hoja blanca tenuivirus (RHBV). Following polyethylene glycol-mediated RHBV inoculation of barley protoplasts, newly synthesized viral RNAs and proteins could be detected. Time course analyses revealed de novo synthesis of genome length viral RNA4, as well as subgenomic-sized RNA4 molecules of both polarities. Two proteins, N and NS4, encoded by viral complementary RNA3 and viral RNA4 respectively, were detected by Western immunoblot analysis. The barley protoplast system thus constitutes a promising tool for in vivo studies of the sequential steps involved in the multiplication cycle of RHBV. PMID:10603179

  6. Increased resistance against citrus canker mediated by a citrus mitogen-activated protein kinase.

    PubMed

    de Oliveira, Maria Luiza Peixoto; de Lima Silva, Caio Cesar; Abe, Valéria Yukari; Costa, Marcio Gilberto Cardoso; Cernadas, Raúl Andrés; Benedetti, Celso Eduardo

    2013-10-01

    Mitogen-activated protein kinases (MAPK) play crucial roles in plant immunity. We previously identified a citrus MAPK (CsMAPK1) as a differentially expressed protein in response to infection by Xanthomonas aurantifolii, a bacterium that causes citrus canker in Mexican lime but a hypersensitive reaction in sweet oranges. Here, we confirm that, in sweet orange, CsMAPK1 is rapidly and preferentially induced by X. aurantifolii relative to Xanthomonas citri. To investigate the role of CsMAPK1 in citrus canker resistance, we expressed CsMAPK1 in citrus plants under the control of the PR5 gene promoter, which is induced by Xanthomonas infection and wounding. Increased expression of CsMAPK1 correlated with a reduction in canker symptoms and a decrease in bacterial growth. Canker lesions in plants with higher CsMAPK1 levels were smaller and showed fewer signs of epidermal rupture. Transgenic plants also revealed higher transcript levels of defense-related genes and a significant accumulation of hydrogen peroxide in response to wounding or X. citri infection. Accordingly, nontransgenic sweet orange leaves accumulate both CsMAPK1 and hydrogen peroxide in response to X. aurantifolii but not X. citri infection. These data, thus, indicate that CsMAPK1 functions in the citrus canker defense response by inducing defense gene expression and reactive oxygen species accumulation during infection. PMID:23777433

  7. Detection of rice grassy stunt tenuivirus nonstructural proteins p2, p5 and p6 from infected rice plants and from viruliferous brown planthoppers

    Microsoft Academic Search

    P. Chomchan; G. J. Miranda; Y. Shirako

    2002-01-01

    Summary.  ?The genome of Rice grassy stunt virus (RGSV) consists of 6 ambisense RNA segments, among which RNAs 1, 2, 5 and 6 are equivalent to RNAs 1, 2, 3 and 4, respectively,\\u000a of Rice stripe virus, the type species of the genus Tenuivirus. The RGSV 36-kDa nucleocapsid protein (N) is encoded on the complementary strand of RNA 5. Here, we

  8. Comparison of FTIR spectra between huanglongbing (citrus greening) and other citrus maladies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fourier Transform Infrared Spectroscopy has the ability to quickly identify the presence of specific carbohydrates in plant materials. The presence of the disease Huanglongbing(HLB) in the leaves of infected citrus plants has a distinctive spectrum that can be used to distinguish an infected plant ...

  9. Rice Diseases.

    E-print Network

    Jones, Roger K.

    1987-01-01

    constraints (particularly fuel prices) have all but eliminated this practice that served to reduce initial inoculum of many rice diseases by deep burial of sclerotia and infected crop residue. *Extension plant pathologist , The Texas A&M University System... slower to emerge may suffer reductions in stand and potential yield not encountered with varieties that emerge rapidly. Chemical seed treatment is a very cost effective way of minimizing potential damage from seedling disease. See the seed treatment...

  10. SPATIAL PATTERN ANALYSIS OF CITRUS CANKER INFECTED PLANTINGS IN SÃO PAULO BRAZIL AND IMPLICATION OF THE ASIAN LEAFMINER ON THE POTENTIAL DISPERSAL PROCESSES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Eradication of Asiatic Citrus Canker (ACC) has become increasingly difficult over the last decade following the introduction of the Asian leafminer into Brazil and Florida, which lead to changes in the eradication protocols. The present study, undertaken in Brazil, was aimed at characterizing the s...

  11. Wind speed effects on the quantity of Xanthomonas citri subsp. citri dispersed downwind from canopies of grapefruit trees infected with citrus canker

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The epidemic of citrus canker (Xanthomonas citri subsp. citri, Xcc) in Florida continues to expand since termination of the eradication program in 2006. Storms are known to be associated with disease spread, but little information exists on the interaction of fundamental physical and biological proc...

  12. SPATIAL PATTERN ANALYSIS OF CITRUS CANKER INFECTED PLANTINGS IN SAO PAULO BRAZIL AND IMPLICATION OF THE ASIAN LEAFMINER ON POTENTIAL DISPERSAL PROCESSES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Eradication of Asiatic Citrus Canker (ACC) has become increasingly difficult over the last decade following the introduction of the Asian leafminer into Brazil and Florida. This prompted epidemiological studies in both countries that resulted in changes in the eradication protocols. The objective ...

  13. Visual rating and the use of image analysis for assessing different symptoms of citrus canker on grapefruit leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker is caused by the bacterial pathogen Xanthomonas axonopodis pv citri (Xac) and infects several citrus species in wet tropical and subtropical citrus growing regions. Accurate, precise and reproducible disease assessment is needed for monitoring epidemics and disease response in breeding...

  14. An Inexpensive and Safe Experiment to Demonstrate Koch's Postulates Using Citrus Fruit

    ERIC Educational Resources Information Center

    Jakobi, Steven

    2010-01-01

    Citrus fruit (oranges, tangerines, grapefruit or lemons) purchased in a grocery store can be experimentally infected with readily-available sources of "Penicillium digitatum" to demonstrate the four basic steps of Koch's postulates, also known as proof of pathogenicity. The mould is isolated from naturally-infected citrus fruit into pure culture…

  15. Management of the Citrus Nematode, Tylenchulus semipenetrans

    PubMed Central

    Verdejo-Lucas, S.; McKenry, M. V.

    2004-01-01

    Of the many nematode species that parasitize citrus, Tylenchulus semipenetrans is the most important on a worldwide basis. Management of the citrus nematode remains problematic as no one tactic gives adequate control of the nematode. An overall management strategy must include such components as site selection, use of non-infected nursery stock, use of at lease one post-plant nematode control tactic, and careful management of other elements of the environment that may stress the trees. Nematicides continue to play a key role in management of this pest. Optimum results require careful attention to application techniques. PMID:19262822

  16. Diversity of bacteriophages infecting Xanthomonas oryzae pv. oryzae in paddy fields and its potential to control bacterial leaf blight of rice.

    PubMed

    Chae, Jong-Chan; Hung, Nguyen Bao; Yu, Sang-Mi; Lee, Ha Kyung; Lee, Yong Hoon

    2014-06-28

    Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a very serious disease in rice-growing regions of the world. In spite of their economic importance, there are no effective ways of protecting rice plants from this disease. Bacteriophages infecting Xoo affect the population dynamics of the pathogen and consequently the occurrence of the disease. In this study, we investigated the diversity, host range, and infectivity of Xoo phages, and their use as a bicontrol agent on BLB was tested. Among the 34 phages that were isolated from floodwater in paddy fields, 29 belonged to the Myoviridae family, which suggests that the dominant phage in the ecosystem was Myoviridae. The isolated phages were classified into two groups based on plaque size produced on the lawn of Xoo. In general, there was a negative relationship between plaque size and host range, and interestingly the phages having a narrow host range had low efficiency of infectivity. The deduced protein sequence analysis of htf genes indicated that the gene was not a determinant of host specificity. Although the difference in host range and infectivity depending on morphotype needs to be addressed, the results revealed deeper understanding of the interaction between the phages and Xoo strains in floodwater and damp soil environments. The phage mixtures reduced the occurrence of BLB when they were treated with skim milk. The results indicate that the Xoo phages could be used as an alternative control method to increase the control efficacy and reduce the use of agrochemicals. PMID:24651644

  17. Abundance of citrus leafminer larvae on citrus and citrus-related germplasm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), is a key pest in most citrus growing regions worldwide. Adult citrus leafminers oviposit primarily on young elongating flush of citrus as well as other Rutaceae and some ornamental plants. Larvae feed on the epiderm...

  18. Defective RNA Molecules Associated with Citrus Tristeza Virus

    Microsoft Academic Search

    Munir Mawass; Alexander V. Karasev; Elzbieta Mietkiewska; Ron Gafny; Richard F. Lee; William O. Dawson; Moshe Bar-Joseph

    1995-01-01

    Preparations of single-stranded (ss) RNA extracted from particles of the Israeli VT strain of citrus tristeza virus (CTV-VT), and ss- and double-stranded (ds) RNA preparations extracted from infected Alemow (Citrus macrophylla) plants, contained a population of molecules with features that suggest that they are defective RNAs. The prototype of 2424 nt was cloned and sequenced and was found to be

  19. Modeling huanglongbing transmission within a citrus tree

    PubMed Central

    Chiyaka, Christinah; Singer, Burton H.; Halbert, Susan E.; Morris, J. Glenn; van Bruggen, Ariena H. C.

    2012-01-01

    The citrus disease huanglongbing (HLB), associated with an uncultured bacterial pathogen, is threatening the citrus industry worldwide. A mathematical model of the transmission of HLB between its psyllid vector and citrus host has been developed to characterize the dynamics of the vector and disease development, focusing on the spread of the pathogen from flush to flush (a newly developing cluster of very young leaves on the expanding terminal end of a shoot) within a tree. This approach differs from that of prior models for vector-transmitted plant diseases where the entire plant is the unit of analysis. Dynamics of vector and host populations are simulated realistically as the flush population approaches complete infection. Model analysis indicates that vector activity is essential for initial infection but is not necessary for continued infection because infection can occur from flush to flush through internal movement in the tree. Flush production, within-tree spread, and latent period are the most important parameters influencing HLB development. The model shows that the effect of spraying of psyllids depends on time of initial spraying, frequency, and efficacy of the insecticides. Similarly, effects of removal of symptomatic flush depend on the frequency of removal and the time of initiation of this practice since the start of the epidemic. Within-tree resistance to spread, possibly affected by inherent or induced resistance, is a major factor affecting epidemic development, supporting the notion that alternate routes of transmission besides that by the vector can be important for epidemic development. PMID:22783015

  20. RICE CRICKET CLUB Rice University

    E-print Network

    Mellor-Crummey, John

    RICE CRICKET CLUB Rice University 6100 Main St, Houston, TX-77005 www.ruf.rice.edu/~rcc Email: rcc CRICKET CLUB which includes practice sessions, games and social gatherings conducted on and off the Rice. Every member must pay their annual dues of $________ towards membership of the Rice Cricket Club

  1. Citrus greening detection using airborne hyperspectral and multispectral imaging techniques

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hyperspectral imaging can provide unique spectral signatures for diseased vegetation. Airborne multispectral and hyperspectral imaging can be used to detect potentially infected trees over a large area for rapid detection of infected zones. This paper proposes a method to detect the citrus greening...

  2. High incidence of preharvest colonization of huanglongbing-symptomatic Citrus sinensis fruit by Lasiodiplodia theobromae (Diplodia natalensis) and exacerbation of postharvest fruit decay by that fungus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB), presumably caused by bacterium Candidatus Liberibacter asiaticus (CLas), is a devastating citrus disease associated with excessive pre-harvest fruit drop. Lasiodiplodia theobromae (Diplodia) is the causal organism of citrus stem end rot (SER). The pathogen infects citrus fruit ...

  3. Ectopic expression of ubiquitin-conjugating enzyme gene from wild rice, OgUBC1, confers resistance against UV-B radiation and Botrytis infection in Arabidopsis thaliana

    SciTech Connect

    Jeon, En Hee; Pak, Jung Hun; Kim, Mi Jin; Kim, Hye Jeong [Department of Genetic Engineering, Dong-A University, Busan 604-714 (Korea, Republic of)] [Department of Genetic Engineering, Dong-A University, Busan 604-714 (Korea, Republic of); Shin, Sang Hyun [National Crop Experiment Station, Rural Development Administration, Suwon 441-100 (Korea, Republic of)] [National Crop Experiment Station, Rural Development Administration, Suwon 441-100 (Korea, Republic of); Lee, Jai Heon; Kim, Doh Hoon; Oh, Ju Sung [Department of Genetic Engineering, Dong-A University, Busan 604-714 (Korea, Republic of)] [Department of Genetic Engineering, Dong-A University, Busan 604-714 (Korea, Republic of); Oh, Boung-Jun [BioControl Center, Jeonnam 516-942 (Korea, Republic of)] [BioControl Center, Jeonnam 516-942 (Korea, Republic of); Jung, Ho Won, E-mail: hwjung@dau.ac.kr [Department of Genetic Engineering, Dong-A University, Busan 604-714 (Korea, Republic of); Chung, Young Soo, E-mail: chungys@dau.ac.kr [Department of Genetic Engineering, Dong-A University, Busan 604-714 (Korea, Republic of)

    2012-10-19

    Highlights: Black-Right-Pointing-Pointer We isolated a novel E2 ubiquitin-conjugating enzyme from leaves of wild rice plants. Black-Right-Pointing-Pointer The OgUBC1 was highly expressed in leaves treated with SA and UV-B radiation. Black-Right-Pointing-Pointer The recombinant OgUBC1 has an enzymatic activity of E2 in vitro. Black-Right-Pointing-Pointer The OgUBC1 could protect disruption of plant cells by UV-B radiation. Black-Right-Pointing-Pointer OgUBC1 confers disease resistance and UV-B tolerance in transgenic Arabidopsis plants. -- Abstract: A previously unidentified gene encoding ubiquitin-conjugating enzyme was isolated from leaves of wild rice plant treated with wounding and microbe-associated molecular patterns. The OgUBC1 gene was composed of 148 amino acids and contained a typical active site and 21 ubiquitin thioester intermediate interaction residues and 4 E3 interaction residues. Both exogenous application of salicylic acid and UV-B irradiation triggered expression of OgUBC1 in leaves of wild rice. Recombinant OgUBC1 proteins bound to ubiquitins in vitro, proposing that the protein might act as E2 enzyme in planta. Heterologous expression of the OgUBC1 in Arabidopsis thaliana protected plants from cellular damage caused by an excess of UV-B radiation. A stable expression of chalcone synthase gene was detected in leaves of OgUBC1-expressing Arabidopsis, resulting in producing higher amounts of anthocyanin than those in wild-type Col-0 plants. Additionally, both pathogenesis-related gene1 and 5 were transcribed in the transgenic Arabidopsis in the absence of pathogen infection. The OgUBC1-expressing plants were resistant to the infection of Botrytis cinerea. Taken together, we suggested that the OgUBC1 is involved in ubiquitination process important for cellular response against biotic and abiotic stresses in plants.

  4. Characterisation of Four LIM Protein-Encoding Genes Involved in Infection-Related Development and Pathogenicity by the Rice Blast Fungus Magnaporthe oryzae

    PubMed Central

    Li, Ya; Yue, Xiaofeng; Que, Yawei; Yan, Xia; Ma, Zhonghua; Talbot, Nicholas J.; Wang, Zhengyi

    2014-01-01

    LIM domain proteins contain contiguous double-zinc finger domains and play important roles in cytoskeletal re-organisation and organ development in multi-cellular eukaryotes. Here, we report the characterization of four genes encoding LIM proteins in the rice blast fungus Magnaporthe oryzae. Targeted gene replacement of either the paxillin-encoding gene, PAX1, or LRG1 resulted in a significant reduction in hyphal growth and loss of pathogenicity, while deletion of RGA1 caused defects in conidiogenesis and appressorium development. A fourth LIM domain gene, LDP1, was not required for infection-associated development by M. oryzae. Live cell imaging revealed that Lrg1-GFP and Rga1-GFP both localize to septal pores, while Pax1-GFP is present in the cytoplasm. To explore the function of individual LIM domains, we carried out systematic deletion of each LIM domain, which revealed the importance of the Lrg1-LIM2 and Lrg1-RhoGAP domains for Lrg1 function and overlapping functions of the three LIM domains of Pax1. Interestingly, deletion of either PAX1 or LRG1 led to decreased sensitivity to cell wall-perturbing agents, such as Congo Red and SDS (sodium dodecyl sulfate). qRT-PCR analysis demonstrated the importance of both Lrg1 and Pax1 to regulation of genes associated with cell wall biogenesis. When considered together, our results indicate that LIM domain proteins are key regulators of infection-associated morphogenesis by the rice blast fungus. PMID:24505448

  5. THE ENDOPHYTE CURTOBACTERIUM FLACCUMFACIENS REDUCES SYMPTOMS CAUSED BY XYLELLA FASTIDIOSA IN CATHARANTHUS ROSEUSAN ENDOPHYTIC BACTERIUM FROM CITRUS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus variegated chlorosis (CVC) is a disease of sweet orange (Citrus sinensis (L.)) caused by Xylella fastidiosa subsp. pauca, a phytopathogenic bacterium that can infect all sweet orange cultivars. Sweet orange trees are sometimes observed to be infected by Xylella fastidiosa without showing seve...

  6. Genome sequence of Candidatus Liberibacter asiaticus, the casual agent of citrus huanglongbing (greening)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus huanglongbing (HLB) is one of the most devastating diseases of citrus worldwide. The disease is associated with three different species of Candidatus Liberibacter: Ca. L. asiaticus (Las), Ca. L. americanus and Ca. L. africanus. We first detected and identified Las bacterium from HLB-infected...

  7. Molecular Marker Analysis of Citrus tristeza virus (CTV) isolates from the Dominican Republic

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Samples of citrus tissue infected with Citrus tristeza virus (CTV) were collected from Persian lime, mandarin, Washington navel, Valencia or grapefruit trees from various locations in the Dominican Republic. Desiccated tissue samples were re-hydrated and virions extracted by grinding samples in buff...

  8. Characterization of complete sequences of RNA 1 and RNA 2 of citrus variegation virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus variegation virus (CVV), a member of the genus Ilarvirus, was originally isolated from citrus but was reported to infect many herbaceous plants under greenhouse conditions. The virus particles are approximately 30 nm in diameter, and are composed of coat proteins (CP) with a Mr of 26 kDa, and...

  9. Reovirus-like sequences isolated from adult Asian citrus psyllid, (Hemiptera: Psyllidae: Diaphorina citri)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Though wide spread in nature, this is the first report of a Fijivirus from North America and which was detected in a new virus host species, the Asian citrus psyllid. Few viruses have ever been reported from psyllids. We discovered an insect infecting virus in field collected Asian citrus psyllids i...

  10. Reovirus-like sequences isolated from adult Asian citrus psyllid, (Hemiptera: Psyllidae: Diaphorina citri)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Though wide spread in nature, this is the first report of a fijiviruses from North America detected in a new virus host species, the Asian citrus psyllid. Few viruses have ever been reported from psyllids. We discovered an insect infecting virus in field collected Asian citrus psyllids in Florida. T...

  11. VARIABILITY IN TRANSMISSION OF CITRUS TRISTEZA VIRUS ISOLATES FROM FLORIDA BY TOXOPTERA CITRICIDA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus tristeza virus (CTV) is an aphid transmitted plant infecting virus that continues to pose serious problems in the citriculture industries. Fifteen Florida isolates of CTV were tested for their transmissibility by the brown citrus aphid (Toxoptera citricida Kirkaldy) (BrCA). The BrCA is the ma...

  12. DIFFERENTIAL EFFECTS OF CITRUS PEEL EXTRACTS ON GROWTH OF PENICILLIUM DIGITATIUM, P. ITALICUM AND P. EXPANSUM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Most pathogenic species of Penicillium have a limited host range, suggesting unique adaptations to particular hosts. P. digitatum and P. italicum are primarily pathogens of mature citrus fruit, while P. expansum has a broad host range, but does not infect citrus. One possible basis of host specifi...

  13. Identification of defense-related genes in rice responding to challenge by Rhizoctonia solani

    Microsoft Academic Search

    Chang-Jiang Zhao; Ai-Rong Wang; Yu-Jun Shi; Liu-Qing Wang; Wen-De Liu; Zong-Hua Wang; Guo-Dong Lu

    2008-01-01

    Rice sheath blight, caused by Rhizoctonia solani is one of the major diseases of rice. The pathogen infects rice plants directly through stomata or using lobate appressoria\\u000a and hyphal masses called infection cushions. The infection structures were normally found at 36 h post-inoculation. During\\u000a infection, the pathogenesis-related genes, PR1b and PBZ1 were induced in rice plants. To identify rice genes induced

  14. Developing Transgenic Citrus for Resistance to Huanglongbing and Citrus Canker

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) and Citrus Bacterial Canker (CBC) are serious threats to citrus production, and resistant transgenic citrus is desirable. Genes for antimicrobial peptides (AMPs) with diverse promoters have been used to generate thousands of rootstock and scion transformants. D35S::D4E1 transfor...

  15. Citrus diseases with global ramifications including citrus canker and huanglongbing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although there are a number of diseases that plague citrus production worldwide, two bacterial diseases are particularly problematic. Both are of Asian origin and currently cause severe economic damage: Asiatic citrus canker (ACC) and citrus huanglongbing (HLB). Although ACC has been found in the ...

  16. Novel demonstration of RNAi in citrus reveals importance of citrus callose synthase in defence against Xanthomonas citri subsp. citri.

    PubMed

    Enrique, Ramón; Siciliano, Florencia; Favaro, María Alejandra; Gerhardt, Nadia; Roeschlin, Roxana; Rigano, Luciano; Sendin, Lorena; Castagnaro, Atilio; Vojnov, Adrian; Marano, María Rosa

    2011-04-01

    Citrus is an economically important fruit crop that is severely afflicted by citrus canker, a disease caused by the bacterial phytopathogen, Xanthomonas citri subsp. citri (Xcc). GenBank houses a large collection of Expressed Sequence Tags (ESTs) enriched with transcripts generated during the defence response against this pathogen; however, there are currently no strategies in citrus to assess the function of candidate genes. This has greatly limited research as defence signalling genes are often involved in multiple pathways. In this study, we demonstrate the efficacy of RNA interference (RNAi) as a functional genomics tool to assess the function of candidate genes involved in the defence response of Citrus limon against the citrus canker pathogen. Double-stranded RNA expression vectors, encoding hairpin RNAs for citrus host genes, were delivered to lemon leaves by transient infiltration with transformed Agrobacterium. As proof of principle, we have established silencing of citrus phytoene desaturase (PDS) and callose synthase (CalS1) genes. Phenotypic and molecular analyses showed that silencing vectors were functional not only in lemon plants but also in other species of the Rutaceae family. Using silencing of CalS1, we have demonstrated that plant cell wall-associated defence is the principal initial barrier against Xanthomonas infection in citrus plants. Additionally, we present here results that suggest that H?O? accumulation, which is suppressed by xanthan from Xcc during pathogenesis, contributes to inhibition of xanthan-deficient Xcc mutant growth either in wild-type or CalS1-silenced plants. With this work, we have demonstrated that high-throughput reverse genetic analysis is feasible in citrus. PMID:20809929

  17. CITRUS ROOTSTOCKS: THEIR CHARACTERS AND

    E-print Network

    CITRUS ROOTSTOCKS: THEIR CHARACTERS AND REACTIONS (an unpublished manuscript) ca. 1986 By W. P Library, retired Subject matter experts, digital version: Dr. Tracy Kahn, Curator, UC Citrus Variety Collection Dr. Robert Krueger, Curator, USDA-ARS National Clonal Germplasm Repository for Citrus & Dates Toni

  18. 7 CFR 301.76-2 - Regulated articles for Asian citrus psyllid and citrus greening.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 false Regulated articles for Asian citrus psyllid and citrus greening. 301.76-2 Section 301.76-2...DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Greening and Asian Citrus Psyllid §...

  19. 7 CFR 301.76-2 - Regulated articles for Asian citrus psyllid and citrus greening.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 false Regulated articles for Asian citrus psyllid and citrus greening. 301.76-2 Section 301.76-2...DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Greening and Asian Citrus Psyllid §...

  20. 7 CFR 301.76-2 - Regulated articles for Asian citrus psyllid and citrus greening.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 false Regulated articles for Asian citrus psyllid and citrus greening. 301.76-2 Section 301.76-2...DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Greening and Asian Citrus Psyllid §...

  1. 7 CFR 301.76-3 - Quarantined areas; citrus greening and Asian citrus psyllid.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Quarantined areas; citrus greening and Asian citrus psyllid. 301.76-3 Section 301.76-3...DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Greening and Asian Citrus Psyllid §...

  2. 7 CFR 301.76-3 - Quarantined areas; citrus greening and Asian citrus psyllid.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Quarantined areas; citrus greening and Asian citrus psyllid. 301.76-3 Section 301.76-3...DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Greening and Asian Citrus Psyllid §...

  3. 7 CFR 301.76-2 - Regulated articles for Asian citrus psyllid and citrus greening.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 false Regulated articles for Asian citrus psyllid and citrus greening. 301.76-2 Section 301.76-2...DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Greening and Asian Citrus Psyllid §...

  4. 7 CFR 301.76-3 - Quarantined areas; citrus greening and Asian citrus psyllid.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Quarantined areas; citrus greening and Asian citrus psyllid. 301.76-3 Section 301.76-3...DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Greening and Asian Citrus Psyllid §...

  5. 7 CFR 301.76-3 - Quarantined areas; citrus greening and Asian citrus psyllid.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 2011-01-01 false Quarantined areas; citrus greening and Asian citrus psyllid. 301.76-3 Section 301.76-3...DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Greening and Asian Citrus Psyllid §...

  6. Structure-function analysis of a CVNH-LysM lectin expressed during plant infection by the rice blast fungus Magnaporthe oryzae

    PubMed Central

    Koharudin, Leonardus M.I.; Viscomi, Arturo R.; Montanini, Barbara; Kershaw, Michael J.; Talbot, Nicholas J.; Ottonello, Simone; Gronenborn, Angela M.

    2011-01-01

    Summary The rice blast fungus Magnaporthe oryzae’s genome encodes a hypothetical protein (MGG_03307) containing a type III CVNH lectin, in which a LysM domain is inserted between individual repeats of a single CVNH domain. At present, no structural or ligand binding data is available for any type III CVNH and functional studies in natural source organisms are scarce. Here, we report NMR solution structure and functional data on MGG_03307. The structure of the CVNH/LysM module revealed that intact and functionally competent CVNH and LysM domains are present. Using NMR titrations, carbohydrate specificities for both domains were determined, and it was found that each domain behaves as an isolated unit without any inter-domain communication. Furthermore, live-cell imaging revealed a predominant localization of MGG_03307 within the appressorium, the specialized fungal cell for gaining entry into rice tissue. Our results suggest that MGG_03307 plays a role in the early stages of plant infection. PMID:21565701

  7. Differentially-expressed genes in rice infected by Xanthomonas oryzae pv. oryzae relative to a flagellin-deficient mutant reveal potential functions of flagellin in host–pathogen interactions

    PubMed Central

    2014-01-01

    Background Plants have evolved a sensitive defense response system that detects and recognizes various pathogen-associated molecular patterns (PAMPs) (e.g. flagellin) and induces immune responses to protect against invasion. Transcriptional responses in rice to PAMPs produced by Xanthomonas oryzae pv. oryzae (Xoo), the bacterial blight pathogen, have not yet been defined. Results We characterized transcriptomic responses in rice inoculated with the wildtype (WT) Xoo and flagellin-deficient mutant ?fliC through RNA-seq analysis. Digital gene expression (DGE) analysis based on Solexa/Illumina sequencing was used to investigate transcriptomic responses in 30 day-old seedlings of rice (Oryza sativa L. cv. Nipponbare). 1,680 genes were differentially-expressed (DEGs) in rice inoculated with WT relative to ?fliC; among which 1,159 genes were up-regulated and 521 were down-regulated. Expression patterns of 12 randomly-selected DEGs assayed by quantitative real time PCR (qRT-PCR) were similar to those detected by DGE analyses, confirming reliability of the DGE data. Functional annotations revealed the up-regulated DEGs are involved in the cell wall, lipid and secondary metabolism, defense response and hormone signaling, whereas the down-regulated ones are associated with photosynthesis. Moreover, 57 and 21 specifically expressed genes were found after WT and ?fliC treatments, respectively. Conclusions DEGs were identified in rice inoculated with WT Xoo relative to ?fliC. These genes were predicted to function in multiple biological processes, including the defense response and photosynthesis in rice. This study provided additional insights into molecular basis of rice response to bacterial infection and revealed potential functions of bacterial flagellin in the rice-Xoo interactions. PMID:25187853

  8. Citrus tristeza virus-host interactions

    PubMed Central

    Dawson, W. O.; Garnsey, S. M.; Tatineni, S.; Folimonova, S. Y.; Harper, S. J.; Gowda, S.

    2013-01-01

    Citrus tristeza virus (CTV) is a phloem-limited virus whose natural host range is restricted to citrus and related species. Although the virus has killed millions of trees, almost destroying whole industries, and continually limits production in many citrus growing areas, most isolates are mild or symptomless in most of their host range. There is little understanding of how the virus causes severe disease in some citrus and none in others. Movement and distribution of CTV differs considerably from that of well-studied viruses of herbaceous plants where movement occurs largely through adjacent cells. In contrast, CTV systemically infects plants mainly by long-distance movement with only limited cell-to-cell movement. The virus is transported through sieve elements and occasionally enters an adjacent companion or phloem parenchyma cell where virus replication occurs. In some plants this is followed by cell-to-cell movement into only a small cluster of adjacent cells, while in others there is no cell-to-cell movement. Different proportions of cells adjacent to sieve elements become infected in different plant species. This appears to be related to how well viral gene products interact with specific hosts. CTV has three genes (p33, p18, and p13) that are not necessary for infection of most of its hosts, but are needed in different combinations for infection of certain citrus species. These genes apparently were acquired by the virus to extend its host range. Some specific viral gene products have been implicated in symptom induction. Remarkably, the deletion of these genes from the virus genome can induce large increases in stem pitting (SP) symptoms. The p23 gene, which is a suppressor of RNA silencing and a regulator of viral RNA synthesis, has been shown to be the cause of seedling yellows (SY) symptoms in sour orange. Most isolates of CTV in nature are populations of different strains of CTV. The next frontier of CTV biology is the understanding how the virus variants in those mixtures interact with each other and cause diseases. PMID:23717303

  9. Molecular analyses of the rice tubby-like protein gene family and their response to bacterial infection

    Microsoft Academic Search

    Yanjun Kou; Deyun Qiu; Lei Wang; Xianghua Li; Shiping Wang

    2009-01-01

    Tubby-like protein family has been identified in various multicellular organisms, indicating its fundamental functions in\\u000a the organisms. However, the roles of plant tubby-like proteins are unknown. In this study, we have defined the tubby-like\\u000a protein gene (OsTLP) family with 14 members in rice. Most of the OsTLPs harbor a tubby domain in their carboxyl terminus and an F-box domain\\u000a in

  10. Annotation of gene function in citrus using gene expression information and co-expression networks

    PubMed Central

    2014-01-01

    Background The genus Citrus encompasses major cultivated plants such as sweet orange, mandarin, lemon and grapefruit, among the world’s most economically important fruit crops. With increasing volumes of transcriptomics data available for these species, Gene Co-expression Network (GCN) analysis is a viable option for predicting gene function at a genome-wide scale. GCN analysis is based on a “guilt-by-association” principle whereby genes encoding proteins involved in similar and/or related biological processes may exhibit similar expression patterns across diverse sets of experimental conditions. While bioinformatics resources such as GCN analysis are widely available for efficient gene function prediction in model plant species including Arabidopsis, soybean and rice, in citrus these tools are not yet developed. Results We have constructed a comprehensive GCN for citrus inferred from 297 publicly available Affymetrix Genechip Citrus Genome microarray datasets, providing gene co-expression relationships at a genome-wide scale (33,000 transcripts). The comprehensive citrus GCN consists of a global GCN (condition-independent) and four condition-dependent GCNs that survey the sweet orange species only, all citrus fruit tissues, all citrus leaf tissues, or stress-exposed plants. All of these GCNs are clustered using genome-wide, gene-centric (guide) and graph clustering algorithms for flexibility of gene function prediction. For each putative cluster, gene ontology (GO) enrichment and gene expression specificity analyses were performed to enhance gene function, expression and regulation pattern prediction. The guide-gene approach was used to infer novel roles of genes involved in disease susceptibility and vitamin C metabolism, and graph-clustering approaches were used to investigate isoprenoid/phenylpropanoid metabolism in citrus peel, and citric acid catabolism via the GABA shunt in citrus fruit. Conclusions Integration of citrus gene co-expression networks, functional enrichment analysis and gene expression information provide opportunities to infer gene function in citrus. We present a publicly accessible tool, Network Inference for Citrus Co-Expression (NICCE, http://citrus.adelaide.edu.au/nicce/home.aspx), for the gene co-expression analysis in citrus. PMID:25023870

  11. Insecticide sprays, natural enemy assemblages and predation on Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae).

    PubMed

    Monzo, C; Qureshi, J A; Stansly, P A

    2014-10-01

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama is considered a key citrus pest due to its role as vector of 'huanglongbing' (HLB) or citrus greening, probably the most economically damaging disease of citrus. Insecticidal control of the vector is still considered a cornerstone of HLB management to prevent infection and to reduce reinoculation of infected trees. The severity of HLB has driven implementation of intensive insecticide programs against ACP with unknown side effects on beneficial arthropod fauna in citrus agroecosystems. We evaluated effects of calendar sprays directed against this pest on natural enemy assemblages and used exclusion to estimate mortality they imposed on ACP populations in citrus groves. Predator exclusion techniques were used on nascent colonies of D. citri in replicated large untreated and sprayed plots of citrus during the four major flushing periods over 2 years. Population of spiders, arboreal ants and ladybeetles were independently assessed. Monthly sprays of recommended insecticides for control of ACP, adversely affected natural enemy populations resulting in reduced predation on ACP immature stages, especially during the critical late winter/early spring flush. Consequently, projected growth rates of the ACP population were greatest where natural enemies had been adversely affected by insecticides. Whereas, this result does not obviate the need for insecticidal control of ACP, it does indicate that even a selective regimen of sprays can impose as yet undetermined costs in terms of reduced biological control of this and probably other citrus pests. PMID:24830653

  12. Citrus Leafminer Mating Disruption

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mating disruption targets a specific pest and has no negative impact on natural enemies, the environment, or agricultural workers. A flowable wax dispenser was tested for releasing the female sex pheromone of the citrus leafminer, Phyllocnistis citrella. These dispensers are biodegradable, inexpens...

  13. Citrus and salinity

    Microsoft Academic Search

    R Storey; R. R Walker

    1998-01-01

    Citrus is a major horticultural crop worldwide and is relatively salt sensitive. Salt damage usually manifests as leaf burn and defoliation, and is associated with accumulation of toxic levels of Na+ and\\/or Cl? in leaf cells. Factors affecting tree response to salinity are documented, including salinity levels for onset and rate of yield decline in mature trees. The review is

  14. Physiological stressors and invasive plant infections alter the small RNA transcriptome of the rice blast fungus, Magnaporthe oryzae

    PubMed Central

    2013-01-01

    Background The rice blast fungus, Magnaporthe oryzae is a destructive pathogen of rice and other related crops, causing significant yield losses worldwide. Endogenous small RNAs (sRNAs), including small interfering RNAs (siRNAs) and microRNAs (miRNAs) are critical components of gene regulation in many eukaryotic organisms. Recently several new species of sRNAs have been identified in fungi. This fact along with the availability of genome sequence makes M. oryzae a compelling target for sRNA profiling. We have examined sRNA species and their biosynthetic genes in M. oryzae, and the degree to which these elements regulate fungal stress responses. To this end, we have characterized sRNAs under different physiological stress conditions, which had not yet been examined in this fungus. Results The resulting libraries are composed of more than 37 million total genome matched reads mapping to intergenic regions, coding sequences, retrotransposons, inverted, tandem, and other repeated regions of the genome with more than half of the small RNAs arising from intergenic regions. The 24 nucleotide (nt) size class of sRNAs was predominant. A comparison to transcriptional data of M. oryzae undergoing the same physiological stresses indicates that sRNAs play a role in transcriptional regulation for a small subset of genes. Support for this idea comes from generation and characterization of mutants putatively involved in sRNAs biogenesis; our results indicate that the deletion of Dicer-like genes and an RNA-Dependent RNA Polymerase gene increases the transcriptional regulation of this subset of genes, including one involved in virulence. Conclusions Various physiological stressors and in planta conditions alter the small RNA profile of the rice blast fungus. Characterization of sRNA biosynthetic mutants helps to clarify the role of sRNAs in transcriptional control. PMID:23663523

  15. Lateral organ boundaries 1 is a disease susceptibility gene for citrus bacterial canker disease

    PubMed Central

    Hu, Yang; Zhang, Junli; Jia, Hongge; Sosso, Davide; Li, Ting; Frommer, Wolf B.; Yang, Bing; White, Frank F.; Wang, Nian; Jones, Jeffrey B.

    2014-01-01

    Citrus bacterial canker (CBC) disease occurs worldwide and incurs considerable costs both from control measures and yield losses. Bacteria that cause CBC require one of six known type III transcription activator-like (TAL) effector genes for the characteristic pustule formation at the site of infection. Here, we show that Xanthomonas citri subspecies citri strain Xcc306, with the type III TAL effector gene pthA4 or with the distinct yet biologically equivalent gene pthAw from strain XccAw, induces two host genes, CsLOB1 and CsSWEET1, in a TAL effector-dependent manner. CsLOB1 is a member of the Lateral Organ Boundaries (LOB) gene family of transcription factors, and CsSWEET1 is a homolog of the SWEET sugar transporter and rice disease susceptibility gene. Both TAL effectors drive expression of CsLOB1 and CsSWEET1 promoter reporter gene fusions when coexpressed in citrus or Nicotiana benthamiana. Artificially designed TAL effectors directed to sequences in the CsLOB1 promoter region, but not the CsSWEET1 promoter, promoted pustule formation and higher bacterial leaf populations. Three additional distinct TAL effector genes, pthA*, pthB, and pthC, also direct pustule formation and expression of CsLOB1. Unlike pthA4 and pthAw, pthB and pthC do not promote the expression of CsSWEET1. CsLOB1 expression was associated with the expression of genes associated with cell expansion. The results indicate that CBC-inciting species of Xanthomonas exploit a single host disease susceptibility gene by altering the expression of an otherwise developmentally regulated gene using any one of a diverse set of TAL effector genes in the pathogen populations. PMID:24474801

  16. Lateral organ boundaries 1 is a disease susceptibility gene for citrus bacterial canker disease.

    PubMed

    Hu, Yang; Zhang, Junli; Jia, Hongge; Sosso, Davide; Li, Ting; Frommer, Wolf B; Yang, Bing; White, Frank F; Wang, Nian; Jones, Jeffrey B

    2014-01-28

    Citrus bacterial canker (CBC) disease occurs worldwide and incurs considerable costs both from control measures and yield losses. Bacteria that cause CBC require one of six known type III transcription activator-like (TAL) effector genes for the characteristic pustule formation at the site of infection. Here, we show that Xanthomonas citri subspecies citri strain Xcc306, with the type III TAL effector gene pthA4 or with the distinct yet biologically equivalent gene pthAw from strain XccA(w), induces two host genes, CsLOB1 and CsSWEET1, in a TAL effector-dependent manner. CsLOB1 is a member of the Lateral Organ Boundaries (LOB) gene family of transcription factors, and CsSWEET1 is a homolog of the SWEET sugar transporter and rice disease susceptibility gene. Both TAL effectors drive expression of CsLOB1 and CsSWEET1 promoter reporter gene fusions when coexpressed in citrus or Nicotiana benthamiana. Artificially designed TAL effectors directed to sequences in the CsLOB1 promoter region, but not the CsSWEET1 promoter, promoted pustule formation and higher bacterial leaf populations. Three additional distinct TAL effector genes, pthA*, pthB, and pthC, also direct pustule formation and expression of CsLOB1. Unlike pthA4 and pthAw, pthB and pthC do not promote the expression of CsSWEET1. CsLOB1 expression was associated with the expression of genes associated with cell expansion. The results indicate that CBC-inciting species of Xanthomonas exploit a single host disease susceptibility gene by altering the expression of an otherwise developmentally regulated gene using any one of a diverse set of TAL effector genes in the pathogen populations. PMID:24474801

  17. Characterization of five CYP4 genes from Asian citrus psyllid and their expression levels in Candidatus Liberibacter asiaticus-infected and uninfected psyllids.

    PubMed

    Tiwari, S; Gondhalekar, A D; Mann, R S; Scharf, M E; Stelinski, L L

    2011-12-01

    Previously, we reported that Candidatus Liberibacter asiaticus (Las)-infected Diaphorina citri are characterized by lower levels of cytochrome P450 monooxygenases than uninfected counterparts. In the present study, we investigated expression levels of family 4 cytochrome P450 (CYP4) genes in Las-infected and uninfected D.citri adults. Five novel CYP4 genes (CYP4C67, CYP4DA1, CYP4C68, CYP4DB1 and CYP4G70) were identified. Four of the five CYP4 genes were expressed at significantly higher levels in uninfected than Las-infected males, whereas only one was expressed at significantly higher levels in uninfected than Las-infected females. These results suggest that levels of cytochrome P450 monooxygenases in D.citri may be linked to expression levels of these CYP4 genes. Expression of all five CYP4 genes was induced by exposure of D.citri to imidacloprid, suggesting their possible involvement in metabolism of this toxin. Higher expression of the five CYP4 genes was found in nymphs than adults, which is congruent with previous results indicating higher levels of cytochrome P450 monooxygenases in nymphs than adults. These five CYP4 genes may be promising candidates for RNA-interference to silence overexpression of genes associated with insecticide resistance in D.citri. These newly identified genes may also serve as DNA-based screening markers for cytochrome P450-mediated insecticide resistance in field populations of D.citri. PMID:21919983

  18. Detection of a phytoplasma in citrus showing Huanglongbing (yellow shoot disease) symptoms in Guangdong, P. R. China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus Huanglongbing (HLB) or yellow shoot disease (ex. greening disease) is highly destructive to citrus production worldwide. Understanding the etiology of HLB is critical for managing the disease. HLB is currently known to be associated with infection by Candidatus Liberibacter asiaticus in China...

  19. MUTATION AT BETA-TUBULIN CODON 200 INDICATED THIABENDAZOLE RESISTANCE IN PENICILLIUM DIGITATUM COLLECTED FROM CALIFORNIA CITRUS PACKINGHOUSES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Penicillium digitatum, cause of citrus green mold, was isolated from infected lemons and oranges from many diverse locations in California. Those from groves, with no history of fungicide use, were sensitive to thiabendazole (TBZ), while those collected from ten citrus packinghouses were often TBZ r...

  20. Tylenchulus semipenetrans Alters the Microbial Community in the Citrus Rhizosphere1

    Microsoft Academic Search

    F. E. El-Borai; L. W. Duncan; J. H. Graham; E. Dickstein

    2003-01-01

    Infection of citrus seedlings by Tylenchulus semipenetrans was shown to reduce subsequent infection of roots by Phyto- phthora nicotianae and to increase plant growth compared to plants infected by only the fungus. Hypothetical mechanisms by which the nematode suppresses fungal development include nutrient competition, direct antibiosis, or alteration of the microbial com- munity in the rhizosphere to favor microorganisms antagonistic

  1. Overexpression of a citrus NDR1 ortholog increases disease resistance in Arabidopsis

    PubMed Central

    Lu, Hua; Zhang, Chong; Albrecht, Ute; Shimizu, Rena; Wang, Guanfeng; Bowman, Kim D.

    2013-01-01

    Emerging devastating diseases, such as Huanglongbing (HLB) and citrus canker, have caused tremendous losses to the citrus industry worldwide. Genetic engineering is a powerful approach that could allow us to increase citrus resistance against these diseases. The key to the success of this approach relies on a thorough understanding of defense mechanisms of citrus. Studies of Arabidopsis and other plants have provided a framework for us to better understand defense mechanisms of citrus. Salicylic acid (SA) is a key signaling molecule involved in basal defense and resistance (R) gene-mediated defense against broad-spectrum pathogens. The Arabidopsis gene NDR1 (NON-RACE-SPECIFIC DISEASE RESISTANCE 1) is a positive regulator of SA accumulation and is specifically required for signaling mediated by a subset of R genes upon recognition of their cognate pathogen effectors. Our bioinformatic analysis identified an ortholog of NDR1 from citrus, CsNDR1. Overexpression of CsNDR1 complemented susceptibility conferred by the Arabidopsis ndr1-1 mutant to Pseudomonas syringae strains and also led to enhanced resistance to an oomycete pathogen Hyaloperonospora arabidopsidis. Such heightened resistance is associated with increased SA production and expression of the defense marker gene PATHOGENESIS RELATED 1 (PR1). In addition, we found that expression of PR1 and accumulation of SA were induced to modest levels in citrus infected with Candidatus Liberibacter asiaticus, the bacterial pathogen associated with HLB disease. Thus, our data suggest that CsNDR1 is a functional ortholog of Arabidopsis NDR1. Since Ca. L. asiaticus infection only activates modest levels of defense responses in citrus, we propose that genetically increasing SA/NDR1-mediated pathways could potentially lead to enhanced resistance against HLB, citrus canker, and other destructive diseases challenging global citrus production. PMID:23761797

  2. A stable RNA virus-based vector for citrus trees

    SciTech Connect

    Folimonov, Alexey S.; Folimonova, Svetlana Y. [Department of Plant Pathology, University of Florida, Citrus Research and Education Center, 700 Experiment Station Road, Lake Alfred, FL 33850 (United States); Bar-Joseph, Moshe [The Volcani Center, Bet-Dagan 50259 (Israel); Dawson, William O. [Department of Plant Pathology, University of Florida, Citrus Research and Education Center, 700 Experiment Station Road, Lake Alfred, FL 33850 (United States)], E-mail: wodtmv@crec.ifas.ufl.edu

    2007-11-10

    Virus-based vectors are important tools in plant molecular biology and plant genomics. A number of vectors based on viruses that infect herbaceous plants are in use for expression or silencing of genes in plants as well as screening unknown sequences for function. Yet there is a need for useful virus-based vectors for woody plants, which demand much greater stability because of the longer time required for systemic infection and analysis. We examined several strategies to develop a Citrus tristeza virus (CTV)-based vector for transient expression of foreign genes in citrus trees using a green fluorescent protein (GFP) as a reporter. These strategies included substitution of the p13 open reading frame (ORF) by the ORF of GFP, construction of a self-processing fusion of GFP in-frame with the major coat protein (CP), or expression of the GFP ORF as an extra gene from a subgenomic (sg) mRNA controlled either by a duplicated CTV CP sgRNA controller element (CE) or an introduced heterologous CE of Beet yellows virus. Engineered vector constructs were examined for replication, encapsidation, GFP expression during multiple passages in protoplasts, and for their ability to infect, move, express GFP, and be maintained in citrus plants. The most successful vectors based on the 'add-a-gene' strategy have been unusually stable, continuing to produce GFP fluorescence after more than 4 years in citrus trees.

  3. Agreement: Citrus College Faculty Association and Citrus Community College District.

    ERIC Educational Resources Information Center

    Citrus Community Coll. District, Glendora, CA.

    The collective bargaining agreement between the Citrus Community College District Board of Trustees and the Citrus College Faculty/California Teachers Association/National Education Association is presented. This contract, covering the period from July 1988 through June 1990, deals with the following topics: bargaining agent recognition and…

  4. Antagonists of Plant-parasitic Nematodes in Florida Citrus

    PubMed Central

    Walter, David Evans; Kaplan, David T.

    1990-01-01

    In a survey of antagonists of nematodes in 27 citrus groves, each with a history of Tylenchulus semipenetrans infestation, and 17 noncitrus habitats in Florida, approximately 24 species of microbial antagonists capable of attacking vermiform stages of Radopholus citrophilus were recovered. Eleven of these microbes and a species of Pasteuria also were observed attacking vermiform stages of T. semipenetrans. Verticillium chlamydosporium, Paecilomyces lilacinus, P. marquandii, Streptomyces sp., Arthrobotrys oligospora, and Dactylella ellipsospora were found infecting T. semipenetrans egg masses. Two species of nematophagous amoebae, five species of predatory nematodes, and 29 species of nematophagous arthropods also were detected. Nematode-trapping fungi and nematophagous arthropods were common inhabitants of citrus groves with a history of citrus nematode infestation; however, obligate parasites of nematodes were rare. PMID:19287759

  5. Antifungal activity of lemon ( Citrus lemon L.), mandarin ( Citrus reticulata L.), grapefruit ( Citrus paradisi L.) and orange ( Citrus sinensis L.) essential oils

    Microsoft Academic Search

    M. Viuda-Martos; Y. Ruiz-Navajas; J. Fernández-López; J. Pérez-Álvarez

    2008-01-01

    The objective of this work was to study the effect of the essential oils of lemon (Citrus lemon L.), mandarin (Citrus reticulata L.), grapefruit (Citrus paradisi L.) and orange (Citrus sinensis L.) on the growth of moulds commonly associated with food spoilage: Aspergillus niger, Aspergillus flavus, Penicillium chrysogenum and Penicillium verrucosum, using the agar dilution method. All the oils showed

  6. Economic & Market Research Florida Citrus Outlook

    E-print Network

    Hill, Jeffrey E.

    Economic & Market Research Florida Citrus Outlook 2012-13 Season Florida Agricultural Commodity & Market Research Florida Department of Citrus #12;Economic & Market Research 2 Florida Citrus Outlook 2012-13 Season Available on-line at: http://www.fdocgrower.com/economics/economic- research/outlook-florida-citrus

  7. Potential nutritional benefits of current citrus consumption

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus contains various nutrients and phytochemicals that may be beneficial for health. We collected citrus production and consumption data and estimated the amount of these compounds that are currently consumed. We then compared the amount of citrus and citrus-derived compounds that have been use...

  8. CITRUS LIMONOID BIOAVAILABILITY IN HUMANS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The absorption, metabolism and bioavailability of citrus limonoids in human subjects administered high doses of pure limonin glucoside has been reported. In this chapter, the results from this study are compared to the bioavailability results of other citrus secondary metabolites, and future resear...

  9. Candidatus Liberibacter asiaticus titers in citrus cultivars in the field and in Asian Citrus Psyllid-inoculated greenhouse trees

    E-print Network

    McCollum, Greg; Hilf, Mark; Irey, Mike

    2014-01-01

    citrus cultivars (Citrus sinensis, C. paradisi, ‘Temple’sinensis, C. paradisi, Poncirus trifoliata, and nine citrussinensis. In the orchard, Candidatus Liberibacter asiaticus (CLas) is transmitted to citrus

  10. Candidate gene markers for Candidatus Liberibacter asiaticus for detecting citrus greening disease.

    PubMed

    Nageswara-Rao, Madhugiri; Irey, Mike; Garnsey, Stephen M; Gowda, Siddarame

    2013-06-01

    Citrus Huanglongbing (HLB) also known as citrus greening is one of the most devastating diseases of citrus worldwide. The disease is caused by Candidatus Liberibacter bacterium, vectored by the psyllid Diaphorina citri Kuwayama and Trioza erytreae Del Guercio. Citrus plants infected by the HLB bacterium may not show visible symptoms sometimes for years following infection. The aim of this study was to develop effective gene-specific primer pairs for polymerase chain reaction based method for quick screening of HLB disease. Thirty-two different gene-specific primer pairs, across the Ca. Liberibacter asiaticus genome, were successfully developed. The possibility of these primer pairs for cross-genome amplification across 'Ca. Liberibacter africanus' and 'Ca. Liberibacter americanus' were tested. The applicability of these primer pairs for detection and differentiation of Ca Liberibacter spp. is discussed. PMID:23660656

  11. Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae), vector of citrus huanglongbing disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is an important pest of citrus because it transmits phloem-limited bacteria [Candidatus Liberibacter spp., notably Ca. L. asiaticus (Las)], associated with huanglongbing (HLB; citrus greening), currently considered the...

  12. Resistance of Poncirus and Citrus x Poncirus germplam to the Asian citrus psyllid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, has spread to citrus growing regions nearly worldwide and adults transmit phloem-limited bacteria (Candidatus Liberibacter spp.) that are putatively responsible for citrus greening disease (huanglongbing). Host plant resistance ultimately ma...

  13. 75 FR 17289 - Citrus Seed Imports; Citrus Greening and Citrus Variegated Chlorosis

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-06

    ...greening is not known to exist in Costa Rica and Paraguay, but CVC is. Therefore...that seed of the genus Citrus from Costa Rica and Paraguay is prohibited importation...x) Seed of the genus Citrus from Costa Rica and Paraguay is prohibited...

  14. 78 FR 63369 - Citrus Canker, Citrus Greening, and Asian Citrus Psyllid; Interstate Movement of Regulated...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-24

    ...plant disease that is caused by a complex of Xanthomonas spp. bacteria and that affects plants and plant parts of citrus and citrus...the protocol document are adhered to, there should be no bacterium within the nursery or compartment. In that same section...

  15. Novel delivery of the fungi Paecilomyces formosoroseus (Deuteromycotina: Hyphomycetes) for managing the Asian citrus psyllid (Psyllidae: Hemiptera)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A method was developed to increase efficacy and reduce grower costs when using the biological control fungal agent Paecilomyces fumosoroseus blastospores (Deuteromycotina: Hyphomycetes) to infect adult Asian citrus psyllids, Diaphorina citri (Psyllidae: Hemiptera). We analyzed the efficacy of this ‘...

  16. Novel delivery of the fungi Paecilomyces formosoroseus (Deuteromycotina: Hyphomycetes) for managing the Asian citrus psyllid (Psyllidae: Hemiptera)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A method was developed to increase efficacy and reduce grower costs when using the biological control fungal agent Paecilomyces fumosoroseus blastospores (Deuteromycotina: Hyphomycetes) to infect adult Asian citrus psyllids, Diaphorina citri (Psyllidae: Hemiptera). We analyzed the efficacy of this A...

  17. High codon adaptation in citrus tristeza virus to its citrus host

    PubMed Central

    2012-01-01

    Background Citrus tristeza virus (CTV), a member of the genus Closterovirus within the family Closteroviridae, is the causal agent of citrus tristeza disease. Previous studies revealed that the negative selection, RNA recombination and gene flow were the most important forces that drove CTV evolution. However, the CTV codon usage was not studied and thus its role in CTV evolution remains unknown. Results A detailed comparative analysis of CTV codon usage pattern was done in this study. Results of the study show that although in general CTV does not have a high degree of codon usage bias, the codon usage of CTV has a high level of resemblance to its host codon usage. In addition, our data indicate that the codon usage resemblance is only observed for the woody plant-infecting closteroviruses but not the closteroviruses infecting the herbaceous host plants, suggesting the existence of different virus-host interactions between the herbaceous plant-infecting and woody plant-infecting closteroviruses. Conclusion Based on the results, we suggest that in addition to RNA recombination, negative selection and gene flow, host plant codon usage selection can also affect CTV evolution. PMID:22698086

  18. Infections

    MedlinePLUS

    ... Infections Warts West Nile Virus What Is "PANS"? Whooping Cough (Pertussis) Yersiniosis Ear Infections Can Chronic Ear Infections ... Scarlet Fever Sinusitis Strep Throat Tuberculosis Walking Pneumonia Whooping Cough (Pertussis) Medical Tests A Directory of Medical Tests ...

  19. New excised-leaf assay method to test inoculativity of Asian citrus psyllid (Hemiptera: Psyllidae) with Candidatus Liberibacter asiaticus associated with citrus huanglongbing disease.

    PubMed

    Ammar, El-Desouky; Walter, Abigail J; Hall, David G

    2013-02-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is the primary vector of Candidatus Liberibacter asiaticus (Las) associated with huanglongbing, or citrus greening, the most devastating citrus (Citrus spp.) disease worldwide. Here, we developed a new "excised-leaf assay" that can speed up Las-inoculativity tests on Asian citrus psyllid from the current 3-12 mo (when using whole citrus seedlings for inoculation) to only 2-3 wk. Young adults of Asian citrus psyllid that had been reared on Las-infected plants were caged on excised healthy sweet orange [Citrus sinensis (L.) Osbeck] leaves for a 1-2-wk inoculation access periods (IAP), and then both psyllids and leaves were tested later by quantitative polymerase chain reaction (PCR). When single adults were tested per leaf, percentages of Las-positive leaves averaged 2-6% by using HLBaspr primers and 10-20% by using the more sensitive LJ900 primers. Higher proportions of Las-positive leaves were obtained with 1) higher densities of inoculating psyllids (5-10 adults per leaf), 2) longer IAPs, and 3) incubation of leaves for 1 wk postinoculation before PCR. Logistic regression analysis indicated a positive correlation between Las titer in Asian citrus psyllid adults tested singly and the probability of detecting Las in the inoculated leaves, correlations that can be very useful in epidemiological studies. Comparison between excised leaves and whole seedlings, inoculated consecutively for 1 wk each by one or a group of psyllids, indicated no significant difference between Las detection in excised leaves or whole plants. This new excised-leaf assay method saves considerable time, materials, and greenhouse space, and it may enhance vector relation and epidemiological studies on Las and potentially other Liberibacter spp. associated with huanglongbing disease. PMID:23448011

  20. Citrus tristeza virus: a pathogen that changed the course of the citrus industry.

    PubMed

    Moreno, Pedro; Ambrós, Silvia; Albiach-Martí, Maria R; Guerri, José; Peña, Leandro

    2008-03-01

    Citrus tristeza virus (CTV) (genus Closterovirus, family Closteroviridae) is the causal agent of devastating epidemics that changed the course of the citrus industry. Adapted to replicate in phloem cells of a few species within the family Rutaceae and to transmission by a few aphid species, CTV and citrus probably coevolved for centuries at the site of origin of citrus plants. CTV dispersal to other regions and its interaction with new scion varieties and rootstock combinations resulted in three distinct syndromes named tristeza, stem pitting and seedling yellows. The first, inciting decline of varieties propagated on sour orange, has forced the rebuilding of many citrus industries using tristeza-tolerant rootstocks. The second, inducing stunting, stem pitting and low bearing of some varieties, causes economic losses in an increasing number of countries. The third is usually observed by biological indexing, but rarely in the field. CTV polar virions are composed of two capsid proteins and a single-stranded, positive-sense genomic RNA (gRNA) of approximately 20 kb, containing 12 open reading frames (ORFs) and two untranslated regions (UTRs). ORFs 1a and 1b, encoding proteins of the replicase complex, are directly translated from the gRNA, and together with the 5' and 3'UTRs are the only regions required for RNA replication. The remaining ORFs, expressed via 3'-coterminal subgenomic RNAs, encode proteins required for virion assembly and movement (p6, p65, p61, p27 and p25), asymmetrical accumulation of positive and negative strands during RNA replication (p23), or suppression of post-transcriptional gene silencing (p25, p20 and p23), with the role of proteins p33, p18 and p13 as yet unknown. Analysis of genetic variation in CTV isolates revealed (1) conservation of genomes in distant geographical regions, with a limited repertoire of genotypes, (2) uneven distribution of variation along the gRNA, (3) frequent recombination events and (4) different selection pressures shaping CTV populations. Measures to control CTV damage include quarantine and budwood certification programmes, elimination of infected trees, use of tristeza-tolerant rootstocks, or cross protection with mild isolates, depending on CTV incidence and on the virus strains and host varieties predominant in each region. Incorporating resistance genes into commercial varieties by conventional breeding is presently unfeasible, whereas incorporation of pathogen-derived resistance by plant transformation has yielded variable results, indicating that the CTV-citrus interaction may be more specific and complex than initially thought. A deep understanding of the interactions between viral proteins and host and vector factors will be necessary to develop reliable and sound control measures. PMID:18705856

  1. SCREENING CITRUS GERMPLASM FOR RESISTANCE TO XANTHOMONAS ANONOPODIS PV. CITRI

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus bacterial canker (causal agent Xanthomonas axonopodis pv. citri (Xac)) is a serious threat to the citrus industry. Currently there are no effective means to control citrus canker. Our objective was to determine the resistance of selected Citrus species, citrus hybrids, and citrus relatives to...

  2. Against the grain: safeguarding rice from rice blast disease.

    PubMed

    Skamnioti, Pari; Gurr, Sarah J

    2009-03-01

    Rice is the staple diet of more than three billion people. Yields must double over the next 40 years if we are to sustain the nutritional needs of the ever-expanding global population. Between 10% and 30% of the annual rice harvest is lost due to infection by the rice blast fungus Magnaporthe oryzae. Evaluation of genetic and virulence diversity of blast populations with diagnostic markers will aid disease management. We review the M. oryzae species-specific and cultivar-specific avirulence determinants and evaluate efforts towards generating durable and broad-spectrum resistance in single resistant cultivars or mixtures. We consider modern usage of fungicides and plant defence activators, assess the usefulness of biological control and categorize current approaches towards blast-tolerant genetically modified rice. PMID:19187990

  3. Research Associate: Rice Breeding Rice Experiment Station

    E-print Network

    Schladow, S. Geoffrey

    qualifications and experience. Requirements: Job qualifications include a degree in plant breeding, agronomyResearch Associate: Rice Breeding Rice Experiment Station California Cooperative Rice Research a position to work with the RES Rice Breeding Program in screening and evaluating tolerance of rice germplasm

  4. Citrus Canker: Alternatives for Control

    NSDL National Science Digital Library

    Linda Weinland (Edison College; Biology)

    2006-05-20

    What do you do when county officials show up to cut down the orange trees in your backyard? What causes citrus canker and how is it spread? This plant pathogen was the first microbe to have its genome sequenced outside of the US. There is much to investigate before deciding on the best alternative for control. * examine international alternatives for the control of citrus canker

  5. Principles of carbon catabolite repression in the rice blast fungus: Tps1, Nmr1-3, and a MATE-family pump regulate glucose metabolism during infection.

    PubMed

    Fernandez, Jessie; Wright, Janet D; Hartline, David; Quispe, Cristian F; Madayiputhiya, Nandakumar; Wilson, Richard A

    2012-01-01

    Understanding the genetic pathways that regulate how pathogenic fungi respond to their environment is paramount to developing effective mitigation strategies against disease. Carbon catabolite repression (CCR) is a global regulatory mechanism found in a wide range of microbial organisms that ensures the preferential utilization of glucose over less favourable carbon sources, but little is known about the components of CCR in filamentous fungi. Here we report three new mediators of CCR in the devastating rice blast fungus Magnaporthe oryzae: the sugar sensor Tps1, the Nmr1-3 inhibitor proteins, and the multidrug and toxin extrusion (MATE)-family pump, Mdt1. Using simple plate tests coupled with transcriptional analysis, we show that Tps1, in response to glucose-6-phosphate sensing, triggers CCR via the inactivation of Nmr1-3. In addition, by dissecting the CCR pathway using Agrobacterium tumefaciens-mediated mutagenesis, we also show that Mdt1 is an additional and previously unknown regulator of glucose metabolism. Mdt1 regulates glucose assimilation downstream of Tps1 and is necessary for nutrient utilization, sporulation, and pathogenicity. This is the first functional characterization of a MATE-family protein in filamentous fungi and the first description of a MATE protein in genetic regulation or plant pathogenicity. Perturbing CCR in ?tps1 and MDT1 disruption strains thus results in physiological defects that impact pathogenesis, possibly through the early expression of cell wall-degrading enzymes. Taken together, the importance of discovering three new regulators of carbon metabolism lies in understanding how M. oryzae and other pathogenic fungi respond to nutrient availability and control development during infection. PMID:22570632

  6. Different chitin synthase genes are required for various developmental and plant infection processes in the rice blast fungus Magnaporthe oryzae.

    PubMed

    Kong, Ling-An; Yang, Jun; Li, Guo-Tian; Qi, Lin-Lu; Zhang, Yu-Jun; Wang, Chen-Fang; Zhao, Wen-Sheng; Xu, Jin-Rong; Peng, You-Liang

    2012-02-01

    Chitin is a major component of fungal cell wall and is synthesized by chitin synthases (Chs). Plant pathogenic fungi normally have multiple chitin synthase genes. To determine their roles in development and pathogenesis, we functionally characterized all seven CHS genes in Magnaporthe oryzae. Three of them, CHS1, CHS6, and CHS7, were found to be important for plant infection. While the chs6 mutant was non-pathogenic, the chs1 and chs7 mutants were significantly reduced in virulence. CHS1 plays a specific role in conidiogenesis, an essential step for natural infection cycle. Most of chs1 conidia had no septum and spore tip mucilage. The chs6 mutant was reduced in hyphal growth and conidiation. It failed to penetrate and grow invasively in plant cells. The two MMD-containing chitin synthase genes, CHS5 and CHS6, have a similar expression pattern. Although deletion of CHS5 had no detectable phenotype, the chs5 chs6 double mutant had more severe defects than the chs6 mutant, indicating that they may have overlapping functions in maintaining polarized growth in vegetative and invasive hyphae. Unlike the other CHS genes, CHS7 has a unique function in appressorium formation. Although it was blocked in appressorium formation by germ tubes on artificial hydrophobic surfaces, the chs7 mutant still produced melanized appressoria by hyphal tips or on plant surfaces, indicating that chitin synthase genes have distinct impacts on appressorium formation by hyphal tip and germ tube. The chs7 mutant also was defective in appressorium penetration and invasive growth. Overall, our results indicate that individual CHS genes play diverse roles in hyphal growth, conidiogenesis, appressorium development, and pathogenesis in M. oryzae, and provided potential new leads in the control of this devastating pathogen by targeting specific chitin synthases. PMID:22346755

  7. Evaluation of the effects of light source and plant materials in psyllid trapping levels in the traps for citrus shipping containers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (ACP), the principle vector for Huanglongbing (HLB), has been reported to be transported in truckloads of oranges in Florida. Citrus, especially Key limes and lemons, are shipped to the U.S. from Mexican states that are heavily infested with HLB and live, infected psyllids c...

  8. Next generation sequencing of citrus affected by graft-transmissible diseases of unknown etiology leads to discovery of two novel viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus is susceptible to graft-transmissible pathogens; some of which are arthropod-transmitted. Citrus cultivars vary in susceptibility or tolerance to these pathogens and may remain symptomless when infected. Established tests for known disease agents are used in certification and disease manage...

  9. Colonization of citrus and citrus-related germplasm by Diaphorina citri (Hemiptera: Psyllidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is a serious and devastating disease of citrus caused by Candidatus Liberibacter spp. and vectored by the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae). The disease has the potential to greatly limit the production of citrus in Florida and other citrus gr...

  10. Citrus Grove Mapping

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Citrus growers have long used aerial photography to inventory the number of groves in production. A new development at Kennedy Space Center, aerial mapping of groves with color infrared (CIR) film, affords an important advance in grove management by detecting and locating unhealthy trees long before they could be detected by ground survey methods. Aerial CIR photography picks up light reflected from foliage-- light not visible to the human eye--and enables differentiation between healthy and "stressed" (diseased) trees of a Florida orange/grapefruit grove. Computer aided photo interpretation techniques permit grading diseased trees lightly, moderately or severely stressed or dead. Method of grove mapping has offered advantage to growers in early disease warning, possible savings through water regulation and provision of a permanent record of grove growth patterns.

  11. Citrus Canker and Citrus Huanglongbing, Two Exotic Bacterial Diseases Threatening the Citrus Industries of the Western Hemisphere

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two exotic Asian bacterial diseases of citrus are currently plaguing citrus industries in the Western Hemisphere. The two largest citrus producing areas in the Americas, located in Florida and the state of São Paulo Brazil, are presently battling these devastating diseases. The presence of these d...

  12. CITRUS CANKER: PLANT PATHOLOGY VERSUS PUBLIC POLICY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increasing international travel and trade has resulted in an unprecedented number of plant pathogen introductions, including Xanthomonas axonopodis pv citri, (Xac), the bacterium that causes citrus canker. The disease affects commercial and dooryard citrus, and has far-reaching politi...

  13. Control of virus diseases of citrus.

    PubMed

    Lee, Richard F

    2015-01-01

    Citrus is thought to have originated in Southeast Asia and horticulturally desirable clonal selections have been clonally cultivated for hundreds of years. While some citrus species have nucellar embryony, most cultivation of citrus has been by clonal propagation to ensure that propagated plants have the same traits as the parent selection. Clonal propagation also avoids juvenility, and the propagated plants produce fruit sooner. Because of the clonal propagation of citrus, citrus has accumulated a large number of viruses; many of these viruses are asymptomatic until a susceptible rootstock and/or scion is encountered. The viruses reported to occur in citrus will be summarized in this review. Methods of therapy to clean selected clones from viruses will be reviewed; the use of quarantine, clean stock, and certification programs for control of citrus viruses and other strategies to control insect spread citrus viruses, such as mild strain cross-protection and the use of pest management areas will be discussed. PMID:25591879

  14. Rice SAPs are responsive to multiple biotic stresses and overexpression of OsSAP1, an A20/AN1 zinc-finger protein, enhances the basal resistance against pathogen infection in tobacco.

    PubMed

    Tyagi, Himani; Jha, Shweta; Sharma, Meenakshi; Giri, Jitender; Tyagi, Akhilesh K

    2014-08-01

    Eukaryotic A20/AN1 zinc-finger proteins (ZFPs) play an important role in the regulation of immune and stress response. After elucidation of the role of first such protein, OsSAP1, in abiotic stress tolerance, 18 rice stress associated protein (SAP) genes have been shown to be regulated by multiple abiotic stresses. In the present study, expression pattern of all the 18 OsSAP genes have been analysed in response to different biotic stress simulators, in order to get insights into their possible involvement in biotic stress tolerance. Our results showed the upregulation of OsSAP1 and OsSAP11 by all biotic stress simulator treatments. Furthermore, the functional role of OsSAP1 in plant defence responses has been explored through overexpression in transgenic plants. Constitutive expression of OsSAP1 in transgenic tobacco resulted into enhanced disease resistance against virulent bacterial pathogen, together with the upregulation of known defence-related genes. Present investigation suggests that rice SAPs are responsive to multiple biotic stresses and OsSAP1 plays a key role in basal resistance against pathogen infection. This strongly supports the involvement of rice SAPs in cross-talk between biotic and abiotic stress signalling pathways, which makes them ideal candidate to design strategies for protecting crop plants against multiple stresses. PMID:25017161

  15. Genetically Engineered Rice Resistant to Rice Stripe Virus, an Insect Transmitted Virus

    Microsoft Academic Search

    Takahiko Hayakawa; Yafeng Zhu; Kimiko Itoh; Yusuke Kimura; Takeshi Izawa; Ko Shimamoto; Shigemitsu Toriyama

    1992-01-01

    The coat protein (CP) gene of rice stripe virus was introduced into two japonica varieties of rice by electroporation of protoplasts. The resultant transgenic plants expressed the CP at high levels (up to 0.5% of total soluble protein) and exhibited a significant level of resistance to virus infection. Plants derived from selfed progeny of the primary transformants also expressed the

  16. Citrus tristeza virus-aphid interactions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A review chapter on aphid transmission of Citrus tristeza virus is provided for a book on “Vector-Mediated Transmission of Plant Pathogens”. Earliest uses of citrus goes back over two millennia as items of trade, gifts and medicinal compounds. Citrus propagation during this period was by seed and si...

  17. Citrus Limonoids: Analysis, Bioactivity, and Biomedical Prospects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This publication is a review of the chemistry, biochemistry and bioactivity of limonoids occurring in citrus. The review chronologically relates the evolution of research in citrus limonoids beginning with their association with bitterness development in citrus juices. The chemical and biochemical...

  18. Bylaws of the Citrus Research & Education Center

    E-print Network

    Jawitz, James W.

    Bylaws of the Citrus Research & Education Center University of Florida December 12th , 2012 Preamble The shared goals of the faculty and administration of the Citrus Research & Education Center are to discover and deliver innovative solutions that empower citrus and other agricultural interests to conduct

  19. Citrus College Portland State University Transfer Worksheet

    E-print Network

    Caughman, John

    Citrus College Portland State University Transfer Worksheet If you are taking classes that are part of the Intersegmental General Education Transfer Curriculum (IGETC) at Citrus College (CC), you can rest assured. General Education Requirements #12;Citrus College Portland State University 2. DEGREE REQUIREMENTS

  20. RESEARCH ARTICLE Insecticidal Suppression of Asian Citrus

    E-print Network

    Florida, University of

    RESEARCH ARTICLE Insecticidal Suppression of Asian Citrus Psyllid Diaphorina citri (Hemiptera@ufl.edu Abstract Diaphorina citri vectors pathogens that cause `huanglongbing' or citrus greening disease which poses a serious threat to citrus production worldwide. Vector suppression is critical to reduce disease

  1. Citrus tristeza virus-host interactions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus tristeza virus (CTV) is a phloem-limited virus whose natural host range is restricted to citrus and related species. Although the virus has killed millions of trees, almost destroying whole industries, and continually limits production in many citrus growing areas, most isolates are mild or s...

  2. Rice University | Rice Facts Index Undergraduates Graduates Faculty & Researchers Staff Alumni

    E-print Network

    Richards-Kortum, Rebecca

    Rice University | Rice Facts Index Undergraduates Graduates Faculty & Researchers Staff Alumni Rice Facts Rice Facts Index Rice Culture Academics Campus Features Rice Administration Resources Historical Facts Archives About OIR Rice News Feed Font Size Rice Facts Rice Culture Mission History

  3. Citrus Tissue Culture

    PubMed Central

    Einset, John W.

    1978-01-01

    In vitro growth of explant (juice vesicle or albedo tissues) cultures from citron (Citrus medica), lemon (C. limon), grapefruit (C. paradisi), sweet orange (C. sinensis), and mandarin (C. reticulata) fruits was stimulated by addition of orange juice (10% v/v optimum) to a basal medium containing Murashige and Skoog salts, 50 grams per liter sucrose, 100 milligrams per liter myo-inositol, 5 milligrams per liter thiamine·HCl, 2 milligrams per liter 2,4-dichlorophenoxyacetic acid and 0.5 milligrams per liter kinetin. In analyzing this effect of orange juice on citron explant cultures, we failed to obtain increased yields by addition of appropriate concentrations of citric acid to the basal medium but obtained growth stimulation when the medium was supplemented with juice from an “acidless” orange variety (cv. Lima). These facts suggest that some component(s) other than citric acid is involved. Addition of the inorganic ash corresponding to 10% (v/v) orange juice to the basal medium had no effect on yields. Similarly, the stimulatory effect of orange juice could not be explained based on its content of sucrose or of organic growth factors already present in the basal medium. ImagesFig. 2 PMID:16660631

  4. Florida Citrus Industry Oral Histories

    NSDL National Science Digital Library

    What's so special about oranges? They are a major cash crop for Florida and other warm weather places, and this fascinating oral history project from the University of South Florida (USF) explores the very nature of this industry. Working together with the USF's Patel Center for Global Studies, oral historian William Mansfield conducted 20 interviews regarding the impact of globalization on the Florida citrus industry. Visitors can listen to or read the interviews, as well as look over the online exhibition, "Selling Sunshine: Florida's Citrus Industry." The exhibition details Florida's unique relationship with the citrus industry, incorporating documents, promotional material, and post cards with its information. The website hosts a remarkable collection that will be of interest to oral historians, folks with an interest in Florida, and many others.

  5. Bud emergence and shoot growth from mature citrus nodal segments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bud emergence and shoot growth from adult phase citrus nodal cultures were studied using Citrus mitis (calamondin), Citrus paradisi (grapefruit), and Citrus sinensis (sweet orange). The effects of 6-benzylaminopurine (BA), indole 3-acetic acid (IAA), and citrus type on shoot quality and growth fro...

  6. Genome-Wide Analysis of Citrus R2R3MYB Genes and Their Spatiotemporal Expression under Stresses and Hormone Treatments

    PubMed Central

    He, Shaolan; Zheng, Yongqiang; Yi, Shilai; Lv, Qiang; Deng, Lie

    2014-01-01

    The R2R3MYB proteins represent one of the largest families of transcription factors, which play important roles in plant growth and development. Although genome-wide analysis of this family has been conducted in many species, little is known about R2R3MYB genes in citrus, In this study, 101 R2R3MYB genes has been identified in the citrus (Citrus sinesis and Citrus clementina) genomes, which are almost equal to the number of rice. Phylogenetic analysis revealed that they could be subdivided into 21 subgroups. The evolutionary relationships and the intro-exon organizations were also analyzed, revealing strong gene conservation but also the expansions of particular functional genes during the plant evolution. Tissue-specific expression profiles showed that 95 citrus R2R3MYB genes were expressed in at least one tissue and the other 6 genes showed very low expression in all tissues tested, suggesting that citrus R2R3MYB genes play important roles in the development of all citrus organs. The transcript abundance level analysis during abiotic conditions (NaCl, abscisic acid, jasmonic acid, drought and low temperature) identified a group of R2R3MYB genes that responded to one or multiple treatments, which showed a promising for improving citrus adaptation to stresses. Our results provided an essential foundation for the future selection of the citrus R2R3MYB genes for cloning and functional dissection with an aim of uncovering their roles in citrus growth and development. PMID:25473954

  7. PRODUCTION OF INDIAN CITRUS RINGSPOT VIRUS FREE PLANTS OF KINNOW EMPLOYING CHEMOTHERAPY COUPLED WITH SHOOT TIP GRAFTING

    Microsoft Academic Search

    SANJEEV Sharma; BALWINDER Singh; AVINASH Nagpal

    2007-01-01

    Indian citrus ringspot virus (ICRSV) is known to cause serious problem in Kinnow (Citrus nobilis Lour × C. deliciosa Tenora). This paper reports the elimination of ICRSV from Kinnow by chemotherapy coupled with shoot tip grafting under in vitro conditions. Nodal segments from infected mother plant (indexed by indirect ELISA and RT-PCR) were cultured on MS medium containing 2-iP (1mg\\/l)

  8. Texas Rice, Highlights in Research

    E-print Network

    2007-01-01

    rice lines, disease lesions quickly extend all the way up to the flag leaf and even affect the panicle, causing severe yield losses. In tolerant rice varieties such as Jasmine 85 or TeQing, R. solani is still seen to infect the sheaths, but disease... tolerant lines such as Jasmine 85 and TeQing, and susceptible lines like Lemont, but also the moderate levels of tolerance exhibited by Saber and Maybelle were detect- able with the new seedling evaluation method. Plant-to-plant vari- ability...

  9. Rice Varieties.

    E-print Network

    Hodges, R. J.; Bollich, C. N.; Marchetti, M. A.; Webb, B. D.

    1979-01-01

    in Louisiana where blast is a problem. Brazos. This variety was developed from the cross C.I. 9545 x Nova and released by the Agricultural Research and Extension Center at Beaumont in 1974. The spikelet of Brazos is straw-colored, smooth and awnless... and is similar to Vista in this respect. Brazos' milling, cooking, eating and processing qualities are typical of traditional U.S. medium-grain rice. Its milling quality in terms of whole-grain and total milled rice is similar to Nova 76 and generally below...

  10. Exogenous treatment with salicylic acid attenuates occurrence of citrus canker in susceptible navel orange (Citrus sinensis Osbeck).

    PubMed

    Wang, Yin; Liu, Ji-Hong

    2012-08-15

    Citrus canker caused by Xanthomonas axonopodis pv. citri (Xac) is a devastating bacterial disease threatening the citrus industry. Salicylic acid (SA) plays a key role in plant defense response to biotic stress, but information is scarce concerning the application of SA to enhancing Xac resistance. In the present research attempts were made to investigate how exogenous application of SA influenced canker disease outbreak in navel orange (Citrus sinensis). Exogenously applied SA at 0.25 mM significantly enhanced the endogenous free and bound SA, particularly the latter. Upon exposure to Xac, lower disease incidence rate and smaller lesion sites were observed in the samples pre-treated with SA, accompanied by repression of bacterial growth at the lesion sites. Concurrent with the augmented disease resistance, SA-treated leaves had higher H?O? level and smaller stomata apertures before or after Xac infection when compared with their counterparts pre-treated with water (control). SA treatment elevated the activities of phenylalanine ammonia-lyase and ?-1,3-glucanase, but only the latter was higher in the SA-treated samples after Xac infection. In addition, mRNA levels of two pathogenesis-related genes, CsCHI and CsPR4A, were higher in the SA-treated samples relative to the control. Taken together, our results strongly suggest that the exogenously applied SA has evoked a cascade of physiological and molecular events that function singly or in concert to confer resistance to Xac invasion. PMID:22658220

  11. Huanglongbing, a Systemic Disease, Restructures the Bacterial Community Associated with Citrus Roots?

    PubMed Central

    Trivedi, Pankaj; Duan, Yongping; Wang, Nian

    2010-01-01

    To examine the effect of pathogens on the diversity and structure of plant-associated bacterial communities, we carried out a molecular analysis using citrus and huanglongbing as a host-disease model. 16S rRNA gene clone library analysis of citrus roots revealed shifts in microbial diversity in response to pathogen infection. The clone library of the uninfected root samples has a majority of phylotypes showing similarity to well-known plant growth-promoting bacteria, including Caulobacter, Burkholderia, Lysobacter, Pantoea, Pseudomonas, Stenotrophomonas, Bacillus, and Paenibacillus. Infection by “Candidatus Liberibacter asiaticus” restructured the native microbial community associated with citrus roots and led to the loss of detection of most phylotypes while promoting the growth of bacteria such as Methylobacterium and Sphingobacterium. In pairwise comparisons, the clone library from uninfected roots contained significantly higher 16S rRNA gene diversity, as reflected in the higher Chao 1 richness estimation (P ? 0.01) of 237.13 versus 42.14 for the uninfected and infected clone libraries, respectively. Similarly, the Shannon index of the uninfected clone library (4.46) was significantly higher than that of the infected clone library (2.61). Comparison of the uninfected clone library with the infected clone library using LIBSHUFF statistics showed a significant difference (P ? 0.05). Quantitative PCR analysis revealed that the bacterial community changes not only qualitatively but also quantitatively. The relative proportions of different groups of bacteria changed significantly after infection with the pathogen. These data indicate that infection of citrus by “Ca. Liberibacter asiaticus” has a profound effect on the structure and composition of the bacterial community associated with citrus roots. PMID:20382817

  12. Effects of soil-applied imidacloprid on Asian citrus psyllid (Hemiptera: Psyllidae) feeding behavior.

    PubMed

    Serikawa, R H; Backus, E A; Rogers, M E

    2012-10-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is one of the most important pests of citrus (Citrus spp.) because of its status as a vector of Candidatus Liberibacter asiaticus (Las), the bacterium associated with citrus greening disease. The use of insecticides for vector control is the primary method of managing the spread of this pathogen. Imidacloprid is an insecticide commonly applied to the root zone of young citrus trees to provide systemic protection from pests. The effects of imidacloprid on feeding behavior of D. citri have not been studied in much detail. The purpose of this study was to examine the effects of imidacloprid application on feeding behavior of D. citri and to determine whether use of this systemic insecticide could have any effect on pathogen transmission by D. citri. A direct current electrical penetration graph monitor was used to record D. citri feeding behaviors for 12-h periods on mature and young leaves of imidacloprid-treated and -untreated citrus seedlings. Overall, compared with untreated plants, the feeding behavior of D. citri was disrupted on imidacloprid-treated plants via reduction in the number of probes, as well as durations of average probes, initial stylet contact with phloem, phloem salivation, and phloem ingestion. The results of this study demonstrate that soil applications of imidacloprid can reduce the probability of citrus plants becoming inoculated with Las through a reduction in the number and duration of phloem salivation events by D. citri. Furthermore, Las acquisition from infected citrus is greatly reduced as a result of decreased phloem ingestion by D. citri on imidacloprid-treated plants. PMID:23156142

  13. Symptoms induced by transgenic expression of p23 from Citrus tristeza virus in phloem-associated cells of Mexican lime mimic virus infection without the aberrations accompanying constitutive expression.

    PubMed

    Soler, Nuria; Fagoaga, Carmen; López, Carmelo; Moreno, Pedro; Navarro, Luis; Flores, Ricardo; Peña, Leandro

    2015-05-01

    Citrus tristeza virus (CTV) is phloem restricted in natural citrus hosts. The 23-kDa protein (p23) encoded by the virus is an RNA silencing suppressor and a pathogenicity determinant. The expression of p23, or its N-terminal 157-amino-acid fragment comprising the zinc finger and flanking basic motifs, driven by the constitutive 35S promoter of cauliflower mosaic virus, induces CTV-like symptoms and other aberrations in transgenic citrus. To better define the role of p23 in CTV pathogenesis, we compared the phenotypes of Mexican lime transformed with p23-derived transgenes from the severe T36 and mild T317 CTV isolates under the control of the phloem-specific promoter from Commelina yellow mottle virus (CoYMV) or the 35S promoter. Expression of the constructs restricted to the phloem induced a phenotype resembling CTV-specific symptoms (vein clearing and necrosis, and stem pitting), but not the non-specific aberrations (such as mature leaf epinasty and yellow pinpoints, growth cessation and apical necrosis) observed when p23 was ectopically expressed. Furthermore, vein necrosis and stem pitting in Mexican lime appeared to be specifically associated with p23 from T36. Phloem-specific accumulation of the p23?158-209(T36) fragment was sufficient to induce the same anomalies, indicating that the region comprising the N-terminal 157 amino acids of p23 is responsible (at least in part) for the vein clearing, stem pitting and, possibly, vein corking in this host. PMID:25171669

  14. Materials for Controlling Asian Citrus Psyllid (Carrier of Citrus Greening) in Home Landscapes, Gardens, & Non-Commercial Orchards

    E-print Network

    Mukhtar, Saqib

    Materials for Controlling Asian Citrus Psyllid (Carrier of Citrus Greening) in Home Landscapes, Gardens, & Non-Commercial Orchards Asian Citrus Psyllid may infest a citrus tree throughout the year of the products listed below. Citrus growers should therefore monitor their trees regularly for the presence

  15. Structural and biochemical characteristics of citrus flowers associated with defence against a fungal pathogen.

    PubMed

    Marques, João Paulo Rodrigues; Amorim, Lilian; Silva-Junior, Geraldo José; Spósito, Marcel Bellato; Appezzato-da Gloria, Beatriz

    2014-01-01

    The constitutive characters of plants can be structural or biochemical and play an important role in their defence against pathogens. Citrus postbloom fruit drop (PFD) caused by Colletotrichum spp. is one of the most important fungal diseases of citrus. The pathogen infects the flowers, leading to premature fruit drop and reducing citrus production. However, flower buds smaller than 8 mm long are usually not infected by Colletotrichum spp. Thus, this study investigated whether there are constitutive mechanisms in flower buds related to Colletotrichum spp. infection. We studied flower buds that were 2, 3, 4, 8, 12 and 15 mm long and petals, after anthesis, of sweet orange 'Valência' using light and scanning electron microscopy and histochemistry. We evaluated the effect of volatile organic compounds (VOCs) in flowers (R-limonene and linalool) on the in vitro growth of Colletotrichum acutatum. We found that the arrangement of the epidermal papillae in the petal primordia, the occurrence of prismatic crystals and the distribution of oil glands are the main differences between buds smaller than 8 mm and buds 8-15 mm long. Osmophores at the tips of petals produced and accumulated phenols, terpenes and lipophilic compounds. Flower buds smaller than 8 mm long have constitutive structural and biochemical barriers to Colletotrichum spp. infection. In addition, this is the first time that osmophores have been reported in citrus. Our study shows that natural terpenes of Citrus flowers inhibit the fungal growth in vitro, highlighting the potential use of terpenes for the chemical control of PFD in citrus. PMID:25535209

  16. Stylet morphometrics and citrus leaf vein structure in relation to feeding behavior of the Asian citrus psyllid Diaphorina citri, vector of citrus huanglongbing bacterium.

    PubMed

    Ammar, El-Desouky; Hall, David G; Shatters, Robert G

    2013-01-01

    The Asian citrus psyllid (ACP), Diaphorina citri (Hemiptera: Psyllidae), is the primary vector of the phloem-limited bacterium Candidatus Liberibacter asiaticus (LAS) associated with huanglongbing (HLB, citrus greening), considered the world's most serious disease of citrus. Stylet morphometrics of ACP nymphs and adults were studied in relation to citrus vein structure and to their putative (histologically verified) feeding sites on Valencia orange leaves. ACP nymphs preferred to settle and feed on the lower (abaxial) side of young leaves either on secondary veins or on the sides of the midrib, whereas adults preferred to settle and feed on the upper (adaxial) or lower secondary veins of young or old leaves. Early instar nymphs can reach and probe the phloem probably because the distance to the phloem is considerably shorter in younger than in mature leaves, and is shorter from the sides of the midrib compared to that from the center. Additionally, the thick-walled 'fibrous ring' (sclerenchyma) around the phloem, which may act as a barrier to ACP stylet penetration into the phloem, is more prominent in older than in younger leaves and in the center than on the sides of the midrib. The majority (80-90%) of the salivary sheath termini produced by ACP nymphs and adults that reached a vascular bundle were associated with the phloem, whereas only 10-20% were associated with xylem vessels. Ultrastructural studies on ACP stylets and LAS-infected leaves suggested that the width of the maxillary food canal in first instar nymphs is wide enough for LAS bacteria to traverse during food ingestion (and LAS acquisition). However, the width of the maxillary salivary canal in these nymphs may not be wide enough to accommodate LAS bacteria during salivation (and LAS inoculation) into host plants. This may explain the inability of early instar nymphs to transmit LAS/HLB in earlier reports. PMID:23555830

  17. Stylet Morphometrics and Citrus Leaf Vein Structure in Relation to Feeding Behavior of the Asian Citrus Psyllid Diaphorina citri, Vector of Citrus Huanglongbing Bacterium

    PubMed Central

    Ammar, El-Desouky; Hall, David G.; Shatters, Robert G.

    2013-01-01

    The Asian citrus psyllid (ACP), Diaphorina citri (Hemiptera: Psyllidae), is the primary vector of the phloem-limited bacterium Candidatus Liberibacter asiaticus (LAS) associated with huanglongbing (HLB, citrus greening), considered the world’s most serious disease of citrus. Stylet morphometrics of ACP nymphs and adults were studied in relation to citrus vein structure and to their putative (histologically verified) feeding sites on Valencia orange leaves. ACP nymphs preferred to settle and feed on the lower (abaxial) side of young leaves either on secondary veins or on the sides of the midrib, whereas adults preferred to settle and feed on the upper (adaxial) or lower secondary veins of young or old leaves. Early instar nymphs can reach and probe the phloem probably because the distance to the phloem is considerably shorter in younger than in mature leaves, and is shorter from the sides of the midrib compared to that from the center. Additionally, the thick-walled ‘fibrous ring’ (sclerenchyma) around the phloem, which may act as a barrier to ACP stylet penetration into the phloem, is more prominent in older than in younger leaves and in the center than on the sides of the midrib. The majority (80–90%) of the salivary sheath termini produced by ACP nymphs and adults that reached a vascular bundle were associated with the phloem, whereas only 10–20% were associated with xylem vessels. Ultrastructural studies on ACP stylets and LAS-infected leaves suggested that the width of the maxillary food canal in first instar nymphs is wide enough for LAS bacteria to traverse during food ingestion (and LAS acquisition). However, the width of the maxillary salivary canal in these nymphs may not be wide enough to accommodate LAS bacteria during salivation (and LAS inoculation) into host plants. This may explain the inability of early instar nymphs to transmit LAS/HLB in earlier reports. PMID:23555830

  18. Development of rapid, sensitive and non-radioactive tissue-blot diagnostic method for the detection of citrus greening.

    PubMed

    Nageswara-Rao, Madhugiri; Miyata, Shin-Ichi; Ghosh, Dilip; Irey, Mike; Garnsey, Stephen M; Gowda, Siddarame

    2013-01-01

    Citrus huanglongbing (HLB or citrus greening) is one of the most devastating diseases of citrus worldwide. The disease is caused by Gram-negative, phloem-limited ?-proteobacterium, 'Candidatus Liberibacter asiaticus', vectored by the psyllid, Diaphorina citri Kuwayama. Citrus plants infected by the HLB bacterium may not show visible symptoms sometimes for years following infection and non-uniform distribution within the tree makes the detection of the pathogen very difficult. Efficient management of HLB disease requires rapid and sensitive detection early in the infection followed by eradication of the source of pathogen and the vector. The polymerase chain reaction (PCR) based method is most commonly employed for screening the infected/suspected HLB plants and psyllids. This is time consuming, cumbersome and not practical for screening large number of samples in the field. To overcome this, we developed a simple, sensitive, non-radioactive, tissue-blot diagnostic method for early detection and screening of HLB disease. Digoxigenin labeled molecular probes specific to 'Ca. L. asiaticus' nucleotide sequences have been developed and used for the detection of the pathogen of the HLB disease. The copy number of the target genes was also assessed using real-time PCR experiments and the optimized real-time PCR protocol allowed positive 'Ca. L. asiaticus' detection in citrus samples infected with 'Ca. L. asiaticus' bacterium. PMID:23660459

  19. Chipping citrus wood for gasification

    SciTech Connect

    Churchill, D.B.; Hedden, S.L.; Whitney, J.D.; Shaw, L.N.

    1985-01-01

    Non-productive citrus trees were chipped with a portable fly-wheel-type chipper powered by a 45 kW engine. Chips were air dried under an open shed to 14% (w.b.) moisture content. By weight, approximately 50% of the total tree could be made into usable chips. The root system averaged 36% of the total tree weight.

  20. 7 CFR 319.56-41 - Citrus from Peru.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...and Vegetables § 319.56-41 Citrus from Peru. Grapefruit (Citrus paradisi ), limes (C. aurantiifolia ), mandarins or tangerines (C. reticulata ), sweet oranges (C. sinensis ), and tangelos (Citrus tangelo ) may be...

  1. 7 CFR 319.56-41 - Citrus from Peru.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...and Vegetables § 319.56-41 Citrus from Peru. Grapefruit (Citrus paradisi ), limes (C. aurantiifolia ), mandarins or tangerines (C. reticulata ), sweet oranges (C. sinensis ), and tangelos (Citrus tangelo ) may be...

  2. 7 CFR 319.56-41 - Citrus from Peru.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...and Vegetables § 319.56-41 Citrus from Peru. Grapefruit (Citrus paradisi ), limes (C. aurantiifolia ), mandarins or tangerines (C. reticulata ), sweet oranges (C. sinensis ), and tangelos (Citrus tangelo ) may be...

  3. 7 CFR 319.56-41 - Citrus from Peru.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...and Vegetables § 319.56-41 Citrus from Peru. Grapefruit (Citrus paradisi ), limes (C. aurantiifolia ), mandarins or tangerines (C. reticulata ), sweet oranges (C. sinensis ), and tangelos (Citrus tangelo ) may be...

  4. 7 CFR 319.56-41 - Citrus from Peru.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...and Vegetables § 319.56-41 Citrus from Peru. Grapefruit (Citrus paradisi ), limes (C. aurantiifolia ), mandarins or tangerines (C. reticulata ), sweet oranges (C. sinensis ), and tangelos (Citrus tangelo ) may be...

  5. Site Plan & Site Section of Citrus Landscape (Showing Relationship ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Site Plan & Site Section of Citrus Landscape (Showing Relationship of Victoria Avenue to Citrus Groves) - Arlington Heights Citrus Landscape, Southwestern portion of city of Riverside, Riverside, Riverside County, CA

  6. 7 CFR 905.31 - Duties of Citrus Administrative Committee.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Duties of Citrus Administrative Committee. 905.31...Administrative Bodies § 905.31 Duties of Citrus Administrative Committee. It shall be the duty of the Citrus Administrative Committee:...

  7. 7 CFR 905.31 - Duties of Citrus Administrative Committee.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Duties of Citrus Administrative Committee. 905.31...Administrative Bodies § 905.31 Duties of Citrus Administrative Committee. It shall be the duty of the Citrus Administrative Committee:...

  8. 7 CFR 905.31 - Duties of Citrus Administrative Committee.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Duties of Citrus Administrative Committee. 905.31...Administrative Bodies § 905.31 Duties of Citrus Administrative Committee. It shall be the duty of the Citrus Administrative Committee:...

  9. 1-Methylcyclopropene Applications in Preharvest Systems: Focus on Citrus

    E-print Network

    Burns, Jacqueline K.

    1-Methylcyclopropene Applications in Preharvest Systems: Focus on Citrus Jacqueline K. Burns1 University of Florida, IFAS, Horticultural Sciences Department, Citrus Research and Education Center, 700-MCP to prevent unwanted defoliation using ethephon to loosen mature citrus fruit is presented

  10. 7 CFR 905.31 - Duties of Citrus Administrative Committee.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Duties of Citrus Administrative Committee. 905.31...Administrative Bodies § 905.31 Duties of Citrus Administrative Committee. It shall be the duty of the Citrus Administrative Committee:...

  11. 7 CFR 905.31 - Duties of Citrus Administrative Committee.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 2011-01-01 false Duties of Citrus Administrative Committee. 905.31...Administrative Bodies § 905.31 Duties of Citrus Administrative Committee. It shall be the duty of the Citrus Administrative Committee:...

  12. Entomopathogenic fungus, Isaria fumosorosea, and aphid parasitoid, Lysiphlebus testaceipes, for managing infestations of Brown citrus aphid, Toxoptera citricida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An insect-infecting fungal pathogen, (Isaria fumosorosea [Ifr])sold as the product PFR 97™ was shown to be effective at killing aphid pests while not decreasing beneficial parasitoids. The brown citrus aphid, Toxoptera citricida (Kirkaldy)(Hemiptera: Aphididae) spreads the plant-infecting virus, Cit...

  13. Novel diagnosis for citrus stubborn disease by detection of a spiroplasma citri-secreted protein.

    PubMed

    Shi, Jinxia; Pagliaccia, Deborah; Morgan, Robyn; Qiao, Yongli; Pan, Songqin; Vidalakis, Georgios; Ma, Wenbo

    2014-02-01

    Citrus stubborn disease (CSD), first identified in California, is a widespread bacterial disease found in most arid citrus-producing regions in the United States and the Mediterranean Region. The disease is caused by Spiroplasma citri, an insect-transmitted and phloem-colonizing bacterium. CSD causes significant tree damage resulting in loss of fruit production and quality. Detection of CSD is challenging due to low and fluctuating titer and sporadic distribution of the pathogen in infected trees. In this study, we report the development of a novel diagnostic method for CSD using an S. citri-secreted protein as the detection marker. Microbial pathogens secrete a variety of proteins during infection that can potentially disperse systemically in infected plants with the vascular flow. Therefore, their distribution may not be restricted to the pathogen infection sites and could be used as a biological marker for infection. Using mass spectrometry analysis, we identified a unique secreted protein from S. citri that is highly expressed in the presence of citrus phloem extract. ScCCPP1, an antibody generated against this protein, was able to distinguish S. citri-infected citrus and periwinkle from healthy plants. In addition, the antiserum could be used to detect CSD using a simple direct tissue print assay without the need for sample processing or specialized lab equipment and may be suitable for field surveys. This study provides proof of a novel concept of using pathogen-secreted protein as a marker for diagnosis of a citrus bacterial disease and can probably be applied to other plant diseases. PMID:23931112

  14. Huanglongbing alters the structure and functional diversity of microbial communities associated with citrus rhizosphere

    PubMed Central

    Trivedi, Pankaj; He, Zhili; Van Nostrand, Joy D; Albrigo, Gene; Zhou, Jizhong; Wang, Nian

    2012-01-01

    The diversity and stability of bacterial communities present in the rhizosphere heavily influence soil and plant quality and ecosystem sustainability. The goal of this study is to understand how ‘Candidatus Liberibacter asiaticus' (known to cause Huanglongbing, HLB) influences the structure and functional potential of microbial communities associated with the citrus rhizosphere. Clone library sequencing and taxon/group-specific quantitative real-time PCR results showed that ‘Ca. L. asiaticus' infection restructured the native microbial community associated with citrus rhizosphere. Within the bacterial community, phylum Proteobacteria with various genera typically known as successful rhizosphere colonizers were significantly greater in clone libraries from healthy samples, whereas phylum Acidobacteria, Actinobacteria and Firmicutes, typically more dominant in the bulk soil were higher in ‘Ca. L. asiaticus'-infected samples. A comprehensive functional microarray GeoChip 3.0 was used to determine the effects of ‘Ca. L. asiaticus' infection on the functional diversity of rhizosphere microbial communities. GeoChip analysis showed that HLB disease has significant effects on various functional guilds of bacteria. Many genes involved in key ecological processes such as nitrogen cycling, carbon fixation, phosphorus utilization, metal homeostasis and resistance were significantly greater in healthy than in the ‘Ca. L. asiaticus'-infected citrus rhizosphere. Our results showed that the microbial community of the ‘Ca. L. asiaticus'-infected citrus rhizosphere has shifted away from using more easily degraded sources of carbon to the more recalcitrant forms. Overall, our study provides evidence that the change in plant physiology mediated by ‘Ca. L. asiaticus' infection could elicit shifts in the composition and functional potential of rhizosphere microbial communities. In the long term, these fluctuations might have important implications for the productivity and sustainability of citrus-producing agro-ecosystems. PMID:21796220

  15. Lateral organ boundaries 1 is a disease susceptibility gene for citrus bacterial canker disease

    Microsoft Academic Search

    Y. Hu; J. Zhang; H. Jia; D. Sosso; T. Li; W. B. Frommer; B. Yang; F. F. White; N. Wang; J. B. Jones

    2014-01-01

    Citrus bacterial canker (CBC) disease occurs worldwide and incurs considerable costs both from control measures and yield losses. Bacteria that cause CBC require one of six known type III transcription activator-like (TAL) effector genes for the characteristic pustule formation at the site of infection. Here, we show that Xanthomonas citri subspecies citri strain Xcc306, with the type III TAL effector

  16. Properties of a Cell-Free System for Synthesis of Citrus Exocortis Viroid

    Microsoft Academic Search

    Ricardo Flores; J. S. Semancik

    1982-01-01

    Partially purified nuclei from citrus exocortis viroid (CEV)-infected Gynura aurantiaca are able to synthesize linear and circular viroid molecules. Pretreatment of the nuclei with actinomycin D or deoxyribonuclease did not affect viroid synthesis, whereas the synthesis of other cellular RNAs was severely reduced. These observations support the essential role of CEV complementary RNA sequences in viroid replication. However, when alpha

  17. Inducible proteins in citrus rootstocks with different tolerance towards the root rot pathogen Phytophthora palmivora

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Activities of defense-related proteins (ß-1,3-glucanases, chitinases and peroxidases) and concentrations of total soluble phenolics were measured in roots and leaves of uninfected and infected plants to investigate the response of different citrus rootstock genotypes to the root rot pathogen Phytoph...

  18. An update on the effect of citrus greening on flavor and taste of orange juice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There have been some anecdotal reports that Huanglongbing (HLB) or citrus greening disease, recently introduced in Florida, may impart off flavor to orange juice. It is of interest to the processing industry to determine what affect fruit from trees of various stages of infection would have on proce...

  19. Genetic differentiation and biology of Citrus Tristeza virus populations spreading in California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    CTV strains were collected from more than 1500 CTV-infected trees in citrus groves in Tulare, Kern, Ventura, Riverside and San Diego Counties to assess molecular and biological properties of CTV strains currently in California. Tests included serology with MCA13, quantitative (q) real-time Reverse ...

  20. Citrus stubborn symptom severity and Spiroplasma citri location within the tress canopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The severity of symptoms of citrus stubborn disease (CSD) within an orchard can range from mild to severe, but whether factors other than pathogen titer or duration of infection impact severity is not known. We tested the hypothesis that the canopy distribution of the pathogen, Spiroplasma citri, i...

  1. Efficacy of Citrus reticulata and Mirazid in treatment of Schistosoma mansoni

    Microsoft Academic Search

    Manal A Hamed; Mona H Hetta

    2005-01-01

    This work has been carried out to investigate the effect of Schistosoma mansoni infection on mice livers after treatment with the ethanolic extract of Citrus reticulata root or the oleo-resin extract from Myrrh of Commiphora molmol tree (Mirazid), as a new antishistosomal drug. Marker enzymes for different cell organelles were measured; succinate dehydrogenase (SDH); lactate dehydrogenase (LDH) and its isoenzymes;

  2. Citrus paradisi and Citrus sinensis flavonoids: Their influence in the defence mechanism against Penicillium digitatum

    Microsoft Academic Search

    A. Ortuño; A. Báidez; P. Gómez; M. C. Arcas; I. Porras; A. García-Lidón; J. A. Del Río

    2006-01-01

    Citrus peel is rich in flavanone glycosides and polymethoxyflavones. In view of their importance for industrial application as well as for their pharmacological properties, their content was analyzed in the mature fruits of several Citrus paradisi (grapefruit) and Citrus sinensis (orange) varieties, with a view to select the most interesting for isolation. The results shows that the Star Ruby grapefruit

  3. Field ID guide to citrus relative hosts of Asian citrus psyllid & Huanglongbing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Rutaceae family of plants includes not only species within the genus Citrus, but also several other genera and species that may not be easily recognized as having any relationship to citrus at all. However, many of these citrus relatives are used for ornamental, culinary, or religious purposes. ...

  4. Photographic Remote Sensing of Sick Citrus Trees

    NASA Technical Reports Server (NTRS)

    Gausman, H. W.

    1971-01-01

    Remote sensing with infrared color aerial photography (Kodak Ektachrome Infrared Aero 8443 film) for detecting citrus tree anomalies is described. Illustrations and discussions are given for detecting nutrient toxicity symptoms, for detecting foot rot and sooty mold fungal diseases, and for distinguishing among citrus species. Also, the influence of internal leaf structure on light reflectance, transmittance, and absorptance are considered; and physiological and environmental factors that affect citrus leaf light reflectance are reviewed briefly and illustrated.

  5. Citrus Allergy from Pollen to Clinical Symptoms

    PubMed Central

    Iorio, Rosa Anna; Del Duca, Stefano; Calamelli, Elisabetta; Pula, Chiara; Lodolini, Magda; Scamardella, Fortuna; Pession, Andrea; Ricci, Giampaolo

    2013-01-01

    Allergy to citrus fruits is often associated with pollinosis and sensitization to other plants due to a phenomenon of cross-reactivity. The aims of the present study were to highlight the cross-reactivity among citrus and the major allergenic pollens/fruits, throughout clinical and molecular investigations, and to evaluate the sensitization frequency to citrus fruits in a population of children and adults with pollinosis. We found a relevant percentage of sensitisation (39%) to citrus fruits in the patients recruited and in all of them the IgE-mediated mechanism has been confirmed by the positive response to the prick-to-prick test. RT-PCR experiments showed the expression of Cit s 1, Cit s 3 and a profilin isoform, already described in apple, also in Citrus clementine pollen. Data of multiple sequence alignments demonstrated that Citrus allergens shared high percentage identity values with other clinically relevant species (i.e. Triticum aestivum, Malus domestica), confirming the possible cross-allergenicity citrus/grasses and citrus/apple. Finally, a novelty of the present work has been the expression of two phospholipaseA2 isoforms (PLA2 ? and ?) in Citrus as well as in Triticum pollens; being PLA2 able to generate pro-inflammatory factors, this enzyme could participate in the activation of the allergenic inflammatory cascade. PMID:23308273

  6. Rice hull smoke extract protects mice against a salmonella lipopolysaccharide-induced endotoxemia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice hulls accounting for 20% of the rice crop are a byproduct of post-harvest rice processing. Endotoxemia (sepsis, septic shock) is an inflammatory, virulent often fatal disease that results mainly from infection with Salmonella and other Gram-negative bacteria. The present study investigated the...

  7. Prophage-Mediated Dynamics of ‘Candidatus Liberibacter asiaticus’ Populations, the Destructive Bacterial Pathogens of Citrus Huanglongbing

    PubMed Central

    Zhou, Lijuan; Powell, Charles A.; Li, Wenbin; Irey, Mike; Duan, Yongping

    2013-01-01

    Prophages are highly dynamic components in the bacterial genome and play an important role in intraspecies variations. There are at least two prophages in the chromosomes of Candidatus Liberibacter asiaticus’ (Las) Floridian isolates. Las is both unculturable and the most prevalent species of Liberibacter pathogens that cause huanglongbing (HLB), a worldwide destructive disease of citrus. In this study, seven new prophage variants resulting from two hyper-variable regions were identified by screening clone libraries of infected citrus, periwinkle and psyllids. Among them, Types A and B share highly conserved sequences and localize within the two prophages, FP1 and FP2, respectively. Although Types B and C were abundant in all three libraries, Type A was much more abundant in the libraries from the Las-infected psyllids than from the Las-infected plants, and Type D was only identified in libraries from the infected host plants but not from the infected psyllids. Sequence analysis of these variants revealed that the variations may result from recombination and rearrangement events. Conventional PCR results using type-specific molecular markers indicated that A, B, C and D are the four most abundant types in Las-infected citrus and periwinkle. However, only three types, A, B and C are abundant in Las-infected psyllids. Typing results for Las-infected citrus field samples indicated that mixed populations of Las bacteria present in Floridian isolates, but only the Type D population was correlated with the blotchy mottle symptom. Extended cloning and sequencing of the Type D region revealed a third prophage/phage in the Las genome, which may derive from the recombination of FP1 and FP2. Dramatic variations in these prophage regions were also found among the global Las isolates. These results are the first to demonstrate the prophage/phage-mediated dynamics of Las populations in plant and insect hosts, and their correlation with insect transmission and disease development. PMID:24349235

  8. Investigating alternatives to traditional insecticides: effectiveness of entomopathogenic fungi and Bacillus thuringiensis against citrus thrips and avocado thrips (Thysanoptera: Thripidae).

    PubMed

    Zahn, Deane K; Morse, Joseph G

    2013-02-01

    Citrus thrips, Scirtothrips citri (Moulton) (Thysanoptera: Thripidae), is a plant-feeding pest most widely recognized for causing damage to citrus (Citrus spp. L. [Rutaceae]) and mango (Mangifera indica L. [Anacardiaceae]) fruits. This insect has recently broadened its known host range to become a significant pest of California grown blueberries. Avocado thrips, Scirtothrips. perseae Nakahara (Thysanoptera: Thripidae), is a recent, invasive pest of California avocados, Persea americana Mill. (Laurales: Lauraceae). Effective alternatives to traditional pesticides are desirable for both pests to reduce impacts on natural enemies and broaden control options in an effort to minimize pesticide resistance via rotation of control materials. We evaluated Bacillus thuringiensis (Bt) subsp. israelensis proteins (Cyt 1A and Cry 11A, activated and inactivated) and multiple strains (GHA, 1741ss, SFBb1, S44ss, NI1ss, and 3769ss) of Beauveria bassiana (Balsamo) Vuillemin against both species. Avocado thrips and citrus thrips were not susceptible to either Bt protein tested, regardless of activation status. All strains of B. bassiana were able to infect both avocado thrips and citrus thrips. However, the commercially available GHA strain was the most effective strain against both species and had a faster rate of infection then the other strains tested. Citrus thrips were more susceptible than avocado thrips to all B. bassiana strains (LC50 and LC95 of 8.6 x 10(4) and 4.8 x 10(6) conidia per ml for citrus thrips, respectively). Investigation of citrus thrips field control using the GHA strain of B. bassiana is therefore justified. PMID:23448016

  9. Brassica cover cropping for management of sheath blight of rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheath blight, caused by Rhizoctonia solani, is the most important disease limiting rice production in Texas and other rice-producing states. The fungal pathogen survives between crops as soilborne sclerotia and mycelium in infected plant debris. These sclerotia and colonized plant debris float on t...

  10. Citrus Orchard Management in Texas.

    E-print Network

    Hancock, Bluefford G.

    1962-01-01

    to observe evidence of damage b\\ pev, and diseases. Then take appropriate action. Young Citrus Orchard Cultivation Cultivation or tillage of the orchard soil is not essential. However, weeds interfere with certain grove operations and they also use watcr... is a popular ing machine. ' may be obtained by disking the soil, chop- lowing or shredding. metliotl ant1 gr; equipp~ :ing is the cheapest and most efficient of destroying a heavy growth of weeds Isses. The tandem disk harrow should be ed so...

  11. Green synthesis of gold nanoparticles using Citrus fruits (Citrus limon, Citrus reticulata and Citrus sinensis) aqueous extract and its characterization

    NASA Astrophysics Data System (ADS)

    Sujitha, Mohanan V.; Kannan, Soundarapandian

    2013-02-01

    This study reports the biological synthesis of gold nanoparticles by the reduction of HAuCl4 by using citrus fruits (Citrus limon, Citrus reticulata and Citrus sinensis) juice extract as the reducing and stabilizing agent. A various shape and size of gold nanoparticles were formed when the ratio of the reactants were altered with respect to 1.0 mM chloroauric acid solution. The gold nanoparticles obtained were characterized by UV-visible spectra, transmission electron microscopy (TEM) and X-ray diffraction (XRD). TEM studies showed the particles to be of various shapes and sizes and particle size ranges from 15 to 80 nm. Selected-area electron diffraction (SAED) pattern confirmed fcc phase and crystallinity of the particles. The X-ray diffraction analysis revealed the distinctive facets (1 1 1, 2 0 0, 2 2 0 and 2 2 2 planes) of gold nanoparticles. Dynamic light scattering (DLS) studies revealed that the average size for colloid gp3 of C. limon, C. reticulata and C. sinensis are 32.2 nm, 43.4 nm and 56.7 nm respectively. The DLS graph showed that the particles size was larger and more polydispersed compared to the one observed by TEM due to the fact that the measured size also includes the bio-organic compounds enveloping the core of the Au NPs. Zeta potential value for gold nanoparticles obtained from colloid gp3 of C. limon, C. reticulata and C. sinensis are -45.9, -37.9 and -31.4 respectively indicating the stability of the synthesized nanoparticles. Herein we propose a novel, previously unexploited method for the biological syntheses of polymorphic gold nanoparticles with potent biological applications.

  12. Transgenic sweet orange plants expressing a dermaseptin coding sequence show reduced symptoms of citrus canker disease.

    PubMed

    Furman, Nicolás; Kobayashi, Ken; Zanek, Maria Cecilia; Calcagno, Javier; Garcia, Maria Laura; Mentaberry, Alejandro

    2013-09-20

    Citrus canker provoked by Xanthomonas axonopodis pv. citri is a bacterial disease causing severe losses in all citrus-producing areas around the world. Xanthomonas infection is considered as an endemic disease in Northeast and Northwest Argentina, affecting as much as 10% of commercial citrus plantations. There is not known natural resistance neither in orange varieties nor in rootstocks used for grafting of commercial cultivars. To introduce resistance to this disease, plants of Pineapple sweet orange were transformed with a genetic construct allowing constitutive accumulation of dermaseptin. In comparison with non-transformed plants, transgenic plants showed symptom reduction levels of up to 50% in in planta assays performed under controlled conditions. PMID:23896218

  13. Alien introgression in rice

    Microsoft Academic Search

    D. S. Brar; G. S. Khush

    1997-01-01

    Rice (Oryza sativa L.) productivity is affected by several biotic and abiotic stresses. The genetic variability for some of these stresses is limited in the cultivated rice germplasm. Moreover, changes in insect biotypes and disease races are a continuing threat to increased rice production. There is thus an urgent need to broaden the rice gene pool by introgressing genes for

  14. General Announcements Rice University

    E-print Network

    Richards-Kortum, Rebecca

    General Announcements Rice University 2006­2007 #12;NOTE without notice. William Marsh Rice University Physical Address: 6100 Main Street, Houston, Texas 77005 Address: http://www.rice.edu 2006­07 General Announcements online: http://www.rice.edu/catalog/ Please

  15. General Announcements Rice University

    E-print Network

    Richards-Kortum, Rebecca

    General Announcements Rice University 2005­2006 #12;NOTE: This catalog represents the most accurate offerings are subject to change without notice. William Marsh Rice University Physical Address:6100 Main:Campus Operator 713-348-0000 Homepage Address:http://www.rice.edu 2005­2006 General Announcements online:http://www.rice

  16. Rice Young Alumni Information

    E-print Network

    Palem, Krishna V.

    Rice Young Alumni Detailed Information: Houston Young Alumni Committee Programs 2011-2012 #12; Rice Young Alumni Information Alumni.rice.edu The Houston Young Alumni Committee Helps Shape Your Young Alumni Programs The Houston Young Alumni Committee represents the over 2,300 Rice undergrad

  17. Analysis of rice blast resistance in rice breeding parents from USA using molecular markers and pathogenicity assays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice blast disease is caused by the fungal pathogen Magnaporthe oryzae. The Pi-ta gene in rice is effective in preventing infections by strains of M. oryzae that carry AVR-Pita1 in a gene for gene specificity. In the present study, two dominant markers YL153/YL154 and YL155/YL87 derived from diffe...

  18. QCM immunoassay for recombinant cysteine peptidase: a potential protein biomarker for diagnosis of citrus canker.

    PubMed

    Afonso, André S; Zanetti, Bianca F; Santiago, Adelita C; Henrique-Silva, Flavio; Mattoso, Luiz H C; Faria, Ronaldo C

    2013-01-30

    Citrus canker is one of the most important agricultural citrus diseases worldwide. It is caused by Xanthomonas citri subsp. citri (Xcc) bacterium that infects leaves and the fruits produce a cysteine peptidase (CPXaC), which makes it a potential target for the development of effective and rapid detection methods for citrus canker. We report here the studies on the development of piezoelectric immunoassay for CPXaC using a polyclonal antibody against CPXaC (anti-CPXaC). Three different strategies for covalent immobilization of anti-CPXaC on gold surfaces were evaluated by monitoring the frequency (?f) and energy dissipation (?D) variation in real time when 64.5×10(-8) mol L(-1) CPXaC was added. Anti-CPXaC immobilized with 11-mercaptoundecanoic acid (MUA) showed the best relation between the frequency and dissipation factor variation, and strong values for the kinetic and equilibrium binding constant were obtained. The immunosensor showed a detection limit of 13.0 nmol L(-1) with excellent specificity, showing no response for different proteins that include another cysteine peptidase that is used as a target to detect Xylella fastidiosa bacterium, responsible for another important citrus disease. These results provide good perspectives for the use of CPXaC as a new biomarker for citrus canker. PMID:23597909

  19. Cooperation in the Conservation of Citrus Genetic Resources: Riverside, California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A consortium of cooperating programs for the conservation and utilization of citrus genetic resources is centered at the University of California, Riverside (UCR). University units include the Citrus Clonal Protection Program (CCPP), Citrus Variety Collection (CVC), and Citrus Breeding Program (CBP...

  20. Citrus Viruses in Guatemala: Application of Laboratory-Based Assays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In preparation for a citrus certification in Guatemala, there was an urgent need to determine which graft transmissible citrus pathogens were present. Because of the lack of biological indicator plants, Citrus tristeza virus (CTV) and Xylella fastidiosa, causal agent for citrus variegated chlorosis...

  1. Circular 1461 Precision Farming Adoption by Florida Citrus Producers

    E-print Network

    Lee, Wonsuk "Daniel"

    Circular 1461 Precision Farming Adoption by Florida Citrus Producers: Probit Model Analysis1 Brian of precision technologies in citrus production. Florida citrus production has experienced a rather volatile perfectly to the production scenario in citrus. If growers were able to manage their input applications

  2. RESEARCH ARTICLE Impact of water stress on citrus yield

    E-print Network

    Paris-Sud XI, Université de

    RESEARCH ARTICLE Impact of water stress on citrus yield Iván García-Tejero & Victor Hugo Durán. This work estimates the water production function in citrus trees, determining the relationship between% crop water evapotranspiration (ETC)) were implemented in 13-year-old citrus trees (Citrus sinensis L

  3. Plant resistance within the Rutaceae to Asian citrus psyllid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    USDA-ARS recently initiated research on host plant resistance to the Asian citrus psyllid. The psyllid is an important invasive pest of citrus in the United States because it transmits a serious disease of citrus known as huanglongbing (citrus greening). There is no cure for this bacterial disease. ...

  4. HUANGLONGBING, CITRUS GREENING: PREPARING FOR THE FUTURE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB), more commonly known as citrus greening disease, was found in Florida in August 2005; Diaphorina citri Kuwayama, the Asian citrus psyllid and insect vector of HLB, was found in Florida in 1998. Since the initial discovery, the presence of HLB has been confirmed by polymerase cha...

  5. Asian citrus psyllid, genetic basis of immunity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We successfully used a genomics approach to determine some of the genes which function in immunity, stress, and insecticide resistance in the Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae). These psyllids are vectors of the devastating disease, Huanglongbing, now affecting citrus in F...

  6. Citrus Community College District Mentor Program.

    ERIC Educational Resources Information Center

    Hinds, Diane; Sprague, Caroline

    The Citrus College faculty and staff addressed the problem of lower career aspirations among women by establishing a support group, Citrus Women in Higher Education (CWHE). In addition to group meetings and special programs of interest, the CWHE has developed a mentor program to address the problem of blocked careers faced by women. The goals of…

  7. Rice ( Oryza) hemoglobins

    PubMed Central

    Arredondo-Peter, Raúl; Moran, Jose F.; Sarath, Gautam

    2014-01-01

    Hemoglobins (Hbs) corresponding to non-symbiotic (nsHb) and truncated (tHb) Hbs have been identified in rice ( Oryza). This review discusses the major findings from the current studies on rice Hbs. At the molecular level, a family of the nshb genes, consisting of hb1, hb2, hb3, hb4 and hb5, and a single copy of the thb gene exist in Oryza sativa var. indica and O. sativa var. japonica, Hb transcripts coexist in rice organs and Hb polypeptides exist in rice embryonic and vegetative organs and in the cytoplasm of differentiating cells. At the structural level, the crystal structure of rice Hb1 has been elucidated, and the structures of the other rice Hbs have been modeled. Kinetic analysis indicated that rice Hb1 and 2, and possibly rice Hb3 and 4, exhibit a very high affinity for O 2, whereas rice Hb5 and tHb possibly exhibit a low to moderate affinity for O 2. Based on the accumulated information on the properties of rice Hbs and data from the analysis of other plant and non-plant Hbs, it is likely that Hbs play a variety of roles in rice organs, including O 2-transport, O 2-sensing, NO-scavenging and redox-signaling. From an evolutionary perspective, an outline for the evolution of rice Hbs is available. Rice nshb and thb genes vertically evolved through different lineages, rice nsHbs evolved into clade I and clade II lineages and rice nshbs and thbs evolved under the effect of neutral selection. This review also reveals lacunae in our ability to completely understand rice Hbs. Primary lacunae are the absence of experimental information about the precise functions of rice Hbs, the properties of modeled rice Hbs and the cis-elements and trans-acting factors that regulate the expression of rice hb genes, and the partial understanding of the evolution of rice Hbs. PMID:25653837

  8. Rice Insect Management.

    E-print Network

    Drees, Bastiaan M.

    1983-01-01

    stink bugs migragring into rice from declining alternate host plants. "Extemioll elltom%gist . The T exas A&M UI/it 'ersity Syst em . -3- Fertilization practices also affect yield reductions crushed by rice water weevil larval populations. Rice... feeding. Resistance may result from plant characteristics which make certain varieties less attractive to pests than others. Weed control practices can reduce the number of alternate hosts in a rice field. Rice stink bug populations build up on other...

  9. Effective Antibiotics against ‘Candidatus Liberibacter asiaticus’ in HLB-Affected Citrus Plants Identified via the Graft-Based Evaluation

    PubMed Central

    Powell, Charles A.; Doud, Melissa S.; Yang, Chuanyu; Duan, Yongping

    2014-01-01

    Citrus huanglongbing (HLB), caused by three species of fastidious, phloem-limited ‘Candidatus Liberibacter’, is one of the most destructive diseases of citrus worldwide. To date, there is no established cure for this century-old and yet, newly emerging disease. As a potential control strategy for citrus HLB, 31 antibiotics were screened for effectiveness and phytotoxicity using the optimized graft-based screening system with ‘Candidatus Liberibacter asiaticus’ (Las)-infected citrus scions. Actidione and Oxytetracycline were the most phytotoxic to citrus with less than 10% of scions surviving and growing; therefore, this data was not used in additional analyses. Results of principal component (PCA) and hierarchical clustering analyses (HCA) demonstrated that 29 antibiotics were clustered into 3 groups: highly effective, partly effective, and not effective. In spite of different modes of actions, a number of antibiotics such as, Ampicillin, Carbenicillin, Penicillin, Cefalexin, Rifampicin and Sulfadimethoxine were all highly effective in eliminating or suppressing Candidatus Liberibacter asiaticus indicated by both the lowest Las infection rate and titers of the treated scions and inoculated rootstock. The non-effective group, including 11 antibiotics alone with three controls, such as Amikacin, Cinoxacin, Gentamicin, Kasugamycin, Lincomycin, Neomycin, Polymixin B and Tobramycin, did not eliminate or suppress Las in the tested concentrations, resulting in plants with increased titers of Las. The other 12 antibiotics partly eliminated or suppressed Las in the treated and graft-inoculated plants. The effective and non-phytotoxic antibiotics could be potential candidates for control of citrus HLB, either for the rescue of infected citrus germplasm or for restricted field application. PMID:25372135

  10. Small RNA profiling reveals phosphorus deficiency as a contributing factor in symptom expression for citrus huanglongbing disease.

    PubMed

    Zhao, Hongwei; Sun, Ruobai; Albrecht, Ute; Padmanabhan, Chellappan; Wang, Airong; Coffey, Michael D; Girke, Thomas; Wang, Zonghua; Close, Timothy J; Roose, Mikeal; Yokomi, Raymond K; Folimonova, Svetlana; Vidalakis, Georgios; Rouse, Robert; Bowman, Kim D; Jin, Hailing

    2013-03-01

    Huanglongbing (HLB) is a devastating citrus disease that is associated with bacteria of the genus 'Candidatus Liberibacter' (Ca. L.). Powerful diagnostic tools and management strategies are desired to control HLB. Host small RNAs (sRNA) play a vital role in regulating host responses to pathogen infection and are used as early diagnostic markers for many human diseases, including cancers. To determine whether citrus sRNAs regulate host responses to HLB, sRNAs were profiled from Citrus sinensis 10 and 14 weeks post grafting with Ca. L. asiaticus (Las)-positive or healthy tissue. Ten new microRNAs (miRNAs), 76 conserved miRNAs, and many small interfering RNAs (siRNAs) were discovered. Several miRNAs and siRNAs were highly induced by Las infection, and can be potentially developed into early diagnosis markers of HLB. miR399, which is induced by phosphorus starvation in other plant species, was induced specifically by infection of Las but not Spiroplasma citri that causes citrus stubborn-a disease with symptoms similar to HLB. We found a 35% reduction of phosphorus in Las-positive citrus trees compared to healthy trees. Applying phosphorus oxyanion solutions to HLB-positive sweet orange trees reduced HLB symptom severity and significantly improved fruit production during a 3-year field trial in south-west Florida. Our molecular, physiological, and field data suggest that phosphorus deficiency is linked to HLB disease symptomology. PMID:23292880

  11. Small RNA Profiling Reveals Phosphorus Deficiency as a Contributing Factor in Symptom Expression for Citrus Huanglongbing Disease

    PubMed Central

    Zhao, Hongwei; Sun, Ruobai; Jin, Hailing

    2013-01-01

    Huanglongbing (HLB) is a devastating citrus disease that is associated with bacteria of the genus ‘Candidatus Liberibacter’ (Ca. L.). Powerful diagnostic tools and management strategies are desired to control HLB. Host small RNAs (sRNA) play a vital role in regulating host responses to pathogen infection and are used as early diagnostic markers for many human diseases, including cancers. To determine whether citrus sRNAs regulate host responses to HLB, sRNAs were profiled from Citrus sinensis 10 and 14 weeks post grafting with Ca. L. asiaticus (Las)-positive or healthy tissue. Ten new microRNAs (miRNAs), 76 conserved miRNAs, and many small interfering RNAs (siRNAs) were discovered. Several miRNAs and siRNAs were highly induced by Las infection, and can be potentially developed into early diagnosis markers of HLB. miR399, which is induced by phosphorus starvation in other plant species, was induced specifically by infection of Las but not Spiroplasma citri that causes citrus stubborn—a disease with symptoms similar to HLB. We found a 35% reduction of phosphorus in Las-positive citrus trees compared to healthy trees. Applying phosphorus oxyanion solutions to HLB-positive sweet orange trees reduced HLB symptom severity and significantly improved fruit production during a 3-year field trial in south-west Florida. Our molecular, physiological, and field data suggest that phosphorus deficiency is linked to HLB disease symptomology. PMID:23292880

  12. Hang.Yu@rice.edu lzhong@rice.edu

    E-print Network

    Zhong, Lin

    Hang Yu Hang.Yu@rice.edu Lin Zhong lzhong@rice.edu Ashutosh Sabharwal ashu@rice.edu Department of Electrical & Computer Engineering, Rice University, Houston, TX 77005 All current mobile devices are omni

  13. A COMPARISON OF TRAPS AND TAP SAMPLING FOR MONITORING ADULT ASIAN CITRUS PSYLLID, DIAPHORINA CITRI KUWAYMA (HOMOPTERA: PSYLLIDAE), IN CITRUS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid, Diaphorina citri Kuwayama, was first found in Florida during June 1998 and subsequently spread throughout the state's citrus-growing regions. D. citri vectors the bacterium, Candidatus Liberibacter asiaticus, responsible for citrus greening disease (huanglongbing). Citrus g...

  14. Citrus quarantine, sanitary and certification programs in the USA. Prevention of introduction and distribution of citrus diseases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus germplasm originated in Australasia, the Far East, and Africa, thus all citrus grown in the New World was imported. This importation of citrus also resulted in importation of graft transmissible pathogens of citrus, many of which are latent in their original host but can cause epidemics of t...

  15. Transcriptome Profiling of Citrus Fruit Response to Huanglongbing Disease

    PubMed Central

    Martinelli, Federico; Uratsu, Sandra L.; Albrecht, Ute; Reagan, Russell L.; Phu, My L.; Britton, Monica; Buffalo, Vincent; Fass, Joseph; Leicht, Elizabeth; Zhao, Weixiang; Lin, Dawei; D'Souza, Raissa; Davis, Cristina E.; Bowman, Kim D.; Dandekar, Abhaya M.

    2012-01-01

    Huanglongbing (HLB) or “citrus greening” is the most destructive citrus disease worldwide. In this work, we studied host responses of citrus to infection with Candidatus Liberibacter asiaticus (CaLas) using next-generation sequencing technologies. A deep mRNA profile was obtained from peel of healthy and HLB-affected fruit. It was followed by pathway and protein-protein network analysis and quantitative real time PCR analysis of highly regulated genes. We identified differentially regulated pathways and constructed networks that provide a deep insight into the metabolism of affected fruit. Data mining revealed that HLB enhanced transcription of genes involved in the light reactions of photosynthesis and in ATP synthesis. Activation of protein degradation and misfolding processes were observed at the transcriptomic level. Transcripts for heat shock proteins were down-regulated at all disease stages, resulting in further protein misfolding. HLB strongly affected pathways involved in source-sink communication, including sucrose and starch metabolism and hormone synthesis and signaling. Transcription of several genes involved in the synthesis and signal transduction of cytokinins and gibberellins was repressed while that of genes involved in ethylene pathways was induced. CaLas infection triggered a response via both the salicylic acid and jasmonic acid pathways and increased the transcript abundance of several members of the WRKY family of transcription factors. Findings focused on the fruit provide valuable insight to understanding the mechanisms of the HLB-induced fruit disorder and eventually developing methods based on small molecule applications to mitigate its devastating effects on fruit production. PMID:22675433

  16. Postharvest decay control of citrus fruit by preharvest pyrimethanil spray.

    PubMed

    D'Aquino, S; Angioni, A; Suming, D; Palma, A; Schirra, M

    2013-01-01

    Preharvest infections or conidia load on fruit surface by Penicillium digitatum, P. italicum, Alternaria citri and other filamentous fungi can cause important postharvest losses of citrus fruit. Reduction in pruning frequency occurred in the last decade together with un-picked yield that eventually rots on the trees have increased the risk of postharvest decay especially when environmental conditions at picking time are favourable to pathogens' development. Sanitation procedures in the packinghouses, alternate use of postharvest fungicides with different modes of action, along with fungicide application before harvest could be an effective approach to minimize postharvest decay in citrus fruit. The present study investigated the effectiveness of a preharvest treatment with pyrimethanil (PYR), a broad spectrum fungicide, recently registered in different citrus-producing countries for postharvest treatments of citrus fruit and widely used worldwide as a preharvest treatment to control various diseases in different crops. PYR (750 mg/L) was sprayed by a hand-back sprayer at run-off on 'Fremont' mandarins. The day after the treatment, half of the trees were sprayed with a 10(4) conidial suspension of P. digitatum at run-off. Fruit were harvested following 2 or 4 weeks from treatments. Sound or either wounded 2-mm-deep and 2-mm-wide or superficial wound-scratched fruit were stored at 20 degrees C and 90% RH and inspected for decay after 1, 2 or 3 weeks of storage. In fruit harvested after 2 weeks from field treatment, PYR remarkably reduced decay development during two weeks of storage in sound fruit and in wound-scratched fruit and was fairly effective even after 4 weeks from treatment, but was ineffective in fruit wounded 2 mm deep and 2 mm wide. PYR was also effective in reducing preharvest decay incited by P. digitatum, P. italicum and Botrytis cinerea, but not by other pathogens. Results show that preharvest treatment with PYR could be a feasible approach to reduce postharvest chemical control of decay of citrus fruit. PMID:25145229

  17. Leadership Rice Leadership Rice exists to encourage and equip Rice students to obtain significant

    E-print Network

    Richards-Kortum, Rebecca

    206 Leadership Rice Leadership Rice exists to encourage and equip Rice students to obtain significant leadership roles at Rice and beyond. We provide leadership development opportunities capacity and strongest ambition for significant leadership. We seek to accomplish our mission through

  18. Isolation and identification of citrus psorosis virus Egyptian isolate (CPsV-EG).

    PubMed

    Ghazal, S A; El-Dougdoug, Kh A; Mousa, A A; Fahmy, H; Sofy, A R

    2008-01-01

    Citrus psorosis ophiovirus (CPsV), is considered to be of the most serious and deter mental virus pathogen's citrus species trees in Egypt. CPsV-EG was isolated from infected citrus grapefruit (C. paradisi Macf.) at Agric. Res. Centre (ARC). The grapefruit which used for CPsV-EG isolate was found to be free from CTV, CEVd and Spiroplasma citri where as gave -ve results with DTBIA, tissue print hybridization and Diene's stain respectively. CPsV-EG was detected on the basis of biological indexing by graft inoculation which gave oak leaf pattern (OLP) on Dweet tangor and serological assay by DAS-ELISA using Mab specific CPsV. CPsV-EG was reacted with variable responses on 16 host plants belonging to 6 families. Only 8 host plants are susceptible and showed visible external symptoms which appeared as local, systemic and local followed by systemic infections. CPsV-EG isolate was transmitted from infected citrus to citrus by syringe and grafting and herbaceous plants by forefinger inoculation and syringe. The woody indicators and rootstocks were differed in response to CPsV-EG isolate which appeared as no-response, response, sensitivity and hypersensitivity. The serological characters represented as the antigenic determinants of CPsV-EG isolate related to monoclonal antibodies specific CPsV strain where as appeared precipitation reaction by DAS-ELISA and DTBIA. The partial fragment of RNA3 (coat protein gene) of CPsV-EG (-1140bp and -571bp) was amplified by reverse transcription-polymerase chain reaction (RT-PCR) from grapefruit tissues using two sets primers specific CPsV (CPV3 and CPV4) and (PS66 and PS65) respectively. The virus under study was identified as CPsV-EG isolate according to biological, serological and molecular characters. PMID:19226765

  19. Chipping citrus wood for gasifiction

    SciTech Connect

    Churchill, D.B.; Hedden, S.L.; Whitney, J.D.; Shaw, L.N.

    1984-01-01

    Both green and dead citrus trees were used for chipping. Chip moisture content, fuel analysis, drying time, and data on fuel/tonne of chips were obtained. The average moisture contents of green and dead trees when chipped were 25% and 16% (wet basis) respectively. Chips were sized to a minimum of 0.32 squared cm x 0.32 cm thick to a maximum of 5.0 cm squared x 0.32 cm thick and normally required 4 weeks to air dry to 14% (wet basis) moisture content before use. Approximately 50% of the total tree by weight could be made into usable chips. 9 references.

  20. 7 CFR 905.149 - Procedure for permitting growers to ship tree run citrus fruit.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...false Procedure for permitting growers to ship tree run citrus fruit. 905.149 Section 905.149...149 Procedure for permitting growers to ship tree run citrus fruit. (a) Tree run citrus fruit. Tree run citrus fruit as...

  1. 7 CFR 905.149 - Procedure for permitting growers to ship tree run citrus fruit.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...false Procedure for permitting growers to ship tree run citrus fruit. 905.149 Section 905.149...149 Procedure for permitting growers to ship tree run citrus fruit. (a) Tree run citrus fruit. Tree run citrus fruit as...

  2. 7 CFR 905.149 - Procedure for permitting growers to ship tree run citrus fruit.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...false Procedure for permitting growers to ship tree run citrus fruit. 905.149 Section 905.149...149 Procedure for permitting growers to ship tree run citrus fruit. (a) Tree run citrus fruit. Tree run citrus fruit as...

  3. 7 CFR 905.149 - Procedure for permitting growers to ship tree run citrus fruit.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...false Procedure for permitting growers to ship tree run citrus fruit. 905.149 Section 905.149...149 Procedure for permitting growers to ship tree run citrus fruit. (a) Tree run citrus fruit. Tree run citrus fruit as...

  4. 7 CFR 905.149 - Procedure for permitting growers to ship tree run citrus fruit.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...false Procedure for permitting growers to ship tree run citrus fruit. 905.149 Section 905.149...149 Procedure for permitting growers to ship tree run citrus fruit. (a) Tree run citrus fruit. Tree run citrus fruit as...

  5. Physiological changes associated with senescence and abscission in mature citrus fruit induced by 5-chloro-3-

    E-print Network

    Burns, Jacqueline K.

    Physiological changes associated with senescence and abscission in mature citrus fruit induced by 5 K. Burns* Horticultural Sciences Department, Citrus Research and Education Center, University), a plant growth regulator that selectively promotes abscission in mature citrus fruit (Citrus sinensis

  6. 7 CFR 93.5 - Fees for citrus product analyses set by cooperative agreement.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Fees for citrus product analyses set by cooperative agreement...TESTING PROGRAMS PROCESSED FRUITS AND VEGETABLES Citrus Juices and Certain Citrus Products § 93.5 Fees for citrus product...

  7. 7 CFR 93.5 - Fees for citrus product analyses set by cooperative agreement.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Fees for citrus product analyses set by cooperative agreement...TESTING PROGRAMS PROCESSED FRUITS AND VEGETABLES Citrus Juices and Certain Citrus Products § 93.5 Fees for citrus product...

  8. 7 CFR 93.5 - Fees for citrus product analyses set by cooperative agreement.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 2011-01-01 false Fees for citrus product analyses set by cooperative agreement...TESTING PROGRAMS PROCESSED FRUITS AND VEGETABLES Citrus Juices and Certain Citrus Products § 93.5 Fees for citrus product...

  9. 7 CFR 93.5 - Fees for citrus product analyses set by cooperative agreement.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Fees for citrus product analyses set by cooperative agreement...TESTING PROGRAMS PROCESSED FRUITS AND VEGETABLES Citrus Juices and Certain Citrus Products § 93.5 Fees for citrus product...

  10. 7 CFR 93.5 - Fees for citrus product analyses set by cooperative agreement.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Fees for citrus product analyses set by cooperative agreement...TESTING PROGRAMS PROCESSED FRUITS AND VEGETABLES Citrus Juices and Certain Citrus Products § 93.5 Fees for citrus product...

  11. Comprehensive analysis of CCCH-type zinc finger gene family in citrus (Clementine mandarin) by genome-wide characterization.

    PubMed

    Liu, Shengrui; Khan, Muhammad Rehman Gul; Li, Yongping; Zhang, Jinzhi; Hu, Chungen

    2014-10-01

    The CCCH-type zinc finger proteins comprise a large gene family of regulatory proteins and are widely distributed in eukaryotic organisms. The CCCH proteins have been implicated in multiple biological processes and environmental responses in plants. Little information is available, however, about CCCH genes in plants, especially in woody plants such as citrus. The release of the whole-genome sequence of citrus allowed us to perform a genome-wide analysis of CCCH genes and to compare the identified proteins with their orthologs in model plants. In this study, 62 CCCH genes and a total of 132 CCCH motifs were identified, and a comprehensive analysis including the chromosomal locations, phylogenetic relationships, functional annotations, gene structures and conserved motifs was performed. Distribution mapping revealed that 54 of the 62 CCCH genes are unevenly dispersed on the nine citrus chromosomes. Based on phylogenetic analysis and gene structural features, we constructed 5 subfamilies of 62 CCCH members and integrative subfamilies from citrus, Arabidopsis, and rice, respectively. Importantly, large numbers of SNPs and InDels in 26 CCCH genes were identified from Poncirus trifoliata and Fortunella japonica using whole-genome deep re-sequencing. Furthermore, citrus CCCH genes showed distinct temporal and spatial expression patterns in different developmental processes and in response to various stress conditions. Our comprehensive analysis of CleC3Hs is a valuable resource that further elucidates the roles of CCCH family members in plant growth and development. In addition, variants and comparative genomics analyses deepen our understanding of the evolution of the CCCH gene family and will contribute to further genetics and genomics studies of citrus and other plant species. PMID:24820208

  12. Citrus Cachexia Viroid, a New Viroid of Citrus: Relationship to Viroids of the Exocortis Disease Complex

    Microsoft Academic Search

    J. S. Semancik; C. N. Roistacher; R. Rivera-Bustamante; N. Duran-Vila

    1988-01-01

    SUMMARY Recovery of highly purified citrus cachexia viroid (CCaV) was accomplished by serial elution following CF-11 cellulose chromatography of a 2 i-LiCl-soluble nucleic acid preparation. The alternative herbaceous host, cucumber (Cucumis sativus cv. Suyo), yielded greater quantities of the viroid than the highest yielding citrus host, citron (Citrus medica cv. Etrog). A randomly primed cDNA probe to CCaV purified from

  13. Consumer demand patterns for fresh citrus and citrus products in Houston, Texas

    E-print Network

    Stack, Thomas N

    1951-01-01

    CONSUME'R DLMAND PATTIJUlS FOR FRESH CITRUS AND CITRUS PRODUCTS LN HOUSTON~ TEXAS THOMAS N. STACK I A Thesis Submitted to the Graduate School of the Agricultural and Mechanical College of Texas in partial fulfillment of the requirements... for the degree of MASTFR OF SCIENCE MAJOR SUBJECT: AGRICULTURAL ECONOMICS January 1951 COHSl&KR DE?AND PATTERNS FOR FEDASH CITRUS AND CITRUS PRODUCTS IN HOUSTON~ TEXAS THGHAS N. STACK Appeoved as to style and content by C of CaesLtttee kcknovledgement...

  14. Characterization of the Asian Citrus Psyllid Transcriptome.

    PubMed

    Reese, Justin; Christenson, Matthew K; Leng, Nan; Saha, Surya; Cantarel, Brandi; Lindeberg, Magdalen; Tamborindeguy, Cecilia; Maccarthy, Justin; Weaver, Daniel; Trease, Andrew J; Steven V, Ready; Davis, Vincent M; McCormick, Courtney; Haudenschild, Christian; Han, Shunsheng; Johnson, Shannon L; Shelby, Kent S; Huang, Hong; Bextine, Blake R; Shatters, Robert G; Hall, David G; Davis, Paul H; Hunter, Wayne B

    2014-01-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is a vector for the causative agents of Huanglongbing, which threatens citrus production worldwide. This study reports and discusses the first D. citri transcriptomes, encompassing the three main life stages of D. citri, egg, nymph and adult. The transcriptomes were annotated using Gene Ontology (GO) and insecticide-related genes within each life stage were identified to aid the development of future D. citri insecticides. Transcriptome assemblies and other sequence data are available for download at the International Asian Citrus Psyllid Genome Consortium website [http://psyllid.org/download] and at NCBI [http://www.ncbi.nlm.nih.gov/bioproject/29447]. PMID:24511328

  15. Characterization of the Asian Citrus Psyllid Transcriptome

    PubMed Central

    Reese, Justin; Christenson, Matthew K.; Leng, Nan; Saha, Surya; Cantarel, Brandi; Lindeberg, Magdalen; Tamborindeguy, Cecilia; MacCarthy, Justin; Weaver, Daniel; Trease, Andrew J.; Ready, Steven V.; Davis, Vincent M.; McCormick, Courtney; Haudenschild, Christian; Han, Shunsheng; Johnson, Shannon L.; Shelby, Kent S.; Huang, Hong; Bextine, Blake R.; Shatters, Robert G.; Hall, David G.; Davis, Paul H.; Hunter, Wayne B.

    2014-01-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is a vector for the causative agents of Huanglongbing, which threatens citrus production worldwide. This study reports and discusses the first D. citri transcriptomes, encompassing the three main life stages of D. citri, egg, nymph and adult. The transcriptomes were annotated using Gene Ontology (GO) and insecticide-related genes within each life stage were identified to aid the development of future D. citri insecticides. Transcriptome assemblies and other sequence data are available for download at the International Asian Citrus Psyllid Genome Consortium website [http://psyllid.org/download] and at NCBI [http://www.ncbi.nlm.nih.gov/bioproject/29447]. PMID:24511328

  16. Global efforts in managing rice blast disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice blast disease caused by the fungus Magnaporthe oryzae is a major destructive disease threatening global food security. Resistance (R) genes to M. oryzae are effective in preventing infections by strains of M. oryzae carry the corresponding avirulence (AVR) genes. Effectiveness of genetic resist...

  17. Transformation of rice mediated by Agrobacterium tumefaciens

    Microsoft Academic Search

    Yukoh Hiei; Toshihiko Komari; Tomoaki Kubo

    1997-01-01

    Agrobacterium tumefaciens has been routinely utilized in gene transfer to dicotyledonous plants, but monocotyledonous plants including important cereals were thought to be recalcitrant to this technology as they were outside the host range of crown gall. Various challenges to infect monocotyledons including rice with Agrobacterium had been made in many laboratories, but the results were not conclusive until recently. Efficient

  18. Diversity of endophytic bacterial populations and their interaction with Xylella fastidiosa in citrus plants.

    PubMed

    Araújo, Welington L; Marcon, Joelma; Maccheroni, Walter; Van Elsas, Jan Dirk; Van Vuurde, Jim W L; Azevedo, João Lúcio

    2002-10-01

    Citrus variegated chlorosis (CVC) is caused by Xylella fastidiosa, a phytopathogenic bacterium that can infect all Citrus sinensis cultivars. The endophytic bacterial communities of healthy, resistant, and CVC-affected citrus plants were studied by using cultivation as well as cultivation-independent techniques. The endophytic communities were assessed in surface-disinfected citrus branches by plating and denaturing gradient gel electrophoresis (DGGE). Dominant isolates were characterized by fatty-acid methyl ester analysis as Bacillus pumilus, Curtobacterium flaccumfaciens, Enterobacter cloacae, Methylobacterium spp. (including Methylobacterium extorquens, M. fujisawaense, M. mesophilicum, M. radiotolerans, and M. zatmanii), Nocardia sp., Pantoea agglomerans, and Xanthomonas campestris. We observed a relationship between CVC symptoms and the frequency of isolation of species of Methylobacterium, the genus that we most frequently isolated from symptomatic plants. In contrast, we isolated C. flaccumfaciens significantly more frequently from asymptomatic plants than from those with symptoms of CVC while P. agglomerans was frequently isolated from tangerine (Citrus reticulata) and sweet-orange (C. sinensis) plants, irrespective of whether the plants were symptomatic or asymptomatic or showed symptoms of CVC. DGGE analysis of 16S rRNA gene fragments amplified from total plant DNA resulted in several bands that matched those from the bacterial isolates, indicating that DGGE profiles can be used to detect some endophytic bacteria of citrus plants. However, some bands had no match with any isolate, suggesting the occurrence of other, nonculturable or as yet uncultured, endophytic bacteria. A specific band with a high G+C ratio was observed only in asymptomatic plants. The higher frequency of C. flaccumfaciens in asymptomatic plants suggests a role for this organism in the resistance of plants to CVC. PMID:12324338

  19. Foliar application of biofilm formation-inhibiting compounds enhances control of citrus canker caused by Xanthomonas citri subsp. citri.

    PubMed

    Li, Jinyun; Wang, Nian

    2014-02-01

    Citrus canker caused by the bacterium Xanthomonas citri subsp. citri is an economically important disease of citrus worldwide. Biofilm formation plays an important role in early infection of X. citri subsp. citri on host leaves. In this study, we assessed the hypothesis that small molecules inhibiting biofilm formation reduce X. citri subsp. citri infection and enhance the control of citrus canker disease. D-leucine and 3-indolylacetonitrile (IAN) were found to prevent biofilm formation by X. citri subsp. citri on different abiotic surfaces and host leaves at a concentration lower than the minimum inhibitory concentration (MIC). Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis indicated that IAN repressed expression of chemotaxis/motility-related genes in X. citri subsp. citri. In laboratory experiments, planktonic and biofilm cells of X. citri subsp. citri treated with D-leucine and IAN, either alone or in combination, were more susceptible to copper (CuSO4) than those untreated. In greenhouse assays, D-leucine and IAN applied alone or combined with copper reduced both the number of canker lesions and bacterial populations of X. citri subsp. citri on citrus host leaves. This study provides the basis for the use of foliar-applied biofilm inhibitors for the control of citrus canker alone or combined with copper-based bactericides. PMID:23901828

  20. SCREENING CITRUS GERMPLASM FOR RESISTANCE TO XANTHORMONOS AXONOPODIS PV.CTRI

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus bacterial canker (causal agent Xanthomonas axonopodis pv. citri (Xac)) is a serious threat to the citrus industry. Currently there are no effective means to control citrus canker. Our objective was to determine the resistance of selected Citrus species, citrus hybrids, and citrus relatives to...

  1. Southern rice black-streaked dwarf virus: a white-backed planthopper-transmitted fijivirus threatening rice production in Asia.

    PubMed

    Zhou, Guohui; Xu, Donglin; Xu, Dagao; Zhang, Maoxin

    2013-01-01

    Southern rice black-streaked dwarf virus (SRBSDV), a non-enveloped icosahedral virus with a genome of 10 double-stranded RNA segments, is a novel species in the genus Fijivirus (family Reoviridae) first recognized in 2008. Rice plants infected with this virus exhibit symptoms similar to those caused by Rice black-streaked dwarf virus. Since 2009, the virus has rapidly spread and caused serious rice losses in East and Southeast Asia. Significant progress has been made in recent years in understanding this disease, especially about the functions of the viral genes, rice-virus-insect interactions, and epidemiology and control measures. The virus can be efficiently transmitted by the white-backed planthopper (WBPH, Sogatella furcifera) in a persistent circulative propagative manner but cannot be transmitted by the brown planthopper (Nilaparvata lugens) and small brown planthopper (Laodelphax striatellus). Rice, maize, Chinese sorghum (Coix lacryma-jobi) and other grass weeds can be infected via WBPH. However, only rice plays a major role in the virus infection cycle because of the vector's preference. In Southeast Asia, WBPH is a long-distance migratory rice pest. The disease cycle can be described as follows: SRBSDV and its WBPH vector overwinter in warm tropical or sub-tropical areas; viruliferous WBPH adults carry the virus from south to north via long-distance migration in early spring, transmit the virus to rice seedlings in the newly colonized areas, and lay eggs on the infected seedlings; the next generation of WBPHs propagate on infected seedlings, become viruliferous, disperse, and cause new disease outbreaks. Several molecular and serological methods have been developed to detect SRBSDV in plant tissues and individual insects. Control measures based on protection from WBPH, including seedbed coverage, chemical seed treatments, and chemical spraying of seedlings, have proven effective in China. PMID:24058362

  2. New Breeding Parents Containing Novel QTL for Rice Sheath Blight Resistance Identified by Combining Phenotypic and Molecular Characterizations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice Sheath Blight (SB) disease, caused by the necrotrophic Rhizoctonia solani Kühn, is a global and annual cause of rice yield losses. Several QTL with small individual impact must be combined to create rice varieties tolerant of SB infection because no single gene confers complete resistance. Mo...

  3. Pathogenicity of Penicillium digitatum is associated with the suppression of the defense-related hydrogen peroxide burst in citrus fruit

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The high susceptibility of citrus fruit to green mold disease and lack of resistance responses suggest that P. digitatum has the ability to suppress host defenses. The current study demonstrated that during infection, P. digitatum suppresses the defense-related oxidative burst in host cells. In co...

  4. Pre-symptomatic fibrous root decline in citrus trees caused by huanglongbing and potential interaction with Phytophthora spp.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) caused by Candidatus Liberibacter asiaticus (Las) was first detected in Florida in late 2005 and is now widely distributed throughout the commercial citrus-growing regions. In recent seasons, concurrent with freeze and drought episodes, symptomatic HLB-infected trees were much mo...

  5. PESTICIDE POISONINGS REPORTED BY FLORIDA CITRUS FIELDWORKERS

    EPA Science Inventory

    In a 1981 survey of 1811 Florida citrus fieldworkers, 25 pesticide related poisoning incidents involving 29 fieldworkers were reported. Suspected poisonings were categorized into possible and confirmed poisonings, and from these reports it was possible to project an estimated 438...

  6. General Announcements Rice University

    E-print Network

    Richards-Kortum, Rebecca

    General Announcements Rice University 2004­2005 #12;NOTE: This catalog represents the most accurate notice. William Marsh Rice University Physical Address:6100 Main Street,Houston,Texas 77005 Mailing Address:P.O.Box 1892,Houston,Texas 77251­1892 Telephone:Campus Operator 713-348-0000 Homepage Address:http://www.rice

  7. The Recursion . . . Extended Rice . . .

    E-print Network

    Gallier, Jean

    The Recursion . . . Extended Rice . . . Creative and . . . Home Page Title Page Page 388 of 405 Go . . . Extended Rice . . . Creative and . . . Home Page Title Page Page 389 of 405 Go Back Full Screen Close Quit Rice . . . Creative and . . . Home Page Title Page Page 390 of 405 Go Back Full Screen Close Quit

  8. RICE UNIVERSITY Houston, Texas

    E-print Network

    Pentus, Mati

    RICE UNIVERSITY Houston, Texas Hierarchical Attribute Grammars: Dialects, Applications and Evaluation Algorithms by Alan Carle carle@cs.rice.edu A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy May, 1992 Rice University Department of Computer Science

  9. Citrus Preferences Among Customers of Selected Stores.

    E-print Network

    Bitting, H. Wayne; Bayton, James A.; Fugett, Kenneth A.

    1950-01-01

    SYSTEM GIBB GILCHRIST, Chancellor [Blank Page in Original Bulletin] Digest Texas citrus growers, shippers and processors are confronted with a competitive struggle if they are to maintain a fair re- turn on their investment, in comparison with other... citrus pro- ducing areas. If the expansion of the frozen orange juice con- centrate industry continues a~ recently evident, canners of single strength juices and handlers of fresh fruit will face stronger competition for consumer sales. Maintenance...

  10. Ecoport Slide Shows on the Internet Related to Citrus and Citrus Diseases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The EcoPort website was launched in 2000 to provide a knowledge database of biodiversity. As of September 2005, the EcoPort website contained over one half million references, over 42,000 pictures and over 200 slide shows, of which 59 pertain to citrus and citrus virus and virus-like diseases. As ...

  11. Citrus huanglongbing shapes the structure of bacterial community associated with citrus roots

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To examine the effect of pathogen on the diversity and structure of plant associated bacterial community, we carried out a molecular based analysis using citrus and huanglongbing as host-disease model. 16S rDNA clone library analysis of the citrus roots revealed shifts in the microbial diversity in ...

  12. Freeze response of citrus and citrus-related genotypes in a Florida field planting

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A test population consisting of progenies of 92 seed-source genotypes (hereafter called “parent genotypes”) of citrus and citrus relatives in the field in East-central Florida was assessed following natural freeze events in the winters of 2010 and 2011. Eight seedlings per parent genotype were plant...

  13. ASIAN CITRUS PSYLLID AND CITRUS GREENING - A CLOSER LOOK AT THE VECTOR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Homoptera: Psyllidae), was first found in Florida during June 1998 and is now widespread throughout much of the state. This invasive psyllid vectors the bacterium responsible for huanglongbing (HLB) (greening disease), a serious citrus disease. HL...

  14. Citrus County Schools Copyright Guidelines Recommended by the Citrus County Association of School Media Specialists.

    ERIC Educational Resources Information Center

    Citrus County School District, Inverness, FL.

    This document contains copyright guidelines determined appropriate for the Citrus County School System (Florida) by the Citrus County Association of School Media Specialists in May, 1992. These guidelines are based on interpretation and understanding of current copyright law as applied to education and implemented in school districts in the United…

  15. Insecticidal control of Asian citrus psyllid and Asian citrus leafminer on Hamlin oranges, 2003

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The insecticide trial was initiated to determine the efficacy of various pesticide products for control of Asian citrus pysllid (ACP) and Asian citrus leafminer (CLM) under Florida field conditions. The trial was conducted during the rainy season (cumulative rainfall = 15.6 inches) in a commercial ...

  16. The Asian citrus psyllid and citrus greening - a closer look at the vector

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Homoptera: Psyllidae), was first found in Florida during June 1998 and is now widespread throughout much of the state. This invasive psyllid vectors the bacterium responsible for huanglongbing (HLB) (greening disease), a serious citrus disease. HL...

  17. Impacts of horticultural mineral oils and two insecticide practices on population fluctuation of Diaphorina citri and spread of Huanglongbing in a citrus orchard in Sarawak.

    PubMed

    Leong, Stephen Chan Teck; Abang, Fatimah; Beattie, Andrew; Kueh, Roland Jui Heng; Wong, Sing King

    2012-01-01

    Aspects of the incidence and spread of the citrus disease huanglongbing (HLB) in relation to the vector Diaphorina citri population fluctuation were studied from January 1999 to December 2001 seasons in a 0.8 ha citrus orchard at Jemukan (1° 33'N, 110° 41'E), Southwest Sarawak in Malaysia. In relation to insecticide and horticultural mineral oils (HMOs) use, levels of HLB infection rose quite rapidly over the next 3 years in the unsprayed control and less rapidly in the other treatments such as imidacloprid, nC24HMO, and triazophos/cypermethrin/chlorpyrifos. Levels of HLB as determined by Polymerase Chain Reaction (PCR) were 42.2%, 9.4%, 11.4%, and 22.7%, respectively. The effects of nC(24)HMO and conventional pesticides on the citrus psyllid population and parasitoids in citrus orchard were also determined. PMID:22629178

  18. Impacts of Horticultural Mineral Oils and Two Insecticide Practices on Population Fluctuation of Diaphorina citri and Spread of Huanglongbing in a Citrus Orchard in Sarawak

    PubMed Central

    Leong, Stephen Chan Teck; Abang, Fatimah; Beattie, Andrew; Kueh, Roland Jui Heng; Wong, Sing King

    2012-01-01

    Aspects of the incidence and spread of the citrus disease huanglongbing (HLB) in relation to the vector Diaphorina citri population fluctuation were studied from January 1999 to December 2001 seasons in a 0.8?ha citrus orchard at Jemukan (1° 33?N, 110° 41?E), Southwest Sarawak in Malaysia. In relation to insecticide and horticultural mineral oils (HMOs) use, levels of HLB infection rose quite rapidly over the next 3 years in the unsprayed control and less rapidly in the other treatments such as imidacloprid, nC24HMO, and triazophos/cypermethrin/chlorpyrifos. Levels of HLB as determined by Polymerase Chain Reaction (PCR) were 42.2%, 9.4%, 11.4%, and 22.7%, respectively. The effects of nC24HMO and conventional pesticides on the citrus psyllid population and parasitoids in citrus orchard were also determined. PMID:22629178

  19. Molecular characterization of Wolbachia strains associated with the invasive Asian citrus psyllid Diaphorina citri in Brazil.

    PubMed

    Guidolin, A S; Cônsoli, F L

    2013-02-01

    Wolbachia is a symbiont intensively studied due to its ability to interfere with their host's reproduction, and it has been recently proposed as an alternative tool to control insect pests or vectors of diseases. The Asian citrus psyllid Diaphorina citri is an important pest of citrus since it vectors the bacterium that causes the "Huanglongbing" disease in citrus. The frequency and diversity of Wolbachia associated with D. citri is unknown, limiting the utilization of Wolbachia as an alternative strategy for insect management. Thus, we aimed to determine the natural rate of infection, to characterize the Wolbachia strains associated with this psyllid by "multilocus sequencing typing" (MLST) and wsp analysis, and to verify the association of the symbiont to particular genotypes of the host. Analysis indicated Wolbachia infects 100 % of all specimens tested from all 15 sampled populations. MLST revealed the occurrence of five new sequence types (STs) of Wolbachia, while analysis based on the wsp sequences indicated only four different types of Wolbachia. ST-173 was predominant, while the remaining STs were population specific. Analysis of the host-symbiont relationship did not reveal any particular association of Wolbachia and haplotypes or a decrease in nucleotide diversity of D. citri in populations in which more than one ST was recorded. The consequences of the diversity of STs reported are still unknown, but the fact that Wolbachia infection is fixed and that there is one ST with a broad distribution highlights the use of this symbiont as an alternative strategy to control D. citri. PMID:23269454

  20. In vitro system for studying interactions between Citrus exocortis viroid and Gynura aurantiaca (Blume) DC. metabolism and growing conditions

    Microsoft Academic Search

    Silvija ?erni; Mirna ?urkovi?-Perica; Gordana Rusak; Dijana Škori?

    2011-01-01

    Citrus exocortis viroid (CEVd) is an economically important plant pathogen, which infects a broad range of hosts. In order to investigate complex interactions among viroid, host-growing conditions, and plant secondary metabolism, we setup an in vitro system for the cultivation of CEVd-infected and viroid-free Gynura aurantiaca (Blume) DC. shoots. Both basal Murashige and Skoog (MS) medium and MS medium supplemented

  1. In vitro system for studying interactions between Citrus exocortis viroid and Gynura aurantiaca (Blume) DC. metabolism and growing conditions

    Microsoft Academic Search

    Silvija ?erni; Mirna ?urkovi?-Perica; Gordana Rusak; Dijana Škori?

    2012-01-01

    Citrus exocortis viroid (CEVd) is an economically important plant pathogen, which infects a broad range of hosts. In order to investigate complex interactions among viroid, host-growing conditions, and plant secondary metabolism, we setup an in vitro system for the cultivation of CEVd-infected and viroid-free Gynura aurantiaca (Blume) DC. shoots. Both basal Murashige and Skoog (MS) medium and MS medium supplemented

  2. Site Plan & Site Section of Citrus Landscape (Showing Relationship ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Site Plan & Site Section of Citrus Landscape (Showing Relationship of Groves & Irrigation System to Grove Canal) - Arlington Heights Citrus Landscape, Southwestern portion of city of Riverside, Riverside, Riverside County, CA

  3. Effective disinfection of rough rice using infrared radiation heating.

    PubMed

    Wang, Bei; Khir, Ragab; Pan, Zhongli; El-Mashad, Hamed; Atungulu, Griffiths G; Ma, Haile; McHugh, Tara H; Qu, Wenjuan; Wu, Bengang

    2014-09-01

    The objective of this study was to investigate the effect of infrared (IR) heating and tempering treatments on disinfection of Aspergillus flavus in freshly harvested rough rice and storage rice. Rice samples with initial moisture contents (IMCs) of 14.1 to 27.0% (wet basis) were infected with A. flavus spores before the tests. The infected samples were heated by IR radiation to 60°C in less than 1 min, and then samples were tempered at 60°C for 5, 10, 20, 30, 60, or 120 min. High heating rates and corresponding high levels of moisture removal were achieved using IR heating. The highest total moisture removal was 5.3% for the fresh rice with an IMC of 27.0% after IR heating and then 120 min of tempering. IR heating followed by tempering for 120 min resulted in 2.5- and 8.3-log reductions of A. flavus spores in rough rice with the lowest and highest IMCs, respectively. To study the effect on disinfection of rewetting dried storage rice, the surface of the dry rice was rewetted to achieve IMCs of 14.7 to 19.4% (wet basis). The rewetting process for the dry rice had a significant effect on disinfection. IR heating followed by tempering for 60 min resulted in 7.2-log reductions in A. flavus on rewetted rough rice. The log-linear plus tail model was applied to estimate the tempering time needed to achieve a 5-log reduction of A. flavus in rice of different IMCs. At least 30 and 20 min of tempering were needed for fresh rice and rewetted rice, respectively, with the highest IMCs. The recommended conditions of simultaneous disinfection and drying for fresh rice was IR heating to 60°C followed by tempering for 120 min and natural cooling, resulting in a final MC of 16.5 to 22.0%, depending on the IMC. For the rewetted dry rice with an IMC of 19.4%, the recommended condition for disinfection and drying involved only 20 min of tempering. The final MC of the sample was 13.8%, which is a safe MC for storage rice. PMID:25198845

  4. Evaluation of parameters affecting Agrobacterium -mediated transformation of citrus

    Microsoft Academic Search

    M. Dutt; J. W. Grosser

    2009-01-01

    An improved protocol for genetic transformation of juvenile explants of Carrizo (Citrus sinensis Osb. × Poncirus trifoliata L. Raf.), Duncan (Citrus paradisi Macf.), Hamlin (Citrus sinensis (L.) Osbeck) and Mexican Lime (Citrus aurantifolia Swingle) cultivars using a vector containing a bifunctional egfp-nptII fusion gene is described. Several parameters were investigated to optimize genetic transformation of these four cultivars.\\u000a It was determined that

  5. Studies on the development of functional powder from citrus peel

    Microsoft Academic Search

    H. J. Kang; S. P. Chawla; C. Jo; J. H. Kwon; M. W. Byun

    2006-01-01

    The suitability of citrus peels, generated as a by-product of the juice industry, as a source of antioxidants was investigated. Citrus peel powder was prepared by lyophilizing 70% ethanol extract from citrus peels. Extraction was carried out at room temperature (20°C) for 72h. The extract was subjected to gamma-irradiation treatment (20kGy). The aqueous solutions of citrus peel powder were examined

  6. Synergism between southern rice black-streaked dwarf virus and rice ragged stunt virus enhances their insect vector acquisition.

    PubMed

    Li, Shu; Wang, Han; Zhou, Guohui

    2014-07-01

    Southern rice black-streaked dwarf virus (SRBSDV), a tentative species in the genus Fijivirus, family Reoviridae, is a novel rice virus transmitted by the white-backed planthopper (Sogatella furcifera). Since its discovery in 2001, SRBSDV has spread rapidly throughout eastern and southeastern Asia and caused large rice losses in China and Vietnam. Rice ragged stunt virus (RRSV) (genus Oryzavirus, family Reoviridae) is a common rice virus vectored by the brown planthopper (Nilaparvata lugens). RRSV is also widely distributed in eastern and southeastern Asia but has not previously caused serious problems in China owing to its low incidence. With SRBSDV's spread, however, RRSV has become increasingly common in China, and is frequently found in co-infection with SRBSDV. In this study, we show that SRBSDV and RRSV interact synergistically, the first example of synergism between plant viruses in the family Reoviridae. Rice plants co-infected with both viruses displayed enhanced stunting, earlier symptoms, and higher virus titers compared with singly infected plants. Furthermore, white-backed and brown planthoppers acquired SRBSDV and RRSV, respectively, from co-infected plants at higher rates. We propose that increased RRSV incidence in Chinese fields is partly due to synergism between SRBSDV and RRSV. PMID:24915431

  7. Screening antimicrobial peptides in-vitro for use in developing transgenic citrus resistant to huanglongbing and citrus canker

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB, associated with Candidatus Liberibacter sp.) and Asiatic citrus canker (ACC, causal organism Xanthomonas citri subsp. citri (XCC)) are bacterial diseases that seriously threaten sustainability of the Florida citrus industry. Sweet orange and grapefruit are highly susceptible to A...

  8. Cooked rice texture and rice flour pasting properties; impacted by rice temperature during milling.

    PubMed

    Saleh, Mohammed; Meullenet, Jean-Francois

    2015-03-01

    Rice milling plays a key factor in determining rice quality and value. Therefore accurate quality assessments are critical to the rice industry. This study was undertaken to assess the effect of exposing rice to elevated temperatures during milling, on cooked rice texture and rice flour pasting properties. Two long (Cybonnett and Francis) and one medium (Jupiter) rice (oryzae sativa L.) cultivars were milled using McGill laboratory mill for 30 and 40 s after warmed up the mill before milling. Four different milling temperatures per milling duration were achieved. Cooked rice texture properties were assessed using a uniaxial compression test and rice flour pasting properties measured using a TA-2000 rheometer. Results of this study showed that exposure of rice to high temperatures during milling significantly decreased cooked rice firmness. An increase in milled rice temperature after milling from 10.0 to 13.3 °C resulted in a 5.4 and 8.1 N decrease in cooked rice firmness. Although not always significant, the increase in milled rice temperature during milling resulted in an increase in cooked rice stickiness. The increase in milling temperature also showed significant increase in rice flour pasting properties. Changes in rice functional characteristics were attributed to the changes occurring to rice chemical constituents due to temperature exposure as indicated by the increase in rice protein hydrophobicity. Proteins are known to affect rice starch water holding capacity and other starch gelatinization properties. PMID:25745230

  9. Characterizing the citrus variety Carrizo genome through 454 shotgun sequencing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus production is of global importance both in economic impact and significance to nutrition. The number of natural citrus species appears extremely limited. The genome size is small (haploid approximately 367 Mb), arranged on 18 chromosomes. The citrus variety Carrizo, generated by a ‘Washingt...

  10. Intercropping of citrus and guava trees for management of Huanglongbing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent studies conducted in Viet Nam by Vietnamese, Japanese and Australian scientists indicate that interplanting citrus with guava negated infestations of Asian citrus psyllid and consequently huanglongbing, a serious disease caused by a bacterium vectored by the psyllid. Young citrus interplanted...

  11. Current California Drought: Impact on Citrus Trees and Potential Mitigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    California is in another cycle of extended drought. The article reviews and discusses likely impact of the current drought on citrus growers and potential mitigation techniques. Citrus physiological responses to water stress is briefly reviewed. The direct impact of drought on citrus is reduced frui...

  12. SCREENING CITRUS GERMPLASM FOR RESISTANCE TO XANTHOMONAS AXONOPODIS PV. CITRI

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Numerous studies have been conducted to identify sources of resistance to Xanthomonas axonopodis pv. citri (Xac) among citrus and citrus relatives (Gottwald et al., 2002 and references therein). Kumquats (Fortunella sp.) and Calamondins (Citrus mitis) have shown to be highly resistant and mandarins...

  13. Automating the assessment of citrus canker symptoms with image analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (CC, caused by Xanthomonas citri) is a serious disease of citrus in Florida and other citrus-growing regions. Severity of symptoms can be estimated by visual rating, but there is inter- and intra-rater variation. Automated image analysis (IA) may offer a way of reducing some of ...

  14. Current Situation of Citrus Huanglongbing in Guangdong, P. R. China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Guangdong Province is an important citrus production region in China. Citrus Huanglongbing (HLB, yellow shoot disease) was observed in Guangdong probably in the late 1800’s and the disease was first studied there. Since the 1990’s, citrus production in Guangdong has gradually shifted from the coasta...

  15. Cytokinin activity in Citrus seedlings colonized by mycorrhizal fungi

    E-print Network

    Paris-Sud XI, Université de

    Cytokinin activity in Citrus seedlings colonized by mycorrhizal fungi R.K. Dixon* School of cytokinins in leaves of Citrus jambhiri Lush. seedlings inoculated with vesicular-arbuscular mycorrhizal seedlings were non- mycorrhizal. Inoculation of Citrus seed- lings with vesicular-arbuscular mycorrhi- zal

  16. POPULATION ECOLOGY Phenology of Asian Citrus Psyllid (Hemiptera: Liviidae) and

    E-print Network

    Hoddle, Mark S.

    POPULATION ECOLOGY Phenology of Asian Citrus Psyllid (Hemiptera: Liviidae) and Associated Parasitoids on Two Species of Citrus, Kinnow Mandarin and Sweet Orange, in Punjab Pakistan SHOUKET ZAMAN KHAN1156 (2014); DOI: http://dx.doi.org/10.1603/EN14093 ABSTRACT The population phenology of Asian citrus

  17. Endosymbiotic microbiota of Asian Citrus Psyllid (Diaphorina citri)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The causes of huanglongbing may be induced by more than one microbial agent. Thus, we examined the microbial community in the Asian citrus psyllid (AsCP) (Diaphorina citri, Hemiptera: Psyllidae). Citrus greening is one of the most severe diseases of citrus in Asia and Africa and is caused by an uncu...

  18. Cryopreservation of citrus for long-term conservation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    More than 850 varieties of Citrus, Fortunella, and Citrus-related species are maintained within the USDA-ARS National Plant Germplasm System and the University of California Citrus Variety Collection. These genetic resources are held within duplicated field, screenhouse, and greenhouse collections. ...

  19. DIE REPRSENTIERUNG DES CITRUS-POLLENS IN ITALIENISCHEN ORANGENHONIGEN

    E-print Network

    Paris-Sud XI, Université de

    DIE REPR�SENTIERUNG DES CITRUS-POLLENS IN ITALIENISCHEN ORANGENHONIGEN L'abondance relative du pollen de Citrus dans les miels d'oranger italiens G. VORWOHL Universität Hohenheim (LH) Landesanstalt für Bienenkunde SUMMARY THE REPRESENTATION OF CITRUS POLLEN IN ITALIAN ORANGE HONEYS By means of 61

  20. CITRUS INDUSTRY October 2011 lorida has the second largest

    E-print Network

    Watson, Craig A.

    CITRUS INDUSTRY · October 2011 F lorida has the second largest orange industry in the world after and now, citrus greening disease, also known as huanglongbing (HLB) or yellow shoot disease in Chinese. There are many parallels and inter- actions between the citrus industries of Florida and Brazil, and the short

  1. Converting citrus waste to ethanol and other co-products

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conversion of citrus processing waste (CPW) generated during juice production into value added co-products is an important aspect of the juice industry as it offers a solution to waste disposal issues. Currently the practice of drying citrus waste to produce citrus pulp pellets (CPP) for use as catt...

  2. 21 CFR 74.302 - Citrus Red No. 2.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...restrictions. (1) Citrus Red No. 2 shall be used only for...Oranges colored with Citrus Red No. 2 shall bear not more than...basis of the weight of the whole fruit. (d) Labeling. The...Certification. All batches of Citrus Red No. 2 shall be certified...

  3. 21 CFR 74.302 - Citrus Red No. 2.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...restrictions. (1) Citrus Red No. 2 shall be used only for...Oranges colored with Citrus Red No. 2 shall bear not more than...basis of the weight of the whole fruit. (d) Labeling. The...Certification. All batches of Citrus Red No. 2 shall be certified...

  4. 21 CFR 74.302 - Citrus Red No. 2.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...restrictions. (1) Citrus Red No. 2 shall be used only for...Oranges colored with Citrus Red No. 2 shall bear not more than...basis of the weight of the whole fruit. (d) Labeling. The...Certification. All batches of Citrus Red No. 2 shall be certified...

  5. 21 CFR 74.302 - Citrus Red No. 2.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...restrictions. (1) Citrus Red No. 2 shall be used only for...Oranges colored with Citrus Red No. 2 shall bear not more than...basis of the weight of the whole fruit. (d) Labeling. The...Certification. All batches of Citrus Red No. 2 shall be certified...

  6. 21 CFR 74.302 - Citrus Red No. 2.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...restrictions. (1) Citrus Red No. 2 shall be used only for...Oranges colored with Citrus Red No. 2 shall bear not more than...basis of the weight of the whole fruit. (d) Labeling. The...Certification. All batches of Citrus Red No. 2 shall be certified...

  7. Molecular analysis of citrus rust (Phyllocoptruta oleivora) populations in Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phyllocoptruta olevoria (Acari: Eriophyidae) or the citrus rust mite (CRM) is one of the most economically important mite pests of citrus worldwide. CRM originated from Asia, however it is found in most citrus producing areas, such as, Brazil, Morocco and the United States. Though CRM is a major pes...

  8. Rice yellow mottle virus is transmitted by cows, donkeys, and grass rats in irrigated rice crops

    Microsoft Academic Search

    Soungalo Sarra; Dick Peters

    2003-01-01

    Rice yellow mottle virus (RYMV), endemic in Africa, is believed to be spread by chrysomelid beetles, although the infections in a field often cannot be explained by the prevailing number of beetles. We show that the grass rat Arvicanthis niloticus, domestic cows (Bos spp.), and donkeys (Asinus spp.) are potent and efficient transmitters of RYMV. Spread of RYMV by rats

  9. Incidence of invasive Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae) and its introduced parasitoid Tamarixia radiata (Hymenoptera: Eulophidae) in Florida citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae) vectors the bacterium Candidatus Liberibacter asiaticus, one of the causal organisms of Huanglongbing or citrus greening, a devastating disease of citrus. A eulophid parasitoid, Tamarixia radiata Waterson, was imported ...

  10. Electron microscopic investigations and indexing studies of psorosis and citrus ringspot virus of citrus / by Margaret Atchison Barkley

    E-print Network

    Barkley, Margaret Atchison

    1979-01-01

    ELECTRON MICROSCOPIC INVESTIGATIONS AND INDEXING STUDIES OF PSOROSIS AND CITRUS RINGSPOT VIRUS OF CITRUS A Thesis by MARGARET ATCHISON BARKLEY Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE December 1979 Major Subject: Horticulture ELECTRON MICROSCOPIC INVESTIGATIONS AND INDEXING STUDIES OF PSOROSIS AND CITRUS RINGSPOT VIRUS OF CITRUS A Thesis by MARGARET ATCHISON BARKLEY Approved as to style and content...

  11. Red Yeast Rice: An Introduction

    MedlinePLUS

    ... links Read our disclaimer about external links Menu Red Yeast Rice: An Introduction On this page: Key ... will help ensure coordinated and safe care. About Red Yeast Rice Red yeast rice is made by ...

  12. Does citrus leaf miner impair hydraulics and fitness of citrus host plants?

    PubMed

    Raimondo, Fabio; Trifilò, Patrizia; Gullo, Maria A Lo

    2013-12-01

    Gas exchange and hydraulic features were measured in leaves of three different Citrus species (Citrus aurantium L., Citrus limon L., Citrus ?×? paradisii Macfad) infested by Phyllocnistis citrella Staiton, with the aim to quantify the impact of this pest on leaf hydraulics and, ultimately, on plant fitness. Infested leaves were characterized by the presence on the leaf blade of typical snake-shaped mines and, in some cases, of a crumpled leaf blade. Light microscopy showed that leaf crumpling was induced by damage to the cuticular layer. In all three Citrus species examined: (a) the degree of infestation did not exceed 10% of the total surface area of infested plants; (b) control and infested leaves showed similar values of minimum diurnal leaf water potential, leaf hydraulic conductance and functional vein density; and (c) maximum diurnal values of stomatal conductance to water vapour, transpiration rate and photosynthetic rate (An) were similar in both control leaves and the green areas of infested leaves. A strong reduction of An was recorded only in mined leaf areas. Our data suggest that infestation with P. citrella does not cause conspicuous plant productivity reductions in young Citrus plants, at least not in the three Citrus species studied here. PMID:24319027

  13. Regeneration and characterization of somatic hybrid plants of Citrus sinensis (sweet orange) and Citrus micrantha , a progenitor species of lime

    Microsoft Academic Search

    Iqrar A. Khan; Jude W. Grosser

    2004-01-01

    Most commercial citrus fruit species and cultivars are inter- and intra-specific hybrids. Conventional hybridization in citrus is largely handicapped by apomixis and long juvenility. As an alternative, somatic hybridization via protoplast fusion has been employed to create novel citrus germplasm. Witches' broom disease of lime (WBDL) emerged in Oman during the 1970s, which has been spreading to the neighboring countries.

  14. PROTEOMIC AND GENETIC APPROACHES TO IDENTIFYING DEFENSE-RELATED PROTEINS IN RICE CHALLENGED WITH THE FUNGAL PATHOGEN RHIZOCTONIA SOLANI

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheath blight, caused by the fungus Rhizoctonia solani, is a major disease of rice worldwide, but little is known about the host response to infection. The objective of this study was to identify proteins and DNA markers in resistant and susceptible rice associated with response to infection by R. s...

  15. Rice consumption in China

    E-print Network

    Lan, Jin

    1989-01-01

    undertaken to achieve the purpose can be summarized as follows: (a) to provide a description of China, 's rice industry, focusing on the evolution of production, trends in consumption, the structure of the marketing and distribution systems..., and the nature of government policies. (b) to identify important variables that may explain China's rice consumption. The description of China. 's rice industry will serve as background for the main objective of this study which is to develop quantitative...

  16. Mycotoxins in rice

    Microsoft Academic Search

    Kenji Tanaka; Yuki Sago; Yazhi Zheng; Hiroyuki Nakagawa; Masayo Kushiro

    2007-01-01

    Mycotoxin contamination in rice is usually lower as in wheat or corn. However, there are some reports that rice has been contaminated with mycotoxins such as aflatoxin B1, B2, G1, G2 (AFS), citrinin, deoxynivalenol (DON), fumonisin B1, B2, B3 (FMS), fusarenon-X (Fus.-X), nivalenol (NIV), ochratoxin A (OTA), sterigmatocystin (STE), and zearalenone. Rice in Japan is preserved in warehouses where moisture

  17. RNAi suppression of rice endogenous storage proteins enhances the production of rice-based Botulinum neutrotoxin type A vaccine.

    PubMed

    Yuki, Yoshikazu; Mejima, Mio; Kurokawa, Shiho; Hiroiwa, Tomoko; Kong, Il Gyu; Kuroda, Masaharu; Takahashi, Yoko; Nochi, Tomonori; Tokuhara, Daisuke; Kohda, Tomoko; Kozaki, Shunji; Kiyono, Hiroshi

    2012-06-13

    Mucosal vaccines based on rice (MucoRice) offer a highly practical and cost-effective strategy for vaccinating large populations against mucosal infections. However, the limitation of low expression and yield of vaccine antigens with high molecular weight remains to be overcome. Here, we introduced RNAi technology to advance the MucoRice system by co-introducing antisense sequences specific for genes encoding endogenous rice storage proteins to minimize storage protein production and allow more space for the accumulation of vaccine antigen in rice seed. When we used RNAi suppression of a combination of major rice endogenous storage proteins, 13 kDa prolamin and glutelin A in a T-DNA vector, we could highly express a vaccine comprising the 45 kDa C-terminal half of the heavy chain of botulinum type A neurotoxin (BoHc), at an average of 100 ?g per seed (MucoRice-BoHc). The MucoRice-Hc was water soluble, and was expressed in the cytoplasm but not in protein body I or II of rice seeds. Thus, our adaptation of the RNAi system improved the yield of a vaccine antigen with a high molecular weight. When the mucosal immunogenicity of the purified MucoRice-BoHc was examined, the vaccine induced protective immunity against a challenge with botulinum type A neurotoxin in mice. These findings demonstrate the efficiency and utility of the advanced MucoRice system as an innovative vaccine production system for generating highly immunogenic mucosal vaccines of high-molecular-weight antigens. PMID:22554467

  18. Microbial production of pectin from citrus peel.

    PubMed

    Sakai, T; Okushima, M

    1980-04-01

    A new method for the production of pectin from citrus peel was developed. For this purpose, a microorganism which produces a protopectin-solubilizing enzyme was isolated and identified as a variety of Trichosporon penicillatum. The most suitable conditions for the pectin production were determined as follows. Citrus (Citrus unshiu) peel was suspended in water (1:2, wt/vol), the organism was added, and fermentation proceeded over 15 to 20 h at 30 degrees C. During the fermentation, the pectin in the peel was extracted almost completely without macerating the peel. By this method, 20 to 25 g of pectin was obtained per kg of peel. The pectin obtained was special in that it contained neutral sugar at high levels, which was determined to have a molecular weight suitable for practical applications. PMID:16345556

  19. rice boulevard Tennis Stadium

    E-print Network

    Richards-Kortum, Rebecca

    rice boulevard Jake Hess Tennis Stadium Reckling Park Tennis Courts Practice Field Intramural Field Hess Tennis Stadium, Jake ............34 Holloway Field .................................35 Wendel D

  20. Relationship between gene responses and symptoms induced by Rice grassy stunt virus

    PubMed Central

    Satoh, Kouji; Yoneyama, Kaori; Kondoh, Hiroaki; Shimizu, Takumi; Sasaya, Takahide; Choi, Il-Ryong; Yoneyama, Koichi; Omura, Toshihiro; Kikuchi, Shoshi

    2013-01-01

    Rice grassy stunt virus (RGSV) is a serious threat to rice production in Southeast Asia. RGSV is a member of the genus Tenuivirus, and it induces leaf yellowing, stunting, and excess tillering on rice plants. Here we examined gene responses of rice to RGSV infection to gain insight into the gene responses which might be associated with the disease symptoms. The results indicated that (1) many genes related to cell wall synthesis and chlorophyll synthesis were predominantly suppressed by RGSV infection; (2) RGSV infection induced genes associated with tillering process; (3) RGSV activated genes involved in inactivation of gibberellic acid and indole-3-acetic acid; and (4) the genes for strigolactone signaling were suppressed by RGSV. These results suggest that these gene responses to RGSV infection account for the excess tillering specific to RGSV infection as well as other symptoms by RGSV, such as stunting and leaf chlorosis. PMID:24151491

  1. University of Florida Citrus Research and Education Center

    NSDL National Science Digital Library

    Oranges and other citrus plants have been grown in Florida for well over a century, and there has always been a vital relationship between the universities in the state and the citrus industry. The University of Florida Citrus Research and Education Center (CREC) helps foster these valuable relationships, and they have a facility in Lake Alfred, Florida that includes 600 acres of groves, greenhouses, a fresh fruit packinghouse, and more than 40 laboratories. On their website, visitors can learn about their research into hurricane recovery, advanced citrus production, and plant cell physiology in the "Research" section. Over in the "Extension" area, visitors can learn about the diseases the affect citrus crops, read their free "Citrus Pest Management Guide", and also learn about various pesticides. The site also includes links for the media, along with their in-house "Citrus Leaves" newsletter.

  2. Horsfall-Barratt recalibration and replicated severity estimates of citrus canker

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker is a serious disease of citrus in tropical and subtropical citrus growing regions. Accurate and precise assessment of citrus canker and other plant pathogens is needed to obtain good quality data. Citrus canker assessment data were used to ascertain some of the mechanics of the Horsfal...

  3. Biogenic emissions from Citrus species in California

    NASA Astrophysics Data System (ADS)

    Fares, Silvano; Gentner, Drew R.; Park, Jeong-Hoo; Ormeno, Elena; Karlik, John; Goldstein, Allen H.

    2011-09-01

    Biogenic Volatile Organic Compounds (BVOC) emitted from plants are the dominant source of reduced carbon chemicals to the atmosphere and are important precursors to the photochemical production of ozone and secondary organic aerosols. Considering the extensive land used for agriculture, cultivated Citrus plantations may play an important role in the chemistry of the atmosphere especially in regions such as the Central Valley of California. Moreover, the BVOC emissions from Citrus species have not been characterized in detail and more species-specific inputs for regional models of BVOC emissions are needed. In this study, we measured the physiological parameters and emissions of the most relevant BVOC (oxygenated compounds, monoterpenes, and sesquiterpenes) for four predominant Citrus species planted in California ( Citrus sinensis var. 'Parent Navel', Citrus limon var. 'Meyer', Citrus reticulata var. 'W. Murcott' and 'Clementine'). We used two analytical techniques to measure a full range of BVOC emitted: Proton Transfer Reaction Mass Spectrometry (PTR-MS) and gas chromatography with mass spectrometry. Methanol, followed by acetone and acetaldehyde, were the dominant BVOC emitted from lemon and mandarin trees (basal emission rates up to 300 ng(C) g(DW) -1 h -1), while oxygenated monoterpenes, monoterpenes, and sesquiterpenes were the main BVOC emitted from orange trees (basal emission rates up to = 2500 ng(C) g(DW) -1 h -1). Light and temperature-dependent algorithms were better predictors of methanol, acetaldehyde, acetone, isoprene and monoterpenes for all the Citrus species. Whereas, temperature-dependent algorithms were better predictors of oxygenated monoterpenes, and sesquiterpenes. We observed that flowering increased emissions from orange trees by an order of magnitude with the bulk of BVOC emissions being comprised of monoterpenes, sesquiterpenes, and oxygenated monoterpenes. Chemical speciation of BVOC emissions show that the various classes of terpene emissions among all Citrus species are dominated by ocimenes, ?-caryophyllene, and linalool, respectively. In addition to utilizing our reported emission factors in BVOC emission models, we recommend that future BVOC emission models consider additional emissions from flowering and harvest, which occur seasonally and may have a significant impact on regional atmospheric chemistry.

  4. 78 FR 41259 - Importation of Fresh Citrus Fruit From Uruguay, Including Citrus

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-10

    ...must be physically present in an exporting country or region to facilitate...particularly in the near term, given the advantages of maintaining and expanding its...the packinghouse is in use for exporting citrus fruit to the...

  5. Rice Ratooning Management Practices for Higher Yields

    Microsoft Academic Search

    A. B. Santos; N. K. Fageria; A. S. Prabhu

    2003-01-01

    Rice is one of the world's most important cereal crops and rice ratooning is one of the potential technologies to increase rice production. Based on land and water management, rice ecosystem is mainly divided into lowland, upland and deep water or floating rice. Rice ratooning is mainly practiced on lowland rice ecosystem. Ratooning provides higher resource use efficiency per unit

  6. EXIT INTERVIEW SUMMARY FORM Life after Rice...

    E-print Network

    Richards-Kortum, Rebecca

    1 EXIT INTERVIEW SUMMARY FORM Life after Rice... Rice ID: _____________________ * Medical benefits - Your Rice medical benefits will end on: __________________________ * Vesting in the 401(a) Rice. * Rice retiree - If you qualify as a Rice retiree, in accordance with the Rice University Human Resources

  7. 76 FR 78228 - Notice of Request for Extension of Approval of an Information Collection; Citrus Greening and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-16

    ...Extension of Approval of an Information Collection; Citrus Greening and Asian Citrus Psyllid; Quarantine and Interstate Movement Regulations...associated with regulations to prevent the spread of citrus greening and its vector, Asian citrus...

  8. Effect of rice hull ash silicon on rice seedling growth

    Microsoft Academic Search

    K. R. Sistani; N. K. Savant; K. C. Reddy

    1997-01-01

    Silicon (Si) promotes healthy development of rice plants. Research has shown that an adequate supply of Si to rice plants improves the plant resistance to abiotic and biotic stresses such as soil aluminum (Al) and manganese (Mn) toxicities and plant pest and diseases. Rice hull, a major by?product of rice milling, contains about 8% Si that can be recycled for

  9. A genetic system for Citrus Tristeza Virus using the non-natural host Nicotiana benthamiana: an update

    PubMed Central

    Ambrós, Silvia; Ruiz-Ruiz, Susana; Peña, Leandro; Moreno, Pedro

    2013-01-01

    In nature Citrus tristeza virus (CTV), genus Closterovirus, infects only the phloem cells of species of Citrus and related genera. Finding that the CTV T36 strain replicated in Nicotiana benthamiana (NB) protoplasts and produced normal virions allowed development of the first genetic system based on protoplast transfection with RNA transcribed from a full-genome cDNA clone, a laborious and uncertain system requiring several months for each experiment. We developed a more efficient system based on agroinfiltration of NB leaves with CTV-T36-based binary plasmids, which caused systemic infection in this non-natural host within a few weeks yielding in the upper leaves enough CTV virions to readily infect citrus by slash inoculation. Stem agroinoculation of citrus and NB plants with oncogenic strains of Agrobacterium tumefaciens carrying a CTV-T36 binary vector with a GUS marker, induced GUS positive galls in both species. However, while most NB tumors were CTV positive and many plants became systemically infected, no coat protein or viral RNA was detected in citrus tumors, even though CTV cDNA was readily detected by PCR in the same galls. This finding suggests (1) strong silencing or CTV RNA processing in transformed cells impairing infection progress, and (2) the need for using NB as an intermediate host in the genetic system. To maintain CTV-T36 in NB or assay other CTV genotypes in this host, we also tried to graft-transmit the virus from infected to healthy NB, or to mechanically inoculate NB leaves with virion extracts. While these trials were mostly unsuccessful on non-treated NB plants, agroinfiltration with silencing suppressors enabled for the first time infecting NB plants by side-grafting and by mechanical inoculation with virions, indicating that previous failure to infect NB was likely due to virus silencing in early infection steps. Using NB as a CTV host provides new possibilities to study virus-host interactions with a simple and reliable system. PMID:23847598

  10. Transgenic strategies to confer resistance against viruses in rice plants

    PubMed Central

    Sasaya, Takahide; Nakazono-Nagaoka, Eiko; Saika, Hiroaki; Aoki, Hideyuki; Hiraguri, Akihiro; Netsu, Osamu; Uehara-Ichiki, Tamaki; Onuki, Masatoshi; Toki, Seichi; Saito, Koji; Yatou, Osamu

    2014-01-01

    Rice (Oryza sativa L.) is cultivated in more than 100 countries and supports nearly half of the world’s population. Developing efficient methods to control rice viruses is thus an urgent necessity because viruses cause serious losses in rice yield. Most rice viruses are transmitted by insect vectors, notably planthoppers and leafhoppers. Viruliferous insect vectors can disperse their viruses over relatively long distances, and eradication of the viruses is very difficult once they become widespread. Exploitation of natural genetic sources of resistance is one of the most effective approaches to protect crops from virus infection; however, only a few naturally occurring rice genes confer resistance against rice viruses. Many investigators are using genetic engineering of rice plants as a potential strategy to control viral diseases. Using viral genes to confer pathogen-derived resistance against crops is a well-established procedure, and the expression of various viral gene products has proved to be effective in preventing or reducing infection by various plant viruses since the 1990s. RNA interference (RNAi), also known as RNA silencing, is one of the most efficient methods to confer resistance against plant viruses on their respective crops. In this article, we review the recent progress, mainly conducted by our research group, in transgenic strategies to confer resistance against tenuiviruses and reoviruses in rice plants. Our findings also illustrate that not all RNAi constructs against viral RNAs are equally effective in preventing virus infection and that it is important to identify the viral “Achilles’ heel” gene to target for RNAi attack when engineering plants. PMID:24454308

  11. Dietary rice bran promotes resistance to Salmonella enterica serovar Typhimurium colonization in mice

    PubMed Central

    2012-01-01

    Background Dietary rice bran consists of many bioactive components with disease fighting properties; including the capacity to modulate the gut microbiota. Studies point to the important roles of the gut microbiota and the mucosal epithelium in the establishment of protection against enteric pathogens, such as Salmonella. The ability of rice bran to reduce the susceptibility of mice to a Salmonella infection has not been previously investigated. Therefore, we hypothesized that the incorporation of rice bran into the diet would inhibit the colonization of Salmonella in mice through the induction of protective mucosal responses. Results Mice were fed diets containing 0%, 10% and 20% rice bran for one week prior to being orally infected with Salmonella enterica serovar Typhimurium. We found that mice consuming the 10 and 20% rice bran diets exhibited a reduction in Salmonella fecal shedding for up to nine days post-infection as compared to control diet fed animals (p?rice bran fed mice (p?rice bran extracts to reduce Salmonella entry into mouse small intestinal epithelial cells. Conclusions Increasing rice bran consumption represents a novel dietary means for reducing susceptibility to enteric infection with Salmonella and potentially via induction of native Lactobacillus spp. PMID:22583915

  12. Analysis of rice PDR-like ABC transporter genes in sheath blight resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheath blight caused by Rhizoctonia solani is one of the most damaging diseases of rice worldwide. To understand the molecular mechanism of resistance, we identified 450 differentially expressed genes in a resistant rice cultivar Jasmine 85 after R. solani infection with a combination of DNA microar...

  13. Yield and quality responses of citrus (Citrus reticulate) and tea (Podocarpus fleuryi Hickel.) to compound fertilizers.

    PubMed

    Wang, Rui; Shi, Xue-gen; Wei, You-zhang; Yang, Xiao-e; Uoti, Juhani

    2006-09-01

    Experiments were carried out with citrus (Citrus reticulate) and tea (Podocarpus fleuryi Hickel.) to study the effects of compound fertilizers on their yields and quality. In the citrus experiment, application of compound fertilizers increased available P, K and Mg contents in soil but decreased alkali-hydrolyzable N contents in soil and N, P and K contents in leaves. In the tea experiment, application of compound fertilizers increased available P, K and Mg contents in soil and N, P, K and Mg contents in leaves but decreased alkali-hydrolyzable N in soil compared with the urea treatment. Application of compound fertilizers could improve the quality of citrus and tea, increase their yields and enhance their economical profits significantly. Compared with the control, application of compound fertilizers increased citrus yields by 6.31, 12.94 and 17.69 t/ha, and those of tea by 0.51, 0.86 and 1.30 t/ha, respectively. Correspondingly, profits were increased by 21.4% to 61.1% for citrus and by 10.0% to 15.7% for tea. Optimal rates of compound fertilizers were recommended for both crops. PMID:16909469

  14. Induced mutations in rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Induced mutations have a long history in both applied and basic aspects of rice research. During the past fifty years, over 500 rice varieties have been developed worldwide, either directly from induced mutants or as a result of crossing such mutants with other breeding lines. More recently, the gen...

  15. Registration of 'Cybonnet' Rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ‘Cybonnet’ rice is a high-yielding, short-season, long-grain cultivar. It originated form the cross ‘Cypress’//’Newbonnet’/’Katy’ made at the University of Arkansas Rice Research and Extension Center in Stuttgart, AR. Cybonnet is similar in maturity to ‘Kaybonnet’ and ‘Wells’, is a simidwarf culti...

  16. Virus Resistance in Rice

    Microsoft Academic Search

    D. Fargette; A. Ghesquière; L. Albar; J. M. Thresh

    The genus Oryza of the Family Gramineae comprises 18 tropical and subtropical species, of which two species are cultivated as rice: O. sativa and O. glaberrima. Rice provides the staple food of 60% of mankind, and is cultivated in all tropical and subtropical countries. Oryza sativa is thought to have been domesticated in China before 6500 BC, in India between

  17. QTL mapping in rice

    Microsoft Academic Search

    Susan R. McCough; Rebecca W. Doerge

    1995-01-01

    In the past 10 years, interest in applying the tools of molecular genetics to the problem of increasing world rice production has resulted in the generation of two highly saturated, molecular linkage maps of rice, and the localization of numerous genes and quantitative trait loci (QTLs). Primary studies have identified QTLs associated with disease resistance, abiotic stress tolerance and yield

  18. Comparative Transcriptome Analysis of Two Rice Varieties in Response to Rice Stripe Virus and Small Brown Planthoppers during Early Interaction

    PubMed Central

    Zheng, Wenjing; Ma, Li; Zhao, Jiaming; Li, Zhiqiang; Sun, Fuyu; Lu, Xiaochun

    2013-01-01

    Rice stripe, a virus disease, transmitted by a small brown planthopper (SBPH), has greatly reduced production of japonica rice in East Asia, especially in China. Although we have made great progress in mapping resistance genes, little is known about the mechanism of resistance. By de novo transcriptome assembling, we gained sufficient transcript data to analyze changes in gene expression of early interaction in response to SBPH and RSV infection in rice. Respectively 648 and 937 DEGs were detected from the disease-resistant (Liaonong 979) and the susceptible (Fengjin) varieties, most of which were up-regulated. We found 37 genes related to insect resistance, which mainly included genes for jasmonate-induced protein, TIFY protein, lipoxygenase, as well as trypsin inhibitor genes and transcription factor genes. In the interaction process between RSV and rice, 87 genes were thought to be related to RSV resistance; these primarily included 12 peroxidase biosynthesis genes, 12 LRR receptor-like protein kinase genes, 6 genes coding pathogenesis-related proteins, 4 glycine-rich cell wall structural protein genes, 2 xyloglucan hydrolase genes and a cellulose synthase. The results indicate that the rice-pathogen interaction happened both in disease-resistant and susceptible varieties, and some genes related to JA biosynthesis played key roles in the interaction between SBPHs and rice. When rice was infected by RSV a hypersensitive reaction (HR) in the disease-resistant variety was suppressed, which resulted from an increase in peroxidase expression and down-regulation of LRR receptor-like protein kinase and pathogenesis-related proteins, while, the changes of peroxidase biosynthesis, glycine-rich cell wall structural protein, cellulose synthase and xyloglucan endotransglucosylase/hydrolase could lead to the strengthening of physical barriers of rice, which may be an important resistance mechanism to RSV in rice. PMID:24358146

  19. Virus-mediated chemical changes in rice plants impact the relationship between non-vector planthopper Nilaparvata lugens Stål and its egg parasitoid Anagrus nilaparvatae Pang et Wang.

    PubMed

    He, Xiaochan; Xu, Hongxing; Gao, Guanchun; Zhou, Xiaojun; Zheng, Xusong; Sun, Yujian; Yang, Yajun; Tian, Junce; Lu, Zhongxian

    2014-01-01

    In order to clarify the impacts of southern rice black-streaked dwarf virus (SRBSDV) infection on rice plants, rice planthoppers and natural enemies, differences in nutrients and volatile secondary metabolites between infected and healthy rice plants were examined. Furthermore, the impacts of virus-mediated changes in plants on the population growth of non-vector brown planthopper (BPH), Nilaparvata lugens, and the selectivity and parasitic capability of planthopper egg parasitoid Anagrus nilaparvatae were studied. The results showed that rice plants had no significant changes in amino acid and soluble sugar contents after SRBSDV infection, and SRBSDV-infected plants had no significant effect on population growth of non-vector BPH. A. nilaparvatae preferred BPH eggs both in infected and healthy rice plants, and tended to parasitize eggs on infected plants, but it had no significant preference for infected plants or healthy plants. GC-MS analysis showed that tridecylic aldehyde occurred only in rice plants infected with SRBSDV, whereas octanal, undecane, methyl salicylate and hexadecane occurred only in healthy rice plants. However, in tests of behavioral responses to these five volatile substances using a Y-tube olfactometer, A. nilaparvatae did not show obvious selectivity between single volatile substances at different concentrations and liquid paraffin in the control group. The parasitic capability of A. nilaparvatae did not differ between SRBSDV-infected plants and healthy plant seedlings. The results suggested that SRBSDV-infected plants have no significant impacts on the non-vector planthopper and its egg parasitoid, A. nilaparvatae. PMID:25141278

  20. Virus-Mediated Chemical Changes in Rice Plants Impact the Relationship between Non-Vector Planthopper Nilaparvata lugens Stål and Its Egg Parasitoid Anagrus nilaparvatae Pang et Wang

    PubMed Central

    Gao, Guanchun; Zhou, Xiaojun; Zheng, Xusong; Sun, Yujian; Yang, Yajun; Tian, Junce; Lu, Zhongxian

    2014-01-01

    In order to clarify the impacts of southern rice black-streaked dwarf virus (SRBSDV) infection on rice plants, rice planthoppers and natural enemies, differences in nutrients and volatile secondary metabolites between infected and healthy rice plants were examined. Furthermore, the impacts of virus-mediated changes in plants on the population growth of non-vector brown planthopper (BPH), Nilaparvata lugens, and the selectivity and parasitic capability of planthopper egg parasitoid Anagrus nilaparvatae were studied. The results showed that rice plants had no significant changes in amino acid and soluble sugar contents after SRBSDV infection, and SRBSDV-infected plants had no significant effect on population growth of non-vector BPH. A. nilaparvatae preferred BPH eggs both in infected and healthy rice plants, and tended to parasitize eggs on infected plants, but it had no significant preference for infected plants or healthy plants. GC-MS analysis showed that tridecylic aldehyde occurred only in rice plants infected with SRBSDV, whereas octanal, undecane, methyl salicylate and hexadecane occurred only in healthy rice plants. However, in tests of behavioral responses to these five volatile substances using a Y-tube olfactometer, A. nilaparvatae did not show obvious selectivity between single volatile substances at different concentrations and liquid paraffin in the control group. The parasitic capability of A. nilaparvatae did not differ between SRBSDV-infected plants and healthy plant seedlings. The results suggested that SRBSDV-infected plants have no significant impacts on the non-vector planthopper and its egg parasitoid, A. nilaparvatae. PMID:25141278

  1. Rice University GeneralAnnouncements

    E-print Network

    Richards-Kortum, Rebecca

    Rice University GeneralAnnouncements 2001­2002 #12;NOTE: This catalog represents the most accurate without notice. William Marsh Rice University Physical Address: 6100 Main Street, Houston, Texas 77005 Address: http://www.rice.edu 2001­2002 General Announcements online: http://www.ruf.rice

  2. Rice University GeneralAnnouncements

    E-print Network

    Richards-Kortum, Rebecca

    Rice University GeneralAnnouncements 2002­2003 #12;NOTE: This catalog represents the most accurate without notice. William Marsh Rice University Physical Address: 6100 Main Street, Houston, Texas 77005 Address: http://www.rice.edu 2001­2002 General Announcements online: http://www.ruf.rice

  3. Rice University GeneralAnnouncements

    E-print Network

    Richards-Kortum, Rebecca

    Rice University GeneralAnnouncements 2003­2004 #12;NOTE: This catalog represents the most accurate without notice. William Marsh Rice University Physical Address: 6100 Main Street, Houston, Texas 77005 Address: http://www.rice.edu 2003­2004 General Announcements online: http://www.rice.edu/catalog/ Please

  4. RICE AND RED RICE INTERFERENCE: II. RICE RESPONSE TO POPULATION DENSITIES OF THREE RED RICE (ORYZA SATIVA) ECOTYPES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Red rice, which grows taller and produces more tillers than domestic rice and shatters most of its seeds early, is a major weed in many rice-growing areas of the world. Field experiments were conducted at Stuttgart, AR in 1997 and 1998 to evaluate the growth response of the Kaybonnet (KBNT) rice cul...

  5. Bioengineering nitrogen acquisition in rice

    E-print Network

    Britto, Dev T.

    Bioengineering nitrogen acquisition in rice: can novel initiatives in rice genomics and physiology contribute to global food security? Dev T. Britto and Herbert J. Kronzucker* Summary Rice is the most and expansion of arable land have massively increased global rice production, enabling crop scientists

  6. Information: Rice Young Alumni Information

    E-print Network

    Palem, Krishna V.

    Rice Young Alumni Detailed Information: Houston Events 2011-2012 #12; Rice Young Alumni Information Alumni.rice.edu 2 Join the Parliament in HoustonHouston Young Alumni Events This page to this site for more information and visit our Rice Young Alumni Houston Facebook page for special details

  7. Asian Citrus Psyllid, Genetic Basis of Immunity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We used a genomics approach to identify some of the genetic bases of D. citri immunity, identifying in particular genes associated with environmental and biological stresses. Only a few insecticides are being used to manage the Asian citrus psyllid (AsCP), Diaphorina citri (Hemiptera: Psyllidae), to...

  8. Asian citrus psyllid - biology and seasonal ecology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The seasonal ecology of Diaphorina citri was investigated in a non-irrigated citrus grove of mature orange trees beginning January 2005 in east central Florida. No insecticides were applied during the study. Predators including lady beetles, lacewings and syrphid flies were observed during the stud...

  9. Founder lines for improved citrus biotechnology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This article discusses the research needed to develop the RMCE strategy and molecular assays for site-specific recombinases as tools for genome manipulation. Explanation of genetic engineering used to generate transgenic citrus plants to exhibit a novel phenotype, but not to contain the recombinase...

  10. Asian citrus psyllid genome (Diaphorina citri, Hemiptera)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Psyllid genome is a scientific breakthrough in that it opens the psyllid genetic blueprint to investigations of all questions ranging from taxonomic origins to the understanding of developmental biology, to the acquisition and transmission of pathogens. The Asian citrus psyllid, Diaphorina citri...

  11. Assessment of Stubborn Disease Incidence in Citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus stubborn disease, caused by Spiroplasma Citri, has occured in California for more than 90 years, however, detection methods for estimating disease incidence have not been well developed. Two 8 ha plots in Kern Co. CA were established and sampled in July and August, 2006. Different tissues o...

  12. Ecology of the Asian citrus pysllid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Host selection by psyllids in general appears to involve taste rather than olfaction. Adults are often less discriminating than nymphs. A priori, there is good reason to doubt that Asian citrus psyllid (ACP) uses a long-distance sex pheromone or that ACP orients to host plant volatiles over large (m...

  13. Citrus Huanglongbing: The Pathogen and Its Impact

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The article is a detailed review of the present status of huanglongbing (HLB) in the US and Brazil. HLB is known to be the most severe and destructive of all diseases of citrus greatly affecting yield and quality, and leads to tree death. It also has severe regulatory and quarantine implications a...

  14. PHYTOCHEMICAL ANALYSIS OF CITRUS SINENSIS PEEL

    E-print Network

    Pankaja S. Chede; Kiran Nagar; Amravati M. S

    Citrus Sinensis peel was screened for its phytochemical composition. The aqueous as well as the ethanoic extracts of the peel revealed the presence of carbohydrates, alkaloids, tannins, fixed oils and lipids, sugars, proteins, terpenoids, steroids, and amino acids whereas the saponins are present only in the ethanolic extract.

  15. NPDN Citrus Greening Diagnostic and Detection Efforts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The National Plant Diagnostic Network (NPDN) has been involved in detection and diagnosis of many new plant diseases, including citrus greening, huanglongbing (HLB), caused by a fastidious bacterium, Candidatus Liberibacter asiaticus. The pathogen is on the USDA List of Select Agents, which indicat...

  16. Assessment of Stubborn Disease Incidence in Citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus stubborn disease (CSD) has been a problem in California for over 90 years, yet, methods for rapidly detecting its causal agent, Spiroplasma citri, for use in estimating disease incidence have not been optimized. Two 8 ha blocks within two commercial groves were sampled in July and August, 20...

  17. Large scale germplasm screening for identification of novel rice blast resistance sources

    PubMed Central

    Vasudevan, Kumar; Vera Cruz, Casiana M.; Gruissem, Wilhelm; Bhullar, Navreet K.

    2014-01-01

    Rice is a major cereal crop that contributes significantly to global food security. Biotic stresses, including the rice blast fungus, cause severe yield losses that significantly impair rice production worldwide. The rapid genetic evolution of the fungus often overcomes the resistance conferred by major genes after a few years of intensive agricultural use. Therefore, resistance breeding requires continuous efforts of enriching the reservoir of resistance genes/alleles to effectively tackle the disease. Seed banks represent a rich stock of genetic diversity, however, they are still under-explored for identifying novel genes and/or their functional alleles. We conducted a large-scale screen for new rice blast resistance sources in 4246 geographically diverse rice accessions originating from 13 major rice-growing countries. The accessions were selected from a total collection of over 120,000 accessions based on their annotated rice blast resistance information in the International Rice Genebank. A two-step resistance screening protocol was used involving natural infection in a rice uniform blast nursery and subsequent artificial infections with five single rice blast isolates. The nursery-resistant accessions showed varied disease responses when infected with single isolates, suggesting the presence of diverse resistance genes/alleles in this accession collection. In addition, 289 accessions showed broad-spectrum resistance against all five single rice blast isolates. The selected resistant accessions were genotyped for the presence of the Pi2 resistance gene, thereby identifying potential accessions for isolation of allelic variants of this blast resistance gene. Together, the accession collection with broad spectrum and isolate specific blast resistance represent the core material for isolation of previously unknown blast resistance genes and/or their allelic variants that can be deployed in rice breeding programs. PMID:25324853

  18. 7 CFR 301.75-5 - Commercial citrus-producing areas.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 false Commercial citrus-producing areas. 301.75-5...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations § 301.75-5 Commercial citrus-producing areas. (a) The...

  19. 40 CFR 407.30 - Applicability; description of the citrus products subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Applicability; description of the citrus products subcategory. 407.30 ...VEGETABLES PROCESSING POINT SOURCE CATEGORY Citrus Products Subcategory § 407.30 Applicability; description of the citrus products subcategory. The...

  20. 40 CFR 407.30 - Applicability; description of the citrus products subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Applicability; description of the citrus products subcategory. 407.30 ...VEGETABLES PROCESSING POINT SOURCE CATEGORY Citrus Products Subcategory § 407.30 Applicability; description of the citrus products subcategory. The...

  1. 7 CFR 905.114 - Redistricting of citrus districts and reapportionment of grower members.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 false Redistricting of citrus districts and reapportionment of grower...Regulations § 905.114 Redistricting of citrus districts and reapportionment of grower members. Pursuant to § 905.14, the citrus districts and membership allotted...

  2. 40 CFR 407.30 - Applicability; description of the citrus products subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Applicability; description of the citrus products subcategory. 407.30 ...VEGETABLES PROCESSING POINT SOURCE CATEGORY Citrus Products Subcategory § 407.30 Applicability; description of the citrus products subcategory. The...

  3. 7 CFR 905.114 - Redistricting of citrus districts and reapportionment of grower members.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 false Redistricting of citrus districts and reapportionment of grower...Regulations § 905.114 Redistricting of citrus districts and reapportionment of grower members. Pursuant to § 905.14, the citrus districts and membership allotted...

  4. 7 CFR 301.75-17 - Funds for the replacement of certified citrus nursery stock.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...Funds for the replacement of certified citrus nursery stock. 301.75-17 Section...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations...Funds for the replacement of certified citrus nursery stock. Subject to the...

  5. 40 CFR 407.30 - Applicability; description of the citrus products subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Applicability; description of the citrus products subcategory. 407.30 ...VEGETABLES PROCESSING POINT SOURCE CATEGORY Citrus Products Subcategory § 407.30 Applicability; description of the citrus products subcategory. The...

  6. 7 CFR 301.75-5 - Commercial citrus-producing areas.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 false Commercial citrus-producing areas. 301.75-5...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations § 301.75-5 Commercial citrus-producing areas. (a) The...

  7. 7 CFR 301.75-17 - Funds for the replacement of certified citrus nursery stock.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...Funds for the replacement of certified citrus nursery stock. 301.75-17 Section...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations...Funds for the replacement of certified citrus nursery stock. Subject to the...

  8. 7 CFR 319.56-59 - Fresh citrus fruit from Uruguay.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Fresh citrus fruit from Uruguay. 319.56-59 Section...Fruits and Vegetables § 319.56-59 Fresh citrus fruit from Uruguay. Sweet oranges (Citrus sinensis (L.) Osbeck), lemons...

  9. 7 CFR 905.114 - Redistricting of citrus districts and reapportionment of grower members.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 false Redistricting of citrus districts and reapportionment of grower...Regulations § 905.114 Redistricting of citrus districts and reapportionment of grower members. Pursuant to § 905.14, the citrus districts and membership allotted...

  10. 7 CFR 301.75-5 - Commercial citrus-producing areas.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 false Commercial citrus-producing areas. 301.75-5...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations § 301.75-5 Commercial citrus-producing areas. (a) The...

  11. 7 CFR 301.75-17 - Funds for the replacement of certified citrus nursery stock.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...Funds for the replacement of certified citrus nursery stock. 301.75-17 Section...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations...Funds for the replacement of certified citrus nursery stock. Subject to the...

  12. 7 CFR 301.75-17 - Funds for the replacement of certified citrus nursery stock.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...Funds for the replacement of certified citrus nursery stock. 301.75-17 Section...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations...Funds for the replacement of certified citrus nursery stock. Subject to the...

  13. 7 CFR 301.75-17 - Funds for the replacement of certified citrus nursery stock.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...Funds for the replacement of certified citrus nursery stock. 301.75-17 Section...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations...Funds for the replacement of certified citrus nursery stock. Subject to the...

  14. 7 CFR 301.75-5 - Commercial citrus-producing areas.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 false Commercial citrus-producing areas. 301.75-5...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations § 301.75-5 Commercial citrus-producing areas. (a) The...

  15. 78 FR 58992 - Notice of Request for Extension of Approval of an Information Collection; Citrus Canker...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-25

    ...Approval of an Information Collection; Citrus Canker; Interstate Movement of Regulated...quarantined areas to prevent the spread of citrus canker. DATES: We will consider all...regulated nursery stock and fruit from citrus canker quarantined areas, contact...

  16. 40 CFR 407.30 - Applicability; description of the citrus products subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Applicability; description of the citrus products subcategory. 407.30 ...VEGETABLES PROCESSING POINT SOURCE CATEGORY Citrus Products Subcategory § 407.30 Applicability; description of the citrus products subcategory. The...

  17. 7 CFR 301.75-5 - Commercial citrus-producing areas.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 false Commercial citrus-producing areas. 301.75-5...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations § 301.75-5 Commercial citrus-producing areas. (a) The...

  18. Leadership Rice The mission of Leadership Rice is to help Rice University undergraduates from

    E-print Network

    Richards-Kortum, Rebecca

    189 Leadership Rice The mission of Leadership Rice is to help Rice University undergraduates from all disciplines build their leadership capacities to create and manage change ef- fectively. Leadership Rice explores how heart and mind, theory and practice, and ideas and actions come together

  19. Leadership Rice Leadership Rice exists to encourage and equip Rice students to obtain

    E-print Network

    Richards-Kortum, Rebecca

    Leadership Rice Leadership Rice exists to encourage and equip Rice students to obtain leadership roles at Rice and beyond. We provide leadership development opportunities to undergraduates from every ambition for leadership. We seek to accomplish our mission through a blend of curricular and co

  20. POST-HURRICANE ANALYSIS OF CITRUS CANKER II: PREDICTIVE MODEL ESTIMATION OF DISEASE SPREAD AND AREA POTENTIALLY IMPACTED BY VARIOUS ERADICATION PROTOCOLS FOLLOWING CATASTROPHIC WEATHER EVENTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The affect of 2005 Hurricane Wilma on the dissemination of Xanthomonas axonopodis pv. citri (Xac), the cause of Asiatic citrus canker (ACC), and subsequent disease development was examined and predictions for the areas into which Xac was likely to have spread from known sources of infection was deve...

  1. Profiling of the small RNA populations derived from sour orange seedlings cross-protected against seedling yellows strains of Citrus tristeza virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Control of Citrus tristeza virus (CTV) in central California changed in 2009 from removal of all CTV-infected trees to only those which react positive in tests with selective probes for potentially severe CTV strains. Therefore, new strategies for CTV control are needed. Greenhouse tests have show...

  2. A phytoplasma related to Candidatus Phytoplasma asteri is associated with citrus showing Huanglongbing (yellow shoot disease) symptoms in Guangdong, P. R. China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) or yellow shoot disease (ex. greening disease) is highly destructive to citrus production worldwide. Understanding the etiology of HLB is critical for managing the disease. HLB is currently known to be associated with infection by Candidatus Liberibacter asiaticus in China. Howev...

  3. Multi-stage Robust Scheme for Citrus Identification from High Resolution Airborne Images

    E-print Network

    Camps-Valls, Gustavo

    Multi-stage Robust Scheme for Citrus Identification from High Resolution Airborne Images Julia Amor to similar problems and applications. Keywords: Tree identification, citrus, GIS, feature extraction

  4. Cyclic Lipopeptides from Bacillus subtilis ABS–S14 Elicit Defense-Related Gene Expression in Citrus Fruit

    PubMed Central

    Waewthongrak, Waewruedee; Leelasuphakul, Wichitra; McCollum, Greg

    2014-01-01

    Effects of cyclic lipopeptides (CLPs) obtained from Bacillus subtilis ABS-S14 on eliciting defense-related gene transcription and activity of defense-related enzymes; glucanase (GLU), chitinase (CHI), peroxidase (POX) and lipoxygenase (LOX) in Citrus sinensis cv. Valencia fruit were determined. The maximum level of GLU transcripts induced in fruit treated with fengycin was significantly greatest among treatments at 48 h. Surfactin enhanced the LOX and POX transcripts. In parallel, corresponding enzyme activities were correlated with changes in gene expression observed in fruit inoculated with Penicillium digitatum following treatment with individual CLPs. Synergistic effects of fengycin and iturin A, fengycin and surfactin were shown in gene transcript of GLU and CHI, respectively, and surfactin induced POX and LOX gene expression of citrus flavedo without pathogen infection. These results suggest that fengycin and surfactin act as elicitors of defense-related gene expression in “Valencia” fruit following infection. PMID:25329301

  5. Candidatus Liberibacter americanus induces significant reprogramming of the transcriptome of the susceptible citrus genotype

    PubMed Central

    2013-01-01

    Background Citrus huanglongbing (HLB) disease is caused by endogenous, phloem-restricted, Gram negative, uncultured bacteria named Candidatus Liberibacter africanus (CaLaf), Ca. L. asiaticus (CaLas), and Ca. L. americanus (CaLam), depending on the continent where the bacteria were first detected. The Asian citrus psyllid vector, Diaphorina citri, transmits CaLas and CaLam and both Liberibacter species are present in Brazil. Several studies of the transcriptional response of citrus plants manifesting HLB symptoms have been reported, but only for CaLas infection. This study evaluated the transcriptional reprogramming of a susceptible genotype of sweet orange challenged with CaLam, using a customized 385K microarray containing approximately 32,000 unigene transcripts. We analyzed global changes in gene expression of CaLam-infected leaves of sweet orange during the symptomatic stage of infection and compared the results with previously published microarray studies that used CaLas-infected plants. Twenty candidate genes were selected to validate the expression profiles in symptomatic and asymptomatic PCR-positive leaves infected with CaLas or CaLam. Results The microarray analysis identified 633 differentially expressed genes during the symptomatic stage of CaLam infection. Among them, 418 (66%) were upregulated and 215 (34%) were down regulated. Five hundred and fourteen genes (81%) were orthologs of genes from Arabidopsis thaliana. Gene set enrichment analysis (GSEA) revealed that several of the transcripts encoded transporters associated with the endomembrane system, especially zinc transport. Among the most biologically relevant gene transcripts in GSEA were those related to signaling, metabolism and/or stimulus to hormones, genes responding to stress and pathogenesis, biosynthesis of secondary metabolites, oxidative stress and transcription factors belonging to different families. Real time PCR of 20 candidate genes validated the expression pattern of some genes in symptomatic and asymptomatic leaves infected with CaLam or CaLas. Conclusions Many gene transcripts and biological processes are significantly altered upon CaLam infection. Some of them had been identified in response to CaLas infection, while others had not been previously reported. These data will be useful for selecting target genes for genetic engineering to control HLB. PMID:23586643

  6. Citrus tissue culture employing vegetative explants.

    PubMed

    Chaturvedi, H C; Singh, S K; Sharma, A K; Agnihotri, S

    2001-11-01

    Citrus being a number one fruit of the world due to its high nutritional value, huge production of fruits and fruit products, the citrus industry may be considered a major fruit industry. Though citrus orchard area in India is comparable to USA, the produce is far less, while its export is nil. Biotechnology has played an outstanding role in boosting the citrus industry, e.g., in Spain, which is now the biggest exporter of citrus fruit with the application of micrografting. Amongst the fruit trees, perhaps the maximum tissue culture research has been done in citrus during the past four decades, however, the results of practical value are meagre. The shortfalls in citrus tissue culture research and some advancements made in this direction along with bright prospects are highlighted, restricting the review to vegetative explants only. Whilst utilization of nucellar embryogenesis is limited to rootstocks, the other aspects, like, regeneration and proliferation of shoot meristems measuring 200 microm in length--a global breakthrough--of two commercially important scion species, Citrus aurantifolia and C. sinensis and an important rootstock, C. limonia, improvement of micrografting technique, cloning of the same two scion species as well as some Indian rootstock species, employing nodal stem segments of mature trees, of immense practical value have been elaborated. A rare phenomenon of shift in the morphogenetic pattern of differentiation from shoot bud differentiation to embryoid formation occurred during the long-term culture of stem callus of C. grandis. Stem callus-regenerated plants of C. aurantifolia, C. sinensis and C. grandis showed variation in their ploidy levels and a somaclonal variant of C. sinensis, which produced seedless fruits was isolated. Tailoring of rooting in microshoots to a tap root-like system by changing the inorganic salt composition of the rooting medium, resulting in 100% transplant success, and germplasm preservation through normal growth culture of shoots of C grandis without loss of regeneration capacity during 31 years, observed so far, are some other significant results. Plants of C. aurantifolia and C. sinensis raised from shoot meristem and micrografting were grown in a nethouse and those from nodal stem segments in the field along with the in vitro-raised plants of rootstocks, namely, C. jambhiri, C. karna and C. limonia. All the plants showed normal healthy growth. Significantly enough, the meristem regenerated plants of C. aurantifolia attained the reproductive phase just in 1 year of transplantation to soil similar to those raised from nodal stem segments of mature trees, which also produced normal fruits in the subsequent year while growing under field conditions. Thus, a significant fundamental concept of a maturity factor, carried over through as small a shoot meristem as 200 microm in length to cloned plants has been demonstrated. The concept is of far-reaching significance in citrus industry besides production of pathogen-free orchards. PMID:11906099

  7. [Effect of ecological factors on citrus fruit quality].

    PubMed

    Bao, Jiangfeng; Xia, Renxue; Peng, Shu'ang

    2004-08-01

    This paper summarized the research advance on the physiological foundation of citrus fruit's major quality factors such as color formation and organic acid and sugar accumulation, and analyzed the effects of main ecological factors such as temperature, sunshine, water, soil, terrain and landforms on them. The existing problems and the research prospects of citrus ecology were expounded, and a useful proposal on the quality sub-distribution of citrus in China was put forward. PMID:15574012

  8. Citrus alongside the sinking wreckage of MV Pacific Star in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Citrus alongside the sinking wreckage of MV Pacific Star in the Pacific Ocean. Pacific Star's captain used his vessel to ram the cutter after he was ordered to stop and submit to inspection by a boarding team. Citrus was not seriously damaged in the collision. U.S. Coast Guard personnel recovered a large amount of marijuana from the wreckage - U.S. Coast Guard Cutter CITRUS, Coos Bay, Coos County, OR

  9. Citrus Production in the Lower Rio Grande Valley of Texas.

    E-print Network

    Traub, Hamilton Paul; Friend, W. H. (William Heartsill)

    1930-01-01

    LIE?ARY, A t r: COLLEGE, CAvrus. TEXAS AGRICULTURAL EXPERIMENT STATION A. B. CONNER, DIRECTOR COLLEGE STATION, BRAZOS COUNTY, TEXAS - BULLETIN NO. 419 DIVISION OF HORTICULTURE Citrus Production in the Lower Rio Grande Valley of Texas... of Agriculture. . Citrus fruit production in the Lower Rio Grande Valley, especially grapefruit, has increased at a rather rapid rate dur- ing the past few years. More than 5,000,000 citrus trees were set in orchard form in the Lower Rio Grande Valley up...

  10. In Vitro Response of Two Citrus Rootstocks to Salt Stress

    Microsoft Academic Search

    Wagdish Sh. Ghaleb; Jamal S. Sawwan; Muhanad W. Akash; Ayed M. Al-Abdallat

    2010-01-01

    The in vitro response of two citrus rootstocks (sour orange, Citrus aurantium L. and Volkamer lemon, Citrus volkameriana Ten. & Pasq.) to two types of salts (NaCl and CaCl2) of different concentrations (0, 50, 100, 150, 200, or 300 mM) was investigated. Results showed that increasing NaCl level in the growth medium led to increased Na and Cl accumulation and

  11. Monitoring fungal growth on brown rice grains using rapid and non-destructive hyperspectral imaging.

    PubMed

    Siripatrawan, U; Makino, Y

    2015-04-16

    This research aimed to develop a rapid, non-destructive, and accurate method based on hyperspectral imaging (HSI) for monitoring spoilage fungal growth on stored brown rice. Brown rice was inoculated with a non-pathogenic strain of Aspergillus oryzae and stored at 30°C and 85% RH. Growth of A. oryzae on rice was monitored using viable colony counts, expressed as colony forming units per gram (CFU/g). The fungal development was observed using scanning electron microscopy. The HSI system was used to acquire reflectance images of the samples covering the visible and near-infrared (NIR) wavelength range of 400-1000nm. Unsupervised self-organizing map (SOM) was used to visualize data classification of different levels of fungal infection. Partial least squares (PLS) regression was used to predict fungal growth on rice grains from the HSI reflectance spectra. The HSI spectral signals decreased with increasing colony counts, while conserving similar spectral pattern during the fungal growth. When integrated with SOM, the proposed HSI method could be used to classify rice samples with different levels of fungal infection without sample manipulation. Moreover, HSI was able to rapidly identify infected rice although the samples showed no symptoms of fungal infection. Based on PLS regression, the coefficient of determination was 0.97 and root mean square error of prediction was 0.39 log (CFU/g), demonstrating that the HSI technique was effective for prediction of fungal infection in rice grains. The ability of HSI to detect fungal infection at early stage would help to prevent contaminated rice grains from entering the food chain. This research provides scientific information on the rapid, non-destructive, and effective fungal detection system for rice grains. PMID:25662486

  12. Combination of multispectral remote sensing, variable rate technology and environmental modeling for citrus pest management.

    PubMed

    Du, Qian; Chang, Ni-Bin; Yang, Chenghai; Srilakshmi, Kanth R

    2008-01-01

    The Lower Rio Grande Valley (LRGV) of south Texas is an agriculturally rich area supporting intensive production of vegetables, fruits, grain sorghum, and cotton. Modern agricultural practices involve the combined use of irrigation with the application of large amounts of agrochemicals to maximize crop yields. Intensive agricultural activities in past decades might have caused potential contamination of soil, surface water, and groundwater due to leaching of pesticides in the vadose zone. In an effort to promote precision farming in citrus production, this paper aims at developing an airborne multispectral technique for identifying tree health problems in a citrus grove that can be combined with variable rate technology (VRT) for required pesticide application and environmental modeling for assessment of pollution prevention. An unsupervised linear unmixing method was applied to classify the image for the grove and quantify the symptom severity for appropriate infection control. The PRZM-3 model was used to estimate environmental impacts that contribute to nonpoint source pollution with and without the use of multispectral remote sensing and VRT. Research findings using site-specific environmental assessment clearly indicate that combination of remote sensing and VRT may result in benefit to the environment by reducing the nonpoint source pollution by 92.15%. Overall, this study demonstrates the potential of precision farming for citrus production in the nexus of industrial ecology and agricultural sustainability. PMID:17222960

  13. Isolation and characterization of Aschersonia placenta from citrus orchards and its pathogenicity towards Dialeurodes citri (Ashmead).

    PubMed

    Wang, Pingping; Song, Xuhong; Zhang, Hongyu

    2013-02-01

    For selecting potential biological agents to control Dialeurodes citri, a major insect pest in China's citrus orchards, 75 native Aschersonia isolates were selected from infected whiteflies in citrus orchards and were evaluated for virulence to third instar nymphs of D. citri at a concentration of 1 × 10(6)conidia/ml. The mortality rates of D. citri varied from 0% to 72.70%. Among the 75 Aschersonia isolates, three (HB10, HB12 and ZJ9) were the most virulent and pathogenic to D. citri and caused more than 69% mortality. The 50% lethal concentration (LC(50)) values of them were 1.86 × 10(6), 3.40 × 10(6) and 6.81 × 10(6)conidia/ml, respectively. The three isolates also produced conidia abundantly on potato dextrose agar medium (3.95 × 10(6), 6.19 × 10(6) and 7.34 × 10(6)conidia/cm(2), respectively). They were identified to be Aschersonia placenta based on their morphological analysis. Phylogenetic analysis showed that these three highly virulent Aschersonia isolates belong to a strongly supported clade that includes two other A. placenta isolates obtained from Vietnam and Thailand. In summary, these results indicate the possibility of developing the three most virulent A. placenta isolates as microbiological control agents against citrus whitefly. PMID:23160084

  14. Optimal Conditions for Cell-Free Synthesis of Citrus Exocortis Viroid and the Question of Specificity of RNA Polymerase Activity

    Microsoft Academic Search

    J. S. Semancik; K. L. Harper

    1984-01-01

    Cell-free synthesis of citrus exocortis viroid (CEV) in nuclei-rich preparations from infected Gynura aurantiaca was optimum at 18-24 degrees C. Incubation of reaction mixtures at higher temperatures (30-36 degrees C) resulted in an increase of CEV linear molecules and the recovery of incomplete or nicked newly synthesized RNA species. Although the Mg2+ optimum (2.5-5 mM) for CEV synthesis was lower

  15. Modelling the progress of Asiatic citrus canker on Tahiti lime in relation to temperature and leaf wetness

    Microsoft Academic Search

    R. S. C. Christiano; M. Dalla Pria; W. C. Jesus Junior; L. Amorim; A. Bergamin Filho

    2009-01-01

    The combined effect of temperature (15°C, 20°C, 25°C, 30°C, 35°C, 40°C and 42°C) and leaf wetness duration (0, 4, 8 12, 16,\\u000a 20 and 24 h) on infection and development of Asiatic citrus canker (Xanthomonas citri subsp. citri) on Tahiti lime plant was examined in growth chambers. No disease developed at 42°C and zero hours of leaf wetness. Periods\\u000a of leaf

  16. Identification of putative TAL effector targets of the citrus canker pathogens shows functional convergence underlying disease development and defense response

    PubMed Central

    2014-01-01

    Background Transcriptional activator-like (TAL) effectors, formerly known as the AvrBs3/PthA protein family, are DNA-binding effectors broadly found in Xanthomonas spp. that transactivate host genes upon injection via the bacterial type three-secretion system. Biologically relevant targets of TAL effectors, i.e. host genes whose induction is vital to establish a compatible interaction, have been reported for xanthomonads that colonize rice and pepper; however, citrus genes modulated by the TAL effectors PthA“s” and PthC“s” of the citrus canker bacteria Xanthomonas citri (Xc) and Xanthomonas aurantifolii pathotype C (XaC), respectively, are poorly characterized. Of particular interest, XaC causes canker disease in its host lemon (Citrus aurantifolia), but triggers a defense response in sweet orange. Results Based on, 1) the TAL effector-DNA binding code, 2) gene expression data of Xc and XaC-infiltrated sweet orange leaves, and 3) citrus hypocotyls transformed with PthA2, PthA4 or PthC1, we have identified a collection of Citrus sinensis genes potentially targeted by Xc and XaC TAL effectors. Our results suggest that similar with other strains of Xanthomonas TAL effectors, PthA2 and PthA4, and PthC1 to some extent, functionally converge. In particular, towards induction of genes involved in the auxin and gibberellin synthesis and response, cell division, and defense response. We also present evidence indicating that the TAL effectors act as transcriptional repressors and that the best scoring predicted DNA targets of PthA“s” and PthC“s” in citrus promoters predominantly overlap with or localize near to TATA boxes of core promoters, supporting the idea that TAL effectors interact with the host basal transcriptional machinery to recruit the RNA pol II and start transcription. Conclusions The identification of PthA“s” and PthC“s” targets, such as the LOB (LATERAL ORGAN BOUNDARY) and CCNBS genes that we report here, is key for the understanding of the canker symptoms development during host susceptibility, or the defenses of sweet orange against the canker bacteria. We have narrowed down candidate targets to a few, which pointed out the host metabolic pathways explored by the pathogens. PMID:24564253

  17. Diaphorina citri (Hemiptera: Psyllidae) infection and dissemination of the entomopathogenic fungus Isaria fumosorosea (Hypocreales: Cordycipitaceae)under laboratory conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A method was developed to increase efficacy and reduce grower costs when using the biological control fungal agent Paecilomyces fumosoroseus blastospores (Deuteromycotina: Hyphomycetes) to infect adult Asian citrus psyllids, Diaphorina citri (Psyllidae: Hemiptera). We analyzed the efficacy of this ‘...

  18. Contextual view showing northeastern eucalyptus windbreak and portion of citrus ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Contextual view showing northeastern eucalyptus windbreak and portion of citrus orchard. Camera facing 118" east-southeast. - Goerlitz House, 9893 Highland Avenue, Rancho Cucamonga, San Bernardino County, CA

  19. Reference Genes for Accurate Transcript Normalization in Citrus Genotypes under Different Experimental Conditions

    PubMed Central

    Mafra, Valéria; Kubo, Karen S.; Alves-Ferreira, Marcio; Ribeiro-Alves, Marcelo; Stuart, Rodrigo M.; Boava, Leonardo P.; Rodrigues, Carolina M.; Machado, Marcos A.

    2012-01-01

    Real-time reverse transcription PCR (RT-qPCR) has emerged as an accurate and widely used technique for expression profiling of selected genes. However, obtaining reliable measurements depends on the selection of appropriate reference genes for gene expression normalization. The aim of this work was to assess the expression stability of 15 candidate genes to determine which set of reference genes is best suited for transcript normalization in citrus in different tissues and organs and leaves challenged with five pathogens (Alternaria alternata, Phytophthora parasitica, Xylella fastidiosa and Candidatus Liberibacter asiaticus). We tested traditional genes used for transcript normalization in citrus and orthologs of Arabidopsis thaliana genes described as superior reference genes based on transcriptome data. geNorm and NormFinder algorithms were used to find the best reference genes to normalize all samples and conditions tested. Additionally, each biotic stress was individually analyzed by geNorm. In general, FBOX (encoding a member of the F-box family) and GAPC2 (GAPDH) was the most stable candidate gene set assessed under the different conditions and subsets tested, while CYP (cyclophilin), TUB (tubulin) and CtP (cathepsin) were the least stably expressed genes found. Validation of the best suitable reference genes for normalizing the expression level of the WRKY70 transcription factor in leaves infected with Candidatus Liberibacter asiaticus showed that arbitrary use of reference genes without previous testing could lead to misinterpretation of data. Our results revealed FBOX, SAND (a SAND family protein), GAPC2 and UPL7 (ubiquitin protein ligase 7) to be superior reference genes, and we recommend their use in studies of gene expression in citrus species and relatives. This work constitutes the first systematic analysis for the selection of superior reference genes for transcript normalization in different citrus organs and under biotic stress. PMID:22347455

  20. Innate immunity in rice

    PubMed Central

    Chen, Xuewei; Ronald, Pamela C.

    2011-01-01

    Advances in studies of rice innate immunity have led to the identification and characterization of host sensors encoding receptor kinases that perceive conserved microbial signatures. The non-RD domain, a newly recognized hallmark of these receptor kinases is highly expanded in rice (Oryza sativa) compared with Arabidopsis (Arabidopsis thaliana). Researchers have also identified a diverse array of microbial effectors from bacterial and fungal pathogens that triggers immune responses upon perception. These include both, effectors that indirectly target host Nucleotide binding site/Leucine rice repeat (NBS-LRR) proteins and transcription activator-like (TAL) effectors that directly bind promoters of host genes. Here we review the recognition and signaling events that govern rice innate immunity. PMID:21602092

  1. Citrus Canker: The Pathogen and Its Impact

    NSDL National Science Digital Library

    2002-01-01

    This Web site, currently featured on the home page of the American Phytopathological Society, contains a research report regarding the Asiatic citrus canker that has had devastating effects on Florida's citrus industry. The report, in a journal article format, thoroughly relates the natural history and current status of the disease, as well as detailing the methods and results of the (primarily genetic) experiments conducted in this study. One of the most appealing features of this Web site is the quality of the photos within the report. These photos can be viewed separately from the report in a slide show. While navigating this site is relatively straightforward, the lack of a table of contents can make finding your place in the body of the text somewhat confusing.

  2. Chemical and biological comparison of the fruit extracts of Citrus wilsonii Tanaka and Citrus medica L.

    PubMed

    Zhao, Pan; Duan, Li; Guo, Long; Dou, Li-Li; Dong, Xin; Zhou, Ping; Li, Ping; Liu, E-Hu

    2015-04-15

    Citri Fructus (CF), the mature fruit of Citrus wilsonii Tanaka (CWT) or Citrus medica L. (CML), is an important citrus by-product with health promoting and nutritive properties. The present study compares the chemical and biological differences of CWT and CML. Thin layer chromatography and high performance liquid chromatography, coupled with quadrupole time-of-flight tandem mass spectrometry techniques, were employed to compare the chemical profiles of CWT and CML. A total of 25 compounds were identified and the results indicated that there were significant differences in chemical composition between the two CF species. The quantitative results obtained by HPLC coupled with diode array detector method demonstrated that naringin was present in the highest amounts in CWT, whilst nomilin was the most dominant constituent in CML. It was also found that CWT had significantly higher free radical-scavenging activity than CML. PMID:25465994

  3. Cellular automata model for citrus variegated chlorosis

    NASA Astrophysics Data System (ADS)

    Martins, M. L.; Ceotto, G.; Alves, S. G.; Bufon, C. C. B.; Silva, J. M.; Laranjeira, F. F.

    2000-11-01

    A cellular automata model is proposed to analyze the progress of citrus variegated chlorosis epidemics in São Paulo orange plantations. In this model epidemiological and environmental features, such as motility of sharpshooter vectors that perform Lévy flights, level of plant hydric and nutritional stress, and seasonal climatic effects, are included. The observed epidemic data were quantitatively reproduced by the proposed model on varying the parameters controlling vector motility, plant stress, and initial population of diseased plants.

  4. Leadership Rice The mission of Leadership RiceistohelpRiceUniversityundergraduates

    E-print Network

    Richards-Kortum, Rebecca

    189 Leadership Rice The mission of Leadership RiceistohelpRiceUniversityundergraduates fromalldisciplinesbuildtheirleadershipcapacitiestocreateandmanage changeeffectively.LeadershipRiceexploreshowheartandmind,theoryand practice,andideasandactionscometogethertofacilitatechange. Theintroductorycourse,LEAD309Leadership: Theory to Practice (formerly UNIV309),isrequiredtoapplyforparticipationinthe

  5. Comparison of evapotranspiration rates for flatwoods and ridge citrus

    USGS Publications Warehouse

    Jia, X.; Swancar, A.; Jacobs, J.M.; Dukes, M.D.; Morgan, K.

    2007-01-01

    Florida citrus groves are typically grown in two regions of the state: flatwoods and ridge. The southern flatwoods citrus area has poorly drained fine textured sands with low organic matter in the shallow root zone. Ridge citrus is located in the northern ridge citrus zone and has fine to coarse textured sands with low water-holding capacity. Two commercial citrus groves, selected from each region, were studied from 15 July 2004 to 14 July 2005. The flatwoods citrus (FC) grove had a grass cover and used drainage ditches to remove excess water from the root zone. The ridge citrus (RC) grove had a bare soil surface with weeds periodically eliminated by tillage. Citrus crop evapotranspiration (ETc) rates at the two citrus groves were measured by the eddy correlation method, and components in the energy balance were also examined and compared. The study period had higher than average rainfall, and as a result, the two locations had similar annual ETc rates (1069 and 1044 mm for RC and FC, respectively). The ETc rates were 59% (RC) and 47% (FC) of the rainfall amounts during the study period. The annual reference crop evapotranspiration (ETo) rates were 1180 mm for RC and 1419 mm for FC, estimated using the standardized reference evapotranspiration equation. The citrus crop coefficients (Kc, ratio of ETc to ET o) were different between the two locations because of differences in latitude, ground cover, and rainfall amounts. The Kc values ranged from 0.70 between December and March to 1.05 between July and November for RC, and from 0.65 between November and May to 0.85 between June and October for FC. The results are consistent with other Kc values reported from field studies on citrus in both Florida and elsewhere using these and alternate methods.

  6. ECONOMIC IMPACT OF FLORIDA'S CITRUS INDUSTRY, 1999-2000 by Alan Hodges, Effie Philippakos, David Mulkey, Tom Spreen and Ron Muraro

    E-print Network

    Florida, University of

    ECONOMIC IMPACT OF FLORIDA'S CITRUS INDUSTRY, 1999-2000 by Alan Hodges, Effie Philippakos, David ................................................................................................................................... 3 Structure of the Florida Citrus Industry ................................................................................................... 5 Florida Citrus Producing Regions

  7. Rice University Rice Outdoor Programs and Education (ROPE) Internship

    E-print Network

    Rice University Rice Outdoor Programs and Education (ROPE) Internship Fall and Spring Semester 2012-2013 Position: Internship - Paid Location: Rice University, Houston, Texas Start Date: August 13th, 2012 End-lead students on outdoor adventure trips, aid in the teaching of a college course, and assist with supervision

  8. Global gene expression in rice blast pathogen Magnaporthe oryzae treated with a natural rice soil isolate.

    PubMed

    Spence, Carla A; Raman, Vidhyavathi; Donofrio, Nicole M; Bais, Harsh P

    2014-01-01

    The rhizospheric microbiome is comprised of many microbes, some of which reduce the virulence of their phytopathogenic neighbors; however, the mechanisms underlying these interactions are largely unknown. Rice soil isolate Pseudomonas chlororaphis EA105 strongly inhibits Magnaporthe oryzae's in vitro growth by restricting fungal diameter as well as inhibiting the formation of the appressorium, required for penetration. We were interested in elucidating M. oryzae's response to EA105 treatment, and utilized a microarray approach to obtain a global perspective of EA105 elicited changes in this pathogen. Based on this analysis, three genes of interest were knocked out in M. oryzae 70-15, and their sensitivity to EA105 treatment as well as their ability to infect rice was determined. Priming rice plants with EA105 prior to M. oryzae infection decreased lesion size, and the mutants were tested to see if this effect was retained. A null 70-15 mutant in a trichothecene biosynthesis gene showed less susceptibility to bacterial treatment, forming more appressoria than the parental type 70-15. A similar pattern was seen in a null mutant for a stress-inducible protein, MGG_03098. In addition, when this mutant was inoculated onto the leaves of EA105-primed rice plants, lesions were reduced to a greater extent than in 70-15, implicating the lack of this gene with an increased ISR response in rice. Understanding the global effect of biocontrol bacteria on phytopathogens is a key for developing successful and lasting solutions to crop loss caused by plant diseases and has the potential to greatly increase food supply. PMID:24126723

  9. DEVELOPMENT AND CHARACTERIZATION OF RICE MUTANTS ALTERED IN THE RICE BLAST RESISTANT GENE PI-TA-MEDIATED DISEASE RESISTANCE PATHWAY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Pi-ta gene in rice prevents the infection of the fungal pathogen Magnaporthe oryzae races containing the corresponding avirulence gene AVR-Pita. The Pi-ta gene encodes a putative cytoplasmic protein with a centrally localized nucleotide binding site and a leucine rich domain. AVR-Pita is a met...

  10. Rheological properties of rice-blackgram batter while replacing white rice with brown rice.

    PubMed

    Manickavasagan, Annamalai; Al-Marhubi, Insaaf Mohd; Dev, Satyanarayan

    2014-06-01

    Rice-blackgram batter is a raw material for many traditional convenience foods in Asia. Reformulation of traditional convenience food by replacing white rice with whole rice (brown rice) is a novel method to reduce the consumption of refined grain and increase the intake of whole grain in our diet. In this study, rheological properties of rice-blackgram batter was investigated while replacing white rice with brown rice at five levels (T1--0% replacement (control), T2--25% replacement, T3--50% replacement, T4--75% replacement, and T5--100% replacement). The shear stress versus shear rate plot indicates that the rice-blackgram batter exhibited non-Newtonian fluid behavior (shear thinning property) even after 100% replacement of white rice with brown rice. The rheological characteristics of rice-blackgram batters fitted reasonably well in Cassan (r2 = 0.8521-0.9856) and power law (r2 = 0.8042-0.9823) models. Brown rice replacement at all levels did not affect the flow behavior index, yield stress, consistency coefficient, and apparent viscosity of batter at 25 degrees C. However, at higher temperature, the viscosity was greater for T4 and T5 (no difference between them) than T1, T2, and T3 (no difference between them) batters. Further research is required to determine the sensory attributes and acceptability of the cooked products with brown rice-blended batter. PMID:23751544

  11. EVALUATION OF DNA AMPLIFICATION METHODS FOR IMPROVED DETECTION OF CANDIDATUS LIBERIBACTER SPECIES ASSOCIATED WITH CITRUS HUANGLONGBING

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus huanglongbing (HLB), also known as citrus greening or citrus yellow shoot, is considered the most serious disease of citrus worldwide. The disease has Asian, African and American forms caused by Candidatus Liberibacter asiaticus, Ca. L. africanus and Ca. L. americanus, respectively, which can...

  12. Citrus long-horned beetle Anoplophora chinensis Michigan State University's invasive species factsheets

    E-print Network

    Citrus long-horned beetle Anoplophora chinensis Michigan State University's invasive species State University IPM Program and M. Philip of Michigan Department of Agriculture. The citrus long. Michigan risk maps for exotic plant pests. Other common names citrus-root cerambycid, white spotted citrus

  13. First New World Documentation of an Old World Citrus Pest, the Lime Swallowtail

    E-print Network

    Farrell, Brian D.

    First New World Documentation of an Old World Citrus Pest, the Lime Swallowtail Papilio demoleus Boyce, and Brian D. Farrell Abstract. Papilio demoleus L., a well-known citrus pest in the Old World demoleus, invasive species, citrus pest. P apilio demoleus L., commonly known as the lemon, lime, citrus

  14. Transgenic Resistance to Citrus tristeza virus in Grapefruit

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grapefruit (Citrus paradisi) transgenic plants transformed with a variety of constructs derived from the Citrus tristeza virus (CTV) genome were tested for their resistance to the virus. Most transgenic lines were susceptible (27 lines), a few were partially resistant (6 lines) and only one line, tr...

  15. Establishment of Asian citrus psllid (Diaphorina citri) primary cultures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A new cell line was developed from the Asian citrus psyllid (AsCP), Diaphorina citri (Hemiptera: Psyllidae), as a novel approach to culture the bacteria associated with huanglongbing disease (HLB), also known as citrus greening disease. Methods to culture the phloem-inhabiting bacterium Candidatus L...

  16. Molecular Characterization of Citrus tristeza virus Isolates from Panama

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Twelve isolates of Citrus tristeza virus (CTV) were collected from the main citrus growing regions in Panama and characterized at the molecular level. The CTV coat protein gene (CPG) was amplified by RT-PCR, and the amplified PCR products were cloned and sequenced. The sequences analyses showed the ...

  17. FIRST REPORT OF CITRUS BLIGHT IN COSTA RICA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus blight (CB), causing a chronic decline of citrus, has been an important disease in Florida for over 100 years. CB was first reported in Brazil in the 1980s and is now responsible for the removal of nearly 10% of the trees from production annually. No causal agent has been identified, but CB h...

  18. MANAGEMENT OF CITRUS GERMPLASM/MANEJO DE GERMOPLASMA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Germplasm refers to living tissue containing genetic information that can be used to propagate future generations of plants. In the case of citrus, this usually refers to buds or seeds. Collections of different types of genotypes of citrus are maintained by genebanks for scientific use and by certif...

  19. Diversity and Phylogenetic Relationships of the Citrus Varieties Collection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Twenty-five simple sequence repeat (SSR) markers were used to detect molecular polymorphisms among 370 Citrus accessions from the Citrus Variety Collection located at The University of California, Riverside. The number of alleles detected per locus ranged from three to thirty. A total of 298 alle...

  20. Promising New Citrus Scion Selections from the USDA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Indian River Citrus league, an industry group representing citrus growers in the Indian River District of Florida, requested an update on the USDA,ARS,USHRL scion improvement program. This report describes seven scion selections that have shown potential in field trials. Among the selections d...