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Sample records for meloidogyne incognita suppression

  1. Natural suppression of Meloidogyne incognita by Pasteuria penetrans in cotton

    USDA-ARS?s Scientific Manuscript database

    The endospore-forming bacterium Pasteuria penetrans is an obligate parasite of root-knot nematodes (Meloidogyne spp.). This bacterium is commonly found in agricultural soils and has been associated with suppression of Meloidogyne spp. In a field site naturally infested with both P. penetrans and M...

  2. Mustard seed meal amendments for suppression of Meloidogyne incognita on tomato

    USDA-ARS?s Scientific Manuscript database

    Mustard seed meal is applied to soil as a fertilizer and for suppressing weeds and pathogens. Brassica juncea (Bj) ‘Pacific Gold’ and Sinapis alba (Sa) ‘IdaGold’ seed meals were tested for suppression of Meloidogyne incognita on tomato ‘BHN 444’. In greenhouse trials these treatments (all 0.25% weig...

  3. Effect of Temperature on Suppression of Meloidogyne incognita by Tagetes Cultivars.

    PubMed

    Ploeg, A T; Maris, P C

    1999-12-01

    The suppression of Meloidogyne incognita by marigolds differed among six marigold cultivars and five soil temperatures. Tagetes signata (syn. T. tenuifolia) cv. Tangerine Gem and the Tagetes hybrid Polynema allowed reproduction and root galling when grown at 30 degrees C, and should not be used for control of M. incognita at temperatures close to 30 degrees C. Tagetes patula cultivars Single Gold and Tangerine and T. erecta Flor de Muerto, when grown within a 20-30 degrees C soil temperature range, significantly reduced root galling and nematode infestation of subsequent tomato compared to tomato following fallow. When grown at 10 degrees C or 15 degrees C, only one of the tested marigold cultivars (T. erecta CrackerJack at 15 degrees C) reduced M. incognita infection of subsequent tomato compared to tomato after fallow. Marigolds should be grown at soil temperatures above 15 degrees C to suppress M. incognita infection of a subsequent crop.

  4. Effect of Temperature on Suppression of Meloidogyne incognita by Tagetes Cultivars

    PubMed Central

    Ploeg, Antoon T.; Maris, Paulus C.

    1999-01-01

    The suppression of Meloidogyne incognita by marigolds differed among six marigold cultivars and five soil temperatures. Tagetes signata (syn. T. tenuifolia) cv. Tangerine Gem and the Tagetes hybrid Polynema allowed reproduction and root galling when grown at 30 °C, and should not be used for control of M. incognita at temperatures close to 30 °C. Tagetes patula cultivars Single Gold and Tangerine and T. erecta Flor de Muerto, when grown within a 20-30 °C soil temperature range, significantly reduced root galling and nematode infestation of subsequent tomato compared to tomato following fallow. When grown at 10 °C or 15 °C, only one of the tested marigold cultivars (T. erecta CrackerJack at 15 °C) reduced M. incognita infection of subsequent tomato compared to tomato after fallow. Marigolds should be grown at soil temperatures above 15 °C to suppress M. incognita infection of a subsequent crop. PMID:19270940

  5. A Novel Meloidogyne incognita Effector Misp12 Suppresses Plant Defense Response at Latter Stages of Nematode Parasitism

    PubMed Central

    Xie, Jialian; Li, Shaojun; Mo, Chenmi; Wang, Gaofeng; Xiao, Xueqiong; Xiao, Yannong

    2016-01-01

    Secreted effectors in plant root-knot nematodes (RKNs, or Meloidogyne spp.) play key roles in their parasite processes. Currently identified effectors mainly focus on the early stage of the nematode parasitism. There are only a few reports describing effectors that function in the latter stage. In this study, we identified a potential RKN effector gene, Misp12, that functioned during the latter stage of parasitism. Misp12 was unique in the Meloidogyne spp., and highly conserved in Meloidogyne incognita. It encoded a secretory protein that specifically expressed in the dorsal esophageal gland, and highly up-regulated during the female stages. Transient expression of Misp12-GUS-GFP in onion epidermal cell showed that Misp12 was localized in cytoplast. In addition, in planta RNA interference targeting Misp12 suppressed the expression of Misp12 in nematodes and attenuated parasitic ability of M. incognita. Furthermore, up-regulation of jasmonic acid (JA) and salicylic acid (SA) pathway defense-related genes in the virus-induced silencing of Misp12 plants, and down-regulation of SA pathway defense-related genes in Misp12-expressing plants indicated the gene might be associated with the suppression of the plant defense response. These results demonstrated that the novel nematode effector Misp12 played a critical role at latter parasitism of M. incognita. PMID:27446188

  6. A Novel Meloidogyne incognita Effector Misp12 Suppresses Plant Defense Response at Latter Stages of Nematode Parasitism.

    PubMed

    Xie, Jialian; Li, Shaojun; Mo, Chenmi; Wang, Gaofeng; Xiao, Xueqiong; Xiao, Yannong

    2016-01-01

    Secreted effectors in plant root-knot nematodes (RKNs, or Meloidogyne spp.) play key roles in their parasite processes. Currently identified effectors mainly focus on the early stage of the nematode parasitism. There are only a few reports describing effectors that function in the latter stage. In this study, we identified a potential RKN effector gene, Misp12, that functioned during the latter stage of parasitism. Misp12 was unique in the Meloidogyne spp., and highly conserved in Meloidogyne incognita. It encoded a secretory protein that specifically expressed in the dorsal esophageal gland, and highly up-regulated during the female stages. Transient expression of Misp12-GUS-GFP in onion epidermal cell showed that Misp12 was localized in cytoplast. In addition, in planta RNA interference targeting Misp12 suppressed the expression of Misp12 in nematodes and attenuated parasitic ability of M. incognita. Furthermore, up-regulation of jasmonic acid (JA) and salicylic acid (SA) pathway defense-related genes in the virus-induced silencing of Misp12 plants, and down-regulation of SA pathway defense-related genes in Misp12-expressing plants indicated the gene might be associated with the suppression of the plant defense response. These results demonstrated that the novel nematode effector Misp12 played a critical role at latter parasitism of M. incognita.

  7. Brassicaceous seed meals as soil amendments to suppress the plant-parasitic nematodes Pratylenchus penetrans and Meloidogyne incognita.

    PubMed

    Zasada, I A; Meyer, S L F; Morra, M J

    2009-09-01

    Brassicaceous seed meals are the residual materials remaining after the extraction of oil from seeds; these seed meals contain glucosinolates that potentially degrade to nematotoxic compounds upon incorporation into soil. This study compared the nematode-suppressive ability of four seed meals obtained from Brassica juncea 'Pacific Gold', B. napus 'Dwarf Essex' and 'Sunrise', and Sinapis alba 'IdaGold', against mixed stages of Pratylenchus penetrans and Meloidogyne incognita second-stage juveniles (J2). The brassicaceous seed meals were applied to soil in laboratory assays at rates ranging from 0.5 to 10.0% dry w/w with a nonamended control included. Nematode mortality was assessed after 3 days of exposure and calculated as percentage reduction compared to a nonamended control. Across seed meals, M. incognita J2 were more sensitive to the brassicaceous seed meals compared to mixed stages of P. penetrans. Brassica juncea was the most nematode-suppressive seed meal with rates as low as 0.06% resulting in > 90% suppression of both plant-parasitic nematodes. In general B. napus 'Sunrise' was the least nematode-suppressive seed meal. Intermediate were the seed meals of S. alba and B. napus 'Dwarf Essex'; 90% suppression was achieved at 1.0% and 5.0% S. alba and 0.25% and 2.5% B. napus 'Dwarf Essex', for M. incognita and P. penetrans, respectively. For B. juncea, seed meal glucosinolate-degradation products appeared to be responsible for nematode suppression; deactivated seed meal (wetted and heated at 70 °C for 48 hr) did not result in similar P. penetrans suppression compared to active seed meal. Sinapis alba seed meal particle size also played a role in nematode suppression with ground meal resulting in 93% suppression of P. penetrans compared with 37 to 46% suppression by pelletized S. alba seed meal. This study demonstrates that all seed meals are not equally suppressive to nematodes and that care should be taken when selecting a source of brassicaceous seed meal

  8. Development of Multi-Component Transplant Mixes for Suppression of Meloidogyne incognita on Tomato (Lycopersicon esculentum)

    PubMed Central

    Kokalis-Burelle, N.; Martinez-Ochoa, N.; Rodríguez-Kábana, R.; Kloepper, J. W.

    2002-01-01

    The effects of combinations of organic amendments, phytochemicals, and plant-growth promoting rhizobacteria on tomato (Lycopersicon esculentum) germination, transplant growth, and infectivity of Meloidogyne incognita were evaluated. Two phytochemicals (citral and benzaldehyde), three organic amendments (pine bark, chitin, and hemicellulose), and three bacteria (Serratia marcescens, Brevibacterium iodinum, and Pseudomonas fluorescens) were assessed. Increasing rates of benzaldehyde and citral reduced nematode egg viability in vitro. Benzaldehyde was 100% efficacious as a nematicide against juveniles, whereas citral reduced juvenile viability to less than 20% at all rates tested. Benzaldehyde increased tomato seed germination and root weight, whereas citral decreased both. High rates of pine bark or chitin reduced plant growth but not seed germination, whereas low rates of chitin increased shoot length, shoot weight, and root weight; improved root condition; and reduced galling. The combination of chitin and benzaldehyde significantly improved tomato transplant growth and reduced galling. While each of the bacterial isolates contributed to increased plant growth in combination treatments, only Brevibacterium iodinum applied alone significantly improved plant growth. PMID:19265957

  9. Development of Multi-Component Transplant Mixes for Suppression of Meloidogyne incognita on Tomato (Lycopersicon esculentum).

    PubMed

    Kokalis-Burelle, N; Martinez-Ochoa, N; Rodríguez-Kábana, R; Kloepper, J W

    2002-12-01

    The effects of combinations of organic amendments, phytochemicals, and plant-growth promoting rhizobacteria on tomato (Lycopersicon esculentum) germination, transplant growth, and infectivity of Meloidogyne incognita were evaluated. Two phytochemicals (citral and benzaldehyde), three organic amendments (pine bark, chitin, and hemicellulose), and three bacteria (Serratia marcescens, Brevibacterium iodinum, and Pseudomonas fluorescens) were assessed. Increasing rates of benzaldehyde and citral reduced nematode egg viability in vitro. Benzaldehyde was 100% efficacious as a nematicide against juveniles, whereas citral reduced juvenile viability to less than 20% at all rates tested. Benzaldehyde increased tomato seed germination and root weight, whereas citral decreased both. High rates of pine bark or chitin reduced plant growth but not seed germination, whereas low rates of chitin increased shoot length, shoot weight, and root weight; improved root condition; and reduced galling. The combination of chitin and benzaldehyde significantly improved tomato transplant growth and reduced galling. While each of the bacterial isolates contributed to increased plant growth in combination treatments, only Brevibacterium iodinum applied alone significantly improved plant growth.

  10. Influence of crop production practices on Pasteuria penetrans and suppression of Meloidogyne incognita

    USDA-ARS?s Scientific Manuscript database

    Pasteuria penetrans is a parasite of root-knot nematodes (Meloidogyne spp.). Infected nematodes are not killed by the bacterium, but instead of producing eggs, females produce millions of infectious endospores. In addition to sterilizing females, P. penetrans can reduce nematode infection of roots...

  11. Dynamics of concomitant populations of Pratylenchus vulnus and Meloidogyne incognita on peach

    USDA-ARS?s Scientific Manuscript database

    The interaction between Meloidogyne incognita and Pratylenchus vulnus on nematode reproduction and vegetative growth of Prunus persica ‘Lovell’ peach was studied in field microplots. Pratylenchus vulnus suppressed the population density of M. incognita second-stage juveniles, whereas the presence o...

  12. Relationships Between Tolerance and Resistance to Meloidogyne incognita in Cotton

    PubMed Central

    Davis, R. F.; May, O. L.

    2003-01-01

    The southern root-knot nematode, Meloidogyne incognita, is the most damaging pathogen of cotton in the United States, and both resistance and tolerance to M. incognita could be valuable management approaches. Our objectives were to evaluate advanced cotton breeding lines for resistance and tolerance to M. incognita and to determine if a relationship between resistance and tolerance exists. Reproduction of M. incognita was evaluated on 17 breeding lines, a susceptible control (Delta and Pine Land DP5415), and a resistant control (M-120) in two greenhouse trials with six replications in a randomized complete block design. Two-week-old seedlings were inoculated with 8,000 M. incognita eggs and assessed for egg production 8 weeks later. Reproduction on the resistant control was only 10% of that on the susceptible control. Eight breeding lines supported 45% to 57% less (P <= 0.05) nematode reproduction than the susceptible control, and none of them were as resistant as M-120. Yield was determined in 2001 and 2002 in fumigated (1,3-dichloropropene at 56 liters/ha) and nonfumigated plots in a strip-plot design with three replications in a field naturally infested with M. incognita. Yield suppression caused by nematode infection differed among genotypes (P ≤ 0.05 for genotype × fumigation interaction). Six genotypes in 2001 and nine in 2002 were tolerant to M. incognita based on no difference in yield between the fumigated and nonfumigated plots (P ≥ 0.10). However, only three genotypes had no significant yield suppression in both years, of which two also were resistant to M. incognita. Regression analysis indicated that yield suppression decreased linearly as nematode resistance increased. PMID:19262772

  13. Suppression of the root-knot nematode [Meloidogyne incognita (Kofoid & White) Chitwood] on tomato by dual inoculation with arbuscular mycorrhizal fungi and plant growth-promoting rhizobacteria.

    PubMed

    Liu, Runjin; Dai, Mei; Wu, Xia; Li, Min; Liu, Xingzhong

    2012-05-01

    Arbuscular mycorrhizal (AM) fungi and plant growth-promoting rhizobacteria (PGPR) have potential for the biocontrol of soil-borne diseases. The objectives of this study were to quantify the interactions between AM fungi [Glomus versiforme (Karsten) Berch and Glomus mosseae (Nicol. & Gerd.) Gerdemann & Trappe] and PGPR [Bacillus polymyxa (Prazmowski) Mace and Bacillus sp.] during colonization of roots and rhizosphere of tomato (Lycopersicon esculentum Mill) plants (cultivar Jinguan), and to determine their combined effects on the root-knot nematode, Meloidogyne incognita, and on tomato growth. Three greenhouse experiments were conducted. PGPR increased colonization of roots by AM fungi, and AM fungi increased numbers of PGPR in the rhizosphere. Dual inoculations of AM fungi plus PGPR provided greater control of M. incognita and greater promotion of plant growth than single inoculations, and the best combination was G. mosseae plus Bacillus sp. The results indicate that specific AM fungi and PGPR can stimulate each other and that specific combinations of AM fungi and PGPR can interact to suppress M. incognita and disease development.

  14. Chitosan-cinnamon beads enhance suppressive activity against Rhizoctonia solani and Meloidogyne incognita in vitro.

    PubMed

    Seo, Dong-Jun; Nguyen, Dang-Minh-Chanh; Park, Ro-Dong; Jung, Woo-Jin

    2014-01-01

    A novel chitosan-cinnamon bead carrier was prepared in this study. Chitosan was mixed with cinnamon powder (CP) and cinnamon extract (CE) to obtain chitosan-cinnamon powder (CCP) beads and chitosan-cinnamon extracted (CCE) beads, respectively. The potential antifungal and nematicidal activities of CCP and CCE were investigated against Rhizoctonia solani and Meloidogyne incognita in vitro. Relative antifungal activity of the CCP (5% CP) bead-treated R. solani was 30.9 and 23.9% after 1 and 2 day incubations, respectively. Relative antifungal activity of the CCE (0.5% CE) bead-treated R. solani was 4.3, 3.0 and 4.2% after 1, 2 and 3 days of incubation. Inhibition of hatch by CCP beads with CP of 5% was 78.8%. Inhibition of hatch by CCE beads with CE of 0.5% was 82.0%. J2 mortality following the CCP (5% CP) and CCE (0.5% CE) bead treatments was 85.0 and 95.8%, respectively against M. incognita after 48 h incubations.

  15. Heterologous expression of taro cystatin protects transgenic tomato against Meloidogyne incognita infection by means of interfering sex determination and suppressing gall formation.

    PubMed

    Chan, Yuan-Li; Yang, Ai-Hwa; Chen, Jen-Tzu; Yeh, Kai-Wun; Chan, Ming-Tsair

    2010-03-01

    Plant-parasitic nematodes are a major pest of many plant species and cause global economic loss. A phytocystatin gene, Colocasia esculenta cysteine proteinase inhibitor (CeCPI), isolated from a local taro Kaosiang No. 1, and driven by a CaMV35S promoter was delivered into CLN2468D, a heat-tolerant cultivar of tomato (Solanum lycopersicum). When infected with Meloidogyne incognita, one of root-knot nematode (RKN) species, transgenic T1 lines overexpressing CeCPI suppressed gall formation as evidenced by a pronounced reduction in gall numbers. In comparison with wild-type plants, a much lower proportion of female nematodes without growth retardation was observed in transgenic plants. A decrease of RKN egg mass in transgenic plants indicated seriously impaired fecundity. Overexpression of CeCPI in transgenic tomato has inhibitory functions not only in the early RKN infection stage but also in the production of offspring, which may result from intervention in sex determination.

  16. Root Penetration by Meloidogyne incognita Juveniles Infected with Bacillus Penetrans

    PubMed Central

    Brown, Stephen M.; Smart, Grover C.

    1985-01-01

    Bacillus penetrans inhibited penetration by Meloidogyne incognita second-stage juveniles (J2) into tomato roots in the laboratory and greenhouse. Spores from this Florida population of B. penetrans attached to J2 of M. javanica, M. incognita, and M. arenaria. A greater proportion of J2 of M. javanica were infected than were J2 of either M. incognita or M. arenaria, and a greater number of spores attached to M. incognita than to M. arenaria. PMID:19294069

  17. Detection and Investigation of Soil Biological Activity against Meloidogyne incognita

    PubMed Central

    Bent, E.; Loffredo, A.; McKenry, M. V.; Becker, J. O.; Borneman, J.

    2008-01-01

    Greenhouse experiments with two susceptible hosts of Meloidogyne incognita, a dwarf tomato and wheat, led to the identification of a soil in which the root-knot nematode population was reduced 5- to 16-fold compared to identical but pasteurized soil two months after infestation with 280 M. incognita J2/100 cm3 soil. This suppressive soil was subjected to various temperature, fumigation and dilution treatments, planted with tomato, and infested with 1,000 eggs of M. incognita/100 cm3 soil. Eight weeks after nematode infestation, distinct differences in nematode population densities were observed among the soil treatments, suggesting the suppressiveness had a biological nature. A fungal rRNA gene analysis (OFRG) performed on M. incognita egg masses collected at the end of the greenhouse experiments identified 11 fungal phylotypes, several of which exhibited associations with one or more of the nematode population density measurements (egg masses, eggs or J2). The phylotype containing rRNA genes with high sequence identity to Pochonia chlamydosporia exhibited the strongest negative associations. The negative correlation between the densities of the P. chlamydosporia genes and the nematodes was corroborated by an analysis using a P. chlamydosporia-selective qPCR assay. PMID:19259527

  18. Effects of Tomato Root Exudates on Meloidogyne incognita

    PubMed Central

    Yang, Guodong; Zhou, Baoli; Zhang, Xinyu; Zhang, Zijun; Wu, Yuanyuan; Zhang, Yiming; Lü, Shuwen; Zou, Qingdao; Gao, Yuan; Teng, Long

    2016-01-01

    Plant root exudates affect root-knot nematodes egg hatch. Chemicals in root exudates can attract nematodes to the roots or result in repellence, motility inhibition or even death. However, until recently little was known about the relationship between tomato root exudates chemicals and root-knot nematodes. In this study, root exudates were extracted from three tomato rootstocks with varying levels of nematode resistance: Baliya (highly resistant, HR), RS2 (moderately resistant, MR) and L-402 (highly susceptible, T). The effects of the root exudates on Meloidogyne incognita (M. incognita) egg hatch, survival and chemotaxis of second-stage juveniles (J2) were explored. The composition of the root exudates was analysed by gas chromatography/mass spectrometry (GC/MS) prior to and following M. incognita inoculation. Four compounds in root exudates were selected for further analysis and their allopathic effect on M. incognita were investigated. Root exudates from each tomato rootstocks (HR, MR and T strains) suppressed M. incognita egg hatch and increased J2 mortality, with the highest rate being observed in the exudates from the HR plants. Exudate from HR variety also repelled M. incognita J2 while that of the susceptible plant, T, was demonstrated to be attractive. The relative amount of esters and phenol compounds in root exudates from HR and MR tomato rootstocks increased notably after inoculation. Four compounds, 2,6-Di-tert-butyl-p-cresol, L-ascorbyl 2,6-dipalmitate, dibutyl phthalate and dimethyl phthalate increased significantly after inoculation. The egg hatch of M. incognita was suppressed by each of the compound. L-ascorbyl 2,6-dipalmitate showed the most notable effect in a concentration-dependent manner. All four compounds were associated with increased J2 mortality. The greatest effect was observed with dimethyl phthalate at 2 mmol·L-1. Dibutyl phthalate was the only compound observed to repel M. incognita J2 with no effect being detected in the other

  19. Pasteuria penetrans for control of Meloidogyne incognita on tomato and cucumber, and M. arenaria on snapdragon

    USDA-ARS?s Scientific Manuscript database

    Meloidogyne incognita and Meloidogyne arenaria, are important parasitic nematodes of vegetable and ornamental crops. Field microplot and greenhouse experiments were conducted to test commercial formulations of the biocontrol agent Pasteuria penetrans for control of M. incognita on tomato and cucumbe...

  20. Dynamics of Concomitant Populations of Hoplolaimus columbus, Scutellonema brachyurum, and Meloidogyne incognita on Cotton

    PubMed Central

    Kraus-Schmidt, Helmuth; Lewis, Stephen A.

    1981-01-01

    Cotton seedlings grown in a greenhouse and a growth chamber were inoculated with Scutellonema brachyurum, Hoplolaimus columbus, and Meloidogyne incognita, singly and in all possible combinations, at two initial population (Pi) levels (100 and 300/100 cm³). S. brachyurum alone was not pathogenic to cotton at these population levels. It fed primarily as an ectoparasite but matured and reproduced within the root when it penetrated. Populations of S. brachyurum increased in the presence of H. columbus but were suppressed by M. incognita. H. columbus suppressed dry shoot weights of cotton (P = 0.05) at a Pi of 300/100 cm³ soil. Simultaneous inoculation of H. columbus with either M. incognita or S. brachyurum increased H. columbus populations over treatments with H. columbus alone, both at 60 and 90 d after inoculation. M. incognita suppressed cotton shoot weights significantly (P = 0.05) at both Pi levels. Inoculation with S. brachyurum increased M. incognita populations 60 d after inoculation, while H. columbus suppressed populations of M. incognita. Most larvae of M. incognita did not develop to maturity in the presence of H. columbus. Giant cells aborted and were necrotic 20-25 d after inoculation. Since M. incognita and H. columbus feed on different tissues, the inhibition of M. incognita may have resulted from a physiological effect of H. columbus on the host. PMID:19300720

  1. Effects of benzyl isothiocyanate on the reproduction of Meloidogyne incognita on Glycine max and Capsicum annuum

    USDA-ARS?s Scientific Manuscript database

    Reproduction of Meloidogyne incognita on Capsicum annuum or Glycine max was suppressed when infective juveniles (J2) were exposed to 0.03 millimolar benzyl isothiocyanate (BITC) for 2hr prior to inoculation of the host. Infectivity assessed by gall index was significantly reduced on both G. max (co...

  2. Nutsedge Counts Predict Meloidogyne incognita Juvenile Counts in an Integrated Management System.

    PubMed

    Ou, Zhining; Murray, Leigh; Thomas, Stephen H; Schroeder, Jill; Libbin, James

    2008-06-01

    The southern root-knot nematode (Meloidogyne incognita), yellow nutsedge (Cyperus esculentus) and purple nutsedge (Cyperus rotundus) are important pests in crops grown in the southern US. Management of the individual pests rather than the pest complex is often unsuccessful due to mutually beneficial pest interactions. In an integrated pest management scheme using alfalfa to suppress nutsedges and M. incognita, we evaluated quadratic polynomial regression models for prediction of the number of M. incognita J2 in soil samples as a function of yellow and purple nutsedge plant counts, squares of nutsedge counts and the cross-product between nutsedge counts . In May 2005, purple nutsedge plant count was a significant predictor of M. incognita count. In July and September 2005, counts of both nutsedges and the cross-product were significant predictors. In 2006, the second year of the alfalfa rotation, counts of all three species were reduced. As a likely consequence, the predictive relationship between nutsedges and M. incognita was not significant for May and July. In September 2006, purple nutsedge was a significant predictor of M. incognita. These results lead us to conclude that nutsedge plant counts in a field infested with the M. incognita-nutsedge pest complex can be used as a visual predictor of M. incognita J2 populations, unless the numbers of nutsedge plants and M. incognita are all very low.

  3. Relative Virulence of Meloidogyne incognita Host Races on Soybean

    PubMed Central

    Windham, G. L.; Barker, K. R.

    1986-01-01

    Sensitivity and host efficiency of susceptible ('Lee 68', 'Coker 156') and resistant ('Bragg', 'Centennial', 'Forrest', 'Lee 74') soybean (Glycine max (L.) Merr.) cultivars for races of Meloidogyne incognita (Mi) were determined in greenhouse experiments. Eight Mi populations collected from the southeastern United States were utilized. All Mi races reproduced readily on Lee 68 and Lee 74 and moderately on Forrest and Bragg. Coker 156 exhibited resistance to races 1 and 2, and some race 3 populations, but was very susceptible to certain race 3 and 4 populations. Reproduction of all races was lowest on Centennial. Forrest and Centennial shoot growth was not significantly suppressed by any race. There were no distinct differences in virulence between races except for a race 3 population which reproduced readily on all cultivars, stunting their growth. Considerable variation in reproduction existed within races 1 and 3. PMID:19294186

  4. Reproduction of Meloidogyne marylandi and M. incognita on several Poaceae.

    PubMed

    Faske, T R; Starr, J L

    2009-03-01

    The susceptibility of 22 plant species to Meloidogyne marylandi and M. incognita was examined in three greenhouse experiments. Inoculum of M. marylandi was eggs from cultures maintained on Zoysia matrella "Cavalier" or Cynodon dactylon x C. trasvaalensis "Tifdwarf". Inoculum of M. incognita was eggs from cultures maintained on Solanum lycopersicum 'Rutgers'. In each host test the inoculum density was 2,000 nematode eggs/pot. None of the three dicot species tested (Gossypium hirsutum, Arachis hypogaea, and S. lycopersicum) were hosts for M. marylandi but, as expected, M. incognita had high levels of reproduction on G. hirsutum and S. lycopersicum. Meloidogyne marylandi reproduced on all of the 19 grass species (Poaceae) tested but reproduction varied greatly (P = 0.05) among these hosts. The following grasses were identified for the first time as hosts for M. marylandi: Buchloe dactyloides (buffalograss), Echinochloa colona (jungle rice), Eragostis curvula (weeping lovegrass), Paspalum dilatatum (dallisgrass), P. notatum (bahiagrass), Sorghastrum, nutans (indiangrass), Tripsacum dactyloides (eastern gamagrass), and Zoysia matrella (zoysiagrass). No reproduction of M. incognita was observed on B. dactyloides, Cyndon dactylon (common bermudagrass), E. curvula, P. vaginatum (seashore paspalum), S. nutans, T. dactyloides, Z. matrella or Z. japonica. Reproduction of M. incognita was less than reproduction of M. marylandi on the other grass species, except for the Zea mays inbred line B73 on which M. incognita had greater reproduction than did M. marylandi (P = 0.05) and Stenotaphrum secundatum (St. Augustinegrass) on which M. incognita and M. marylandi had similar levels of reproduction.

  5. Screening of Carnation Cultivars for Resistance to Meloidogyne incognita.

    PubMed

    Cho, M R; Kim, J Y; Song, C; Ko, J Y; Na, S Y; Yiem, M S

    1996-12-01

    A total of 33 carnation cultivars cultured in Korea were screened for resistance to the southern root-knot nematode, Meloidogyne incognita. Carnations were tested by either inoculating with 5,000 eggs or by transplanting into a mixture of bedding medium and soil infested with an average of 435 second-stage juveniles/300 cm(3) soil. Cultivars, Desio, Castelaro, Kappa, Rara, Izu Pink, Target, and Antalia were highly resistant to M. incognita. Twelve cultivars were moderately resistant, and the remaining 14 cultivars were susceptible. These results were similar to those obtained when the cultivars were subjected to field populations of the condition on a carnation farm.

  6. Reproduction of Meloidogyne marylandi and M. incognita on several Poaceae

    PubMed Central

    Faske, T. R.

    2009-01-01

    The susceptibility of 22 plant species to Meloidogyne marylandi and M. incognita was examined in three greenhouse experiments. Inoculum of M. marylandi was eggs from cultures maintained on Zoysia matrella “Cavalier” or Cynodon dactylon x C. trasvaalensis “Tifdwarf”. Inoculum of M. incognita was eggs from cultures maintained on Solanum lycopersicum ‘Rutgers’. In each host test the inoculum density was 2,000 nematode eggs/pot. None of the three dicot species tested (Gossypium hirsutum, Arachis hypogaea, and S. lycopersicum) were hosts for M. marylandi but, as expected, M. incognita had high levels of reproduction on G. hirsutum and S. lycopersicum. Meloidogyne marylandi reproduced on all of the 19 grass species (Poaceae) tested but reproduction varied greatly (P = 0.05) among these hosts. The following grasses were identified for the first time as hosts for M. marylandi: Buchloe dactyloides (buffalograss), Echinochloa colona (jungle rice), Eragostis curvula (weeping lovegrass), Paspalum dilatatum (dallisgrass), P. notatum (bahiagrass), Sorghastrum, nutans (indiangrass), Tripsacum dactyloides (eastern gamagrass), and Zoysia matrella (zoysiagrass). No reproduction of M. incognita was observed on B. dactyloides, Cyndon dactylon (common bermudagrass), E. curvula, P. vaginatum (seashore paspalum), S. nutans, T. dactyloides, Z. matrella or Z. japonica. Reproduction of M. incognita was less than reproduction of M. marylandi on the other grass species, except for the Zea mays inbred line B73 on which M. incognita had greater reproduction than did M. marylandi (P = 0.05) and Stenotaphrum secundatum (St. Augustinegrass) on which M. incognita and M. marylandi had similar levels of reproduction. PMID:22661770

  7. Evaluation of Asteraceae Plants for Control of Meloidogyne incognita

    PubMed Central

    Tsay, T. T.; Wu, S. T.; Lin, Y. Y.

    2004-01-01

    Of the 56 species and 43 genera of Asteraceae tested, 9 were highly resistant or immune to Meloidogyne incognita and did not form root galls. Twenty-six species and six cultivars had 25% or fewer roots galled and were considered moderately resistant to M. incognita. Pre-planting Cosmos bipinnatus (F190), Gaillardia pulchella, Tagetes erecta, Tithonia diversifolia, or Zinnia elegans (F645) reduced root galling and M. incognita J2 in and around Ipomoea reptans. Amendment of soils with roots, stems, or leaves of G. pulchella was effective in controlling M. incognita on I. reptans. Tissue extracts of G. pulchella were lethal to various plant-parasitic nematodes but were innocuous to free-living nematodes. Root exudates of G. pulchella were lethal to J2 of M. incognita and were inhibitory to the hatch of eggs at the concentration of 250 ppm or higher. Gaillardia pulchella could be used to manage M. incognita as a rotation crop, a co-planted crop, or a soil amendment for control of root-knot nematode. PMID:19262785

  8. Meloidogyne incognita nematode resistance QTL in carrot

    USDA-ARS?s Scientific Manuscript database

    Root-knot nematodes (Meloidogyne spp.) are major pests attacking carrots (Daucus carota) worldwide, causing galling and forking of the storage roots, rendering them unacceptable for market. Genetic resistance could significantly reduce the need for broad-spectrum soil fumigants in carrot production....

  9. [Control effects of Ricinus communis extracts on Meloidogyne incognita].

    PubMed

    Gao, Qian-Yuan; Hu, Fei-Long; Zhu, Hong-Hong; Liu, Man-Qiang; Li, Hui-Xin; Hu, Feng

    2011-11-01

    Toxicity test and pot experiment were conducted to study the nematocidal activity and control effects of Ricinus communis extracts on Meloidogyne incognita. The results showed that both the ricinine and the R. communis water extracts had high nematocidal activity. The ricinine at concentration 2 g x L(-1) and treated for 48 hours had the strongest nematocidal activity, leading to 91.5% of corrected mortality of M. incognita and with the LC50 being 0.6 g x L(-1), whereas the R. communis water extracts at concentration 100 g x L(-1) and treated for 48 hours had the strongest nematocidal activity, which led to 83.5% of corrected mortality of M. incognita, and the LC50 was 18.3 g x L(-1). With the inoculation of M. incognita treated with ricinine, R. communis water extracts, and R. communis leaf powder, respectively, on tomato seedlings, the mean number of plant root-knots was 17.6 +/- 1.7, 20.6 +/- 1.5 and 22.8 +/- 3.7, respectively, being significantly lower than the control (37.4 +/- 2.3), and the root length increased by 46.8%, 34.5% and 33.8%, and the plant height increased by 33.5%, 22.6% and 15.8%, and the fresh mass increased by 41.4%, 18.9% and 10.1%, respectively, compared with the control. All the results suggested that R. communis extracts could mitigate the harm of M. incognita, and had obvious effects on potted tomato against M. incognita.

  10. Sensitivity of Meloidogyne incognita and Rotylenchulus reniformis to Fluopyram.

    PubMed

    Faske, T R; Hurd, K

    2015-12-01

    Fluopyram is a succinate dehydrogenase inhibitor (SDHI) fungicide that is being evaluated as a seed treatment and in-furrow spray at planting on row crops for management of fungal diseases and its effect on plant-parasitic nematodes. Currently, there are no data on nematode toxicity, nematode recovery, or effects on nematode infection for Meloidogyne incognita or Rotylenchulus reniformis after exposure to low concentrations of fluopyram. Nematode toxicity and recovery experiments were conducted in aqueous solutions of fluopyram, while root infection assays were conducted on tomato. Nematode paralysis was observed after 2 hr of exposure at 1.0 µg/ml fluopyram for both nematode species. Using an assay of nematode motility, 2-hr EC50 values of 5.18 and 12.99 µg/ml fluopyram were calculated for M. incognita and R. reniformis, respectively. Nematode recovery in motility was greater than 50% for M. incognita and R. reniformis 24 hr after nematodes were rinsed and removed from a 1-hr treatment of 5.18 and 12.99 µg/ml fluopyram, respectively. Nematode infection of tomato roots was reduced and inversely proportional to 1-hr treatments with water solutions of fluopyram at low concentrations, which ranged from 1.3 to 5.2 µg/ml for M. incognita and 3.3 to 13.0 µg/ml for R. reniformis. Though fluopyram is nematistatic, low concentrations of the fungicide were effective at reducing the ability of both nematode species to infect tomato roots.

  11. Histopathology combined with transcriptome analyses reveals the mechanism of resistance to Meloidogyne incognita in Cucumis metuliferus.

    PubMed

    Ye, De-You; Qi, Yong-Hong; Cao, Su-Fang; Wei, Bing-Qiang; Zhang, Hua-Sheng

    2017-02-20

    Root-knot nematodes (Meloidogyne spp.) cause serious threat to cucumber production. Cucumis metuliferus, a relative of cucumber, is reported to be resistant to Meloidogyne incognita, yet the underlying resistance mechanism remains unclear. In this study, the response of resistant C. metuliferus accession PI482443 following nematode infection was studied in comparison with susceptible C. sativus cv. Jinlv No.3. Roots of selected Cucumis seedings were analysed using histological and biochemical techniques. Transcriptome changes of the resistance reaction were investigated by RNA-seq. The results showed that penetration and development of the nematode in resistant plants were reduced when compared to susceptible plants. Infection of a resistant genotype with M. incognita resulted in a hypersensitive reaction. The induction of phenylalanine ammonia lyase and peroxidase activities after infection was greater in resistant than susceptible roots. Several of the most relevant genes for phenylpropanoid biosynthesis, plant hormone signal transduction, and the plant-pathogen interaction pathway that are involved in resistance to the nematode were significantly altered. The resistance in C. metuliferus PI482443 to M. incognita was associated with reduced nematode penetration, retardation of nematode development, and hypersensitive necrosis. The expression of genes resulting in the deposition of lignin, toxic compounds synthesis, cell wall reinforcement, suppression of nematode feeding and resistance protein accumulation, and activation of several transcription factors might all contribute to the resistance response to the pest. These results may lead to a better understanding of the resistance mechanism and aid in the identification of potential targets resistant to pests for cucumber improvement.

  12. GRAFTING FOR CONTROL OF MELOIDOGYNE INCOGNITA ON BELL PEPPER, TOMATO, AND MELONS

    USDA-ARS?s Scientific Manuscript database

    Greenhouse, microplot, and field trials were conducted over three-years to evaluate rootstocks for root-knot nematode (Meloidogyne incognita) resistance. Rootstocks were evaluated for bell pepper (Capsicum annuum), tomato (Solanum esculentum), cantaloupe (Cucumis melo), and watermelon (Citrullus lan...

  13. Sensitivity of Meloidogyne incognita and Rotylenchulus reniformis to Fluopyram

    PubMed Central

    Faske, T. R.; Hurd, K.

    2015-01-01

    Fluopyram is a succinate dehydrogenase inhibitor (SDHI) fungicide that is being evaluated as a seed treatment and in-furrow spray at planting on row crops for management of fungal diseases and its effect on plant-parasitic nematodes. Currently, there are no data on nematode toxicity, nematode recovery, or effects on nematode infection for Meloidogyne incognita or Rotylenchulus reniformis after exposure to low concentrations of fluopyram. Nematode toxicity and recovery experiments were conducted in aqueous solutions of fluopyram, while root infection assays were conducted on tomato. Nematode paralysis was observed after 2 hr of exposure at 1.0 µg/ml fluopyram for both nematode species. Using an assay of nematode motility, 2-hr EC50 values of 5.18 and 12.99 µg/ml fluopyram were calculated for M. incognita and R. reniformis, respectively. Nematode recovery in motility was greater than 50% for M. incognita and R. reniformis 24 hr after nematodes were rinsed and removed from a 1-hr treatment of 5.18 and 12.99 µg/ml fluopyram, respectively. Nematode infection of tomato roots was reduced and inversely proportional to 1-hr treatments with water solutions of fluopyram at low concentrations, which ranged from 1.3 to 5.2 µg/ml for M. incognita and 3.3 to 13.0 µg/ml for R. reniformis. Though fluopyram is nematistatic, low concentrations of the fungicide were effective at reducing the ability of both nematode species to infect tomato roots. PMID:26941460

  14. Effect of Crotalaria juncea Amendment on Squash Infected with Meloidogyne incognita

    PubMed Central

    Wang, K.-H.; McSorley, R.; Gallaher, R. N.

    2004-01-01

    Two greenhouse experiments were conducted to examine the effect of Crotalaria juncea amendment on Meloidogyne incognita population levels and growth of yellow squash (Cucurbita pepo). In the first experiment, four soils with a long history of receiving yard waste compost (YWC+), no-yard-waste compost (YWC-), conventional tillage, or no-tillage treatments were used; in the second experiment, only one recently cultivated soil was used. Half of the amount of each soil received air-dried residues of C. juncea as amendment before planting squash, whereas the other half did not. Crotalaria juncea amendment increased squash shoot and root weights in all soils tested, except in YWC+ soil where the organic matter content was high without the amendment. The amendment suppressed the numbers of M. incognita if the inoculum level was low, and when the soil contained relatively abundant nematode-antagonistic fungi. Microwaved soil resulted in greater numbers of M. incognita and free-living nematodes than frozen or untreated soil, indicating nematode-antagonistic microorganisms played a role in nematode suppression. The effects of C. juncea amendment on nutrient cycling were complex. Amendment with C. juncea increased the abundance of free-living nematodes and Harposporium anguillulae, a fungus antagonistic to them in the second experiment but not in the first experiment. Soil histories, especially long-term yard waste compost treatments that increased soil organic matter, can affect the performance of C. juncea amendment. PMID:19262819

  15. Effect of Crotalaria juncea Amendment on Squash Infected with Meloidogyne incognita.

    PubMed

    Wang, K-H; McSorley, R; Gallaher, R N

    2004-09-01

    Two greenhouse experiments were conducted to examine the effect of Crotalaria juncea amendment on Meloidogyne incognita population levels and growth of yellow squash (Cucurbita pepo). In the first experiment, four soils with a long history of receiving yard waste compost (YWC+), no-yard-waste compost (YWC-), conventional tillage, or no-tillage treatments were used; in the second experiment, only one recently cultivated soil was used. Half of the amount of each soil received air-dried residues of C. juncea as amendment before planting squash, whereas the other half did not. Crotalaria juncea amendment increased squash shoot and root weights in all soils tested, except in YWC+ soil where the organic matter content was high without the amendment. The amendment suppressed the numbers of M. incognita if the inoculum level was low, and when the soil contained relatively abundant nematode-antagonistic fungi. Microwaved soil resulted in greater numbers of M. incognita and free-living nematodes than frozen or untreated soil, indicating nematode-antagonistic microorganisms played a role in nematode suppression. The effects of C. juncea amendment on nutrient cycling were complex. Amendment with C. juncea increased the abundance of free-living nematodes and Harposporium anguillulae, a fungus antagonistic to them in the second experiment but not in the first experiment. Soil histories, especially long-term yard waste compost treatments that increased soil organic matter, can affect the performance of C. juncea amendment.

  16. Impact of Soil Texture on the Reproductive and Damage Potentials of Rotylenchulus reniformis and Meloidogyne incognita on Cotton

    PubMed Central

    Koenning, S. R.; Walters, S. A.; Barker, K. R.

    1996-01-01

    The effects of soil type and initial inoculum density (Pi) on the reproductive and damage potentials of Meloidogyne incognita and Rotylenchulus reniformis on cotton were evaluated in microplot experiments from 1991 to 1993. The equilibrium nematode population density for R. reniformis on cotton was much greater than that of M. incognita, indicating that cotton is a better host for R. reniformis than M. incognita. Reproduction of M. incognita was greater in coarse-textured soils than in fine-textured soils, whereas R. reniformis reproduction was greatest in a Portsmouth loamy sand with intermediate percentages of clay plus silt. Population densities of M. incognita were inversely related to the percentage of silt and clay, but R. reniformis was favored by moderate levels of clay plus silt (ca. 28%). Both M. incognita races 3 and 4 and R. reniformis effected suppression of seed-cotton yield in all soil types evaluated. Cotton-yield suppression was greatest in response to R. reniformis at high Pi. Cotton maturity, measured as percentage of open bolls at different dates, was affected by the presence of nematodes in all 3 years. PMID:19277171

  17. Extraction of Root-associated Meloidogyne incognita and Rotylenchulus reniformis

    PubMed Central

    Stetina, S. R.; McGawley, E. C.; Russin, J. S.

    1997-01-01

    A technique based on physical maceration of root tissue was developed to extract vermiform and swollen stages of Meloidogyne incognita and Rotylenchulus reniformis. Experiments conducted on soybean and tomato evaluated the efficiency of method (stir, grind), NaOC1 concentration (0%, 0.5%), and duration (lx, 2x) on extraction of nematodes and eggs from 60-day-old populations. Root-associated populations of R. reniformis were considerably lower than those of M. incognita, so development of the method focused on the latter. Grinding liberated more nematodes than stirring, but the reverse was true for egg extraction. Among grinding treatments, a duration of 10 seconds in 0.5% NaOCl provided the most efficient extraction of nematodes and eggs. Among stirring treatments, a duration of 10 minutes in 0.5% NaOCl provided the most efficient extraction of eggs. These techniques were compared on soybean roots 30 days older than those on which the procedures were first evaluated, with consistent results. PMID:19274151

  18. Resistance in Selected Corn Hybrids to Meloidogyne arenaria and M. incognita

    PubMed Central

    Davis, R. F.; Timper, P.

    2000-01-01

    A total of 33 corn hybrids were evaluated in a series of greenhouse and field trials to determine if they differed in resistance to either Meloidogyne incognita race 3 or M. arenaria race 1. Reproduction of M. incognita race 3 and M. arenaria race 1 on the hybrids was also compared. Reproduction of M. arenaria differed among corn hybrids after 58 to 65 days in greenhouse experiments; however, reproduction was similar among hybrids in the field experiment. No hybrids were consistently resistant to M. incognita. Two isolates of M. arenaria and two of M. incognita were evaluated in the greenhouse trials, and no evidence of isolate-dependent resistance was observed. Meloidogyne incognita reproduced better than M. arenaria on the hybrids in this study. A survey of 102 corn fields from 11 counties throughout southern Georgia was conducted to determine the relative frequency of M. incognita and M. arenaria. Meloidogyne species were found in 34 of the fields surveyed, and 93.9% of these were identified as M. incognita. The frequency of occurrence of M. incognita was 99.6% if the previous crop was cotton and 84.6% if the previous crop was peanut. Pratylenchus spp. were extracted from all intact corn root systems examined. PMID:19271019

  19. Phenotypic Expression of rkn1-Mediated Meloidogyne incognita Resistance in Gossypium hirsutum Populations

    PubMed Central

    Wang, C.; Matthews, W. C.; Roberts, P. A.

    2006-01-01

    The root-knot nematode Meloidogyne incognita is a damaging pest of cotton (Gossypium hirsutum) worldwide. A major gene (rkn1) conferring resistance to M. incognita was previously identified on linkage group A03 in G. hirsutum cv. Acala NemX. To determine the patterns of segregation and phenotypic expression of rkn1, F1, F2, F2:3, BC1F1 and F2:7 recombinant inbred lines (RIL) from intraspecific crosses between Acala NemX and a closely related susceptible cultivar Acala SJ-2 were inoculated in greenhouse tests with M. incognita race 3. The resistance phenotype was determined by the extent of nematode-induced root galling and nematode egg production on roots. Suppression of root galling and egg production was highly correlated among individuals in all tests. Root galling and egg production on heterozygous plants did not differ from the susceptible parent phenotype 125 d or more after inoculation, but were slightly suppressed with shorter screening (60 d), indicating that rkn1 behaved as a recessive gene or an incompletely recessive gene, depending on the screening condition. In the RIL, rkn1 segregated in an expected 1 resistant: 1 susceptible ratio for a major resistance gene. However, within the resistant class, 21 out of 34 RIL were more resistant than the resistant parent Acala NemX, indicating transgressive segregation. These results suggest that rkn1-based resistance in G. hirsutum can be enhanced in progenies of crosses with susceptible genotypes. Allelism tests and molecular genetic analysis are needed to determine the relationship of rkn1 to other M. incognita resistance sources in cotton. PMID:19259455

  20. Survival of Paecilomyces lilacinus in Selected Carriers and Related Effects on Meloidogyne incognita on Tomato

    PubMed Central

    Cabanillas, Enrique; Barker, K. R.; Nelson, L. A.

    1989-01-01

    Laboratory and microplot experiments were conducted to determine the influence of carrier and storage of Paecilomyces lilacinus on its survival and related protection of tomato against Meloidogyne incognita. Spores of P. lilacinus were prepared in five formulations: alginate pellets (pellets), diatomaceous earth granules (granules), wheat grain, soil, and soil plus chitin. Fungal viability was high in wheat and granules, intermediate in pellets, and low in soil and chitin-amended soil stored at 25 ± 2 C. In 1985 P. lilacinus in field microplots resulted in about a 25% increase in tomato yield and 25% gall suppression, compared with nematodes alone. Greatest suppression of egg development occurred in plots treated with P. lilacinus in pellets, wheat grain, and granules. In 1986 carryover protection of tomato against M. incognita resulted in about a threefold increase in tomato fruit yield and 25% suppression of gall development, compared with plants treated with nematodes alone. Higher numbers of fungus-infected egg masses occurred in plots treated with pellets (32%) than in those treated with chitin-amended soil (24%), wheat (16%), granules (12%), or soil (7%). Numbers of fungal colony-forming units per gram of soil in plots treated with pellets were 10-fold greater than initial levels estimated at planting time in 1986. PMID:19287586

  1. Host Suitability of Soybean Cultivars for Meloidogyne incognita and M. arenaria.

    PubMed

    Kirkpatrick, T L; May, M L

    1989-10-01

    The suitability of five maturity group (MG) III and five MG IV soybean, Glycine max, cultivars as hosts for Meloidogyne incognita and M. arenaria was evaluated in a greenhouse. 'Forrest', a MG V cultivar, was used as the standard of comparison for M. incognita resistance. With M. incognita, root-gall and egg-mass indices and reproductive factors for 'Asgrow 3307', 'FFR 398', and 'Pioneer 9442' were comparable with those found on Forrest. Meloidogyne arenaria reproduction was lower (P incognita, the relative ranking of the cultivars was similar to the greenhouse results.

  2. Effects of Concomitant Development on Reproduction of Meloidogyne incognita and Rotylenchulus reniformis on Sweet Potato

    PubMed Central

    Thomas, Ronald J.; Clark, Christopher A.

    1983-01-01

    The influence of various factors on reproduction of concomitant Meloidogyne incognita (Mi) and Rotylenchulus reniformis (Rr) on sweet potato were studied in the greenhouse. Reproduction of Rr was reduced by Mi at all inoculum levels and experiment durations used, while Mi reproduction was not inhibited. Both species failed to affect each other when inoculated simultaneously onto root systems developed in separate pots from different nodes of the same plant. Reproduction of each species was not significantly greater when inoculation of the second species was delayed 1-2 weeks compared to simultaneous inoculation. After shoot excision, Rr increased in the soil but Mi decreased. Fibrous root weights of plants inoculated with Rr + Mi in some tests were higher than those inoculated with Mi alone, indicating an early suppression of Mi and/or root stintulation by Rr. Drought stress delayed Rr egg hatching and movement of larvae into the soil, but had little effect on Mi reproduction. PMID:19295794

  3. Interaction between Meloidogyne incognita and Fusarium oxysporum f. sp. phaseoli on Selected Bean Genotypes

    PubMed Central

    France, R. A.; S.Abawi, G.

    1994-01-01

    Four bean genotypes (IPA-1, A-107, A-211, and Calima), representing all possible combinations of resistance and susceptibility to Fusarium oxysporum f. sp. phaseoli (Fop) and Meloidogyne incognita, were each inoculated with three population densities of these pathogens. Calima and A-107 were resistant to Fop; A-107 and A-211 were resistant to M. incognita; and IPA-1 was susceptible to both pathogens. In Fop-susceptible lines (IPA-1 and A-211), the presence of M. incognita contributed to an earlier onset and increased severity of Fusarium wilt symptoms and plant stunting. However, the Fop-resistant Calima developed symptoms of Fusarium wilt only in the presence of M. incognita. Genotype A-107 (resistant to both M. incognita and Fop) exhibited Fusarium wilt symptoms and a moderately susceptible reaction to Fop only after the breakdown of its M. incognita resistance by elevated incubation temperatures (27 C). Root galling and reproduction of M. incognita was generally increased as inoculum density of M. incognita was increased on the M. incognita susceptible cultivars. However, these factors were decreased as the inoculum density of Fop was increased. It was concluded that severe infections of bean roots by M. incognita increase the severity of Fusarium wilt on Fop-susceptible genotypes and may modify the resistant reaction to Fop. PMID:19279917

  4. Interaction between Meloidogyne incognita and Fusarium oxysporum f. sp. phaseoli on Selected Bean Genotypes.

    PubMed

    France, R A; S Abawi, G

    1994-12-01

    Four bean genotypes (IPA-1, A-107, A-211, and Calima), representing all possible combinations of resistance and susceptibility to Fusarium oxysporum f. sp. phaseoli (Fop) and Meloidogyne incognita, were each inoculated with three population densities of these pathogens. Calima and A-107 were resistant to Fop; A-107 and A-211 were resistant to M. incognita; and IPA-1 was susceptible to both pathogens. In Fop-susceptible lines (IPA-1 and A-211), the presence of M. incognita contributed to an earlier onset and increased severity of Fusarium wilt symptoms and plant stunting. However, the Fop-resistant Calima developed symptoms of Fusarium wilt only in the presence of M. incognita. Genotype A-107 (resistant to both M. incognita and Fop) exhibited Fusarium wilt symptoms and a moderately susceptible reaction to Fop only after the breakdown of its M. incognita resistance by elevated incubation temperatures (27 C). Root galling and reproduction of M. incognita was generally increased as inoculum density of M. incognita was increased on the M. incognita susceptible cultivars. However, these factors were decreased as the inoculum density of Fop was increased. It was concluded that severe infections of bean roots by M. incognita increase the severity of Fusarium wilt on Fop-susceptible genotypes and may modify the resistant reaction to Fop.

  5. Chemical-Mediated Toxicity of N-Viro Soil to Heterodera glycines and Meloidogyne incognita

    PubMed Central

    Zasada, I. A.; Tenuta, M.

    2004-01-01

    N-Viro Soil (NVS) is an alkaline-stabilized municipal biosolid that has been shown to lower population densities and reduce egg hatch of Heterodera glycines and other plant-parasitic nematodes; but the mechanism(s) of nematode suppression of this soil amendment are unknown. This study sought to identify NVS-mediated changes in soil chemical properties and their impact upon H. glycines and Meloidogyne incognita mortality. N-Viro Soil was applied to sand in laboratory assays at 0.5%, 1.0%, 2.0%, and 3.0% dry w/w with a nonamended treatment as a control. Nematode mortality and changes in sand-assay chemical properties were determined 24 hours after incubation. Calculated lethal concentration (LC90) values were 1.4% w/w NVS for second-stage juveniles of both nematode species and 2.6 and >3.0% w/w NVS for eggs of M. incognita and H. glycines, respectively. Increasing rates of NVS were strongly correlated (r² = 0.84) with higher sand solution pH levels. Sand solution pH levels and, to a lesser extent, the production of ammonia appeared to be the inorganic chemical-mediated factors responsible for killing plant-parasitic nematodes following amendment with NVS. PMID:19262820

  6. Mustard seed meal mixtures: management of Meloidogyne incognita on pepper and potential phytotoxicity.

    PubMed

    Meyer, Susan L F; Zasada, Inga A; Orisajo, Samuel B; Morra, Matthew J

    2011-03-01

    Meals produced when oil is extracted from seeds in the Brassicaceae have been shown to suppress weeds and soilborne pathogens. These seed meals are commonly used individually as soil amendments; the goal of this research was to evaluate seed meal mixes of Brassica juncea (Bj) and Sinapis alba (Sa) against Meloidogyne incognita. Seed meals from Bj 'Pacific Gold' and Sa 'IdaGold' were tested alone and in combinations to determine rates and application times that would suppress M. incognita on pepper (Capsicum annuum) without phytotoxicity. Rates of soil application (% w/w) for the phytotoxicity study were: 0.5 Sa, 0.2 Bj, 0.25 Sa + 0.25 Bj, 0.375 Sa + 0.125 Bj, 0.125 Sa + 0.375 Bj, and 0, applied 0 - 5 weeks before transplant. Overall, 0.2% Bj was the least toxic meal to pepper seedlings. By comparison, 0.5% S. alba seed meal did not reduce lettuce (Lactuca sativa) seed germination at week 0, but all seed meal treatments containing B. juncea prevented or significantly reduced germination at week 0. The seed meals did not affect lettuce seed germination at weeks 1-5, but hypocotyl growth was reduced by all except 0.2% Bj at weeks 1, 4 and 5. Brassica juncea and Sa meals were tested for M. incognita suppression at 0.2, 0.15, 0.1 and 0.05%; mixtures were 0.1% Sa + 0.1% Bj, 0.15% Sa + 0.05% Bj, and 0.05% Sa + 0.15% Bj. All treatments were applied 2 weeks before transplant. The 0.2% Bj and 0.05% Sa + 0.15% Bj treatments overall had the longest shoots and highest fresh weights. Eggs per g root were lowest with 0.1 - 0.2% Bj amendments and the seed meal mixtures. The results indicate that Bj and some Bj + Sa mixtures can be applied close to transplant to suppress M. incognita populations on pepper; consequently, a seed meal mixture could be selected to provide activity against more than one pest or pathogen. For pepper, care should be taken in formulating mixtures so that Sa rates are low compared to Bj.

  7. Mustard seed meal mixtures: management of Meloidogyne incognita on pepper and potential phytotoxicity

    PubMed Central

    Zasada, Inga A.; Orisajo, Samuel B.; Morra, Matthew J.

    2011-01-01

    Meals produced when oil is extracted from seeds in the Brassicaceae have been shown to suppress weeds and soilborne pathogens. These seed meals are commonly used individually as soil amendments; the goal of this research was to evaluate seed meal mixes of Brassica juncea (Bj) and Sinapis alba (Sa) against Meloidogyne incognita. Seed meals from Bj ‘Pacific Gold’ and Sa ‘IdaGold’ were tested alone and in combinations to determine rates and application times that would suppress M. incognita on pepper (Capsicum annuum) without phytotoxicity. Rates of soil application (% w/w) for the phytotoxicity study were: 0.5 Sa, 0.2 Bj, 0.25 Sa + 0.25 Bj, 0.375 Sa + 0.125 Bj, 0.125 Sa + 0.375 Bj, and 0, applied 0 – 5 weeks before transplant. Overall, 0.2% Bj was the least toxic meal to pepper seedlings. By comparison, 0.5% S. alba seed meal did not reduce lettuce (Lactuca sativa) seed germination at week 0, but all seed meal treatments containing B. juncea prevented or significantly reduced germination at week 0. The seed meals did not affect lettuce seed germination at weeks 1-5, but hypocotyl growth was reduced by all except 0.2% Bj at weeks 1, 4 and 5. Brassica juncea and Sa meals were tested for M. incognita suppression at 0.2, 0.15, 0.1 and 0.05%; mixtures were 0.1% Sa + 0.1% Bj, 0.15% Sa + 0.05% Bj, and 0.05% Sa + 0.15% Bj. All treatments were applied 2 weeks before transplant. The 0.2% Bj and 0.05% Sa + 0.15% Bj treatments overall had the longest shoots and highest fresh weights. Eggs per g root were lowest with 0.1 – 0.2% Bj amendments and the seed meal mixtures. The results indicate that Bj and some Bj + Sa mixtures can be applied close to transplant to suppress M. incognita populations on pepper; consequently, a seed meal mixture could be selected to provide activity against more than one pest or pathogen. For pepper, care should be taken in formulating mixtures so that Sa rates are low compared to Bj. PMID:22791910

  8. Control of Meloidogyne incognita Using Mixtures of Organic Acids

    PubMed Central

    Seo, Yunhee; Kim, Young Ho

    2014-01-01

    This study sought to control the root-knot nematode (RKN) Meloidogyne incognita using benign organo-chemicals. Second-stage juveniles (J2) of RKN were exposed to dilutions (1.0%, 0.5%, 0.2%, and 0.1%) of acetic acid (AA), lactic acid (LA), and their mixtures (MX). The nematode bodies were disrupted severely and moderately by vacuolations in 0.5% of MX and single organic acids, respectively, suggesting toxicity of MX may be higher than AA and LA. The mortality of J2 was 100% at all concentrations of AA and MX and only at 1.0% and 0.5% of LA, which lowered slightly at 0.2% and greatly at 0.1% of LA. This suggests the nematicidal activity of MX may be mostly derived from AA together with supplementary LA toxicity. MX was applied to chili pepper plants inoculated with about 1,000 J2, for which root-knot gall formations and plant growths were examined 4 weeks after inoculation. The root gall formation was completely inhibited by 0.5% MX and standard and double concentrations of fosthiazate; and inhibited 92.9% and 57.1% by 0.2% and 0.1% MX, respectively. Shoot height, shoot weight, and root weight were not significantly (P ≤ 0.05) different among all treatments and the untreated and non-inoculated controls. All of these results suggest that the mixture of the organic acids may have a potential to be developed as an eco-friendly nematode control agent that needs to be supported by the more nematode control experiments in fields. PMID:25506312

  9. Behavioral differences of Heterodera glycines and Meloidogyne incognita infective juveniles exposed to root extracts in vitro

    USDA-ARS?s Scientific Manuscript database

    The in vitro behaviors of infective juveniles (J2) of Heterodera glycines and Meloidogyne incognita were compared in the presence and absence of plant root extracts. In an agar plate attraction-retention assay, H. glycines was 15-fold more responsive to a chemical attractant (CaCl2; P < 0.05) than w...

  10. Glucosinolate content and nematicidal activity of Brazilian wild mustard tissues against Meloidogyne incognita in tomato

    USDA-ARS?s Scientific Manuscript database

    The wild mustard (Brassica juncea L.), an invasive weed of winter crops in Brazil, was evaluated for glucosinolate content of its plant tissues and nematicidal activity of its dry leaf meal (LM), whole seed meal (WSM) and hexane defatted seed meal (DSM) against Meloidogyne incognita on tomato plants...

  11. Tolerance of sweet sorghum to Meloidogyne incognita and crop effect on nematode population density

    USDA-ARS?s Scientific Manuscript database

    Sweet sorghum (Sorghum bicolor) is a sugar-producing crop that can be used for biofuel and plastics production, and the crop could be incorporated into annual cropping systems in the southern US. The effect of Meloidogyne incognita on sweet sorghum yield and sugar content has not been reported. Beca...

  12. Virulence of Meloidogyne incognita to expression of N gene in pepper

    USDA-ARS?s Scientific Manuscript database

    Five root-knot nematode resistant pepper genotypes and three susceptible pepper genotypes were compared for their reactions against a population of Meloidogyne incognita (Chitwood) Kofoid and White which had been shown to be pathogenic to bell pepper (Capsicum annuum) in preliminary tests. The pepp...

  13. Lack of influence of Meloidogyne incognita on resistance of bell pepper cultivars to Phytophthora capsici

    USDA-ARS?s Scientific Manuscript database

    The root-knot nematode, Meloidogyne incognita (Mi), and the Phytophthora blight pathogen, Phytophthora capsici (Pc), cause root diseases in bell pepper under natural field conditions. However, the interactions between these two pathogens on different bell pepper genotypes are not clear. Greenhouse e...

  14. Evaluating the predatory potential of carnivorous nematodes against Rotylenchulus reniformis and Meloidogyne incognita

    USDA-ARS?s Scientific Manuscript database

    Predatory behavior of a nematode is usually determined through gut content observation or prey delimitation counts. In this experiment, Mononchus and Neoactinolaimus predation of Rotylenchulus reniformis or Meloidogyne incognita was determined using a PCR-based nematode gut content analysis. Soil sa...

  15. Interactions of Heterodera daverti, H. goldeni and H. zeae with Meloidogyne incognita on rice

    USDA-ARS?s Scientific Manuscript database

    The interactions of the cyst nematodes Heterodera daverti, H. goldeni and H. zeae with the root-knot nematode Meloidogyne incognita on rice (Oryza sativa) cultivars Giza 178 and Sakha 101 were studied in the greenhouse. Inoculation with H. goldeni alone or one week before inoculation with M. incogni...

  16. Pathogenicity of Heterodera daverti, H. zeae, and Meloidogyne incognita on rice

    USDA-ARS?s Scientific Manuscript database

    The reactions of five rice cultivars to the cyst nematodes Heterodera daverti and H. zeae and the root-knot nematode Meloidogyne incognita were determined in the greenhouse. The results showed that both H. daverti and H. zeae infected and reproduced successfully on some of the tested rice cultivars....

  17. Microplot Evaluation of Rootstocks for Control of Meloidogyne incognita on Grafted Tomato, Muskmelon, and Watermelon

    USDA-ARS?s Scientific Manuscript database

    Microplot experiments were conducted over two years (four growing seasons) to evaluate Meloidogyne incognita resistance in rootstocks used for grafted tomato (Solanum lycopersicum), muskmelon (Cucumis melo), and watermelon (Citrullus lanatus). Three tomato rootstocks; ‘TX301’, ‘Multifort’, and ‘Alo...

  18. Efficacy of rootstocks for control of Meloidogyne incognita on grafted tomato and cantaloupe

    USDA-ARS?s Scientific Manuscript database

    A microplot experiment was conducted to evaluate root-knot nematode (Meloidogyne incognita) resistance in rootstocks used for producing grafted tomato (Solanum esculentum) and muskmelon (Cucumis melo). Three tomato rootstocks including ‘TX301’ (Syngenta Seeds), ‘Multifort’ (De Ruiter Seeds), and ‘A...

  19. Protease inhibition by Heterodera glycines cyst content: evidence for effects on the Meloidogyne incognita proteasome

    USDA-ARS?s Scientific Manuscript database

    Proteases from Heterodera glycines and Meloidogyne incognita juveniles were inhibited by heat-stable content of H. glycines female cysts (HglCE), and by the plant polyphenol epigallocatechin gallate (EGCG). General protease activities detected using the nematode peptide KSAYMRFa were inhibited by EG...

  20. Susceptibility of several common subtropical weeds to Meloidogyne incognita, M. arenaria, and M. javanica

    USDA-ARS?s Scientific Manuscript database

    Experiments were conducted in the greenhouse to assess galling and egg production of three root-knot nematode species, Meloidogyne incognita, M. arenaria, and M. javanica, on several weeds common to Florida agricultural land. Weeds evaluated were Amaranthus retroflexus (redroot pigweed), Aeschynomen...

  1. Reaction of Prunus Rootstocks to Meloidogyne incognita and M. arenaria in Spain

    PubMed Central

    Marull, J.; Pinochet, J.; Verdejo-Lucas, S.; Soler, A.

    1991-01-01

    Prunus rootstocks were evaluated for their reaction to Meloidogyne incognita and M. arenaria. Most rootstocks were peach-almond hybrids of Spanish origin. In one experiment three selections of Garfi x Nemared (G x N) and Hansen-5 were highly resistant to M. incognita, but four other rootstocks were susceptible showing high galling indices and population increases. In two experiments with M. arenaria, the hybrid selections G x N nos. 1 and 9 were immune, GF-305 and Hansen-5 were resistant, but nine other rootstocks expressed various degrees of susceptibility. All Spanish rootstocks were susceptible to both Meloidogyne species except for the three G x N selections. The root-knot nematode resistant peach Nemared used as a male parent with Garfi was found to transmit a high degree of resistance to M. incognita and immunity to M. arenaria. Progenies of P. davidiana (Ga x D no. 3), a known source of resistance to root-knot nematodes, were susceptible. PMID:19283164

  2. Meloidogyne incognita and M. arenaria Reproduction on Dwarf Hollies and Lantana

    PubMed Central

    Williams-Woodward, J. L.; Davis, R. F.

    2001-01-01

    Meloidogyne incognita and M. arenaria reproduction and host plant tolerance were assessed in field and greenhouse experiments on seven holly cultivars including Ilex glabra 'Shamrock', I. vomitoria 'Schelling's Dwarf', I. cornuta 'Carissa', red holly hybrid (Ilex Little Red™), and I. crenata 'Compacta', 'Green Luster', and 'Helleri' as well as Japanese boxwood (Buxus microphylla) and two lantana cultivars (Lantana camara 'Miss Huff' and 'New Gold'). Boxwood had the highest M. arenaria and M. incognita gall rating of any of the plants evaluated. Gall ratings from M. arenaria and M. incognita on I. crenata 'Green Luster' and 'Helleri' were not different from boxwood. Ilex crenata 'Compacta' had less root galling than boxwood, but the roots averaged up to 20% galling by M. incognita and 30% galling by M. arenaria. Ilex glabra 'Shamrock', I. vomitoria 'Schelling's Dwarf', I. cornuta 'Carissa', Ilex Little Red™, and the two lantana cultivars had little or no root galling after 2 years of growth. Neither M. incognita nor M. arenaria affected the growth of any of the plants evaluated in the field or greenhouse. Reproduction of M. incognita was much lower than that of M. arenaria on the holly cultivars. Nematode reproduction in the greenhouse was greatest on the three I. crenata cultivars, followed by Ilex Little Red™ and B. microphylla. Ilex glabra 'Shamrock', I. vomitoria 'Schelling's Dwarf', I. cornuta 'Carissa', and L. camara 'Miss Huff' and 'New Gold' could be useful as Meloidogyne-resistant landscape plants. PMID:19265898

  3. Evaluation of roselle (Hibiscus sabdariffa) leaf and pomegranate (Punica granatum) fruit rind for activity against Meloidogyne incognita

    USDA-ARS?s Scientific Manuscript database

    Pomegranate (Punica granatum) fruit and roselle (Hibiscus sabdariffa) leaves have been used in traditional medicine, including as anthelmintics. Methanolic extracts from these plants were investigated for activity against the southern root-knot nematode (RKN) Meloidogyne incognita. Dried, ground p...

  4. Pathogenicity of Macrophomina phaseoli on Jute in the Presence of Meloidogyne incognita and Hoplolaimus indicus.

    PubMed

    Haque, M D; Mukhopadhyaya, M C

    1979-10-01

    Seedlings of Corchorus capsularis (cv. C4444) were inoculated with Meloidogyne incognita, Hoplolaimus indicus, and a fungus pathogen of jute, Macrophomina phaseoli, separately and in all possible combinations. The significant damage of jute plants caused individually by the pathogens was aggravated when the fungus was associated with either of the nematode species. M. incognita alone caused greater damage than either H. indicus or Macrophomina phaseoli alone. Plants inoculated with M. incognita and Macrophomina phaseoli were more severely damaged than plants inoculated with H. indicus and the fungus. Plant growth was minimum and disease symptoms were maximum when all pathogens acted together. In the presence of the fungus, M. incognita produced fewer galls. The reproduction of H. indicus was not influenced by the other organisms.

  5. Pathogenicity of Macrophomina phaseoli on Jute in the Presence of Meloidogyne incognita and Hoplolaimus indicus

    PubMed Central

    Haque, M. D. Samsul; Mukhopadhyaya, M. C.

    1979-01-01

    Seedlings of Corchorus capsularis (cv. C4444) were inoculated with Meloidogyne incognita, Hoplolaimus indicus, and a fungus pathogen of jute, Macrophomina phaseoli, separately and in all possible combinations. The significant damage of jute plants caused individually by the pathogens was aggravated when the fungus was associated with either of the nematode species. M. incognita alone caused greater damage than either H. indicus or Macrophomina phaseoli alone. Plants inoculated with M. incognita and Macrophomina phaseoli were more severely damaged than plants inoculated with H. indicus and the fungus. Plant growth was minimum and disease symptoms were maximum when all pathogens acted together. In the presence of the fungus, M. incognita produced fewer galls. The reproduction of H. indicus was not influenced by the other organisms. PMID:19300650

  6. Reproduction and Development of Meloidogyne incognita and M. javanica on Guardian Peach Rootstock

    PubMed Central

    Nyczepir, A. P.; Beckman, T. G.; Reighard, G. L.

    1999-01-01

    Guardian peach rootstock was evaluated for susceptibility to Meloidogyne incognita race 3 (Georgia-peach isolate) and M. javanica in the greenhouse. Both commercial Guardian seed sources produced plants that were poor hosts of M. incognita and M. javanica. Reproduction as measured by number of egg masses and eggs per plant, eggs per egg mass, and eggs per gram of root were a better measure of host resistance than number of root galls per plant. Penetration, development, and reproduction of M. incognita in Guardian (resistant) and Lovell (susceptible) peach were also studied in the greenhouse. Differences in susceptibility were not attributed to differential penetration by the infectivestage juveniles (J2) or the number of root galls per plant. Results indicated that M. incognita J2 penetrated Guardian roots and formed galls, but that the majority of the nematodes failed to mature and reproduce. PMID:19270905

  7. Development of a sweet cherry pepper line with resistance to the southern root-knot nematode Meloidogyne incognita

    USDA-ARS?s Scientific Manuscript database

    The southern root-knot nematode (Meloidogyne incognita) is a major pathogen of pepper (Capsicum spp.), causing significant yield losses in heavily infected plants. The N-gene confers resistance to M. incognita, and has been successfully used to mitigate nematode damage in specific pepper varieties f...

  8. Meloidogyne incognita emigration from cotton roots may be induced by the resistance QTL qMi-C11

    USDA-ARS?s Scientific Manuscript database

    Upland cotton (Gossypium hirsutum) is one of the most widely grown crops in the southern US, and Meloidogyne incognita is the most significant pathogen of cotton in the US. Two QTLs, qMi-C11 and qMi-C14, conferring resistance to M. incognita have been identified in cotton. Previous research docume...

  9. Management of Meloidogyne incognita with Jesup (Max-Q) tall fescue grass prior to peach orchard establishment

    USDA-ARS?s Scientific Manuscript database

    The effects of two preplant Jesup (Max-Q) tall fescue grass ground cover systems as alternatives to chemical control of Meloidogyne incognita were investigated from 2006-2013. Ground cover establishment was initiated in 2006, in a site known to be infested with M. incognita. Treatments included tw...

  10. Pathogenicity of Pratylenchus penetrans, Heterodera glycines, and Meloidogyne incognita on Soybean Genotypes

    PubMed Central

    Melakeberhan, Haddish

    1998-01-01

    The pathogenicity of Heterodera glycines, Meloidogyne incognita, and Pratylenchus penetrans on H. glycines-resistant 'Bryan,' tolerant-susceptible 'G88-20092,' and intolerant-susceptible 'Tracy M' soybean cultivars was tested using plants grown in 800 cm³ of soil in 15-cm-diam. clay pots in three greenhouse experiments. Plants were inoculated with 0, 1,000, 3,000, or 9,000 H. glycines race 3 or M. incognita eggs, or vermiform stages of P. penetrans/pot. Forty days after inoculation, nmnbers of all three nematodes, except H. glycines on Bryan, generally increased with increasing inoculum levels in Experiment I. Heterodera glycines and M. incognita significantly decreased growth only of Tracy M. At 45 and 57 days after inoculation with 6,000 individuals/pot in experiments II and III, respectively, significantly more P. penetrans and M. incognita than H. glycines were found on Bryan. However, H. glycines and M. incognita population densities were greater than P. penetrans on G88-20092 and Tracy M. Growth of Tracy M infected by H. glycines and M. incognita and growth of G88-20092 infected by M. incognita decreased in Experiment III. Pratylenchus penetrans did not affect plant growth. Reduction in plant growth differed according to the particular nematode species and cultivar, indicating that nematodes other than the species for which resistance is targeted can have different effects on cultivars of the same crop species. PMID:19274203

  11. Pathogenicity of Pratylenchus penetrans, Heterodera glycines, and Meloidogyne incognita on Soybean Genotypes.

    PubMed

    Melakeberhan, H

    1998-03-01

    The pathogenicity of Heterodera glycines, Meloidogyne incognita, and Pratylenchus penetrans on H. glycines-resistant 'Bryan,' tolerant-susceptible 'G88-20092,' and intolerant-susceptible 'Tracy M' soybean cultivars was tested using plants grown in 800 cm(3) of soil in 15-cm-diam. clay pots in three greenhouse experiments. Plants were inoculated with 0, 1,000, 3,000, or 9,000 H. glycines race 3 or M. incognita eggs, or vermiform stages of P. penetrans/pot. Forty days after inoculation, nmnbers of all three nematodes, except H. glycines on Bryan, generally increased with increasing inoculum levels in Experiment I. Heterodera glycines and M. incognita significantly decreased growth only of Tracy M. At 45 and 57 days after inoculation with 6,000 individuals/pot in experiments II and III, respectively, significantly more P. penetrans and M. incognita than H. glycines were found on Bryan. However, H. glycines and M. incognita population densities were greater than P. penetrans on G88-20092 and Tracy M. Growth of Tracy M infected by H. glycines and M. incognita and growth of G88-20092 infected by M. incognita decreased in Experiment III. Pratylenchus penetrans did not affect plant growth. Reduction in plant growth differed according to the particular nematode species and cultivar, indicating that nematodes other than the species for which resistance is targeted can have different effects on cultivars of the same crop species.

  12. Reproduction of Meloidogyne incognita and M. graminis on Several Grain Sorghum Hybrids.

    PubMed

    Hurd, Katherine; Faske, Travis R

    2017-06-01

    A total of 27 grain sorghum hybrids were evaluated in a series of greenhouse experiments to determine their susceptibility to Meloidogyne incognita race 3 and M. graminis. Each hybrid was inoculated with 2,000 nematode eggs/pot. Reproduction by M. incognita was numerically greater than M. graminis on 93% of the hybrids tested, indicating that grain sorghum is a better host for M. incognita than M. graminis. A wide variation in host suitability was observed on these hybrids in a second experiment as reproduction by M. incognita ranged from 395 to 3,818 eggs/g of root. Only two hybrids, Terral RV9782 and RV9823, consistently supported <20% reproduction by M. incognita compared to the most susceptible hybrid, Golden Acres 5556. Reproduction of four isolates of M. incognita was evaluated on six selected hybrids in a third greenhouse experiment. Hybrid susceptibility was similar to that observed in the previous experiment for all isolates. A difference in isolate aggressiveness was observed between two of the four isolates across all hybrids. In fields where damaging populations of M. incognita are present, most grain sorghum hybrids will likely maintain or increase the nematode population for the subsequent crop.

  13. Velvetbean (Mucuna pruriens) extracts: impact on Meloidogyne incognita survival and on Lycopersicon esculentum and Lactuca sativa germination and growth.

    PubMed

    Zasada, Inga A; Klassen, Waldemar; Meyer, Susan L F; Codallo, Maharanie; Abdul-Baki, Aref A

    2006-11-01

    Velvetbean (Mucuna spp.) is a summer annual that has been used as a cover crop to reduce erosion, fix nitrogen and suppress weeds and plant-parasitic nematodes. Crude aqueous extracts (1:15 dry weight plant/volume water) were made from velvetbean plant parts, and various concentrations of the extracts were evaluated in vitro for toxicities to different stages of Meloidogyne incognita (Kofoid and White) Chitwood and for suppression of hypocotyl and root growth and inhibition of germination of tomato (Lycopersicon esculentum L.) and lettuce (Lactuca sativa L.). Germination was only affected by the full-strength extract from leaf blades. Lettuce root growth was the most sensitive indicator of allelopathic activity of the plant part extracts. Lettuce and tomato root growth was more sensitive to the extract from main roots than to extracts of other plant parts, with lethal concentration (LC50) values of 1.2 and 1.1% respectively. Meloidogyne incognita egg hatch was less sensitive to extracts from velvetbean than the juvenile (J2) stage. There was no difference among LC50 values of the extracts from different plant parts against the egg stage. Based on LC50 values, the extract from fine roots was the least toxic to J2 (LC50 39.9%), and the extract from vines the most toxic (LC50 7.8%). The effects of the extracts were nematicidal because LC50 values did not change when the extracts were removed and replaced with water. Copyright (c) 2006 Society of Chemical Industry.

  14. Suitability of Zucchini and Cucumber Genotypes to Populations of Meloidogyne arenaria, M. incognita, and M. javanica

    PubMed Central

    López-Gómez, Manuel; Flor-Peregrín, Elena; Talavera, Miguel; Verdejo-Lucas, Soledad

    2015-01-01

    The host suitability of five zucchini and three cucumber genotypes to Meloidogyne incognita (MiPM26) and M. javanica (Mj05) was determined in pot experiments in a greenhouse. The number of egg masses (EM) did not differ among the genotypes of zucchini or cucumber, but the eggs/plant and reproduction factor (Rf) did slightly. M. incognita MiPM26 showed lower EM, eggs/plant, and Rf than M. javanica Mj05. Examination of the zucchini galls for nematode postinfection development revealed unsuitable conditions for M. incognita MiPM26 as only 22% of the females produced EM compared to 95% of the M. javanica females. As far as cucumber was concerned, 86% of the M. incognita and 99% of the M. javanica females produced EM, respectively. In a second type of experiments, several populations of M. arenaria, M. incognita, and M. javanica were tested on zucchini cv. Amalthee and cucumber cv. Dasher II to assess the parasitic variation among species and populations of Meloidogyne. A greater parasitic variation was observed in zucchini than cucumber. Zucchini responded as a poor host for M. incognita MiPM26, MiAL09, and MiAL48, but as a good host for MiAL10 and MiAL15. Intraspecific variation was not observed among the M. javanica or M. arenaria populations. Cucumber was a good host for all the tested populations. Overall, both cucurbits were suitable hosts for Meloidogyne but zucchini was a poorer host than the cucumber. PMID:25861120

  15. Suitability of Zucchini and Cucumber Genotypes to Populations of Meloidogyne arenaria, M. incognita, and M. javanica.

    PubMed

    López-Gómez, Manuel; Flor-Peregrín, Elena; Talavera, Miguel; Verdejo-Lucas, Soledad

    2015-03-01

    The host suitability of five zucchini and three cucumber genotypes to Meloidogyne incognita (MiPM26) and M. javanica (Mj05) was determined in pot experiments in a greenhouse. The number of egg masses (EM) did not differ among the genotypes of zucchini or cucumber, but the eggs/plant and reproduction factor (Rf) did slightly. M. incognita MiPM26 showed lower EM, eggs/plant, and Rf than M. javanica Mj05. Examination of the zucchini galls for nematode postinfection development revealed unsuitable conditions for M. incognita MiPM26 as only 22% of the females produced EM compared to 95% of the M. javanica females. As far as cucumber was concerned, 86% of the M. incognita and 99% of the M. javanica females produced EM, respectively. In a second type of experiments, several populations of M. arenaria, M. incognita, and M. javanica were tested on zucchini cv. Amalthee and cucumber cv. Dasher II to assess the parasitic variation among species and populations of Meloidogyne. A greater parasitic variation was observed in zucchini than cucumber. Zucchini responded as a poor host for M. incognita MiPM26, MiAL09, and MiAL48, but as a good host for MiAL10 and MiAL15. Intraspecific variation was not observed among the M. javanica or M. arenaria populations. Cucumber was a good host for all the tested populations. Overall, both cucurbits were suitable hosts for Meloidogyne but zucchini was a poorer host than the cucumber.

  16. Effects of 1,3-Dicliloropropene for Meloidogyne incognita Management on Cotton Produced under Furrow Irrigation

    PubMed Central

    Thomas, S. H.; Smith, D. W.

    1993-01-01

    Field trials were conducted during 1990 to evaluate the effects of preplant soil fumigation with 1,3-dichloropropene (1,3-D) on yield and fiber quality of furrow-irrigated cotton cultivars subjected to high population densities of Meloidogyne incognita. We measured the responses of eight upland cotton cultivars with different levels of root-knot nematode resistance and compared the responses of upland and Pima cottons. Reductions in lint weight ranged from 10 to 52% among cultivars grown in soil without 1,3-D fumigation compared with those grown in treated soil. Meloidogyne incognita reduced yields primarily by reducing the number of bolls on each plant, rather than by decreasing boll size. Cotton fiber quality varied among cultivars but was unaffected by M. incognita in either study. Upland cotton cultivar Acala 1517-88 and M-315/240 sustained less than half the yield reductions observed with M. incognita-susceptible cultivars Deltapine 41 and Paymaster 145. Sixty days after cotton emergence, fewer M. incognita second-stage juveniles were recovered from M-315/240 than all other cultivars. PMID:19279835

  17. Influence of Low Temperature on Development of Meloidogyne incognita and M. hapla Eggs in Egg Masses

    PubMed Central

    Vrain, T. C.; Barker, K. R.

    1978-01-01

    Egg masses of Meloidogyne incognita and M. hapla were placed in soil at 10, 12, 16, and 20 C. At regular intervals, eggs from samples of egg masses were released from the gelatinous matrices and their developmental stages recorded. The number of days necessary to complete each stage from gastrulation to hatch is given for each temperature. The minimal temperature threshold for the development of eggs was computed by linear regression to be 8.26 C for M. incognita and 6.74 C for M. hapla. PMID:19305859

  18. Integrated management of root-knot nematode, Meloidogyne incognita infestation in tomato and grapevine.

    PubMed

    Kumari, N Swarna; Sivakumar, C V

    2005-01-01

    An integrated approach with the obligate bacterial parasite, Pasteuria penetrans and nematicides was assessed for the management of the root-knot nematode, Meloidogyne incognita infestation in tomato and grapevine. Seedlings of tomato cv. Co3 were transplanted into pots filled with sterilized soil and inoculated with nematodes (5000 juveniles/pot). The root powder of P. penetrans at 10 mg/pot was applied alone and in combination with carbofuran at 6 mg/pot. Application of P. penetrans along with carbofuran recorded lowest nematode infestation (107 nematodes/200 g soil) compared to control (325 nematodes/200 g soil). The rate of parasitization was 83.1% in the carbofuran and P. penetrans combination treatment as against 61.0% in the P. penetrans treatment only. The plant growth was also higher in the combination treatment compared to all other treatments. A field trial was carried out to assess the efficacy of P. penetrans and nematicides viz., carbofuran and phorate in the management of root-knot nematode, M. incognita infestation of grapevine cv. Muscat Hamburg. A nematode and P. penetrans infested grapevine field was selected and treatments either with carbofuran or phorate at 1 g a.i/vine was given. The observations were recorded at monthly interval. The results showed that the soil nematode population was reduced in nematicide treated plots. Suppression of nematodes was higher under phorate (117 nematodes/200 g soil) than under carbofuran (126.7 nematodes/200 g soil) treatment. The number of juveniles parasitized was also influenced by nematicides and spore load carried/juvenile with phorate being superior and the increase being 17.0 and 29.0% respectively over the control. The results of these experiment confirmed the compatibility of P. penetrans with nematicides and its biological control potential against the root-knot nematode.

  19. Biological Control of Meloidogyne incognita by Aspergillus niger F22 Producing Oxalic Acid

    PubMed Central

    Jang, Ja Yeong; Choi, Yong Ho; Shin, Teak Soo; Kim, Tae Hoon; Shin, Kee-Sun; Park, Hae Woong; Kim, Young Ho; Kim, Hun; Choi, Gyung Ja; Jang, Kyoung Soo; Cha, Byeongjin; Kim, In Seon; Myung, Eul Jae

    2016-01-01

    Restricted usage of chemical nematicides has led to development of environmentally safe alternatives. A culture filtrate of Aspergillus niger F22 was highly active against Meloidogyne incognita with marked mortality of second-stage juveniles (J2s) and inhibition of egg hatching. The nematicidal component was identified as oxalic acid by organic acid analysis and gas chromatography-mass spectroscopy (GC-MS). Exposure to 2 mmol/L oxalic acid resulted in 100% juvenile mortality at 1 day after treatment and suppressed egg hatching by 95.6% at 7 days after treatment. Oxalic acid showed similar nematicidal activity against M. hapla, but was not highly toxic to Bursaphelenchus xylophilus. The fungus was incubated on solid medium and dried culture was used for preparation of a wettable powder-type (WP) formulation as an active ingredient. Two WP formulations, F22-WP10 (ai 10%) and oxalic acid-WP8 (ai 8%), were prepared using F22 solid culture and oxalic acid. In a field naturally infested with M. incognita, application of a mixture of F22-WP10 + oxalic acid-WP8 at 1,000- and 500-fold dilutions significantly reduced gall formation on the roots of watermelon plants by 58.8 and 70.7%, respectively, compared to the non-treated control. The disease control efficacy of the mixture of F22-WP10 + oxalic acid-WP8 was significantly higher than that of a chemical nematicide, Sunchungtan (ai 30% fosthiazate). These results suggest that A. niger F22 can be used as a microbial nematicide for the control of root-knot nematode disease. PMID:27258452

  20. Biological Control of Meloidogyne incognita by Aspergillus niger F22 Producing Oxalic Acid.

    PubMed

    Jang, Ja Yeong; Choi, Yong Ho; Shin, Teak Soo; Kim, Tae Hoon; Shin, Kee-Sun; Park, Hae Woong; Kim, Young Ho; Kim, Hun; Choi, Gyung Ja; Jang, Kyoung Soo; Cha, Byeongjin; Kim, In Seon; Myung, Eul Jae; Kim, Jin-Cheol

    2016-01-01

    Restricted usage of chemical nematicides has led to development of environmentally safe alternatives. A culture filtrate of Aspergillus niger F22 was highly active against Meloidogyne incognita with marked mortality of second-stage juveniles (J2s) and inhibition of egg hatching. The nematicidal component was identified as oxalic acid by organic acid analysis and gas chromatography-mass spectroscopy (GC-MS). Exposure to 2 mmol/L oxalic acid resulted in 100% juvenile mortality at 1 day after treatment and suppressed egg hatching by 95.6% at 7 days after treatment. Oxalic acid showed similar nematicidal activity against M. hapla, but was not highly toxic to Bursaphelenchus xylophilus. The fungus was incubated on solid medium and dried culture was used for preparation of a wettable powder-type (WP) formulation as an active ingredient. Two WP formulations, F22-WP10 (ai 10%) and oxalic acid-WP8 (ai 8%), were prepared using F22 solid culture and oxalic acid. In a field naturally infested with M. incognita, application of a mixture of F22-WP10 + oxalic acid-WP8 at 1,000- and 500-fold dilutions significantly reduced gall formation on the roots of watermelon plants by 58.8 and 70.7%, respectively, compared to the non-treated control. The disease control efficacy of the mixture of F22-WP10 + oxalic acid-WP8 was significantly higher than that of a chemical nematicide, Sunchungtan (ai 30% fosthiazate). These results suggest that A. niger F22 can be used as a microbial nematicide for the control of root-knot nematode disease.

  1. Bacillus cereus strain S2 shows high nematicidal activity against Meloidogyne incognita by producing sphingosine

    PubMed Central

    Gao, Huijuan; Qi, Gaofu; Yin, Rong; Zhang, Hongchun; Li, Chenggang; Zhao, Xiuyun

    2016-01-01

    Plant-parasitic nematodes cause serious crop losses worldwidely. This study intended to discover the antagonistic mechanism of Bacillus cereus strain S2 against Meloidogyne incognita. Treatment with B. cereus strain S2 resulted in a mortality of 77.89% to Caenorhabditis elegans (a model organism) and 90.96% to M. incognita. In pot experiment, control efficiency of B. cereus S2 culture or supernatants were 81.36% and 67.42% towards M. incognita, respectively. In field experiment, control efficiency was 58.97% towards M. incognita. Nematicidal substances were isolated from culture supernatant of B. cereus S2 by polarity gradient extraction, silica gel column chromatography and HPLC. Two nematicidal compounds were identified as C16 sphingosine and phytosphingosine by LC-MS. The median lethal concentration of sphingosine was determined as 0.64 μg/ml. Sphingosine could obviously inhibit reproduction of C. elegans, with an inhibition rate of 42.72% for 24 h. After treatment with sphingosine, ROS was induced in intestinal tract, and genital area disappeared in nematode. Furthermore, B. cereus S2 could induce systemic resistance in tomato, and enhance activity of defense-related enzymes for biocontrol of M. incognita. This study demonstrates the nematicidal activity of B. cereus and its product sphingosine, as well provides a possibility for biocontrol of M. incognita. PMID:27338781

  2. Differential effects on nematode development of two QTLs for resistance to Meloidogyne incognita in cotton

    USDA-ARS?s Scientific Manuscript database

    QTLs qMi-C11 and qMi-C14 impart resistance to Meloidogyne incognita in cotton. Breeders had backcrossed both QTLs into Coker 201 (C201; susceptible) to create M-120 RNR (M-120; highly resistant), and we crossed C201 and M-120 to create near isogenic lines with either qMi-C11 or qMi-C14. Previous wor...

  3. Coupling of MIC-3 overexpression with the chromosome 11 and 14 root-knot nematode (RKN) (Meloidogyne incognita) resistance QTLs provides insights into the regulation of the RKN resistance response in Upland cotton...

    USDA-ARS?s Scientific Manuscript database

    High levels of resistance to root-knot nematode (RKN) (Meloidogyne incognita) in Upland cotton (Gossypium hirsutum) is mediated by two major quantitative trait loci (QTL) located on chromosomes 11 and 14. We had previously determined that MIC-3 expression played a direct role in suppressing RKN egg...

  4. Genetic Basis of the Epidemiologic effects of Resistance to Meloidogyne incognita in the Tomato Cultivar Small Fry

    PubMed Central

    Bost, S. C.; Triantaphyllou, A. C.

    1982-01-01

    The genetic nature of resistance and its epidemiologic effects on two Meloidogyne incognita populations were assessed in the F₁ hybrid tomato cv. Small Fry. The progeny of a Small Fry × Small Fry cross segregated in a 3:1 resistant:susceptible ratio, indicating the presence of a single, completely dominant resistance gene (LMiR₂) in Small Fry. In a subsequent experiment, infection frequency and the rate of development of primary infection on resistant Small Fry × Small Fry segregates were compared to those on susceptible segregates and the susceptible cultivar Rutgers. Suppression in both infection frequency and rate of development of primary infection was entirely attributable to gene LMiR₂. A single egg-mass population of M. incognita propagated for 12 generations on Small Fry showed an increased ability over the wild type population to parasitize plants containing the LMiR₂ gene but failed to completely overcome resistance. The relationship of this phenomenon to the genetics of the Lycopersicon esculentum-M. incognita interaction is discussed. PMID:19295750

  5. Management of root-knot nematode, Meloidogyne incognita in carrot.

    PubMed

    Pedroche, Nordalyn B; Villanueva, Luciana M; De Waele, Dirk

    2009-01-01

    The root-knot nematode, Meloidogyne incognito, remains to be one of the most important constraints in agricultural production worldwide. However, reports showed that root-knot nematode (RKN) population can be suppressed by addition of organic amendments. A greenhouse microplot experiment was conducted to determine if locally available organic amendments would reduce RKN population and improve the growth and yield of more susceptible and less susceptible carrot cultivars in comparison with the farmers' practice. Residues of broccoli, chicken manure and Trichoderma inoculant were incorporated into the soil artificially infested with root-knot nematodes. Untreated microplots were provided as controls. Three months after transplanting, nematodes were recovered from the soil using the modified Baermann-tray technique and from the roots using staining technique. The number of root-knot nematodes was counted under the stereoscopic microscope. In the more susceptible cultivar New Kuroda, significantly lowest number of second stage juveniles (J2's) was recovered from the soil incorporated with broccoli left-over materials and Trichoderma inoculant while chicken manure-amended soil had the most number of J2's. Galls and egg masses in secondary roots were highest in unamended-inoculated soil which was significantly different from broccoli-amended soil with solarisation and Trichoderma inoculant. No significant differences were obtained among the treatments in the less susceptible cultivar Chunhong. The yield was significantly highest in broccoli-amended soil with solarisation and Trichoderma inoculant but no significant difference existed between the two cultivars tested. In general, the treatments with broccoli residues and Trichoderma inoculant were able to decrease root-knot nematode population and significantly increase the yield relative to untreated soil, however, differences between the two cultivars were not significant.

  6. Virulence of Meloidogyne incognita to expression of N gene in pepper

    PubMed Central

    2011-01-01

    Four pepper genotypes classified as resistant and four pepper genotypes classified as susceptible to several avirulent populations of M. incognita were compared for their reactions against a population of Meloidogyne incognita (Chitwood) Kofoid and White which had been shown to be virulent to resistant bell pepper (Capsicum annuum) in preliminary tests. The virulent population of M. incognita originated from a commercial bell pepper field in California. The resistant pepper genotypes used in all experiments were the Capsicum annuum cultivars Charleston Belle, Carolina Wonder, and Carolina Cayenne, and the C. chinense cultigen PA-426. The susceptible pepper genotypes used in the experiments were the C. annuum cultivars Keystone Resistant Giant, Yolo Wonder B, California Wonder, and the C. chinense cultigen PA-350. Root gall indices (GI) were ≥ 3.0 for all genotypes in both tests except for PA-426 (GI=2.57) in test 1 and ‘Carolina Cayenne’ (GI=2.83) in test 2. Numbers of eggs per gram fresh root weight ranged from 20,635 to 141,319 and reproductive indices ranged from 1.20 to 27.2 for the pepper genotypes in both tests, indicating that all eight pepper genotypes tested were susceptible to the M. incognita population used in these tests. The M. incognita population used in these studies overcame resistance conferred by the N gene in all resistant genotypes of both C. annuum and C. chinense. PMID:22791917

  7. Virulence of Meloidogyne incognita to expression of N gene in pepper.

    PubMed

    Thies, Judy A

    2011-06-01

    Four pepper genotypes classified as resistant and four pepper genotypes classified as susceptible to several avirulent populations of M. incognita were compared for their reactions against a population of Meloidogyne incognita (Chitwood) Kofoid and White which had been shown to be virulent to resistant bell pepper (Capsicum annuum) in preliminary tests. The virulent population of M. incognita originated from a commercial bell pepper field in California. The resistant pepper genotypes used in all experiments were the Capsicum annuum cultivars Charleston Belle, Carolina Wonder, and Carolina Cayenne, and the C. chinense cultigen PA-426. The susceptible pepper genotypes used in the experiments were the C. annuum cultivars Keystone Resistant Giant, Yolo Wonder B, California Wonder, and the C. chinense cultigen PA-350. Root gall indices (GI) were ≥ 3.0 for all genotypes in both tests except for PA-426 (GI=2.57) in test 1 and 'Carolina Cayenne' (GI=2.83) in test 2. Numbers of eggs per gram fresh root weight ranged from 20,635 to 141,319 and reproductive indices ranged from 1.20 to 27.2 for the pepper genotypes in both tests, indicating that all eight pepper genotypes tested were susceptible to the M. incognita population used in these tests. The M. incognita population used in these studies overcame resistance conferred by the N gene in all resistant genotypes of both C. annuum and C. chinense.

  8. Associated bacteria of different life stages of Meloidogyne incognita using pyrosequencing-based analysis.

    PubMed

    Cao, Yi; Tian, Baoyu; Ji, Xinglai; Shang, Shenghua; Lu, Chaojun; Zhang, Keqin

    2015-08-01

    The root knot nematode (RKN), Meloidogyne incognita, belongs to the most damaging plant pathogens worldwide, and is able to infect almost all cultivated plants, like tomato. Recent research supports the hypothesis that bacteria often associated with plant-parasitic nematodes, function as nematode parasites, symbionts, or commensal organisms etc. In this study, we explored the bacterial consortia associated with M. incognita at different developmental stages, including egg mass, adult female and second-stage juvenile using the pyrosequencing approach. The results showed that Proteobacteria, with a proportion of 71-84%, is the most abundant phylum associated with M. incognita in infected tomato roots, followed by Actinobacteria, Bacteroidetes, Firmicutes etc. Egg mass, female and second-stage juvenile of M. incognita harbored a core microbiome with minor difference in communities and diversities. Several bacteria genera identified in M. incognita are recognized cellulosic microorganisms, pathogenic bacteria, nitrogen-fixing bacteria and antagonists to M. incognita. Some genera previously identified in other plant-parasitic nematodes were also found in tomato RKNs. The potential biological control microorganisms, including the known bacterial pathogens and nematode antagonists, such as Actinomycetes and Pseudomonas, showed the largest diversity and proportion in egg mass, and dramatically decreased in second-stage juvenile and female of M. incognita. This is the first comprehensive report of bacterial flora associated with the RKN identified by pyrosequencing-based analysis. The results provide valuable information for understanding nematode-microbiota interactions and may be helpful in the development of novel nematode-control strategies. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Mining novel effector proteins from the esophageal gland cells of Meloidogyne incognita

    PubMed Central

    Rutter, William B.; Hewezi, Tarek; Abubucker, Sahar; Maier, Tom R.; Huang, Guozhong; Mitreva, Makedonka; Hussey, Richard S.; Baum, Thomas J.

    2014-01-01

    Meloidogyne incognita is one of the most economically damaging plant pathogens in agriculture and horticulture. Identifying and characterizing the effector proteins, which M. incognita secretes into its host plants during infection, is an important step towards finding new ways to manage this pest. In this study we have identified the cDNAs for 18 putative effectors, i.e., proteins that have the potential to facilitate M. incognita parasitism of host plants. These putative effectors are secretory proteins that do not contain transmembrane domains and whose genes are specifically expressed in the secretory gland cells of the nematode, indicating that they are likely secreted from the nematode through its stylet. We have determined that in the plant cells, these putative effectors are likely to localize to the cytoplasm. Furthermore, the transcripts of many of these novel effectors are specifically up-regulated during different stages of the nematode’s life cycle, indicating that they function at specific stages during M. incognita parasitism. The predicted proteins showed little to no homology to known proteins from free-living nematode species, suggesting that they evolved recently to support the parasitic lifestyle. On the other hand, several of the effectors are part of gene families within the M. incognita genome as well as that of Meloidogyne hapla, which points to an important role that these putative effectors are playing in both parasites. With the discovery of these putative effectors we have increased our knowledge of the effector repertoire utilized by root-knot nematodes to infect, feed, and reproduce on their host plants. Future studies investigating the roles these proteins play in planta will help mitigate the effects of this damaging pest. PMID:24875667

  10. Mitochondrial DNA Sequence Divergence among Meloidogyne incognita, Romanomermis culicivorax, Ascaris suum, and Caenorhabditis elegans

    PubMed Central

    Powers, T. O.; Harris, T. S.; Hyman, B. C.

    1993-01-01

    Mitochondrial DNA sequences were obtained from the NADH dehydrogenase subunit 3 (ND3), large rRNA, and cytochrome b genes from Meloidogyne incognita and Romanomermis culicivorax. Both species show considerable genetic distance within these same genes when compared with Caenorhabditis elegans or Ascaris suum, two species previously analyzed. Caenorhabditis, Ascaris, and Meloidogyne were selected as representatives of three subclasses in the nematode class Secernentea: Rhabditia, Spiruria, and Diplogasteria, respectively. Romanomermis served as a representative out-group of the class Adenophorea. The divergence between the phytoparasitic lineage (represented by Meloidogyne) and the three other species is so great that virtually every variable position in these genes appears to have accumulated multiple mutations, obscuring the phylogenetic information obtainable from these comparisons. The 39 and 42% amino acid similarity between the M. incognita and C. elegans ND3 and cytochrome b coding sequences, respectively, are approximately the same as those of C. elegans-mouse comparisons for the same genes (26 and 44%). This discovery calls into question the feasibility of employing cloned C. elegans probes as reagents to isolate phytoparasitic nematode genes. The genetic distance between the phytoparasitic nematode lineage and C. elegans markedly contrasts with the 79% amino acid similarity between C. elegans and A. suum for the same sequences. The molecular data suggest that Caenorhabditis and Ascaris belong to the same subclass. PMID:19279810

  11. Relationship of Aerial Broad Band Reflectance to Meloidogyne incognita Density in Cotton

    PubMed Central

    Wheeler, T. A.; Kaufman, H. W.

    2003-01-01

    Aerial images were obtained on 22 July 1999 and 4 August 2000 from five cotton sites infested with Meloidogyne incognita. Images contained three broad bands representing the green (500-600 nm), red (600-700 nm), and near-infrared (700-900 nm) spectrum. Soil samples were collected and assayed for nematodes in the fall at these sites. Sampling locations were identified from images, by locating the coordinates of a wide range of light intensity (measured as a digital number) for each single band, and combinations of bands. There was no single band or band combination in which reflectance consistently predicted M. incognita density. In all 10 site-year combinations, the minimum number of samples necessary to estimate M. incognita density within 25% of the population mean was greater when sampling by reflectance-based classes (3 to 4 per site) than sampling based on the entire site as one unit. Two sites were sampled at multiple times during the growing season. At these sites, there was no single time during the growing season optimal to take images for nematode sampling. Aerial infrared photography conducted during the growing season could not be used to accurately determine fall population densities of M. incognita. PMID:19265974

  12. Responses of Meloidogyne arenaria and M. incognita to Green Manures and Supplemental Urea in Glasshouse Culture

    PubMed Central

    Crow, W. T.; Guertal, E. A.; Rodríguez-Kábana, R.

    1996-01-01

    The recent loss of many effective nematicides has led to renewed interest in alternative methods of nematode management. Greenhouse experiments were conducted to determine the effects of rapeseed and velvetbean green manures, and supplemental urea, on the root-knot nematodes Meloidogyne arenaria and M. incognita. Green manures were incorporated with M. arenaria-infested soil using rates totaling 200,300, and 400 mg N/kg soil. Squash plants grown in this soil were evaluated using a gall index and plant dry weight. A second experiment tested ratios of rapeseed green manure to urea resulting in rates of 50, 100, and 150 mg N/kg soil on viability ofM. incognita eggs and degree of galling on squash test plants. A third experiment examined combinations of velvetbean green manure and urea resulting in rates of 100, 200, and 300 mg N/kg soil on viability of M. incognita eggs. When applied at rates of 200, 300, and 400 mg N/kg soil, rapeseed green manure was more effective than velvetbean green manure at reducing galling of squash roots caused by M. arenaria. Decreased viability of M. incognita eggs was observed from treatments that received rates ≥ 1200 mg N/kg soil with higher percentages of N from urea. PMID:19277190

  13. Penetration, Post-penetration Development, and Reproduction of Meloidogyne incognita on Cucumis melo var. texanus.

    PubMed

    Faske, T R

    2013-03-01

    Cucumis melo var. texanus, a wild melon commonly found in the southern United States and two accessions, Burleson Co. and MX 1230, expressed resistance to Meloidogyne incognita in preliminary experiments. To characterize the mechanism of resistance, we evaluated root penetration, post-penetration development, reproduction, and emigration of M. incognita on these two accessions of C. melo var. texanus. Additionally, we evaluated 22 accessions of C. melo var. texanus for their reaction against M. incognita in a greenhouse experiment. Fewer (P ≤ 0.05) J2 penetrated the root system of C. melo var. texanus accessions (Burleson Co. and MX 1230) and C. metuliferus (PI 482452) (resistant control), 7 days after inoculation (DAI) than in C. melo 'Hales Best Jumbo' (susceptible control). A delayed (P ≤ 0.05) rate of nematode development was observed at 7, 14, and 21 DAI that contributed to lower (P ≤ 0.05) egg production on both accessions and C. metuliferus compared with C. melo. Though J2 emigration was observed on all Cucumis genotypes a higher (P ≤ 0.05) rate of J2 emigration was observed from 3 to 6 DAI on accession Burleson Co. and C. metuliferus than on C. melo. The 22 accessions of C. melo var. texanus varied relative to their reaction to M. incognita with eight supporting similar levels of nematode reproduction to that of C. metuliferus. Cucumis melo var. texanus may be a useful source of resistance against root-knot nematode in melon.

  14. Influence of Low Temperature on Rate of Development of Meloidogyne incognita and M. hapla Larvae

    PubMed Central

    Vrain, T. C.; Barker, K. R.; Holtzman, G. I.

    1978-01-01

    Development of Meloidogyne incognita and M. hapla larvae in clover roots was studied at 20, 16, 12, and 8 C in growth chambers and in the field from fall through spring, in North Carolina. Larvae of both species invaded roots and developed at 20, 16, and 12 C, but not at 8 C. The time necessary to complete the larval stages at each temperature was determined. The minimal temperature for development of M. incognita larvae was 10.08 C and 8.8 C for M. hapla larvae. In the field, soil temperature at 10 cm deep was favorable for development of larvae until the end of November, and again from February on. All stages of the nematodes survived freezing temperatures in the roots. Reproduction of both species was evident in March or Apri1 after inoculation and accumulation of 8,500 to 11,250 degree-hours. PMID:19305832

  15. Population Dynamics of Meloidogyne incognita on Corn Grown in Soil in Fested with Arthrobotrys conoides

    PubMed Central

    Al-Hazmi, A. S.; Schmitt, D. P.; Sasser, J. N.

    1982-01-01

    Microplot and greenhouse experiments were conducted to evaluate the effects of soil incorporation of the nematophagous fungus Arthrobotrys conoides and green alfalfa mulch on the population dynamics of Meloidogyne incognita on corn. Reproduction of M. incognita and the incidence of root galling were reduced by the addition of A. conoides and/or green alfalfa in all tests. Numbers of juveniles were reduced by as much as 84%, and eggs were fewest in early to mid-season soil samples from microplots. Yields increased in treatments with A. conoides and/or green alfalfa in greenhouse tests and in the microplot tests in 1979. No interaction was found between the fungus and green alfalfa in the reduction of the nematode population. PMID:19295673

  16. Varietal Response of Tomato to the Interaction of Salinity and Meloidogyne incognita Infection

    PubMed Central

    Edongali, Ezarug A.; Ferris, Howard

    1982-01-01

    Response of tomato (Lycopersicon esculentum) cultivars to a range of conductivity levels was tested in the presence and absence of Meloidogyne incognita. The conductivity levels were produced by appropriate adjustment of a 1:1 solution of sodium chloride and calcium chloride. The growth of M. incognita resistant ('Beefmaster' and 'Atkinson') and susceptible ('Hunts 2580' and 'Ronita') tomato plants was inversely related to soil salinity between ECe 0 and 5 mmhos/cm. Nematode inoculation of salt-stressed plants significantly reduced plant height, fresh and dry weight, number of flowers, and fruit weight in most cultivars. In Hunts 2580, flower number and fruit weight increased; apparently flower production shifted from determinate to indeterminate, with negative implications for mechanical harvesting. Nematode reproduction on susceptible varieties also decreased with increase in salinity. PMID:19295675

  17. Comparative efficacy of different approaches to managing Meloidogyne incognita on green bean.

    PubMed

    Al-Hazmi, Ahmad S; Dawabah, Ahmed A M; Al-Nadhari, Saleh N; Al-Yahya, Fahad A

    2017-01-01

    A greenhouse study was conducted to compare the relative efficacy of different approaches to managing Meloidogyne incognita on green bean. These approaches included chemical (fumigant, non-fumigant, seed dressing, and seed dip), biological (the egg-parasitic fungus, Paecilomyces lilacinus and the mycorrhizal fungus Glomus sp.), physical (soil solarization), and cultural (chicken litter and urea) methods. Accordingly, nine different control materials and application methods plus nematode-infected and non-infected controls were compared. Two important parameters were considered: plant response (plant growth and root galling) and nematode reproduction (production of eggs and the reproduction factor Rf). The results showed that the use of chicken litter as an organic fertilizer severely affected the growth and survival of the plants. Therefore, this treatment was removed from the evaluation test. All of the other eight treatments were found to be effective against nematode reproduction, but with different levels of efficacy. The eight treatments decreased (38.9-99.8%) root galling, increased plant growth and suppressed nematode reproduction. Based on three important criteria, namely, gall index (GI), egg mass index (EMI), and nematode reproduction factor (RF), the tested materials and methods were categorized into three groups according to their relative control efficacy under the applied test conditions. The three groups were as follows: (1) the relatively high effective group (GI = 1.0-1.4, Rf = 0.07-0.01), which included the fumigant dazomet, the non-fumigant fenamiphos, soil solarization, and seed dip with fenamiphos; (2) the relatively moderate effective group (GI = 3.4-4.0, Rf = 0.24-0.60), which included seed dressing with fenamiphos and urea; and (3) the relatively less effective group (GI = 5.0, Rf = 32.2-37.2), which included P. lilacinus and Glomus sp.

  18. A Method for Field Infestation with Meloidogyne incognita

    PubMed Central

    Xing, L. J.; Westphal, A.

    2005-01-01

    A field inoculation method was developed to produce Meloidogyne spp. infestation sites with minimal quantities of nematode inoculum and with a reduced labor requirement compared to previous techniques. In a preseason-methyl bromidefumigated site, nematode egg suspensions were delivered at concentrations of 0 or 10x eggs/m of row where x = 2.12, 2.82, 3.52, or 4.22 through a drip line attached to the seed firmer of a commercial 2-row planter into the open seed furrow while planting cowpea. These treatments were compared to a hand-inoculated treatment, in which 103.1 eggs were delivered every 30 cm in 5 ml of water agar suspension 2 weeks after planting. Ten weeks after planting, infection of cowpea roots was measured by gall rating and gall counts on cowpea roots. A linear relationship between the inoculation levels and nematode-induced galls was found. At this time, the amount of galling per root system in the hand-inoculated treatment was less than in the machine-applied treatments. Advantages of this new technique include application uniformity and low population level requisite for establishing the nematode. This method has potential in field-testing of Meloidogyne spp. management strategies by providing uniform infestation of test sites at planting time. PMID:19262898

  19. Reproduction of Meloidogyne incognita Race 3 on Flue-cured Tobacco Homozygous for Rk1 and/or Rk2 Resistance Genes

    PubMed Central

    Pollok, Jill R.; Johnson, Charles S.; Eisenback, J. D.; Reed, T. David

    2016-01-01

    Most commercial tobacco cultivars possess the Rk1 resistance gene to races 1 and 3 of Meloidogyne incognita and race 1 of Meloidogyne arenaria, which has caused a shift in population prevalence in Virginia tobacco fields toward other species and races. A number of cultivars now also possess the Rk2 gene for root-knot resistance. Experiments were conducted in 2013 to 2014 to examine whether possessing both Rk1 and Rk2 increases resistance to a variant of M. incognita race 3 compared to either gene alone. Greenhouse trials were arranged in a completely randomized design with Coker 371-Gold (C371G; susceptible), NC 95 and SC 72 (Rk1Rk1), T-15-1-1 (Rk2Rk2), and STNCB-2-28 and NOD 8 (Rk1Rk1 and Rk2Rk2). Each plant was inoculated with 5,000 root-knot nematode eggs; data were collected 60 d postinoculation. Percent galling and numbers of egg masses and eggs were counted, the latter being used to calculate the reproductive index on each host. Despite variability, entries with both Rk1 and Rk2 conferred greater resistance to a variant of M. incognita race 3 than plants with Rk1 or Rk2 alone. Entries with Rk1 alone were successful in reducing root galling and nematode reproduction compared to the susceptible control. Entry T-15-1-1 did not reduce galling compared to the susceptible control but often suppressed reproduction. PMID:27418700

  20. Mining novel effector proteins from the esophageal gland cells of Meloidogyne incognita.

    PubMed

    Rutter, William B; Hewezi, Tarek; Abubucker, Sahar; Maier, Tom R; Huang, Guozhong; Mitreva, Makedonka; Hussey, Richard S; Baum, Thomas J

    2014-09-01

    Meloidogyne incognita is one of the most economically damaging plant pathogens in agriculture and horticulture. Identifying and characterizing the effector proteins which M. incognita secretes into its host plants during infection is an important step toward finding new ways to manage this pest. In this study, we have identified the cDNAs for 18 putative effectors (i.e., proteins that have the potential to facilitate M. incognita parasitism of host plants). These putative effectors are secretory proteins that do not contain transmembrane domains and whose genes are specifically expressed in the secretory gland cells of the nematode, indicating that they are likely secreted from the nematode through its stylet. We have determined that, in the plant cells, these putative effectors are likely to localize to the cytoplasm. Furthermore, the transcripts of many of these novel effectors are specifically upregulated during different stages of the nematode's life cycle, indicating that they function at specific stages during M. incognita parasitism. The predicted proteins showed little to no homology to known proteins from free-living nematode species, suggesting that they evolved recently to support the parasitic lifestyle. On the other hand, several of the effectors are part of gene families within the M. incognita genome as well as that of M. hapla, which points to an important role that these putative effectors are playing in both parasites. With the discovery of these putative effectors, we have increased our knowledge of the effector repertoire utilized by root-knot nematodes to infect, feed on, and reproduce on their host plants. Future studies investigating the roles that these proteins play in planta will help mitigate the effects of this damaging pest.

  1. Parasitic nematode Meloidogyne incognita interactions with different Capsicum annum cultivars reveal the chemical constituents modulating root herbiovry

    USDA-ARS?s Scientific Manuscript database

    Plant volatile signatures are often used as cues by herbivores to locate their preferred hosts. Here, we report on the volatile organic compounds used by the subterranean root-knot nematode (RKN) Meloidogyne incognita for host location. We compared responses of infective second stage juveniles (J2s)...

  2. Genetic and Physical Mapping of Meloidogyne Incognita Resistance on Chromosome 11 of Acala NemX Cotton.

    USDA-ARS?s Scientific Manuscript database

    Root-knot nematode (RKN, Meloidogyne incognita) resistance in Gossypium hirsutum ‘Acala NemX’ cotton is conferred by the recessive gene rkn1 (locus Mi2h-C11) on chromosome 11. The concentration of RKN, reniform nematode and other disease resistance determinants on chromosome 11 indicates that much c...

  3. Induction of systemic acquired resistance by Rotylenchulus reniformis and Meloidogyne incognita in cotton following separate and concomitant inoculations.

    USDA-ARS?s Scientific Manuscript database

    Systemic acquired resistance (SAR) can be elicited by virulent and avirulent pathogenic strains and SAR against plant-parasitic nematodes has been documented. Our objective was to determine whether co-infection of cotton by Meloidogyne incognita and Rotylenchulus reniformis affects the population le...

  4. Physiological effects of Meloidogyne incognita infection on cotton genotypes with differing levels of resistance in the greenhouse

    USDA-ARS?s Scientific Manuscript database

    Greenhouse tests were conducted to evaluate 1) the effect of Meloidogyne incognita infection in cotton on plant growth and physiology including the height-to-node ratio, chlorophyll content, dark adapted quantum yield of photosystem II, and leaf area, and 2) the extent to which moderate or high leve...

  5. Response of cucurbit rootstocks for grafted melon (Cucumis melo) to southern root-knot nematode, Meloidogyne incognita

    USDA-ARS?s Scientific Manuscript database

    Root-knot nematodes (RKN) are an important re-emerging pest of melon (Cucumis melo), due largely to the loss of methyl bromide as a pre-plant soil fumigant. Melon is highly susceptible to southern RKN, Meloidogyne incognita, which causes severe root galling and reduced melon fruit yields. Cucurbit...

  6. Induced systemic resistance of selected endophytic bacteria against Meloidogyne incognita on tomato.

    PubMed

    Munif, A; Hallmann, J; Sikora, R A

    2001-01-01

    In previous work, the four endophytic bacteria Pantoea agglomerans MK-29, Cedeca davisae MK-30, Enterobacter spp. MK-42 and Pseudomonas putida MT-19 were shown to reduce Meloidogyne incognita on tomato when applied as a seed treatment and/or soil drench. The objective of this work was to study these bacteria for their potential to induce systemic resistance against root knot nematodes on tomato. To guarantee spatial separation between inducing agent and pathogen a split-root system was chosen and inoculated with the bacteria as a drench application on one side of the root system and 6 days later with 2000 juveniles of Meloidogyne incognita on the other side of the split-root system. The experiment was maintained in the greenhouse and repeated once. The penetration rate of juveniles as well as the total number of root-knot galls and egg masses was recorded. Treatment with all four bacteria significantly reduced juvenile penetration and the number of root-knot galls when compared with the non-treated control. Induced systemic resistance is considered a possible control mechanism of endophytic bacteria against root-knot nematodes.

  7. Analysis and functional classification of transcripts from the nematode Meloidogyne incognita

    PubMed Central

    McCarter, James P; Dautova Mitreva, Makedonka; Martin, John; Dante, Mike; Wylie, Todd; Rao, Uma; Pape, Deana; Bowers, Yvette; Theising, Brenda; Murphy, Claire V; Kloek, Andrew P; Chiapelli, Brandi J; Clifton, Sandra W; Bird, David Mck; Waterston, Robert H

    2003-01-01

    Background Plant parasitic nematodes are major pathogens of most crops. Molecular characterization of these species as well as the development of new techniques for control can benefit from genomic approaches. As an entrée to characterizing plant parasitic nematode genomes, we analyzed 5,700 expressed sequence tags (ESTs) from second-stage larvae (L2) of the root-knot nematode Meloidogyne incognita. Results From these, 1,625 EST clusters were formed and classified by function using the Gene Ontology (GO) hierarchy and the Kyoto KEGG database. L2 larvae, which represent the infective stage of the life cycle before plant invasion, express a diverse array of ligand-binding proteins and abundant cytoskeletal proteins. L2 are structurally similar to Caenorhabditis elegans dauer larva and the presence of transcripts encoding glyoxylate pathway enzymes in the M. incognita clusters suggests that root-knot nematode larvae metabolize lipid stores while in search of a host. Homology to other species was observed in 79% of translated cluster sequences, with the C. elegans genome providing more information than any other source. In addition to identifying putative nematode-specific and Tylenchida-specific genes, sequencing revealed previously uncharacterized horizontal gene transfer candidates in Meloidogyne with high identity to rhizobacterial genes including homologs of nodL acetyltransferase and novel cellulases. Conclusions With sequencing from plant parasitic nematodes accelerating, the approaches to transcript characterization described here can be applied to more extensive datasets and also provide a foundation for more complex genome analyses. PMID:12702207

  8. Influence of Meloidogyne incognita on the Water Relations of Cotton Grown in Microplots

    PubMed Central

    Kirkpatrick, T. L.; Van Iersel, M. W.; Oosterhuis, D. M.

    1995-01-01

    The effects of Meloidogyne incognita on the growth and water relations of cotton were evaluated in a 2-year field study. Microplots containing methyl bromide-fumigated fine sandy loam soil were infested with the nematode and planted to cotton (Gossypium hirsutum L.). Treatments included addition of nematodes alone, addition of nematodes plus the insecticide-nematicide aldicarb (1.7 kg/ha), and an untreated control. Meloidogyne incognita population densities reached high levels in both treatments where nematodes were included. Root galling, plant height at harvest, and seed cotton yield were decreased by nematode infection. In older plants (89 days after planting [DAP]), leaf transpiration rates and stomatal conductance were reduced, and leaf temperature was increased by nematode infection. Nematode infection did not affect (P = 0.05) leaf water potential in either young or older plants but lowered the osmotic potential. The maximum rate and cumulative amount of water flowing through intact plants during a 24-hour period were lower, on both a whole-plant and per-unit-leaf-area basis, in infected plants than in control plants. Application of aldicarb moderated some of the nematode effects but did not eliminate them. PMID:19277313

  9. Influence of Meloidogyne incognita on the Water Relations of Cotton Grown in Microplots.

    PubMed

    Kirkpatrick, T L; Van Iersel, M W; Oosterhuis, D M

    1995-12-01

    The effects of Meloidogyne incognita on the growth and water relations of cotton were evaluated in a 2-year field study. Microplots containing methyl bromide-fumigated fine sandy loam soil were infested with the nematode and planted to cotton (Gossypium hirsutum L.). Treatments included addition of nematodes alone, addition of nematodes plus the insecticide-nematicide aldicarb (1.7 kg/ha), and an untreated control. Meloidogyne incognita population densities reached high levels in both treatments where nematodes were included. Root galling, plant height at harvest, and seed cotton yield were decreased by nematode infection. In older plants (89 days after planting [DAP]), leaf transpiration rates and stomatal conductance were reduced, and leaf temperature was increased by nematode infection. Nematode infection did not affect (P = 0.05) leaf water potential in either young or older plants but lowered the osmotic potential. The maximum rate and cumulative amount of water flowing through intact plants during a 24-hour period were lower, on both a whole-plant and per-unit-leaf-area basis, in infected plants than in control plants. Application of aldicarb moderated some of the nematode effects but did not eliminate them.

  10. Screening and identification of cucumber germplasm and rootstock resistance against the root-knot nematode (Meloidogyne incognita).

    PubMed

    Li, X Z; Chen, S X

    2017-04-13

    Root-knot nematodes (Meloidogyne spp) are destructive agricultural pests that reduce the productivity of cultivated vegetables worldwide, especially when vegetables are cropped continuously in greenhouses. Cucumbers (Cucumis sativus L.), in particular, suffer extensive damage due to root-knot nematodes, and only a few wild species are known to be resistant. Grafting of cultivated plants to rootstocks of known resistant germplasms could be an effective method to resolve this problem. In this study, 21 cucumber germplasms and seven rootstocks were evaluated for resistance based on the growth of cucumber seedlings and resistance indexes to Meloidogyne incognita, which were surveyed 25 days after inoculation with M. incognita. Cluster analysis and principal component analysis (PCA) were used to investigate the resistance of 21 cucumber germplasms and seven rootstocks based on their growth and resistance indexes after inoculation with M. incognita. These analyses showed that the 21 germplasms and seven rootstocks could be divided into three groups based upon their resistance levels: moderately resistant, susceptible, and highly susceptible to M. incognita. All 21 cucumber germplasms exhibited susceptibility or high susceptibility to M. incognita and most rootstocks exhibited moderate resistance. The PCA results were consistent with those of the clustering analysis. The Jinyou No.1 cultivar had the highest resistance to M. incognita among the 21 cucumber germplasms, and Huangzhen No.1 cultivar had the highest resistance among the seven rootstock cultivars.

  11. Gene expression analysis in Musa acuminata during compatible interactions with Meloidogyne incognita.

    PubMed

    Castañeda, Nancy Eunice Niño; Alves, Gabriel Sergio Costa; Almeida, Rosane Mansan; Amorim, Edson Perito; Fortes Ferreira, Claudia; Togawa, Roberto Coiti; Costa, Marcos Mota Do Carmo; Grynberg, Priscila; Santos, Jansen Rodrigo Pereira; Cares, Juvenil Enrique; Miller, Robert Neil Gerard

    2017-03-01

    Endoparasitic root-knot nematodes (RKNs) ( Meloidogyne spp.) cause considerable losses in banana ( Musa spp.), with Meloidogyne incognita a predominant species in Cavendish sub-group bananas. This study investigates the root transcriptome in Musa acuminata genotypes 4297-06 (AA) and Cavendish Grande Naine (CAV; AAA) during early compatible interactions with M. incognita . Roots were analysed by brightfield light microscopy over a 35 d period to examine nematode penetration and morphological cell transformation. RNA samples were extracted 3, 7 and 10 days after inoculation (DAI) with nematode J2 juveniles, and cDNA libraries were sequenced using lllumina HiSeq technology. Sequences were mapped to the M. acuminata ssp. malaccensis var. Pahang genome sequence, differentially expressed genes (DEGs) identified and transcript representation determined by gene set enrichment and pathway mapping. Microscopic analysis revealed a life cycle of M. incognita completing in 24 d in CAV and 27 d in 4279-06. Comparable numbers of DEGs were up- and downregulated in each genotype, with potential involvement of many in early host defence responses involving reactive oxygen species and jasmonate/ethylene signalling. DEGs revealed concomitant auxin metabolism and cell wall modification processes likely to be involved in giant cell formation. Notable transcripts related to host defence included those coding for leucine-rich repeat receptor-like serine/threonine-protein kinases, peroxidases, thaumatin-like pathogenesis-related proteins, and DREB, ERF, MYB, NAC and WRKY transcription factors. Transcripts related to giant cell development included indole acetic acid-amido synthetase GH3.8 genes, involved in auxin metabolism, as well as genes encoding expansins and hydrolases, involved in cell wall modification. Expression analysis in M. acuminata during compatible interactions with RKNs provides insights into genes modulated during infection and giant cell formation. Increased

  12. Nematicidal activity of 2-thiophenecarboxaldehyde and methylisothiocyanate from caper (Capparis spinosa) against Meloidogyne incognita.

    PubMed

    Caboni, Pierluigi; Sarais, Giorgia; Aissani, Nadhem; Tocco, Graziella; Sasanelli, Nicola; Liori, Barbara; Carta, Annarosa; Angioni, Alberto

    2012-08-01

    New pesticides based on plant extracts have recently gained interest in the development of nontoxic crop protection chemicals. Numerous research studies are focused on the isolation and identification of new active compounds derived from plants. In this manuscript we report about the use of the Mediterranean species Capparis spinosa as a potent natural nematicidal agent against the root knot nematodes Meloidogyne incognita. Leaves, stems, and caper buds of Capparis spinosa were used to obtain their methanol extracts (LME, SME, BME) that were successively in vitro tested against second stage nematode juveniles (J2). In terms of paralysis induction, the methanol extract of the stem part (SME) was found more effective against M. incognita and then the caper methanol buds and leaves extracts. The chemical composition analysis of the extracts carried out by GC/MS and LC/MS techniques showed that methylisothiocyanate was the main compound of SME. The EC50 for SME after 3 days of immersion was 215 ± 36 mg/L. The constituent components of SME such as 2-thiophenecarboxaldehyde and methylisothiocyanate were successively in vitro tested for their nematicidal activity against J2. Both compounds induced paralysis on root knot nematodes ranking first (EC50 = 7.9 ± 1.6, and 14.1 ± 1.9 mg/L respectively) for M. incognita. Moreover, 2-thiophenecarboxaldehyde showed a strong fumigant activity.

  13. Weed Hosts of Meloidogyne arenaria and M. incognita Common in Tobacco Fields in South Carolina.

    PubMed

    Tedford, E C; Fortnum, B A

    1988-10-01

    Thirty-two weed species common in South Carolina and one cultivar of tobacco were evaluated as hosts of Meloidogyne arenaria race 2 and M. incognita race 3 in the greenhouse. Egg mass production and galling differed (P < 0.05) among weed species. Chenopodium album, Euphorbia maculata, and Vicia villosa were good hosts of M. arenaria. Amaranthus palmeri, Rumex crispus, Amaranthus hybridus, Ambrosia artemisiifolia, lpomoea hederacea var. integriuscula, Setaria lutescens, Sida spinosa, Portulaca oleracea, and Rumex acetosella were moderate hosts. Taraxacum officinale, Ipomoea hederacea, Cyperus esculentus, Cynodon dactyIon, Echinochloa crus-galli, Eleusine indica, Sorghum halepense, Setaria viridis, Digitaria sanguinalis, and Datura stramonium were poor hosts for M. arenaria. Amaranthus palmeri, Amaranthus hybridus, Chenopodium album, Euphorbia maculata, Setaria lutescens, Vicia villosa, Sida spinosa, Rumex crispus, and Portulaca oleracea were moderate hosts and Ipomoea hederacea var. integriuscula, Xanthium strumarium, Cyperus esculentus, Cynodon dactylon, Paspalum notatum, Eleusine indica, Setaria viridis, and Rumex acetosella were poor hosts for M. incognita. None of the above were good hosts for M. incognita. Tobacco 'PD4' supported large numbers of both nematode species.

  14. Weed Hosts of Meloidogyne arenaria and M. incognita Common in Tobacco Fields in South Carolina

    PubMed Central

    Tedford, E. C.; Fortnum, B. A.

    1988-01-01

    Thirty-two weed species common in South Carolina and one cultivar of tobacco were evaluated as hosts of Meloidogyne arenaria race 2 and M. incognita race 3 in the greenhouse. Egg mass production and galling differed (P < 0.05) among weed species. Chenopodium album, Euphorbia maculata, and Vicia villosa were good hosts of M. arenaria. Amaranthus palmeri, Rumex crispus, Amaranthus hybridus, Ambrosia artemisiifolia, lpomoea hederacea var. integriuscula, Setaria lutescens, Sida spinosa, Portulaca oleracea, and Rumex acetosella were moderate hosts. Taraxacum officinale, Ipomoea hederacea, Cyperus esculentus, Cynodon dactyIon, Echinochloa crus-galli, Eleusine indica, Sorghum halepense, Setaria viridis, Digitaria sanguinalis, and Datura stramonium were poor hosts for M. arenaria. Amaranthus palmeri, Amaranthus hybridus, Chenopodium album, Euphorbia maculata, Setaria lutescens, Vicia villosa, Sida spinosa, Rumex crispus, and Portulaca oleracea were moderate hosts and Ipomoea hederacea var. integriuscula, Xanthium strumarium, Cyperus esculentus, Cynodon dactylon, Paspalum notatum, Eleusine indica, Setaria viridis, and Rumex acetosella were poor hosts for M. incognita. None of the above were good hosts for M. incognita. Tobacco 'PD4' supported large numbers of both nematode species. PMID:19290313

  15. Influence of infection of cotton by Rotylenchulus Reniformis and Meloidogyne Incognita on the production of enzymes involved in systemic acquired resistance.

    USDA-ARS?s Scientific Manuscript database

    Systemic acquired resistance (SAR), which results in enhanced defense mechanisms in plants, can be elicited by virulent and avirulent strains of pathogens including nematodes. Recent studies of nematode reproduction strongly suggest that Meloidogyne incognita and Rotylenchulus reniformis induce SAR ...

  16. Inheritance and identification of a major quantitative trait locus (QTL) that confers resistance to Meloidogyne incognita and a novel QTL for plant height in sweet sorghum

    USDA-ARS?s Scientific Manuscript database

    Southern root-knot nematodes (Meloidogyne incognita) are a pest on many economically important row crop and vegetable species and management relies on chemicals, plant resistance, and cultural practices such as crop rotation. Little is known about the inheritance of resistance to M. incognita or the...

  17. Effects of Interactions among Heterodera glycines, Meloidogyne incognita, and Host Genotype on Soybean Yield and Nematode Population Densities

    PubMed Central

    Niblack, T. L.; Hussey, R. S.; Boerma, H. R.

    1986-01-01

    The effects of host genotype and initial nematode population densities (Pi) on yield of soybean and soil population densities of Heterodera glycines (Hg) race 3 and Meloidogyne incognita (Mi) race 3 were studied in a greenhouse and field microplots in 1983 and 1984. Centennial (resistant to Hg and Mi), Braxton (resistant to Mi, susceptible to Hg), and Coker 237 (susceptible to Hg and Mi) were planted in soil infested with 0, 31, or 124 eggs of Hg and Mi, individually and in all combinations, per 100 cm³ soil. Yield responses of the soybean cultivars to individual and combined infestations of Hg and Mi were primarily dependent on soybean resistance or susceptibility to each species separately. Yield of Centennial was stimulated or unaffected by nematode treatments, yield of Braxton was suppressed by Hg only, and yield suppressions caused by Hg and Mi were additive and dependent on Pi for Coker 237. Other plant responses to nematodes were also dependent on host resistance or susceptibility. Population densities of Mi second-stage juveniles (J2) in soil were related to Mi Pi and remained constant in the presence of Hg for all three cultivars. Population densities of Hg J2 on the two Hg-susceptible Cultivars, Braxton and Coker 237, were suppressed in the presence of Mi at low Hg Pi. PMID:19294208

  18. Arthrobotrys oligospora-mediated biological control of diseases of tomato (Lycopersicon esculentum Mill.) caused by Meloidogyne incognita and Rhizoctonia solani.

    PubMed

    Singh, U B; Sahu, A; Sahu, N; Singh, R K; Renu, S; Singh, D P; Manna, M C; Sarma, B K; Singh, H B; Singh, K P

    2013-01-01

    To study the biocontrol potential of nematode-trapping fungus Arthrobotrys oligospora in protecting tomato (Lycopersicon esculentum Mill.) against Meloidogyne incognita and Rhizoctonia solani under greenhouse and field conditions. Five isolates of the nematode-trapping fungus Arthrobotrys oligospora isolated from different parts of India were tested against Meloidogyne incognita and Rhizoctonia solani in tomato (Lycopersicon esculentum Mill.) plants grown under greenhouse and field conditions. Arthrobotrys oligospora-treated plants showed enhanced growth in terms of shoot and root length and biomass, chlorophyll and total phenolic content and high phenylalanine ammonia lyase activity in comparison with M. incognita- and R. solani-inoculated plants. Biochemical profiling when correlated with disease severity and intensity in A. oligospora-treated and untreated plants indicate that A. oligospora VNS-1 offered significant disease reduction in terms of number of root galls, seedling mortality, lesion length, disease index, better plant growth and fruit yield as compared to M. incognita- and R. solani-challenged plants. The result established that A. oligospora VNS-1 has the potential to provide bioprotection agents against M. incognita and R. solani. Arthrobotrys oligospora can be a better environment friendly option and can be incorporated in the integrated disease management module of crop protection. Application of A. oligospora not only helps in the control of nematodes but also increases plant growth and enhances nutritional value of tomato fruits. Thus, it proves to be an excellent biocontrol as well as plant growth promoting agent. © 2012 The Society for Applied Microbiology.

  19. Sensitivity of Bedding Plants to Southern Root-knot Nematode, Meloidogyne incognita Race 3.

    PubMed

    Walker, J T; Melin, J B; Davis, J

    1994-12-01

    Thirty-two cultivars of 10 commonly-grown bedding plants, representing eight families, were evaluated for their response to infection by the root-knot nematode, Meloidogyne incognita race 3, under greenhouse conditions. Four ageratum cultivars, two marigold, and two salvia cultivars were rated resistant after exposure for 8 weeks. Four begonia, four celosia, one dianthus, one verbena, one vinca, and three pansy cultivars were susceptible. Three salvia, one begonia, one gerber, one verbena, and three vinca cultivars were slightly susceptible with an average of

  20. Sensitivity of Bedding Plants to Southern Root-knot Nematode, Meloidogyne incognita Race 3

    PubMed Central

    Walker, J. T.; Melin, J. B.; Davis, J.

    1994-01-01

    Thirty-two cultivars of 10 commonly-grown bedding plants, representing eight families, were evaluated for their response to infection by the root-knot nematode, Meloidogyne incognita race 3, under greenhouse conditions. Four ageratum cultivars, two marigold, and two salvia cultivars were rated resistant after exposure for 8 weeks. Four begonia, four celosia, one dianthus, one verbena, one vinca, and three pansy cultivars were susceptible. Three salvia, one begonia, one gerber, one verbena, and three vinca cultivars were slightly susceptible with an average of ≤ 1 gall per plant. Nematodes, at two initial population densities, affected the dry weights of only a few cultivars. The diversity of annual bedding plant germplasm available may provide adequate sources of resistance to this race of root-knot nematode. PMID:19279964

  1. Infection of Cultured Thin Cell Layer Roots of Lycopersicon esculentum by Meloidogyne incognita

    PubMed Central

    Radin, D. N.; Eisenback, J. D.

    1991-01-01

    A new aseptic culture system for studying interactions between tomato (Lycopersicon esculentum) and Meloidogyne incognita is described. Epidermal thin cell layer explants from peduncles of tomato produced up to 20 adventitious roots per culture in 4-9 days on Murashige &Scoog medium plus kinetin and indole acetic acid. Rooted cultures were transferred to Gamborg's B-5 medium and inoculated with infective second-stage juveniles. Gall formation was apparent 5 days after inoculation and egg production by mature females occurred within 25 days at 25 C in the susceptible genotypes Rutgers and Red Alert. Resistant genotypes LA655, LA656, and LA1022 exhibited a characteristic hypersensitive response. This system provides large numbers of cultured root tips for studies on the molecular basis of the host-parasite relationship. PMID:19283152

  2. Characterization of Anionic Peroxidases in Tomato Isolines Infected by Meloidogyne incognita

    PubMed Central

    Zacheo, G.; Orlando, C.; Bleve-Zacheo, T.

    1993-01-01

    Changes in peroxidase activity during nematode infection were studied using root extracts of tomato near-isogenic lines differing in resistance to Meloidogyne incognita. Total peroxidase activity increased slightly in crude extracts of four susceptible isolines but doubled in two resistant lines, Monita and Motaci. Nematode infection enhanced levels of both p-phenylenediamine-pyrocatechol oxidase and syringaldazine oxidase 7 days after inoculation, especially in resistant lines. This elevated peroxidase activity in resistant isolines was caused by an increase in anionic peroxidase activity. These enzymes, which likely are involved in lignification, were isolated and purified from tomato isolines by ammonium sulfate precipitation, high performance ion-exchange chromatography, and gel electrophoresis. The purified anionic peroxidase extracts contained an electrophoretic band with Rf 0.51 that was present in extracts of infected but not uninfected roots. PMID:19279765

  3. Infection of Cultured Thin Cell Layer Roots of Lycopersicon esculentum by Meloidogyne incognita.

    PubMed

    Radin, D N; Eisenback, J D

    1991-10-01

    A new aseptic culture system for studying interactions between tomato (Lycopersicon esculentum) and Meloidogyne incognita is described. Epidermal thin cell layer explants from peduncles of tomato produced up to 20 adventitious roots per culture in 4-9 days on Murashige &Scoog medium plus kinetin and indole acetic acid. Rooted cultures were transferred to Gamborg's B-5 medium and inoculated with infective second-stage juveniles. Gall formation was apparent 5 days after inoculation and egg production by mature females occurred within 25 days at 25 C in the susceptible genotypes Rutgers and Red Alert. Resistant genotypes LA655, LA656, and LA1022 exhibited a characteristic hypersensitive response. This system provides large numbers of cultured root tips for studies on the molecular basis of the host-parasite relationship.

  4. Reproduction of Virulent Isolates of Meloidogyne incognita on Susceptible and Mi-resistant Tomato

    PubMed Central

    Castagnone-Sereno, P.; Bongiovanni, M.; Dalmasso, A.

    1994-01-01

    The reproductive potential of natural and laboratory-selected Meloidogyne incognita isolates virulent against the tomato Mi resistance gene, all derived from a single egg-mass, were compared when the nematodes were inoculated on susceptible and resistant tomato. Fewer second-stage juveniles (P = 0.01) of the two virulent populations selected under laboratory conditions matured to females on the resistant tomato compared to the susceptible cultivar. In contrast, no differences were found between the number of egg masses produced on the resistant versus the susceptible tomato by the two natural virulent isolates. No clear general trends concerning the fecundity of the females could be inferred from the comparative analysis of the numbers of eggs per egg mass x tomato cultivar combination. These observations suggested that the genetic changes induced under environmentally controlled nematode growth might be different from those occurring in natural Mi-resistance breaking biotypes grown without environmental control. PMID:19279899

  5. Carbon Partitioning in Soybean Infected with Meloidogyne incognita and M. javanica

    PubMed Central

    Carneiro, R. G.; Mazzafera, P.; Ferraz, L. C. C. B.

    1999-01-01

    Seven-day-old seedlings of two cultivars (Cristalina and UFV ITM1) of Glycine max were inoculated with 0, 3,000, 9,000, or 27,000 eggs of Meloidogyne incognita race 3 or M. javanica and maintained in a greenhouse. Thirty days later, plants were exposed to ¹⁴CO₂ for 4 hours. Twenty hours after ¹⁴CO₂ exposure, the root fresh weight, leaf dry weight, nematode eggs per gram of root, total and specific radioactivity of carbohydrates in roots, and root carbohydrate content were evaluated. Meloidogyne javanica produced more eggs than M. incognita on both varieties. A general increase in root weight and a decrease in leaf weight with increased inoculum levels were observed. Gall tissue appeared to account for most of the root mass increase in seedlings infected with M. javanica. For both nematodes there was an increase of total radioactivity in the root system with increased levels of nematodes, and this was positively related to the number of eggs per gram fresh weight and to the root fresh weight, but negatively related to leaf dry weight. In most cases, specific radioactivities of sucrose and reducing sugars were also increased with increased inoculum levels. Highest specific radioactivities were observed with reducing sugars. Although significant changes were not observed in endogenous levels of carbohydrates, sucrose content was higher than reducing sugars. The data show that nematodes are strong metabolic sinks and significantly change the carbon distribution pattern in infected soybean plants. Carbon partitioning in plants infected with nematodes may vary with the nematode genotype. PMID:19270907

  6. Transcriptome analysis of resistant and susceptible alfalfa cultivars infected with root-knot nematode Meloidogyne incognita.

    PubMed

    Postnikova, Olga A; Hult, Maria; Shao, Jonathan; Skantar, Andrea; Nemchinov, Lev G

    2015-01-01

    Nematodes are one of the major limiting factors in alfalfa production. Root-knot nematodes (RKN, Meloidogyne spp.) are widely distributed and economically important sedentary endoparasites of agricultural crops and they may inflict significant damage to alfalfa fields. As of today, no studies have been published on global gene expression profiling in alfalfa infected with RKN or any other plant parasitic nematode. Very little information is available about molecular mechanisms that contribute to pathogenesis and defense responses in alfalfa against these pests and specifically against RKN. In this work, we performed root transcriptome analysis of resistant (cv. Moapa 69) and susceptible (cv. Lahontan) alfalfa cultivars infected with RKN Meloidogyne incognita, widespread root-knot nematode species and a major pest worldwide. A total of 1,701,622,580 pair-end reads were generated on an Illumina Hi-Seq 2000 platform from the roots of both cultivars and assembled into 45,595 and 47,590 transcripts in cvs Moapa 69 and Lahontan, respectively. Bioinformatic analysis revealed a number of common and unique genes that were differentially expressed in susceptible and resistant lines as a result of nematode infection. Although the susceptible cultivar showed a more pronounced defense response to the infection, feeding sites were successfully established in its roots. Characteristically, basal gene expression levels under normal conditions differed between the two cultivars as well, which may confer advantage to one of the genotypes toward resistance to nematodes. Differentially expressed genes were subsequently assigned to known Gene Ontology categories to predict their functional roles and associated biological processes. Real-time PCR validated expression changes in genes arbitrarily selected for experimental confirmation. Candidate genes that contribute to protection against M. incognita in alfalfa were proposed and alfalfa-nematode interactions with respect to resistance

  7. Management of Meloidogyne incognita with Chemicals and Cultivars in Cotton in a Semi-Arid Environment

    PubMed Central

    Wheeler, T. A.; Siders, K. T.; Anderson, M. G.; Russell, S. A.; Woodward, J. E.; Mullinix, B. G.

    2014-01-01

    Management of Meloidogyne incognita (root-knot nematode) in cotton in the United States was substantially affected by the decision to stop production of aldicarb by its principle manufacturer in 2011. The remaining commercially available tools to manage M. incognita included soil fumigation, nematicide seed treatments, postemergence nematicide application, and cultivars partially resistant to M. incognita. Small plot field studies were conducted on a total of nine sites from 2011–2013 to examine the effects of each of these tools alone or in combinations, on early season galling, late-season nematode density in soil, yield, and value ($/ha = lint value minus chemical costs/ha). The use of a partially resistant cultivar resulted in fewer galls/root system at 35 d after planting in eight of nine tests, lower root-knot nematode density late in the growing season for all test sites, higher lint yield in eight of nine sites, and higher value/ha in six of nine sites. Galls per root were reduced by aldicarb in three of nine sites and by 1,3-dichloropropene (1,3-D) in two of eight sites, relative to the nontreated control (no insecticide or nematicide treatment). Soil fumigation reduced M. incognita density late in the season in three of nine sites. Value/ha was not affected by chemical treatment in four of nine sites, but there was a cultivar × chemical interaction in four of nine sites. When value/ha was affected by chemical treatment, the nontreated control had a similar value to the treatment with the highest value/ha in seven of eight cultivar-site combinations. The next “best” value/ha were associated with seed treatment insecticide (STI) + oxamyl and aldicarb (similar value to the highest value/ha in six of eight cultivar-site combinations). The lowest valued treatment was STI + 1,3-D. In a semi-arid region, where rainfall was low during the spring for all three years, cultivars with partial resistance to M. incognita was the most profitable method of

  8. Induction of Systemic Acquired Resistance by Rotylenchulus reniformis and Meloidogyne incognita in Cotton Following Separate and Concomitant Inoculations.

    PubMed

    Aryal, Sudarshan K; Davis, Richard F; Stevenson, Katherine L; Timper, Patricia; Ji, Pingsheng

    2011-09-01

    Systemic acquired resistance (SAR) can be elicited by virulent and avirulent pathogenic strains and SAR against plant-parasitic nematodes has been documented. Our objective was to determine whether co-infection of cotton by Meloidogyne incognita and Rotylenchulus reniformis affects the population level of either nematode compared to infection by each species individually. Split-root trials were conducted in which plants were inoculated with i) R. reniformis only, ii) M. incognita only, iii) both R. reniformis and M. incognita, or iv) no nematodes. Half of the root system was inoculated with R. reniformis or M. incognita on day 0 and the other half with M. incognita or R. reniformis on day 0 or day 14 depending on the experiment. Experiments were conducted on cotton cultivar DP 0935 B2RF (susceptible to both nematodes), LONREN-1 (germplasm line resistant to R. reniformis), and M-120 RNR (germplasm line resistant to M. incognita), and tests were terminated 8 wk after the last inoculation. Both soil (vermiform) and roots (egg) extracted from each half of the root system to determine the total nematode population levels, and root galling was rated on a 0 to 10 scale. Mixed models analysis and comparison of least squares means indicated no differences in root galling (except on LONREN-1) or population levels when the two nematode species were introduced on the same day. When M. incognita was introduced 14 d after R. reniformis, reduction in galling (36% on DP 0935 and 33% on LONREN-1) and M. incognita population levels (35% on DP 0935 and 45% on LONREN-1) were significant (P ≤ 0.05). When R. reniformis was inoculated 14 d after M. incognita, reduction in R. reniformis population levels (18% on DP 0935 and 26% on M-120) were significant. This study documents for the first time that infection of cotton by a nematode can elicit SAR to another nematode species.

  9. Effects of Nematicides and Herbicides Alone or Combined on Meloidogyne incognita Egg Hatch and Development.

    PubMed

    Payan, L A; Johnson, A W; Littrell, R H

    1987-10-01

    The effects of nematicides carbofuran (C) and fenamiphos (F) and herbicides metribuzin (M) and trifluralin (T), alone and in combination, on hatching, penetration, development, and reproduction of Meloidogyne incognita race 3 were determined under laboratory conditions. To study hatching, entire egg masses were exposed to nematicides (6 mug/ml), herbicides (0.5 mug/ml), and their combinations over a period of 16 days; the hatched juveniles were extracted and counted every 48 hours. Second-stage juveniles that hatched from day 6 to day 8 were used as inoculum to determine the effects of the chemicals on penetration, development, and reproduction of M. incognita on tomato 4, 16, and 32 days after inoculation. F, F + T, and F + M inhibited hatching; whereas, C, T, M, C + T, and C + M did not affect hatching, penetration, development of females, or reproduction. Since so few juveniles hatched from the fenamiphos treatments, we were not able to use them for the postinfection development study. There was no apparent reduction in the effect of the nematicides by the herbicides.

  10. An In Vitro Test for Temperature Sensitivity and Resistance to Meloidogyne incognita in Tomato

    PubMed Central

    Haroon, Sanaa A.; Baki, A. Abdul; Huettel, R. N.

    1993-01-01

    An in vitro root explant tissue culture technique is described for determining susceptibility of tomato (Lycopersicon esculentum Mill.) breeding lines and cultivars to the root-knot nematode Meloidogyne incognita. Root explants were taken from 2-day-old seedlings cultured for 30 days at 28 C on Gamborg's B-5 medium with or without nematode inoculum. The remaining portion of the root and stem from the excised root explants was transferred to soil in pots and grown to maturity in the greenhouse. In vitro root explants were evaluated for growth and occurrence of juveniles, adults, and egg masses. The regenerated plants were used to produce more seed, The proposed technique is simple, reliable, and adapted to routine screening of large numbers of F₁ and F₂ samples, and it utilizes less space than tests performed on intact plants in the greenhouse or growth chamber. Evidence is presented also on the breakdown of resistance to M. incognita under high temperature stress using this in vitro root explant technique. PMID:19279747

  11. Relationships between the population density of Meloidogyne incognita and growth of tobacco.

    PubMed

    Hanounik, S B; Osborne, W W; Pirie, W R

    1975-10-01

    Seedlings of tobacco cultivars resistant (NC95) and susceptible (McNair 30) to Meloidogyne incognita were grown in 15-cm diameter clay pots containing steamed soil infested with 0, l, 2, 4, 8, 16, 32, and 64 eggs of M. incognita per 1.5 cm(3) soil. Plants were maintained in the greenhouse for 3 weeks, and then transferred to the field for 12 weeks. Growth of tobacco was expressed separately as dry weight of leaves and as plant height. Least squares regression analysis showed that tobacco growth-nematode density interactions are in agreement with Seinhorst's exponential model Y = m + (l-m) czp. Tobacco growth was not affected significantly as nematode density was increased from 0 to tolerance levels, which were approximately 2 and 1 eggs per 1.5 cm(3) soil for the resistant and susceptible cultivars, respectively. As nematode density was increased beyond tolerance level, tobacco growth decreased sharply until a minimum yield was approached. The minimum leaf weights and plant heights of the resistant cultivar at the highest nematode density were greater than those of the susceptible cultivar.

  12. Parasitic Variability of Meloidogyne incognita Populations on Susceptible and Resistant Cotton

    PubMed Central

    Kirkpatrick, T. L.; Sasser, J. N.

    1983-01-01

    Root gall induction and egg production by the four recognized host races and two cytological races of Meloidogyne incognita were compared on cotton Gossypium hirsutum cvs. Deltapine 16 (root-knot susceptible) and Auburn 634 (highly resistant). The 12 nematode populations included in the study were from various parts of the world. No population increases occurred on the highly resistant cultivar. After 45 days, populations of host races 1 and 2 induced slight root galling on both cuhivars with only limited reproduction. Host race 4 populations induced moderate root galling with higher reproduction on Deltapine 16 than that of race 1 or race 2 populations. Host race 3 populations induced severe root galling with population density increases of 7-30-fold. In a complementary study, 24 cotton cultivars or breeding lines were compared for suitability as hosts for a typical population of M. incognita race 3. The poorest hosts, 'Aubnru 623,' 'Auburn 634,' and 'McNair 220,' yielded fewer eggs after 45 days than were added initially. The best hosts - 'M-8.' 'DES 24-8,' 'McNair 235,' and 'Coker 20l' - yielded > 5 times as many eggs as were added initially. PMID:19295806

  13. Identification of msp1 Gene Variants in Populations of Meloidogyne incognita Using PCR-DGGE

    PubMed Central

    Adam, Mohamed; Hallmann, Johannes; Heuer, Holger

    2014-01-01

    Effectors of root-knot nematodes are essential for parasitism and prone to recognition by adapted variants of the host plants. This selective pressure initiates hypervariability of effector genes. Diversity of the gene variants within nematode populations might correlate with host preferences. In this study we developed a method to compare the distribution of variants of the effector gene msp1 among populations of Meloidogyne incognita. Primers were designed to amplify a 234-bp fragment of msp1. Sequencing of cloned PCR products revealed five msp1 variants from seven populations that were distinguishable in their reproduction on five host plants. A protocol for denaturing gradient gel electrophoresis (DGGE) was developed to separate these msp1 variants. DGGE for replicated pools of juveniles from the seven populations revealed ten variants of msp1. A correlation between the presence of a particular gene variant and the reproductive potential on particular hosts was not evident. Especially race 3 showed substantial variation within the population. DGGE fingerprints of msp1 tended to cluster the populations according to their reproduction rate on pepper. The developed method could be useful for analyzing population heterogeneity and epidemiology of M. incognita. PMID:25276001

  14. Use of Cucumis metuliferus as a Rootstock for Melon to Manage Meloidogyne incognita

    PubMed Central

    Sigüenza, Concepcion; Schochow, Martin; Turini, Tom; Ploeg, Antoon

    2005-01-01

    Root-knot nematode-susceptible melons (Cantaloupe) were grown in pots with varying levels of Meloidogyne incognita and were compared to susceptible melons that were grafted onto Cucumis metuliferus or Cucurbita moschata rootstocks. In addition, the effect of using melons as transplants in nematode-infested soil was compared to direct seeding of melons in nematode-infested soil. There were no differences in shoot or root weight, or severity of root galling between transplanted and direct-seeded non-grafted susceptible melon in nematode-infested soil. Susceptible melon grafted on C. moschata rootstocks had lower root gall ratings and, at high nematode densities, higher shoot weights than non-grafted susceptible melons. However, final nematode levels were not lower on the grafted than on the non-grafted plants, and it was therefore concluded that grafting susceptible melon on to C. moschata rootstock made the plants tolerant, but not resistant, to the nematodes. Grafting susceptible melons on C. metuliferus rootstocks also reduced levels of root galling, prevented shoot weight losses, and resulted in significantly lower nematode levels at harvest. Thus, C. metuliferus may be used as a rootstock for melon to prevent both growth reduction and a strong nematode buildup in M. incognita-infested soil. PMID:19262873

  15. Identification of Nematicidal Constituents of Notopterygium incisum Rhizomes against Bursaphelenchus xylophilus and Meloidogyne incognita.

    PubMed

    Liu, Gai; Lai, Daowan; Liu, Qi Zhi; Zhou, Ligang; Liu, Zhi Long

    2016-09-23

    During a screening program for new agrochemicals from Chinese medicinal herbs, the ethanol extract of Notopterygium incisum rhizomes was found to possess strong nematicidal activity against the two species of nematodes, Bursaphelenchus xylophilus and Meloidogyne incognita. Based on bioactivity-guided fractionation, the four constituents were isolated from the ethanol extract and identified as columbianetin, falcarindiol, falcarinol, and isoimperatorin. Among the four isolated constituents, two acetylenic compounds, falcarindiol and falcarinol (2.20-12.60 μg/mL and 1.06-4.96 μg/mL, respectively) exhibited stronger nematicidal activity than two furanocoumarins, columbianetin, and isoimperatorin (21.83-103.44 μg/mL and 17.21-30.91 μg/mL, respectively) against the two species of nematodes, B. xylophilus and M. incognita. The four isolated constituents also displayed phototoxic activity against the nematodes. The results indicate that the ethanol extract of N. incisum and its four isolated constituents have potential for development into natural nematicides for control of plant-parasitic nematodes.

  16. Interaction of Vesicular-arbuscular Mycorrhizal Fungi and Phosphorus with Meloidogyne incognita on Tomato

    PubMed Central

    Cason, K. M. Thomson; Hussey, R. S.; Roncadori, R. W.

    1983-01-01

    The influence of two vesicular-arbuscular mycorrhizal fungi and phosphorus (P) nutrition on penetration, development, and reproduction by Meloidogyne incognita on Walter tomato was studied in the greenhouse. Inoculation with either Gigaspora margarita or Glomus mosseae 2 wk prior to nematode inoculation did not alter infection by M. incognita compared with nonmycorrhizal plants, regardless of soil P level (either 3 μg [low P] or 30 μg [high P] available P/g soil). At a given soil P level, nematode penetration and reproduction did not differ in mycorrhizal and nonmycorrhizal plants. However, plants grown in high P soil had greater root weights, increased nematode penetration and egg production per plant, and decreased colonization by mycorrhizal fungi, compared with plants grown in low P soil. The number of eggs per female nematode on mycorrhizal and nonmycorrhizal plants was not influenced by P treatment. Tomato plants with split root systems grown in double-compartment containers which had either low P soil in both sides or high P in one side and low P in the other, were inoculated at transplanting with G. margarita and 2 wk later one-half of the split root system of each plant was inoculated with M. incognita larvae. Although the mycoorhizal fungus increased the inorganic P content of the root to a level comparable to that in plants grown in high P soil, nematode penetration and reproduction were not altered. In a third series of experiments, the rate of nematode development was not influenced by either the presence of G. margarita or high soil P, compared with control plants grown in low P soil. These data indicate that supplemental P (30 μ/g soil) alters root-knot nematode infection of tomato more than G. mosseae and G. margarita. PMID:19295826

  17. Potent nematicidal activity of phthalaldehyde, salicylaldehyde, and cinnamic aldehyde against Meloidogyne incognita.

    PubMed

    Caboni, Pierluigi; Aissani, Nadhem; Cabras, Tiziana; Falqui, Andrea; Marotta, Roberto; Liori, Barbara; Ntalli, Nikoletta; Sarais, Giorgia; Sasanelli, Nicola; Tocco, Graziella

    2013-02-27

    The nematicidal activity of selected aromatic aldehydes was tested against the root knot nematode Meloidogyne incognita. The most active aldehyde was phthalaldehyde (1) with an EC(50) value of 11 ± 6 mg/L followed by salicylaldehyde (2) and cinnamic aldehyde (3) with EC(50) values of 11 ± 1 and 12 ± 5 mg/L, respectively. On the other hand, structurally related aldehydes such as 2-methoxybenzaldehyde (21), 3,4-dimethoxybenzaldehyde, and vanillin (23) were not active at the concentration of 1000 mg/L. By liquid chromatography-mass spectrometry the reactivity of tested aldehydes against a synthetic peptide resembling the nematode cuticle was characterized. At the test concentration of 1 mM, the main adduct formation was observed for 3,4-dihydroxybenzaldehyde (22), 2-methoxybenzaldehyde (21), and 3,4-dimethoxybenzaldehyde. Considering that 2-methoxybenzaldehyde (21) and 3,4-dimethoxybenzaldehyde were not active against M. incognita in in vitro experiments led us to hypothesize a different mechanism of action rather than an effect on the external cuticle modification of nematodes. When the toxicity of the V-ATPase inhibitor pyocyanin (10) was tested against M. incognita J2 nematodes, an EC(50) at 24 h of 72 ± 25 mg/L was found. The redox-active compounds such as phthalaldehyde (1) and salicylaldehyde (2) may share a common mode of action inhibiting nematode V-ATPase enzyme. The results of this investigation reveal that aromatic redox-active aldehydes can be considered as potent nematicides, and further investigation is needed to completely clarify their mode of action.

  18. Competition between Heterodera glycines and Meloidogyne incognita or Pratylenchus penetrans: Independent Infection Rate Measurements

    PubMed Central

    Melakeberhan, Haddish; Dey, Jyotirmoy

    2003-01-01

    Competition on soybean between Heterodera glycines (race 3) and Meloidogyne incognita or H. glycines and Pratylenchus penetrans were investigated in greenhouse experiments. Each pair of nematode species was mixed in 3-ml suspensions at ratios of 1,000:0, 750:250, 500:500, 250:750, and 0:1,000 second-stage juveniles or mixed stages for P. penetrans. Nematodes from a whole root system were counted and infection rates standardized per 1,000 nematodes (per replication) prior to testing the null hypothesis through a lack-of-fit F-test. Although the effect of increasing H. glycines proportions on the infection rate of M. incognita was generally adverse, the rate deviated significantly from a trend of linear decline at the 75% H. glycines level in one of two experiments. All lack-of-fit F-tests for the H. glycines and P. penetrans mix were significant, indicating that infection rates for both nematodes varied considerably across inocula. The infection rate of H. glycines decreased with increasing P. penetrans proportions. The rate of P. penetrans infection increased with increasing H. glycines proportions up to the 50% level, but declined at the 75% level. Competition had no effect on nematode development. The general adverse relationships between M. incognita and H. glycines and those between P. penetrans and H. glycines showed a linear trend. The relationship between H. glycines and P. penetrans indicates that the former may be competitive when present at higher proportions than the latter. In this study we have evaluated nematode competition under controlled conditions and provide results that can form a basis for understanding the physical and physiological trends of multiple nematode interactions. Methods critical to data analyses also are outlined. PMID:19265967

  19. Acetic Acid, 2-Undecanone, and (E)-2-Decenal Ultrastructural Malformations on Meloidogyne incognita

    PubMed Central

    Ntalli, Nikoletta; Ratajczak, Marlena; Oplos, Chrisostomos; Menkissoglu-Spiroudi, Urania; Adamski, Zbigniew

    2016-01-01

    The use of natural compounds to control phytonematodes is significantly increasing, as most of the old synthetic pesticides have been banned due to their eco-hostile character. Plant secondary metabolites are now evaluated as biologically active molecules against Meloidogyne spp. but their target site in the nematode body is rarely specified. Herein, we report on the ultrastructure modifications of the Meloidogyne incognita J2 after treatment with nematicidal plant secondary metabolites, that is acetic acid, (E)-2-decenal, and 2-undecanone. The commercial nematicide fosthiazate acting on acetylcholinesterase was used as control. For this reason, scanning electron microscopy and transmission electron microscopy have been employed. The acetic acid mainly harmed the cuticle, degenerated the nuclei of pseudocoel cells, and vacuolised the cytoplasm. The (E)-2-decenal and 2-undecanone did neither harm to the cuticle nor the somatic muscles but they degenerated the pseudocoel cells. (E)-2-decenal caused malformation of somatic muscles. According to the above, the nematicidal compounds seem to enter the nematode body principally via the digestive system rather than the cuticle, since the main part of the damage is internal. PMID:28154431

  20. Resistance to Meloidogyne incognita Race 3 and Rotylenchulus reniformis in Wild Accessions of Gossypium hirsutum and G. barbadense from Mexico

    PubMed Central

    Robinson, A. F.; Percival, A. E.

    1997-01-01

    Forty-six accessions of G. hirsutum and two of G. barbadense were examined for resistance to Meloidogyne incognita race 3 and Rotylenchulus reniformis in environmental growth chamber experiments, with the objective of finding new sources of resistance. Only the G. barbadense accessions, TX-1347 and TX-1348, supported significantly less reproduction by R. reniformis than the susceptible control, Deltapine 16 (USDA accession SA-1186). However, they were highly susceptible to M. incognita race 3. The G. hirsutum accessions TX-1174, TX-1440, TX-2076, TX-2079, and TX-2107 had levels of resistance to M. incognita race 3 as great as or greater than those of Clevewilt 6 and Wild Mexican Jack Jones, which are the primary sources of resistance to M. incognita race 3 in the most resistant breeding lines. No accession was as resistant as the highly resistant line Auburn 623 RNR (SA-1492). Resistant accessions were from the Mexican coastal states of Campeche, Quintana Roo, Tabasco, Veracruz, and Yucatan. Populations of R. reniformis from Alabama, Mississippi, Louisiana, and Texas, and of M. incognita race 3 from Mississippi, Texas, and California, had similar reproductive rates on resistant genotypes. Thus, new sources of resistance to M. incognita race 3 but not to R. reniformis were identified in wild accessions of G. hirsutum from southern Mexico. PMID:19274280

  1. Nematicidal activity of fervenulin isolated from a nematicidal actinomycete, Streptomyces sp. CMU-MH021, on Meloidogyne incognita.

    PubMed

    Ruanpanun, Pornthip; Laatsch, Hartmut; Tangchitsomkid, Nuchanart; Lumyong, Saisamorn

    2011-06-01

    An isolate of the actinomycete, Streptomyces sp. CMU-MH021 produced secondary metabolites that inhibited egg hatch and increased juvenile mortality of the root-knot nematode Meloidogyne incognita in vitro. 16S rDNA gene sequencing showed that the isolate sequence was 99% identical to Streptomyces roseoverticillatus. The culture filtrates form different culture media were tested for nematocidal activity. The maximal activity against M. incognita was obtained by using modified basal (MB) medium. The nematicidal assay-directed fractionation of the culture broth delivered fervenulin (1) and isocoumarin (2). Fervenulin, a low molecular weight compound, shows a broad range of biological activities. However, nematicidal activity of fervenulin was not previously reported. The nematicidal activity of fervenulin (1) was assessed using the broth microdilution technique. The lowest minimum inhibitory concentrations (MICs) of the compound against egg hatch of M. incognita was 30 μg/ml and juvenile mortality of M. incognita increasing was observed at 120 μg/ml. Moreover, at the concentration of 250 μg/ml fervenulin (1) showed killing effect on second-stage nematode juveniles of M. incognita up to 100% after incubation for 96 h. Isocoumarin (2), another bioactive compound produced by Streptomyces sp. CMU-MH021, showed weak nematicidal activity with M. incognita.

  2. Nematicidal Activity of trans-2-Hexenal against Southern Root-Knot Nematode (Meloidogyne incognita) on Tomato Plants.

    PubMed

    Lu, Hongbao; Xu, Shuangyu; Zhang, Wenjuan; Xu, Chunmei; Li, Beixing; Zhang, Daxia; Mu, Wei; Liu, Feng

    2017-01-25

    Botanical nematicides have recently received increasing interest because of the high risks of some traditional nematicides to human health and the environment. This study evaluated the nematicidal activity of a plant volatile, trans-2-hexenal, against Meloidogyne incognita. This compound exhibited higher activity in a fumigation experiment than in the aqueous phase in vitro. Both in pot tests and in field trials, trans-2-hexenal showed significant efficacy against M. incognita while maintaining excellent plant growth, especially at doses of 1000 and 500 L ha(-1), which were superior to that of abamectin at 180 g ha(-1) via hole application treatment but not significantly different from fumigation with 400 kg ha(-1) of dazomet. Furthermore, plants treated with 500 L ha(-1) trans-2-hexenal had fruit yields 20.2 and 45% greater than the control group. On this basis, trans-2-hexenal may be a potential alternative fumigation agent for controlling M. incognita on tomato crops.

  3. Management of Root-knot Nematode (Meloidogyne incognita) on Pittosporum tobira Under Greenhouse, Field, and On-farm Conditions in Florida

    PubMed Central

    Baidoo, Richard; Mengistu, Tesfamariam; McSorley, Robert; Stamps, Robert H.; Brito, Janete; Crow, William T.

    2017-01-01

    Root-knot nematodes are important pests of cut foliage crops in Florida. Currently, effective nematicides for control of these nematodes on cut foliage crops are lacking. Hence, research was conducted at the University of Florida to identify pesticides or biopesticides that could be used to manage these nematodes. The research comprised on-farm, field, and greenhouse trials. Nematicide treatments evaluated include commercial formulations of spirotetramat, furfural, and Purpureocillium lilacinum (=Paecilomyces lilacinus) strain 251. Treatment applications were made during the spring and fall seasons according to manufacturer’s specifications. Efficacy was evaluated based on J2/100 cm3 of soil, J2/g of root, and crop yield (kg/plot). Unlike spirotetramat, which did not demonstrate any measurable effects on Meloidogyne incognita J2 in the soil, furfural and P. lilacinum were marginally effective in reducing the population density of M. incognita on Pittosporum tobira. However, nematode reduction did not affect yield significantly. Although furfural and P. lilacinum have some potential for management of M. incognita on cut foliage crops, their use as a lone management option would likely not provide the needed level of control. Early treatment application following infestation provided greater J2 suppression compared to late application, suggesting the need for growers to avoid infested fields. PMID:28706312

  4. Management of Root-knot Nematode (Meloidogyne incognita) on Pittosporum tobira Under Greenhouse, Field, and On-farm Conditions in Florida.

    PubMed

    Baidoo, Richard; Mengistu, Tesfamariam; McSorley, Robert; Stamps, Robert H; Brito, Janete; Crow, William T

    2017-06-01

    Root-knot nematodes are important pests of cut foliage crops in Florida. Currently, effective nematicides for control of these nematodes on cut foliage crops are lacking. Hence, research was conducted at the University of Florida to identify pesticides or biopesticides that could be used to manage these nematodes. The research comprised on-farm, field, and greenhouse trials. Nematicide treatments evaluated include commercial formulations of spirotetramat, furfural, and Purpureocillium lilacinum (=Paecilomyces lilacinus) strain 251. Treatment applications were made during the spring and fall seasons according to manufacturer's specifications. Efficacy was evaluated based on J2/100 cm(3) of soil, J2/g of root, and crop yield (kg/plot). Unlike spirotetramat, which did not demonstrate any measurable effects on Meloidogyne incognita J2 in the soil, furfural and P. lilacinum were marginally effective in reducing the population density of M. incognita on Pittosporum tobira. However, nematode reduction did not affect yield significantly. Although furfural and P. lilacinum have some potential for management of M. incognita on cut foliage crops, their use as a lone management option would likely not provide the needed level of control. Early treatment application following infestation provided greater J2 suppression compared to late application, suggesting the need for growers to avoid infested fields.

  5. Effect of a Terminated Cover Crop and Aldicarb on Cotton Yield and Meloidogyne incognita Population Density.

    PubMed

    Wheeler, T A; Leser, J F; Keeling, J W; Mullinix, B

    2008-06-01

    Terminated small grain cover crops are valuable in light textured soils to reduce wind and rain erosion and for protection of young cotton seedlings. A three-year study was conducted to determine the impact of terminated small grain winter cover crops, which are hosts for Meloidogyne incognita, on cotton yield, root galling and nematode midseason population density. The small plot test consisted of the cover treatment as the main plots (winter fallow, oats, rye and wheat) and rate of aldicarb applied in-furrow at-plant (0, 0.59 and 0.84 kg a.i./ha) as subplots in a split-plot design with eight replications, arranged in a randomized complete block design. Roots of 10 cotton plants per plot were examined at approximately 35 days after planting. Root galling was affected by aldicarb rate (9.1, 3.8 and 3.4 galls/root system for 0, 0.59 and 0.84 kg aldicarb/ha), but not by cover crop. Soil samples were collected in mid-July and assayed for nematodes. The winter fallow plots had a lower density of M. incognita second-stage juveniles (J2) (transformed to Log(10) (J2 + 1)/500 cm(3) soil) than any of the cover crops (0.88, 1.58, 1.67 and 1.75 Log(10)(J2 + 1)/500 cm(3) soil for winter fallow, oats, rye and wheat, respectively). There were also fewer M. incognita eggs at midseason in the winter fallow (3,512, 7,953, 8,262 and 11,392 eggs/500 cm(3) soil for winter fallow, oats, rye and wheat, respectively). Yield (kg lint per ha) was increased by application of aldicarb (1,544, 1,710 and 1,697 for 0, 0.59 and 0.84 kg aldicarb/ha), but not by any cover crop treatments. These results were consistent over three years. The soil temperature at 15 cm depth, from when soils reached 18 degrees C to termination of the grass cover crop, averaged 9,588, 7,274 and 1,639 centigrade hours (with a minimum threshold of 10 degrees C), in 2005, 2006 and 2007, respectively. Under these conditions, potential reproduction of M. incognita on the cover crop did not result in a yield penalty.

  6. Assessment of DAPG-producing Pseudomonas fluorescens for Management of Meloidogyne incognita and Fusarium oxysporum on Watermelon

    PubMed Central

    Meyer, Susan L. F.; Everts, Kathryne L.; Gardener, Brian McSpadden; Masler, Edward P.; Abdelnabby, Hazem M. E.; Skantar, Andrea M.

    2016-01-01

    Pseudomonas fluorescens isolates Clinto 1R, Wayne 1R, and Wood 1R, which produce the antibiotic 2,4-diacetylphloroglucinol (DAPG), can suppress soilborne diseases and promote plant growth. Consequently, these beneficial bacterial isolates were tested on watermelon plants for suppression of Meloidogyne incognita (root-knot nematode: RKN) and Fusarium oxysporum f. sp. niveum (Fon). In a greenhouse trial, Wayne 1R root dip suppressed numbers of RKN eggs per gram root on ‘Charleston Gray’ watermelon by 28.9%. However, in studies focused on ‘Sugar Baby’ watermelon, which is commercially grown in Maryland, a Wayne 1R root dip did not inhibit RKN reproduction or plant death caused by Fon. When all three isolates were applied as seed coats, plant stand in the greenhouse was reduced up to 60% in treatments that included Fon ± P. fluorescens, and eggs per gram root did not differ among treatments. In a microplot trial with Clinto 1R and Wayne 1R root dips, inoculation with P. fluorescens and/or Fon resulted in shorter vine lengths than treatment with either P. fluorescens isolate plus RKN. Root weights, galling indices, eggs per gram root, and second-stage juvenile (J2) numbers in soil were similar among all RKN-inoculated treatments, and fruit production was not affected by treatment. Plant death was high in all treatments. These studies demonstrated that the tested P. fluorescens isolates resulted in some inhibition of vine growth in the field, and were not effective for enhancing plant vigor or suppressing RKN or Fon on watermelon. PMID:27168652

  7. Mitochondrial genomes of Meloidogyne chitwoodi and M. incognita (Nematoda: Tylenchina): comparative analysis, gene order and phylogenetic relationships with other nematodes.

    PubMed

    Humphreys-Pereira, Danny A; Elling, Axel A

    2014-01-01

    Root-knot nematodes (Meloidogyne spp.) are among the most important plant pathogens. In this study, the mitochondrial (mt) genomes of the root-knot nematodes, M. chitwoodi and M. incognita were sequenced. PCR analyses suggest that both mt genomes are circular, with an estimated size of 19.7 and 18.6-19.1kb, respectively. The mt genomes each contain a large non-coding region with tandem repeats and the control region. The mt gene arrangement of M. chitwoodi and M. incognita is unlike that of other nematodes. Sequence alignments of the two Meloidogyne mt genomes showed three translocations; two in transfer RNAs and one in cox2. Compared with other nematode mt genomes, the gene arrangement of M. chitwoodi and M. incognita was most similar to Pratylenchus vulnus. Phylogenetic analyses (Maximum Likelihood and Bayesian inference) were conducted using 78 complete mt genomes of diverse nematode species. Analyses based on nucleotides and amino acids of the 12 protein-coding mt genes showed strong support for the monophyly of class Chromadorea, but only amino acid-based analyses supported the monophyly of class Enoplea. The suborder Spirurina was not monophyletic in any of the phylogenetic analyses, contradicting the Clade III model, which groups Ascaridomorpha, Spiruromorpha and Oxyuridomorpha based on the small subunit ribosomal RNA gene. Importantly, comparisons of mt gene arrangement and tree-based methods placed Meloidogyne as sister taxa of Pratylenchus, a migratory plant endoparasitic nematode, and not with the sedentary endoparasitic Heterodera. Thus, comparative analyses of mt genomes suggest that sedentary endoparasitism in Meloidogyne and Heterodera is based on convergent evolution. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. The nematicidal effect of some bacterial biofertilizers on Meloidogyne incognita in sandy soil

    PubMed Central

    El-Hadad, M.E.; Mustafa, M.I.; Selim, Sh.M.; El-Tayeb, T.S.; Mahgoob, A.E.A.; Abdel Aziz, Norhan H.

    2011-01-01

    In a greenhouse experiment, the nematicidal effect of some bacterial biofertilizers including the nitrogen fixing bacteria (NFB) Paenibacillus polymyxa (four strains), the phosphate solubilizing bacteria (PSB) Bacillus megaterium (three strains) and the potassium solubilizing bacteria (KSB) B. circulans (three strains) were evaluated individually on tomato plants infested with the root-knot nematode Meloidogyne incognita in potted sandy soil. Comparing with the uninoculated nematode-infested control, the inoculation with P. polymyxa NFB7, B. megaterium PSB2 and B. circulans KSB2, increased the counts of total bacteria and total bacterial spores in plants potted soil from 1.2 to 2.6 folds estimated 60 days post-inoculation. Consequently, the inoculation with P. polymyxa NFB7 increased significantly the shoot length (cm), number of leaves / plant, shoot dry weight (g) / plant and root dry weight (g) / plant by 32.6 %, 30.8 %, 70.3 % and 14.2 %, respectively. Generally, the majority treatments significantly reduced the nematode multiplication which was more obvious after 60 days of inoculation. Among the applied strains, P. polymyxa NFB7, B. megaterium PSB2 and B. circulans KSB2 inoculations resulted in the highest reduction in nematode population comparing with the uninoculated nematode-infested control. They recorded the highest reduction in numbers of hatched juveniles/root by 95.8 %, females/root by 63.75 % and juveniles/1kg soil by 57.8 %. These results indicated that these bacterial biofertilizers are promising double purpose microorganisms for mobilizing of soil nutrients (nitrogen, phosphate and potassium) and for the biological control of M. incognita. PMID:24031611

  9. The nematicidal effect of some bacterial biofertilizers on Meloidogyne incognita in sandy soil.

    PubMed

    El-Hadad, M E; Mustafa, M I; Selim, Sh M; El-Tayeb, T S; Mahgoob, A E A; Abdel Aziz, Norhan H

    2011-01-01

    In a greenhouse experiment, the nematicidal effect of some bacterial biofertilizers including the nitrogen fixing bacteria (NFB) Paenibacillus polymyxa (four strains), the phosphate solubilizing bacteria (PSB) Bacillus megaterium (three strains) and the potassium solubilizing bacteria (KSB) B. circulans (three strains) were evaluated individually on tomato plants infested with the root-knot nematode Meloidogyne incognita in potted sandy soil. Comparing with the uninoculated nematode-infested control, the inoculation with P. polymyxa NFB7, B. megaterium PSB2 and B. circulans KSB2, increased the counts of total bacteria and total bacterial spores in plants potted soil from 1.2 to 2.6 folds estimated 60 days post-inoculation. Consequently, the inoculation with P. polymyxa NFB7 increased significantly the shoot length (cm), number of leaves / plant, shoot dry weight (g) / plant and root dry weight (g) / plant by 32.6 %, 30.8 %, 70.3 % and 14.2 %, respectively. Generally, the majority treatments significantly reduced the nematode multiplication which was more obvious after 60 days of inoculation. Among the applied strains, P. polymyxa NFB7, B. megaterium PSB2 and B. circulans KSB2 inoculations resulted in the highest reduction in nematode population comparing with the uninoculated nematode-infested control. They recorded the highest reduction in numbers of hatched juveniles/root by 95.8 %, females/root by 63.75 % and juveniles/1kg soil by 57.8 %. These results indicated that these bacterial biofertilizers are promising double purpose microorganisms for mobilizing of soil nutrients (nitrogen, phosphate and potassium) and for the biological control of M. incognita.

  10. Effect of Simultaneous Water Deficit Stress and Meloidogyne incognita Infection on Cotton Yield and Fiber Quality.

    PubMed

    Davis, R F; Earl, H J; Timper, P

    2014-06-01

    Both water deficit stress and Meloidogyne incognita infection can reduce cotton growth and yield, and drought can affect fiber quality, but the effect of nematodes on fiber quality is not well documented. To determine whether nematode parasitism affects fiber quality and whether the combined effects of nematode and drought stress on yield and quality are additive (independent effects), synergistic, or antagonistic, we conducted a study for 7 yr in a field infested with M. incognita. A split-plot design was used with the main plot factor as one of three irrigation treatments (low [nonirrigated], moderate irrigation, and high irrigation [water-replete]) and the subplot factor as 0 or 56 l/ha 1,3-dichloropropene. We prevented water deficit stress in plots designated as water-replete by supplementing rainfall with irrigation. Plots receiving moderate irrigation received half the water applied to the water-replete treatment. The severity of root galling was greater in nonfumigated plots and in plots receiving the least irrigation, but the amount of irrigation did not influence the effect of fumigation on root galling (no irrigation × fumigation interaction). The weights of lint and seed harvested were reduced in nonfumigated plots and also decreased as the level of irrigation decreased, but fumigation did not influence the effect of irrigation. Nematodes affected fiber quality by increasing micronaire readings but typically had little or no effect on percent lint, fiber length (measured by HVI), uniformity, strength, elongation, length (based on weight or number measured by AFIS), upper quartile length, or short fiber content (based on weight or number). Micronaire also was increased by water deficit stress, but the effects from nematodes and water stress were independent. We conclude that the detrimental effects caused to cotton yield and quality by nematode parasitism and water deficit stress are independent and therefore additive.

  11. Sterol Composition and Ecdysteroid Content of Eggs of the Root-knot Nematodes Meloidogyne incognita and M. arenaria

    PubMed Central

    Chitwood, David J.; McClure, Michael A.; Feldlaufer, Mark F.; Lusby, William R.; Oliver, Tames E.

    1987-01-01

    Free and esterified sterols of eggs of the root-knot nematodes Meloidogyne incognita races 2 and 3 and M. arenaria race 1 were isolated and identified by gas-liquid chromatography-mass spectrometry. The major sterols of eggs of each race were 24-ethylcholesterol (33.4-38.8% of total sterol), 24-ethylcholestanol (18.3-25.3%), 24-methylcholesterol (8.6-11.7%), 24-methylcholestanol (7.7-12.5%), and cholesterol (4.6-11.6%). Consequently, the major metabolic transformation performed by Meloidogyne females or eggs upon host sterols appeared to be saturation of the sterol nucleus. The free and esterified sterols of the same race did not differ appreciably, except for a slight enrichment of the steryl esters in cholesterol. Although the sterol composition of Meloidogyne eggs differed from that of other life stages of other genera of plant-parasitic nematodes, the three Meloidogyne races could not be distinguished from each other by their egg sterols. Ecdysteroids, compounds with hormonal function in insects, were not detected by radioimmunoassay in the Meloidogyne eggs either as free ecdysteroids or as polar conjugates. PMID:19290155

  12. [The participation of salicylic and jasmonic acids in genetic and induced resistance of tomato to Meloidogyne incognita (Kofoid and White, 1919)].

    PubMed

    Zinov'eva, S V; Vasiukova, N I; Udalova, Zh V; Gerasimova, N G

    2013-01-01

    Salicylic (SA) and jasmonic (JA) acids are the best known mediators of signal systems in plants. In this investigation the participation and character of interactions between SA- and JA-signals under the induced and genetic resistance of plants to nematodes was investigated on the model system tomato (Lycopersicon esculentum) and the root-knot nematode Meloidogyne incognita. This study demonstrates that application of JA and SA to tomato foliage induces systemic effects that suppress root-knot nematode infestation, inhibition of nematode reproduction, and also increased activity of LOX and PAL, the enzymes of biosynthesis of JA and SA. JA treatment did not inhibit Mz-mediated resistance, which suggests a lack of signaling conflicts between these two forms of defense.

  13. Penetration and Development of Meloidogyne incognita on Roots of Resistant Soybean Genotypes

    PubMed Central

    Herman, M.; Hussey, R. S.; Boerma, H. R.

    1991-01-01

    Meloidogyne incognita penetration and development were studied in roots of highly resistant (PI 96354, PI 417444), resistant (Forrest), and susceptible (Bossier) soybean genotypes. Although more second-stage juveniles (J2) had penetrated roots of PI 96354 and PI 417444 than roots of Forrest and Bossier by 2 days after inoculation, fewer J2 were present in roots of PI 96354 at 4 days after inoculation. Juvenile development in all genotypes was evident by 6 days after inoculation, with the highest number of swollen J2 present in roots of Bossier. At 16 days after inoculation, roots of PI 96354 had 87%, 74%, and 53% fewer J2 than were present in roots of Bossier, Forrest, and PI 417444, respectively. Differential emigration of J2, not fewer invasion sites, was responsible for the low number of nematodes in roots of the highly resistant PI 96354. Some 72% of the J2 penetrating the roots of this genotype emerged within 5 days after inoculation, whereas 4%, 54%, and 83% emerged from roots of Bossier, Forrest, and PI 417444, respectively. Penetration of roots of PI 96354 decreased the ability of J2 emerging from these roots to infect other soybean roots. PMID:19283106

  14. Relative Efficacy of Selected Volatile and Nonvolatile Nematicides for Control of Meloidogyne incognita on Tobacco.

    PubMed

    Brodie, B B; Good, J M

    1973-01-01

    Root-knot nematode control and tobacco yields in plots infested with Meloidogyne incognita and treated with the nonvolatile nematicides, aldicarb, Mocap (R), or Nemacur (R) were greater than those on similar plots treated with volatile nematicides such as DD, DD + MENCS, SD14647 or tetrachlorothiophene. Root-knot control and tobacco yields in plots treated with carbofuran or Dasanit (R) were eqtual to that obtained with DD + MENCS, but less than that obtained with the other volatile soil nematicides. The most efficient dosage was 3.4 kg/hectare active ingredient for aldicarb and Mocap (R) and 10.0 kg/hectare for Dasanit (R). Carbofuran and Nemacur (R) were equally as effective at 4.2 kg/hectare as they were at higher dosages. The most efficient dosage of DD and SD14647 was 84 liters/hectare. Aldicarb and Dasanit (R) resulted in better nematode control and tobacco yields when incorporated into the top 15-20 cm of soil than when incorporated into the top 5-10 cm of soil. Nemacur (R) and Mocap (R) performed better when incorporated into the top 5-10 cm of soil, and carbofuran performed better when applied in the seed furrow (placed 15-20 cm deep in a 5-cm band and bedded).

  15. Nematostatic Activity of Oxamyl and N,N-Dimethyl-1-cyanoformamide (DMCF) on Meloidogyne incognita Juveniles

    PubMed Central

    McGarvey, B. D.; Potter, J. W.; Chiba, M.

    1984-01-01

    The nematostatic activity of oxamyl, methyl-N',N'-dimethy]-N-hydroxy-l-thiooxamimidate (oxamyl-oxime) and N,N-dimethyl-l-cyanoformamide (DMCF) was studied by immersing 10 Meloidogyne incognita second-stage juveniles into aqueous solutions of various concentrations of each chemical. At concentrations of 500 to 8,000 μg/ml, oxamyl quickly immobilized immersed juveniles. In all other concentrations studied (down to 4 μg/ml), oxamyl stopped or reduced movement of juveniles within 24 hours. DMCF also quickly immobilized juveniles at concentrations of 4,000 and 8,000 μg/ml and reduced movement at 2,000 μg/ml. Lower concentrations had no observed effect on movement. In solutions of the oxime from 2,000 to 8,000 μg/ml, some reduction of movement was observed, but most juveniles maintained some motion over a period of 24 hours. Juveniles were transferred to water from 4,000 μg/ml solutions of oxamyl and DMCF after various intervals of time in order to determine the effect of duration of exposure to the chemicals on the ability of the immobilized juveniles to recover normal motion. Some recovery was observed even after 24 hours of exposure to DMCF, but none after exposure to oxamyl for longer than 40 minutes. PMID:19294031

  16. Nematicidal activity of mint aqueous extracts against the root-knot nematode Meloidogyne incognita.

    PubMed

    Caboni, Pierluigi; Saba, Marco; Tocco, Graziella; Casu, Laura; Murgia, Antonio; Maxia, Andrea; Menkissoglu-Spiroudi, Urania; Ntalli, Nikoletta

    2013-10-16

    The nematicidal activity and chemical characterization of aqueous extracts and essential oils of three mint species, namely, Mentha × piperita , Mentha spicata , and Mentha pulegium , were investigated. The phytochemical analysis of the essential oils was performed by means of GC-MS, whereas the aqueous extracts were analyzed by LC-MS. The most abundant terpenes were isomenthone, menthone, menthol, pulegone, and carvone, and the water extracts yielded mainly chlorogenic acid, salvianolic acid B, luteolin-7-O-rutinoside, and rosmarinic acid. The water extracts exhibited significant nematicidal activity against Meloidogyne incognita , and the EC50/72h values were calculated at 1005, 745, and 300 mg/L for M. × piperita, M. pulegium, and M. spicata, respectively. Only the essential oil from M. spicata showed a nematicidal activity with an EC50/72h of 358 mg/L. Interestingly, menthofuran and carvone showed EC50/48h values of 127 and 730 mg/L, respectively. On the other hand, salicylic acid, isolated in the aqueous extracts, exhibited EC50 values at 24 and 48 h of 298 ± 92 and 288 ± 79 mg/L, respectively.

  17. Evaluation of Dry Ice as a Potential Cryonematicide for Meloidogyne incognita in Soil

    PubMed Central

    Wergin, William P.; Yaklich, Robert W.; Chitwood, David J.; Erbe, Eric F.

    1999-01-01

    Solid CO₂ (dry ice) was added to pots containing soil that was infested either with eggs of the root-knot nematode, Meloidogyne incognita, or with tomato (Lycopersicon esculentum 'Rutgers') root fragments that were infected with various stages of the nematode. Two hours after dry ice was added, thermocouples in the soil recorded temperatures ranging from -15 °C to -59 °C. One day after treatment with the dry ice, the temperature of the soil was allowed to equilibrate with that of the greenhouse, and susceptible tomato seedlings were planted in pots containing infested soil treated or untreated (controls) with dry ice. After 5 weeks, roots were removed from the pots and nematode eggs were extracted and counted. Plants grown in soil infested with eggs and receiving dry ice treatment had less than 1% of the eggs found in the controls; plants from soil infested with root fragments and receiving dry ice treatment had less than 4% of the eggs found in controls. Dry ice used to lower soil temperature may have potential as a cryonematicide. PMID:19270918

  18. Production and Partial Characterization of Stylet Exudate from Adult Females of Meloidogyne incognita

    PubMed Central

    Veech, J. A.; Starr, J. L.; Nordgren, R. M.

    1987-01-01

    Adult females of Meloidogyne incognita were excised from tomato roots and incubated in 0.04 M phosphate buffered saline, pH 7.4 for 18-72 hours to allow accumulation of stylet exudate. Twenty-four percent of the females produced exudate during the initial 18-hour incubation period; 70% of those females producing exudate initially produced additional exudate during the subsequent 54-hour incubation period. Analysis of exudate by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed the presence of at least nine major protein bands. Differential staining with silver and Coomassie Brilliant Blue G-250 stains indicated that three of the bands were glycoproteins. Upon acid hydrolysis, 14 amino acids were detected in the stylet exudate. The basic amino acids lysine, histidine, and arginine comprised 21.8% of the total amino acids detected. No peroxidase activity was detected in the stylet exudates. Data presented extend and generally confirm prior work on the chemical composition of stylet exudate. PMID:19290172

  19. Evaluation of Dry Ice as a Potential Cryonematicide for Meloidogyne incognita in Soil.

    PubMed

    Wergin, W P; Yaklich, R W; Chitwood, D J; Erbe, E F

    1999-12-01

    Solid CO (dry ice) was added to pots containing soil that was infested either with eggs of the root-knot nematode, Meloidogyne incognita, or with tomato (Lycopersicon esculentum 'Rutgers') root fragments that were infected with various stages of the nematode. Two hours after dry ice was added, thermocouples in the soil recorded temperatures ranging from -15 degrees C to -59 degrees C. One day after treatment with the dry ice, the temperature of the soil was allowed to equilibrate with that of the greenhouse, and susceptible tomato seedlings were planted in pots containing infested soil treated or untreated (controls) with dry ice. After 5 weeks, roots were removed from the pots and nematode eggs were extracted and counted. Plants grown in soil infested with eggs and receiving dry ice treatment had less than 1% of the eggs found in the controls; plants from soil infested with root fragments and receiving dry ice treatment had less than 4% of the eggs found in controls. Dry ice used to lower soil temperature may have potential as a cryonematicide.

  20. Invasion of Tomato Roots and Reproduction of Meloidogyne incognita as Affected by Raw Sewage Sludge

    PubMed Central

    Castagnone-Sereno, Philippe; Kermarrec, Alain

    1991-01-01

    The antagonistic effects of raw sewage sludge on infection of tomato by Meloidogyne incognita were tested in greenhouse pot experiments. Sludge was mixed with the soil or added on its surface before and after inoculation of tomato plants with nematode eggs. Juvenile penetration was determined 1 and 10 days after inoculation, and 6 weeks later root systems were assessed for nematode reproduction. Fewer juveniles penetrated roots in pots with sludge added to the soil than in unamended control pots. In both experiments, roots were severely galled despite a significant reduction in gall ratings in amended relative to unamended soils. Egg production in treated soil was less (P = 0.05) than in control pots, regardless of whether sludge was incorporated or added 1 day before or after inoculation. In treated pots, RF values (final egg number/inoculation egg number) were strongly reduced. The toxic effects observed on the parasite may result from the ammoniacal nitrogen released in the soil within 7 days after treatment, associated with possible poor host suitability of tomatoes grown in amended substrate and short-lasting compound(s) active after root invasion. PMID:19283192

  1. Influence of Environmental Factors on the Hatch and Survival of Meloidogyne incognita

    PubMed Central

    Goodell, P. B.; Ferris, H.

    1989-01-01

    The influence of soil temperature and moisture on Meloidogyne incognita (Kofoid and White) Chitwood was examined in relation to hatching and survival of second-stage juveniles (J2). Nematodes were cultured on cotton (Gossypium hirsutum L. cv. Acala SJ2) under field conditions to provide populations similar to those found in the field in late autumn. Egg masses were placed in a temperature range (9-12 C and 21 C), and hatch was measured over a period equivalent to 20 degree days > 10 C (DD10). Hatch occurred below the reported 18 C activity threshold, was restricted below 12 C, and was inhibited below 10 C. Soil moisture influence on hatch was measured by placing egg masses in Hesperia sandy loam and subjecting them to suction pressures ranging from -1.1 bars to -4 .5 bars. Suction potentials of less than -2 bars reduced hatch and less than -3 bars inhibited hatch. J2 were placed in sandy loam soil with soil moisture near field capacity, and their motility was measured over a period of 500 DD10. In the absence of a host, more than 90% of J2 became nonmotile over this period. PMID:19287616

  2. Preferential expression of a plant cystatin at nematode feeding sites confers resistance to Meloidogyne incognita and Globodera pallida.

    PubMed

    Lilley, Catherine J; Urwin, Peter E; Johnston, Katherine A; Atkinson, Howard J

    2004-01-01

    The expression patterns of three promoters preferentially active in the roots of Arabidopsis thaliana have been investigated in transgenic potato plants in response to plant parasitic nematode infection. Promoter regions from the three genes, TUB-1, ARSK1 and RPL16A were linked to the GUS reporter gene and histochemical staining was used to localize expression in potato roots in response to infection with both the potato cyst nematode, Globodera pallida and the root-knot nematode, Meloidogyne incognita. All three promoters directed GUS expression chiefly in root tissue and were strongly up-regulated in the galls induced by feeding M. incognita. Less activity was associated with the syncytial feeding cells of the cyst nematode, although the ARSK1 promoter was highly active in the syncytia of G. pallida infecting soil grown plants. Transgenic potato lines that expressed the cystatin OcIDeltaD86 under the control of the three promoters were evaluated for resistance against Globodera sp. in a field trial and against M. incognita in containment. Resistance to Globodera of 70 +/- 4% was achieved with the best line using the ARSK1 promoter with no associated yield penalty. The highest level of partial resistance achieved against M. incognita was 67 +/- 9% using the TUB-1 promoter. In both cases this was comparable to the level of resistance achieved using the constitutive cauliflower mosaic virus 35S (CaMV35S) promoter. The results establish the potential for limiting transgene expression in crop plants whilst maintaining efficacy of the nematode defence.

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

    PubMed Central

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

    2017-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

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

  5. Nematocidal flavone-C-glycosides against the root-knot nematode (Meloidogyne incognita) from Arisaema erubescens tubers.

    PubMed

    Du, Shu Shan; Zhang, Hai Ming; Bai, Chun Qi; Wang, Cheng Fang; Liu, Qi Zhi; Liu, Zhi Long; Wang, Yong Yan; Deng, Zhi Wei

    2011-06-20

    A screening of several Chinese medicinal herbs for nematicidal properties showed that Arisaema erubescens (Wall.) Schott tubers possessed significant nematicidal activity against the root-knot nematode (Meloidogyne incognita). From the ethanol extract, two nematicidal flavone-C-glycosides were isolated by bioassay-guided fractionation. The compounds were identified as schaftoside and isoschaftoside on the basis of their phytochemical and spectral data. Schaftoside and isoschaftoside possessed strong nematicidal activity against M. incognita (LC(50) = 114.66 μg/mL and 323.09 μg/mL, respectively) while the crude extract of A. erubescens exhibited nematicidal activity against the root-knot nematode with a LC(50) value of 258.11 μg/mL.

  6. Repulsion of Meloidogyne incognita by Alginate Pellets Containing Hyphae of Monacrosporium cionopagum, M. ellipsosporum, or Hirsutella rhossiliensis.

    PubMed

    Robinson, A F; Jaffee, B A

    1996-06-01

    The responses of second-stage juveniles (J2) of Meloidogyne incognita race 3 to calcium alginate pellets containing hyphae of the nematophagous fungi Monacrosporiura cionopagum, M. ellipsosporum, and Hirsutella rhossiliensis were examined using cylinders (38-mm-diam., 40 or 72 mm long) of sand (94% <250-mum particle size). Sand was wetted with a synthetic soil solution (10% moisture, 0.06 bar water potential). A layer of 10 or 20 pellets was placed 4 or 20 mm from one end of the cylinder. After 3, 5, or 13 days, J2 were put on both ends, on one end, or in the center; J2 were extracted from 8-ram-thick sections 1 or 2 days later. All three fungal pellets were repellent; pellets without fungi were not. Aqueous extracts of all pellets and of sand in which fungal pellets had been incubated were repellent, but acetone extracts redissolved in water were not. Injection of CO (20 mul/minute) into the pellet layer attracted J2 and increased fungal-induced mortality. In vials containing four randomly positioned pellets and 17 cm(3) of sand or loamy sand, the three fungi suppressed the invasion of cabbage roots by M. javanica J2. Counts of healthy and parasitized nematodes observed in roots or extracted from soil indicated that, in the vial assay, the failure of J2 to penetrate roots resulted primarily from parasitism rather than repulsion. Data were similar whether fungal inoculum consisted of pelletized hyphae or fungal-colonized Steinernema glaseri. Thus, the results indicate that nematode attractants and repellents can have major or negligible effects on the biological control efficacy of pelletized nematophagous fungi. Factors that might influence the importance of substances released by the pellets include the strength, geometry, and duration of gradients; pellet degradation by soil microflora; the nematode species involved; and attractants released by roots.

  7. Solanum torvum responses to the root-knot nematode Meloidogyne incognita

    PubMed Central

    2013-01-01

    Background Solanum torvum Sw is worldwide employed as rootstock for eggplant cultivation because of its vigour and resistance/tolerance to the most serious soil-borne diseases as bacterial, fungal wilts and root-knot nematodes. The little information on Solanum torvum (hereafter Torvum) resistance mechanisms, is mostly attributable to the lack of genomic tools (e.g. dedicated microarray) as well as to the paucity of database information limiting high-throughput expression studies in Torvum. Results As a first step towards transcriptome profiling of Torvum inoculated with the nematode M. incognita, we built a Torvum 3’ transcript catalogue. One-quarter of a 454 full run resulted in 205,591 quality-filtered reads. De novo assembly yielded 24,922 contigs and 11,875 singletons. Similarity searches of the S. torvum transcript tags catalogue produced 12,344 annotations. A 30,0000 features custom combimatrix chip was then designed and microarray hybridizations were conducted for both control and 14 dpi (day post inoculation) with Meloidogyne incognita-infected roots samples resulting in 390 differentially expressed genes (DEG). We also tested the chip with samples from the phylogenetically-related nematode-susceptible eggplant species Solanum melongena. An in-silico validation strategy was developed based on assessment of sequence similarity among Torvum probes and eggplant expressed sequences available in public repositories. GO term enrichment analyses with the 390 Torvum DEG revealed enhancement of several processes as chitin catabolism and sesquiterpenoids biosynthesis, while no GO term enrichment was found with eggplant DEG. The genes identified from S. torvum catalogue, bearing high similarity to known nematode resistance genes, were further investigated in view of their potential role in the nematode resistance mechanism. Conclusions By combining 454 pyrosequencing and microarray technology we were able to conduct a cost-effective global transcriptome profiling

  8. Resistance to Southern Root-knot Nematode (Meloidogyne incognita) in Wild Watermelon (Citrullus lanatus var. citroides).

    PubMed

    Thies, Judy A; Ariss, Jennifer J; Kousik, Chandrasekar S; Hassell, Richard L; Levi, Amnon

    2016-03-01

    Southern root-knot nematode (RKN, Meloidogyne incognita) is a serious pest of cultivated watermelon (Citrullus lanatus var. lanatus) in southern regions of the United States and no resistance is known to exist in commercial watermelon cultivars. Wild watermelon relatives (Citrullus lanatus var. citroides) have been shown in greenhouse studies to possess varying degrees of resistance to RKN species. Experiments were conducted over 2 yr to assess resistance of southern RKN in C. lanatus var. citroides accessions from the U.S. Watermelon Plant Introduction Collection in an artificially infested field site at the U.S. Vegetable Laboratory in Charleston, SC. In the first study (2006), 19 accessions of C. lanatus var. citroides were compared with reference entries of Citrullus colocynthis and C. lanatus var. lanatus. Of the wild watermelon accessions, two entries exhibited significantly less galling than all other entries. Five of the best performing C. lanatus var. citroides accessions were evaluated with and without nematicide at the same field site in 2007. Citrullus lanatus var. citroides accessions performed better than C. lanatus var. lanatus and C. colocynthis. Overall, most entries of C. lanatus var. citroides performed similarly with and without nematicide treatment in regard to root galling, visible egg masses, vine vigor, and root mass. In both years of field evaluations, most C. lanatus var. citroides accessions showed lesser degrees of nematode reproduction and higher vigor and root mass than C. colocynthis and C. lanatus var. lanatus. The results of these two field evaluations suggest that wild watermelon populations may be useful sources of resistance to southern RKN.

  9. Resistance to Southern Root-knot Nematode (Meloidogyne incognita) in Wild Watermelon (Citrullus lanatus var. citroides)

    PubMed Central

    Thies, Judy A.; Ariss, Jennifer J.; Kousik, Chandrasekar S.; Hassell, Richard L.; Levi, Amnon

    2016-01-01

    Southern root-knot nematode (RKN, Meloidogyne incognita) is a serious pest of cultivated watermelon (Citrullus lanatus var. lanatus) in southern regions of the United States and no resistance is known to exist in commercial watermelon cultivars. Wild watermelon relatives (Citrullus lanatus var. citroides) have been shown in greenhouse studies to possess varying degrees of resistance to RKN species. Experiments were conducted over 2 yr to assess resistance of southern RKN in C. lanatus var. citroides accessions from the U.S. Watermelon Plant Introduction Collection in an artificially infested field site at the U.S. Vegetable Laboratory in Charleston, SC. In the first study (2006), 19 accessions of C. lanatus var. citroides were compared with reference entries of Citrullus colocynthis and C. lanatus var. lanatus. Of the wild watermelon accessions, two entries exhibited significantly less galling than all other entries. Five of the best performing C. lanatus var. citroides accessions were evaluated with and without nematicide at the same field site in 2007. Citrullus lanatus var. citroides accessions performed better than C. lanatus var. lanatus and C. colocynthis. Overall, most entries of C. lanatus var. citroides performed similarly with and without nematicide treatment in regard to root galling, visible egg masses, vine vigor, and root mass. In both years of field evaluations, most C. lanatus var. citroides accessions showed lesser degrees of nematode reproduction and higher vigor and root mass than C. colocynthis and C. lanatus var. lanatus. The results of these two field evaluations suggest that wild watermelon populations may be useful sources of resistance to southern RKN. PMID:27168648

  10. Recovery and Longevity of Egg Masses of Meloidogyne incognita during Simulated Winter Survival

    PubMed Central

    Starr, J. L.

    1993-01-01

    Effects of soil matrix potential on longevity of egg masses of Meloidogyne incognita were determined during simulated winter conditions. Egg masses were recovered from isolated root fragments incubated in field soil at matrix potentials of -0.1, -0.3, -1.0, and -4.0 bars throughout winter survival periods of 10 weeks for tomato roots and 12 weeks for cotton roots. Egg masses were more superficial on cotton roots than on tomato roots and were more easily dislodged from cotton roots during recovery of root fragments by elutriation. The rate of decline in numbers of eggs and J2 per egg mass was greater in wet as compared to dry soils (P = 0.01), with the relationship between numbers of eggs and J2 per egg mass and time being best described by quadratic models. Percentage hatch of recovered eggs declines linearly with time at soil matrix potentials of -0.1 and -0.3 bars, but at -1.0 and -4.0 bars the percentage hatch of recovered eggs increased before declining. Effects of soil matrix potential on numbers of eggs per egg mass and percentage hatch of recovered eggs were consistent with previous reports that low soil moisture inhibits egg hatch before affecting egg development. Estimations of egg population densities during winter survival periods will be affected by ability to recover infected root fragments from the soil without dislodging associated egg masses. There is a need for procedures for extraction of egg masses not attached to roots from the soil. PMID:19279764

  11. Nematicidal Activity of the Volatilome of Eruca sativa on Meloidogyne incognita.

    PubMed

    Aissani, Nadhem; Urgeghe, Pietro Paolo; Oplos, Chrisostomos; Saba, Marco; Tocco, Graziella; Petretto, Giacomo Luigi; Eloh, Kodjo; Menkissoglu-Spiroudi, Urania; Ntalli, Nikoletta; Caboni, Pierluigi

    2015-07-15

    Research on new pesticides based on plant extracts, aimed at the development of nontoxic formulates, has recently gained increased interest. This study investigated the use of the volatilome of rucola (Eruca sativa) as a powerful natural nematicidal agent against the root-knot nematode, Meloidogyne incognita. Analysis of the composition of the volatilome, using GC-MS-SPME, showed that the compound (Z)-3-hexenyl acetate was the most abundant, followed by (Z)-3-hexen-1-ol and erucin, with relative percentages of 22.7 ± 1.6, 15.9 ± 2.3, and 8.6 ± 1.3, respectively. Testing of the nematicidal activity of rucola volatile compounds revealed that erucin, pentyl isothiocyanate, hexyl isothiocyanate, (E)-2-hexenal, 2-ethylfuran, and methyl thiocyanate were the most active with EC50 values of 3.2 ± 1.7, 11.1 ± 5.0, 11.3 ± 2.6, 15.0 ± 3.3, 16.0 ± 5.0, and 18.1 ± 0.6 mg/L, respectively, after 24 h of incubation. Moreover, the nematicidal activity of fresh rucola used as soil amendant in a containerized culture of tomato decreased the nematode infection in a dose-response manner (EC50 = 20.03 mg/g) and plant growth was improved. On the basis of these results, E. sativa can be considered as a promising companion plant in intercropping strategies for tomato growers to control root-knot nematodes.

  12. Overexpression of MIC-3 indicates a direct role for the MIC gene family in mediating Upland cotton (Gossypium hirsutum) resistance to root-knot nematode (Meloidogyne incognita)

    USDA-ARS?s Scientific Manuscript database

    Major quantitative trait loci (QTL) have been mapped to Upland cotton (Gossypium hirsutum L.) chromosomes 11 and 14 that govern the highly resistant phenotype in response to infection by root-knot nematode (RKN; Meloidogyne incognita Chitwood & White); however, nearly nothing is known regarding the ...

  13. In vitro proteolysis of nematode FLPs by preparations from the free-living nematode Panagrellus redivivus and two plant-parasitic nematodes (Heterodera glycines and Meloidogyne incognita)

    USDA-ARS?s Scientific Manuscript database

    Proteolytic activities in extracts from three nematodes, the plant parasites Heterodera glycines and Meloidogyne incognita, and the free-living Panagrellus redivivus, were surveyed for substrate preferences using a battery of seven FRET-modified peptide substrates, all derived from members of the la...

  14. Sampling techniques and detection methods for developing risk assessments for root-knot nematode (Meloidogyne incognita) on lima bean (Phaseolus lunatus) in the Mid-Atlantic region

    USDA-ARS?s Scientific Manuscript database

    Lima bean, Phaseolus lunatus, is a cornerstone crop in the Mid-Atlantic region and Meloidogyne incognita, the southern root knot nematode (RKN), causes significant yield loss. The RKN has become more pervasive as toxic nematicides have been removed from the market, and risk evaluation research is ne...

  15. Inheritance of resistance to Meloidogyne incognita race 2 in the hot pepper cultivar Carolina Cayenne (Capsicum annuum L.).

    PubMed

    de Souza-Sobrinho, Fausto; Maluf, Wilson Roberto; Gomes, Luiz A A; Campos, Vicente Paulo

    2002-09-30

    Root-knot nematodes of the genus Meloidogyne are important pathogens affecting vegetable crop production in Brazil and worldwide. The pepper species Capsicum annuum includes both hot and sweet peppers; very little emphasis has been placed on breeding sweet peppers for nematode resistance. We report on the inheritance of resistance to Meloidogyne incognita (Kofoid & White) Chitwood race 2 in the hot pepper cultivar Carolina Cayenne. The hot pepper cv. Carolina Cayenne was used as seed parent and the sweet pepper cv. Agronômico-8 was used as pollen parent to obtain the F(1) and F(2) generations and the backcross generations BC(11) and BC(12). The plants were inoculated with M. incognita race 2 at a rate of 60 eggs/ml of substrate and, after a suitable incubation period, the numbers of root galls and egg masses per root system were evaluated on each plant. Broad- (0.77 and 0.72) and narrow-sense (0.77 and 0.63) heritability estimates were high for both root galls and egg masses, respectively. The mean degree of dominance was estimated as 0.29 and 0.25 for numbers of galls and egg masses, respectively; these estimates were not significantly different from 0, indicating a predominantly additive gene action. The results were consistent with a hypothesis of monogenic resistance in Carolina Cayenne.

  16. Impact of direct and indirect application of rising furfural concentrations on viability, infectivity and reproduction of the root-knot nematode, Meloidogyne incognita in Pisum sativum.

    PubMed

    Abdelnabby, Hazem; Wang, Yunhe; Xiao, Xueqiong; Wang, Gaofeng; Yang, Fan; Xiao, Yannong

    2016-07-01

    The gradual withdraw of several broadly used nematicides from market has enhanced the need to develop sustainable and eco-friendly alternatives with nematicidal properties. Furfural is one of the promising alternatives to fill this need. Baseline information about the impact of furfural on egg hatch, penetration potential and ultrastructure of nematode is lacking. In this study, the reagent-grade (purity ≥ 99.0%) of furfural was applied against Meloidogyne incognita. In vitro tests showed gradual reduction in either the rate of egg hatch or second stage juvenile (J2) viability of M. incognita when immersed in concentrations ranging from 0 to 10.0 μl/ml furfural. The mean EC50 for J2 and egg hatch was 0.37 and 0.27 μl/ml furfural, respectively. Furfural, even at low concentrations, resulted in a considerable suppression in egg hatch. Hatch was <5% after 8 days at 0.63 μl/ml furfural. The same furfural concentrations after 12 h caused 57.25% loss of viability in J2. Moreover, the penetration rate of juveniles to pea roots was suppressed when furfural was even applied at low rates. In pot experiments, furfural was applied as liquid (direct) or vapor (indirect) treatments at rates of 0-1.5 ml/kg soil. Significant reduction in galling, egg production and population density of M. incognita observed when furfural was applied at rates >0.2 ml/kg soil. No adverse effect was detected on plants or free-living nematodes as a result of furfural application. Liquid furfural proved to have superior juvenile-suppressive effect whereas its vapor has such superiority against eggs. Scanning electron microscope (SEM) study showed irregular appearance of the body surface accompanied with some cuticle disfigurement of furfural-treated juveniles. These results indicated that furfural can adversely affect egg hatch, juvenile viability, penetration potential and ultrastructure of M. incognita. Furfural may therefore be of a considerable potential as an appropriate

  17. Host Transcriptional Profiling at Early and Later Stages of the Compatible Interaction Between Phaseolus vulgaris and Meloidogyne incognita.

    PubMed

    Santini, Luciane; Munhoz, Carla de Freitas; Bonfim, Mauro Ferreira; Brandão, Marcelo Mendes; Inomoto, Mário Massayuki; Vieira, Maria Lucia Carneiro

    2016-03-01

    The root-knot nematode (Meloidogyne incognita) is one of most devastating pathogens that attack the common bean crop. Although there is evidence that some cultivars have race-specific resistance against M. incognita, these resistance sources have not proved effective, and nematodes are able to circumvent the host's defense system. We constructed RNA-seq based libraries and used a high-throughput sequencing platform to analyze the plant responses to M. incognita. Assessments were performed at 4 and 10 days after inoculation corresponding to the stages of nematode penetration and giant cell development, respectively. Large-scale transcript mapping to the common bean reference genome (G19833) resulted in the identification of 27,195 unigenes. Of these, 797 host genes were found to be differentially expressed. The functional annotation results confirm the complex interplay between abiotic and biotic stress signaling pathways. High expression levels of the wounding-responsive genes were observed over the interaction. At early response, an overexpression of the N gene, a TIR-NBS-LRR resistance gene, was understood as a host attempt to overcome the pathogen attack. However, the repression of heat shock proteins resulted in a lack of reactive oxygen species accumulation and absence of a hypersensitive response. Furthermore, the host basal response was broken by the repression of the ethylene/jasmonate pathway later in the response, resulting in a continuous compatible process with consequent plant susceptibility.

  18. Effect of mowing cotton stalks and preventing plant re-growth on post-harvest reproduction of Meloidogyne incognita.

    PubMed

    Lu, Ping; Davis, Richard F; Kemerait, Robert C

    2010-06-01

    The southern root-knot nematode (Meloidogyne incognita) is a major parasite of cotton in the U.S., and management tactics for this nematode attempt to minimize population levels. We compared three post-harvest practices for their ability to reduce nematode population levels in the field, thereby reducing initial nematode population for the next year's crop. The three practices tested were: 1) chemical defoliation before harvest plus cutting cotton stalks after harvest, 2) chemical defoliation plus applying a herbicide to kill plants prior to cutting the stalks, and 3) chemical defoliation without cutting stalks. Experiments were conducted in both the greenhouse and in the field. The greenhouse experiments demonstrated that M. incognita reproduction (measured as egg counts and root gall rating indices) was significantly greater when stalks were not cut. Cutting stalks plus applying herbicide to kill cotton roots did not significantly reduce nematode reproduction compared to cutting stalks alone. In field experiments, cutting stalks reduced egg populations and root galling compared to defoliation without stalk cutting. In a greenhouse bioassay which used soil from the field plots, plants grown in soil from the defoliation only treatment had greater root gall ratings and egg counts than in the stalk cutting plus herbicide treatment. Therefore, we conclude that cutting cotton stalks immediately after harvest effectively reduces M. incognita reproduction, and may lead to a lower initial population density of this nematode in the following year.

  19. Efficacy Evaluation of Fungus Syncephalastrum racemosum and Nematicide Avermectin against the Root-Knot Nematode Meloidogyne incognita on Cucumber

    PubMed Central

    Huang, Wen-Kun; Sun, Jian-Hua; Cui, Jiang-Kuan; Wang, Gang-Feng; Kong, Ling-An; Peng, Huan; Chen, Shu-Long; Peng, De-Liang

    2014-01-01

    The root-knot nematode (RKN) is one of the most damaging agricultural pests.Effective biological control is need for controlling this destructive pathogen in organic farming system. During October 2010 to 2011, the nematicidal effects of the Syncephalastrum racemosum fungus and the nematicide, avermectin, alone or combined were tested against the RKN (Meloidogyne incognita) on cucumber under pot and field condition in China. Under pot conditions, the application of S. racemosum alone or combined with avermectin significantly increased the plant vigor index by 31.4% and 10.9%, respectively compared to the M. incognita-inoculated control. However, treatment with avermectin alone did not significantly affect the plant vigor index. All treatments reduced the number of root galls and juvenile nematodes compared to the untreated control. Under greenhouse conditions, all treatments reduced the disease severity and enhanced fruit yield compared to the untreated control. Fewer nematodes infecting plant roots were observed after treatment with avermectin alone, S. racemosum alone or their combination compared to the M. incognita-inoculated control. Among all the treatments, application of avermectin or S. racemosum combined with avermectin was more effective than the S. racemosum treatment. Our results showed that application of S. racemosum combined with avermectin not only reduced the nematode number and plant disease severity but also enhanced plant vigor and yield. The results indicated that the combination of S. racemosum with avermectin could be an effective biological component in integrated management of RKN on cucumber. PMID:24586982

  20. Multiplex PCR for the simultaneous identification and detection of Meloidogyne incognita, M. enterolobii, and M. javanica using DNA extracted directly from individual galls.

    PubMed

    Hu, M X; Zhuo, K; Liao, J L

    2011-11-01

    Meloidogyne incognita, M. enterolobii, and M. javanica are the most widespread species of root-knot nematodes in South China, affecting many economically important crops, ornamental plants, and fruit trees. In this study, one pair of Meloidogyne universal primers was designed and three pairs of species-specific primers were employed successfully to rapidly detect and identify M. incognita, M. enterolobii, and M. javanica by multiplex polymerase chain reaction (PCR) using DNA extracted from individual galls. Multiplex PCR from all M. incognita, M. enterolobii, and M. javanica isolates generated two fragments of ≈500 and 1,000, 500 and 200, and 500 and 700 bp, respectively. The 500-bp fragment is the internal positive control fragment of rDNA 28S D2/D3 resulting from the use of the universal primers. Other Meloidogyne spp. included in this study generated only one fragment of ≈500 bp in size. Using this approach, M. incognita, M. enterolobii, and M. javanica were identified and detected using DNA extracted directly from individual galls containing the Meloidogyne spp. at various stages of their life cycle. Moreover, the percentage of positive PCR amplification increased with nematode development and detection was usually easy after the late stage of the second-stage juvenile. The protocol was applied to galls from naturally infested roots and the results were found to be fast, sensitive, robust, and accurate. This present study is the first to provide a definitive diagnostic tool for M. incognita, M. enterolobii, and M. javanica using DNA extracted directly from individual galls using a one-step multiplex PCR technique.

  1. Elucidating the molecular bases of epigenetic inheritance in non-model invertebrates: the case of the root-knot nematode Meloidogyne incognita

    PubMed Central

    Perfus-Barbeoch, Laetitia; Castagnone-Sereno, Philippe; Reichelt, Michael; Fneich, Sara; Roquis, David; Pratx, Loris; Cosseau, Céline; Grunau, Christoph; Abad, Pierre

    2014-01-01

    Root-knot nematodes of the genus Meloidogyne are biotrophic plant parasites that exhibit different life cycles and reproduction modes, ranging from classical amphimixis to obligatory mitotic parthenogenesis (apomixis), depending on the species. Meloidogyne incognita, an apomictic species, exhibits a worldwide distribution and a wide host range affecting more than 3000 plant species. Furthermore, evidences suggest that apomixis does not prevent M. incognita from adapting to its environment in contrast to what is expected from mitotic parthenogenesis that should theoretically produce clonal progenies. This raises questions about mechanisms of genome plasticity leading to genetic variation and adaptive evolution in apomictic animals. We reasoned that epigenetic mechanisms might in part be responsible for the generation of phenotypic variants that provide potential for rapid adaptation. We established therefore a pipeline to investigate the principal carriers of epigenetic information, DNA methylation and post-translational histone modifications. Even if M. incognita possesses the epigenetic machinery i.e., chromatin modifying enzymes, 5-methyl-cytosine and 5-hydroxy-methyl-cytosine content is absent or very weak. In contrast, we demonstrated that the canonical histone modifications are present and chromatin shows typical nucleosome structure. This work is the first characterization of carriers of epigenetic information in M. incognita and constitutes a preamble to further investigate if M. incognita development and its adaptation to plant hosts are under epigenetic control. Our pipeline should allow performing similar types of studies in any non-model organism. PMID:24936189

  2. Image Analysis of the Growth of Globodera pallida and Meloidogyne incognita on Transgenic Tomato Roots Expressing Cystatins

    PubMed Central

    Atkinson, H. J.; Urwin, P. E.; Clarke, M. C.; McPherson, M. J.

    1996-01-01

    An approach based on image analysis that enables rapid collection and analysis of nematode size and shape during growth is reported. This technique has been applied to assess Meloidogyne incognita and Globodera pallida during their development over 35 and 42 days, respectively, on transgenic tomato roots expressing the wild-type rice cystatin Oc-I or an engineered variant, Oc-IAD86. Morphometric values were established that subdivided enlarged saccate females from other life stages. Analysis of this data subset indicates that the size of females and the frequency with which they parasitize roots expressing a cystatin are reduced. Results also demonstrate that cystatins can influence the growth of G. pallida prior to the adult stage. Similar image analysis procedures should be generally applicable to the study of host status or erivironmental factors that influence growth rates of plant-parasitic nematodes. PMID:19277136

  3. Management of Meloidogyne incognita with tall fescue grass rotations prior to peach orchard establishment

    USDA-ARS?s Scientific Manuscript database

    Root-knot nematodes (Meloidogyne spp.) are important pests of peach in the USA. Preplant fumigant nematicides have been used to control Meloidogyne spp. associated with Southeastern peach production. Unfortunately, growers have increasingly faced economic challenges, making it difficult for them t...

  4. Preplanting tall fescue grass for controlling Meloidogyne incognita in a young peach orchard

    USDA-ARS?s Scientific Manuscript database

    Preplant fumigant nematicides have traditionally been used to control Meloidogyne spp. in peach in the southeastern United States. The current preplant nematicides recommended for managing Meloidogyne spp. in peach include the soil fumigants, 1,3-dichloropropene and metam sodium. Because the econo...

  5. Volatile Substances Produced by Fusarium oxysporum from Coffee Rhizosphere and Other Microbes affect Meloidogyne incognita and Arthrobotrys conoides.

    PubMed

    Freire, E S; Campos, V P; Pinho, R S C; Oliveira, D F; Faria, M R; Pohlit, A M; Noberto, N P; Rezende, E L; Pfenning, L H; Silva, J R C

    2012-12-01

    Microorganisms produce volatile organic compounds (VOCs) which mediate interactions with other organisms and may be the basis for the development of new methods to control plant-parasitic nematodes that damage coffee plants. In the present work, 35 fungal isolates were isolated from coffee plant rhizosphere, Meloidogyne exigua eggs and egg masses. Most of the fungal isolates belonged to the genus Fusarium and presented in vitro antagonism classified as mutual exclusion and parasitism against the nematode-predator fungus Arthrobotrys conoides (isolated from coffee roots). These results and the stronger activity of VOCs against this fungus by 12 endophytic bacteria may account for the failure of A. conoides to reduce plant-parasitic nematodes in coffee fields. VOCs from 13 fungal isolates caused more than 40% immobility to Meloidogyne incognita second stage juveniles (J2), and those of three isolates (two Fusarium oxysporum isolates and an F. solani isolate) also led to 88-96% J2 mortality. M. incognita J2 infectivity decreased as a function of increased exposure time to F. oxysporum isolate 21 VOCs. Gas chromatography-mass spectrometry (GC-MS) analysis lead to the detection of 38 VOCs produced by F. oxysporum is. 21 culture. Only five were present in amounts above 1% of the total: dioctyl disulfide (it may also be 2-propyldecan-1-ol or 1-(2-hydroxyethoxy) tridecane); caryophyllene; 4-methyl-2,6-di-tert-butylphenol; and acoradiene. One of them was not identified. Volatiles toxic to nematodes make a difference among interacting microorganisms in coffee rhizosphere defining an additional attribute of a biocontrol agent against plant-parasitic nematodes.

  6. Volatile Substances Produced by Fusarium oxysporum from Coffee Rhizosphere and Other Microbes affect Meloidogyne incognita and Arthrobotrys conoides

    PubMed Central

    Freire, E. S.; Campos, V. P.; Pinho, R. S. C.; Oliveira, D. F.; Faria, M. R.; Pohlit, A. M.; Noberto, N. P.; Rezende, E. L.; Pfenning, L. H.; Silva, J. R. C.

    2012-01-01

    Microorganisms produce volatile organic compounds (VOCs) which mediate interactions with other organisms and may be the basis for the development of new methods to control plant-parasitic nematodes that damage coffee plants. In the present work, 35 fungal isolates were isolated from coffee plant rhizosphere, Meloidogyne exigua eggs and egg masses. Most of the fungal isolates belonged to the genus Fusarium and presented in vitro antagonism classified as mutual exclusion and parasitism against the nematode-predator fungus Arthrobotrys conoides (isolated from coffee roots). These results and the stronger activity of VOCs against this fungus by 12 endophytic bacteria may account for the failure of A. conoides to reduce plant-parasitic nematodes in coffee fields. VOCs from 13 fungal isolates caused more than 40% immobility to Meloidogyne incognita second stage juveniles (J2), and those of three isolates (two Fusarium oxysporum isolates and an F. solani isolate) also led to 88-96% J2 mortality. M. incognita J2 infectivity decreased as a function of increased exposure time to F. oxysporum isolate 21 VOCs. Gas chromatography-mass spectrometry (GC-MS) analysis lead to the detection of 38 VOCs produced by F. oxysporum is. 21 culture. Only five were present in amounts above 1% of the total: dioctyl disulfide (it may also be 2-propyldecan-1-ol or 1-(2-hydroxyethoxy) tridecane); caryophyllene; 4-methyl-2,6-di-tert-butylphenol; and acoradiene. One of them was not identified. Volatiles toxic to nematodes make a difference among interacting microorganisms in coffee rhizosphere defining an additional attribute of a biocontrol agent against plant-parasitic nematodes. PMID:23482720

  7. Differentiation of Meloidogyne incognita and M. arenaria novel resistance phenotypes in Lycopersicon peruvianum and derived bridge-lines.

    PubMed

    Veremis, J C; Roberts, P A

    1996-10-01

    Lycopersicon peruvianum PI 270435 clone 2R2 and PI 126443 clone 1MH were crossed reciprocally with three L. esculentum-L. peruvianum bridge-lines. The incongruity barrier between the two plant species was overcome; F1 progeny were obtained from crosses between four parental combinations without embryo-rescue culture. Hybridity was confirmed by leaf and flower morphology and by the production of nematode-resistant F1 progeny on homozygous susceptible parents. Clones of the five F1 bridgeline hybrids were highly resistant to Mi-avirulent root-knot nematode (Meloidogyne incognita) at both 25°C and 30°C soil temperatures. However, only clones from PI 270435-3MH and PI 126443-1MH, and hybrids from PI 126443-1MH, were resistant to Mi-virulent M. incognita isolates at high soil temperature. Clones and hybrids from PI 270435-2R2 were not resistant to two Mi-virulent M. incognita isolates at high soil temperature. A source of heat-stable resistance was identified in bridge-line EPP-2, and was found to be derived from L. peruvianum LA 1708. Accessions of the L. peruvianum 'Maranon races', LA 1708 and LA 2172, and bridge-line EPP-2, segregated for heat-stable resistance to Mi-avirulent M. incognita, but were susceptible to Mi-virulent M. incognita isolates. Clone LA 1708-I conferred heat-stable resistance to M. arenaria isolate W, which is virulent to heat-stable resistance genes in L. peruvianum PI 270435-2R2, PI 270435-3MH, and PI 126443-1MH. Clone LA 1708-I has a distinct heat-stable factor for resistance to Mi-avirulent M. arenaria isolate W, for which the gene symbol Mi-4 is proposed. A Mi-virulent M. arenaria isolate Le Grau du Roi was virulent on all Lycopersicon spp. accessions tested, including those with novel resistance genes.

  8. Effect of plant resistance and BioAct WG (Purpureocillium lilacinum strain 251) on Meloidogyne incognita in a tomato-cucumber rotation in a greenhouse.

    PubMed

    Giné, Ariadna; Sorribas, Francisco J

    2017-05-01

    The effectiveness of combining resistant tomato with BioAct WG (Purpureocillium lilacinum strain 251, Pl251) against Meloidogyne incognita was assessed in a tomato-cucumber rotation in a greenhouse over 2 years. Additionally, the enzymatic activity of the fungus, the percentage of fungal egg and juvenile parasitism, cardinal temperatures and the effect of water potential on mycelial growth and the soil receptivity to Pl251 were determined in vitro. Plant resistance was the only factor that suppressed nematode and crop yield losses. Percentage of egg parasitism in plots treated with BioAct WG was less than 2.6%. However, under in vitro conditions, Pl251 showed protease, lipase and chitinase activities and parasitised 94.5% of eggs, but no juveniles. Cardinal temperatures were 14.2, 24-26 and 35.4 °C. The maximum Pl251 mycelial growth was at -0.25 MPa and 25 °C. Soil temperatures and water potential in the greenhouse were in the range of the fungus. However, soil receptivity was lower in greenhouse soil, irrespective of sterilisation, than in sterilised sand. Plant resistance was the only factor able to suppress nematode densities, disease severity and yield losses, and to protect the following cucumber crop. Environmental factors involved in soil receptivity could have negatively affected fungus effectiveness. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  9. Microbial modulation of bacoside A biosynthetic pathway and systemic defense mechanism in Bacopa monnieri under Meloidogyne incognita stress.

    PubMed

    Gupta, Rupali; Singh, Akanksha; Srivastava, Madhumita; Singh, Vivek; Gupta, M M; Pandey, Rakesh

    2017-02-03

    Plant-associated beneficial microbes have been explored to fulfill the imperative function for plant health. However, their impact on the host secondary metabolite production and nematode disease management remains elusive. Our present work has shown that chitinolytic microbes viz., Chitiniphilus sp. MTN22 and Streptomyces sp. MTN14 singly as well as in combination modulated the biosynthetic pathway of bacoside A and systemic defense mechanism against Meloidogyne incognita in Bacopa monnieri. Interestingly, expression of bacoside biosynthetic pathway genes (3-Hydroxy-3-methylglutaryl coenzyme A reductase, mevalonate diphosphate decarboxylase, and squalene synthase) were upregulated in plants treated with the microbial combination in the presence as well as in absence of M. incognita stress. These microbes not only augmented bacoside A production (1.5 fold) but also strengthened host resistance via enhancement in chlorophyll a, defense enzymes and phenolic compounds like gallic acid, syringic acid, ferulic acid and cinnamic acid. Furthermore, elevated lignification and callose deposition in the microbial combination treated plants corroborate well with the above findings. Overall, the results provide novel insights into the underlying mechanisms of priming by beneficial microbes and underscore their capacity to trigger bacoside A production in B. monnieri under biotic stress.

  10. Nematicidal activity of the essential oil of Rhododendron anthopogonoides aerial parts and its constituent compounds against Meloidogyne incognita.

    PubMed

    Bai, Peng Hua; Bai, Chun Qi; Liu, Qi Zhi; Du, Shu Shan; Liu, Zhi Long

    2013-01-01

    Hydrodistilled essential oil from Rhododendron anthopogonoides Maxim. (Ericaceae) aerial parts was analysed by gas chromatography-mass spectrometry (GC-MS). A total of 42 compounds, accounting for 95.48% of the total oil, were identified. The main constituents of the essential oil were benzyl acetone (34.41%), nerolidol (10.19%), 1,4-cineole (8.41%), beta-caryophyllene (5.63%), gamma-elemene (5.10%), and spathulenol (3.06%). Four constituents were isolated from the essential oil based on fractionation. The essential oil of R. anthopogonoides possessed nematicidal activity against the root knot nematode (Meloidogyne incognita) with an LC50 value of 130.11 microg/ml. The main compound of the essential oil, benzyl acetone, exhibited nematicidal activity against M. incognita with an LC50 value of 74.17 microg/ml while 1,4-cineole, nerolidol, and beta-caryophyllene were not nematicidal at a concentration of 5 mg/ml. The essential oil of R. anthopogonoides and benzyl acetone show potential for their development as possible natural nematicides for the control of the root knot nematode.

  11. Influence of Meloidogyne incognita on the Content of Amino Acids and Nicotine in Tobacco Grown Under Gnotobiotic Conditions

    PubMed Central

    Hanounik, S. B.; Osborne, W. W.

    1975-01-01

    Seedlings of Meloidogyne incognita-resistant (N.C. 95) and -susceptible (McNair 30) tobacco cultivars were grown aseptically for 55 days inside isolator chambers in autoclaved soil infested with 0 or 3,000 axenized eggs of M. im ognita per 500 cc of soil. Healthy and infected plants were compared. Dry root weights of infected plants of resistant and susceptible cultivars were 16% and 84%, respectively, less than the controls. Sixteen amino acids, including those precursors for nicotine, and nicotine, increased significantly in infected roots of both cultivars. Increases in amino acids in infected roots ranged from 28% for valine to 103% for tyrosine in the resistant N.C. 95, and from 30% for leucine to 148% for tyrosine in lhe susceptible McNair 30. Nicotine content (dry weight basis) increased 42% and 62% in infected roots of resistant and susceptible cultivars, respectively. Nematode infection increased nicotine by 112% in leaves of N.C. 95, and decreased it by 56% in leaves of McNair 30. Root damage by M. incognita probably decreased nicotine movement into leaves of McNair 30. In N.C. 95, nicotine movement into leaves apparently was not adversel b affected due to lack of significant root damage. PMID:19308177

  12. Microbial modulation of bacoside A biosynthetic pathway and systemic defense mechanism in Bacopa monnieri under Meloidogyne incognita stress

    PubMed Central

    Gupta, Rupali; Singh, Akanksha; Srivastava, Madhumita; Singh, Vivek; Gupta, M. M.; Pandey, Rakesh

    2017-01-01

    Plant-associated beneficial microbes have been explored to fulfill the imperative function for plant health. However, their impact on the host secondary metabolite production and nematode disease management remains elusive. Our present work has shown that chitinolytic microbes viz., Chitiniphilus sp. MTN22 and Streptomyces sp. MTN14 singly as well as in combination modulated the biosynthetic pathway of bacoside A and systemic defense mechanism against Meloidogyne incognita in Bacopa monnieri. Interestingly, expression of bacoside biosynthetic pathway genes (3-Hydroxy-3-methylglutaryl coenzyme A reductase, mevalonate diphosphate decarboxylase, and squalene synthase) were upregulated in plants treated with the microbial combination in the presence as well as in absence of M. incognita stress. These microbes not only augmented bacoside A production (1.5 fold) but also strengthened host resistance via enhancement in chlorophyll a, defense enzymes and phenolic compounds like gallic acid, syringic acid, ferulic acid and cinnamic acid. Furthermore, elevated lignification and callose deposition in the microbial combination treated plants corroborate well with the above findings. Overall, the results provide novel insights into the underlying mechanisms of priming by beneficial microbes and underscore their capacity to trigger bacoside A production in B. monnieri under biotic stress. PMID:28157221

  13. Dose-response effects of clove oil from Syzygium aromaticum on the root-knot nematode Meloidogyne incognita.

    PubMed

    Meyer, Susan L F; Lakshman, Dilip K; Zasada, Inga A; Vinyard, Bryan T; Chitwood, David J

    2008-03-01

    Clove oil, derived from the plant Syzygium aromaticum (L.) Merr. & Perry, is active against various organisms, and was prepared in a soy lecithin/detergent formulation to determine concentrations active against the root-knot nematode Meloidogyne incognita (Kofoid and White) Chitwood. In microwell assays, the mean effective clove oil concentration that reduced egg hatch by 50% (EC(50)) was 0.097% (v/v) clove oil; the EC(50) for second-stage juvenile (J2) viability was 0.145% clove oil (compared with carrier control treatments). Volatiles from 5.0% clove oil reduced nematode egg hatch in water by 30%, and decreased viability of hatched J2 by as much as 100%. Reductions were not as large with nematodes in carrier. In soil trials with J2 recovered from Baermann funnels, the EC(50) = 0.192% clove oil (compared with water controls). The results demonstrated that the tested formulation is active against M. incognita eggs and J2, that the EC(50) values for J2 in the microwell studies and the soil recovery tests were similar to each other and that direct contact with the clove oil is needed for optimal management results with this natural product. (c) 2008 Society of Chemical Industry.

  14. Rotations with Coastal Bermudagrass and Fallow for Management of Meloidogyne incognita and Soilborne Fungi on Vegetable Crops

    PubMed Central

    Johnson, A. W.; Burton, G. W.; Wilson, J. P.; Golden, A. M.

    1995-01-01

    The efficacy of fallow and coastal bermudagrass (Cynodon dactylon) as a rotation crop for control of root-knot nematode (Meloidogyne incognita race 1) and soilborne fungi in okra (Hibiscus esculentus cv. Emerald), squash (Cucurbita pepo cv. Dixie Hybrid), and sweet corn (Zea mays cv. Merit) was evaluated in a 3-year field trial. Numbers of M. incognita in the soil and root-gall indices were greater on okra and squash than sweet corn and declined over the years on vegetable crops following fallow and coastal bermudagrass sod. Fusarium oxysporum and Pythium spp. were isolated most frequently from soil and dying okra plants. Numbers of colony-forming units of soilborne fungi generally declined as the number of years in sod increased, but were not affected by coastal bermudagrass sod. Yields of okra following 2-year and 3-year sod and squash following 2-year sod were greater than those following fallow. Yield of sweet corn was not different following fallow and coastal bermudagrass sod. PMID:19277312

  15. Nuclear receptor nhr-48 is required for pathogenicity of the second stage (J2) of the plant parasite Meloidogyne incognita

    PubMed Central

    Lu, Chao-Jun; Tian, Bao-Yu; Cao, Yi; Zou, Cheng-Gang; Zhang, Ke-Qin

    2016-01-01

    Nuclear receptors (NRs) are a diverse class of transcription factors, which are involved in regulating a large number of physiological events in metazoans. However, the function of NRs is poorly understood in plant-parasitic nematodes. Here, members of the NR1J+K group of NRs in nematodes, including the free-living and plant parasites, were examined and phylogenetically analyzed. We found that the number of members of the NR1J+K group in plant-parasitic nematodes was less than that in the free-living nematodes, suggesting this reduction of NR1J+K group members in plant parasites maybe arose during the separation of the free-living and intermediately plant parasitic nematodes (Bursaphelenchus xylophilus). Interestingly, the DNA-binding domain (DBD) and ligand-binding domain (LBD) of NR1J+K members were separated into two gene locations in the plant parasites. Knockdown of Meloidogyne incognita WBMinc13296, the ortholog of Caenorhabditis elegans nhr-48 DBD, reduced infectivity, delayed development, and decreased reproductivity. J2 of M. incognita subjected to silencing of WBMinc13295, the orthologs of B. xylophilus nhr-48 LBD, exhibited developmental lag within the host and reduced reproductivity. This study provides new insights into the function of NRs and suggests that NRs are potential targets for developing effective strategies for biological control of plant-parasitic nematodes. PMID:27762328

  16. Bioefficacy evaluation of controlled release formulations based on amphiphilic nano-polymer of carbofuran against Meloidogyne incognita infecting tomato.

    PubMed

    Pankaj; Shakil, Najam Akhtar; Kumar, Jitendra; Singh, M K; Singh, Khajan

    2012-01-01

    In the present investigation, the bioefficacy of developed carbofuran formulations, with PEG-600 (7a, CP1) & PEG-900 (7b, CP2) @ 5, 10 and 20 ppm, along with commercial formulation of carbofuran 3G (CP0) were evaluated against the root-knot nematode, Meloidogyne incognita infecting tomato (cv. Pusa Ruby) in pot and field conditions. The bioefficacy data indicated that the formulations developed by utilizing polymers having PEG - 900 (7b) as hydrophilic segment were effective even at 14 days post inoculation (dpi) as evident from shoot and root length. Also, the reduction in penetration was found to be maximum with CP2 (3.6 - 4.6 J2s) at all concentrations compared to CP1 (6.6-16.4 J2s) and CP0 (29.3-32.6 J2s). Overall, CP2 was more effective in reducing the number of nematodes up to 14 days, compared to CP1 and CP0. Both the CR formulations (CP1 and CP2) in general significantly reduced the number of galls, when compared to CP0. However, under field conditions, lower concentrations (5, and 10 ppm) of CP2, were less effective in controlling the gall formation whereas, CP2 at 20 ppm, was most effective than other treatments. The study revealed that the developed CR formulations of carbofuran have the potential for effective management of M. incognita in tomato under field conditions.

  17. Stage-Wise Identification and Analysis of miRNA from Root-Knot Nematode Meloidogyne incognita

    PubMed Central

    Subramanian, Parthiban; Choi, In-Chan; Mani, Vimalraj; Park, Junhyung; Subramaniyam, Sathiyamoorthy; Choi, Kang-Hyun; Sim, Joon-Soo; Lee, Chang-Muk; Koo, Ja Choon; Hahn, Bum-Soo

    2016-01-01

    In this study, we investigated global changes in miRNAs of Meloidogyne incognita throughout its life cycle. Small RNA sequencing resulted in approximately 62, 38, 38, 35, and 39 Mb reads in the egg, J2, J3, J4, and female stages, respectively. Overall, we identified 2724 known and 383 novel miRNAs (read count > 10) from all stages, of which 169 known and 13 novel miRNA were common to all the five stages. Among the stage-specific miRNAs, miR-286 was highly expressed in eggs, miR-2401 in J2, miR-8 and miR-187 in J3, miR-6736 in J4, and miR-17 in the female stages. These miRNAs are reported to be involved in embryo and neural development, muscular function, and control of apoptosis. Cluster analysis indicated the presence of 91 miRNA clusters, of which 36 clusters were novel and identified in this study. Comparison of miRNA families with other nematodes showed 17 families to be commonly absent in animal parasitic nematodes and M. incognita. Validation of 43 predicted common and stage-specific miRNA by quantitative PCR (qPCR) indicated their expression in the nematode. Stage-wise exploration of M. incognita miRNAs has not been carried out before and this work presents information on common and stage-specific miRNAs of the root-knot nematode. PMID:27775666

  18. Mi-flp-18 and Mi-mpk-1 Genes are Potential Targets for Meloidogyne incognita Control.

    PubMed

    Dong, Linlin; Xu, Jiang; Chen, Shilin; Li, Xiaolin; Zuo, Yuanmei

    2016-04-01

    Meloidogyne incognita is a major plant parasite that causes root-knot disease in numerous agricultural crops. This nematode has severely affected greenhouse crops in China. Chemical insecticides are generally used to control this pest, but they have adverse environmental and human toxicity effects; hence, safe and effective strategies for controlling the root-knot nematode (RKN) are necessary. FMRFamide-like peptides (FLPs) have diverse physiological and biological effects on the locomotory, feeding, and reproductive functions of nematodes, and mitogen-activated protein (MAP) kinase plays an important role in the regulation of transcription factors and protein kinases. These candidates are the common targets of RKN control. They are encoded by Mi-flp-18 and Mi-mpk-1 genes, respectively, in M. incognita . In this study, we used the RNA interference (RNAi) method to silence the transcription of these genes and determined the effects on the pathogenicity of RKN in potted plants. Real-time quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) revealed that Mi-mpk-1 gene expression could be reduced by 33% by RNAi. The RNAi-treated infective nematodes were inoculated with dsRNAs of Mi-flp-18 and Mi-mpk-1 in pot experiments. The root-knot numbers were reduced by 51% after Mi-flp-18 RNAi treatment. Further, the relative abundance of Mi-flp-18 was downregulated by 79% in the endoparasitic M. incognita . Mi-flp-18 RNAi treatment decreased egg masses by 92% and egg numbers by 58%. Mi-mpk-1 RNAi treatment reduced the root-knot numbers by 32% and, remarkably, lowered the relative abundance of Mi-mpk-1 in the endoparasitic M. incognita . Egg masses and numbers were reduced by 42 and 22%, respectively, after RKN was inoculated for 35 days with Mi-mpk-1 RNAi. Therefore, Mi-flp-18 and Mi-mpk-1 genes are susceptible to RNAi and can be used as potential targets for RKN control by regulating nematode infection, parasitism, and reproduction.

  19. Soil amendment with dried weed leaves as non-chemical approach for the management of Meloidogyne incognita infecting tomato.

    PubMed

    Radwan, M A; Abu-Elamayem, M M; Kassem, S M; El-Maadawy, E K

    2006-01-01

    In pot trial, dried ground weed leaves of Cynodon dactylon, Datura stramonium, Eichhomia crassipes, Emex spinosus, Ricinus communis and Sisymbrium irio were mixed with soil at the rate of 1, 3, 5 and 10 g/kg soil and compared their nematicidal potential with carbofuran as a standard against the root-knot nematode, M. incognita infecting tomato. In addition, their effects on growth rate of tomato plants were also investigated. The results showed that M. incognita populations in the soil and root galling were significantly suppressed when the dried leaves of the tested weeds at all rates were allowed to decompose in the soil. All amendments exhibited varying degree of reduction compared to control. The highest reduction was noticeable with the plants grown in Sisymbrium irio amended soil followed by Datura stramonium and Emex spinosus. In addition, employing high rate of the tested weeds gave higher activity in suppressing the nematode both in the soil and in tomato roots than using low rate. The data also indicated that all amendments at low rates significantly increased growth indices of tomato over control treatment, except Cynodon dactylon and Emex spinosus which decreased it, particularly in the shoot system. On the other hand, their high rates showed phytotoxic effects. These weed species may offer considerable promise as soil amendments for control of root-knot nematode, M. incognita.

  20. Influence of Infection of Cotton by Rotylenchulus Reniformis and Meloidogyne Incognita on the Production of Enzymes Involved in Systemic Acquired Resistance

    PubMed Central

    Aryal, Sudarshan K.; Davis, Richard F.; Stevenson, Katherine L.; Timper, Patricia; Ji, Pingsheng

    2011-01-01

    Systemic acquired resistance (SAR), which results in enhanced defense mechanisms in plants, can be elicited by virulent and avirulent strains of pathogens including nematodes. Recent studies of nematode reproduction strongly suggest that Meloidogyne incognita and Rotylenchulus reniformis induce SAR in cotton, but biochemical evidence of SAR was lacking. Our objective was to determine whether infection of cotton by M. incognita and R. reniformis increases the levels of P-peroxidase, G-peroxidase, and catalase enzymes which are involved in induced resistance. A series of greenhouse trials was conducted; each trial included six replications of four treatments applied to one of three cotton genotypes in a randomized complete block design. The four treatments were cotton plants inoculated with i) R. reniformis, ii) M. incognita, iii) BTH (Actigard), and iv) a nontreated control. Experiments were conducted on cotton genotypes DP 0935 B2RF (susceptible to both nematodes), LONREN-1 (resistant to R. reniformis), and M-120 RNR (resistant to M. incognita), and the level of P-peroxidase, G-peroxidase, and catalase activity was measured before and 2, 4, 6, 10, and 14 d after treatment application. In all cotton genotypes, activities of all three enzymes were higher (P ≤ 0.05) in leaves of plants infected with M. incognita and R. reniformis than in the leaves of control plants, except that M. incognita did not increase catalase activity on LONREN-1. Increased enzyme activity was usually apparent 6 d after treatment. This study documents that infection of cotton by M. incognita or R. reniformis increases the activity of the enzymes involved in systemic acquired resistance; thereby providing biochemical evidence to substantiate previous reports of nematode-induced SAR in cotton. PMID:23431029

  1. Influence of infection of cotton by rotylenchulus reniformis and meloidogyne incognita on the production of enzymes involved in systemic acquired resistance.

    PubMed

    Aryal, Sudarshan K; Davis, Richard F; Stevenson, Katherine L; Timper, Patricia; Ji, Pingsheng

    2011-09-01

    Systemic acquired resistance (SAR), which results in enhanced defense mechanisms in plants, can be elicited by virulent and avirulent strains of pathogens including nematodes. Recent studies of nematode reproduction strongly suggest that Meloidogyne incognita and Rotylenchulus reniformis induce SAR in cotton, but biochemical evidence of SAR was lacking. Our objective was to determine whether infection of cotton by M. incognita and R. reniformis increases the levels of P-peroxidase, G-peroxidase, and catalase enzymes which are involved in induced resistance. A series of greenhouse trials was conducted; each trial included six replications of four treatments applied to one of three cotton genotypes in a randomized complete block design. The four treatments were cotton plants inoculated with i) R. reniformis, ii) M. incognita, iii) BTH (Actigard), and iv) a nontreated control. Experiments were conducted on cotton genotypes DP 0935 B2RF (susceptible to both nematodes), LONREN-1 (resistant to R. reniformis), and M-120 RNR (resistant to M. incognita), and the level of P-peroxidase, G-peroxidase, and catalase activity was measured before and 2, 4, 6, 10, and 14 d after treatment application. In all cotton genotypes, activities of all three enzymes were higher (P ≤ 0.05) in leaves of plants infected with M. incognita and R. reniformis than in the leaves of control plants, except that M. incognita did not increase catalase activity on LONREN-1. Increased enzyme activity was usually apparent 6 d after treatment. This study documents that infection of cotton by M. incognita or R. reniformis increases the activity of the enzymes involved in systemic acquired resistance; thereby providing biochemical evidence to substantiate previous reports of nematode-induced SAR in cotton.

  2. Transcriptome analysis of resistant and susceptible alfalfa cultivars infected with root-knot nematode Meloidogyne incognita

    USDA-ARS?s Scientific Manuscript database

    Nematodes are one of the major limiting factors in alfalfa production. Root knot nematodes (RKN, Meloidogyne spp.) are widely distributed and economically important sedentary endoparasites of agricultural crops (Castagnone-Sereno et al. 2013) and they may inflict significant damage to alfalfa fields...

  3. Management of root-knot nematode (Meloidogyne incognita) in bottle gourd using different botanicals in pots.

    PubMed

    Singh, Tulika; Patel, B A

    2015-09-01

    A pot experiment was conducted to study the efficacy of different botanicals in varying doses for management of root-knot nematode, M. incognita in bottle gourd. The results exhibited that madar (Calotropis procera) and neem (Azadirachta indica) leaves application proved to be more effective in improving plant growth characters and reducing root-knot index and final nematode population. Among the doses tested, higher dose of 1.5 % (w/w) was more effective than lower ones.

  4. Exploitation of microbes for enhancing bacoside content and reduction of Meloidogyne incognita infestation in Bacopa monnieri L.

    PubMed

    Gupta, Rupali; Tiwari, Sudeep; Saikia, Shilpi K; Shukla, Virendra; Singh, Rashmi; Singh, S P; Kumar, P V Ajay; Pandey, Rakesh

    2015-01-01

    Despite the vast exploration of rhizospheric microbial wealth for crop yield enhancement, knowledge about the efficacy of microbial agents as biocontrol weapons against root-knot disease is scarce, especially in medicinal plants, viz., Bacopa monnieri. In the present investigation, rhizospheric microbes, viz., Bacillus megaterium, Glomus intraradices, Trichoderma harzianum ThU, and their combinations were evaluated for the management of Meloidogyne incognita (Kofoid and White) Chitwood and bacoside content enhancement in B. monnieri var CIM-Jagriti. A novel validated method Fourier transform near infrared was used for rapid estimation of total bacoside content. A significant reduction (2.75-fold) in root-knot indices was observed in the combined treatment of B. megaterium and T. harzianum ThU in comparison to untreated control plants. The same treatment also showed significant enhancement (1.40-fold) in total bacoside contents (plant active molecule) content using Fourier transform near-infrared (FT-NIR) method that analyses samples rapidly in an hour without solvent usage and provides ample scope for natural product studies.

  5. In-vitro Assays of Meloidogyne incognita and Heterodera glycines for Detection of Nematode-antagonistic Fungal Compounds

    PubMed Central

    Nitao, James K.; Meyer, Susan L. F.; Chitwood, David J.

    1999-01-01

    In-vitro methods were developed to test fungi for production of metabolites affecting nematode egg hatch and mobility of second-stage juveniles. Separate assays were developed for two nematodes: root-knot nematode (Meloidogyne incognita) and soybean cyst nematode (Heterodera glycines). For egg hatch to be successfully assayed, eggs must first be surface-disinfested to avoid the confounding effects of incidental microbial growth facilitated by the fungal culture medium. Sodium hypochlorite was more effective than chlorhexidine diacetate or formaldehyde solutions at surface-disinfesting soybean cyst nematode eggs from greenhouse cultures. Subsequent rinsing with sodium thiosulfate to remove residual chlorine from disinfested eggs did not improve either soybean cyst nematode hatch or juvenile mobility. Soybean cyst nematode hatch in all culture media was lower than in water. Sodium hypochlorite was also used to surface-disinfest root-knot nematode eggs. In contrast to soybean cyst nematode hatch, root-knot nematode hatch was higher in potato dextrose broth medium than in water. Broth of the fungus Fusarium equiseti inhibited root-knot nematode egg hatch and was investigated in more detail. Broth extract and its chemical fractions not only inhibited egg hatch but also immobilized second-stage juveniles that did hatch, confirming that the fungus secretes nematode-antagonistic metabolites. PMID:19270887

  6. Effects of Site-specific Application of Aldicarb on Cotton in a Meloidogyne incognita-infested Field

    PubMed Central

    Wrather, J. A.; Stevens, W. E.; Kirkpatrick, T. L.; Kitchen, N. R.

    2002-01-01

    Cotton farmers in Missouri commonly apply a single rate of aldicarb throughout the field at planting to protect their crop from Meloidogyne incognita, even though these nematodes are spatially aggregated. Our purpose was to determine the effect of site-specific application of aldicarb on cotton production in a field infested with these nematodes in 1997 and 1998. Cotton yields were collected from sites not treated with aldicarb (control), sites receiving aldicarb at the standard recommended rate of 0.58 kg a.i./ha, and sites receiving specific aldicarb rates based on the soil population densities of second-stage infective juveniles of root-knot nematode. Yields for the standard rate and site-specific rate treatments were similar and greater (P ≤ 0.05) than the control treatment. Less aldicarb was used for the site-specific than the uniform-rate treatment each year—46% less in 1997 and 61% less in 1998. Costs associated with the site-specific treatment were very high compared with the uniform-rate treatment due to a greater number of soil samples analyzed for nematodes. Site-specific application of aldicarb for root-knot nematode management in cotton may pose fewer environmental risks than the uniform-rate application of aldicarb. PMID:19265917

  7. Transcriptome analysis of resistant and susceptible tobacco (Nicotiana tabacum) in response to root-knot nematode Meloidogyne incognita infection.

    PubMed

    Xing, Xuexia; Li, Xiaohui; Zhang, Mingzhen; Wang, Yuan; Liu, Bingyang; Xi, Qiliang; Zhao, Ke; Wu, Yunjie; Yang, Tiezhao

    2017-01-22

    The root-knot nematode (RKN) Meloidogyne incognita reproduces on the roots of tobacco (Nicotiana tabacum), damaging crops, reducing crop yield, and causing economic losses annually. The development of resistant genotypes is an alternative strategy to effectively control these losses. However, the molecular mechanism responsible for host pathogenesis and defense responses in tobacco specifically against RKNs remain poorly understood. Here, root transcriptome analysis of resistant (Yuyan12) and susceptible (Changbohuang) tobacco varieties infected with RKNs was performed. Moreover, 2623 and 545 differentially expressed genes (DEGs) in RKN-infected roots were observed in Yuyan12 and Changbohuang, respectively, compared to those in non-infected roots, including 289 DEGs commonly expressed in the two genotypes. Among these DEGs, genes encoding cell wall modifying proteins, auxin-related proteins, the ROS scavenging system, and transcription factors involved in various biological and physiochemical processes were significantly expressed in both the resistant and susceptible genotypes. This work is thus the first report on the relationships in the RKN-tobacco interaction using transcriptome analysis, and the results provide important information on the mechanism of RKN resistance in tobacco. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Evaluation of entomopathogenic nematodes and the supernatants of the in vitro culture medium of their mutualistic bacteria for the control of the root-knot nematodes Meloidogyne incognita and M. arenaria.

    PubMed

    Kepenekci, Ilker; Hazir, Selcuk; Lewis, Edwin E

    2016-02-01

    The suppressive effects of various formulations of four entomopathogenic nematode (EPN) species and the supernatants of their mutualistic bacteria on the root-knot nematodes (RKNs) Meloidogyne incognita and M. arenaria in tomato roots were evaluated. The EPNs Steinernema carpocapsae, S. feltiae, S. glaseri and Heterorhabditis bacteriophora were applied as either live infective juveniles (IJs) or infected insect cadavers. Spent medium from culturing the bacterial symbionts Xenorhabdus bovienii and Photorhabdus luminescens kayaii with the cells removed was also applied without their nematode partners. The aqueous suspensions of IJs, infected cadaver applications of EPNs and especially treatments of X. bovienii supernatant suppressed the negative impact of RKNs on tomatoes. Specific responses to treatment were reduced RKN egg masses, increased plant height and increased fresh and dry weights compared with the control where only RKNs were applied. Among the treatments tested, the plant-dipping method of X. bovienii into bacterial culture fluid may be the most practical and effective method for M. incognita and M. arenaria control. © 2015 Society of Chemical Industry.

  9. Differential expression of antioxidant enzymes and PR-proteins in compatible and incompatible interactions of cowpea (Vigna unguiculata) and the root-knot nematode Meloidogyne incognita.

    PubMed

    Oliveira, J T A; Andrade, N C; Martins-Miranda, A S; Soares, A A; Gondim, D M F; Araújo-Filho, J H; Freire-Filho, F R; Vasconcelos, I M

    2012-02-01

    This study aimed to evaluated the resistance and susceptibility of 10 cowpea cultivars to Meloidogyne incognita in field studies and to analyze the kinetics of the enzymes superoxide dismutase, catalase, peroxidase, chitinase, β-1,3-glucanases and cystein proteinase inhibitors in the root system of two contrasting cowpea cultivars after inoculation with M. incognita. The cultivars CE-31 and Frade Preto were highly resistant; CE-28, CE-01, CE-315, CE-237, were very resistant; CE-70 and CE-216 were moderately resistant, whereas Vita-3 and CE-109 were slightly resistant. In the roots of the highly resistant cultivar CE-31 the activity of the antioxidant enzyme superoxide dismutase increased and catalase decreased and those of the pathogenesis-related proteins chitinase, β-1,3-glucanase, peroxidase and cystein proteinase inhibitor increased in comparison with the root system of the slightly resistant CE-109, during the course of M. incognita infestation. Thus the changes in the activities of these enzymes might be related to the smaller final population of M. incognita in CE-31 and may contribute to the high resistance of this cowpea cultivar against infection and colonization by this nematode species.

  10. Evaluation of a nematode bio-product Dbx-20% against root-knot nematode Meloidogyne incognita affecting grapevine under field conditions.

    PubMed

    Aboul-Eid, H Z; Noweer, E M A; Ashour, N E; Ameen, Hoda H

    2006-01-01

    A field trial was conducted in El-Shourouk Farm, El-Beheira governorate, western Nile valley, Egypt to determine the effectiveness of the commercial bio-product Dbx 1003 20% containing the nematode-trapping fungus Dactylaria brochopaga against root-knot nematode Meloidogyne incognita infesting grapevine variety Superior. Its effects on plant growth criteria and yield production were also investigated. The fungus was introduced to soil by either of two ways. First: soil was drenched with spore suspension at the rate of 3 l/tree. Second: 1/2 kg of a vermiculite substrate, as a carrier of spores and mycelia was added around each tree both as single and twice application in autumn and spring. All treatments significantly reduced M. incognita J2 in soil and number of root galls compared with the untreated control. Significant yield increases have been observed with all treatments compared with the untreated control. Spores suspension twice applications gave the highest yield production.

  11. Virtual screening and in vitro assay of potential drug like inhibitors from spices against Glutathione-S-Transferase of Meloidogyne incognita

    PubMed Central

    Babu, Rosana O; Moorkoth, Dinsha; Azeez, Shamina; Eapen, Santhosh J

    2012-01-01

    Glutathione S-transferases (GSTs) enzymes are critical antioxidant and detoxification system responsible for long-term existence of nematodes in host species. Hence, 16 phytochemicals predicted and reported to have potential nematicidal activity have been docked to GST enzyme of Meloidogyne incognita to assess their binding affinity and inhibitory activity. In vitro effects of these phytochemicals from in silico results have been done for validation of docking studies and efficacy in GST inhibition of following compounds such as alpha- pinene, alpha- terpineol, beta- caryophyllene, capsaicin, cinnamic acid, citronellol, curcumin, eugenol, geraniol, isoeugenol, linalool, myristicin, neral, NVA (N-vanillylnonanamide), piperine, vanillin have been revealed. Nematode inhibition in vitro bioassay for selected compounds could conclude that maximum mortality was observed with highest concentrations of beta- caryophyllene (78%) followed by eugenol (61.6%), cinnamic acid (55%) and N-vanillylnonanamide (49%). These findings thus suggest that the above phytochemicals could be potentially developed as nematicidal molecules against M. incognita infections. PMID:22553389

  12. Integrated application of some compatible biocontrol agents along with mustard oil seed cake and furadan on Meloidogyne incognita infecting tomato plants.

    PubMed

    Goswami, Bijoy Kumar; Pandey, Rajesh Kumar; Rathour, Kabindra Singh; Bhattacharya, Chaitali; Singh, Lokendra

    2006-11-01

    Experiments were carried out to study the effect of two fungal bioagents along with mustard oil cake and furadan against root knot nematode Meloidogyne incognita infecting tomato under greenhouse condition. Bioagents viz., Paecilomyces lilacinus and Trichoderma viride alone or in combination with mustard cake and furadan promoted plant growth, reduced number of galls/plant, egg masses/root system and eggs/egg mass. The fungal bioagents along with mustard cake and nematicide showed least nematodes reproduction factor as compared to untreated infested soil.

  13. Nematicidal Activity of Kojic Acid Produced by Aspergillus oryzae against Meloidogyne incognita.

    PubMed

    Kim, Tae Yoon; Jang, Ja Yeong; Jeon, Sun Jeong; Lee, Hye Won; Bae, Chang-Hwan; Yeo, Joo Hong; Lee, Hyang Burm; Kim, In Seon; Park, Hae Woong; Kim, Jin-Cheol

    2016-08-28

    The fungal strain EML-DML3PNa1 isolated from leaf of white dogwood (Cornus alba L.) showed strong nematicidal activity with juvenile mortality of 87.6% at a concentration of 20% fermentation broth filtrate at 3 days after treatment. The active fungal strain was identified as Aspergillus oryzae, which belongs to section Flavi, based on the morphological characteristics and sequence analysis of the ITS rDNA, calmodulin (CaM), and β-tubulin (BenA) genes. The strain reduced the pH value to 5.62 after 7 days of incubation. Organic acid analysis revealed the presence of citric acid (515.0 mg/kg), malic acid (506.6 mg/kg), and fumaric acid (21.7 mg/kg). The three organic acids showed moderate nematicidal activities, but the mixture of citric acid, malic acid, and fumaric acid did not exhibit the full nematicidal activity of the culture filtrate of EML- DML3PNa1. Bioassay-guided fractionation coupled with (1)H- and (13)C-NMR and EI-MS analyses led to identification of kojic acid as the major nematicidal metabolite. Kojic acid exhibited dose-dependent mortality and inhibited the hatchability of M. incognita, showing EC50 values of 195.2 µg/ml and 238.3 µg/ml, respectively, at 72 h postexposure. These results suggest that A. oryzae EML-DML3PNa1 and kojic acid have potential as a biological control agent against M. incognita.

  14. Relationships between initial population densities of Meloidogyne incognita race 2 and nematode population development in terms of variable soybean resistance

    PubMed Central

    Mc Donald, Alexander H.; De Waele, Dirk

    2010-01-01

    The effect of increasing initial population density levels (Pi) of Meloidogyne incognita race 2 on nematode population development and yield of a susceptible (Prima2000) and resistant (LS5995) soybean cultivar was investigated. Two experiments, one in a hail net cage and one in microplots, were conducted one each during two consecutive growing seasons at Potchefstroom in the North West Province of South Africa. Nematode reproduction was assessed by determining the number of eggs and second-stage juveniles (J2) in the rhizosphere and roots, egg masses, egg-laying females (ELF) and reproduction factor (Rf) values per root system at harvesting 110 days after planting. Percentage yield reduction in the two cultivars was also calculated. Strong non-linear relationships existed between all nematode variables as well as between Pi and percentage yield loss in both cultivars for both experiments in this study. Significantly higher numbers of eggs and J2, egg masses and ELF were maintained in the roots of the nematode-susceptible Prima2000 than in the resistant LS5995 from Pi = 100 and higher in both experiments. Rf values were inversely related to Pi for both cultivars and were lowest on LS5995, with Prima2000 maintaining significantly higher Rf values in both experiments. Yield loss in LS5995 was at least six times higher than that of Prima2000. The difference in monetary terms is demonstrated, although it is suggested that host plant resistance to plant-parasitic nematodes may not be sufficient as the only management tool in highly infested soils or in rotation systems including nematode susceptible crops. PMID:22736837

  15. Relationships between initial population densities of Meloidogyne incognita race 2 and nematode population development in terms of variable soybean resistance.

    PubMed

    Fourie, Hendrika; Mc Donald, Alexander H; De Waele, Dirk

    2010-03-01

    The effect of increasing initial population density levels (Pi) of Meloidogyne incognita race 2 on nematode population development and yield of a susceptible (Prima2000) and resistant (LS5995) soybean cultivar was investigated. Two experiments, one in a hail net cage and one in microplots, were conducted one each during two consecutive growing seasons at Potchefstroom in the North West Province of South Africa. Nematode reproduction was assessed by determining the number of eggs and second-stage juveniles (J2) in the rhizosphere and roots, egg masses, egg-laying females (ELF) and reproduction factor (Rf) values per root system at harvesting 110 days after planting. Percentage yield reduction in the two cultivars was also calculated. Strong non-linear relationships existed between all nematode variables as well as between Pi and percentage yield loss in both cultivars for both experiments in this study. Significantly higher numbers of eggs and J2, egg masses and ELF were maintained in the roots of the nematode-susceptible Prima2000 than in the resistant LS5995 from Pi = 100 and higher in both experiments. Rf values were inversely related to Pi for both cultivars and were lowest on LS5995, with Prima2000 maintaining significantly higher Rf values in both experiments. Yield loss in LS5995 was at least six times higher than that of Prima2000. The difference in monetary terms is demonstrated, although it is suggested that host plant resistance to plant-parasitic nematodes may not be sufficient as the only management tool in highly infested soils or in rotation systems including nematode susceptible crops.

  16. Effect of Three Plant Residues and Chicken Manure used as Biofumigants at Three Temperatures on Meloidogyne incognita Infestation of Tomato in Greenhouse Experiments

    PubMed Central

    López-Pérez, Jose-Antonio; Roubtsova, Tatiana; Ploeg, Antoon

    2005-01-01

    Plant residues of broccoli, melon, and tomato with or without addition of chicken manure were used as biofumigants in two pot experiments with Meloidogyne incognita-infested soils. The efficacy of these biofumigants in controlling M. incognita infestation in susceptible tomato bio-assay plants was studied at soil temperatures of 20º, 25º, and 30 ºC. None of the plant residues was effective at 20 ºC, and broccoli was more effective than tomato or melon at 25 ºC. At 30 ºC all three plant residues reduced M. incognita infestation of tomato to very low levels. Chicken manure was effective in one of two experiments at 20 ºC, and at 25 ºC enhanced the efficacy of tomato and melon residue in one of two experiments. At 30 ºC chicken manure was equally effective as the three plant residues but did not further decrease infestation levels in plant residue amended soils. It is concluded that biofumigation to control M. incognita is unlikely to be effective under cool conditions, that at soil temperatures around 25 ºC broccoli is more effective than melon and tomato, and that the addition of chicken manure at this soil temperature may enhance the efficacy. At high soil temperatures, of approximately 30 ºC, the biofumigant source seems of minor importance as strong reductions in tomato infestation by M. incognita were achieved by addition of each of the three plant residues as well as by addition of chicken manure. PMID:19262896

  17. In vitro comparison of protease activities in preparations from free-living (Panagrellus redivivus) and plant-parasitic (Meloidogyne incognita) nematodes using FMRFa and FMRFa-like peptides as substrates

    USDA-ARS?s Scientific Manuscript database

    Extracts prepared from the free-living nematode Panagrellus redivivus and the plant-parasitic nematode Meloidogyne incognita were each capable of degrading a broad range of nematode FMRFamide-like peptides (FLPs), key regulatory messengers of nematode growth and development. Clear quantitative diffe...

  18. Mutations in Acetylcholinesterase2 (ace2) increase the insensitivity of acetylcholinesterase to fosthiazate in the root-knot nematode Meloidogyne incognita.

    PubMed

    Huang, Wen-Kun; Wu, Qin-Song; Peng, Huan; Kong, Ling-An; Liu, Shi-Ming; Yin, Hua-Qun; Cui, Ru-Qiang; Zhan, Li-Ping; Cui, Jiang-Kuan; Peng, De-Liang

    2016-11-29

    The root-knot nematode Meloidogyne incognita causes severe damage to continuously cropping vegetables. The control of this nematode relies heavily on organophosphate nematicides in China. Here, we described resistance to the organophosphate nematicide fosthiazate in a greenhouse-collected resistant population (RP) and a laboratory susceptible population (SP) of M. incognita. Fosthiazate was 2.74-fold less toxic to nematodes from RP than that from SP. Quantitative real-time PCR revealed that the acetylcholinesterase2 (ace2) transcription level in the RP was significantly higher than that in the SP. Eighteen nonsynonymous amino acid differences in ace2 were observed between the cDNA fragments of the RP and SP. The acetylcholinesterase (AChE) protein activity in the RP was significantly reduced compared with that in the SP. After knocking down the ace2 gene, the ace2 transcription level was significantly decreased, but no negative impact on the infection of juveniles was observed. The 50% lethal concentration of the RNAi RP population decreased 40%, but the inhibition rate of fosthiazate against AChE activity was significantly increased in RP population. Thus, the increased fosthiazate insensitivity in the M. incognita resistant population was strongly associated with mutations in ace2. These results provide valuable insights into the resistance mechanism of root-knot nematode to organophosphate nematicides.

  19. Mutations in Acetylcholinesterase2 (ace2) increase the insensitivity of acetylcholinesterase to fosthiazate in the root-knot nematode Meloidogyne incognita

    PubMed Central

    Huang, Wen-Kun; Wu, Qin-Song; Peng, Huan; Kong, Ling-An; Liu, Shi-Ming; Yin, Hua-Qun; Cui, Ru-Qiang; Zhan, Li-Ping; Cui, Jiang-Kuan; Peng, De-Liang

    2016-01-01

    The root-knot nematode Meloidogyne incognita causes severe damage to continuously cropping vegetables. The control of this nematode relies heavily on organophosphate nematicides in China. Here, we described resistance to the organophosphate nematicide fosthiazate in a greenhouse-collected resistant population (RP) and a laboratory susceptible population (SP) of M. incognita. Fosthiazate was 2.74-fold less toxic to nematodes from RP than that from SP. Quantitative real-time PCR revealed that the acetylcholinesterase2 (ace2) transcription level in the RP was significantly higher than that in the SP. Eighteen nonsynonymous amino acid differences in ace2 were observed between the cDNA fragments of the RP and SP. The acetylcholinesterase (AChE) protein activity in the RP was significantly reduced compared with that in the SP. After knocking down the ace2 gene, the ace2 transcription level was significantly decreased, but no negative impact on the infection of juveniles was observed. The 50% lethal concentration of the RNAi RP population decreased 40%, but the inhibition rate of fosthiazate against AChE activity was significantly increased in RP population. Thus, the increased fosthiazate insensitivity in the M. incognita resistant population was strongly associated with mutations in ace2. These results provide valuable insights into the resistance mechanism of root-knot nematode to organophosphate nematicides. PMID:27897265

  20. Tolerance to Rotylenchulus reniformis and Resistance to Meloidogyne incognita Race 3 in High-Yielding Breeding Lines of Upland Cotton

    PubMed Central

    Cook, C. G.; Robinson, A. F.; Namken, L. N.

    1997-01-01

    Field experiments in 1992 and 1994 were conducted to determine the effect of Rotylenchulus reniformis, reniform nematode, on lint yield and fiber quality of 10 experimental breeding lines of cotton (Gossypium hirsutum) in untreated plots or plots fumigated with 1,3-dichloropropene. Controls were La. RN 1032, a germplasm line possessing some resistance to R. reniformis, and Stoneville 453, a cultivar that is susceptible to reniform nematode. Several breeding lines produced greater lint yields than Stoneville 453 or La. RN 1032 in both fumigated and untreated plots. Average lint yield suppression due to R. reniformis for six of the 10 breeding lines was less than half of the 52% yield reduction sustained by Stoneville 453. In growth chamber experiments, R. reniformis multiplication factors for La. RN 1032 and breeding lines N222-1-91, N320-2-91, and N419-1-91 were significantly lower than on Deltapine 16 and Stoneville 453 at 6 weeks after inoculation. R. reniformis populations increased by more than 50-fold on all entries within 10 weeks. In growth chambers, the breeding lines N220-1-92, N222-1-91, and N320-2-91 were resistant to Meloidoglyne incognita race 3; multiplication factors were ≤1.0 at both 6 weeks and 10 weeks after inoculation compared with 25.8 and 26.5 for Deltapine 16 at 6 and 10 weeks after inoculation, respectively, and 9.1 and 2.6 for Stoneville 453. Thus, the results indicate that significant advances have been made in developing improved cotton germplasm lines with the potential to produce higher yields in soils infested with R. reniformis or M. incogaita. In addition to good yield potential, germplasm lines N222-1-91 and N320-2-91 appear to possess low levels of resistance to R. reniformis and a high level of resistance to M. incognita. This germplasm combines high yield potential with significant levels of resistance to both R. reniformis and M. incognita. PMID:19274165

  1. Genome-wide analysis of Excretory/Secretory proteins in root-knot nematode, Meloidogyne incognita provides potential targets for parasite control.

    PubMed

    Gahoi, Shachi; Gautam, Budhayash

    2017-04-01

    The root-knot nematode, Meloidogyne incognita causes significant damage to various economically important crops. Infection is associated with secretion of effector proteins into host cytoplasm and interference with host innate immunity. To combat this infection, the identification and functional annotations of Excretory/Secretory (ES) proteins serve as a key to produce durable control measures. The identification of ES proteins through experimental methods are expensive and time consuming while bioinformatics approaches are cost-effective by prioritizing the experimental analysis of potential drug targets for parasitic diseases. In this study, we predicted and functionally annotated the 1889 ES proteins in M. incognita genome using integration of several bioinformatics tools. Of these 1889 ES proteins, 473 (25%) had orthologues in free living nematode Caenorhabditis elegans, 825(67.8%) in parasitic nematodes whereas 561 (29.7%) appeared to be novel and M. incognita specific molecules. Of the C. elegans homologues, 17 ES proteins had "loss of function phenotype" by RNA interference and could represent potential drug targets for parasite intervention and control. We could functionally annotate 429 (22.7%) ES proteins using Gene Ontology (GO) terms, 672 (35.5%) proteins to protein domains and established pathway associations for 223 (11.8%) sequences using Kyoto Encyclopaedia of Genes and Genomes (KEGG). The 162 (8.5%) ES proteins were also mapped to several important plant cell-wall degrading CAZyme families including chitinase, cellulase, xylanase, pectate lyase and endo-β-1,4-xylanase. Our comprehensive analysis of M. incognita secretome provides functional information for further experimental study.

  2. Optimization of In Vitro Techniques for Distinguishing between Live and Dead Second Stage Juveniles of Heterodera glycines and Meloidogyne incognita

    PubMed Central

    2016-01-01

    Heterodera glycines (Soybean Cyst nematode, or SCN) and Meloidogyne incognita (Root-Knot nematode, or RKN) are two damaging plant-parasitic nematodes on important field crops. Developing a quick method to distinguish between live and dead SCN and RKN second stage juveniles (J2) is vital for high throughput screening of pesticides or biological compounds against SCN and RKN. The in vitro assays were conducted in 96-well plates to determine the optimum chemical stimulus to distinguish between live and dead SCN and RKN J2. Sodium carbonate (Na2CO3), sodium bicarbonate (NaHCO3), and sodium hydroxide (NaOH) were evaluated for the nematode response to see if these compounds can help distinguish between viable from the dead J2. Results indicated that live SCN J2 responded equally (P ≤ 0.05) to 1 μl Na2CO3 and 10 μl NaHCO3 in 100 μl of water at pH = 10. Live SCN J2 responded by twisting their bodies in a curling shape and increasing rate of movements within 2 minutes of exposure. The twisting activity continued for up to 30 minutes. Live RKN J2 responded by increasing activity with the application of 1 μl NaOH in 100 μl of water at pH = 10 also in the 2 minutes to 30 minutes time frame. Furthermore, in growth chamber tests to confirm the infectivity of live SCN. The live SCN as determined by exposure to 1 μl of Na2CO3 indicated 60.5% of the SCN J2 were alive and of those, 29.5% were infective and entered the soybean roots. The 1 μl of NaOH stimulus revealed that 75.2% RKN J2 were alive and of those, 14.9% were infective and entered soybean roots. These results confirmed that 1 μl of Na2CO3 added to 100 μl suspension of SCN J2 and 1 μl of NaOH added to 100 μl suspension of RKN J2 are the effective stimuli for rapidly distinguishing between live and dead SCN and RKN J2 in vitro. SCN and RKN J2 responded differently to different compounds. PMID:27144277

  3. Optimization of In Vitro Techniques for Distinguishing between Live and Dead Second Stage Juveniles of Heterodera glycines and Meloidogyne incognita.

    PubMed

    Xiang, Ni; Lawrence, Kathy S

    2016-01-01

    Heterodera glycines (Soybean Cyst nematode, or SCN) and Meloidogyne incognita (Root-Knot nematode, or RKN) are two damaging plant-parasitic nematodes on important field crops. Developing a quick method to distinguish between live and dead SCN and RKN second stage juveniles (J2) is vital for high throughput screening of pesticides or biological compounds against SCN and RKN. The in vitro assays were conducted in 96-well plates to determine the optimum chemical stimulus to distinguish between live and dead SCN and RKN J2. Sodium carbonate (Na2CO3), sodium bicarbonate (NaHCO3), and sodium hydroxide (NaOH) were evaluated for the nematode response to see if these compounds can help distinguish between viable from the dead J2. Results indicated that live SCN J2 responded equally (P ≤ 0.05) to 1 μl Na2CO3 and 10 μl NaHCO3 in 100 μl of water at pH = 10. Live SCN J2 responded by twisting their bodies in a curling shape and increasing rate of movements within 2 minutes of exposure. The twisting activity continued for up to 30 minutes. Live RKN J2 responded by increasing activity with the application of 1 μl NaOH in 100 μl of water at pH = 10 also in the 2 minutes to 30 minutes time frame. Furthermore, in growth chamber tests to confirm the infectivity of live SCN. The live SCN as determined by exposure to 1 μl of Na2CO3 indicated 60.5% of the SCN J2 were alive and of those, 29.5% were infective and entered the soybean roots. The 1 μl of NaOH stimulus revealed that 75.2% RKN J2 were alive and of those, 14.9% were infective and entered soybean roots. These results confirmed that 1 μl of Na2CO3 added to 100 μl suspension of SCN J2 and 1 μl of NaOH added to 100 μl suspension of RKN J2 are the effective stimuli for rapidly distinguishing between live and dead SCN and RKN J2 in vitro. SCN and RKN J2 responded differently to different compounds.

  4. Genome-wide survey and analysis of microsatellites in nematodes, with a focus on the plant-parasitic species Meloidogyne incognita

    PubMed Central

    2010-01-01

    Background Microsatellites are the most popular source of molecular markers for studying population genetic variation in eukaryotes. However, few data are currently available about their genomic distribution and abundance across the phylum Nematoda. The recent completion of the genomes of several nematode species, including Meloidogyne incognita, a major agricultural pest worldwide, now opens the way for a comparative survey and analysis of microsatellites in these organisms. Results Using MsatFinder, the total numbers of 1-6 bp perfect microsatellites detected in the complete genomes of five nematode species (Brugia malayi, Caenorhabditis elegans, M. hapla, M. incognita, Pristionchus pacificus) ranged from 2,842 to 61,547, and covered from 0.09 to 1.20% of the nematode genomes. Under our search criteria, the most common repeat motifs for each length class varied according to the different nematode species considered, with no obvious relation to the AT-richness of their genomes. Overall, (AT)n, (AG)n and (CT)n were the three most frequent dinucleotide microsatellite motifs found in the five genomes considered. Except for two motifs in P. pacificus, all the most frequent trinucleotide motifs were AT-rich, with (AAT)n and (ATT)n being the only common to the five nematode species. A particular attention was paid to the microsatellite content of the plant-parasitic species M. incognita. In this species, a repertoire of 4,880 microsatellite loci was identified, from which 2,183 appeared suitable to design markers for population genetic studies. Interestingly, 1,094 microsatellites were identified in 801 predicted protein-coding regions, 99% of them being trinucleotides. When compared against the InterPro domain database, 497 of these CDS were successfully annotated, and further assigned to Gene Ontology terms. Conclusions Contrasted patterns of microsatellite abundance and diversity were characterized in five nematode genomes, even in the case of two closely related

  5. Increased size of cotton root system does not impart tolerance to Meloidogyne incognita

    USDA-ARS?s Scientific Manuscript database

    Plant tolerance or intolerance to parasitic nematodes represent a spectrum describing the degree of damage inflicted by the nematode on the host plant. Tolerance is typically measured in terms of yield suppression. Instances of plant tolerance to nematodes have been documented in some crops, inclu...

  6. Coupling of MIC-3 overexpression with the chromosomes 11 and 14 root-knot nematode (RKN) (Meloidogyne incognita) resistance QTLs provides insights into the regulation of the RKN resistance response in Upland cotton (Gossypium hirsutum).

    PubMed

    Wubben, Martin J; Callahan, Franklin E; Jenkins, Johnie N; Deng, Dewayne D

    2016-09-01

    Genetic analysis of MIC-3 transgene with RKN resistance QTLs provides insight into the resistance regulatory mechanism and provides a framework for testing additional hypotheses. Resistance to root-knot nematode (RKN) (Meloidogyne incognita) in Upland cotton (Gossypium hirsutum) is mediated by two major quantitative trait loci (QTL) located on chromosomes 11 and 14. The MIC-3 (Meloidogyne Induced Cotton3) protein accumulates specifically within the immature galls of RKN-resistant plants that possess these QTLs. Recently, we showed that MIC-3 overexpression in an RKN-susceptible cotton genotype suppressed RKN egg production but not RKN-induced root galling. In this study, the MIC-3 overexpression construct T-DNA in the single-copy transgenic line '14-7-1' was converted into a codominant molecular marker that allowed the marker assisted selection of F2:3 cotton lines, derived from a cross between 14-7-1 and M-240 RNR, having all possible combinations of the chromosomes 11 and 14 QTLs with and without the MIC-3 overexpression construct. Root-knot nematode reproduction (eggs g(-1) root) and severity of RKN-induced root galling were assessed in these lines. We discovered that the addition of MIC-3 overexpression suppressed RKN reproduction in lines lacking both resistance QTLs and in lines having only the chromosome 14 QTL, suggesting an additive effect of the MIC-3 construct with this QTL. In contrast, MIC-3 overexpression did not improve resistance in lines having the single chromosome 11 QTL or in lines having both resistance QTLs, suggesting an epistatic interaction between the chromosome 11 QTL and the MIC-3 construct. Overexpression of MIC-3 did not affect the severity of RKN-induced root galling regardless of QTL genotype. These data provide new insights into the relative order of action of the chromosomes 11 and 14 QTLs and their potential roles in regulating MIC-3 expression as part of the RKN resistance response.

  7. Persistence and Suppressiveness of Pasteuria penetrans to Meloidogyne arenaria Race.

    PubMed

    Cetintas, R; Dickson, D W

    2004-12-01

    The long-term persistence and suppressiveness of Pasteuria penetrans against Meloidogyne arenaria race 1 were investigated in a formerly root-knot nematode suppressive site following 9 years of continuous cultivation of three treatments and 4 years of continuous peanut. The three treatments were two M. arenaria race 1 nonhost crops, bahiagrass (Paspalum notatum cv. Pensacola var. Tifton 9), rhizomal peanut (Arachis glabrata cv. Florigraze), and weed fallow. Two root-knot nematode susceptible weeds commonly observed in weed fallow plots were hairy indigo (Indigofera hirsuta) and alyce clover (Alysicarpus vaginalis). The percentage of J2 with endospores attached reached the highest level of 87% in 2000 in weed fallow, and 63% and 53% in 2002 in bahiagrass and rhizomal peanut, respectively. The percentage of endospore-filled females extracted from peanut roots grown in weed fallow plots increased from nondetectable in 1999 to 56% in 2002, whereas the percentages in bahiagrass and rhizomal peanut plots were 41% and 16%, respectively. Over 4 years, however, there was no strong evidence that endospores densities reached suppressive levels because peanut roots, pods, and pegs were heavily galled, and yields were suppressed. This might be attributed to the discovery of M. javanica infecting peanut in this field in early autumn 2001. A laboratory test confirmed that although the P. penetrans isolate specific to M. arenaria attached to M. javanica J2, no development occurred. In summary, P. penetrans increased on M. arenaria over a 4-year period, but apparently because of infection of M. javanica on peanut at the field site root-knot disease was not suppressed. This was confirmed by a suppressive soil test that showed a higher level of soil suppressiveness than occurred in the field (P

  8. Persistence and Suppressiveness of Pasteuria penetrans to Meloidogyne arenaria Race

    PubMed Central

    Cetintas, R.; Dickson, D. W.

    2004-01-01

    The long-term persistence and suppressiveness of Pasteuria penetrans against Meloidogyne arenaria race 1 were investigated in a formerly root-knot nematode suppressive site following 9 years of continuous cultivation of three treatments and 4 years of continuous peanut. The three treatments were two M. arenaria race 1 nonhost crops, bahiagrass (Paspalum notatum cv. Pensacola var. Tifton 9), rhizomal peanut (Arachis glabrata cv. Florigraze), and weed fallow. Two root-knot nematode susceptible weeds commonly observed in weed fallow plots were hairy indigo (Indigofera hirsuta) and alyce clover (Alysicarpus vaginalis). The percentage of J2 with endospores attached reached the highest level of 87% in 2000 in weed fallow, and 63% and 53% in 2002 in bahiagrass and rhizomal peanut, respectively. The percentage of endospore-filled females extracted from peanut roots grown in weed fallow plots increased from nondetectable in 1999 to 56% in 2002, whereas the percentages in bahiagrass and rhizomal peanut plots were 41% and 16%, respectively. Over 4 years, however, there was no strong evidence that endospores densities reached suppressive levels because peanut roots, pods, and pegs were heavily galled, and yields were suppressed. This might be attributed to the discovery of M. javanica infecting peanut in this field in early autumn 2001. A laboratory test confirmed that although the P. penetrans isolate specific to M. arenaria attached to M. javanica J2, no development occurred. In summary, P. penetrans increased on M. arenaria over a 4-year period, but apparently because of infection of M. javanica on peanut at the field site root-knot disease was not suppressed. This was confirmed by a suppressive soil test that showed a higher level of soil suppressiveness than occurred in the field (P ≤ 0.01). PMID:19262836

  9. Effect of a formulation of Bacillus firmus on root-knot nematode Meloidogyne incognita infestation and the growth of tomato plants in the greenhouse and nursery.

    PubMed

    Terefe, Metasebia; Tefera, Tadele; Sakhuja, P K

    2009-02-01

    Bacillus firmus, commercial WP formulation (BioNem) was evaluated against the root-knot nematode Meloidogyne incognita in a laboratory, greenhouse and under field conditions on tomato plants. In the laboratory tests, an aqueous suspension of BioNem at 0.5%, 1%, 1.5% and 2% concentration reduced egg hatching from 98% to 100%, 24-days after treatment. Treatment of second-stage juveniles with 2.5% and 3% concentration of BioNem, caused 100% inhibition of mobility, 24 h after treatment. In the green house trials, BioNem applied at 8 g/pot (1200 cc soil) planted with a tomato seedlings reduced gall formation by 91%, final nematode populations by 76% and the number of eggs by 45%. Consequently, plant height and biomass was increased by 71% and 50%, respectively, compared to the untreated control, 50-days after treatment application. Application of BioNem at 16 g/pot was phytotoxic to plants. In the field trails, BioNem applied at 200 and 400 kg ha(-1) was effective in reducing the number of galls (75-84%), and increased shoot height (29-31%) and weight (20-24%) over the untreated control, 45-days after treatment. Our results indicate that B. firmus is a promising microorganism for the biological control of M. incognita in tomato pots.

  10. Response of Resistant and Susceptible Bell Pepper (Capsicum annuum) to a Southern California Meloidogyne incognita Population from a Commercial Bell Pepper Field.

    PubMed

    Aguiar, Jose Luis; Bachie, Oli; Ploeg, Antoon

    2014-12-01

    To determine the presence and level of root-knot nematode (Meloidogyne spp.) infestation in Southern California bell pepper (Capsicum annuum) fields, soil and root samples were collected in April and May 2012 and analyzed for the presence of root-knot nematodes. The earlier samples were virtually free of root-knot nematodes, but the later samples all contained, sometimes very high numbers, of root-knot nematodes. Nematodes were all identified as M. incognita. A nematode population from one of these fields was multiplied in a greenhouse and used as inoculum for two repeated pot experiments with three susceptible and two resistant bell pepper varieties. Fruit yields of the resistant peppers were not affected by the nematodes, whereas yields of two of the three susceptible pepper cultivars decreased as a result of nematode inoculation. Nematode-induced root galling and nematode multiplication was low but different between the two resistant cultivars. Root galling and nematode reproduction was much higher on the three susceptible cultivars. One of these susceptible cultivars exhibited tolerance, as yields were not affected by the nematodes, but nematode multiplication was high. It is concluded that M. incognita is common in Southern California bell pepper production, and that resistant cultivars may provide a useful tool in a nonchemical management strategy.

  11. Resistance-breaking population of Meloidogyne incognita utilizes plant peroxidase to scavenge reactive oxygen species, thereby promoting parasitism on tomato carrying Mi-1 gene.

    PubMed

    Guan, Tinglong; Shen, Jinhua; Fa, Yang; Su, Yishi; Wang, Xuan; Li, Hongmei

    2017-01-01

    Resistance conferred by the Mi-1 gene from Solanum peruvianum is effective and widely used for controlling root-knot nematodes (RKNs, Meloidogyne spp.). However, breakdown of resistance by RKNs seriously threatens the durable application of the resistance resource. Here, a resistance-breaking population of M. incognita was selected from an avirulent population by continuously inoculating on Mi-1-carrying tomato. Histological observations showed the resistance-breaking population would not induce hypersensitive response (HR) when infecting Mi-1-carrying tomato, while avirulent population did. A total of 308 differentially expressed genes (DEGs) were identified from Mi-1-carrying tomato upon infection with resistance-breaking versus avirulent populations by RNA-seq. The expression patterns of 23 selected DEGs were validated by quantitative real-time PCR (qRT-PCR). Subsequently, seven out of nine highly up-regulated DEGs were successfully knocked down in Mi-1-carrying tomato by tobacco rattle virus (TRV) mediated RNAi. The TRV line targeting a peroxidase gene showed a much higher magnitude of reactive oxygen species (ROS) and distinct reduction of pathogenicity upon infection of the resistance-breaking population compared with that of TRV::gfp line. Our results suggested that plant peroxidase might be exploited by resistance-breaking population of M. incognita to scavenge ROS, so as to overcome Mi-1-mediated resistance.

  12. Response of Resistant and Susceptible Bell Pepper (Capsicum annuum) to a Southern California Meloidogyne incognita Population from a Commercial Bell Pepper Field

    PubMed Central

    Aguiar, Jose Luis; Bachie, Oli; Ploeg, Antoon

    2014-01-01

    To determine the presence and level of root-knot nematode (Meloidogyne spp.) infestation in Southern California bell pepper (Capsicum annuum) fields, soil and root samples were collected in April and May 2012 and analyzed for the presence of root-knot nematodes. The earlier samples were virtually free of root-knot nematodes, but the later samples all contained, sometimes very high numbers, of root-knot nematodes. Nematodes were all identified as M. incognita. A nematode population from one of these fields was multiplied in a greenhouse and used as inoculum for two repeated pot experiments with three susceptible and two resistant bell pepper varieties. Fruit yields of the resistant peppers were not affected by the nematodes, whereas yields of two of the three susceptible pepper cultivars decreased as a result of nematode inoculation. Nematode-induced root galling and nematode multiplication was low but different between the two resistant cultivars. Root galling and nematode reproduction was much higher on the three susceptible cultivars. One of these susceptible cultivars exhibited tolerance, as yields were not affected by the nematodes, but nematode multiplication was high. It is concluded that M. incognita is common in Southern California bell pepper production, and that resistant cultivars may provide a useful tool in a nonchemical management strategy. PMID:25580027

  13. Characterization of microRNAs from Arabidopsis galls highlights a role for miR159 in the plant response to the root-knot nematode Meloidogyne incognita.

    PubMed

    Medina, Clémence; da Rocha, Martine; Magliano, Marc; Ratpopoulo, Alizée; Revel, Benoît; Marteu, Nathalie; Magnone, Virginie; Lebrigand, Kevin; Cabrera, Javier; Barcala, Marta; Silva, Ana Cláudia; Millar, Anthony; Escobar, Carolina; Abad, Pierre; Favery, Bruno; Jaubert-Possamai, Stéphanie

    2017-09-14

    Root knot nematodes (RKN) are root parasites that induce the genetic reprogramming of vascular cells into giant feeding cells and the development of root galls. MicroRNAs (miRNAs) regulate gene expression during development and plant responses to various stresses. Disruption of post-transcriptional gene silencing in Arabidopsis ago1 or ago2 mutants decrease the infection rate of RKN suggesting a role for this mechanism in the plant-nematode interaction. By sequencing small RNAs from uninfected Arabidopsis roots and from galls 7 and 14 d post infection with Meloidogyne incognita, we identified 24 miRNAs differentially expressed in gall as putative regulators of gall development. Moreover, strong activity within galls was detected for five miRNA promoters. Analyses of nematode development in an Arabidopsis miR159abc mutant had a lower susceptibility to RKN, suggesting a role for the miR159 family in the plant response to M. incognita. Localization of mature miR159 within the giant and surrounding cells suggested a role in giant cell and gall. Finally, overexpression of miR159 in galls at 14 d post inoculation was associated with the repression of the miR159 target MYB33 which expression is restricted to the early stages of infection. Overall, these results implicate the miR159 in plant responses to RKN. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  14. Knocking-Down Meloidogyne incognita Proteases by Plant-Delivered dsRNA Has Negative Pleiotropic Effect on Nematode Vigor

    PubMed Central

    Antonino de Souza Júnior, José Dijair; Ramos Coelho, Roberta; Tristan Lourenço, Isabela; da Rocha Fragoso, Rodrigo; Barbosa Viana, Antonio Américo; Lima Pepino de Macedo, Leonardo; Mattar da Silva, Maria Cristina; Gomes Carneiro, Regina Maria; Engler, Gilbert; de Almeida-Engler, Janice; Grossi-de-Sa, Maria Fatima

    2013-01-01

    The root-knot nematode Meloidogyne incognita causes serious damage and yield losses in numerous important crops worldwide. Analysis of the M. incognita genome revealed a vast number of proteases belonging to five different catalytic classes. Several reports indicate that M. incognita proteases could play important roles in nematode parasitism, besides their function in ordinary digestion of giant cell contents for feeding. The precise roles of these proteins during parasitism however are still unknown, making them interesting targets for gene silencing to address protein function. In this study we have knocked-down an aspartic (Mi-asp-1), a serine (Mi-ser-1) and a cysteine protease (Mi-cpl-1) by RNAi interference to get an insight into the function of these enzymes during a host/nematode interaction. Tobacco lines expressing dsRNA for Mi-ser-1 (dsSER), Mi-cpl-1 (dsCPL) and for the three genes together (dsFusion) were generated. Histological analysis of galls did not show clear differences in giant cell morphology. Interestingly, nematodes that infected plants expressing dsRNA for proteases produced a reduced number of eggs. In addition, nematode progeny matured in dsSER plants had reduced success in egg hatching, while progeny resulting from dsCPL and dsFusion plants were less successful to infect wild-type host plants. Quantitative PCR analysis confirmed a reduction in transcripts for Mi-cpl-1 and Mi-ser-1 proteases. Our results indicate that these proteases are possibly involved in different processes throughout nematode development, like nutrition, reproduction and embryogenesis. A better understanding of nematode proteases and their possible role during a plant-nematode interaction might help to develop new tools for phytonematode control. PMID:24392004

  15. Evaluation of the Effect of Ecologic on Root Knot Nematode, Meloidogyne incognita, and Tomato Plant, Lycopersicon esculenum

    PubMed Central

    Ladner, Debora C.; Tchounwou, Paul B.; Lawrence, Gary W.

    2008-01-01

    Nonchemical methods and strategies for nematode management including cultural methods and engineered measures have been recommended as an alternative to methyl bromide (a major soil fumigant), due to its role in the depletion of the ozone layer. Hence, an international agreement has recently been reached calling for its reduced consumption and complete phasing out. This present research evaluates the potential of Ecologic, a biological, marine shell meal chitin material, as a soil amendment management agent for root knot nematode, Meloidogyne incognita, control, and its effect on the growth of Floradel tomato plant, Lycopersicon esculentum. To accomplish this goal, studies were conducted during which, experimental pots were set up in greenhouse environments using sterilized soil inoculated with 5,000 root-knot eggs per 1500 g soil. There were 4 treatments and 5 replications. Treatments were: No chitin; 50 g chitin; 100 g chitin; and 200 g chitin. A two-week wait period following Ecologic amendment preceded Floradel tomato planting to allow breakdown of the chitin material into the soil. Fresh and dry weights of shoot and root materials were taken as growth end-points. A statistically significant difference (p ≤ 0.05) was obtained with regard to the growth rate of L. esculentum at 100 g chitin treatment compared to the control with no chitin. Mean fresh weights of Floradel tomato were 78.0 ± 22.3g, 81.0 ± 20.3g, 109.0 ± 25.4g and 102.0 ± 33.3g at 0, 50, 100 and 200g chitin, respectively. The analysis of root knot nematode concentrations indicated a substantial effect on reproduction rate associated with chitin amendment. Study results showed a significant decrease in both root knot nematode eggs and juveniles (J2) at 100g and 200g Ecologic chitin levels, however, an increase in nematode concentrations was recorded at the 50g Ecologic chitin level (p ≤ 0.05). The mean amounts of J2 population, as expressed per 1500cm3 soil, were 49,933 ± 38,819, 86,050

  16. Multiyear evaluation of the durability of the resistance conferred by Ma and RMia genes to Meloidogyne incognita in Prunus under controlled conditions.

    PubMed

    Khallouk, Samira; Voisin, Roger; Portier, Ulysse; Polidori, Joël; Van Ghelder, Cyril; Esmenjaud, Daniel

    2013-08-01

    Root-knot nematodes (RKNs) (Meloidogyne spp.) are highly polyphagous pests that parasitize Prunus crops in Mediterranean climates. Breeding for RKN-resistant Prunus cultivars, as an alternative to the now-banned use of nematicides, is a real challenge, because the perennial nature of these trees increases the risk of resistance breakdown. The Ma plum resistance (R) gene, with a complete spectrum, and the RMia peach R gene, with a more restricted spectrum, both provide total control of Meloidogyne incognita, the model parthenogenetic species of the genus and the most important RKN in terms of economic losses. We investigated the durability of the resistance to this nematode conferred by these genes, comparing the results obtained with those for the tomato Mi-1 reference gene. In multiyear experiments, we applied a high and continuous nematode inoculum pressure by cultivating nematode-infested susceptible tomato plants with either Prunus accessions carrying Ma or RMia R genes, or with resistant tomato plants carrying the Mi-1 gene. Suitable conditions for Prunus development were achieved by carrying out the studies in a glasshouse, in controlled conditions allowing a short winter leaf fall and dormancy. We first assessed the plum accession 'P.2175', which is heterozygous for the Ma gene, in two successive 2-year evaluations, for resistance to two M. incognita isolates. Whatever the isolate used, no nematodes reproducing on P.2175 were detected, whereas galls and nematodes reproducing on tomato plants carrying Mi-1 were observed. In a second experiment with the most aggressive isolate, interspecific full-sib material (P.2175 × ['Garfi' almond × 'Nemared' peach]), carrying either Ma or RMia (from Nemared) or both (in the heterozygous state) or neither of these genes, was evaluated for 4 years. No virulent nematodes developed on Prunus spp. carrying R genes, whereas galling and virulent individuals were observed on Mi-1-resistant tomato plants. Thus, the resistance to

  17. Infection of Seedlings of Alfalfa and Red Clover by Concomitant Populations of Meloidogyne incognita and Pratylenchus penetrans

    PubMed Central

    Turner, Deborah R.; Chapman, R. A.

    1972-01-01

    Invasion of 2-day-old seedlings of 'Buffalo' alfalfa and 'Kenland' red clover by larvae of M. incognita and adults of P. penetrans, during 1-3 day periods of incubation at 24 C, was investigated in 50-mm petri dishes on 1% agar. Penetration by both nematodes increased arithmetically with increased numbers in inocula. P. penetrans invaded alfalfa more readily than red cover, but M. incognita invaded red clover more readily than alfalfa. Both nematodes inhibited root-elongation of alfalfa more than that of red clover. In combinations of 10 and 50 of both nematodes, invasion of both plants by both nematodes was the same as for each nematode alone. Penetration by M. incognita into alfalfa, but not into red clover, was significantly reduced when combinations of 50 M. incognita and 200 P. penetrans were inoculated simultaneously. In the presence of large numbers of entrant P. penetrans in both plants, penetration by M. incognita was highly significantly reduced. Penetration by P. penetrans was unaffected in the reciprocal situations. PMID:19319281

  18. Short interfering RNA-mediated knockdown of drosha and pasha in undifferentiated Meloidogyne incognita eggs leads to irregular growth and embryonic lethality.

    PubMed

    Dalzell, Johnathan J; Warnock, Neil D; Stevenson, Michael A; Mousley, Angela; Fleming, Colin C; Maule, Aaron G

    2010-09-01

    Micro-(mi)RNAs play a pivotal role in the developmental regulation of plants and animals. We reasoned that disruption of normal heterochronic activity in differentiating Meloidogyne incognita eggs may lead to irregular development, lethality and by extension, represent a novel target for parasite control. On silencing the nuclear RNase III enzyme drosha, a critical effector of miRNA maturation in animals, we found a significant inhibition of normal development and hatching in short interfering (si)RNA-soaked M. incognita eggs. Developing juveniles presented with highly irregular tissue patterning within the egg, and we found that unlike our previous gene silencing efforts focused on FMRFamide (Phe-Met-Arg-Phe-NH(2))-like peptides (FLPs), there was no observable phenotypic recovery following removal of the environmental siRNA. Aberrant phenotypes were exacerbated over time, and drosha knockdown proved embryonically lethal. Subsequently, we identified and silenced the drosha cofactor pasha, revealing a comparable inhibition of normal embryonic development within the eggs to that of drosha-silenced eggs, eventually leading to embryonic lethality. To further probe the link between normal embryonic development and the M. incognita RNA interference (RNAi) pathway, we attempted to examine the impact of silencing the cytosolic RNase III enzyme dicer. Unexpectedly, we found a substantial up-regulation of dicer transcript abundance, which did not impact on egg differentiation or hatching rates. Silencing of the individual transcripts in hatched J2s was significantly less successful and resulted in temporary phenotypic aberration of the J2s, which recovered within 24h to normal movement and posture on washing out the siRNA. Soaking the J2s in dicer siRNA resulted in a modest decrease in dicer transcript abundance which had no observable impact on phenotype or behaviour within 48h of initial exposure to siRNA. We propose that drosha, pasha and their ancillary factors may

  19. Suppression Mechanisms of Meloidogyne arenaria Race 1 by Pasteuria penetrans

    PubMed Central

    Chen, Z. X.; Dickson, D. W.; Mitchell, D. J.; McSorley, R.; Hewlett, T. E.

    1997-01-01

    The biological control of Meloidogyne arenaria on peanut (Arachis hypogaea) by Pasteuria penetrans was evaluated using a six x six factorial experiment in field microplots over 2 years. The main factors were six inoculum levels of second-stage juveniles (J2) of M. arenaria race 1 (0, 40, 200, 1,000, 5,000, and 25,000 J2/microplot, except that the highest level was 20,000 J2/microplot in 1995) and six infestation levels of P. penetrans as percentages of J2 with endospores attached (0, 20, 40, 60, 80, and 100%). The results were similar in 1994 and 1995. Numbers of eggs per root system, J2 per 100 cm³ soil at harvest, root galls, and pod galls increased with increasing nematode inoculum levels and decreased with increasing P. penetrans infestation levels (P ≤ 0.05), except that there was no effect of P. penetrans infestation levels on J2 per 100 cm³ soil in 1994 (P> 0.05). There were no statistical interaction effects between the inoculum levels of J2 and the infestation levels of P. penetrans (P > 0.05). When the infestation level was increased by 10%, the number of eggs per root system, root galls, and pod galls decreased 7.8% to 9.4%, 7.0% to 8.5%, and 8.0% to 8.7% in 1994 and 1995, respectively, whereas J2 per 100 cm³ soil decreased 8.8% in 1995 (P ≤ 0.05). The initial infestation level of P. penetrans contributed 81% to 95% of the total suppression of pod galls, whereas the infection of J2 of the subsequent generations contributed only 5% to 19% suppression of pod galls. The major suppressive mechanism of M. arenaria race 1 by P. penetrans on peanut is the initial endospore infestation of J2 at planting. PMID:19274127

  20. Overexpression of MIC-3 indicates a direct role for the MIC gene family in mediating Upland cotton (Gossypium hirsutum) resistance to root-knot nematode (Meloidogyne incognita).

    PubMed

    Wubben, Martin J; Callahan, Franklin E; Velten, Jeff; Burke, John J; Jenkins, Johnie N

    2015-02-01

    Transgene-based analysis of the MIC-3 gene provides the first report of a cotton gene having a direct role in mediating cotton resistance to root-knot nematode. Major quantitative trait loci have been mapped to Upland cotton (Gossypium hirsutum L.) chromosomes 11 and 14 that govern the highly resistant phenotype in response to infection by root-knot nematode (RKN; Meloidogyne incognita); however, nearly nothing is known regarding the underlying molecular determinants of this RKN-resistant phenotype. Multiple lines of circumstantial evidence have strongly suggested that the MIC (Meloidogyne Induced Cotton) gene family plays an integral role in mediating cotton resistance to RKN. In this report, we demonstrate that overexpression of MIC-3 in the RKN-susceptible genetic background Coker 312 reduces RKN egg production by ca. 60-75 % compared to non-transgenic controls and transgene-null sibling lines. MIC-3 transcript and protein overexpression were confirmed in root tissues of multiple independent transgenic lines with each line showing a similar level of increased resistance to RKN. In contrast to RKN fecundity, transgenic lines showed RKN-induced root galling similar to the susceptible controls. In addition, we determined that this effect of MIC-3 overexpression was specific to RKN as no effect was observed on reniform nematode (Rotylenchulus reniformis) reproduction. Transgenic lines did not show obvious alterations in growth, morphology, flowering, or fiber quality traits. Gene expression analyses showed that MIC-3 transcript levels in uninfected transgenic roots exceeded levels observed in RKN-infected roots of naturally resistant plants and that overexpression did not alter the regulation of native MIC genes in the genome. These results are the first report describing a direct role for a specific gene family in mediating cotton resistance to a plant-parasitic nematode.

  1. RNAi-mediated disruption of neuropeptide genes, nlp-3 and nlp-12, cause multiple behavioral defects in Meloidogyne incognita.

    PubMed

    Dash, Manoranjan; Dutta, Tushar K; Phani, Victor; Papolu, Pradeep K; Shivakumara, Tagginahalli N; Rao, Uma

    2017-08-26

    Owing to the current deficiencies in chemical control options and unavailability of novel management strategies, root-knot nematode (M. incognita) infections remain widespread with significant socio-economic impacts. Helminth nervous systems are peptide-rich and appear to be putative drug targets that could be exploited by antihelmintic chemotherapy. Herein, to characterize the novel peptidergic neurotransmitters, in silico mining of M. incognita genomic and transciptomic datasets revealed the presence of 16 neuropeptide-like protein (nlp) genes with structural hallmarks of neuropeptide preproproteins; among which 13 nlps were PCR-amplified and sequenced. Two key nlp genes (Mi-nlp-3 and Mi-nlp-12) were localized to the basal bulb and tail region of nematode body via in situ hybridization assay. Mi-nlp-3 and Mi-nlp-12 were greatly expressed (in qRT-PCR assay) in the pre-parasitic juveniles and adult females, suggesting the association of these genes in host recognition, development and reproduction of M. incognita. In vitro knockdown of Mi-nlp-3 and Mi-nlp-12 via RNAi demonstrated the significant reduction in attraction and penetration of M. incognita in tomato root in Pluronic gel medium. A pronounced perturbation in development and reproduction of NLP-silenced worms was also documented in adzuki beans in CYG growth pouches. The deleterious phenotypes obtained due to NLP knockdown suggests that transgenic plants engineered to express RNA constructs targeting nlp genes may emerge as an environmentally viable option to manage nematode problems in crop plants. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. A gene encoding a peptide with similarity to the plant IDA signaling peptide (AtIDA) is expressed most abundantly in the root-knot nematode (Meloidogyne incognita) soon after root infection.

    PubMed

    Tucker, Mark L; Yang, Ronghui

    2013-06-01

    Small peptides play important roles in intercellular signaling. Inflorescence deficient in abscission (ida) is an Arabidopsis mutant that does not abscise (shed) its flower petals. The IDA gene encodes a small, secreted peptide that putatively binds to two redundant receptor-like kinases (HAESA and HAESA-like2) that initiate a signal transduction pathway. We identified IDA-like (IDL) genes in the genomic sequence for Meloidogyne incognita and Meloidogyne hapla. No orthologous sequences were found in any other genus of nematodes. Transcript for both M. incognita and M. hapla IDLs were found in total RNA isolated from infected root systems of tomato, Solanum lycopersicum. Five and three prime RACE of RNA from M. incognita infected tomato roots revealed a sequence of 392 nt that includes a poly (A) tail of 39 nt. The open reading frame encodes a 47 aa protein with a putative 25 aa N-terminal signal peptide. Expression of MiIDL1 is very low in eggs and pre-parasitic J2 and rapidly increases in the first four days post inoculation (dpi) and then declines at approximately 14 dpi. A proposed role for the root-knot nematode IDL is discussed.

  3. Shifting from priming of salicylic acid- to jasmonic acid-regulated defences by Trichoderma protects tomato against the root knot nematode Meloidogyne incognita.

    PubMed

    Martínez-Medina, Ainhoa; Fernandez, Ivan; Lok, Gerrit B; Pozo, María J; Pieterse, Corné M J; Van Wees, Saskia C M

    2017-02-01

    Beneficial root endophytes such as Trichoderma spp. can reduce infections by parasitic nematodes through triggering host defences. Little is currently known about the complex hormone signalling underlying the induction of resistance. In this study, we investigated whether Trichoderma modulates the hormone signalling network in the host to induce resistance to nematodes. We investigated the role and the timing of the jasmonic acid (JA)- and salicylic acid (SA)-regulated defensive pathways in Trichoderma-induced resistance to the root knot nematode Meloidogyne incognita. A split-root system of tomato (Solanum lycopersicum) was used to study local and systemic induced defences by analysing nematode performance, defence gene expression, responsiveness to exogenous hormone application, and dependence on SA and JA signalling of Trichoderma-induced resistance. Root colonization by Trichoderma impeded nematode performance both locally and systemically at multiple stages of the parasitism, that is, invasion, galling and reproduction. First, Trichoderma primed SA-regulated defences, which limited nematode root invasion. Then, Trichoderma enhanced JA-regulated defences, thereby antagonizing the deregulation of JA-dependent immunity by the nematodes, which compromised galling and fecundity. Our results show that Trichoderma primes SA- and JA-dependent defences in roots, and that the priming of responsiveness to these hormones upon nematode attack is plastic and adaptive to the parasitism stage. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  4. Efficacy of root-associated fungi and PGPR on the growth of Pisum sativum (cv. Arkil) and reproduction of the root-knot nematode Meloidogyne incognita.

    PubMed

    Akhtar, Mohd Sayeed; Panwar, Jitendra

    2013-04-01

    The effects of root-associated fungi (Aspergillus awamori and Glomus mosseae) and plant growth promoting rhizobacteria (PGPR) (Pseudomonas putida, Pseudomonas alcaligenes and Paenibacillus polymyxa) were studied alone and in combination in glasshouse experiments on the growth of pea, enzyme activity (peroxidase and catalase) and reproduction of root-knot nematode Meloidogyne incognita. Application of A. awamori, G. mosseae and PGPR caused a significant increase in pea growth and enzyme activities of both nematode inoculated and uninoculated plants. A. awamori was more effective in reducing galling and improving the growth of nematode inoculated plants than P. alcaligenes or P. polymyxa. The greatest increase in growth, enzyme activities of nematode-inoculated plants and reduction in galling and nematode multiplication was observed when A. awamori was used with P. putida or G. mosseae as compared to the other combinations tested. Percentage root colonization was higher when AM fungus inoculated plants were treated with P. putida both in presence and absence of nematode. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Cloning of the gene Lecanicillium psalliotae chitinase Lpchi1 and identification of its potential role in the biocontrol of root-knot nematode Meloidogyne incognita.

    PubMed

    Gan, Zhongwei; Yang, Jinkui; Tao, Nan; Liang, Lianming; Mi, Qili; Li, Juan; Zhang, Ke-Qin

    2007-10-01

    The nematophagous fungus Lecanicillium psalliotae (syn. Verticillium psalliotae) is a well-known biocontrol agent. In this study, a chitinase gene Lpchi1 was isolated for the first time from L. psalliotae using degenerate primers and DNA-walking technique. The cloned gene Lpchi1 encoding 423 amino acid residues shares a high degree of homology with other pathogenicity-related chitinases from entomopathogenic and mycoparasitic fungi. The complementary DNA sequence of the mature chitinase was amplified via reverse transcription polymerase chain reaction and expressed well in Pichia pastoris GS115. Through gel filtration, the recombinant chitinase was purified as a protein of ca. 45 kDa with an optimal activity at pH 7.0 and 37.6 degrees C. The purified chitinase LPCHI1 was found degrading chitinous components of eggs of the root-knot nematode Meloidogyne incognita and significantly influence its development. Moreover, our results also demonstrate that the protease Ver112 and the chitinase LPCHI1 from the same fungus interacted on the egg infection.

  6. In vitro proteolysis of nematode FMRFamide-like peptides (FLPs) by preparations from a free-living nematode (Panagrellus redivivus) and two plant-parasitic nematodes (Heterodera glycines and Meloidogyne incognita).

    PubMed

    Masler, E P

    2012-03-01

    Proteolytic activities in extracts from three nematodes, the plant parasites Heterodera glycines and Meloidogyne incognita, and the free-living Panagrellus redivivus, were surveyed for substrate preferences using a battery of seven FRET-modified peptide substrates, all derived from members of the large FMRF-amide like peptide (FLP) family in nematodes. Overall protease activity in P. redivivus was four- to fivefold greater than in either of the parasites, a result that might reflect developmental differences. Digestion of the M. incognita FLP KHEFVRFa (substrate Abz-KHEFVRF-Y(3-NO2)a) by M. incognita extract was sevenfold greater than with H. glycines extract and twofold greater than P. redivivus, suggesting species-specific preferences. Additional species differences were revealed upon screening 12 different protease inhibitors. Two substrates were used in the screen, Abz-KHEFVRF-Y(3-NO2)a and Abz-KPSFVRF-Y(3-NO2)a), which was digested equally by all three species. The effects of various inhibitor, substrate and extract source combinations on substrate digestion suggest that M. incognita differs significantly from P. redivivus and H. glycines in its complement of cysteine proteases, particularly cathepsin L-type protease.

  7. Effect of Soil Texture and the Clay Component on Migration of Meloidogyne incognita Second-stage Juveniles

    PubMed Central

    Prot, Jean-Claude; Van Gundy, S. D.

    1981-01-01

    The vertical migration of M. incognita juveniles introduced at 20 cm from the roots was studied in five natural soils, 100% silica sand, 95% silica sand with 5% clay, 90% silica sand with 10% clay, and 95% silica sand with 5% clay as a concentrated layer. In natural soils the percentage of juveniles capable of migrating 20 cm and penetrating the roots decreased when the percentage of clay and silt increased. No migration occurred in silica sand without clay particles; when 5 or 10% of clay were mixed to silica sand, 34 and 26%, respectively, of the juveniles were able to migrate 20 cm. Clay separated from silica sand in which tomatoes were grown was attractive for juveniles. It is suggested that clay particles aid in the migration of root-knot juveniles over long distances to plant roots by absorbing and holding root exudates or bacterial by-products which form a concentration gradient enabling nematodes to locate roots. PMID:19300747

  8. Morphological and Morphometrical Characterization of Meloidogyne incognita from Different Host Plants in Four Districts of Punjab, India

    PubMed Central

    Kaur, Harpreet; Attri, Rajni

    2013-01-01

    The population of M. incognita, the root knot nematode (RKN) was found infesting five different host plants (okra, banana, sunflower, bottle gourd, and brinjal) out of 24 examined from four districts of Punjab, India (Gurdaspur, Ludhiana, Patiala, and Hoshiarpur). Morphological and morphometrical characterization indicated that in the case of mature female, the characters of body length and width, neck length, ratio ‘a’, anus to tail terminus (ATT), interphasmid distance (IPD), and perineal pattern were recorded as stable characters. These taxonomic characters can be reliable for identification. All characters of second-stage juvenile (J2) such as body length, stylet length, head to median bulb length (H-MB), distance from median bulb to excretory pore (MB-EP), tail length, anal body width (ABW), and ratios C and C’ were highly variable. Analysis of interpopulation morphometric characters of mature female of M. incognita, namely, body length, width, and ratio ‘a’ were moderately variable characters (CV 0.26% to 20%) and stylet length, neck length, length of median bulb (LMB), and width of median bulb (WMB) were highly variable (CV 1.0% to 36.1%). In the perineal pattern, the two characters ATT and IPD were moderately variable (CV 8.8% to 17.6%) and two characters, anus to vulval slit (AVS) and length of vulval slit (LVS), were highly variable (CV 2.1% to 40.5%). In J2, body length, stylet length, H-MB, MB-EP, ABW, tail length, ratios C, and C’ were highly variable characters (CV > 12%). PMID:23833327

  9. Morphological and Morphometrical Characterization of Meloidogyne incognita from Different Host Plants in Four Districts of Punjab, India.

    PubMed

    Kaur, Harpreet; Attri, Rajni

    2013-06-01

    The population of M. incognita, the root knot nematode (RKN) was found infesting five different host plants (okra, banana, sunflower, bottle gourd, and brinjal) out of 24 examined from four districts of Punjab, India (Gurdaspur, Ludhiana, Patiala, and Hoshiarpur). Morphological and morphometrical characterization indicated that in the case of mature female, the characters of body length and width, neck length, ratio 'a', anus to tail terminus (ATT), interphasmid distance (IPD), and perineal pattern were recorded as stable characters. These taxonomic characters can be reliable for identification. All characters of second-stage juvenile (J2) such as body length, stylet length, head to median bulb length (H-MB), distance from median bulb to excretory pore (MB-EP), tail length, anal body width (ABW), and ratios C and C' were highly variable. Analysis of interpopulation morphometric characters of mature female of M. incognita, namely, body length, width, and ratio 'a' were moderately variable characters (CV 0.26% to 20%) and stylet length, neck length, length of median bulb (LMB), and width of median bulb (WMB) were highly variable (CV 1.0% to 36.1%). In the perineal pattern, the two characters ATT and IPD were moderately variable (CV 8.8% to 17.6%) and two characters, anus to vulval slit (AVS) and length of vulval slit (LVS), were highly variable (CV 2.1% to 40.5%). In J2, body length, stylet length, H-MB, MB-EP, ABW, tail length, ratios C, and C' were highly variable characters (CV > 12%).

  10. Benzothiadiazole effect in the compatible tomato-Meloidogyne incognita interaction: changes in giant cell development and priming of two root anionic peroxidases.

    PubMed

    Melillo, Maria Teresa; Leonetti, Paola; Veronico, Pasqua

    2014-10-01

    BTH application is effective in root-knot nematode-tomato interaction in a way that involves a delay in the formation of nematode feeding site and triggers molecular responses at several levels. The compatible interaction between root-knot nematodes and their hosts requires the nematode to overcome plant defense systems so that a sophisticated permanent feeding site (giant cells) can be produced within the host roots. It has been suggested that activators of plant defenses may provide a novel management strategy for controlling root-knot nematodes but little is known about the molecular basis by which these elicitors operate. The role of pre-treatment with Benzothiadiazole (BTH), a salicylic acid analog, in inducing resistance against Meloidogyne incognita infection was investigated in tomato roots. A decrease in galling in roots and feeding site numbers was observed following BTH treatment. Histological investigations showed a delay in formation of feeding sites in treated plants. BTH-treated galls had higher H2O2 production, lignin accumulation, and increased peroxidase activity than untreated galls. The expression of two tomato genes, Tap1 and Tap2, coding for anionic peroxidases, was examined by qRT-PCR and in situ hybridization in response to BTH. Tap1 was induced at all infection points, reaching the highest level at 15 dpi. Tap2 expression, although slightly delayed in untreated galls, increased during infection in both treated and untreated galls. The expression of Tap1 and Tap2 was observed in giant cells of untreated roots, whereas the transcripts were localized in both giant cells and in parenchyma cells surrounding the developing feeding sites in treated plants. These results show that BTH applied to tomato plants makes them more resistant to infection by nematodes, which become less effective in overcoming root defense pathway.

  11. Effect of Meloidogyne incognita inoculum density and application rate of Paecilomyces lilacinus strain 251 on biocontrol efficacy and colonization of egg masses analyzed by real-time quantitative PCR.

    PubMed

    Kiewnick, S; Neumann, S; Sikora, R A; Frey, J E

    2011-01-01

    The fungal biocontrol agent, Paecilomyces lilacinus strain 251 (PL251), was evaluated for its potential to control the root-knot nematode Meloidogyne incognita on tomato at varying application rates and inoculum densities. Conversely to previous studies, significant dose-response relationships could not be established. However, we demonstrated that a preplanting soil treatment with the lowest dose of commercially formulated PL251 (2 × 10(5) CFU/g soil) was already sufficient to reduce root galling by 45% and number of egg masses by 69% when averaged over inoculum densities of 100 to 1,600 eggs and infective juveniles per 100 cm(3) of soil. To determine the role of colonization of M. incognita egg masses by PL251 for biocontrol efficacy, a real-time quantitative polymerase chain reaction (PCR) assay with a detection limit of 10 CFU/egg mass was used. Real-time PCR revealed a significant relationship between egg mass colonization by PL251 and the dose of product applied to soil but no correlation was found between fungal density and biocontrol efficacy or nematode inoculum level. These results demonstrate that rhizosphere competence is not the key mode of action for PL251 in controlling M. incognita on tomato.

  12. Assessment of DAPG-producing Pseudomonas fluorescens for management of Meloidogyne incognita and Fusarium oxysporum on watermelon

    USDA-ARS?s Scientific Manuscript database

    Pseudomonas fluorescens isolates Clinto 1R, Wayne 1R and Wood 1R, which produce the antibiotic 2,4-diacetylphloroglucinol (DAPG), can suppress soilborne diseases and promote plant growth. Consequently, these beneficial bacterial isolates were tested on watermelon plants for suppression of Meloidogy...

  13. Greenhouse Studies on the Effect of Marigolds (Tagetes spp.) on Four Meloidogyne Species

    PubMed Central

    Ploeg, Antoon T.

    1999-01-01

    The effects of preplanted marigold on tomato root galling and multiplication of Meloidogyne incognita, M. javanica, M. arenaria, and M. hapla were studied. Marigold cultivars of Tagetes patula, T. erecta, T. signata, and a Tagetes hybrid all reduced galling and numbers of second-stage juveniles in subsequent tomato compared to the tomato-tomato control. All four Meloidogyne spp. reproduced on T. signata 'Tangerine Gem'. Several cultivars of T. patula and T. erecta suppressed galling and reproduction of Meloidogyne spp. on tomato to levels lower than or comparable to a fallow control. Phytotoxic effects of marigold on tomato were not observed. Several of the tested marigold cultivars are ready for full-scale field evaluation against Meloidogyne spp. PMID:19270876

  14. Greenhouse Studies on the Effect of Marigolds (Tagetes spp.) on Four Meloidogyne Species.

    PubMed

    Ploeg, A T

    1999-03-01

    The effects of preplanted marigold on tomato root galling and multiplication of Meloidogyne incognita, M. javanica, M. arenaria, and M. hapla were studied. Marigold cultivars of Tagetes patula, T. erecta, T. signata, and a Tagetes hybrid all reduced galling and numbers of second-stage juveniles in subsequent tomato compared to the tomato-tomato control. All four Meloidogyne spp. reproduced on T. signata 'Tangerine Gem'. Several cultivars of T. patula and T. erecta suppressed galling and reproduction of Meloidogyne spp. on tomato to levels lower than or comparable to a fallow control. Phytotoxic effects of marigold on tomato were not observed. Several of the tested marigold cultivars are ready for full-scale field evaluation against Meloidogyne spp.

  15. Exposure to double-stranded RNA mediated by tobacco rattle virus leads to transcription up-regulation of effector gene Mi-vap-2 from Meloidogyne incognita and promotion of pathogenicity in progeny.

    PubMed

    Chi, Yuankai; Wang, Xuan; Le, Xiuhu; Ju, Yuliang; Guan, Tinglong; Li, Hongmei

    2016-02-01

    Meloidogyne spp. are economically important plant parasites and cause enormous damage to agriculture world-wide. These nematodes use secreted effectors which modify host cells, allowing them to obtain the nutrients required for growth and development. A better understanding of the roles of effectors in nematode parasitism is critical for understanding the mechanisms of nematode-host interactions. In this study, Mi-vap-2 of Meloidogyne incognita, a gene encoding a venom allergen-like protein, was targeted by RNA interference mediated by the tobacco rattle virus. Unexpectedly, compared with a wild type line, a substantial up-regulation of Mi-vap-2 transcript was observed in juveniles collected at 7 days p.i. from Nicotiana benthamiana agroinfiltrated with TRV::vap-2. This up-regulation of the targeted transcript did not impact development of females or the production of galls, nor the number of females on the TRV::vap-2 line. In a positive control line, the transcript of Mi16D10 was knocked down in juveniles from the TRV::16D10 line at 7 days p.i., resulting in a significant inhibition of nematode development. The up-regulation of Mi-vap-2 triggered by TRV-RNAi was inherited by the progeny of the nematodes exposed to double-stranded RNA. Meanwhile, a substantial increase in Mi-VAP-2 expression in those juvenile progeny was revealed by ELISA. This caused an increase in the number of galls (71.2%) and females (84.6%) produced on seedlings of N. benthamiana compared with the numbers produced by control nematodes. Up-regulation of Mi-vap-2 and its encoded protein therefore enhanced pathogenicity of the nematodes, suggesting that Mi-vap-2 may be required for successful parasitism during the early parasitic stage of M. incognita.

  16. Differential Sensitivity of Meloidogyne spp. and Heterodera glycines to Selected Nematicides.

    PubMed

    Gourd, T R; Schmitt, D P; Barker, K R

    1993-12-01

    Differential sensitivity of Meloidogyne arenaria, M. hapla, M. incognita, M. javanica, and Heterodera glycines races 1 and 5 to the nonfumigant nematicides aldicarb, ethoprop, and fenamiphos was evaluated using a 48-hour root-penetration bioassay. Generally, H. glycines was more tolerant of the nematicides, especially ethoprop, than were the Meloidogyne species. Among Meloidogyne species, M. incognita was most sensitive to aldicarb and fenamiphos, but its reaction to ethoprop was similar to the other three Meloidogyne species.

  17. Differential Sensitivity of Meloidogyne spp. and Heterodera glycines to Selected Nematicides

    PubMed Central

    Gourd, T. R.; Schmitt, D. P.; Barker, K. R.

    1993-01-01

    Differential sensitivity of Meloidogyne arenaria, M. hapla, M. incognita, M. javanica, and Heterodera glycines races 1 and 5 to the nonfumigant nematicides aldicarb, ethoprop, and fenamiphos was evaluated using a 48-hour root-penetration bioassay. Generally, H. glycines was more tolerant of the nematicides, especially ethoprop, than were the Meloidogyne species. Among Meloidogyne species, M. incognita was most sensitive to aldicarb and fenamiphos, but its reaction to ethoprop was similar to the other three Meloidogyne species. PMID:19279834

  18. Transcriptome analysis of root-knot nematode (Meloidogyne incognita)-infected tomato (Solanum lycopersicum) roots reveals complex gene expression profiles and metabolic networks of both host and nematode during susceptible and resistance responses.

    PubMed

    Shukla, Neha; Yadav, Rachita; Kaur, Pritam; Rasmussen, Simon; Goel, Shailendra; Agarwal, Manu; Jagannath, Arun; Gupta, Ramneek; Kumar, Amar

    2017-02-21

    Root knot nematodes (RKNs, Meloidogyne incognita) are economically important endoparasites having a wide-host range. We have taken a comprehensive transcriptomic approach to investigate the expression of both tomato and RKN genes in tomato roots at five infection time intervals from susceptible plants and two infection time intervals from resistant plants, grown under soil conditions. Differentially expressed genes during susceptible (1827-tomato, 462-RKN) and resistance (25-tomato, 160-RKN) interactions were identified. In susceptible responses, tomato genes involved in cell wall structure, development, primary and secondary metabolites and defense signalling pathways along with RKN genes involved in host parasitism, development and defense are discussed. In resistance responses, tomato genes involved in secondary metabolite and hormone-mediated defense responses along with RKN genes involved in starvation stress-induced apoptosis are discussed. Also, forty novel differentially expressed RKN genes encoding secretory proteins were identified. Our findings, for the first time, provide novel insights into temporal regulation of genes involved in various biological processes from tomato and RKN simultaneously during susceptible and resistance responses, and reveals involvement of a complex network of biosynthetic pathways during disease development. This article is protected by copyright. All rights reserved.

  19. Suppression of Meloidogyne arenaria Race 1 by Soil Application of Endospores of Pasteuria penetrans

    PubMed Central

    Chen, Z. X.; Dickson, D. W.; McSorley, R.; Mitchell, D. J.; Hewlett, T. E.

    1996-01-01

    The potential of Pasteuria penetrans for suppressing Meloidogyne arenaria race 1 on peanut (Arachis hypogaea) was tested over a 2-year period in a field microplot experiment. Endospores of P. penetrans were mass-produced on M. arenaria race 1 infecting tomato plants. Endospores were inoculated in the first year only at rates of 0, 1,000, 3,000, 10,000, and 100,000 endospores/g of soil, respectively, into the top 20 cm of microplots that were previously infested with M. arenaria race 1. One peanut seedling was planted in each microplot. In the first year, root gall indices and pod galls per microplot were significantly reduced by 60% and 95% for 100,000 endospores/g of soil, and 20% and 65% for 10,000 endospores/g of soil, respectively. Final densities of second-stage juveniles (J2) in soil were not significantly different among the treatments. The number of endospores attached to J2 and percentage of J2 with attached endospores significantly increased with increasing endospore inoculation levels. Pasteuria penetrans significantly reduced the densities of J2 that overwintered. In the second year, root and pod gall indices, respectively, were significantly reduced by 81% and 90% for 100,000 endospores/g of soil, and by 61% and 82% of 10,000 endospores/g of soil. Pod yields were significantly increased by 94% for 100,000 and by 57% for 10,000 endospores/g of soil, respectively. The effect of P. penetrans on final densities of J2 in soil was not significant. Regression analyses verified the role of P. penetrans in the suppression of M. arenaria. The minimum number of endospores required for significantly suppressing M. arenaria race 1 on peanut was 10,000 endospores/g of soil. PMID:19277131

  20. Suppression of Meloidogyne javanica by antagonistic and plant growth-promoting rhizobacteria*

    PubMed Central

    Li, Bin; Xie, Guan-lin; Soad, A.; Coosemans, J.

    2005-01-01

    Four rhizobacteria selected out of over 500 isolates from rhizosphere of the vegetables in China were further studied for suppression of the root-knot nematode and soil-borne fungal pathogens in laboratory and greenhouse in Belgium. They were identified as Brevibacillus brevis or Bacillus subtilis by Biolog test and partial 16s rDNA sequence comparison. They not only inhibited the radial growth of the root-infecting fungi Rhizoctonia solani SX-6, Pythium aphanidermatum ZJP-1 and Fusarium oxysporum f.sp. cucumerinum ZJF-2 in vitro, but also exhibited strong nematicidal activity by killing the second stage larvae of Meloidogyne javanica to varying degrees in the greenhouse. The toxic principles of bacterium B7 that showed the highest juvenile mortality were partially characterized. The active factors were heat stability and resistance to extreme pH values. B7 used either as seed dressing or soil drench significantly reduced the nematode populations in the rhizosphere and enhanced the growth of mungbean plants over the controls in the presence or absence of R. solani. PMID:15909333

  1. Occurrence of Meloidogyne spp. in Argentina

    PubMed Central

    Doucet, M. E.; Pinochet, J.

    1992-01-01

    A record of 84 plant species in 32 families that are hosts to the root-knot nematode species found in Argentina is presented. The genus Meloidogyne appears to be widely distributed in the country, with Meloidogyne incognita and M. javanica the most frequently detected species. Other species found in Argentina include M. arenaria, M. cruciani, M. decalineata, M. hapla, and M. ottersoni. The present survey is supplemented with existing published information. PMID:19283059

  2. Studies on the management of root-knot nematode, Meloidogyne incognita-wilt fungus, Fusarium oxysporum disease complex of green gram, Vigna radiata cv ML-1108

    PubMed Central

    Haseeb, Akhtar; Sharma, Anita; Shukla, Prabhat Kuma

    2005-01-01

    Studies were conducted under pot conditions to determine the comparative efficacy of carbofuran at 1 mg a.i./kg soil, bavistin at 1 mg a.i./kg soil, neem (Azadirachta indica) seed powder at 50 mg/kg soil, green mould (Trichoderma harzianum) at 50.0 ml/kg soil, rhizobacteria (Pseudomonas fluorescens) at 50.0 ml/kg soil against root-knot nematode, Meloidogyne incognita–wilt fungus, Fusarium oxysporum disease complex on green gram, Vigna radiata cv ML-1108. All the treatments significantly improved the growth of the plants as compared to untreated inoculated plants. Analysis of data showed that carbofuran and A. indica seed powder increased plant growth and yield significantly more in comparison to bavistin and P. fluorescens. Carbofuran was highly effective against nematode, bavistin against fungus, A. indica seed powder against both the pathogens and both the bioagents were moderately effective against both the pathogens. PMID:16052706

  3. Genome-wide identification and characterization of miRNAome from tomato (Solanum lycopersicum) roots and root-knot nematode (Meloidogyne incognita) during susceptible interaction

    PubMed Central

    Kaur, Pritam; Shukla, Neha; Joshi, Gopal; VijayaKumar, Cheeni; Jagannath, Arun; Agarwal, Manu; Goel, Shailendra

    2017-01-01

    Root-knot nematodes (RKNs, Meloidogyne spp.) are the most damaging plant parasites causing severe losses to crop production. The present study reports genome-wide identification and characterization of both tomato and RKN miRNAs simultaneously from RKN-infected susceptible tomato roots using high-throughput sequencing technique. RNAseq data from 11 small RNA libraries derived from 5 disease development stages identified 281 novel miRNAs of tomato in addition to 52 conserved and 4 variants of conserved miRNAs. Additionally, the same set of RNAseq data identified 38 conserved and 290 novel RKN miRNAs. Both tomato and RKN miRNAs showed differential expression at 5 stages of disease development based on digital expression profiles. In tomato, further validation through qRT-PCR confirmed that majority of miRNAs were significantly upregulated during susceptible response whereas downregulated during resistance response. The predicted targets of 8 conserved and 1 novel miRNAs were validated through 5’RLM-RACE. A negative correlation between expression profiles of a few conserved miRNAs (miR156, miR159, miR164 and miR396) and their targets (SBP, GAMYB-like, NAC and GRF1 transcription factor) was confirmed. A novel Sly_miRNA996 also showed a negative correlation with its target MYB-like transcription factor. These results indicate that the conserved and novel tomato miRNAs are involved in regulating developmental changes in host root during RKN infection. In RKN, the targets of conserved miRNAs were also predicted and a few of their predicted target genes are known to be involved in nematode parasitism. Further, the potential roles of both tomato and RKN miRNAs have been discussed. PMID:28426683

  4. Genome-wide identification and characterization of miRNAome from tomato (Solanum lycopersicum) roots and root-knot nematode (Meloidogyne incognita) during susceptible interaction.

    PubMed

    Kaur, Pritam; Shukla, Neha; Joshi, Gopal; VijayaKumar, Cheeni; Jagannath, Arun; Agarwal, Manu; Goel, Shailendra; Kumar, Amar

    2017-01-01

    Root-knot nematodes (RKNs, Meloidogyne spp.) are the most damaging plant parasites causing severe losses to crop production. The present study reports genome-wide identification and characterization of both tomato and RKN miRNAs simultaneously from RKN-infected susceptible tomato roots using high-throughput sequencing technique. RNAseq data from 11 small RNA libraries derived from 5 disease development stages identified 281 novel miRNAs of tomato in addition to 52 conserved and 4 variants of conserved miRNAs. Additionally, the same set of RNAseq data identified 38 conserved and 290 novel RKN miRNAs. Both tomato and RKN miRNAs showed differential expression at 5 stages of disease development based on digital expression profiles. In tomato, further validation through qRT-PCR confirmed that majority of miRNAs were significantly upregulated during susceptible response whereas downregulated during resistance response. The predicted targets of 8 conserved and 1 novel miRNAs were validated through 5'RLM-RACE. A negative correlation between expression profiles of a few conserved miRNAs (miR156, miR159, miR164 and miR396) and their targets (SBP, GAMYB-like, NAC and GRF1 transcription factor) was confirmed. A novel Sly_miRNA996 also showed a negative correlation with its target MYB-like transcription factor. These results indicate that the conserved and novel tomato miRNAs are involved in regulating developmental changes in host root during RKN infection. In RKN, the targets of conserved miRNAs were also predicted and a few of their predicted target genes are known to be involved in nematode parasitism. Further, the potential roles of both tomato and RKN miRNAs have been discussed.

  5. A novel Meloidogyne enterolobii effector MeTCTP promotes parasitism by suppressing programmed cell death in host plants.

    PubMed

    Zhuo, Kan; Chen, Jiansong; Lin, Borong; Wang, Jing; Sun, Fengxia; Hu, Lili; Liao, Jinling

    2017-01-01

    Meloidogyne enterolobii is one of the most important plant-parasitic nematodes that can overcome the Mi-1 resistance gene and damage many economically important crops. Translationally controlled tumour protein (TCTP) is a multifunctional protein that exists in various eukaryotes and plays an important role in parasitism. In this study, a novel M. enterolobii TCTP effector, named MeTCTP, was identified and functionally characterized. MeTCTP was specifically expressed within the dorsal gland and was up-regulated during M. enterolobii parasitism. Transient expression of MeTCTP in protoplasts from tomato roots showed that MeTCTP was localized in the cytoplasm of the host cells. Transgenic Arabidopsis thaliana plants overexpressing MeTCTP were more susceptible to M. enterolobii infection than wild-type plants in a dose-dependent manner. By contrast, in planta RNA interference (RNAi) targeting MeTCTP suppressed the expression of MeTCTP in infecting nematodes and attenuated their parasitism. Furthermore, MeTCTP could suppress programmed cell death triggered by the pro-apoptotic protein BAX. These results demonstrate that MeTCTP is a novel plant-parasitic nematode effector that promotes parasitism, probably by suppressing programmed cell death in host plants. © 2016 BSPP and John Wiley & Sons Ltd.

  6. Effect of Carbamate, Organophosphate, and Avermectin Nematicides on Oxygen Consumption by Three Meloidogyne spp.

    PubMed

    Nordmeyer, D; Dickson, D W

    1989-10-01

    Second-stage juveniles (I2) of Meloidogyne arenaria consumed more oxygen (P incognita J2, which in turn consumed more than M. javanica J2 (4,820, 4,530, and 3,970 mul per hour per g nematode dryweight, respectively). Decrease in oxygen consumption depended on the nematicide used. Except for aldicarb, there was no differential sensitivity among the three nematode species. Meloidogyne javanica had a greater percentage decrease (P incognita. Meloidogyne javanica J2 had a greater degree of recovery from fenamiphos or aldicarb intoxication, after subsequent transfer to water, than did M. incognita. This finding may relate to differential sensitivity among Meloidogyne spp. in the field. Degree of respiratory inhibition and loss of nematode motility for M. javanica after exposure to the nematicides were positively correlated (P

  7. Crop Rotation and Nematicides for Management of Mixed Populations of Meloidogyne spp. on Tobacco.

    PubMed

    Fortnum, B A; Lewis, S A; Johnson, A W

    2001-12-01

    The effects of crop rotation and the nematicides 1,3-dichloropropene (1,3-D), ethoprop, and fenamiphos on the relative frequency of Meloidogyne incognita race 3, M. arenaria race 2, and M. javanica and tobacco yields on a sandy loam soil were determined. Cropping sequences altered the species composition and population densities of Meloidogyne spp. Meloidogyne arenaria and M. incognita predominated when cotton, corn, sorghum, or rye-fallow preceded tobacco. Meloidogyne javanica and M. arenaria predominated when tobacco preceded tobacco. Sorghum, cotton, corn, or rye-fallow preceding tobacco enhanced yields compared to tobacco preceding tobacco in plots containing mixtures of Meloidogyne species. Sorghum supported minimal reproduction of any Meloidogyne spp. Application of 1,3-D increased tobacco yields and reduced root galling when compared to untreated controls. Both fenamiphos and ethoprop treatments were less effective than 1,3-D in controlling Meloidogyne spp. or increasing yields. A rotation crop x nematicide interaction was not observed. In continuous tobacco, use of the M. incognita-resistant tobacco cv. Coker 176 increased tobacco yields when compared to the M. incognita-susceptible cv. Coker 319 when 1,3-D was not applied.

  8. Suppression of Meloidogyne hapla and Its Damage to Lettuce Grown in a Mineral Soil Amended with Chitin and Biocontrol Organisms

    PubMed Central

    Chen, J.; Abawi, G. S.; Zuckerman, B. M.

    1999-01-01

    Chitin was used as soil amendment in fiberglass field microplots, alone or with one or a combination of two to three species of Hirsutella rhossiliensis, Paecilomyces marquandii, Verticillium chlamydosporium, Bacillus thuringiensis, and Streptomyces costaricanus. Sudangrass and rapeseed were planted as cover crops and incorporated into soil as green manure amendments. Chitin amendment alone increased the marketable yield of lettuce in 1995 and reduced root-galling ratings and the reproduction of Meloidogyne hapla in both 1995 and 1996. Green manure amendments of sudangrass and rapeseed increased total and marketable yields of lettuce, and decreased root-galling ratings and the reproduction of M. hapla in 1996. Hirsutella rhossiliensis in combination with chitin increased total yield of lettuce over the chitin amendment alone in 1995. The combination of B. thuringiensis, S. costaricanus, and chitin either with or without P. marquandii increased total yield of lettuce over the chitin amendment alone in 1996. In most cases, however, the nematode-antagonistic organisms did not improve lettuce yield or further suppression of M. hapla compared to the chitin amendment alone. The introduced fungi were recoverable from the infested soil. The rifampicin-resistant mutant of B. thuringiensis was not isolated at the end of the season. PMID:19270942

  9. Expression of Arabidopsis genes AtNPR1 and AtTGA2 in transgenic soybean roots of composite plants confers resistance to root-knot nematode (Meloidogyne incognita)

    USDA-ARS?s Scientific Manuscript database

    Root-knot nematodes (RKN; Meloidogyne spp.) are among the most destructive of the plant parasitic nematodes, infecting almost all cultivated plants and resulting in yield losses of billions of dollars annually. NPR1 (nonexpresser of pathogenesis related genes 1, AtNPR1) plays a positive role in the ...

  10. Evaluation of Pochonia chlamydosporia and Purpureocillium lilacinum for Suppression of Meloidogyne enterolobii on Tomato and Banana

    PubMed Central

    Silva, Silas D.; Carneiro, Regina M. D. G.; Faria, Marcos; Souza, Daniela A.; Monnerat, Rose G.; Lopes, Rogerio B.

    2017-01-01

    Meloidogyne enterolobii is one of the most important root-knot nematode in tropical regions, due to its ability to overcome resistance mechanisms of a number of host plants. The lack of new and safe active ingredients against this nematode has restricted control alternatives for growers. Egg-parasitic fungi have been considered as potential candidates for the development of bionematicides. In tissue culture plates, Pochonia chlamydosporia (var. catenulata and chlamydosporia) and Purpureocillium lilacinum strains were screened for their ability to infect eggs of the root-knot nematode M. enterolobii on water-agar surfaces. Reduction in the hatching of J2 varied from 13% to 84%, depending on strain. The more efficacious strains reduced hatchability of J2 by 57% to 84% when compared to untreated eggs, but average reductions were only 37% to 55% when the same strains were applied to egg masses. Combinations of fungal isolates (one of each species) did not increase the control efficacy in vitro. In experiments in which 10,000 nematode eggs were inoculated per plant, reductions in the number of eggs after 12 months were seen in three of four treatments in banana plants, reaching 34% for P. chlamydosporia var. catenulata. No significant reductions were seen in tomato plants after 3 mon. In another experiment with tomato plants using either P. chlamydosporia var. catenulata or P. lilacinum, the number of eggs was reduced by 34% and 44%, respectively, when initial infestation level was low (500 nematode eggs per plant), but tested strains were not effective under a moderate infestation level (5,000 eggs per plant). Under all infestation levels tested in this work, gall and egg mass indexes (MI) did not differ from the untreated controls, bringing concerns related to the practical adoption of this control strategy by farmers. In our opinion, if the fungi P. chlamydosporia and P. lilacinum are to be used as biocontrol tools toward M. entorolobii, they should focus on

  11. Studies onPaecilomyces marquandii from nematode suppressive chinampa soils.

    PubMed

    Marban-Mendoza, N; Garcia-E, R; Dicklow, M B; Zuckerman, B M

    1992-05-01

    Two applications of isolates ofPaecilomyces marquandii from suppressive chinampa soils or P. lilacinus from Peru, fungi that parasitize nematode eggs, generally gave better control of tomato root-knot due toMeloidogyne incognita than did a single application. The effects on root galling by each of thePaecilomyces isolates varied between experiments; however, the ovicidal potential of the three isolates did not differ significantly. Proteins specific for each of the isolates were demonstrated by SDS gel electrophoresis. The results indicate thatP. marquandii is one of the natural soil organisms that contribute to nematode suppression in the chinampa agricultural soils.

  12. Induced Resistance to Meloidogyne hapla by other Meloidogyne species on Tomato and Pyrethrum Plants

    PubMed Central

    Ogallo, J. L.; McClure, M. A.

    1995-01-01

    Advance inoculation of the tomato cv. Celebrity or the pyrethrum clone 223 with host-incompatible Meloidogyne incognita or M. javanica elicited induced resistance to host-compatible M. hapla in pot and field experiments. Induced resistance increased with the length of the time between inoculations and with the population density of the induction inoculum. Optimum interval before challenge inoculation, or population density of inoculum for inducing resistance, was 10 days, or 5,000 infective nematodes per 500-cm³ pot. The induced resistance suppressed population increase of M. hapla by 84% on potted tomato, 72% on potted pyrethrum, and 55% on field-grown pyrethrum seedlings, relative to unprotected treatments. Pyrethrum seedlings inoculated with M. javanica 10 days before infection with M. hapla were not stunted, whereas those that did not receive the advance inoculum were stunted 33% in pots and 36% in field plots. The results indicated that advance infection of plants with incompatible or mildly virulent nematode species induced resistance to normally compatible nematodes and that the induced resistance response may have potential as a biological control method for plant nematodes. PMID:19277310

  13. Survey of Meloidogyne spp. in Tomato Production Fields of Baix Llobregat County, Spain

    PubMed Central

    Sorribas, F. J.; Verdejo-Lucas, S.

    1994-01-01

    A survey was conducted to determine the frequency and abundance of Meloidogyne spp. in tomato production sites located in Baix Llobregat County, Barcelona, Spain. Forty-five sites were sampled before planting and at harvest from February to October, 1991. Meloidogyne spp. occurred in 49% of the sites sampled. Preplant population densities ranged from 10 to 220 (x̄ = 110)juveniles/ 250 cm³ soil, and final population densities ranged from 20 to 1,530 (x̄ = 410)juveniles/250 cm³ soil. Final population densities were higher in open fields than in field greenhouses, but initial population densities were higher in greenhouses than in fields. Meloidogyne incognita, M. javanica, and M. arenaria were found in this survey. Meloidogyne populations that reproduced on M. incognita-resistant tomato cultivars in the field sites did not circumvent the Mi gene resistance in greenhouse tests. PMID:19279955

  14. Meloidogyne partityla on Pecan Isozyme Phenotypes and Other Host.

    PubMed

    Starr, J L; Tomaszewski, E K; Mundo-Ocampo, M; Baldwin, J G

    1996-12-01

    Meloidogyne sp. from five pecan (Carya illinoensis) orchards in Texas were distinctive in host range and iszoyme profiles from common species of Meloidogyne but were morphologically congruent with Meloidogyne partityla Kleynhans, a species previously known only in South Africa. In addition to pecan, species of walnut (Juglans hindsii and J. regia) and hickory (C. ovata) also were hosts. No reproduction was observed on 15 other plant species from nine families, including several common hosts of other Meloidogyne spp. Three esterase phenotypes and two malate dehydrogenase phenotypes of M. partityla were identified by polyacrylamide gel electrophoresis. Each of these isozyme phenotypes was distinct from those of the more common species M. arenaria, M. hapla, M. incognita, and M. javanica.

  15. Meloidogyne partityla on Pecan Isozyme Phenotypes and Other Host

    PubMed Central

    Starr, J. L.; Tomaszewski, E. K.; Mundo-Ocampo, M.; Baldwin, J. G.

    1996-01-01

    Meloidogyne sp. from five pecan (Carya illinoensis) orchards in Texas were distinctive in host range and iszoyme profiles from common species of Meloidogyne but were morphologically congruent with Meloidogyne partityla Kleynhans, a species previously known only in South Africa. In addition to pecan, species of walnut (Juglans hindsii and J. regia) and hickory (C. ovata) also were hosts. No reproduction was observed on 15 other plant species from nine families, including several common hosts of other Meloidogyne spp. Three esterase phenotypes and two malate dehydrogenase phenotypes of M. partityla were identified by polyacrylamide gel electrophoresis. Each of these isozyme phenotypes was distinct from those of the more common species M. arenaria, M. hapla, M. incognita, and M. javanica. PMID:19277175

  16. Effect of Crop Rotation on Meloidogyne spp. and Pratylenchus spp. Populations in Strawberry Fields in Taiwan

    PubMed Central

    Chen, P.; Tsay, T.T.

    2006-01-01

    Changes in population levels of Meloidogyne hapla, M. incognita, Pratylenchus coffeae, and P. penetrans were studied in 12 strawberry fields in the Dahu region of Taiwan. Ten potential rotation crops and two cultural practices were evaluated for their effect on nematode populations and influence on strawberry yield. Rotation with rice or taro and the cultural practice of flooding and bare fallowing for four months were found to reduce nematode soil populations to two or fewer nematodes per 100 ml soil. Average strawberry yields increased between 2.4% to 6.3% following taro compared to the bare fallow treatment. Corn suppressed M. incognita and M. hapla populations and resulted in an increased in strawberry yield compared to bare fallow. Other phytopathogens also present in these fields limited taro as the rotation choice for nematode management. Results of this research and economic analysis of the input requirements for various rotation crops, corn and bare fallow were recommended as the most appropriate rotation strategies for nematode management in strawberry in this region. PMID:19259538

  17. Effect of Crop Rotation on Meloidogyne spp. and Pratylenchus spp. Populations in Strawberry Fields in Taiwan.

    PubMed

    Chen, P; Tsay, T T

    2006-09-01

    Changes in population levels of Meloidogyne hapla, M. incognita, Pratylenchus coffeae, and P. penetrans were studied in 12 strawberry fields in the Dahu region of Taiwan. Ten potential rotation crops and two cultural practices were evaluated for their effect on nematode populations and influence on strawberry yield. Rotation with rice or taro and the cultural practice of flooding and bare fallowing for four months were found to reduce nematode soil populations to two or fewer nematodes per 100 ml soil. Average strawberry yields increased between 2.4% to 6.3% following taro compared to the bare fallow treatment. Corn suppressed M. incognita and M. hapla populations and resulted in an increased in strawberry yield compared to bare fallow. Other phytopathogens also present in these fields limited taro as the rotation choice for nematode management. Results of this research and economic analysis of the input requirements for various rotation crops, corn and bare fallow were recommended as the most appropriate rotation strategies for nematode management in strawberry in this region.

  18. Detection of Invertebrate Suppressive Soils, and Identification of a Possible Biological Control Agent for Meloidogyne Nematodes Using High Resolution Rhizosphere Microbial Community Analysis

    PubMed Central

    Bell, Nigel L.; Adam, Katharine H.; Jones, Rhys J.; Johnson, Richard D.; Mtandavari, Yeukai F.; Burch, Gabriela; Cave, Vanessa; Cameron, Catherine; Maclean, Paul; Popay, Alison J.; Fleetwood, Damien

    2016-01-01

    White clover (Trifolium repens) is the key legume component of New Zealand pastoral agriculture due to the high quality feed and nitrogen inputs it provides. Invertebrate pests constrain white clover growth and this study investigated rhizosphere-associated fungal controls for two of these pests and attempts to disentangle the underpinning mechanisms. The degree of suppressiveness of 10 soils, in a latitudinal gradient down New Zealand, to added Meloidogyne hapla and Costelytra zealandica scarab larvae was measured in untreated soil. Most of the soils showed no suppressive activity against these pests but two showed activity against M. hapla and two against C. zealandica. Rhizosphere fungi responsible for pest suppressive responses were elucidated via next-generation sequencing. In the M. hapla-suppressive soils nematode-trapping Orbiliomycetes fungi were present in significantly greater abundance than non-suppressive soils and their abundance increased further with addition of M. hapla. A comparison of plant growth and the rhizosphere fungal community between untreated and irradiated soil was carried out on 5 of the 10 soils using Pyronota as the scarab larvae. Soil irradiation either: reduced (by 60–70%); increased (16×) or made no difference to white clover growth across the five soils tested, illustrating the range of microbial impacts on plant production. In one of the M. hapla suppressive soils irradiation resulted in a significant increase in nematode galling suggesting that Orbiliomycetes fungi were indeed responsible for the suppressive effect. Lack of consistent changes in soil macronutrients and pH post-irradiation suggest these were not responsible for plant or invertebrate responses. The use of next generation sequencing in controlled pot trials has allowed identification of a potential biological control organism and bioindicator for M. hapla suppression. PMID:28082997

  19. Evidence of Differences between the Communities of Arbuscular Mycorrhizal Fungi Colonizing Galls and Roots of Prunus persica Infected by the Root-Knot Nematode Meloidogyne incognita▿

    PubMed Central

    Alguacil, Maria del Mar; Torrecillas, Emma; Lozano, Zenaida; Roldán, Antonio

    2011-01-01

    Arbuscular mycorrhizal fungi (AMF) play important roles as plant protection agents, reducing or suppressing nematode colonization. However, it has never been investigated whether the galls produced in roots by nematode infection are colonized by AMF. This study tested whether galls produced by Meloidogyne incognita infection in Prunus persica roots are colonized by AMF. We also determined the changes in AMF composition and biodiversity mediated by infection with this root-knot nematode. DNA from galls and roots of plants infected by M. incognita and from roots of noninfected plants was extracted, amplified, cloned, and sequenced using AMF-specific primers. Phylogenetic analysis using the small-subunit (SSU) ribosomal DNA (rDNA) data set revealed 22 different AMF sequence types (17 Glomus sequence types, 3 Paraglomus sequence types, 1 Scutellospora sequence type, and 1 Acaulospora sequence type). The highest AMF diversity was found in uninfected roots, followed by infected roots and galls. This study indicates that the galls produced in P. persica roots due to infection with M. incognita were colonized extensively by a community of AMF, belonging to the families Paraglomeraceae and Glomeraceae, that was different from the community detected in roots. Although the function of the AMF in the galls is still unknown, we hypothesize that they act as protection agents against opportunistic pathogens. PMID:21984233

  20. Assessment of selected pecan and peach rootstocks for resistance to Meloidogyne partityla

    USDA-ARS?s Scientific Manuscript database

    Open pollinated pecan seedling rootstocks were evaluated for susceptibility to Meloidogyne partityla, M. arenaria, and M. incognita in the greenhouse. Cultivars tested included seed from ‘Apache’, ‘Caddo’, ‘Curtis’, ‘Moneymaker’, ‘Pawnee’, ‘Schley’, ‘Stuart’, and ‘Wichita’ parent trees. ‘Elliott’...

  1. Pathogenicity and control of Heterodera schachtii and Meloidogyne spp. on some cruciferous plant cultivars

    USDA-ARS?s Scientific Manuscript database

    The pathogenicity of the sugar beet cyst nematode Heterodera schachtii and the root-knot nematodes Meloidogyne arenaria, M. incognita and M. javanica on cabbage cvs. Balady, Brunswick and Ganzouri, cauliflower cv. Balady, turnip cv. Balady, and radish cv. Balady was determined in several greenhouse ...

  2. Mitochondrial Haplotype-based Identification of Root-knot Nematodes (Meloidogyne spp.) on Cut Foliage Crops in Florida

    PubMed Central

    Baidoo, Richard; Joseph, Soumi; Mengistu, Tesfamariam M.; Brito, Janete A.; McSorley, Robert; Stamps, Robert H.; Crow, William T.

    2016-01-01

    Florida accounts for more than 75% of the national cut foliage production. Unfortunately, root-knot nematodes (RKN) (Meloidogyne spp.) are a serious problem on these crops, rendering many farms unproductive. Currently, information on the Meloidogyne spp. occurring on most commonly cultivated cut foliage crops in Florida, and tools for their rapid identification are lacking. The objectives of this study were to (i) identify specific RKN infecting common ornamental cut foliage crops in Florida and (ii) evaluate the feasibility of using the mtDNA haplotype as a molecular diagnostic tool for rapid identification of large samples of RKN. A total of 200 Meloidogyne females were collected from cut foliage plant roots. Meloidogyne spp. were identified by PCR and RFLP of mitochondrial DNA. PCR and RFLP of mitochondrial DNA were effective in discriminating the Meloidogyne spp. present. Meloidogyne incognita is the most dominant RKN on cut foliage crops in Florida and must be a high target for making management decisions. Other Meloidogyne spp. identified include M. javanica, M. hapla, Meloidogyne sp. 1, and Meloidogyne sp. 2. The results for this study demonstrate the usefulness of the mtDNA haplotype-based designation as a valuable molecular tool for identification of Meloidogyne spp. PMID:27765993

  3. A novel Meloidogyne graminicola effector, MgGPP, is secreted into host cells and undergoes glycosylation in concert with proteolysis to suppress plant defenses and promote parasitism.

    PubMed

    Chen, Jiansong; Lin, Borong; Huang, Qiuling; Hu, Lili; Zhuo, Kan; Liao, Jinling

    2017-04-01

    Plant pathogen effectors can recruit the host post-translational machinery to mediate their post-translational modification (PTM) and regulate their activity to facilitate parasitism, but few studies have focused on this phenomenon in the field of plant-parasitic nematodes. In this study, we show that the plant-parasitic nematode Meloidogyne graminicola has evolved a novel effector, MgGPP, that is exclusively expressed within the nematode subventral esophageal gland cells and up-regulated in the early parasitic stage of M. graminicola. The effector MgGPP plays a role in nematode parasitism. Transgenic rice lines expressing MgGPP become significantly more susceptible to M. graminicola infection than wild-type control plants, and conversely, in planta, the silencing of MgGPP through RNAi technology substantially increases the resistance of rice to M. graminicola. Significantly, we show that MgGPP is secreted into host plants and targeted to the ER, where the N-glycosylation and C-terminal proteolysis of MgGPP occur. C-terminal proteolysis promotes MgGPP to leave the ER, after which it is transported to the nucleus. In addition, N-glycosylation of MgGPP is required for suppressing the host response. The research data provide an intriguing example of in planta glycosylation in concert with proteolysis of a pathogen effector, which depict a novel mechanism by which parasitic nematodes could subjugate plant immunity and promote parasitism and may present a promising target for developing new strategies against nematode infections.

  4. Diversity of Meloidogyne spp. on Musa in Martinique, Guadeloupe, and French Guiana

    PubMed Central

    Cofcewicz, E. T.; Carneiro, R. M. D. G.; Randig, O.; Chabrier, C.; Quénéhervé, P.

    2005-01-01

    Ninety-six isolates of Meloidogyne species collected from banana fields from Martinique, Guadeloupe, and French Guiana, were examined using esterase (Est) and malate dehydrogenase (Mdh) phenotypes. Adult females identified as M. arenaria, M. incognita, M. javanica, M. cruciani, M. hispanica, and Meloidogyne sp. showed species-specific phenotypes only for the esterase enzymes. Intraspecific variability among isolates of M. arenaria, M. incognita, and M. javanica was detected using Est and Mdh. Perineal patterns were used as a complementary tool together with enzyme characterization and were essential for checking the morphological consistency of the identification. The major species of M. arenaria and M. incognita were detected at 61.9% and 34.3% of the total number of isolates, respectively, and the other minor species at 3.8%. The mixed Meloidogyne species were detected in 45.1% of the samples. Genetic analysis was conducted using RAPD markers, which alone or in combination provided reliable polymorphisms both between and within species. RAPD analysis of the data resulted in clustering of species and isolates congruent with esterase phenotype characterization. The intraspecific variability in M. incognita and in M. arenaria represented 14.9% and 61.6% of the amplified polymorphic fragments, respectively. This high level of variation in M. arenaria isolates may indicate multiple origins for populations classified as M. arenaria or more than one species inside the same group, but more detailed morphological and DNA studies will be necessary to test this hypothesis. PMID:19262879

  5. Diversity of Meloidogyne spp. on Musa in Martinique, Guadeloupe, and French Guiana.

    PubMed

    Cofcewicz, E T; Carneiro, R M D G; Randig, O; Chabrier, C; Quénéhervé, P

    2005-09-01

    Ninety-six isolates of Meloidogyne species collected from banana fields from Martinique, Guadeloupe, and French Guiana, were examined using esterase (Est) and malate dehydrogenase (Mdh) phenotypes. Adult females identified as M. arenaria, M. incognita, M. javanica, M. cruciani, M. hispanica, and Meloidogyne sp. showed species-specific phenotypes only for the esterase enzymes. Intraspecific variability among isolates of M. arenaria, M. incognita, and M. javanica was detected using Est and Mdh. Perineal patterns were used as a complementary tool together with enzyme characterization and were essential for checking the morphological consistency of the identification. The major species of M. arenaria and M. incognita were detected at 61.9% and 34.3% of the total number of isolates, respectively, and the other minor species at 3.8%. The mixed Meloidogyne species were detected in 45.1% of the samples. Genetic analysis was conducted using RAPD markers, which alone or in combination provided reliable polymorphisms both between and within species. RAPD analysis of the data resulted in clustering of species and isolates congruent with esterase phenotype characterization. The intraspecific variability in M. incognita and in M. arenaria represented 14.9% and 61.6% of the amplified polymorphic fragments, respectively. This high level of variation in M. arenaria isolates may indicate multiple origins for populations classified as M. arenaria or more than one species inside the same group, but more detailed morphological and DNA studies will be necessary to test this hypothesis.

  6. Evaluation of Cover Crops with Potential for Use in Anaerobic Soil Disinfestation (ASD) for Susceptibility to Three Species of Meloidogyne

    USDA-ARS?s Scientific Manuscript database

    Several cover crops with potential for use in tropical and subtropical regions were assessed for susceptibility to three common species of root-knot nematode, Meloidogyne arenaria, M. incognita, and M. javanica. Crops were selected based on potential use as organic amendments in anaerobic soil disin...

  7. Effects of cover crops with potential for use in anaerobic soil disinfestation (asd) on reproduction of meloidogyne spp.

    USDA-ARS?s Scientific Manuscript database

    Several cover crops were assessed for their susceptibility to invasion and galling by three species of root-knot nematode, Meloidogyne arenaria, M. incognita, and M. javanica. Crops were selected based on their potential for use as the organic amendment component in anaerobic soil disinfestation (AS...

  8. Inheritance and mapping of Mj-2, a new source of root-knot nematode (Meloidogyne javanica) resistance in carrot

    USDA-ARS?s Scientific Manuscript database

    Root-knot nematodes limit carrot production around the world by inducing taproot forking and galling deformities that render carrots unmarketable. In warmer climates, Meloidogyne javanica and M. incognita are most prevalent. In F2 and F3 progeny from the cross between an Asian carrot resistant to M....

  9. Terra Incognita I

    NASA Astrophysics Data System (ADS)

    Lindner, M.; Schönert, S.

    2005-08-01

    The topics discussed in the workshop session "Terra Incognita I" included a wide range of science. Central to the discussion however was the study of sub-leading neutrino oscillations driven by Θ 13 and the possibility to observe CP-violation in the leptonic sector. Furthermore, the long-standing problem of sterile neutrinos was addressed, as well as the scenario that UHECR could be produced via so called Z-bursts. To employ neutrinos in the literal meaning of the workshop session title "Terra Incognita", namely to explore the unknown earth with neutrinos from geo-chemical origin, completed the session.

  10. A novel Meloidogyne graminicola effector, MgGPP, is secreted into host cells and undergoes glycosylation in concert with proteolysis to suppress plant defenses and promote parasitism

    PubMed Central

    Huang, Qiuling; Hu, Lili; Zhuo, Kan

    2017-01-01

    Plant pathogen effectors can recruit the host post-translational machinery to mediate their post-translational modification (PTM) and regulate their activity to facilitate parasitism, but few studies have focused on this phenomenon in the field of plant-parasitic nematodes. In this study, we show that the plant-parasitic nematode Meloidogyne graminicola has evolved a novel effector, MgGPP, that is exclusively expressed within the nematode subventral esophageal gland cells and up-regulated in the early parasitic stage of M. graminicola. The effector MgGPP plays a role in nematode parasitism. Transgenic rice lines expressing MgGPP become significantly more susceptible to M. graminicola infection than wild-type control plants, and conversely, in planta, the silencing of MgGPP through RNAi technology substantially increases the resistance of rice to M. graminicola. Significantly, we show that MgGPP is secreted into host plants and targeted to the ER, where the N-glycosylation and C-terminal proteolysis of MgGPP occur. C-terminal proteolysis promotes MgGPP to leave the ER, after which it is transported to the nucleus. In addition, N-glycosylation of MgGPP is required for suppressing the host response. The research data provide an intriguing example of in planta glycosylation in concert with proteolysis of a pathogen effector, which depict a novel mechanism by which parasitic nematodes could subjugate plant immunity and promote parasitism and may present a promising target for developing new strategies against nematode infections. PMID:28403192

  11. Penetration Rates by Second-stage Juveniles of Meloidogyne spp. and Heterodera glycines into Soybean Roots

    PubMed Central

    Gourd, T. R.; Schmitt, D. P.; Barker, K. R.

    1993-01-01

    The rates of soybean root penetration by freshly hatched second-stage juveniles (J2) of Meloidogyne arenaria, M. hapla, M. incognita, M. javanica, and Heterodera glycines races 1 and 5 were examined over a period of 1 to 240 hours. Heterodera glycines entered roots more quickly than Meloidogyne spp. Penetration by most nematodes was accomplished within 48 hours. The increases in penetration after 48 hours were insufficient to warrant further assessments. Penetration of J2 into roots of soybean seedfings in a styrofoam container was as good or better than in a clay pot. Thus, rapid and accurate root-penetration assessments can be made at 48 hours after inoculation. PMID:19279739

  12. MiRNAs from cotton roots infected with Meloidogyne incognita

    USDA-ARS?s Scientific Manuscript database

    The molecular activities associated with the resistance of Upland cotton (Gossypium hirsutum L.) to the root-knot nematode (RKN) are largely unknown. Small RNAs or microRNAs (miRNA), a well-conserved gene regulatory system, have an important role in plant development, stress responses, and epigeneti...

  13. Response of Meloidogyne spp., Heterodera glycines, and Radopholus similis to Tannic Acid.

    PubMed

    Hewlett, T E; Hewlett, E M; Dickson, D W

    1997-12-01

    Tannins, which are water-soluble polyphenols, are toxic to numerous fungi, bacteria, and yeasts. Our objectives were to study the efficacy of tannic acid in control of Meloidogyne arenaria on tomato and its effects on the behavior of M. arenaria, M. incognita, Heterodera glycines, and Radopholus similis. Three concentrations of tannic acid, 0.1, 1.0, and 10 g/500 cm(3) of soil, were applied preplant (powder) and at-plant (powder and drench) into soil infested with M. arenaria. Tannic acid at the 1.0-g rate reduced galling compared with the untreated control, regardless of methods of application. The 0.1-g rate resulted in no reduction in galling when applied preplant but reduced galling when applied as a drench and in one of two experiments when applied at-plant. The 10-g rate was phytotoxic to tomato seedlings except when applied 7 days preplant. In the latter case, root galling was suppressed to very low numbers. In behavior studies on water agar, Meloidogyne second-stage juveniles were attracted to areas with an increasing tannic acid gradient. Radopholus similis was repelled from the tannic acid gradient in one of two experiments. There was no effect on H. glycines. The response of M. arenaria second-stage juveniles to different concentrations of tannic acid dissolved in alginate was tested. Movement behavior of the second-stage juveniles were observed at 1,000 and 10,000 mug/ml of tannic acid, but not at 10 and 100 mug/ml.

  14. Virulence of Meloidogyne spp. and Induced Resistance in Grape Rootstocks

    PubMed Central

    McKenry, Michael V.; Anwar, Safdar A.

    2007-01-01

    Harmony grape rootstock displays resistance to several Meloidogyne spp. but that resistance is not durable in commercial vineyard settings. A 2-year experiment in a microplot setting revealed host specificities of two virulent populations of Meloidogyne arenaria and an avirulent population of Meloidogyne incognita. In a subsequent split-root experiment, the avirulent nematode population was demonstrated to induce resistance to the virulent nematode population. To quantify the level of resistance, reproduction of the virulent nematode population was determined 63 days after being challenged by an avirulent nematode population using a range of inoculum densities and timeframes. Induction of resistance became apparent when the virulent nematode population was inoculated 7 days after the avirulent nematode population and increased thereafter. The level of induced resistance increased with increased inoculum levels of the avirulent nematode population. Root systems of perennial crops are commonly fed upon simultaneously by multiple nematode species. These two studies indicate that field populations can become preferentially virulent upon one or multiple rootstocks and that co-inhabiting populations may induce existing resistance mechanisms. In perennial crops, it is common for numerous nematode species besides Meloidogyne spp. to be present, including some that feed without causing apparent damage. PMID:19259475

  15. Response of Some Common Annual Bedding Plants to Three Species of Meloidogyne

    PubMed Central

    McSorley, R.; Frederick, J. J.

    1994-01-01

    Twelve ornamental bedding plant cultivars were grown in soil infested with isolates of Meloidogyne incognita race 1, M. javanica, or M. arenaria race 1 in a series of tests in containers in a growth room. Root galling (0-5 scale) and eggs/plant were evaluated 8-10 weeks after soil infestation and seedling transplantation. Snapdragon, Antirrhinum majus cv. First Ladies, was extensively galled and highly susceptible (mean gall rating ≥4.2 and ≥14,500 eggs/plant), and Celosia argentea cv. Century Mix and Coleus blumei cv. Rainbow were susceptible (>1,500 eggs/plant) to all three Meloidogyne isolates. Response of Petunia x hybrida varied with cultivar and nematode isolate. Little or no galling or egg production from any Meloidogyne isolate was observed on Ageratum houstonianum cv. Blue Mink, Lobularia maritima cv. Rosie O'Day, or Tagetes patula cv. Dwarf Primrose. Galling was slight (mean rating ≤2.0) but varied with nematode species on Dianthus chinensis cv. Baby Doll Mix, Salvia splendens cv. Bonfire, and Vinca rosea cv. Little Bright Eye. Verbena × hybrida cv. Florist was heavily infected (gall rating >4.0 and ≥7,900 eggs/plant) by M. javanica and M. arenaria but was nearly free of galling from M. incognita. Zinna elegans cv. Scarlet was nearly free of galling from M. incognita and M. arenaria but was susceptible (mean gall rating = 2.9; 3,400 eggs/plant) to M. javanica. PMID:19279963

  16. Response of some common annual bedding plants to three species of meloidogyne.

    PubMed

    McSorley, R; Frederick, J J

    1994-12-01

    Twelve ornamental bedding plant cultivars were grown in soil infested with isolates of Meloidogyne incognita race 1, M. javanica, or M. arenaria race 1 in a series of tests in containers in a growth room. Root galling (0-5 scale) and eggs/plant were evaluated 8-10 weeks after soil infestation and seedling transplantation. Snapdragon, Antirrhinum majus cv. First Ladies, was extensively galled and highly susceptible (mean gall rating >/=4.2 and >/=14,500 eggs/plant), and Celosia argentea cv. Century Mix and Coleus blumei cv. Rainbow were susceptible (>1,500 eggs/plant) to all three Meloidogyne isolates. Response of Petunia x hybrida varied with cultivar and nematode isolate. Little or no galling or egg production from any Meloidogyne isolate was observed on Ageratum houstonianum cv. Blue Mink, Lobularia maritima cv. Rosie O'Day, or Tagetes patula cv. Dwarf Primrose. Galling was slight (mean rating 4.0 and >/=7,900 eggs/plant) by M. javanica and M. arenaria but was nearly free of galling from M. incognita. Zinna elegans cv. Scarlet was nearly free of galling from M. incognita and M. arenaria but was susceptible (mean gall rating = 2.9; 3,400 eggs/plant) to M. javanica.

  17. Histopathological response of Lens culinaris roots towards root-knot nematode, Meloidogyne incognito.

    PubMed

    Singh, Swarn; Abbasi; Hisamuddin

    2013-04-01

    Lens culinaris (lentil) is an important pulse crop. The yield of the crop is reduced if grown in root-knot nematode (Meloidogyne incognita) infested field. Meloidogyne incognita caused infection in primary and the secondary roots leading to the anomalies in the affected part of the root. The study revealed that the second stage juveniles (J2) of Meloidogyne incognita entered the growing roots and their branches inter and intracellularly. The immediate response was hypertrophy and hyperplasia in the root tissue near the nematode head. In response to hypertrophy some cells became very large and contained dense and granular cytoplasm. Adjacent to the giant cells, the vascular tissue was found to be disturbed. Shape, size and orientation of the vascular elements was so much altered that it had become difficult to trace the normal course of vascular strands. In various sections vascular strands were found disrupted. The vessel elements had the shapes resembling the shapes of parenchyma cells. Similarly sieve tube elements of the phloem, near the giant cells were shorter and resembled with nearby parenchyma cells. Abnormalities in xylem and phloem favored transport water, minerals and metabolites towards the giant cells. From this study, it might be inferred that alteration in the cells of galled tissue was essential for the sustenance of giant cells and for the survival of the nematode.

  18. Nematicidal activity of furanocoumarins from parsley against Meloidogyne spp.

    PubMed

    Caboni, Pierluigi; Saba, Marco; Oplos, Chrisostomos; Aissani, Nadhem; Maxia, Andrea; Menkissoglu-Spiroudi, Urania; Casu, Laura; Ntalli, Nikoletta

    2015-08-01

    This report describes activity against Meloidogyne spp. and chemical characterisation of the essential oil and methanol extract of Petroselinum crispum aerial parts. The study was based on the hypothesis that P. crispum could be used as an intercrop and soil amendment in tomato culture for nematode control. The methanol extract and the essential oil exhibited significant nematicidal activity against M. incognita, M. hapla and M. arenaria, the first being the most sensitive species, with EC50 /72 h values of 140 ± 15 and 795 ± 125 mg L(-1) for the extract and oil respectively. The most abundant furanocoumarin compounds in the methanolic extract were xanthotoxin, psoralen, bergapten and oxypeucedanin; levels ranged from 1.77 to 46.04 mg kg(-1) wet weight. The EC50 /24 h values of xanthotoxol, psoralen and xanthotoxin against M. incognita were 68 ± 33, 147 ± 88 and 200 ± 21 mg L(-1) respectively. The addition of fresh parsley paste to soil reduced the number of M. incognita females and plant galls on tomato roots; EC50 values were 24.79 and 28.07 mg g(-1) respectively. Moreover, parsley paste enhanced tomato growth in a dose-response manner. Parsley exhibits promising nematicidal activity as an organic amendment and as a source of nematotoxic furanocoumarins. © 2014 Society of Chemical Industry.

  19. Phylogenetic Analyses of Meloidogyne Small Subunit rDNA

    PubMed Central

    De Ley, Irma Tandingan; De Ley, Paul; Vierstraete, Andy; Karssen, Gerrit; Moens, Maurice; Vanfleteren, Jacques

    2002-01-01

    Phylogenies were inferred from nearly complete small subunit (SSU) 18S rDNA sequences of 12 species of Meloidogyne and 4 outgroup taxa (Globodera pallida, Nacobbus abberans, Subanguina radicicola, and Zygotylenchus guevarai). Alignments were generated manually from a secondary structure model, and computationally using ClustalX and Treealign. Trees were constructed using distance, parsimony, and likelihood algorithms in PAUP* 4.0b4a. Obtained tree topologies were stable across algorithms and alignments, supporting 3 clades: clade I = [M. incognita (M. javanica, M. arenaria)]; clade II = M. duytsi and M. maritima in an unresolved trichotomy with (M. hapla, M. microtyla); and clade III = (M. exigua (M. graminicola, M. chitwoodi)). Monophyly of [(clade I, clade II) clade III] was given maximal bootstrap support (mbs). M. artiellia was always a sister taxon to this joint clade, while M. ichinohei was consistently placed with mbs as a basal taxon within the genus. Affinities with the outgroup taxa remain unclear, although G. pallida and S. radicicola were never placed as closest relatives of Meloidogyne. Our results show that SSU sequence data are useful in addressing deeper phylogeny within Meloidogyne, and that both M. ichinohei and M. artiellia are credible outgroups for phylogenetic analysis of speciations among the major species. PMID:19265950

  20. Enhanced Synthesis of Antioxidant Enzymes, Defense Proteins and Leghemoglobin in Rhizobium-Free Cowpea Roots after Challenging with Meloydogine incognita

    PubMed Central

    Oliveira, Jose T. A.; Araujo-Filho, Jose H.; Grangeiro, Thalles B.; Gondim, Darcy M. F.; Segalin, Jeferson; Pinto, Paulo M.; Carlini, Celia R. R. S.; Silva, Fredy D. A.; Lobo, Marina D. P.; Costa, Jose H.; Vasconcelos, Ilka M.

    2014-01-01

    The root knot nematodes (RKN), Meloydogine spp., particularly Meloidogyne incognita and Meloidogyne javanica species, parasitize several plant species and are responsible for large annual yield losses all over the world. Only a few available chemical nematicides are still authorized for RKN control owing to environmental and health reasons. Thus, plant resistance is currently considered the method of choice for controlling RKN, and research performed on the molecular interactions between plants and nematodes to identify genes of interest is of paramount importance. The present work aimed to identify the differential accumulation of root proteins of a resistant cowpea genotype (CE-31) inoculated with M. incognita (Race 3) in comparison with mock-inoculated control, using 2D electrophoresis assay, mass spectrometry identification and gene expression analyses by RT-PCR. The results showed that at least 22 proteins were differentially represented in response to RKN challenge of cowpea roots mainly within 4–6 days after inoculation. Amongst the up-represented proteins were SOD, APX, PR-1, β-1,3-glucanase, chitinases, cysteine protease, secondary metabolism enzymes, key enzymes involved in ethylene biosynthesis, proteins involved in MAPK pathway signaling and, surprisingly, leghemoglobin in non-rhizobium-bacterized cowpea. These findings show that an important rearrangement in the resistant cowpea root proteome occurred following challenge with M. incognita. PMID:28250394

  1. Bahiagrass for the Management of Meloidogyne arenaria in Peanut

    PubMed Central

    Rodríguez-Kábana, R.; Weaver, C. F.; Robertson, D. G.; Ivey, H.

    1988-01-01

    Bahiagrass (Paspalum notatum) cultivars Argentine, Pensacola, and Tifton-9 were non-hosts for Meloidogyne arenaria, M. incognita, and Heterodera glycines in a greenhouse experiment using field soil infested with these nematodes. The effect of Pensacola bahiagrass in rotation with peanut (Arachis hypogaea) on M. arenaria was studied in 1986 and 1987 in a field at the Wiregrass substation near Headland, Alabama. Each year soil densities of second-stage juveniles of M. arenaria, determined near peanut harvest, were 96-98% lower under bahiagrass than under peanut. In 1987 peanut yields in plots following bahiagrass were 27% higher than in plots under peanut monoculture. Juvenile population densities in bahiagrass-peanut plots were 41% lower than in plots with continuous peanut. Using bahiagrass for reducing population densities of M. arenaria and increasing peanut yield was as effective as using aldicarb at the recommended rates for peanut. PMID:19290315

  2. Reproductive Variability of Field Populations of Meloidogyne spp. on Grape Rootstocks

    PubMed Central

    Anwar, Safdar A.; McKenry, M. V.; Faddoul, J.

    2000-01-01

    Variability in penetration, development, and reproduction of two resistance-breaking field pathotypes (pt.) of Meloidogyne arenaria, M. incognita, and a population of mixed Meloidogyne spp. virulent to grape hosts were compared on two resistant Vitis rootstocks 'Freedom' and 'Harmony' in separate tests. 'Cabernet Sauvignon' was included as a susceptible host to all four nematode populations. Secondstage juveniles (J2) of the mixed population failed to penetrate Freedom roots. By contrast, 6% of J2 in the M. incognita population penetrated Freedom roots but did not develop beyond the swollen J2 stage. The two resistance-breaking populations of M. arenaria differed in their virulence except on susceptible roots of Cabernet Sauvignon. More J2 of M. arenaria pt. Freedom penetrated Freedom roots and reached adult stage than did M. arenaria pt. Harmony. Later life stages of M. arenaria pt. Freedom occurred earlier and in greater numbers in Harmony roots than did M. arenaria pt. Harmony. Reproduction of M. arenaria pt. Freedom was greater in Freedom and Harmony roots than M. arenaria pt. Harmony. Thus, one population of M. arenaria is highly virulent and the other is moderately virulent. PMID:19270976

  3. Mentha x piperita, Mentha spicata and Effects of Their Essential Oils on Meloidogyne in Soil.

    PubMed

    Walker, J T; Melin, J B

    1996-12-01

    Six peppermint (Mentha x piperita) and six spearmint (M. spicata) PI accessions were inoculated with Meloidogyne incognita race 3 and M. arenaria race 2, under greenhouse conditions. No galls formed on roots of any of the plants inoculated with 1,800 eggs/pot. Fewer than two galls per root system formed on three PI accessions of peppermint inoculated with M. incognita at 5,400 eggs/pot. Only one peppermint accession developed galls when inoculated with M. arenaria, whereas none of the spearmint accessions was susceptible to this species. Plant dry weights generally were unaffected by infection with root-knot nematodes at these densities. Growing peppermint and spearmint accessions for 8 or 12 weeks in M. arenaria-infested soil before tomato resulted in 90% reduction of root galls compared with tomato following tomato. Cineole, eugenol, geraniol, linalool, and peppermint oils at 50 and 250 mg oil/kg soil caused no reduction in the number of galls caused by M. arenaria on tomato. At 1,500 mg oil/kg soil, geraniol, eugenol, linalool, and peppermint oils (P =0.05) reduced the number of galls caused by M. arenaria, but the decrease in galling caused by M. incognita was not significant. Geraniol, linalool, and peppermint oil at 1,000 and 1,500 mg were phytotoxic to tomato.

  4. Mentha x piperita, Mentha spicata and Effects of Their Essential Oils on Meloidogyne in Soil

    PubMed Central

    Walker, J. T.; Melin, J. B.

    1996-01-01

    Six peppermint (Mentha x piperita) and six spearmint (M. spicata) PI accessions were inoculated with Meloidogyne incognita race 3 and M. arenaria race 2, under greenhouse conditions. No galls formed on roots of any of the plants inoculated with 1,800 eggs/pot. Fewer than two galls per root system formed on three PI accessions of peppermint inoculated with M. incognita at 5,400 eggs/pot. Only one peppermint accession developed galls when inoculated with M. arenaria, whereas none of the spearmint accessions was susceptible to this species. Plant dry weights generally were unaffected by infection with root-knot nematodes at these densities. Growing peppermint and spearmint accessions for 8 or 12 weeks in M. arenaria-infested soil before tomato resulted in 90% reduction of root galls compared with tomato following tomato. Cineole, eugenol, geraniol, linalool, and peppermint oils at 50 and 250 mg oil/kg soil caused no reduction in the number of galls caused by M. arenaria on tomato. At 1,500 mg oil/kg soil, geraniol, eugenol, linalool, and peppermint oils (P =0.05) reduced the number of galls caused by M. arenaria, but the decrease in galling caused by M. incognita was not significant. Geraniol, linalool, and peppermint oil at 1,000 and 1,500 mg were phytotoxic to tomato. PMID:19277186

  5. Evaluation of Cover Crops with Potential for Use in Anaerobic Soil Disinfestation (ASD) for Susceptibility to Three Species of Meloidogyne.

    PubMed

    Kokalis-Burelle, Nancy; Butler, David M; Rosskopf, Erin N

    2013-12-01

    Several cover crops with potential for use in tropical and subtropical regions were assessed for susceptibility to three common species of root-knot nematode, Meloidogyne arenaria, M. incognita, and M. javanica. Crops were selected based on potential use as organic amendments in anaerobic soil disinfestation (ASD) applications. Nematode juvenile (J2) numbers in soil and roots, egg production, and host plant root galling were evaluated on arugula (Eruca sativa, cv. Nemat), cowpea (Vigna unguiculata, cv. Iron & Clay), jack bean (Canavalia ensiformis, cv. Comum), two commercial mixtures of Indian mustard and white mustard (Brassica juncea & Sinapis alba, mixtures Caliente 61 and Caliente 99), pearl millet (Pennisetum glaucum, cv. Tifleaf III), sorghum-sudangrass hybrid (Sorghum bicolor × S. bicolor var. sudanense, cv. Sugar Grazer II), and three cultivars of sunflower (Helianthus annuus, cvs. 545A, Nusun 660CL, and Nusun 5672). Tomato (Solanum lycopersicum, cv. Rutgers) was included in all trials as a susceptible host to all three nematode species. The majority of cover crops tested were less susceptible than tomato to M. arenaria, with the exception of jack bean. Sunflower cv. Nusun 5672 had fewer M. arenaria J2 isolated from roots than the other sunflower cultivars, less galling than tomato, and fewer eggs than tomato and sunflower cv. 545A. Several cover crops did not support high populations of M. incognita in roots or exhibit significant galling, although high numbers of M. incognita J2 were isolated from the soil. Arugula, cowpea, and mustard mixture Caliente 99 did not support M. incognita in soil or roots. Jack bean and all three cultivars of sunflower were highly susceptible to M. javanica, and all sunflower cultivars had high numbers of eggs isolated from roots. Sunflower, jack bean, and both mustard mixtures exhibited significant galling in response to M. javanica. Arugula, cowpea, and sorghum-sudangrass consistently had low numbers of all three

  6. Isolation and characterization of another cDNA encoding a chorismate mutase from the phytoparasitic nematode Meloidogyne arenaria.

    PubMed

    Long, Hai; Wang, Xuan; Xu, Jian Hua; Hu, Yong Jian

    2006-06-01

    A new cDNA, named Ma-cm-2, encoding a chorismate mutase (CM), has been isolated from Meloidogyne arenaria. The full-length cDNA, carrying the trans-spliced SL1 leader sequence, was 753-bp long with an open reading frame of 576 bp. The deduced protein MA-CM-2 including amino-terminal signal peptide shows significant similarity to CMs of Meloidogyne incognita, Meloidogyne javanica, and also bacteria. Secondary structure prediction of MA-CM-2 indicates the presence of the three conserved alpha-helix domains present in the Escherichia coli CMs. Reverse transcription and polymerase chain reaction analysis showed that its transcript abundance is high in the early developmental stages and low in later ones. In situ mRNA hybridization revealed that the transcripts of Ma-cm-2 accumulated specifically in the two subventral oesophageal gland cells of M. arenaria. The widespread existence of CMs in the sedentary endoparasitic nematodes implicates that this enzyme plays an important role in the host-parasite interaction.

  7. Crop Rotation Studies with Velvetbean (Mucuna deeringiana) for the Management of Meloidogyne spp.

    PubMed Central

    Rodríguez-Kábana, R.; Pinochet, J.; Robertson, D. G.; Wells, L.

    1992-01-01

    Results from a greenhouse experiment at Cabrils, Spain, with two velvetbean (Mucuna deeringiana) accessions (Florida and Mozambique) growing in sterilized sandy loam and inoculated with Meloidogyne arenaria race 2, M. incognita race 1, and M. javanica revealed that the legume was not a host for these nematodes. In contrast, roots of 'Clemson Spineless' okra (Hibiscus esculentum), 'Summer Crookneck' squash (Cucurbita pepo), and 'Davis' soybean (Glycine max) were galled by all three root-knot nematodes. Greenhouse experiments at Auburn, Alabama, using soils infested with Heterodera glycines (race 14) + M. incognita or with H. glycines + M. arenaria (race 2) showed that, in contrast to Davis soybean, a Mexican and the Florida velvetbean accessions were not hosts for the nematodes. An experiment with 'Florunner' peanut (Arachis hypogaea) and the Florida velvetbean in a field infested with M. arenaria (race 1), near Headland, Alabama, showed that significant juvenile populations of the nematode at peanut harvest time were present only in plots with peanut. A microplot rotation experiment demonstrated that 'Black Beauty' eggplant (Solanum melongena) following the Florida velvetbean had heavier shoots and lower numbers of M. arenaria juveniles in the roots and in the soil than eggplant after Summer Crookneck squash or Davis soybean. PMID:19283043

  8. Variability of Meloidogyne exigua on Coffee in the Zona da Mata of Minas Gerais State, Brazil

    PubMed Central

    Oliveira, D. S.; Oliveira, R. D. L.; Freitas, L. G.; Silva, R. V.

    2005-01-01

    Minas Gerais is the major coffee-producing state of Brazil, with 28% of its production coming from the region of Zona da Mata. Four major species of root-knot nematode attacking coffee (Meloidogyne incognita, M. paranaensis, M. coffeicola, and M. exigua) have been reported from Brazil. To determine the variability in Meloidogyne spp. occurring in that region, 57 populations from 20 localities were evaluated for morphological, enzymatic, and physiological characteristics. According to the perineal pattern, all the populations were identified as M. exigua; however populations from the municipality of São João do Manhuaçu exhibited patterns very similar to M. arenaria. The identity of all the populations was confirmed by the phenotypes of esterase, malate dehydrogenase, superoxide dismutase, and glutamate-oxaloacetate transaminase. Thirteen populations (22.8%) showed the typical one-band (E1) esterase phenotype, whereas the others (77.2%) had a novel two-band phenotype (E2). No intraspecies variability was found in any population. All populations were able to reproduce on tomato, pepper, beans, cacao, and soybean. Reproduction was greater on tomato and pepper than on coffee seedlings, the susceptible standard. PMID:19262880

  9. Alternate row placement is ineffective for cultural control of Meloidogyne incognita in cotton

    USDA-ARS?s Scientific Manuscript database

    The objective of this study was to determine if planting cotton into the space between the previous year's rows reduces crop loss due to nematodes compared to planting in the same row every year. Row placement had a significant (P = 0.05) effect on nematode counts only on 8 July 2005. Plots receiv...

  10. Genetic diversity, virulence, and Meloidogyne incognita interactions of Fusarium oxysporum isolates causing cotton wilt in Georgia

    USDA-ARS?s Scientific Manuscript database

    Locally severe outbreaks of Fusarium wilt of cotton (Gossypium spp.) in South Georgia raised concerns about the genotypes of the causal pathogen, Fusarium oxysporum f. sp. vasinfectum. Vegetative complementation tests and DNA sequence analysis were used to determine genetic diversity among 492 F. ox...

  11. Dose response of soilborne plant pathogens and Meloidogyne incognita to citrus-based experimental compounds.

    USDA-ARS?s Scientific Manuscript database

    Two novel citrus-based compounds have been tested in vitro against Colletotrichum gleosporioides, Fusarium oxysporum, Sclerotinia sclerotiorum, Sclerotium rolfsii, Rhizoctonia solani, Verticillium albo-atrum, Pythium aphanidermatum, P. myriotilum, Phytophthora nicotianae and P. capsici. One of the...

  12. Purification and characterization of chitinases from Paecilomyces variotii DG-3 parasitizing on Meloidogyne incognita eggs.

    PubMed

    Nguyen, Van-Nam; Oh, In-Jae; Kim, Young-Ju; Kim, Kil-Yong; Kim, Young-Cheol; Park, Ro-Dong

    2009-02-01

    Two extracellular chitinases were purified from Paecilomyces variotii DG-3, a chitinase producer and a nematode egg-parasitic fungus, to homogeneity by DEAE Sephadex A-50 and Sephadex G-100 chromatography. The purified enzymes were a monomer with an apparent molecular mass of 32 kDa (Chi32) and 46 kDa (Chi46), respectively, and showed chitinase activity bands with 0.01% glycol chitin as a substrate after SDS-PAGE. The first 20 and 15 N-terminal amino acid sequences of Chi32 and Chi46 were determined to be Asp-Pro-Typ-Gln-Thr-Asn-Val-Val-Tyr-Thr-Gly-Gln-Asp-Phe-Val-Ser-Pro-Asp-Leu-Phe and Asp-Ala-X-X-Tyr-Arg-Ser-Val-Ala-Tyr-Phe-Val-Asn-Trp-Ala, respectively. Optimal temperature and pH of the Chi32 and Chi46 were found to be both 60 degrees C, and 2.5 and 3.0, respectively. Chi32 was almost inhibited by metal ions Ag(+) and Hg(2+) while Chi46 by Hg(2+) and Pb(2+) at a 10 mM concentration but both enzymes were enhanced by 1 mM concentration of Co(2+). On analyzing the hydrolyzates of chitin oligomers [(GlcNAc)( n ), n = 2-6)], it was considered that Chi32 degraded chitin oligomers as an exo-type chitinase while Chi46 as an endo-type chitinase.

  13. Greenhouse evaluation of capsicum rootstocks for management of meloidogyne incognita on grafted bell pepper

    USDA-ARS?s Scientific Manuscript database

    The growth, development, and nematode susceptibility of various rootstock genotypes grafted to a commercial bell pepper variety scion were evaluated in a series of greenhouse experiments. Nine rootstocks including ‘Caribbean Red Habanero’, ‘ PA-136’ , ‘Keystone Resistant Giant’, ‘Yolo Wonder’, ‘Car...

  14. Expression of a Cystatin Transgene in Eggplant Provides Resistance to Root-knot Nematode, Meloidogyne incognita

    PubMed Central

    Papolu, Pradeep K.; Dutta, Tushar K.; Tyagi, Nidhi; Urwin, Peter E.; Lilley, Catherine J.; Rao, Uma

    2016-01-01

    Root-knot nematodes (RKN) cause substantial yield decline in eggplant and sustainable management options to minimize crop damage due to nematodes are still limited. A number of genetic engineering strategies have been developed to disrupt the successful plant–nematode interactions. Among them, delivery of proteinase inhibitors from the plant to perturb nematode development and reproduction is arguably the most effective strategy. In the present study, transgenic eggplant expressing a modified rice cystatin (OC-IΔD86) gene under the control of the root-specific promoter, TUB-1, was generated to evaluate the genetically modified nematode resistance. Five putative transformants were selected through PCR and genomic Southern blot analysis. Expression of the cystatin transgene was confirmed in all the events using western blotting, ELISA and qPCR assay. Upon challenge inoculation, all the transgenic events exhibited a detrimental effect on RKN development and reproduction. The best transgenic line (a single copy event) showed 78.3% inhibition in reproductive success of RKN. Our results suggest that cystatins can play an important role for improving nematode resistance in eggplant and their deployment in gene pyramiding strategies with other proteinase inhibitors could ultimately enhance crop yield. PMID:27516765

  15. Effect of Meloidogyne incognita parasitism on yield and sugar content of sugar beet in Georgia

    USDA-ARS?s Scientific Manuscript database

    Sugar beet (Beta vulgaris) is typically grown as a summer crop for edible sugar production in the north-central and western US, but it could be incorporated as a winter crop into annual cropping systems in the southern US where the sugar would be used for biofuel and plastic production. Sugar beet ...

  16. Sex Differentiation in Meloidogyne incognita and Anatomical Evidence of Sex Reversal

    PubMed Central

    Papadopoulou, Joanna; Traintaphyllou, A. C.

    1982-01-01

    Sex differentiation was studied by examining the cellular structure of gonad primordia extracted from second-stage juveniles developing under different environmental conditions. In female jnveniles, divisions of the two somatic cells of the primordium occurred in mid-sccond stage and resulted in 12 cells. Two of them were differentiated as cap cells, two occupied the anterior central and eight the posterior central part of the V-shaped primordium. The two germinal cells divided at the 6-8 somatic-cell stage of the primordium; i.e., earlier than in any other plant-parasitic nematode. In male juveniles of similar developmental stage, divisions of somatic cells resulted in 10 cells: one cap cell at the posterior tip and nine cells at the anterior part of the rod-shaped primordium. Germinal cells divided at the 6-8 sontatic-cell stage. On the basis of gonad anatomy it was concluded that some female juveniles undergo sex reversal and proceed with further development as males. The degree of expression of intersexual features depends on the period at which sex reversal occurs. Sex reversal at an early period gives rise to males with one testis, almost indistinguishable front true males. Sex reversal at mid-second stage involves degeneration of the nucleus of one of the cap cells resulting in males with an atrophied testis and a well-developed testis. More delayed sex reversal results in males with two testes of approximately equal size. To explain these patterns of development, it is assumed that sex differentiation is hormonally controlled and that the environment influences hormonal balance by affecting gene expression. PMID:19295752

  17. Effects of metabolites of Gliocladium Roseum on egg hatch and juvenile mortality of Meloidogyne incognita

    USDA-ARS?s Scientific Manuscript database

    Root-knot disease caused by root-knot nematode is a serious yield limiting factor for several economically important crops including soybean, vegetables, fruit trees, tea, tobacco, and medicinal plants. Control of nematode is currently mostly limited to application of soil nematicides, which are cos...

  18. Utility of Grafting for Managing Southern Root-knot Nematode, Meloidogyne Incognita, in Watermelon

    USDA-ARS?s Scientific Manuscript database

    Four bottlegourd (Lagenaria siceraria) cultivars, one squash (Cucurbita moschata x C. maxima) hybrid, four wild watermelon (Citrullus lanatus var. citroides) germplasm lines, and one commercial wild watermelon (C. lanatus var. citroides) cultivar were evaluated as rootstocks for cultivated watermelo...

  19. Grafting for Management of Southern Root-knot Nematode, Meloidogyne Incognita, in Watermelon

    USDA-ARS?s Scientific Manuscript database

    Four bottlegourd (Lagenaria siceraria) cultivars, one squash (Cucurbita moschata x C. maxima) hybrid, four wild watermelon (Citrullus lanatus var. citroides) germplasm lines, and one commercial wild watermelon (C. lanatus var. citroides) cultivar were evaluated as rootstocks for cultivated watermelo...

  20. Biocontrol Efficacy Among Strains of Pochonia chlamydosporia Obtained from a Root-Knot Nematode Suppressive Soil

    PubMed Central

    Yang, Jiue-in; Loffredo, Angelo; Borneman, James; Becker, J. Ole

    2012-01-01

    Three Pochonia chlamydosporia var. chlamydosporia strains were isolated from a Meloidogyne incognita-suppressive soil, and then genetically characterized with multiple Pochonia-selective typing methods based on analysis of ß-tubulin, rRNA internal transcribed spacer (ITS), rRNA small subunit (SSU), and enterobacterial repetitive intergenic consensus (ERIC) PCR. All strains exhibited different patterns with the ERIC analysis. Strains 1 and 4 were similar with PCR analysis of ß-tubulin and ITS. The strains' potential as biological control agents against root-knot nematodes were examined in greenhouse trials. All three P. chlamydosporia strains significantly reduced the numbers of nematode egg masses. When chlamydospores were used as inoculum, strain 4 reduced egg numbers on tomato roots by almost 50%, and showed effects on the numbers of J2 and on nematode-caused root-galling. A newly developed SSU-based PCR analysis differentiated strain 4 from the others, and could therefore potentially be used as a screening tool for identifying other effective biocontrol strains of P. chlamydosporia var. chlamydosporia. PMID:23483846

  1. An early record of Meloidogyne fallax from Ireland

    PubMed Central

    Topalović, Olivera; Moore, John F.; Janssen, Toon; Bert, Wim; Karssen, Gerrit

    2017-01-01

    Abstract Root-knot nematodes, Meloidogyne spp., cause huge economic losses worldwide. Currently, three Meloidogyne spp. are present on the quarantine A2 list of EPPO, Meloidogyne chitwoodi, Meloidogyne fallax and Meloidogyne enterolobii. As a quarantine organism, Meloidogyne fallax has been detected in England and Northern Ireland on sport turf in 2011, and in England on leek in 2013. However, its presence in Ireland has probably been overlooked since 1965, when Mr. John F. Moore and Dr. Mary T. Franklin had detected a new Meloidogyne species for that time. While the relevant data was recorded and a preliminary manuscript describing the species was prepared but never submitted for publication, and together with the original slides, pictures and drawings, it was restudied recently. We compared the population of Irish Meloidogyne sp. to other similar Meloidogyne spp. Careful observation and comparison shows that it belongs to Meloidogyne fallax. The characters found to be common for Irish Meloidogyne sp. and Meloidogyne fallax are female stylet length (14.6 μm) with oval to rounded basal knobs, oval shaped perineal pattern with moderately high dorsal arch, slender stylet in males (18.5 μm) with set off and rounded basal knobs, slightly set off male head with one post-labial annule and incomplete transverse incisures, and second-stage juveniles with large and rounded stylet basal knobs, and a gradually tapering tail (46.9 μm) with a broadly rounded tip and a clearly delimitated smooth hyaline part sometimes marked by constrictions (12.9 μm). The host test and gall formation also correspond to Meloidogyne fallax. The identification could not be additionally supported by molecular analysis, as we were unable to extract DNA from the old permanent slides. Nevertheless, our study reveals that the Meloidogyne species detected in Ireland in 1965 belongs to Meloidogyne fallax. PMID:28144174

  2. Reproduction of Belonolaimus longicaudatus, Meloidogyne javanica, Paratrichodorus minor, and Pratylenchus brachyurus on Pearl Millet (Pennisetum glaucum)

    PubMed Central

    Timper, P.; Hanna, W. W.

    2005-01-01

    Pearl millet (Pennisetum glaucum) has potential as a grain crop for dryland crop production in the southeastern United States. Whether or not pearl millet will be compatible in rotation with cotton (Gossypium hirsutum), corn (Zea mays), and peanut (Arachis hypogaea) will depend, in part, on its host status for important plant-parasitic nematodes of these crops. The pearl millet hybrid 'TifGrain 102' is resistant to both Meloidogyne incognita race 3 and M. arenaria race 1; however, its host status for other plant-parasitic nematodes was unknown. In this study, the reproduction of Belonolaimus longicaudatus, Paratrichodorus minor, Pratylenchus brachyurus, and Meloidogyne javanica race 3 on pearl millet ('HGM-100' and TifGrain 102) was compared relative to cotton, corn, and peanut. Separate greenhouse experiments were conducted for each nematode species. Reproduction of B. longicaudatus was lower on peanut and the two millet hybrids than on cotton and corn. Reproduction of P. minor was lower on peanut and TifGrain 102 than on cotton, corn, and HGM-100. Reproduction of P. brachyurus was lower on both millet hybrids than on cotton, corn, and peanut. Reproduction of M. javanica race 3 was greater on peanut than on the two millet hybrids and corn. Cotton was a nonhost. TifGrain 102 was more resistant than HGM-100 to reproduction of B. longicaudatus, P. minor, and M. javanica. Our results demonstrated that TifGrain 102 was a poor host for B. longicaudatus and P. brachyurus (Rf < 1) and, relative to other crops tested, was less likely to increase densities of P. minor and M. javanica. PMID:19262863

  3. Analysis of 1,3-Dichloropropene for Control of Meloidogyne spp. in a Tobacco Pest Management System

    PubMed Central

    Fortnum, B. A.; Johnson, A. W.; Lewis, S. A.

    2001-01-01

    1,3-Dichloropropene (1,3-D) and nonfumigant nematicides were evaluated for control of Meloidogyne spp. and soil and foliar insects in a tobacco pest management system. In a field with a high Meloidogyne spp. population density (root gall index 4.0 to 4.5 on a 0 to 10 scale in untreated controls), tobacco yields and crop values increased (482 kg/ha and $1,784/ha for 1, 3-D; 326 kg/ha and $1,206/ha for fenamiphos; 252 kg/ha and $933/ha for ethoprop) with nematicide application over an untreated control. In fields with a low population density of Meloidogyne arenaria or M. incognita (root gall index 2.3 to 2.5 in untreated controls), yields ranged from 1,714 to 2,027 kg/ha and were not altered by fumigant or nonfumigant nematicide application. Carbofuran, a soil-applied nonfumigant nematicide/insecticide, reduced the number of foliar insecticide applications required to keep insect populations below treatment threshold (3.8 vs. 4.5, respectively, for treated vs. untreated). Carbofuran reduced the cost ($23/ha) of foliar insecticide treatments when compared to an untreated control. Although nonfumigant nematicides provided some soil and foliar insect control, the cost of using a fumigant plus a lower insecticidal rate of a soil insecticide/nematicide was comparable to the least expensive non-fumigant nematicide when the cost of foliar insecticide applications was included in the cost estimates. Savings in foliar insecticide cost by use of soil-applied nonfumigant nematicide/insecticides were small ($23/ha) in comparison to potential value reductions by root-knot nematodes when the nonfumigant nematicides fenamiphos or ethoprop ($578/ha and $851/ha, respectively) were used instead of 1,3-D. PMID:19265897

  4. Morphological and Molecular Evaluation of a Meloidogyne hapla Population Damaging Coffee (Coffea arabica) in Maui, Hawaii

    PubMed Central

    Handoo, Z. A.; Skantar, A. M.; Carta, L. K.; Schmitt, D. P.

    2005-01-01

    An unusual population of Meloidogyne hapla, earlier thought to be an undescribed species, was found causing large galls, without adventitious roots, and substantial damage to coffee in Maui, Hawaii. Only in Brazil had similar damage to coffee been reported by this species. Unlike M. exigua from South and Central America, this population reproduced well on coffee cv. Mokka and M. incognita-susceptible tomato but poorly on tomato with the Mi resistance gene. Characterization included SEM images, esterase isozymes, and five DNA sequences: i) the D3 segment of the large subunit (LSU-D3 or 28S) rDNA, ii) internal transcribed spacer (ITS-1) rDNA, iii) intergenic spacer (IGS) rDNA, iv) the mitochondrial interval from cytochrome oxidase (CO II) to 16S mtDNA, and v) the nuclear gene Hsp90. Sequences for ITS-1, IGS, and COII were similar to other M. hapla populations, but within species ITS-1 variability was not less than among species. One LSU-D3 haplotype was similar to a previously analyzed population with two minor haplotypes. Hsp90 exhibited some variation between Maryland and Hawaiian populations distinct from other species. Females were narrow with wide vulval slits, large interphasmidial distances, and more posterior excretory pores; 20% of perineal patterns had atypical perivulval lines. Males had a low b ratio (<12 µm). Juveniles had a short distance between stylet and dorsal gland orifice. Juvenile body length was short (<355 µm) and was different between summer and winter populations. PMID:19262853

  5. Influence of Photoperiod and Temperature on Migrations of Meloidogyne Juveniles

    PubMed Central

    Prot, Jean-Claude; Van Gundy, S. D.

    1981-01-01

    Photoperiod influences the migration of M. incognita juveniles toward tomato roots. Approximately 33% migrated vertically 20 cm in 7 days to roots when 12 h dark were alternated with 12 h light. Only 7% migrated when light was constant for 24 h. Vertical migration of M. incognita juveniles was studied at 14, 16, 18, 20, and 22 C. The migration of M. incognita juveniles begins at about 18 C and reaches its maximum at 22 C. The migration of M. hapla and M. incognita juveniles were compared at 14, 18, and 22 C. Juveniles of M. hapla were able to migrate at a lower temperature than those of M. incognita. With M. hapla, there was no significant difference in migration between 18 and 22 C. PMID:19300748

  6. The Multi-Resistant Reaction of Drought-Tolerant Coffee 'Conilon Clone 14' to Meloidogyne spp. and Late Hypersensitive-Like Response in Coffea canephora.

    PubMed

    Lima, Edriana A; Furlanetto, Cleber; Nicole, Michel; Gomes, Ana C M M; Almeida, Maria R A; Jorge-Júnior, Aldemiro; Correa, Valdir R; Salgado, Sônia Maria; Ferrão, Maria A G; Carneiro, Regina M D G

    2015-06-01

    Root-knot nematodes (RKN), Meloidogyne spp., have major economic impact on coffee production in Central and South America. Genetic control of RKN constitutes an essential part for integrated pest management strategy. The objective of this study was to evaluate the resistance of Coffea canephora genotypes (clones) to Meloidogyne spp. Sensitive and drought-tolerant coffee genotypes were used to infer their resistance using nematode reproduction factor and histopathology. Eight clonal genotypes were highly resistant to M. paranaensis. 'Clone 14' (drought-tolerant) and 'ESN2010-04' were the only genotypes highly resistant and moderately resistant, respectively, to both M. incognita races 3 and 1. Several clones were highly resistant to both avirulent and virulent M. exigua. Clone 14 and ESN2010-04 showed multiple resistance to major RKNs tested. Roots of 'clone 14' (resistant) and 'clone 22' (susceptible) were histologically studied against infection by M. incognita race 3 and M. paranaensis. Reduction of juvenile (J2) penetration in clone 14 was first seen at 2 to 6 days after inoculation (DAI). Apparent early hypersensitive reaction (HR) was seen in root cortex between 4 and 6 DAI, which led to cell death and prevention of some nematode development. At 12 to 20 DAI, giant cells formed in the vascular cylinder, besides normal development into J3/J4. From 32 to 45 DAI, giant cells were completely degenerated. Late, intense HR and cell death were frequently observed around young females and giant cells reported for the first time in coffee pathosystem. These results provide rational bases for future studies, including prospection, characterization, and expression profiling of genomic loci involved in both drought tolerance and resistance to multiple RKN species.

  7. Tinea Incognita in a Patient with Crest Syndrome: Case Report.

    PubMed

    Gorgievska-Sukarovska, Biljana; Skerlev, Mihael; Žele-Starčević, Lidija

    2015-01-01

    Tinea incognita is a dermatophytic infection that is difficult to diagnose, usually modified by inappropriate topical or systemic corticosteroid therapy. We report an extensive case of tinea incognita caused by the zoophilic dermatophyte Trichophyton mentagrophytes (var. granulosa) in a 49-year-old female patient with CREST (Calcinosis; Raynaud phenomenon; Esophageal involvement; Sclerodactyly; Teleangiectasia) syndrome. Immunocompromised patients, as well as patients with keratinization disorders, seem to be especially susceptible to dermatophytic infections with atypical clinical presentation that is sometimes bizarre and difficult to recognize. Therefore, close monitoring and mycological skin examination is recommended in order to avoid misdiagnosis and to give the patient the best chance of recovery.

  8. Effects of the Mi-1, N and Tabasco Genes on Infection and Reproduction of Meloidogyne mayaguensis on Tomato and Pepper Genotypes

    PubMed Central

    Brito, J. A.; Stanley, J. D.; Kaur, R.; Cetintas, R.; Di Vito, M.; Thies, J. A.; Dickson, D. W.

    2007-01-01

    Meloidogyne mayaguensis is a damaging root-knot nematode able to reproduce on root-knot nematode-resistant tomato and other economically important crops. In a growth chamber experiment conducted at 22 and 33°C, isolate 1 of M. mayaguensis reproduced at both temperatures on the Mi-1-carrying tomato lines BHN 543 and BHN 585, whereas M. incognita race 4 failed to reproduce at 22°C, but reproduced well at 33°C. These results were confirmed in another experiment at 26 ± 1.8°C, where minimal or no reproduction of M. incognita race 4 was observed on the Mi-1-carrying tomato genotypes BHN 543, BHN 585, BHN 586 and ‘Sanibel’, whereas heavy infection and reproduction of M. mayaguensis isolate 1 occurred on these four genotypes. Seven additional Florida M. mayaguensis isolates also reproduced on resistant ‘Sanibel’ tomato at 26 ± 1.8°C. Isolate 3 was the most virulent, with reproduction factor (Rf) equal to 8.4, and isolate 8 was the least virulent (Rf = 2.1). At 24°C, isolate 1 of M. mayaguensis also reproduced well (Rf ≥ 1) and induced numerous small galls and large egg masses on the roots of root-knot nematode-resistant bell pepper ‘Charleston Belle’ carrying the N gene and on three root-knot nematode-resistant sweet pepper lines (9913/2, SAIS 97.9001 and SAIS 97.9008) carrying the Tabasco gene. In contrast, M. incognita race 4 failed to reproduce or reproduced poorly on these resistant pepper genotypes. The ability of M. mayaguensis isolates to overcome the resistance of tomato and pepper genotypes carrying the Mi-1, N and Tabasco genes limits the use of resistant cultivars to manage this nematode species in infested tomato and pepper fields in Florida. PMID:19259507

  9. Effects of the Mi-1, N and Tabasco Genes on Infection and Reproduction of Meloidogyne mayaguensis on Tomato and Pepper Genotypes.

    PubMed

    Brito, J A; Stanley, J D; Kaur, R; Cetintas, R; Di Vito, M; Thies, J A; Dickson, D W

    2007-12-01

    Meloidogyne mayaguensis is a damaging root-knot nematode able to reproduce on root-knot nematode-resistant tomato and other economically important crops. In a growth chamber experiment conducted at 22 and 33 degrees C, isolate 1 of M. mayaguensis reproduced at both temperatures on the Mi-1-carrying tomato lines BHN 543 and BHN 585, whereas M. incognita race 4 failed to reproduce at 22 degrees C, but reproduced well at 33 degrees C. These results were confirmed in another experiment at 26 +/- 1.8 degrees C, where minimal or no reproduction of M. incognita race 4 was observed on the Mi-1-carrying tomato genotypes BHN 543, BHN 585, BHN 586 and 'Sanibel', whereas heavy infection and reproduction of M. mayaguensis isolate 1 occurred on these four genotypes. Seven additional Florida M. mayaguensis isolates also reproduced on resistant 'Sanibel' tomato at 26 +/- 1.8 degrees C. Isolate 3 was the most virulent, with reproduction factor (Rf) equal to 8.4, and isolate 8 was the least virulent (Rf = 2.1). At 24 degrees C, isolate 1 of M. mayaguensis also reproduced well (Rf >/= 1) and induced numerous small galls and large egg masses on the roots of root-knot nematode-resistant bell pepper 'Charleston Belle' carrying the N gene and on three root-knot nematode-resistant sweet pepper lines (9913/2, SAIS 97.9001 and SAIS 97.9008) carrying the Tabasco gene. In contrast, M. incognita race 4 failed to reproduce or reproduced poorly on these resistant pepper genotypes. The ability of M. mayaguensis isolates to overcome the resistance of tomato and pepper genotypes carrying the Mi-1, N and Tabasco genes limits the use of resistant cultivars to manage this nematode species in infested tomato and pepper fields in Florida.

  10. Descriptions of Meloidogyne camelliae n.sp. and M. querciana n.sp (Nematoda:Meloidogynidae), with SEM and Host-Range Observations.

    PubMed

    Golden, A M

    1979-04-01

    Meloidogyne camelliae n.sp. on camellia (Camellia japonica) from Japan and M. querciana n.sp. on pin oak (Quercus palustris) from Virginia, USA, are described and illustrated. M. camelliae n.sp. is distingnishable from other species of the genus especially by its striking perineal pattern having heavy ropelike striae forming a squarish to rectangular outline with shoulders or projections, appearing sometimes ahnost starlike. M. querciana differs from other species by its characteristic perineal pattern round to oval in outline, sometimes with a low arch, and sunken vulva surrounded by a prominent obovate area devoid of striae. M. querciana shows some relationship to M. ovalis, but differs further fxom the latter by longer larvae, absence of annules on head of larvae, and rarity of males. Examination of specimens of M. camelliae n.sp. and M. querciana n.sp. with the scanning electron microscope confirmed observations made by optical microscopy and revealed diagnostic and other structures in greater detail. In greenhouse host tests, M. camelliae infected camellia heavily, showed moderate infection on oxalis, only a trace infection on tomato, and no infection on five other plants tested; and M. querciana attacked pin oak, red oak, and American chestnut heavily, but did not infect nine other test plants. In another test, pin oak seedlings did not become infected when heavily inoculated with and grown in the presence of two populations of M. incognita incognita and one of M. incognita acrita. The common names "camellia root-knot nematode" and "oak root-knot nematode" are respectively proposed for M. camelliae and M. querciana.

  11. Descriptions of Meloidogyne camelliae n.sp. and M. querciana n.sp (Nematoda:Meloidogynidae), with SEM and Host-Range Observations

    PubMed Central

    Golden, A. Morgan

    1979-01-01

    Meloidogyne camelliae n.sp. on camellia (Camellia japonica) from Japan and M. querciana n.sp. on pin oak (Quercus palustris) from Virginia, USA, are described and illustrated. M. camelliae n.sp. is distingnishable from other species of the genus especially by its striking perineal pattern having heavy ropelike striae forming a squarish to rectangular outline with shoulders or projections, appearing sometimes ahnost starlike. M. querciana differs from other species by its characteristic perineal pattern round to oval in outline, sometimes with a low arch, and sunken vulva surrounded by a prominent obovate area devoid of striae. M. querciana shows some relationship to M. ovalis, but differs further fxom the latter by longer larvae, absence of annules on head of larvae, and rarity of males. Examination of specimens of M. camelliae n.sp. and M. querciana n.sp. with the scanning electron microscope confirmed observations made by optical microscopy and revealed diagnostic and other structures in greater detail. In greenhouse host tests, M. camelliae infected camellia heavily, showed moderate infection on oxalis, only a trace infection on tomato, and no infection on five other plants tested; and M. querciana attacked pin oak, red oak, and American chestnut heavily, but did not infect nine other test plants. In another test, pin oak seedlings did not become infected when heavily inoculated with and grown in the presence of two populations of M. incognita incognita and one of M. incognita acrita. The common names "camellia root-knot nematode" and "oak root-knot nematode" are respectively proposed for M. camelliae and M. querciana. PMID:19305554

  12. Effects of Chicken-excrement Amendments on Meloidogyne arenaria

    PubMed Central

    Kaplan, M.; Noe, J. P.

    1993-01-01

    The effects of chicken litter on Meloidogyne arenaria in tomato plants cv. Rutgers were determined in the greenhouse. Tomato seedlings were transplanted into a sandy soil amended with five rates of chicken litter and inoculated with 2,000 M. arenaria eggs. After 10 days, total numbers of nematodes in the roots decreased with increasing rates of chicken litter. After 46 days, egg numbers also decreased with increasing litter rates. In another experiment, soil was amended with two litter types, N-P-K fertilizer, and the two primary constituents of chicken litter (manure and pine-shaving bedding). After 10 days, numbers of nematodes in roots were smaller in chicken-excrement treatments as compared to nonexcrement treatments. At 46 days, there were fewer nematode eggs in chicken-excrement treatments compared to nonexcrement treatments. Egg numbers also were smaller for fertilizer and pine-shaving amendments as compared to nonamended controls. Chicken litter and manure amendments suppressed plant growth by 10 days after inoculation but enhanced root weights at 46 days after inoculation. Amendment of soil with chicken litter suppressed M. arenaria and may provide practical control of root-knot nematodes as part of an integrated management system. PMID:19279745

  13. The use of root gall ratings to determine high risk zones in cotton fields infested by Meloidogyne Incognita

    USDA-ARS?s Scientific Manuscript database

    Cotton farmers need a reliable, accurate, and inexpensive method for determining the potential threat of root-knot nematodes (RKN) to cotton within individual fields for site specific application of nematicides. Evaluation of cotton roots for RKN galling at harvest may be an alternative to soil ana...

  14. Precision mapping and identification of candidate genes for a QTL affecting Meloidogyne incognita reproduction in Upland cotton

    USDA-ARS?s Scientific Manuscript database

    The resistant line Auburn 623RNR and a number of elite breeding lines derived from it remain the most important source of root-knot nematode (RKN) resistance because they exhibit the highest level of resistance to RKN known to date in Upland cotton (Gossypium hirsutum L). Prior genetic mapping analy...

  15. Greenhouse Evaluation of a commercial Bell Pepper scion grafted onto various Capsicum rootstocks for management of Meloidogyne incognita.

    USDA-ARS?s Scientific Manuscript database

    The growth, development, and nematode susceptibility of various rootstock genotypes grafted to a commercial bell pepper variety scion were evaluated in conventional and climate controlled greenhouses. Eight rootstocks including ‘Caribbean Red Habanero’, ‘PA-136’, ‘Keystone Resistant Giant’, ‘Yolo W...

  16. Effects of catechins and low temperature on embryonic development and hatching in Heterodera glycines and Meloidogyne incognita

    USDA-ARS?s Scientific Manuscript database

    Mimics of two natural influences, a chemical similar to one present in cyst nematodes and low temperature exposure of nematode eggs, were evaluated for their effects on quantitative and qualitative features of embryonic development and hatching. The polyphenol epigallocatechin gallate (EGCG), an ana...

  17. Nematotoxicity of drupacine and a Cephalotaxus alkaloid preparation against the plant-parasitic nematodes Meloidogyne incognita and Bursaphelenchus xylophilus

    USDA-ARS?s Scientific Manuscript database

    Species of Cephalotaxus (the plum yews) produce nematotoxic compounds of unknown identity. Consequently, bioassay-guided fractionation was employed to identify the compound(s) in Cephalotaxus fortunei twigs and leaves with activity against plant-parasitic nematodes. A crude alkaloid extract, particu...

  18. Behaviour of Heterodera glycines and Meloidogyne incognita infective juveniles exposed to nematode FMRFamide-like peptides in vitro

    USDA-ARS?s Scientific Manuscript database

    Plant-parasitic nematodes depend upon a family of neuropeptides, the FMRFamide-like peptides (FLPs), to regulate locomotion and behavior. To exploit FLPs as leads to novel nematode control agents, an understanding of how specific FLPs affect behavior, and what differences exist between species, is i...

  19. Meloidogyne javanica on Peanut in Florida

    PubMed Central

    Cetintas, R.; Lima, R. D.; Mendes, M. L.; Brito, J. A.; Dickson, D. W.

    2003-01-01

    A mixed population of Meloidogyne arenaria race 1 and M. javanica race 3 is reported on peanut from a field in Levy County, Florida. Confirmation of M. javanica on peanut is based on esterase and malate dehydrogenase isozyme patterns resolved on polyacrylamide slab gels following electrophoresis, and perineal patterns. Up to 29% of 290 individual females collected from peanut roots in the field in autumn 2002 showed a typical esterase J3 phenotype for M. javanica. This is the third report of M. javanica infecting peanut in the United States. PMID:19262776

  20. Temporal efficacy of selected nematicides on meloidogyne species on tobacco.

    PubMed

    Melton, T A; Barker, K R; Koenning, S R; Powell, N T

    1995-09-01

    Aldicarb, ethoprop, and fenamiphos were evaluated for their efficacy in controlling various species of root-knot nematodes on flue-cured tobacco and for their residual activity, as determined through periodic sampling and bioassays of soil taken from field plots. Field experiments were conducted at five locations over 2 years with flue-cured tobacco. Soil in plots treated with nematicides were formed into high, wide beds before transplanting with 'Coker 371-Gold' or 'K 326' tobacco. Residual control of Meloidogyne spp. was greatest (P Suppression of nematode reproduction by ethoprop was short-lived, and numbers of second-stage juveniles + eggs and numbers of galls in bioassays sometimes surpassed those of untreated plots within 4 weeks after treatment. Aldicarb gave intermediate control over time as compared to the other compounds. Although nematicidal efficacy of all compounds varied with site and season, fenamiphos and aldicarb generally produced the highest yields.

  1. Tinea Incognita following the Use of an Antipsoriatic Gel

    PubMed Central

    Starace, Michela; Alessandrini, Aurora; Piraccini, Bianca Maria

    2016-01-01

    Tinea incognita is a dermatophyte infection of the skin whose clinical presentation has been modified by the misuse of steroids or, as has been described recently, calcineurin inhibitors. We report a case of pustular psoriasis treated with an antipsoriatic cream, composed of topical steroids and a vitamin D3 derivative, which gave rise to a tinea incognita. Our case underlines that clinical features of fungal infection can be modified by the increasing use of self-prescribed topical therapies, usually applied to treat incorrectly ‘self-diagnosed’ diseases. Moreover, we suggest that a mycological examination should be performed in every atypical presentation of skin lesion, and to rule out tinea pedis, in any disease of the feet that requires topical application of steroids. PMID:27171394

  2. Meloidogyne paranaensis n. sp. (Nemata: Meloidogynidae), a Root-Knot Nematode Parasitizing Coffee in Brazil

    PubMed Central

    Carneiro, R. M. D. G.; Carneiro, R. G.; Abrantes, I. M. O.; Santos, M. S. N. A.; Almeida, M. R. A.

    1996-01-01

    A root-knot nematode parasitizing coffee in Paran  State, Brazil, is described as Meloidogyne paranaensis n. sp. The suggested common name is Paraná coffee root-knot nematode. The perineal pattern is similar to that of M. incognita; the labial disc and medial lips of the female are fused and asymmetric and rectangular; the lateral lips are small, triangular, and fused laterally with the head region. The female stylet is 15.0-17.5 μm long, with broad, distinctly set-off knobs; the distance from the dorsal esophageal gland orifice (DGO) to the stylet base is 4.2-5.5 μm. Males have a high, round head cap continuous with the body contour. The labial disc is fused with the medial lips to form an elongate lip structure. The head region is frequently marked by an incomplete annulation. The stylet is robust, 20-27 μm long, usually with round to transversely elongate knobs, sometimes with one or two projections protruding from the shaft. The stylet length of second-stage juveniles is 13-14 μm, the distance of the DGO to the stylet base is 4.0-4.5 μm, and the tail length is 48-51 μm. Biochemically, the esterase (F₁) and malate dehydrogenase (N₁) phenotypes are the most useful characters to differentiate M. paranaensis from other species. However, the esterase phenotype appears similar to that of M. konaensis. Reproduction is by mitotic parthenogenesis, 3n = 50-52. In differential host tests, tobacco, watermelon, and tomato were good hosts, whereas cotton, pepper, and peanut were nonhosts. PMID:19277133

  3. Greenhouse Evaluation of Selected Soybean Germplasm for Resistance to North Carolina Populations of Heterodera glycines, Rotylenchulus reniformis, and Meloidogyne Species

    PubMed Central

    Davis, E. L.; Koenning, S. R.; Burton, J. W.; Barker, K. R.

    1996-01-01

    Selected soybean genotypes were evaluated for resistance to North Carolina populations of the soybean cyst nematode Heterodera glycines, the root-knot nematodes Meloidogyne incognita races 3 and 4, M. arenaria races 1 and 2, M. javanica, and the reniform nematode Rotylenchulus reniformis in two greenhouse tests. Populations of cyst nematode used in the first test were cultures from field samples originally classified as races 1-5, and those used in the second test included inbred cyst lines that corresponded to races 1, 3, and 4. The original race classification of some cyst populations shifted after repeated culture on susceptible 'Lee 68' soybean. Most of the cyst-resistant soybean cultivars tested were susceptible to M. arenaria and M. javanica. Exceptionally large galls were induced by M. arenaria on roots of Asgrow 5979, Hartwig, and CNS soybean. Hartwig soybean and PI 437654 were resistant to all cultured field populations of cyst nematodes in a first greenhouse test. In the second test, cyst indices of 11.3% and 19.4% were observed on roots of PI 437654 and Hartwig, respectively, when infected with an inbred line (OP50) of H. glycines corresponding to race 4. The cyst-resistant soybean germplasm tested, including Hartwig and PI 437654, supported only low numbers of reniform nematodes. The most severe soybean root necrosis observed, however, was associated with reniform nematode infection. PMID:19277179

  4. Molecular Characterisation and Diagnosis of Root-Knot Nematodes (Meloidogyne spp.) from Turfgrasses in North Carolina, USA

    PubMed Central

    Ye, Weimin; Zeng, Yongsan; Kerns, James

    2015-01-01

    Root-knot nematodes (Meloidogyne spp.) are the most common and destructive plant-parasitic nematode group worldwide and adversely influence both crop quality and yield. In this study, a total of 51 root-knot nematode populations from turfgrasses were tested, of which 44 were from North Carolina, 6 from South Carolina and 1 from Virginia. Molecular characterisation was performed on these samples by DNA sequencing on the ribosomal DNA 18S, ITS and 28S D2/D3. Species-specific primers were developed to identify turfgrass root-knot nematode through simplex or duplex PCR. Four species were identified, including M. marylandi Jepson & Golden in Jepson, 1987, M. graminis (Sledge & Golden, 1964) Whitehead, 1968, M. incognita (Kofoid & White, 1919) Chitwood, 1949 and M. naasi Franklin, 1965 through a combined analysis of DNA sequencing and PCR by species-specific primers. M. marylandi has been reported from North Carolina and South Carolina for the first time. Molecular diagnosis using PCR by species-specific primers provides a rapid and cheap species identification approach for turfgrass root-knot nematodes. PMID:26599462

  5. Evaluation of six common peach rootstocks to Meloidogyne mayaguensis

    USDA-ARS?s Scientific Manuscript database

    Flordaguard, Guardian, Halford, Lovell, Nemaguard, and Okinawa peach rootstocks were evaluated for their susceptibility to Meloidogyne mayaguensis in two separate experiments. All rootstocks were rated as poor hosts of M. mayaguensis. Evaluating different peach rootstocks for resistance to M. ma...

  6. Meloidogyne polycephannulata n. sp. (Nematoda: Meloidogynidae), a root-knot nematode parasitizing carrot in Brazil

    PubMed Central

    Charchar, João M.; Vieira, Jairo V.; Fonseca-Boiteux, Maria Esther de N.; Boiteux, Leonardo S.

    2009-01-01

    ) at Rm 52; M. petuniae has two SB at Rm 44 and 53; M. phaseoli has a SB at 53, 58, and 64 Rm; M. brasilensis has three SB at Rm 40, 58, and 66 and a WB at Rm 71; M. pisi has a SB at Rm 40, 60, and 64 and two WB at 46 and 50 Rm. Data from sequencing the 18S rDNA region of M. polycephannulata n. sp. confirms that it is different from M. arabicida, M. arenaria, M. ethiopica, M. incognita, M. javanica, M. paranaensis, and M. thailandica. Sequence identity among these eight species ranged between 85 to 93.4%. Meloidogyne polycephannulata n. sp. reproduces very well on carrot and tomato; poorly on pepper; and not at all on cotton, peanut, tobacco, watermelon, and sweet corn. PMID:22736812

  7. Parasitism of Woody Ornamentals by Meloidogyne hapla

    PubMed Central

    Bernard, E. C.; Witte, W. T.

    1987-01-01

    Meloidogyne hapla is the dominant root-knot nematode found in Tennessee woody ornamental nurseries. In greenhouse tests, M. hapla produced galls and formed egg masses on roots of Abelia x grandiflora, Comus florida, Hydrangea paniculata grandiflora, Photinia x fraseri, Spiraea x bumalda, Spiraea x vanhouttei, and Viburnum carlesii. Galls on H. grandiflora and V. carlesii were mostly large and fusiform. Galls on C. florida were spherical and usually terminal, whereas those on the other species were minute. Lateral roots grew from galls on all susceptible plants. Two Acer spp., two Buxus spp., three llex spp., five Prunus spp., three Rhododendron spp., Euonymus alata, Ligustrum sinense, Magnolia x soulangiana, Nandina domestica, and nine conifer species were nonhosts or very poor hosts. PMID:19290273

  8. Mixtures of Olive Pomace with Different Nitrogen Sources for the Control of Meloidogyne spp. on Tomato

    PubMed Central

    Rodríguez-Kábana, R.; Estaún, V.; Pinochet, J.; Marfá, O.

    1995-01-01

    The efficacy of mixtures of dry olive (Olea europea) pomace with biuret, guanidine, and melamine for control of root-knot nematodes (Meloidogyne spp.) on tomato (Lycopersicon esculentum) was studied in greenhouse experiments. Olive pomace (OP) applied pre-plant at 10 g/kg soil was phytotoxic. Mixtures of OP (10 g/kg soil) with biuret or guanidine at 200-300 mg/kg soil reduced or eliminated the phytotoxic effect, controlled root-knot nematodes, and increased soil esterase activity indicative of microbial activity. The addition of biuret or guanidine without OP to soil at rates <300 mg/kg soil did not control root-knot nematodes. Melamine applied at 100-400 mg/kg soil was phytotoxic as were mixtures of melamine with OP. Treatment of OP with anhydrous ammonia increased N content of the material. In another greenhouse experiment, NH₃-treated OP added to soil was not phytotoxic to tomato, suppressed root-knot nematodes, and increased soil esterase activity. Greenhouse and microplot experiments with OP plus chicken litter demonstrated the efficacy of these combination amendments to control root-knot nematodes and increase tomato yields in Meloidogyne-infested soil. PMID:19277325

  9. Interaction of Concurrent Populations of Meloidogyne partityla and Mesocriconema xenoplax on Pecan.

    PubMed

    Nyczepir, A P; Wood, B W

    2008-09-01

    The effect of the interaction between Meloidogyne partityla and Mesocriconema xenoplax on nematode reproduction and vegetative growth of Carya illinoinensis 'Desirable' pecan was studied in field microplots. Meloidogyne partityla suppressed reproduction of M. xenoplax, whereas the presence of M. xenoplax did not affect the population density of M. partityla second-stage juveniles in soil. Above-ground tree growth, as measured by trunk diameter 32 months following inoculation, was reduced in the presence of M. partityla alone or in combination with M. xenoplax as compared with the uninoculated control trees. The interaction between M. partityla and M. xenoplax was significant for dry root weight 37 months after inoculation. Results indicate that the presence of the two nematode species together caused a greater reduction in root growth than M. xenoplax alone, but not when compared to M. partityla alone. Mouse-ear symptom severity in pecan leaves was increased in the presence of M. partityla compared with M. xenoplax and the uninoculated control. Infection with M. partityla increased severity of mouse-ear symptoms expressed by foliage. The greater negative impact of M. partityla on vegetative growth of pecan seedlings in field microplots indicates that it is likely a more detrimental pathogen to pecan than is M. xenoplax and is likely an economic pest of pecan.

  10. Interaction of Concurrent Populations of Meloidogyne partityla and Mesocriconema xenoplax on Pecan

    PubMed Central

    Wood, B. W.

    2008-01-01

    The effect of the interaction between Meloidogyne partityla and Mesocriconema xenoplax on nematode reproduction and vegetative growth of Carya illinoinensis ‘Desirable’ pecan was studied in field microplots. Meloidogyne partityla suppressed reproduction of M. xenoplax, whereas the presence of M. xenoplax did not affect the population density of M. partityla second-stage juveniles in soil. Above-ground tree growth, as measured by trunk diameter 32 months following inoculation, was reduced in the presence of M. partityla alone or in combination with M. xenoplax as compared with the uninoculated control trees. The interaction between M. partityla and M. xenoplax was significant for dry root weight 37 months after inoculation. Results indicate that the presence of the two nematode species together caused a greater reduction in root growth than M. xenoplax alone, but not when compared to M. partityla alone. Mouse-ear symptom severity in pecan leaves was increased in the presence of M. partityla compared with M. xenoplax and the uninoculated control. Infection with M. partityla increased severity of mouse-ear symptoms expressed by foliage. The greater negative impact of M. partityla on vegetative growth of pecan seedlings in field microplots indicates that it is likely a more detrimental pathogen to pecan than is M. xenoplax and is likely an economic pest of pecan. PMID:19440263

  11. Effects of Incorporation Method of Ethoprop and Addition of Aldicarb on Potato Tuber Infection by Meloidogyne hapla

    PubMed Central

    Ingham, Russell E.; Morris, Mark; Newcomb, Gene B.

    1991-01-01

    The efficacy of controlling Meloidogyne hapla on potato with water incorporation of ethoprop was compared to physical incorporation before planting. The standard practice of aldicarb application for insect control was also evaluated for M. hapla suppression with and without ethoprop. Physical incorporation before planting by rototilling or discing reduced (P ≤ 0.05) tuber infection. Postplant water incorporation of ethoprop was not as effective as physical incorporation of ethoprop or postplant water incorporation of aldicarb and did not reduce (P ≤ 0.05) tuber infection at harvest. Ethoprop did not affect yield, whereas aldicarb increased yield in one experiment. PMID:19283186

  12. Metabolism of alpha-terpineol by Pseudomonas incognita.

    PubMed

    Madyastha, K M; Renganathan, V

    1984-12-01

    Details of the metabolism of alpha-terpineol by Pseudomonas incognita are presented. Degradation of alpha-terpineol by this organism resulted in the formation of a number of acidic and neutral metabolites. Among the acidic metabolites, beta-isopropyl pimelic acid, 1-hydroxy-4-isopropenyl-cyclohexane-1-carboxylic acid, 8-hydroxycumic acid, oleuropeic acid, cumic acid, and p-isopropenyl benzoic acid have been identified. Neutral metabolites identified were limonene, p-cymene-8-ol, 2-hydroxycineole, and uroterpenol. Cell-free extracts prepared from alpha-terpineol adapted cells were shown to convert alpha-terpineol, p-cymene-8-ol, and limonene to oleuropeic acid, 8-hydroxycumic acid, and perillic acid, respectively, in the presence of NADH. The same cell-free extract contained NAD+ -specific dehydrogenase(s) which converted oleuropyl alcohol, p-cymene-7,8-diol, and perillyl alcohol to their corresponding 7-carboxy acids. On the basis of various metabolites isolated from the culture medium, together with the supporting evidence obtained from enzymatic and growth studies, it appears that P. incognita degrades alpha-terpineol by at least three different routes. While one of the pathways seems to operate via oleuropeic acid, a second may be initiated through the aromatization of alpha-terpineol. The third pathway may involve the formation of limonene from alpha-terpineol and its further metabolism.

  13. A major gene mapped on chromosome XII is the main factor of a quantitatively inherited resistance to Meloidogyne fallax in Solanum sparsipilum.

    PubMed

    Kouassi, Abou Bakari; Bakari, Kouassi Abou; Kerlan, Marie-Claire; Marie-Claire, Kerlan; Caromel, Bernard; Bernard, Caromel; Dantec, Jean-Paul; Jean-Paul, Dantec; Fouville, Didier; Didier, Fouville; Manzanares-Dauleux, Maria; Maria, Manzanares-Dauleux; Ellissèche, Daniel; Daniel, Ellissèche; Mugniéry, Didier; Didier, Mugniéry

    2006-02-01

    Meloidogyne fallax is an emerging pest in Europe and represents a threat for potato production. We report the mapping of genetic factors controlling a quantitative resistance against M. fallax identified in the Solanum sparsipilum genotype 88S.329.15. When infected, this genotype develops a necrotic reaction at the feeding site of the juveniles and totally prevents their development to the female stage. A "F1" diploid progeny consisting of 128 individuals was obtained using the potato (S. tuberosum) dihaploid genotype BF15 H1 as female progenitor. Sixty-eight hybrid genotypes displayed necrosis at the feeding site of the juveniles and 60 other genotypes showed no defence reaction. This suggested a monogenic control of the resistance. However, when considering the number of nematode females developed in their roots, a continuous distribution was observed for both "necrotic" and "non-necrotic" hybrid genotypes, indicating a polygenic control of the resistance. A linkage map of each parental genotype was constructed using AFLP markers. The necrotic reaction (NR) was mapped as a qualitative trait on chromosome XII of the resistant genotype 88S.329.15. Quantitative trait locus (QTL) analysis for the number of nematode females developed per "F1" plant genotype was performed using the QTL cartographer software. No QTL was detected on the linkage map of the susceptible parent. A QTL explaining 94.5% of the phenotypic variation was mapped on chromosome XII of the resistant progenitor. This QTL, named MfaXIIspl, was mapped in a genomic region collinear to the map position of the Mi-3 gene conferring resistance to Meloidogyne incognita in tomato. It corresponds to the NR locus.

  14. The map-1 gene family in root-knot nematodes, Meloidogyne spp.: a set of taxonomically restricted genes specific to clonal species.

    PubMed

    Tomalova, Iva; Iachia, Cathy; Mulet, Karine; Castagnone-Sereno, Philippe

    2012-01-01

    Taxonomically restricted genes (TRGs), i.e., genes that are restricted to a limited subset of phylogenetically related organisms, may be important in adaptation. In parasitic organisms, TRG-encoded proteins are possible determinants of the specificity of host-parasite interactions. In the root-knot nematode (RKN) Meloidogyne incognita, the map-1 gene family encodes expansin-like proteins that are secreted into plant tissues during parasitism, thought to act as effectors to promote successful root infection. MAP-1 proteins exhibit a modular architecture, with variable number and arrangement of 58 and 13-aa domains in their central part. Here, we address the evolutionary origins of this gene family using a combination of bioinformatics and molecular biology approaches. Map-1 genes were solely identified in one single member of the phylum Nematoda, i.e., the genus Meloidogyne, and not detected in any other nematode, thus indicating that the map-1 gene family is indeed a TRG family. A phylogenetic analysis of the distribution of map-1 genes in RKNs further showed that these genes are specifically present in species that reproduce by mitotic parthenogenesis, with the exception of M. floridensis, and could not be detected in RKNs reproducing by either meiotic parthenogenesis or amphimixis. These results highlight the divergence between mitotic and meiotic RKN species as a critical transition in the evolutionary history of these parasites. Analysis of the sequence conservation and organization of repeated domains in map-1 genes suggests that gene duplication(s) together with domain loss/duplication have contributed to the evolution of the map-1 family, and that some strong selection mechanism may be acting upon these genes to maintain their functional role(s) in the specificity of the plant-RKN interactions.

  15. Reproduction of Meloidogyne chitwoodi on Popcorn Cultivars

    PubMed Central

    Cardwell, D. M.; Ingham, R. E.

    1997-01-01

    Popcorn cultivars were evaluated in field and greenhouse tests for resistance to the Columbia root-knot nematode, Meloidogyne chitwoodi, as potential resistant crops in potato rotations. A nematode reproductive factor (Rf) was calculated for each cultivar. Reproductive factor values also were compared on a relative basis as percentages of the Rf on a susceptible field corn standard, Pioneer 3578. Popcorn cultivars W206 and Robust 33-77 consistently supported low population densities of M. chitwoodi in repeated tests. However, WOC 9508 had the greatest resistance in any of the field tests, with an Rf value of 0.04. Cultivars with a mean field and greenhouse Rf value less than 50% of the value for Pioneer 3578 were WOC 9508 (8%), WOC 9554 (13%), W206 (15%), WOX 9512 (23%), Robust 33-77 (30%), Robust 20-70 (38%), WOC 9510 (41%), and WOC 9504 (42%). If these cultivars were used in rotation, M. chitwoodi population densities at the end of the popcorn season would be between 58% and 92% less than if Pioneer 3578 were grown. In greenhouse tests, WOX 9511, WOX 9528, WOC 9556, and WOX 9531 also had low Rf values (7-46% that of Pioneer 3578), but field testing of these cultivars is needed. PMID:19274265

  16. A novel effector protein, MJ-NULG1a, targeted to giant cell nuclei plays a role in Meloidogyne javanica parasitism.

    PubMed

    Lin, Borong; Zhuo, Kan; Wu, Ping; Cui, Ruqiang; Zhang, Lian-Hui; Liao, Jinling

    2013-01-01

    Secretory effector proteins expressed within the esophageal glands of root-knot nematodes (Meloidogyne spp.) are thought to play key roles in nematode invasion of host roots and in formation of feeding sites necessary for nematodes to complete their life cycle. In this study, a novel effector protein gene designated as Mj-nulg1a, which is expressed specifically within the dorsal gland of Meloidogyne javanica, was isolated through suppression subtractive hybridization. Southern blotting and BLAST search analyses showed that Mj-nulg1a is unique for Meloidogyne spp. A real-time reverse-transcriptase polymerase chain reaction assay showed that expression of Mj-nulg1a was upregulated in parasitic second-stage juveniles and declined in later parasitic stages. MJ-NULG1a contains two putative nuclear localization signals and, consistently, in planta immunolocalization analysis showed that MJ-NULG1a was localized in the nuclei of giant cells during nematode parasitism. In planta RNA interference targeting Mj-nulg1a suppressed the expression of Mj-nulg1a in nematodes and attenuated parasitism ability of M. javanica. In contrast, transgenic Arabidopsis expressing Mj-nulg1a became more susceptible to M. javanica infection than wild-type control plants. These results depict a novel nematode effector that is targeted to giant cell nuclei and plays a critical role in M. javanica parasitism.

  17. Host status of selected peach rootstocks to Meloidogyne mayaguensis

    USDA-ARS?s Scientific Manuscript database

    Flordaguard, Guardian, Halford, Lovell, Nemaguard, and Okinawa peach rootstocks were evaluated for their susceptibility to Meloidogyne mayaguensis in the greenhouse. All rootstocks were rated as poor hosts of M. mayaguensis. Lovell generally supported greater numbers of M. mayaguensis eggs per pla...

  18. Variability and the recognition of two races in Meloidogyne graminicola

    USDA-ARS?s Scientific Manuscript database

    The rice root-knot nematode, Meloidogyne graminicola, is an important pathogen, impacting rice, wheat and possibly vegetable production in South-East Asia. Ten isolates of M. graminicola from broad geographic areas were compared using traditional and molecular methods. Total body length, oesophageal...

  19. Distribution, hosts and identification of Meloidogyne partityla in the USA

    USDA-ARS?s Scientific Manuscript database

    Pecan, Carya illinoensis, is an economically important nut crop and member of the Juglandaceae native to the southern USA. Discovered in South Africa in 1986, Meloidogyne partityla was first found infecting pecan in USA in 1996 and currently occurs in Texas, New Mexico, Georgia, Arizona, Oklahoma a...

  20. The Nematicidal Effect of Camellia Seed Cake on Root-Knot Nematode Meloidogyne javanica of Banana

    PubMed Central

    Yang, Xiujuan; Wang, Xuan; Wang, Kang; Su, Lanxi; Li, Hongmei; Li, Rong; Shen, Qirong

    2015-01-01

    Suppression of root-knot nematodes is crucially important for maintaining the worldwide development of the banana industry. Growing concerns about human and environmental safety have led to the withdrawal of commonly used nematicides and soil fumigants, thus motivating the development of alternative nematode management strategies. In this study, Meloidogyne javanica was isolated, and the nematicidal effect of Camellia seed cake on this pest was investigated. The results showed that in dish experiments, Camellia seed cake extracts under low concentration (2 g/L) showed a strong nematicidal effect. After treatment for 72 h, the eggs of M. javanica were gradually dissolved, and the intestine of the juveniles gradually became indistinct. Nematicidal compounds, including saponins identified by HPLC-ESI-MS and 8 types of volatile compounds identified by GC-MS, exhibited effective nematicidal activities, especially 4-methylphenol. The pot experiments demonstrated that the application of Camellia seed cake suppressed M. javanica, and promoted the banana plant growth. This study explored an effective nematicidal agent for application in soil and revealed its potential mechanism of nematode suppression. PMID:25849382

  1. The nematicidal effect of camellia seed cake on root-knot nematode Meloidogyne javanica of banana.

    PubMed

    Yang, Xiujuan; Wang, Xuan; Wang, Kang; Su, Lanxi; Li, Hongmei; Li, Rong; Shen, Qirong

    2015-01-01

    Suppression of root-knot nematodes is crucially important for maintaining the worldwide development of the banana industry. Growing concerns about human and environmental safety have led to the withdrawal of commonly used nematicides and soil fumigants, thus motivating the development of alternative nematode management strategies. In this study, Meloidogyne javanica was isolated, and the nematicidal effect of Camellia seed cake on this pest was investigated. The results showed that in dish experiments, Camellia seed cake extracts under low concentration (2 g/L) showed a strong nematicidal effect. After treatment for 72 h, the eggs of M. javanica were gradually dissolved, and the intestine of the juveniles gradually became indistinct. Nematicidal compounds, including saponins identified by HPLC-ESI-MS and 8 types of volatile compounds identified by GC-MS, exhibited effective nematicidal activities, especially 4-methylphenol. The pot experiments demonstrated that the application of Camellia seed cake suppressed M. javanica, and promoted the banana plant growth. This study explored an effective nematicidal agent for application in soil and revealed its potential mechanism of nematode suppression.

  2. RNA interference of effector gene 16D10 leads to broad meloidogyne resistance in potato

    USDA-ARS?s Scientific Manuscript database

    Root-knot nematodes (Meloidogyne spp.) are a significant problem in potato (Solanum tuberosum) production. There is no known Meloidogyne resistance gene in cultivated potato, even though sources of resistance were identified in wild potato species. The objective of this study was to generate stable ...

  3. Rye residue levels affect suppression of the southern root-knot nematode in cotton

    USDA-ARS?s Scientific Manuscript database

    In the southeastern United States, rye (Secale cereale) is frequently planted as a winter cover crop in conservation tillage cotton. Although rye produces toxic benzoxazinoid compounds which may play a role in nematode suppression, it is also a host for the southern root-knot nematode Meloidogyne i...

  4. Mustard seed meal for management of root-knot nematode and weeds in tomato production

    USDA-ARS?s Scientific Manuscript database

    Mustard seed meals of indian mustard [InM (Brassica juncea)] and yellow mustard [YeM (Sinapis alba)], alone and combined, were tested for effects on tomato (Solanum lycopersicum) plants and for suppression of southern root-knot nematode [RKN (Meloidogyne incognita)] and weed populations. In the gree...

  5. Metagenomic insights into communities, functions of endophytes, and their associates with infection by root-knot nematode, Meloidogyne incognita, in tomato roots.

    PubMed

    Tian, Bao-Yu; Cao, Yi; Zhang, Ke-Qin

    2015-11-25

    Endophytes are known to play important roles in plant's health and productivity. In this study, we investigated the root microbiome of tomato in association with infection by root knot nematodes. Our objectives were to observe the effects and response of the bacterial endophytes before nematode attacks and to reveal the functional attributes of microbes in plant health and nematode pathogenesis. Community analysis of root-associated microbiomes in healthy and nematode-infected tomatoes indicated that nematode infections were associated with variation and differentiation of the endophyte and rhizosphere bacterial populations in plant roots. The community of the resident endophytes in tomato root was significantly affected by nemato-pathogenesis. Remarkably, some bacterial groups in the nematode feeding structure, the root gall, were specifically enriched, suggesting an association with nematode pathogenesis. Function-based metagenomic analysis indicated that the enriched bacterial populations in root gall harbored abundant genes related to degradation of plant polysaccharides, carbohydrate and protein metabolism, and biological nitrogen fixation. Our data indicated that some of the previously assumed beneficial endophytes or bacterial associates with nematode might be involved in nematode infections of the tomato roots.

  6. Characterization of a new beta-1,4-endoglucanase gene from the root-knot nematode Meloidogyne incognita and evolutionary scheme for phytonematode family 5 glycosyl hydrolases.

    PubMed

    Ledger, Terence Neil; Jaubert, Stéphanie; Bosselut, Nathalie; Abad, Pierre; Rosso, Marie-Noëlle

    2006-11-01

    Cellulases from plant parasitic nematodes are encoded by multiple gene families and are thought to originate from horizontal gene transfer. Unraveling the evolution of these genes in the phylum will help understanding the evolution of plant parasitism in nematodes. Here we describe a new gene, named MI-eng-2, that encodes a family 5 glycosyl hydrolase (GHF5) with a predicted signal peptide and devoid of linker domain and cellulose-binding domain. The beta-1,4-endoglucanase activity of the protein MI-ENG-2 was confirmed in vitro and the transcription of the gene was localized in the secretory oesophageal glands of infective juveniles, suggesting that MI-ENG-2 is involved in plant cell wall degradation during parasitism. Phylogenetic and exon/intron structure analyses of beta-1,4-endoglucanase genes in the order Tylenchida strengthen the hypothesis that nematode GHF5 genes result from horizontal gene transfer of a bacterial gene with a cellulose-binding domain. GHF5 gene families in Tylenchida result from gene duplications associated with occasional loss of the cellulose-binding domain and the linker domain during their evolution.

  7. Heterodera glycines cysts contain an extensive array of endoproteases as well as inhibitors of proteases in H. glycines and Meloidogyne incognita infective juvenile stages

    USDA-ARS?s Scientific Manuscript database

    Heterodera glycines cysts contain proteases, and inhibitors of protease activities in various nematode species. In this investigation, proteases in H. glycines cysts were identified using a commercially available FRET-peptide library comprising 512 peptide pools qualified to detect up to 4 endoprot...

  8. Metagenomic insights into communities, functions of endophytes, and their associates with infection by root-knot nematode, Meloidogyne incognita, in tomato roots

    PubMed Central

    Tian, Bao-Yu; Cao, Yi; Zhang, Ke-Qin

    2015-01-01

    Endophytes are known to play important roles in plant’s health and productivity. In this study, we investigated the root microbiome of tomato in association with infection by root knot nematodes. Our objectives were to observe the effects and response of the bacterial endophytes before nematode attacks and to reveal the functional attributes of microbes in plant health and nematode pathogenesis. Community analysis of root-associated microbiomes in healthy and nematode-infected tomatoes indicated that nematode infections were associated with variation and differentiation of the endophyte and rhizosphere bacterial populations in plant roots. The community of the resident endophytes in tomato root was significantly affected by nemato-pathogenesis. Remarkably, some bacterial groups in the nematode feeding structure, the root gall, were specifically enriched, suggesting an association with nematode pathogenesis. Function-based metagenomic analysis indicated that the enriched bacterial populations in root gall harbored abundant genes related to degradation of plant polysaccharides, carbohydrate and protein metabolism, and biological nitrogen fixation. Our data indicated that some of the previously assumed beneficial endophytes or bacterial associates with nematode might be involved in nematode infections of the tomato roots. PMID:26603211

  9. Control of Heterodera carotae, Ditylenchus dipsaci, and Meloidogyne javanica with Fumigant and Nonfumigant Nematicides.

    PubMed

    Greco, N; Elia, F; Brandonisio, A

    1986-07-01

    Five field trials were conducted in Italy in 1983 and 1984 to test the efficacy of isazofos and benfuracarb in controlling Heterodera carotae on carrot, Ditylenchus dipsaci on onion, and Meloidogyne javanica on tomato. Methyl isothiocyanate (MIT) was tested against H. carotae and M. javanica. Single (10 kg a.i./ha) and split (5 + 5 kg a.i./ha) applications of isazofos gave yield increases of carrot and onion similar to those obtained with DD (300 liters/ha) and aldicarb (10 kg a.i./ha). Population densities of H. carotae in carrot roots at harvest and of M. javanica in tomato roots 2 months after transplanting were also suppressed by isazofos. Benfuracarb (10 kg a.i./ha increased onion yields in a field infested with D. dipsaci, but it was not effective against H. carotae or M. javanica. The efficacy of MIT at 400 and 600 liters/ha was similar to that of MIT + DD (Di-Trapex) at 300 liters/ha. Both nematicides inhibited hatch of H. carotae eggs and decreased the soil population density of M. javanica.

  10. Effects of Aldicarb on the Behavior of Heterodera schachtii and Meloidogyne javanica

    PubMed Central

    Hough, A.; Thomason, I. J.

    1975-01-01

    The toxic effects of sublethal concentrations ofaldicarb were studied on eggs and second-stage larvae and males of Heterodera schachtii and second-stage larvae only of Meloidogyne javanica in a quartz sand substrate. Aldicarb was more toxic to eggs of H. schachtii than to those of M. javanica. Complete suppression of hatching occurred between 0.48 and 4.8 μg/ml aldicarb for H. schachtii whereas 100% inhibition of hatch of M. javanica occurred between 4.8 and 48.0 μg/ml. M. javanica hatch was stimulated at 0.48 μg/ml aldicarb. Migration of second-stage larvae of H. schachtii and M. javanica in sand columns was inhibited under continuous exposure to 1 μg/ml aldicarb. Infection of sugarbeet and tomato seedlings by larvae was inhibited at 1 μg/ml. H. schachtii males failed to migrate toward nubile females at 0.01 μg/ml aldicarb. This was partially confirmed in a field study in which adding aldicarb to soil resulted in fewer females being fertilized. PMID:19308160

  11. Influence of Temperature and Host Plant on the Interaction Between Pratylenchus neglectus and Meloidogyne chitwoodi

    PubMed Central

    Umesh, Kodira C.; Ferris, Howard

    1994-01-01

    The interaction between Pratylenchus neglectus (Pn) and Meloidogyne chitwoodi (Mc) was investigated at soil temperatures of 15, 20, and 25 C on barley and potato. Maximum numbers of Pn and Mc penetrated barley roots at 20 C, whereas a minimum number penetrated at 15 C. Pratylenchus neglectus restricted root penetration by Mc over time and vice-versa. Population densities of each species increased with increasing temperature. Concomitant inoculation of the two species resulted in lower numbers of Pn at 15 and 25 C in both barley and potato, whereas the numbers of Mc were lower at 15 C in barley and at 25 C in potato. Root weights of potato and barley at 15 and 20 C, respectively, were lowered by the presence of both nematodes singly or concomitantly. At 25 C, barley plants inoculated with Mc alone had lower shoot weight than uninoculated controls, but the damage was restricted when Pn also was present. The two species interact competitively, and the outcome varies with soil temperature and host plant. Pn has the potential to suppress Mc population levels and reduce the damage it causes to potato and barley. PMID:19279870

  12. Effects of Tropical Rotation Crops on Meloidogyne arenaria Population Densities and Vegetable Yields in Microplots.

    PubMed

    McSorley, R; Dickson, D W; de Brito, J A; Hewlett, T E; Frederick, J J

    1994-06-01

    The effects of 12 summer crop rotation treatments on population densities of Meloidogyne arenaria race 1 and on yields of subsequent spring vegetable crops were determined in microplots. The crop sequence was: (i) rotation crops during summer 1991 ; (ii) cover crop of rye (Secale cereale) during winter 1991-92; (iii) squash (Cucurbita pepo) during spring 1992; (iv) rotation crops during summer 1992; (v) rye during winter 1992-93; (vi) eggplant (Solanum melongena) during spring 1993. The 12 rotation treatments were castor (Ricinus communis), cotton (Gossypium hirsutum), velvetbean (Mucuna deeringiana), crotalaria (Crotalaria spectabilis), fallow, hairy indigo (Indigofera hirsuta), American jointvetch (Aeschynomene americana), sorghum-sudangrass (Sorghum bicolor x S. sudanense), soybean (Glycine max), horsebean (Canavalia ensiformis), sesame (Sesamum indicum), and peanut (Arachis hypogaea). Compared to peanut, the first eight rotation treatments resulted in lower (P suppressing nematodes. Yield of squash was greater (P

  13. Effects of Tagetes patula on Active and Inactive Stages of Root-Knot Nematodes

    PubMed Central

    Marahatta, Sharadchandra P.; Wang, Koon-Hui; Sipes, Brent S.; Hooks, Cerruti R. R.

    2012-01-01

    Although marigold (Tagetes patula) is known to produce allelopathic compounds toxic to plant-parasitic nematodes, suppression of Meloidogyne incognita can be inconsistent. Two greenhouse experiments were conducted to test whether marigold is more effective in suppressing Meloidogyne spp. when it is active rather than dormant. Soils infested with Meloidogyne spp. were collected and conditioned in the greenhouse either by 1) keeping the soil dry (DRY), 2) irrigating with water (IRR), or 3) drenching with cucumber (Cucumis sativus) leachate (CL) for 5 wk. These soils were then either planted with cucumber, marigold or remained bare for 10 wk. Suppression of nematode by marigold was then assayed using cucumber. DRY conditioning resulted in the highest number of inactive nematodes, whereas CL and IRR had higher numbers of active nematodes than DRY. At the end of the cucumber bioassay, marigold suppressed the numbers of Meloidogyne females in cucumber roots if the soil was conditioned in IRR or CL, but not in DRY. However, in separate laboratory assays, marigold root leachate slightly reduced M. incognita J2 activity but did not reduce egg hatch (P > 0.05). These finding suggest that marigold can only suppress Meloidogyne spp. when marigold is actively growing. This further suggests that marigold will more efficiently suppress Meloidogyne spp. if planted when these nematodes are in active stage. PMID:23482862

  14. Response of Perennial Herbaceous Ornamentals to Meloidogyne hapla

    PubMed Central

    LaMondia, J. A.

    1995-01-01

    Sixty-nine herbaceous perennial ornamentals in 56 genera were evaluated for root galling after 2 months in soil infested with Meloidogyne hapla under greenhouse conditions. Plants were rated susceptible or resistant based on the number of galls present on the root system. Thirty-six percent had more than 100 galls on the roots (similar to 'Rutgers' tomato controls) and were rated susceptible. Thirty percent of the plants tested did not have galls or egg masses present on the root system and were rated resistant. The remaining 34 percent were intermediate in response. Variation in response to M. hapla was observed within plant genera and species. The identification of M. hapla-resistant perennial ornamentals will aid in management of this nematode in landscapes and production fields. PMID:19277335

  15. Application of mitochondrial DNA polymorphism to meloidogyne molecular population biology.

    PubMed

    Hyman, B C; Whipple, L E

    1996-09-01

    Recent advances in molecular biology have enabled the genotyping of individual nematodes, facilitating the analysis of genetic variability within and among plant-pathogenic nematode isolates. This review first describes representative examples of how RFLP, RAPD, AFLP, and DNA sequence analysis have been employed to describe populations of several phytonematodes, including the pinewood, burrowing, root-knot, and cyst nematodes. The second portion of this paper evaluates the utility of a size-variable mitochondrial DNA locus to examine the genetic structure of Meloidogyne isolates using two alternate methodologies, variable number tandem repeat (VNTR) and repeat associated poiymorphism (RAP) analysis. VNTR analysis has revealed genetic variation among individual nematodes, whereas RAP may provide useful markers for species and population differentiation.

  16. De Novo Analysis of the Transcriptome of Meloidogyne enterolobii to Uncover Potential Target Genes for Biological Control

    PubMed Central

    Li, Xiangyang; Yang, Dan; Niu, Junhai; Zhao, Jianlong; Jian, Heng

    2016-01-01

    Meloidogyne enterolobii is one of the obligate biotrophic root-knot nematodes that has the ability to reproduce on many economically-important crops. We carried out de novo sequencing of the transcriptome of M. enterolobii using Roche GS FLX and obtained 408,663 good quality reads that were assembled into 8193 contigs and 31,860 singletons. We compared the transcripts in different nematodes that were potential targets for biological control. These included the transcripts that putatively coded for CAZymes, kinases, neuropeptide genes and secretory proteins and those that were involved in the RNAi pathway and immune signaling. Typically, 75 non-membrane secretory proteins with signal peptides secreted from esophageal gland cells were identified as putative effectors, three of which were preliminarily examined using a PVX (pGR107)-based high-throughput transient plant expression system in Nicotiana benthamiana (N. benthamiana). Results showed that these candidate proteins suppressed the programmed cell death (PCD) triggered by the pro-apoptosis protein BAX, and one protein also caused necrosis, suggesting that they might suppress plant immune responses to promote pathogenicity. In conclusion, the current study provides comprehensive insight into the transcriptome of M. enterolobii for the first time and lays a foundation for further investigation and biological control strategies. PMID:27598122

  17. Effects of Bahiagrass and Nematicides on Meloidogyne arenaria on Peanut.

    PubMed

    Dickson, D W; Hewlett, T E

    1989-10-01

    A field infested with Meloidogyne arenaria and with a history of peanut yield losses was divided into two equal parts. One-half of the field (bahia site) was planted to bahiagrass in 1986 and maintained through 1987. The other half (peanut site) was planted to soybean in 1986 and peanut in 1987 with hairy vetch planted each fall as a cover crop. In 1988 identical nematicide treatments including 1,3-dichloropropene (1,3-D), aldicarb, and ethoprop were applied to the two sites, and the sites were planted with the peanut cultivar Florunner. At mid-season, population levels of M. arenaria second-stage juveniles in the bahia site were relatively low, compared with those in the peanut site. At harvest, however, population levels were high in both sites. No nematicide treatment increased yields over the untreated control in either site (P

  18. Biology of Meloidogyne platani Hirschmann Parasitic on Sycamore, Platanus occidentalis

    PubMed Central

    Al-Hazmi, A. S.; Sasser, J. N.

    1982-01-01

    The development of Meloidogyne platani on sycamore was followed for 40 days (22-28 C). Juveniles penetrated the feeder roots behind the root cap and invaded the vascular cylinder within 3 days after inoculation. All subsequent development of the nematodes and host effects occurred only within the stele. The second juvenile molt and sex differentiation occurred by the 17th day. Young females were observed by the 26th day. Eggs were observed inside the roots by the 35th day and were exposed to the surface of galls by the 40th day. In pathogenicity studies, a significant negative correlation was shown to exist between fresh shoot and root weights and inoculum density. Besides sycamore, white ash was the only hardwood species tested to become infected. Of the herbacious plants tested, tobacco was heavily galled, tomato and watermelon moderately galled, and pepper only slightly galled. Egg production was moderate on tobacco, slight on tomato and watermelon, and absent on pepper. PMID:19295690

  19. Meloidogyne javanica chorismate mutase 1 alters plant cell development.

    PubMed

    Doyle, Elizabeth A; Lambert, Kris N

    2003-02-01

    Root-knot nematodes are obligate plant parasites that alter plant cell growth and development by inducing the formation of giant cells for feeding. Nematodes inject secretions from their esophageal glands through their stylet and into plant cells to induce giant cell formation. Meloidogyne javanica chorismate mutase 1 (MjCM-1) is one such esophageal gland protein likely to be secreted from the nematode as giant cells form. MjCM-1 has two domains, an N-terminal chorismate mutase (CM) domain and a C-terminal region of unknown function. It is the N-terminal CM domain of the protein that is the predominant form produced in root-knot nematodes. Transgenic expression of MjCM-1 in soybean hairy roots results in a phenotype of reduced and aborted lateral roots. Histological studies demonstrate the absence of vascular tissue in hairy roots expressing MjCM-1. The phenotype of MjCM-1 expressed at low levels can be rescued by the addition of indole-3-acetic acid (IAA), indicating MjCM-1 overexpression reduces IAA biosynthesis. We propose MjCM-1 lowers IAA by causing a competition for chorismate, resulting in an alteration of chorismate-derived metabolites and, ultimately, in plant cell development. Therefore, we hypothesize that MjCM-1 is involved in allowing nematodes to establish a parasitic relationship with the host plant.

  20. Ozone, antioxidant spray and meloidogyne hapla effects on tobacco

    NASA Astrophysics Data System (ADS)

    Bisessar, S.; Palmer, K. T.

    The relationship between ozone and the northern root-knot nematode on tobacco was investigated. Seedlings of tobacco ( Nicotiana tabacum L.) cv. Virginia 115 were inoculated and not inoculated with root-knot ( Meloidogyne hapla (Chitwood) prior to transplanting to a field plot. One-half the plants were sprayed at weekly intervals with an antioxidant, EDU at the rate of 1 kg ha -1 to protect against oxidant injury. O 3 concentrations in excess of 80 ppb were recorded 14 times during the summer of 1982. Ambient ozone inhibited growth and yield of tobacco inoculated and not inoculated with M. hapla. Tobacco inoculated with nematode alone developed significantly more ozone injury than other treatments indicating that tobacco infected with M. hapla is more susceptible to ambient O 3. Significantly 20% more galls developed on plants with nematode inoculation compared to plants with nematode inoculation + EDU indicating that EDU indirectly reduced gall development in tobacco. Plants protected with EDU also showed an increase in dry weight of shoot, root and biomass.

  1. Post-infection Development and Morphology of Meloidogyne cruciani

    PubMed Central

    Garcia-Martinez, R.

    1982-01-01

    The development and life stages of Meloidogyne cruciani on tomato was studied at 28 C. Roots of 2-wk-old 'Rutgers' tomato seedlings were exposed to inoculum for 24 h, rinsed, and the seedlings repotted. No major changes in juvenile development were observed prior to 8 days after inoculation. At 11 days the second-stage juvenile had enlarged considerably. The genital primordium had not yet asumed the V-shape characteristic of developing females, but the presence of rectal glands identified the juveniles as females. At this time (11 days), two additional, previously undescribed esophageal lobes were first observed; they were adjacent to the dorsal and subventral glands. After molting from second to third stage, the stylet cone, shaft, and the lumen of the stylet knobs are shed and remain attached to the second-stage cuticle. The excretory duct of the third-stage juveniles was directed anteriorly from the excretory pore of the second-stage cuticle and appear attached to the body wall of the third-stage juveniles opposite the procorpus. At 19 days after inoculation, the last molt took place. The adult female possessed a new stylet, a large five-gland esophagus, a prominent excretory system ending in a unicellular gland and a fully developed reproductive system. PMID:19295716

  2. Characterization of Soil Suppressiveness to Root-Knot Nematodes in Organic Horticulture in Plastic Greenhouse

    PubMed Central

    Giné, Ariadna; Carrasquilla, Marc; Martínez-Alonso, Maira; Gaju, Núria; Sorribas, Francisco J.

    2016-01-01

    The fluctuation of Meloidogyne population density and the percentage of fungal egg parasitism were determined from July 2011 to July 2013 in two commercial organic vegetable production sites (M10.23 and M10.55) in plastic greenhouses, located in northeastern Spain, in order to know the level of soil suppressiveness. Fungal parasites were identified by molecular methods. In parallel, pot tests characterized the level of soil suppressiveness and the fungal species growing from the eggs. In addition, the egg parasitic ability of 10 fungal isolates per site was also assessed. The genetic profiles of fungal and bacterial populations from M10.23 and M10.55 soils were obtained by Denaturing Gradient Gel Electrophoresis (DGGE), and compared with a non-suppressive soil (M10.33). In M10.23, Meloidogyne population in soil decreased progressively throughout the rotation zucchini, tomato, and radish or spinach. The percentage of egg parasitism was 54.7% in zucchini crop, the only one in which eggs were detected. Pochonia chlamydosporia was the only fungal species isolated. In M10.55, nematode densities peaked at the end of the spring-summer crops (tomato, zucchini, and cucumber), but disease severity was lower than expected (0.2–6.3). The percentage of fungal egg parasitism ranged from 3 to 84.5% in these crops. The results in pot tests confirmed the suppressiveness of the M10.23 and M10.55 soils against Meloidogyne. The number of eggs per plant and the reproduction factor of the population were reduced (P < 0.05) in both non-sterilized soils compared to the sterilized ones after one nematode generation. P. chlamydosporia was the only fungus isolated from Meloidogyne eggs. In in vitro tests, P. chlamydosporia isolates were able to parasitize Meloidogyne eggs from 50 to 97% irrespective of the site. DGGE fingerprints revealed a high diversity in the microbial populations analyzed. Furthermore, both bacterial and fungal genetic patterns differentiated suppressive from non-suppressive

  3. Characterization of Soil Suppressiveness to Root-Knot Nematodes in Organic Horticulture in Plastic Greenhouse.

    PubMed

    Giné, Ariadna; Carrasquilla, Marc; Martínez-Alonso, Maira; Gaju, Núria; Sorribas, Francisco J

    2016-01-01

    The fluctuation of Meloidogyne population density and the percentage of fungal egg parasitism were determined from July 2011 to July 2013 in two commercial organic vegetable production sites (M10.23 and M10.55) in plastic greenhouses, located in northeastern Spain, in order to know the level of soil suppressiveness. Fungal parasites were identified by molecular methods. In parallel, pot tests characterized the level of soil suppressiveness and the fungal species growing from the eggs. In addition, the egg parasitic ability of 10 fungal isolates per site was also assessed. The genetic profiles of fungal and bacterial populations from M10.23 and M10.55 soils were obtained by Denaturing Gradient Gel Electrophoresis (DGGE), and compared with a non-suppressive soil (M10.33). In M10.23, Meloidogyne population in soil decreased progressively throughout the rotation zucchini, tomato, and radish or spinach. The percentage of egg parasitism was 54.7% in zucchini crop, the only one in which eggs were detected. Pochonia chlamydosporia was the only fungal species isolated. In M10.55, nematode densities peaked at the end of the spring-summer crops (tomato, zucchini, and cucumber), but disease severity was lower than expected (0.2-6.3). The percentage of fungal egg parasitism ranged from 3 to 84.5% in these crops. The results in pot tests confirmed the suppressiveness of the M10.23 and M10.55 soils against Meloidogyne. The number of eggs per plant and the reproduction factor of the population were reduced (P < 0.05) in both non-sterilized soils compared to the sterilized ones after one nematode generation. P. chlamydosporia was the only fungus isolated from Meloidogyne eggs. In in vitro tests, P. chlamydosporia isolates were able to parasitize Meloidogyne eggs from 50 to 97% irrespective of the site. DGGE fingerprints revealed a high diversity in the microbial populations analyzed. Furthermore, both bacterial and fungal genetic patterns differentiated suppressive from non-suppressive

  4. Entomopathogenic Nematodes and Bacteria Applications for Control of the Pecan Root-Knot Nematode, Meloidogyne partityla, in the Greenhouse

    PubMed Central

    Shapiro-Ilan, David I.; Nyczepir, Andrew P.; Lewis, Edwin E.

    2006-01-01

    Meloidogyne partityla is a parasite of pecan and walnut. Our objective was to determine interactions between the entomopathogenic nematode-bacterium complex and M. partityla. Specifically, we investigated suppressive effects of Steinernema feltiae (strain SN) and S. riobrave (strain 7–12) applied as infective juveniles and in infected host insects, as well as application of S. feltiae's bacterial symbiont Xenorhabdus bovienii on M. partityla. In two separate greenhouse trials, the treatments were applied to pecan seedlings that were simultaneously infested with M. partityla eggs; controls received only water and M. partityla eggs. Additionally, all treatment applications were re-applied (without M. partityla eggs) two months later. Four months after initial treatment, plants were assessed for number of galls per root system, number of egg masses per root system, number of eggs per root system, number of eggs per egg mass, number of eggs per gram dry root weight, dry shoot weight, and final population density of M. partityla second-stage juveniles (J2). In the first trial, the number of egg masses per plant was lower in the S. riobrave-infected host treatment than in the control (by approximately 18%). In the second trial, dry root weight was higher in the S. feltiae-infected host treatment than in the control (approximately 80% increase). No other treatment effects were detected. The marginal and inconsistent effects observed in our experiments indicate that the treatments we applied are not sufficient for controlling M. partityla. PMID:19259462

  5. Host susceptibility of tall fescue grass to Meloidogyne spp. and Mesocriconema xenoplax

    USDA-ARS?s Scientific Manuscript database

    Preplant fumigant nematicides have traditionally been used to control Meloidogyne spp. and Mesocriconema xenoplax in peach in the Southeast. In recent years growers have faced economic hardships, making it difficult to afford costs associated with these chemicals. Finding an alternative to control...

  6. Maternal stress reduces the susceptibility of Meloidogyne arenaria progeny to Pasteuria penetrans

    USDA-ARS?s Scientific Manuscript database

    Pasteuria penetrans is an obligate parasite of Meloidogyne spp. Endospores of P. penetrans attach to the cuticle of the second-stage juvenile (J2) and the bacterium completes its life cycle in the mature female nematode; infected females are filled with millions of endospores and produce few to no ...

  7. Influence of root exudates and soil on attachment of Pasteuria penetrans to Meloidogyne arenaria

    USDA-ARS?s Scientific Manuscript database

    Pasteuria penetrans is a parasite of root-knot nematodes (Meloidogyne spp.). Endospores of P. penetrans attach to the cuticle of second-stage juveniles (J2) and subsequently sterilize infected females. When encumbered by large numbers of spores, juveniles are less mobile and their ability to infect ...

  8. The interaction between Meloidogyne arenaria and Cylindrocladium parasiticum in runner peanut

    USDA-ARS?s Scientific Manuscript database

    Cylindrocladium black rot (CBR), caused by Cylindrocladium parasiticum, and root-knot nematode, Meloidogyne arenaria, both infect and cause damage to the roots of peanut. Greenhouse and microplot experiments were conducted with the runner type peanut genotypes C724-19-15, C724-19-25 and Georgia-02C...

  9. Influence of root exudates on attachment of Pasteuria penetrans to Meloidogyne arenaria

    USDA-ARS?s Scientific Manuscript database

    We hypothesized that root exudates would influence the spore attachment of Pasteuria penetrans to root-knot nematodes (Meloidogyne arenaria). An experiment was carried out using a factorial arrangement of two single spore (SS) lines cultured from P. penetrans and three single egg mass(SEM)lines cult...

  10. Evaluation of steam and soil solarization for Meloidogyne arenaria control in Florida floriculture crops

    USDA-ARS?s Scientific Manuscript database

    Steam and soil solarization were investigated for control of the root-knot nematode Meloidogyne arenaria in two years of field trials on a commercial flower farm in Florida. The objective was to determine if pre-plant steam treatments in combination with solarization, or solarization alone effective...

  11. Host status of own-rooted Vitis vinifera varieties to Meloidogyne hapla

    USDA-ARS?s Scientific Manuscript database

    Plant-parasitic nematodes are microscopic soil worms that attack the roots of grape plants and cause yield loss. One of the most commonly encountered plant-parasitic nematodes in eastern Washington Vitis vinifera vineyards is Meloidogyne hapla, the northern root-knot nematode. The selection of plant...

  12. Evidence for Reciprocal Selection between Populations of Meloidogyne arenaria and Pasteuria penetrans in a Field Study

    USDA-ARS?s Scientific Manuscript database

    Beginning in 1998, a bioassay using second-stage juveniles (J2) from a greenhouse (GH) population of Meloidogyne arenaria (Ma) was used to monitor endospore densities of the bacterium Pasteuria penetrans, which was parasitizing Ma in a crop rotation study. Spore densities of the bacterium were very...

  13. Molecular and morphological description of Meloidogyne arenaria from traveler’s tree (Ravenala madagascariensis)

    USDA-ARS?s Scientific Manuscript database

    An unusual variant of Meloidogyne arenaria was discovered on roots of a traveler’s tree (Ravenala madagascariensis) intended for display at a public arboretum in Pennsylvania. The population aroused curiosity by the lack of visible galling on the roots of the infected plant. Morphometrics of the pop...

  14. Relationship between Meloidogyne arenaria and Aflatoxin Contamination in Peanut

    PubMed Central

    Timper, P.; Wilson, D. M.; Holbrook, C. C.; Maw, B. W.

    2004-01-01

    Damaged and developing kernels of peanut (Arachis hypogaea) are susceptible to colonization by fungi in the Aspergillus flavus group which, under certain conditions, produces aflatoxins prior to harvest. Our objective was to determine whether infection of peanut roots and pods by Meloidogyne arenaria increases aflatoxin contamination of the kernels when peanut is subjected to drought stress. The experiment was a completely randomized 2-x-2 factorial with 6 replicates/treatment. The treatment factors were nematodes (plus and minus M. arenaria) and fungus (plus and minus A. flavus inoculum). The experiment was conducted in 2001 and 2002 in microplots under an automatic rain-out shelter. In treatments where A. flavus inoculum was added, aflatoxin concentrations were high (> 1,000 ppb) and not affected by nematode infection; in treatments without added fungal inoculum, aflatoxin concentrations were greater (P ≤ 0.05) in kernels from nematode-infected plants (1,190 ppb) than in kernels from uninfected plants (79 ppb). There was also an increase in aflatoxin contamination of kernels with increasing pod galling (r² = 0.83 in 2001, r² = 0.43 in 2002; P ≤ 0.04). Colonization of kernels by A. flavus increased with increasing pod galling (r² = 0.18; P = 0.04) in 2001 but not in 2002. Root-knot nematodes may have a greater role in enhancing aflatoxin contamination of peanut when conditions are not optimal for growth and aflatoxin production by fungi in the A. flavus group. PMID:19262803

  15. Plant Nutrient Partitioning in Coffee Infected with Meloidogyne konaensis

    PubMed Central

    Hurchanik, Denise; Schmitt, D. P.; Hue, N. V.; Sipes, B. S.

    2004-01-01

    Two experiments were conducted to assess nutrient partitioning in coffee (Coffea arabica cv. Typica land race Guatemala) infected with Meloidogyne konaensis. Nutrient levels were quantified from soil, roots, and leaves. In the first experiment, 500-cm3 aliquants of a Kealakekua Andisol were infested with four initial population densities of M. konaensis ranging from 0 to 1,500 freshly hatched second-stage juveniles. Coffee plants (~3 months old) were transplanted into the soil and grown for 25 weeks. Plants responded to nematode infection with decreases (P < 0.05) in concentrations of Ca, Mg, P, and B and increases (P < 0.05) in concentrations of Mn, Cu, Zn, and Ca/B in the roots. Mn and Cu uptake by roots was decreased (P < 0.05) by nematode infection even though concentrations of Mn and Cu increased (P < 0.05) in the roots. Concentrations of Ca and Mg also decreased (P < 0.05) in the leaves, whereas the concentration of Zn increased (P < 0.05). In the second experiment, the soil was amended with Zn at 0 or 5 mg/kg soil and infested with M. konaensis at 0, 100, 1,000 or 10,000 eggs/1,200 cm3 soil. Three-month-old coffee seedlings of similar height were weighed and transplanted into pots and then placed in a greenhouse and grown under 50% shade for 23 weeks. Concentrations of P, K, Ca, Mg, Mn, B, and Zn increased in roots of nematode-free plants growing in Zn-amended soil. The beneficial effects due to the Zn amendment were not apparent in nematode-infected plants. Mn, B, and Zn uptake by coffee roots and P and B concentrations in coffee leaves responded similarly. Management of M. konaensis is necessary to achieve optimal nutrient management in coffee. PMID:19262790

  16. Host Status of Thirteen Acacia Species to Meloidogyne javanica

    PubMed Central

    Ibrahim, Ahmed A. M.; Aref, Ibrahim M.

    2000-01-01

    Thirteen indigenous and exotic Acacia species grown in Saudi Arabia were evaluated for their host status for Meloidogyne javanica in pot tests both in the growth chamber and under outdoor conditions. In both experiments, 21-day-old seedlings were transplanted individually into 15-cm-diam. plastic pots containing a steam-sterilized mixture of equal parts loam and sandy loam. Seedlings were inoculated with 5,000 M. javanica eggs/plant 30 days later. After 120 days, fresh root weight, disease index (1-9 scale), the number of eggs/pot (Pf), eggs/g fresh root, and a reproductive factor (Rf) were determined. Results of both the growth chamber and the outdoor tests were similar. Species were grouped into host suitability categories according to Rf, and they were also grouped into resistance categories based on the sum of gall index, gall size, and percentage of the root system that was galled. Only A. salicina was a poor host and was resistant to M. javanica. Acacia farnisiana, A. gerrardii subsp. negevensis var. najdensis, and A. saligna were excellent hosts and highly susceptible. Both A. nilotica and A. stenophylla were classified as good hosts and highly susceptible, while A. ampliceps, A. ehrenbergiana, A. gerrardii subsp. negevensis var negevensis, A. sclerosperma, A. seyal, A. tortilis, and A. tortilis subsp. spirocarpa were also good hosts but were classified as susceptible rather than highly susceptible. This is the first report on the susceptibility of Acacia species to M. javanica in Saudi Arabia, including some new hosts worldwide. PMID:19271016

  17. Transcriptome analysis of resistant soybean roots infected by Meloidogyne javanica

    PubMed Central

    de Sá, Maria Eugênia Lisei; Conceição Lopes, Marcus José; de Araújo Campos, Magnólia; Paiva, Luciano Vilela; dos Santos, Regina Maria Amorim; Beneventi, Magda Aparecida; Firmino, Alexandre Augusto Pereira; de Sá, Maria Fátima Grossi

    2012-01-01

    Soybean is an important crop for Brazilian agribusiness. However, many factors can limit its production, especially root-knot nematode infection. Studies on the mechanisms employed by the resistant soybean genotypes to prevent infection by these nematodes are of great interest for breeders. For these reasons, the aim of this work is to characterize the transcriptome of soybean line PI 595099-Meloidogyne javanica interaction through expression analysis. Two cDNA libraries were obtained using a pool of RNA from PI 595099 uninfected and M. javanica (J2) infected roots, collected at 6, 12, 24, 48, 96, 144 and 192 h after inoculation. Around 800 ESTs (Expressed Sequence Tags) were sequenced and clustered into 195 clusters. In silico subtraction analysis identified eleven differentially expressed genes encoding putative proteins sharing amino acid sequence similarities by using BlastX: metallothionein, SLAH4 (SLAC1 Homologue 4), SLAH1 (SLAC1 Homologue 1), zinc-finger proteins, AN1-type proteins, auxin-repressed proteins, thioredoxin and nuclear transport factor 2 (NTF-2). Other genes were also found exclusively in nematode stressed soybean roots, such as NAC domain-containing proteins, MADS-box proteins, SOC1 (suppressor of overexpression of constans 1) proteins, thioredoxin-like protein 4-Coumarate-CoA ligase and the transcription factor (TF) MYBZ2. Among the genes identified in non-stressed roots only were Ser/Thr protein kinases, wound-induced basic protein, ethylene-responsive family protein, metallothionein-like protein cysteine proteinase inhibitor (cystatin) and Putative Kunitz trypsin protease inhibitor. An understanding of the roles of these differentially expressed genes will provide insights into the resistance mechanisms and candidate genes involved in soybean-M. javanica interaction and contribute to more effective control of this pathogen. PMID:22802712

  18. Transcriptome analysis of resistant soybean roots infected by Meloidogyne javanica.

    PubMed

    de Sá, Maria Eugênia Lisei; Conceição Lopes, Marcus José; de Araújo Campos, Magnólia; Paiva, Luciano Vilela; Dos Santos, Regina Maria Amorim; Beneventi, Magda Aparecida; Firmino, Alexandre Augusto Pereira; de Sá, Maria Fátima Grossi

    2012-06-01

    Soybean is an important crop for Brazilian agribusiness. However, many factors can limit its production, especially root-knot nematode infection. Studies on the mechanisms employed by the resistant soybean genotypes to prevent infection by these nematodes are of great interest for breeders. For these reasons, the aim of this work is to characterize the transcriptome of soybean line PI 595099-Meloidogyne javanica interaction through expression analysis. Two cDNA libraries were obtained using a pool of RNA from PI 595099 uninfected and M. javanica (J(2)) infected roots, collected at 6, 12, 24, 48, 96, 144 and 192 h after inoculation. Around 800 ESTs (Expressed Sequence Tags) were sequenced and clustered into 195 clusters. In silico subtraction analysis identified eleven differentially expressed genes encoding putative proteins sharing amino acid sequence similarities by using BlastX: metallothionein, SLAH4 (SLAC1 Homologue 4), SLAH1 (SLAC1 Homologue 1), zinc-finger proteins, AN1-type proteins, auxin-repressed proteins, thioredoxin and nuclear transport factor 2 (NTF-2). Other genes were also found exclusively in nematode stressed soybean roots, such as NAC domain-containing proteins, MADS-box proteins, SOC1 (suppressor of overexpression of constans 1) proteins, thioredoxin-like protein 4-Coumarate-CoA ligase and the transcription factor (TF) MYBZ2. Among the genes identified in non-stressed roots only were Ser/Thr protein kinases, wound-induced basic protein, ethylene-responsive family protein, metallothionein-like protein cysteine proteinase inhibitor (cystatin) and Putative Kunitz trypsin protease inhibitor. An understanding of the roles of these differentially expressed genes will provide insights into the resistance mechanisms and candidate genes involved in soybean-M. javanica interaction and contribute to more effective control of this pathogen.

  19. Resistance to Meloidogyne arenaria in Arachis spp. Germplasm

    PubMed Central

    Nelson, S. C.; Simpson, C. E.; Starr, J. L.

    1989-01-01

    Field and greenhouse evaluations of 116 wild Arachis spp. genotypes demonstrated the presence of resistance to reproduction of the root-knot nematode Meloidogyne arenaria race 1. Resistance in greenhouse tests was based on test lines having ≤ 2.5% of the number of eggs per gram of roots as did the susceptible A. hypogaea cv. Tamnut 74. In field tests, resistant genotypes were identified on the basis of having lower (P = 0.05) final nematode population densities than did Tamnut 74. Resistance was identified in genotypes from 11 of 15 wild species tested and in 10 of 20 genotypes belonging to undescribed species. Results of field and greenhouse experiments were similar; 26 of 31 genotypes common to both tests gave similar responses in both tests. Resistance to M. arenaria was identified in the complex hybrid TP-135, which was derived from A. hypogaea cv. Florunner x (A. batizocoi K 9484 x [A. cardenasii GKP 10017 x A. chacoensis GKP 10602])⁴x. In a single greenhouse test, three of six genotypes resistant to M. arenaria were also resistant to M. hapla. These data indicate that the Arachis spp. germplasm contains several sources of resistance to M. arenaria and possibly M. hapla. Some of this resistance is in germplasm that is genetically compatible with A. hypogaea. The complex hybrid TP-135 incorporates resistance from wild species into the genetic background of A. hypogaea. On the basis of these data, we believe it may be possible to develop peanut cultivars with high levels of resistance to M. arenaria and M. hapla. PMID:19287667

  20. Molecular Characterization of Meloidogyne christiei Golden and Kaplan, 1986 (Nematoda, Meloidogynidae) Topotype Population Infecting Turkey Oak (Quercus laevies) in Florida

    PubMed Central

    Brito, J. A.; Subbotin, S. A.; Han, H.; Stanley, J. D.; Dickson, D. W.

    2015-01-01

    Meloidogyne christiei isolated from turkey oak, Quercus laevies, from the type locality in Florida was characterized using isozyme profiles and ribosomal and mitochondrial gene sequences. The phenotype N1a detected from a single egg-laying female of M. christiei showed one very strong band of malate dehydrogenase (MDH) activity; however, no esterase (EST) activity was identified from macerate of one or even 20 females per well. Phylogenetic relationships within the genus Meloidogyne as inferred from Bayesian analysis of partial 18S ribosomal RNA (rRNA), D2-D3 of 28S rRNA, internal transcribed spacer (ITS) rRNA, and cytochrome oxidase subunit II (COII)-16S rRNA of mitochondrial DNA (mtDNA) gene fragments showed that M. christiei formed a separate lineage within the crown group of Meloidogyne and its relationships with any of three Meloidogyne clades were not resolved. PMID:26527837

  1. Host Suitability of the Olive Cultivars Arbequina and Picual for Plant-Parasitic Nematodes

    PubMed Central

    Nico, A. I.; Jiménez-Díaz, R. M.; Castillo, P.

    2003-01-01

    Host suitability of olive cultivars Arbequina and Picual to several plant-parasitic nematodes was studied under controlled conditions. Arbequina and Picual were not suitable hosts for the root-lesion nematodes Pratylenchus fallax, P. thornei, and Zygotylenchus guevarai. However, the ring nematode Mesocriconema xenoplax and the spiral nematodes Helicotylenchus digonicus and H. pseudorobustus reproduced on both olive cultivars. The potential of Meloidogyne arenaria race 2, M. incognita race 1, and M. javanica, as well as P. vulnus and P. penetrans to damage olive cultivars, was also assessed. Picual planting stocks infected by root-knot nematodes showed a distinct yellowing affecting the uppermost leaves, followed by a partial defoliation. Symptoms were more severe on M. arenaria and M. javanica-infected plants than on M. incognita-infected plants. Inoculation of plants with 15,000 eggs + second-stage juveniles/pot of these Meloidogyne spp. suppressed the main height of shoot and number of nodes of Arbequina, but not Picual. Infection by each of the two lesion nematodes (5,000 nematodes/pot) or by each of the three Meloidogyne spp. suppressed (P < 0.05) the main stem diameter of both cultivars. On Arbequina, the reproduction rate of Meloidogyne spp. was higher (P < 0.05) than that of Pratylenchus spp.; on Picual, Pratylenchus spp. reproduction was higher (P < 0.05) than that of Meloidogyne spp. PMID:19265971

  2. Reproduction of Meloidogyne spp. on Resistant Peanut Genotypes from Three Breeding Programs

    PubMed Central

    Timper, P.; Holbrook, C. C.; Anderson, W. F.

    2003-01-01

    Three described species of root-knot nematode parasitize peanut (Arachis hypogaea): Meloidogyne arenaria race 1 (Ma), M. hapla (Mh), and M. javanica (Mj). Peanut cultivars with broad resistance to Meloidogyne spp. will be useful regardless of the species present in the field. The objective of this study was to determine whether peanut genotypes with resistance to M. arenaria originating from three different breeding programs were also resistant to M. hapla and M. javanica. The experiment used a factorial arrangement (completely randomized) with peanut genotype and nematode population as the factors. The five peanut genotypes were 'COAN' and AT 0812 (highly resistant to Ma), C209-6-13 (moderately resistant to Ma), and 'Southern Runner' and 'Georgia Green' (susceptible to Ma). The four nematode populations were two isolates of Ma (Gibbs and Gop) and one isolate each of Mh and Mj. On COAN or AT 0812, both Ma and Mj produced <10% of the eggs produced on Georgia Green. On the peanut genotype C209-6-13, Ma and Mj produced about 50% of the eggs produced on Georgia Green. None of the resistant genotypes exhibited a high level of resistance to Mh. The lack of resistance to Mh in any cultivars or advanced germplasm is a concern because the identity of a Meloidogyne sp. in a particular peanut field is generally not known. Breeding efforts should focus on moving genes for resistance to M. hapla into advanced peanut germplasm, and combining genes for resistance to the major Meloidogyne spp. in a single cultivar. PMID:19262773

  3. Interaction of Meloidogyne javanica and Macrophomina phaseoli in Kenaf Root Rot

    PubMed Central

    Tu, C. C.; Cheng, Y. H.

    1971-01-01

    Incidence and severity of root-rot caused by the fungus Macrophomina phaseoli was increased in screenhouse-grown kenaf (Hibiscus cannabinus L.) seedlings simultaneously infected by the nematode Meloidogyne javanica. In seedlings inoculated at 5, 10 and 15 days of age, root rot lesions increased 70.3, 44.1 and 21.8%, and nematode penetration increased 49.0, 36.7, and 12.3% when both fungus and nematode were present. PMID:19322338

  4. Interaction of Meloidogyne javanica and Macrophomina phaseoli in Kenaf Root Rot.

    PubMed

    Tu, C C; Cheng, Y H

    1971-01-01

    Incidence and severity of root-rot caused by the fungus Macrophomina phaseoli was increased in screenhouse-grown kenaf (Hibiscus cannabinus L.) seedlings simultaneously infected by the nematode Meloidogyne javanica. In seedlings inoculated at 5, 10 and 15 days of age, root rot lesions increased 70.3, 44.1 and 21.8%, and nematode penetration increased 49.0, 36.7, and 12.3% when both fungus and nematode were present.

  5. Effects of Rapeseed and Vetch as Green Manure Crops and Fallow on Nematodes and Soil-borne Pathogens

    PubMed Central

    Johnson, A. W.; Golden, A. M.; Auld, D. L.; Sumner, D. R.

    1992-01-01

    In a rapeseed-squash cropping system, Meloidogyne incognita race 1 and M. javanica did not enter, feed, or reproduce in roots of seven rapeseed cultivars. Both nematode species reproduced at low levels on roots of the third crop of rapeseed. Reproduction of M. incognita and M. javanica was high on squash following rapeseed, hairy vetch, and fallow. The application of fenamiphos suppressed (P = 0.05) root-gall indices on squash following rapeseed, hairy vetch, and fallow; and on Dwarf Essex and Cascade rapeseed, but not Bridger and Humus rapeseed in 1987. The incorporation of 30-61 mt/ha green biomass of rapeseed into the soil 6 months after planting did not affect the population densities of Criconemella ornata, M. incognita, M. javanica, Pythium spp., Rhizoctonia solani AG-4; nor did it consistently increase yield of squash. Hairy vetch supported larger numbers of M. incognita and M. javanica than rapeseed cultivars or fallow. Meloidogyne incognita and M. javanica survived in fallow plots in the absence of a host from October to May each year at a level sufficient to warrant the use of a nematicide to manage nematodes on the following susceptible crop. PMID:19283212

  6. Velvetbean and Bahiagrass as Rotation Crops for Management of Meloidogyne spp. and Heterodera glycines in Soybean.

    PubMed

    Weaver, D B; Rodríguez-Kábana, R; Carden, E L

    1998-12-01

    Soybean (Glycine max) yield often is limited by the phytoparasitic nematodes Meloidogyne spp. and Heterodera glycines in the southeastern United States. We studied the effects of rotation with bahiagrass (Paspalum notatum), velvetbean (Mucuna pruiens), or continuous soybean, aldicarb, and soybean cultivar on yield and population densities in two fields infested with a mixture of Meloidogyne spp. and H. glycines. Velvetbean and bahiagrass reduced population levels of both nematode species to near zero prior to planting soybean. At harvest, both nematode populations were equal in soybean following bahiagrass and continuous soybean but were lower following velvetbean. Both bahiagrass and velvetbean as previous crops were equal in producing significantly (P < 0.003) higher yield than continuous soybean. Velvetbean increased subsequent soybean yield by 98% and bahiagrass increased subsequent soybean yield by 85% as previous crops compared to continuous soybean. The major differences between the two rotation crops were yield response of the nematode-susceptible cultivars and at-harvest nematode populations. Velvetbean tended to mask genetic differences among cultivars more so than bahiagrass. Velvetbean also produced a more long-term effect on nematode populations, with numbers of both Meloidogyne spp. and H. glycines lower in soybean following velvethean than following bahiagrass or continuous soybean.

  7. Velvetbean and Bahiagrass as Rotation Crops for Management of Meloidogyne spp. and Heterodera glycines in Soybean

    PubMed Central

    Weaver, D. B.; Rodríguez-Kábana, R.; Carden, E. L.

    1998-01-01

    Soybean (Glycine max) yield often is limited by the phytoparasitic nematodes Meloidogyne spp. and Heterodera glycines in the southeastern United States. We studied the effects of rotation with bahiagrass (Paspalum notatum), velvetbean (Mucuna pruiens), or continuous soybean, aldicarb, and soybean cultivar on yield and population densities in two fields infested with a mixture of Meloidogyne spp. and H. glycines. Velvetbean and bahiagrass reduced population levels of both nematode species to near zero prior to planting soybean. At harvest, both nematode populations were equal in soybean following bahiagrass and continuous soybean but were lower following velvetbean. Both bahiagrass and velvetbean as previous crops were equal in producing significantly (P < 0.003) higher yield than continuous soybean. Velvetbean increased subsequent soybean yield by 98% and bahiagrass increased subsequent soybean yield by 85% as previous crops compared to continuous soybean. The major differences between the two rotation crops were yield response of the nematode-susceptible cultivars and at-harvest nematode populations. Velvetbean tended to mask genetic differences among cultivars more so than bahiagrass. Velvetbean also produced a more long-term effect on nematode populations, with numbers of both Meloidogyne spp. and H. glycines lower in soybean following velvethean than following bahiagrass or continuous soybean. PMID:19274247

  8. A Pathotype System to Describe Intraspecific Variation in Pathogenicity of Meloidogyne chitwoodi

    PubMed Central

    Van der Beek, J. G.; Maas, P. W. Th.; Janssen, G. J. W.; Zijlstra, C.; Van Silfhout, C. H.

    1999-01-01

    Tests of eight Dutch Meloidogyne chitwoodi isolates to the differential set for host races 1 and 2 in M. chitwoodi provided no evidence for the existence of host race 2 in the Netherlands. The data showed deviations from expected reactions on the differential hosts, which raised doubts of the usefulness of the host race classification in M. chitwoodi. The term ''pathotype'' is proposed for groups of isolates of one Meloidogyne sp. that exhibit the same level of pathogenicity on genotypes of one host species. We recommend that the pathotype classification be applied in pathogen-host relationships when several genotypes of a Meloidogyne sp. are tested on several genotypes of one host species. Three pathotypes of M. chitwoodi were identified on Solanum bulbocastanum, suggesting at least two different genetic factors for virulence and resistance in the pathogen and the host species, respectively. The occurrence of several virulence factors in M. chitwoodi will complicate the successful application of resistance factors from S. bulbocastanum for developing resistant potato cultivars. PMID:19270911

  9. Occurrence of Meloidogyne fallax in North America, and molecular characterization of M. fallax and M. minor from U.S. golf course greens

    USDA-ARS?s Scientific Manuscript database

    Several species of root-knot nematodes (Meloidogyne spp.) are known to have significant presence on turf grass in golf course greens, particularly in the western United States. Nematodes isolated from a golf course in King Co., Washington were identified as Meloidogyne minor based on analysis of the...

  10. Clinical and mycological analysis of twenty-one cases of tinea incognita in the Aegean region of Turkey: a retrospective study.

    PubMed

    Turk, Bengu Gerceker; Taskin, Banu; Karaca, Nezih; Sezgin, Aycan Ozden; Aytimur, Derya

    2013-01-01

    Tinea incognita is a dermatophyte infection with atypical clinical features modified by the improper use of corticosteroids or calcineurin inhibitors. The aim of this study was to analyze clinical and microbiological features of patients with tinea incognita. A total of 6326 patients referred to mycology laboratory between January 2008 and January 2011 for mycological examination with a diagnosis of tinea incognita were reviewed retrospectively. Twenty-one patients, 13 (61.9%) women and 8 (38.1%) men, mean age 42.2±36.8, were included in the study. Of them, lesions were localized in 15 (71.4%) patients and widespread in six (28.6%) patients. The mean duration of the disease was 9.5 (range 1-120) months. All patients had a history of treatment with steroids. Before admission, most of them had been misdiagnosed as eczema or psoriasis. Microscopic examination revealed hyphae and spores in most of the cases (n=17, 80.95%). Mycological cultures were positive in 19 (90.5%) patients. The most frequently isolated dermatophyte was Trichophyton rubrum (n=14, 66.7%). This case series revealed Trichophyton rubrum as the most frequent agent of tinea incognita. To the best of our knowledge, this is the largest case series from Turkey describing clinical features and mycological agents of tinea incognita.

  11. [Evaluation of the resistance to two nematodes: Radopholus similis and Meloidogyne spp. in four banana genotypes in Morocco].

    PubMed

    Guedira, Abdelkarim; Rammah, Abdellah; Triqui, Zine-el-abidine; Chlyah, Hassan; Chlyah, Bouchra; Haïcour, Robert

    2004-08-01

    Radopholus similis and Meloidogyne spp. are the main nematode parasites of banana plants grown under plastic shelters in Morocco. A test was made in pots to evaluate the resistance of four genotypes of banana to these nematodes. Infection by Meloidogyne spp. brought about an increase in root weight in all banana plants tested because of gall formation. The inoculation of R. similis produced a reduction in length and diameter of the pseudo-trunk as well as in root and aerial mass in all genotypes. Pisang jari buaya showed the significantly lowest number of Meloidogyne nematodes per 10 g of roots, whereas for R. similis, the significantly smallest numbers were obtained in Pisang berlin and Pisang jari buaya. Therefore, Pisang jari buaya was the only banana genotype studied to show some degree of resistance to both nematodes.

  12. Influence of Pratylenchus vulnus and Meloidogyne hapla on the Growth of Rootstocks of Rose

    PubMed Central

    Santo, G. S.; Lear, Bert

    1976-01-01

    Pratylenchus vulnus is involved in a desease of Rosa noisettiana 'Manetti' rose rootstock characterized by darkening of roots, death of feeder roots, and stunting of entire plants. The disease is more severe when plants are grown in silt loam soil than when they are grown in sandy loam soil. The nematodes reproduce best in silt loam soil at 20 C. Meloidogyne hapla did not affect the growh of Manetti. Rosa sp. 'Dr. Huey', Manetti, and R. odorata rose rootstocks were found to be goos hosts for P. vulnus whereas R. multiflora was less suitable. M. hapla reproduced well on R. odorata, Dr. Huey, and R. multiflora, but not on Manetti. PMID:19308189

  13. A Taqman real-time PCR assay for detection of Meloidogyne hapla in root galls and in soil

    USDA-ARS?s Scientific Manuscript database

    Meloidogyne hapla is one of the most widespread and serious soil-borne nematodes causing root knot diseases in various crops. Early and accurate detection and quantification of M. hapla in soil is essential for effective disease management. The purpose of this study was to develop an assay for detec...

  14. Calcium is involved in the RMc1(blb)-mediated hypersensitive response against Meloidogyne chitwoodi in potato

    USDA-ARS?s Scientific Manuscript database

    The resistance (R) gene RMc1(blb) confers resistance against the plant-parasitic nematode, Meloidogyne chitwoodi. Avirulent and virulent nematodes were used to functionally characterize the RMc1(blb)-mediated resistance mechanism in potato (Solanum tuberosum). Histological observations indicated a h...

  15. RNA interference of effector gene Mc16D10L confers resistance against meloidogyne chitwoodi in arabidopsis and potato

    USDA-ARS?s Scientific Manuscript database

    Potatoes (Solanum tuberosum) are the most important non-cereal food crop. The Columbia root-knot nematode (Meloidogyne chitwoodi), a quarantine pathogen, is a significant problem in some of the major potato-producing areas worldwide. In spite of great genetic diversity in wild potato species, no com...

  16. Evaluation of steam for Meloidogyne Arenaria control in production of in-ground floriculture crops in Florida

    USDA-ARS?s Scientific Manuscript database

    Steam and soil solarization were investigated for control of the root-knot nematode Meloidogyne arenaria in two years of field trials on a commercial flower farm in Florida. The objective was to determine if pre-plant steam treatments in combination with solarization, or solarization alone effective...

  17. Impact of grapevine (Vitis vinifera) varieties on reproduction of the northern root-knot nematode (Meloidogyne hapla)

    USDA-ARS?s Scientific Manuscript database

    Plant-parasitic nematodes are microscopic soil worms that attack the roots of grape plants and cause yield loss. One of the most commonly encountered plant-parasitic nematodes in eastern Washington Vitis vinifera vineyards is Meloidogyne hapla, the northern root-knot nematode. The selection of plant...

  18. Molecular and morphological characterization of an unusual Meloidogyne arenaria population from traveler’s tree (Ravenala madagascariensis)

    USDA-ARS?s Scientific Manuscript database

    An unusual Meloidogyne arenaria population was discovered on roots of a traveler’s tree (Ravenala madagascariensis) intended for display at a public arboretum in Pennsylvania. The population aroused curiosity by the lack of visible galling on the roots of the infected plant, and the females were typ...

  19. Effects of Temperature on Resistance in Phaseolus vulgaris Genotypes and on Development of Meloidogyne Species

    PubMed Central

    Sydenham, G. M.; McSorley, R.; Dunn, R. A.

    1997-01-01

    Phaseolus vulgaris lines with heat-stable resistance to Meloidogyne spp. may be needed to manage root-knot nematodes in tropical regions. Resistance expression before and during the process of nematode penetration and development in resistant genotypes were studied at pre- and postinoculation temperatures of 24 °C and 24 °C, 24 °C and 28 °C, 28 °C and 24 °C, and 28 °C and 28 °C. Resistance was effective at all temperature regimes examined, with fewer nematodes in roots of a resistant line compared with a susceptible line. Preinoculation temperature did not modify resistance expression to later infections by root-knot nematodes. However, postinoculation temperatures affected development of Meloidogyne spp. in both the resistant and susceptible bean lines tested. The more rapid development of nematodes to adults at the higher postinoculation temperature of 28 °C in both bean lines suggests direct temperature effects on nematode development instead of on resistance expression of either of two gene systems. Also, resistance was stable at 30 °C and 32 °C. PMID:19274137

  20. Characterization of a Root-Knot Nematode Population of Meloidogyne arenaria from Tupungato (Mendoza, Argentina)

    PubMed Central

    Evangelina García, Laura; Sánchez-Puerta, María Virginia

    2012-01-01

    Root-knot nematodes (Meloidogyne spp.) are polyphagous plant parasites of global importance. Successful host infection depends on the particular interaction between a specific nematode species and race and a specific plant species and cultivar. Accurate diagnosis of nematode species is relevant to effective agricultural management; and benefits further from understanding the variability within a single nematode species. Here, we described a population of M. arenaria race 2 from Mendoza (Argentina). This study represents the first morphometric, morphological, biochemical, reproductive, molecular, and host range characterization of a root-knot nematode species from Argentina. Even after gathering morphological and morphometric data of this population and partially sequencing its rRNA, an unequivocal taxonomic assignment could not be achieved. The most decisive data was provided by esterase phenotyping and molecular methods using SCARs. These results highlight the importance of taking a multidimensional approach for Meloidogyne spp. diagnosis. This study contributes to the understanding of the variability of morphological, reproductive and molecular traits of M. arenaria, and provides data on the identification of root-knot nematodes on tomato cultivars from Argentina. PMID:23481918

  1. Reproduction of Meloidogyne javanica on Plant Roots Genetically Transformed by Agrobacterium rhizogenes.

    PubMed

    Verdejo, S; Jaffee, B A; Mankau, R

    1988-10-01

    Reproduction of Meloidogyne javanica was compared on several Agrobacterium rhizogenes-transformed root cultures under monoxenic conditions. M. javanica reproduced on all transformed roots tested; however, more females and eggs were obtained on potato and South Australian Early Dwarf Red tomato than on bindweed, Tropic tomato, lima bean, or carrot. Roots that grew at moderate rates into the agar and produced many secondary roots supported the highest reproduction. Numbers of females produced in cultures of transformed potato roots increased with increasing nematode inoculum levels, whether inoculum was dispersed eggs or juveniles. Females appeared smaller, produced fewer eggs, and were found in coalesced galls at the higher inoculum levels. The ratio between the final and initial population decreased sharply as the juvenile inoculum increased. The second-stage juvenile was preferred to dispersed eggs or egg masses for inoculation of tissue culture systems because quantity and viability of inoculum were easily assessed. Meloidogyne javanica reared on transformed root cultures were able to complete their life cycles on new transformed root cultures or greenhouse tomato plants.

  2. Ecological Relationships between Meloidogyne spartinae and Salt Marsh Grasses in Connecticut

    PubMed Central

    Elmer, W. H.

    2008-01-01

    Healthy specimens of selected grasses were collected from salt marshes and grown in the greenhouse. Plants were inoculated with Meloidogyne spartinae to determine the host range of this nematode. After 12 weeks, Spartina alterniflora plants formed root galls in response to infection and increased M. spartinae populations. Spartina patens, Spartina cynosuroides, Juncus gerardii and Distichlis spicata were non-hosts. In order to determine the natural distribution of M. spartinae in dieback areas, S. alterniflora plants were sampled from transects adjacent to dieback areas in Madison, CT, at low tide. Plants were sampled at the top or the creek and at 1-m intervals to the lowest area of plant growth at the low tide water's edge. Five samples were taken over an elevation drop of 90 cm. Two transects were taken each day on 21 June and 5 July 2007, and one transect was taken on 31 October 2007. Meloidogyne spartinae galls per gram root were higher at the higher elevations. In late June and early July 2007, M. spartinae developed more quickly in the higher elevations, perhaps because peat and sediments were drier and warmer away from low tide water levels. The effects of M. spartinae on S. alterniflora and the role of the nematode in marsh decline and dieback in the northeast United States remain to be determined. PMID:19440262

  3. Effects of biosolid amendment on populations of Meloidogyne hapla and soils with different textures and pHs.

    PubMed

    Mennan, Sevilhan; Melakeberhan, Haddish

    2010-09-01

    Temperate vegetable and nursery industries face significant challenges in managing Meloidogyne hapla, a plant-parasite for which few resistant cultivars and/or viable alternatives to methyl bromide exist. N-Viro Soil(R) (NVS), an alkaline-stabilized biosolid product, has soil nutrition enrichment capacity and potential for plant-parasitic nematode suppression. In three sets of experiments, we investigated the effects of NVS on M. hapla populations from Rhode Island (RI), Connecticut (CT), New York, Geneva (NYG) and Lyndonville (NYL), and Michigan (MI), and growth of tomato cv 'Rutgers' in five soils commonly used for vegetable and nursery crop production in the Great Lakes Region of the USA. Either 0 (control) or 600 eggs/100 cm(3) of soil per M. hapla population were added in all experiments. In the first set, NVS was applied at rates of 0, 1, 2 and 4 g/100 cm(3) of sandy loam soil (pH 7) and resulted in variable responses on the numbers of nematodes recovered and plant growth at 30 and 90 days (25+/-2 degrees C); however, the 2g NVS treatment consistently increased plant growth. Either 0 or 2 NVS/100 cm(3) were applied to a coarse loamy (pH 4.5) and sandy loam (pH 8, second set of experiments), and muck (pH 5.5), loamy sand (pH 7.1) and sandy loam (pH 7.5, third set of experiments) soils and experiments terminated four weeks after nematode inoculation. Across experiments, the effect of NVS on the M. hapla populations varied. Generally nematode infection decreased plant growth. NVS increased soil pH the most in muck and the least in sandy loam soil. The most consistent interaction effects of NVS*soil, NVS*M. hapla, soil*M. hapla and/or NVS*soil*M. hapla across the experiments indicate that NVS affects M. hapla populations in different ways in different soil types, suggesting that NVS application is likely to be site-specific. These findings further provide basis that may potentially explain reports of variable effects of NVS on nematodes and how future studies may

  4. Organic and Inorganic Nitrogen Amendments to Soil as Nematode Suppressants

    PubMed Central

    Rodríguez-Kábana, R.

    1986-01-01

    Inorganic fertilizers containing ammoniacal nitrogen or formulations releasing this form of N in the soil are most effective for suppressing nematode populations. Anhydrous ammonia has been shown to reduce soil populations of Tylenchorhynchus claytoni, Helicotylenchus dihystera, and Heterodera glycines. The rates required to obtain significant suppression of nematode populations are generally in excess of 150 kg N/ha. Urea also suppresses several nematode species, including Meloidogyne spp., when applied at rates above 300 kg N/ha. Additional available carbon must be provided with urea to permit soil microorganisms to metabolize excess N and avoid phytotoxic effects. There is a direct relation between the amount of "protein" N in organic amendments and their effectiveness as nematode population suppressants. Most nematicidal amendments are oil cakes, or animal excrements containing 2-7% (w:w) N; these materials are effective at rates of 4-10 t/ha. Organic soil amendments containing mucopolysaccharides (e.g., mycelial wastes, chitinous matter) are also effective nematode suppressants. PMID:19294153

  5. Strip-tilled cover cropping for managing nematodes, soil mesoarthropods, and weeds in a bitter melon agroecosystem.

    PubMed

    Marahatta, Sharadchandra P; Wang, Koon-Hui; Sipes, Brent S; Hooks, Cerruti R R

    2010-06-01

    A field trial was conducted to examine whether strip-tilled cover cropping followed by living mulch practice could suppress root-knot nematode (Meloidogyne incognita) and enhance beneficial nematodes and other soil mesofauna, while suppressing weeds throughout two vegetable cropping seasons. Sunn hemp (SH), Crotalaria juncea, and French marigold (MG), Tagetes patula, were grown for three months, strip-tilled, and bitter melon (Momordica charantia) seedlings were transplanted into the tilled strips; the experiment was conducted twice (Season I and II). Strip-tilled cover cropping with SH prolonged M. incognita suppression in Season I but not in Season II where suppression was counteracted with enhanced crop growth. Sunn hemp also consistently enhanced bacterivorous and fungivorous nematode population densities prior to cash crop planting, prolonged enhancement of the Enrichment Index towards the end of both cash crop cycles, and increased numbers of soil mesoarthropods. Strip-tilled cover cropping of SH followed by clipping of the living mulch as surface mulch also reduced broadleaf weed populations up to 3 to 4 weeks after cash crop planting. However, SH failed to reduce soil disturbance as indicated by the Structure Index. Marigold suppressed M. incognita efficiently when planted immediately following a M. incognita-susceptible crop, but did not enhance beneficial soil mesofauna including free-living nematodes and soil mesoarthropods. Strip-tilled cover cropping of MG reduced broadleaf weed populations prior to cash crop planting in Season II, but this weed suppression did not last beyond the initial cash crop cycle.

  6. Strip-tilled Cover Cropping for Managing Nematodes, Soil Mesoarthropods, and Weeds in a Bitter Melon Agroecosystem

    PubMed Central

    Wang, Koon-Hui; Sipes, Brent S.; Hooks, Cerruti R.R.

    2010-01-01

    A field trial was conducted to examine whether strip-tilled cover cropping followed by living mulch practice could suppress root-knot nematode (Meloidogyne incognita) and enhance beneficial nematodes and other soil mesofauna, while suppressing weeds throughout two vegetable cropping seasons. Sunn hemp (SH), Crotalaria juncea, and French marigold (MG), Tagetes patula, were grown for three months, strip-tilled, and bitter melon (Momordica charantia) seedlings were transplanted into the tilled strips; the experiment was conducted twice (Season I and II). Strip-tilled cover cropping with SH prolonged M. incognita suppression in Season I but not in Season II where suppression was counteracted with enhanced crop growth. Sunn hemp also consistently enhanced bacterivorous and fungivorous nematode population densities prior to cash crop planting, prolonged enhancement of the Enrichment Index towards the end of both cash crop cycles, and increased numbers of soil mesoarthropods. Strip-tilled cover cropping of SH followed by clipping of the living mulch as surface mulch also reduced broadleaf weed populations up to 3 to 4 weeks after cash crop planting. However, SH failed to reduce soil disturbance as indicated by the Structure Index. Marigold suppressed M. incognita efficiently when planted immediately following a M. incognita-susceptible crop, but did not enhance beneficial soil mesofauna including free-living nematodes and soil mesoarthropods. Strip-tilled cover cropping of MG reduced broadleaf weed populations prior to cash crop planting in Season II, but this weed suppression did not last beyond the initial cash crop cycle. PMID:22736847

  7. Characterization of Isolates of Meloidogyne from Rice-Wheat Production Fields in Nepal

    PubMed Central

    Pokharel, Ramesh R.; Abawi, George S.; Zhang, Ning; Duxbury, John M.; Smart, Christine D.

    2007-01-01

    Thirty-three isolates of root-knot nematode were recovered from soil samples from rice-wheat fields in Nepal and maintained on rice cv. BR 11. The isolates were characterized using morphology, host range and DNA sequence analyses in order to ascertain their identity. Results indicated phenotypic similarity (juvenile measurements, perennial pattern, host range and gall shape) of the Nepalese isolates with Meloidogyne graminicola, with minor variations. The rice varieties LA 110 and Labelle were susceptible to all of the Nepalese isolates, but differences in the aggressiveness of the isolates were observed. Phylogenetic analyses based on the sequences of partial internal transcribed spacer (ITS) of the rRNA genes indicated that all Nepalese isolates formed a distinct clade with known isolates of M. graminicola with high bootstrap support. Furthermore, two groups were identified within the M. graminicola clade. No correlation between ITS haplotype and aggressiveness or host range was found among the tested isolates. PMID:19259491

  8. Efficacy of Fumigant and Nonfurmigant Nematicides for Control of Meloidogyne arenaria on Peanut.

    PubMed

    Dickson, D W; Hewlett, T E

    1988-10-01

    Three tests were conducted to evaluate the efficacy of fumigant and nonfumigant nematicides for control of Meloidogyne arenaria race 1 on peanut. Methyl bromide, 1,3-D, methyl isothiocyanate, and methyl isothiocyanate mixtures were applied 7 or 8 days preplant either broadcast or in-the-row. Aldicarb, ethoprop, fenamiphos, and F5145 were applied at different rates and by different methods at-plant or at early flowering. Of the 32 treatments evaluated, only seven resulted in yield increases (P = 0.05), although early season vigor was high in all treated plots. During the latter one-third of the growing season, however, nematode control was not adequate in most treatments resulting in heavy peg, pod, and root infection by M. arenaria.

  9. Below-Ground Attack by the Root Knot Nematode Meloidogyne graminicola Predisposes Rice to Blast Disease.

    PubMed

    Kyndt, Tina; Zemene, Henok Yimer; Haeck, Ashley; Singh, Richard; De Vleesschauwer, David; Denil, Simon; De Meyer, Tim; Höfte, Monica; Demeestere, Kristof; Gheysen, Godelieve

    2017-03-01

    Magnaporthe oryzae (rice blast) and the root-knot nematode Meloidogyne graminicola are causing two of the most important pathogenic diseases jeopardizing rice production. Here, we show that root-knot nematode infestation on rice roots leads to important above-ground changes in plant immunity gene expression, which is correlated with significantly enhanced susceptibility to blast disease. A detailed metabolic analysis of oxidative stress responses and hormonal balances demonstrates that the above-ground tissues have a disturbed oxidative stress level, with accumulation of H2O2, as well as hormonal disturbances. Moreover, double infection experiments on an oxidative stress mutant and an auxin-deficient rice line indicate that the accumulation of auxin in the above-ground tissue is at least partly responsible for the blast-promoting effect of root-knot nematode infection.

  10. Host Tests to Differentiate Meloidogyne chitwoodi Races 1 and 2 and M. hapla

    PubMed Central

    Mojtahedi, H.; Santo, G. S.; Wilson, J. H.

    1988-01-01

    The reproductive factor (R = final egg density at 55 days ÷ 5,000, initial egg density) of Meloidogyne chitwoodi race 2 (alfalfa race) on 46 crop cultivars ranged from 0 to 130. The reproductive efficiency of M. chitwoodi race 1 (non-alfalfa race) and M. chitwoodi race 2 was compared on selected crop cultivars. The basic difference between the two races lay in their differential reproduction on Thor alfalfa and Red Cored Chantenay carrot. M. chitwoodi race 2 reproduced on alfalfa but not on carrot. Conversely, alfalfa was a poor host and carrots were suitable for M. chitwoodi race 1. Based on host responses to M. chitwoodi races and M. hapla, a new differential host test was proposed to distinguish the common root-knot nematode species of the Pacific Northwest. PMID:19290239

  11. Evaluation of Fosthiazate for Management of Meloidogyne javanica in Florida Flue-cured Tobacco

    PubMed Central

    Rich, J. R.; Dunn, R. A.; Thomas, W. D.; Breman, J. W.; Tervola, R. S.

    1994-01-01

    One grower trial and two experiment station tests were conducted to evaluate a new nematicide, fosthiazate, for management of Meloidogyne javanica in Florida flue-cured tobacco. Fosthiazate was applied broadcast and incorporated at rates ranging from 21 to 84 g/100 m² and compared with 1,3-dichloropropene at 240 and 460 ml/100 m² and fenamiphos at 67 g/100 m². All fosthiazate treatments increased tobacco yields and reduced root galling. Application of 1,3-D provided the highest tobacco yields and greatest reductions in root galling. The fenamiphos treatment outperformed all fosthiazate treatments in tobacco yield and root gall reduction. Fosthiazate may therefore have limited utility compared with 1,3-D and fenamiphos as a nematicide for tobacco in peninsular Florida. PMID:19279951

  12. Description of the Blueberry Root-knot Nematode, Meloidogyne carolinensis n. sp.

    PubMed

    Eisenback, J D

    1982-07-01

    Meloidogyne carolinensis n. sp. is described from cultivated highbush blueberry (cultivars derived from hybrids of Vaccinium corymbosum L. and V. lamarckii Camp) in North Carolina. The perineal pattern of the female has a large cuticular ridge that surrounds the perivulval area, and the excretory pore is near the level of the base of the stylet. The stylet is 15.9 mum long and the knobs gradually merge with the shaft. The head shape and stylet morphology of the male are quite variable. The typical head and four variants, as well as the typical stylet and two variants, are described. The labial disc, medial lips, and lateral lips of second-stage juveniles are fused and in the same contour. The head region is not annulated. Mean juvenile length is 463.7 mum, stylet length is 11.9 mum, and tail length is 42.5 mum.

  13. Host Range and Distribution of the Clover Root-knot Nematode, Meloidogyne trifoliophila

    PubMed Central

    Bernard, E. C.; Jennings, P. L.

    1997-01-01

    The ability of Meloidogyne trifoliophila to gall 230 species and cultivars of plants was determined in a greenhouse. All clovers (Trifolium spp.) were severely galled regardless of species or cultivar. Most soybean cultivars were moderately to severely galled. Among other legumes, broad bean, garden pea, Korean lespedeza, sweetclover, and common vetch were good hosts, but alfalfa, bird's-foot trefoil, peanut, and pole bean were poor or nonhosts. Among other plant families, most Apiaceae (Umbelliferae) and Brassicaceae (Cruciferae) were galled, but Cucurbitaceae, Iridaceae, Malvaceae, Poaceae, and Solanaceae were rarely or never galled. Results for Amaryllidaceae, Asteraceae, Lamiaceae, and Liliaceae were variable. This nematode was not found in a survey of pasture and soybean fields in southwestern Tennessee. PMID:19274266

  14. Competition between the Plant-parasitic Nematodes Pratylenchus neglectus and Meloidogyne chitwoodi

    PubMed Central

    Umesh, Kodira C.; Ferris, Howard; Bayer, David E.

    1994-01-01

    In experiments on competition between Pratylenchus neglectus and Meloidogyne chitwoodi in barley, the species that parasitized the roots first inhibited penetration by the latter species. Prior presence of P. neglectus impeded the development of M. chitwoodi. Pratylenchus neglectus reduced egg production, final population levels, and reproductive index of M. chitwoodi. The reduction was linearly related to initial population densities of P. neglectus. Initial population densities of M. chitwoodi had no effect on final population levels of P. neglectus. Carbon assimilation by barley plants was reduced when either nematode species was present alone, but not when both were present together. Both nematode species assimilated lower amounts of carbon when present together than when present alone. A split-root experiment demonstrated that translocatable chemicals were not involved in the competition between the two species. PMID:19279894

  15. Spatial-temporal Patterns of Meloidogyne konaensis on Coffee in Hawaii

    PubMed Central

    Zhang, Fengru; Schmitt, D. P.

    1995-01-01

    Population densities ofMeloidogyne konaensis were determined in March and July of 1991 and 1992 on coffee cultivars Guatemalan and 502, and on four rootstocks (Purpuree, Congensis, Deweveri, and Kaffe) with Guatemalan or 502 as a scion. Three-dimensional spatial patterns were characterized on roots of Guatemalan and Deweveri. Population densities differed among rootstocks (P < 0.05) and times (P < 0.01). The greatest number of second-stage juveniles (J2) occurred on Guatemalan and fewest J2 on Purpuree and Deweveri rootstocks. More nematodes were found in March than in July of both years. The spatial distribution varied by positions and depths on Guatemalan. The highest nematode population density occurred at 60 cm from the base of the tree and 15-45 cm deep. Numbers of nematodes were relatively low at all positions and all depths on the Guatemalan-Deweveri combination. PMID:19277268

  16. Meloidogyne aberrans sp. nov. (Nematoda: Meloidogynidae), a new root-knot nematode parasitizing kiwifruit in China.

    PubMed

    Tao, Ye; Xu, Chunling; Yuan, Chunfen; Wang, Honghong; Lin, Borong; Zhuo, Kan; Liao, Jinling

    2017-01-01

    High infection rates of roots of wild kiwifruit (Actinidia chinensis Planch) and soil infestation by a root-knot nematode were found in Anshun, GuiZhou Province, China. Morphology, esterase phenotype and molecular analyses confirmed that this nematode was different from previously described root-knot nematodes. In this report, the species is described, illustrated and named Meloidogyne aberrans sp. nov. The new species has a unique combination of characters. A prominent posterior protuberance, round and faint perineal pattern and a medium-length stylet (13.6-15.5 μm) characterized the females. Second-stage juveniles (J2) were characterized by a smooth lip region with distinctly protruded medial lips and a depression in outline at the oral aperture, a relatively long stylet (15.9-16.8 μm), four incisures in the lateral field and a very short, even poorly defined, hyaline tail terminus (2.2-5.5 μm). More incisures (11-15) existed in the lateral field of males, and the stylet and spicules of males were 18.2-19.6 μm and 22.7-36.8 μm long respectively. Egg masses were typically produced within the roots of kiwifruit. The new species had a rare Est phenotype, S2. Phylogenetic trees inferred from SSU, LSU D2D3, ITS, and partial coxII-16S rRNA revealed that M. aberrans sp. nov. was within the Meloidogyne clade and was distinguished from all described root-knot nematodes. Moreover, from histopathological observations, M. aberrans sp. nov. induced the formation of multinucleate giant cells.

  17. Identifying rates of meadowfoam (Limnanthes alba) seed meal needed for suppression of Meloidogyne hapla and Pythium irregulare in soil

    USDA-ARS?s Scientific Manuscript database

    Meadowfoam (Limnanthes alba) is a commercial oilseed crop grown in Oregon. After extracting oil from seed, the remaining seed meal is rich in the secondary plant metabolite glucolimnanthin, which can be converted into pesticidal compounds such as 3-methoxybenzyl isothiocyanate (ITC) and 3-methoxyphe...

  18. Effect of Soil Temperature on the Pathogenicity and Reproduction of Meloidogyne chitwoodi and M. hapla on Russet Burbank potato

    PubMed Central

    Santo, G. S.; O'Bannon, J. H.

    1981-01-01

    Meloidogyne chitwoodi and M. hapla were pathogenic to both roots and tubers of Russet Burbank potato. Both species affected root growth at 15, 20, and 25 C, but not 30 C. Meloidogyne chitwoodi reprotluced best at 15, 20, and 25 C and M. hapla at 25 and 30 C. Reproduction of M. chitwoodi was reduced at 30 C; reproduction of M. hapla was reduced at 15 C and less at 20 C. The reproductive potential of M. chitwoodi was higher than that of M. hapla at 15, 20, and 25 C. M. hapla reproduced better at 30 C than did M. chitwoodi. M. chitwoodi infected potato tubers in higher numbers than did M. hapla. PMID:19300793

  19. Comparison of saline tolerance among genetically similar species of Fusarium and Meloidogyne recovered from marine and terrestrial habitats

    NASA Astrophysics Data System (ADS)

    Elmer, W. H.; LaMondia, J. A.

    2014-08-01

    Successful plant pathogens co-evolve and adapt to the environmental constraints placed on host plants. We compared the salt tolerance of two salt marsh pathogens, Fusarium palustre and Meloidogyne spartinae, to genetically related terrestrial species, F. sporotrichioides and Meloidogyne hapla, to assess whether the salt marsh species had acquired selective traits for persisting in saline environments or if salt tolerance was comparable among Fusarium and Meloidogyne species. Comparisons of both species were made in vitro in vessels containing increasing concentration of NaCl. We observed that F. palustre was more tolerant to NaCl than F. sporotrichioides. The radial expansion of F. palustre on NaCl-amended agar plates was unaffected by increasing concentrations up to 0.3 M. F. sporotrichioides showed large reductions in growth at the same concentrations. Survival of M. hapla was greatest at 0 M, and reduced by half in a 0.3 M solution for 4 days. No juveniles survived exposure to 0.3 M NaCl for 12 days. M. spartinae survived at all NaCl concentrations tested, including 1.0 M for at least 12 days. These findings are consistent with the hypothesis that marine organisms in the upper tidal zone must osmoregulate to withstand a wide range of salinity and provide evidence that these pathogens evolved in saline conditions and are not recent introductions from terrestrial niches.

  20. Identification of resistance to Meloidogyne javanica in the Lycopersicon peruvianum complex.

    PubMed

    Veremis, J C; Roberts, P A

    1996-10-01

    Clones of Lycopersicon peruvianum PI 2704352R2, PI 270435-3MH and PI 126443-1MH expressed novel resistance to three Mi-avirulent M. javanica isolates in greenhouse experiments. Clones from PI 126443-1MH were resistant to the three M. javanica isolates at 25°C. The three isolates were able to reproduce on one embryorescue hybrid of PI 126443-1MH, but not on three L. peruvianum-L. esculentum bridge-line hybrids of PI 1264431MH when screened at 25°C (Mi-expressed temperature). Clones of PI 270435-2R2 and all its hybrids with susceptible genotypes were resistant to the three M. javanica isolates at 25°C. The bridge-line hybrid EPP-2xPI 2704352R2 was susceptible to M. javanica isolate 811 at 32°C, whereas PI 270435-2R2 and all other hybrids of PI 27043 5-2R2 crossed with susceptible genotypes were resistant at 32°C. At 32°C, one F2 progeny of PI 126443-IMHxEPP-1, and three test-cross progenies of PI 1264409MHx[PI 270435-3MHxPI 126443-1MH], and reciprocal test-cross progenies of [PI 270435-3MHxPI 2704352R2]xPI 126440-9MH, each segregated into resistant: susceptible (R∶S) ratios close to 3∶1. The results from the F2 progeny indicated that heat-stable resistance to Mi-avirulent M. javanica in PI 126443 -1MH is conferred by a single dominant gene. The results from the test-crosses indicated that this gene in PI 126443-1MH is different from the resistance gene in PI 270435-3MH. The resistance gene in PI 270435-3MH was also shown to differ from the resistance factor in PI 270435-2R2. The expression of differential susceptibility and resistance to M. javanica and M. incognita in individual plants of the bridge-line hybrid, embryo-rescue hybrid, F2, and test-crosses indicated that at least some genes governing resistance to M. javanica differ from the genes conferring resistance to M. incognita. A new source of heat-stable resistance to M. javanica was identified in Lycopersicon chilense.

  1. Evaluation of Steam and Soil Solarization for Meloidogyne arenaria Control in Florida Floriculture Crops.

    PubMed

    Kokalis-Burelle, Nancy; Rosskopf, Erin N; Butler, David M; Fennimore, Steven A; Holzinger, John

    2016-09-01

    Steam and soil solarization were investigated for control of the root-knot nematode Meloidogyne arenaria in 2 yr of field trials on a commercial flower farm in Florida. The objective was to determine if preplant steam treatments in combination with solarization, or solarization alone effectively controlled nematodes compared to methyl bromide (MeBr). Trials were conducted in a field with naturally occurring populations of M. arenaria. Treatments were solarization alone, steam treatment after solarization using standard 7.6-cm-diameter perforated plastic drain tile (steam 1), steam treatment following solarization using custom-drilled plastic drain tile with 1.6-mm holes spaced every 3.8 cm (steam 2), and MeBr applied at 392 kg/ha 80:20 MeBr:chloropicrin. Drain tiles were buried approximately 35 cm deep with four tiles per 1.8 by 30 m plot. Steam application followed a 4-wk solarization period concluding in mid-October. All steam was generated using a Sioux propane boiler system. Plots were steamed for sufficient time to reach the target temperature of 70°C for 20 min. Solarization plastic was retained on the plots during steaming and plots were covered with a single layer of carpet padding to provide additional insulation. The floriculture crops larkspur (Delphinium elatum and Delphinium × belladonna), snapdragon (Antirrhinum majus), and sunflower (Helianthus annuus) were produced according to standard commercial practices. One month after treatment in both years of the study, soil populations of M. arenaria were lower in both steam treatments and in MeBr compared to solarization alone. At the end of the season in both years, galling on larkspur, snapdragon, and sunflowers was lower in both steam treatments than in solarization. Both steam treatments also provided control of M. arenaria in soil at the end of the season comparable to, or exceeding that provided by MeBr. Both steam treatments also reduced M. arenaria in snapdragon roots comparable to, or exceeding

  2. Responses of tomato genotypes to avirulent and Mi-virulent Meloidogyne javanica isolates occurring in Israel.

    PubMed

    Iberkleid, Ionit; Ozalvo, Rachel; Feldman, Lidia; Elbaz, Moshe; Patricia, Bucki; Horowitz, Sigal Brown

    2014-05-01

    The behavior of naturally virulent Meloidogyne isolates toward the tomato resistance gene Mi in major tomato-growing areas in Israel was studied for the first time. Virulence of seven selected isolates was confirmed over three successive generations on resistant (Mi-carrying) and susceptible (non-Mi-carrying) tomato cultivars. Diagnostic markers verified the predominance of Meloidogyne javanica among virulent isolates selected on resistant tomato cultivars or rootstocks. To better understand the determinants of nematode selection on Mi-carrying plants, reproduction of Mi-avirulent and virulent isolates Mjav1 and Mjv2, respectively, measured as eggs per gram of root, on non-Mi-carrying, heterozygous (Mi/mi) and homozygous (Mi/Mi) genotypes was evaluated. Although no reproduction of Mjav1 was observed on Mi/Mi genotypes, some reproduction was consistently observed on Mi/mi plants; reproduction of Mjv2 on the homozygous and heterozygous genotypes was similar to that on susceptible cultivars, suggesting a limited quantitative effect of the Mi gene. Histological examination of giant cells induced by Mi-virulent versus avirulent isolates confirmed the high virulence of Mjv2 on Mi/mi and Mi/Mi genotypes, allowing the formation of well-developed giant-cell systems despite the Mi gene. Analysis of the plant defense response in tomato Mi/Mi, Mi/mi, and mi/mi genotypes to both avirulent and virulent isolates was investigated by quantitative real-time polymerase chain reaction. Although the jasmonate (JA)-signaling pathway was clearly upregulated by avirulent and virulent isolates on the susceptible (not carrying Mi) and heterozygous (Mi/mi) plants, no change in signaling was observed in the homozygous (Mi/Mi) resistant line following incompatible interaction with the avirulent isolate. Thus, similar to infection promoted by the avirulent isolate on the susceptible genotype, the Mi-virulent isolate induced the JA-dependent pathway, which might promote tomato susceptibility

  3. Evaluation of Steam and Soil Solarization for Meloidogyne arenaria Control in Florida Floriculture Crops

    PubMed Central

    Kokalis-Burelle, Nancy; Rosskopf, Erin N.; Butler, David M.; Fennimore, Steven A.; Holzinger, John

    2016-01-01

    Steam and soil solarization were investigated for control of the root-knot nematode Meloidogyne arenaria in 2 yr of field trials on a commercial flower farm in Florida. The objective was to determine if preplant steam treatments in combination with solarization, or solarization alone effectively controlled nematodes compared to methyl bromide (MeBr). Trials were conducted in a field with naturally occurring populations of M. arenaria. Treatments were solarization alone, steam treatment after solarization using standard 7.6-cm-diameter perforated plastic drain tile (steam 1), steam treatment following solarization using custom-drilled plastic drain tile with 1.6-mm holes spaced every 3.8 cm (steam 2), and MeBr applied at 392 kg/ha 80:20 MeBr:chloropicrin. Drain tiles were buried approximately 35 cm deep with four tiles per 1.8 by 30 m plot. Steam application followed a 4-wk solarization period concluding in mid-October. All steam was generated using a Sioux propane boiler system. Plots were steamed for sufficient time to reach the target temperature of 70°C for 20 min. Solarization plastic was retained on the plots during steaming and plots were covered with a single layer of carpet padding to provide additional insulation. The floriculture crops larkspur (Delphinium elatum and Delphinium × belladonna), snapdragon (Antirrhinum majus), and sunflower (Helianthus annuus) were produced according to standard commercial practices. One month after treatment in both years of the study, soil populations of M. arenaria were lower in both steam treatments and in MeBr compared to solarization alone. At the end of the season in both years, galling on larkspur, snapdragon, and sunflowers was lower in both steam treatments than in solarization. Both steam treatments also provided control of M. arenaria in soil at the end of the season comparable to, or exceeding that provided by MeBr. Both steam treatments also reduced M. arenaria in snapdragon roots comparable to, or exceeding

  4. Population dynamics of Meloidogyne arenaria and Pasteuria penetrans in a long-term crop rotation study.

    PubMed

    Timper, Patricia

    2009-12-01

    The endospore-forming bacterium Pasteuria penetrans is an obligate parasite of root-knot nematodes (Meloidogyne spp.). The primary objective of this study was to determine the effect of crop sequence on abundance of P. penetrans. The experiment was conducted from 2000 to 2008 at a field site naturally infested with both the bacterium and its host Meloidogyne arenaria and included the following crop sequences: continuous peanut (Arachis hypogaea) (P-P-P) and peanut rotated with either 2 years of corn (Zea mays) (C-C-P), 1 year each of cotton (Gossypium hirsutum) and corn (Ct-C-P), or 1 year each of corn and a vegetable (V-C-P). The vegetable was a double crop of sweet corn and eggplant (Solanum melongena). A bioassay with second-stage juveniles (J2) of M. arenaria from a greenhouse (GH) population was used to estimate endospore abundance under the different crop sequences. A greater numerical increase in endospore densities was expected in the P-P-P and V-C-P sequences than in the other sequences because both peanut and eggplant are good hosts for M. arenaria. However, endospore densities, as determined by bioassay, did not substantially increase in any of the sequences during the 9-year experiment. To determine whether the nematode population had developed resistance to the resident P. penetrans, five single egg-mass (SEM) lines from the field population of M. arenaria were tested alongside the GH population for acquisition of endospores from the field soil. Four of the five SEM lines acquired 9 to 14 spores/J2 whereas the GH population and one of the SEM lines acquired 3.5 and 1.8 spores/J2, respectively. Endospore densities estimated with the four receptive SEM lines were highest in the P-P-P plots (14-20 spores/J2), intermediate in the V-C-P plots (6-7 spores/J2), and lowest in the Ct-C-P plots (< 1 spore/J2). These results indicate that the field population of M. arenaria is heterogeneous for attachment of P. penetrans endospores. Moreover, spore densities

  5. Sustainable approaches to the management of plant-parasitic nematodes and disease complexes.

    PubMed

    Westphal, Andreas

    2011-06-01

    Physical, chemical, and biological factors of soil may reduce damage caused by plant-parasitic nematodes. Suppression of plant-parasitic nematodes is particularly challenging in soils in which there are short crop sequences, sequential susceptible host crops, or infestations of multiple nematode species. In southern Indiana, a watermelon production system involving rotations with soybean and corn does not suppress Meloidogyne incognita, but several aspects of such systems can be modified to reduce nematode damage in an integrated management approach. Cash crops with resistance to M. incognita can be used to reduce population densities of M. incognita. Small grains as cover crops can be replaced by cover crops with resistance to M. incognita or by crops with biofumigation potential. Mycorrhizal fungal inoculations of potting mixes during transplanting production of watermelon seedlings may improve early crop establishment. Other approaches to nematode management utilize soil suppressiveness. One-year rotations of soybean with corn neither reduced the soil-borne complex of sudden death syndrome (SDS) nor improved soybean root health over that in soybean monoculture. Reduced tillage combined with crop rotation may reduce the activity of soil-borne pathogens in some soils. For example in a long-term trial, numbers of Heterodera glycines and severity of foliar SDS symptoms were reduced under minimum tillage. Thus, sustainable management strategies require holistic approaches that consider entire production systems rather than focus on a single crop in its year of production.

  6. Development of Meloidogyne arenaria on Peanut and Soybean under Two Temperature Cycles

    PubMed Central

    Noe, J. P.

    1991-01-01

    Florunner peanut and three soybean cultivars, Centennial, Gasoy 17, and Wright, were inoculated with 48-hour age cohorts of Meloidogyne arenari race 1 second-stage juveniles and placed in a growth chamber set to simulate early season (low temperature) and midseason (high temperature) conditions. Percentages of the initial inoculum penetrating roots 4 and 8 days after inoculation were 2-3 times higher in soybean cultivars than in peanut; 25% on susceptible soybean and 9% on peanut. Penetration and early development of M. arenaria were greater in the higher temperature environment. Penetration percentages were expressed as a function of cumulative degree-days by regression models. Development of M. arenaria 10, 20, and 30 days after inoculation was more rapid on peanut than on soybean. The resistant soybean cultivar Wright had slower development rates than did the other two soybean cultivars. Nematode growth and development were dependent on temperature. In greenhouse experiments, production of eggs by M. arenaria was more than 10 times greater on peanut than on susceptible soybean. The reproductive factor for Wright soybean was less than one, but plant growth parameters indicated that this cultivar was intolerant of M. arenavia. PMID:19283157

  7. Meloidogyne platani n. sp. (Meloidogynidae), a Root-knot Nematode Parasitizing American Sycamore

    PubMed Central

    Hirschmann, Hedwig

    1982-01-01

    Meloidogyne platani n. sp. is described and illustrated from specimens obtained from roots of American sycamore, Platanus occidentalis, in Virginia. This new species shows certain similarities with M. arenaria but differs from it by a number of distinctive characters. The perineal pattern of females is rounded with fine, wavy to zig-zag striae and raised, convoluted striae in the inner lateral line regions. The stylet of females is 16.5 μm long with large, rounded stylet knobs set off from the shaft. Males have a low head cap and smooth head region. The styler length is 22.0 μm, and the stylet knobs are rounded and set off from the shaft. Mean second-stage juvenile length is 443.0 μm, and stylet length is 12.2 μm. The head region of juveniles is not annulated, and the tail has a definite terminus. This nematode causes severe galling and reproduces well on sycamore. Other good hosts include white ash and tobacco cv. NC 95. M. platani n. sp. reproduces by mitotic parthenogenesis and has a somatic chromosome number of approximately 45 (2n). PMID:19295679

  8. Ethylene signaling pathway modulates attractiveness of host roots to the root-knot nematode Meloidogyne hapla.

    PubMed

    Fudali, Sylwia L; Wang, Congli; Williamson, Valerie M

    2013-01-01

    Infective juveniles of the root-knot nematode Meloidogyne hapla are attracted to the zone of elongation of roots where they invade the host but little is known about what directs the nematode to this region of the root. We found that Arabidopsis roots exposed to an ethylene (ET)-synthesis inhibitor attracted significantly more nematodes than control roots and that ET-overproducing mutants were less attractive. Arabidopsis seedlings with ET-insensitive mutations were generally more attractive whereas mutations resulting in constitutive signaling were less attractive. Roots of the ET-insensitive tomato mutant Never ripe (Nr) were also more attractive, indicating that ET signaling also modulated attraction of root-knot nematodes to this host. ET-insensitive mutants have longer roots due to reduced basipetal auxin transport. However, assessments of Arabidopsis mutants that differ in various aspects of the ET response suggest that components of the ET-signaling pathway directly affecting root length are not responsible for modulating root attractiveness and that other components of downstream signaling result in changes in levels of attractants or repellents for M. hapla. These signals may aid in directing this pathogen to an appropriate host and invasion site for completing its life cycle.

  9. Meloidogyne trifoliophila n. sp. (Nemata: Meloidogynidae), a Parasite of Clover from Tennessee

    PubMed Central

    Bernard, E. C.; Eisenback, J. D.

    1997-01-01

    Meloidogyne trifoliophila n. sp. is described from white clover collected at Ames Plantation, Fayette County, Tennessee. The perineal pattern is rounded, with long, smooth striae and rounded arch, and without distinct lateral lines or perivulval striae. The female stylet is 12.6-15.5 μm long, the excretory pore is level with or up to one stylet length posterior to the stylet knobs, and the vulva is subterminal. The posterior terminus is weakly protuberant. The male lateral field is composed of approximately eight repeatedly broken or forked incisures. The male stylet is 17.0-18.9 μm long, the stylet knobs are rounded and sloping, gradually merging with the shaft, and the head region consists of one large annule. Second-stage juveniles are 357-400 μm long, with a stylet length of 11.9-13.6 μm and one head annule. The tail tapers to a slender tip. This new species is similar to M. graminicola and M. triticoryzae but differs from them in perineal pattern and lateral field morphology, and numerous morphometric characters. PMID:19274133

  10. Optimum Concentrations of Trichoderma longibrachiatum and Cadusafos for Controlling Meloidogyne javanica on Zucchini Plants

    PubMed Central

    Sokhandani, Zahra; Moosavi, Mohammad Reza; Basirnia, Tahereh

    2016-01-01

    A factorial experiment was established in a completely randomized design to verify the effect of different inoculum levels of an Iranian isolate of Trichoderma longibrachiatum separately and in combination with various concentrations of cadusafos against Meloidogyne javanica in the greenhouse. Zucchini seeds were soaked for 12 hr in five densities (0, 105, 106, 107, and 108 spores/ml suspension) of the fungus prior to planting in pots containing four concentrations of cadusafos (0, 0.5, 1, and 2 mg a.i./kg soil). The data were analyzed using a custom response surface regression model and the response surface curve and contour plots were drawn. Reliability of the model was examined by comparing the result of new experimental treatments with the predicted results. The optimal levels of these two variables also were calculated. The interactive effects of concentrations of Trichoderma and cadusafos were insignificant for several responses such as the total number of eggs per gram soil, the number of intact eggs per gram soil, nematode reproduction factor, and control percent. Closeness of experimental mean values with the expected values proved the validity of the model. The optimal levels of the cadusafos concentration and Trichoderma concentration that caused the best plant growth and lowest nematode reproduction were 1.7 mg a.i./kg soil and 108 conidia/ml suspension, respectively. PMID:27168653

  11. Control of Meloidogyne chitwoodi in Potato with Fumigant and Nonfumigant Nematicides.

    PubMed

    Ingham, R E; Hamm, P B; Williams, R E; Swanson, W H

    2000-12-01

    During 1993-94, several fumigant and nonfumigant nematicides were tested alone and in combination at various rates for control of Columbia root-knot nematode (Meloidogyne chitwoodi) in potato. Ethoprop, oxamyl, or metam sodium alone did not adequately reduce tuber infection. Metam sodium plus ethoprop reduced culled tubers to 3%, and metam sodium plus 2 or 3 foliar applications of oxamyl reduced culls to

  12. Comparison of Fumigant and Nonfumigant Nematicides for control of Meloidogyne chitwoodi on Potato.

    PubMed

    Griffin, G D

    1989-10-01

    The fumigant 1,3-dichloropropene (1,3-D) effectively controlled Meloidogyne chitwoodi on Russet Burbank potato, Solanum tuberosum. There was a maximum of 4% infected and galled tubers from the 1,3-D treatment after 2,028 degree-days with a base temperature of 5 C (DD5). This compared to 66% infected and galled tubers in aldicarb at-plant treated plots. Soil temperature, as determined by DD5, and timing of chemical applications affected the nematicidal activity on M. chitwoodi (P < 0.05). Aldicarb was most effective when applied postplant (PP) during the nematode reproductive cycle. After 1,684 DD5 of growth, there were 59, 26, 22, and 6% infected and galled tubers from untreated control plots and aldicarb treatments of 2.1 g/m row at 600 DD5, 2.1 g/m row at 1,228 DD5, and 1.3 g/m row at 600 DD5 plus 2.1 g/m row at 1,228 DD5, respectively. No aldicarb treatments were effective over a growing period of 2,028 DD5; 34% of the tubers were infected and galled following the most effective aldicarb treatment (1.3 g/m row at 504 DD5 plus 2.1 g/m row at 996 DD5).

  13. Rotations of Bahiagrass and Castorbean with Peanut for the Management of Meloidogyne arenaria

    PubMed Central

    Rodríguez-Kábana, R.; Robertson, D. G.; Weaver, C. F.; Wells, L.

    1991-01-01

    The relative value of 'Hale' castorbean (Ricinus communis) and 'Pensacola' bahiagrass (Paspalum notatum) as rotational crops for the management of Meloidogyne arenaria and southern blight (Sclerotium rolfsii) in 'Florunner' peanut (Arachis hypogaea) production was studied for 3 years in a field experiment in southeast Alabama. Peanut following 2 years of castorbean (C-C-P) yielded 43% higher than monocultured peanut without nematicide. At-plant application of aldicarb (30.5 g a.i./100 m row in a 20-cm-wide band) to monocultured peanut resulted in an average 38.9% increase in yield over the 3 years of the experiment. Peanut yield following 2 years of bahiagrass (B-B-P) was 36% higher than monocultured peanut without nematicide. Aldicarb application had no effect on southern blight, but both C-C-P and B-B-P rotations reduced the incidence of the disease in peanut. Juvenile populations of M. arenaria in soil at peanut harvest time were lower in plots with C-C-P than in those with the B-B-P rotation, and both rotations resulted in lower numbers of juveniles in soil than in the untreated monocultured peanut. PMID:19283180

  14. Responses of Guava Plants to Inoculation with Arbuscular Mycorrhizal Fungi in Soil Infested with Meloidogyne enterolobii

    PubMed Central

    Campos, Maryluce Albuquerque da Silva; da Silva, Fábio Sérgio Barbosa; Yano-Melo, Adriana Mayumi; de Melo, Natoniel Franklin; Pedrosa, Elvira Maria Régis; Maia, Leonor Costa

    2013-01-01

    In the Northeast of Brazil, expansion of guava crops has been impaired by Meloidogyne enterolobii that causes root galls, leaf fall and plant death. Considering the fact that arbuscular mycorrhizal Fungi (AMF) improve plant growth giving protection against damages by plant pathogens, this work was carried out to select AMF efficient to increase production of guava seedlings and their tolerance to M. enterolobii. Seedlings of guava were inoculated with 200 spores of Gigaspora albida, Glomus etunicatum or Acaulospora longula and 55 days later with 4,000 eggs of M. enterolobii. The interactions between the AMF and M. enterolobii were assessed by measuring leaf number, aerial dry biomass, CO2 evolution and arbuscular and total mycorrhizal colonization. In general, plant growth was improved by the treatments with A. longula or with G. albida. The presence of the nematode decreased arbuscular colonization and increased general enzymatic activity. Higher dehydrogenase activity occurred with the A. longula treatment and CO2 evolution was higher in the control with the nematode. More spores and higher production of glomalin-related soil proteins were observed in the treatment with G. albida. The numbers of galls, egg masses and eggs were reduced in the presence of A. longula. Inoculation with this fungus benefitted plant growth and decreased nematode reproduction. PMID:25288951

  15. Effects of Acibenzolar-S-Methyl Application to Rotylenchulus reniformis and Meloidogyne javanica

    PubMed Central

    Chinnasri, B.; Sipes, B. S.; Schmitt, D. P.

    2003-01-01

    Effects of acibenzolar-s-methyl, an inducer of systemic acquired resistance in plants, on Rotylenchulus reniformis and Meloidogyne javanica in vitro and in vivo were determined. A single foliar application of acibenzolar at 50 mg/liter (5 ml of solution per plant) to 7-day-old cowpea or soybean seedlings decreased R. reniformis and M. javanica egg production by 50% 30 days after inoculation. The mechanism of acibenzolar on plant-parasitic nematodes was then investigated. Acibenzolar at 50 to 200 mg/liter did not affect movement of R. reniformis and M. javanica or penetration of second-stage juveniles (J2) of M. javanica on cowpea. However, M. javanica development was slowed and fecundity was reduced in plants treated with acibenzolar. On average, 50% of J2 that penetrated acibenzolar-treated cowpeas developed into mature females with eggs, whereas the other 50% exhibited arrested development. The number of eggs per egg mass was 450 in water-treated cowpeas, whereas the number declined to 250 in acibenzolar-treated plants. Acibenzolar may be responsible for stimulating the plants to express some resistance to the nematodes. PMID:19265983

  16. Fungi Parasitic on Juveniles and Egg Masses of Meloidogyne hapla in Organic Soils from New York.

    PubMed

    Viaene, N M; Abawi, G S

    1998-12-01

    Fungi associated with egg masses and juveniles of Meloidogyne hapla were isolated from organic soil samples obtained from five fields planted to lettuce or onion in NewYork. The soil samples were placed in sterilized clay pots, infested with M. hapla, and planted to lettuce. After 4 months, egg masses and juveniles were surface-disinfested, plated on water agar, and examined for fungal infection. Depending on the soil sample, fungal isolates were recovered from 13% to 30%, and from 5% to 24% of the egg masses and juveniles, respectively. A total of 24 and 16 isolates collected from egg masses and juveniles, respectively, were selected for further characterization. Fifteen of the isolates were considered as egg-mass pathogens as they were able to infect healthy assay egg masses and could be succesfully reisolated. These fungi included species of Fusarium, Alternatia, and Verticillium psalliotae. Six of the egg-mass-parasitizing fungi could not be identified. Nine fungal isolates were found to be pathogenic to juveniles of M. hapla; six were identified as Monacrosporium sp., two as Arthrobotrys sp., and one as Hirsutella rhossiliensis. The remaining 16 fungal isolates were unable to infect egg masses or juveniles, and thus were considered nonparasitic to M. hapla.

  17. Sequence and genetic map of Meloidogyne hapla: A compact nematode genome for plant parasitism

    PubMed Central

    Opperman, Charles H.; Bird, David M.; Williamson, Valerie M.; Rokhsar, Dan S.; Burke, Mark; Cohn, Jonathan; Cromer, John; Diener, Steve; Gajan, Jim; Graham, Steve; Houfek, T. D.; Liu, Qingli; Mitros, Therese; Schaff, Jennifer; Schaffer, Reenah; Scholl, Elizabeth; Sosinski, Bryon R.; Thomas, Varghese P.; Windham, Eric

    2008-01-01

    We have established Meloidogyne hapla as a tractable model plant-parasitic nematode amenable to forward and reverse genetics, and we present a complete genome sequence. At 54 Mbp, M. hapla represents not only the smallest nematode genome yet completed, but also the smallest metazoan, and defines a platform to elucidate mechanisms of parasitism by what is the largest uncontrolled group of plant pathogens worldwide. The M. hapla genome encodes significantly fewer genes than does the free-living nematode Caenorhabditis elegans (most notably through a reduction of odorant receptors and other gene families), yet it has acquired horizontally from other kingdoms numerous genes suspected to be involved in adaptations to parasitism. In some cases, amplification and tandem duplication have occurred with genes suspected of being acquired horizontally and involved in parasitism of plants. Although M. hapla and C. elegans diverged >500 million years ago, many developmental and biochemical pathways, including those for dauer formation and RNAi, are conserved. Although overall genome organization is not conserved, there are areas of microsynteny that may suggest a primary biological function in nematodes for those genes in these areas. This sequence and map represent a wealth of biological information on both the nature of nematode parasitism of plants and its evolution. PMID:18809916

  18. Plant Sources of Chinese Herbal Remedies: Effects on Pratylenchus vulnus and Meloidogyne javanica

    PubMed Central

    Ferris, H.; Zheng, L.

    1999-01-01

    More than 500 plant species, used alone or in combination, are documented in Chinese traditional medicine to have activity against helminth and micro-invertebrate pests of humans. We subjected 153 candidate medicines or their plant sources to multilevel screening for effectiveness against plant-parasitic nematodes. For extracts effective in preliminary screens, we determined time-course and concentration-response relationships. Seventy-three of the aqueous extracts of medicines or their plant sources killed either Meloidogyne javanica juveniles or Pratylenchus vulnus (mixed stages), or both, within a 24-hour exposure period. Of 64 remedies reported as antihelminthics, 36 were effective; of 21 classi- fied as purgatives, 13 killed the nematodes; of 29 indicated as generally effective against pests, 13 killed the nematodes. Sources of extracts effective against one or both species of plant-parasitic nematodes are either the whole plant or vegetative, storage or reproductive components of the plants. Effective plants include both annuals and perennials, range from grasses and herbs to woody trees, and represent 46 plant families. PMID:19270895

  19. Penetration of Crotalaria juncea, Dolichos lablab, and Sesamum indicum Roots by Meloidogyne javanica

    PubMed Central

    Araya, M.; Caswell-Chen, E. P.

    1994-01-01

    Penetration of Crotalaria juncea (PI 207657 and cv. Tropic Sun) Dolichos lablab cv. Highworth, and Sesamum indicum by juveniles (J2) of Meloidogyne javanica was assessed to investigate the mechanism by which these plants may reduce nematode numbers in the field. Growth chamber experiments were conducted at 25 C, with vials containing 90 g sand infested with 450 J2; tomato (UC 204 C) was included as a susceptible host. Fifteen days after inoculation, roots were stained and the nematodes within stained roots were counted. Both C. juncea lines were highly resistant to penetration, as they contained significantly fewer nematodes per cm of root and per root system than the other plants. Although containing more nematodes per cm of root than C. juncea, S. indicum and D. lablab had significantly fewer nematodes per root system and per cm of root than tomato. Roots were significantly longer in the plants with the lowest nematode penetration. Although C. juncea, D. lablab, and S. indicum may have potential utility as cover or rotation crops in soil infested with M. javanica, further quantitative information on the reproduction of M. javanica and other nematodes in these plants is needed. PMID:19279887

  20. Meloidogyne hapla in Organic Soil: Effects of Environment on Hatch, Movement and Root Invasion

    PubMed Central

    Wong, T. K.; Mai, W. F.

    1973-01-01

    Using new techniques, hatch and movement of Meloidogyne hapla and nematode invasion o f lettuce roots growing in organic soil were studied under controlled soil conditions of temperature, moisture, O₂ and CO₂. When O₂ levels of 2.7, 5, 10, 21 and 40% with CO₂ maintained at 0.03% were used, O₂ below 21% or at 40% reduced nematode activities compared with those at 21%. When CO₂ levels of 0.03, 0.33, 2.8, 10 and 30% with O₂ maintained at 21% were used, all levels above 0.03% CO₂ resulted in less activity than at 0.03% except for more invasion at 0.33% than at 0.03%. Results suggested M. hapla was tolerant of CO₂ below 10% but adversely affected by 30% CO₂. Effect of O₂ was influenced by the level of CO₂ present. No larvae invaded roots at 3.2% O₂ and 18.6% CO₂ but hatch and movement occurred. Night and day temperatures of 21.1 and 26.7 C were more favorable for movement and invasion than 15.5 and 21.1 C, 26.7 and 32.2 C or 26.7 and 32.2 C. Optimum moisture for movement was 80 cm suction and for invasion was 100 cm. PMID:19319318

  1. Effect of Cutting Age on the Resistance of Prunus cerasifera (Myrobalan Plum) to Meloidogyne arenaria.

    PubMed

    Esmenjaud, D; Minot, J C; Voisin, R; Salesses, G; Bonnet, A

    1995-12-01

    The response of softwood cuttings of Myrobalan plum infested after 50 and 105 days with 3,000 second-stage juveniles (J2) of Meloidogyne arenaria was compared to 15-month-old hardwood cuttings in 13 genotypes ranging from highly resistant to susceptible. Gall index and number of galls were recorded 30 days after infestation. Fifty-day-old cuttings rooted in perlite developed many rootlets, but had only incipient galls after infestation. In sand, rooting of 50-day-old cuttings not treated with indolebutyric acid (IBA) hormone was so variable that their resistance could not be assessed. Similar cuttings rooted with IBA developed more galls, but neither number of galls per plant nor gall index was a reliable criterion for determination of host suitability. Because of the better rooting results with IBA treatment, 105-day-old cuttings were first rooted with IBA in perlite and then transferred into sand for nematode inoculation. Known highly resistant genotypes of Myrobalan plum were gall-free and the responses of other genotypes paralleled that of the reference hardwood cuttings, although the test was less discriminating. Expression of M. arenaria host suitability in Myrobalan plum depends on root tissue maturation and cannot be reliably evaluated with 50-day-old cuttings.

  2. Effect of Cutting Age on the Resistance of Prunus cerasifera (Myrobalan Plum) to Meloidogyne arenaria

    PubMed Central

    Esmenjaud, D.; Minot, J. C.; Voisin, R.; Salesses, G.; Bonnet, A.

    1995-01-01

    The response of softwood cuttings of Myrobalan plum infested after 50 and 105 days with 3,000 second-stage juveniles (J2) of Meloidogyne arenaria was compared to 15-month-old hardwood cuttings in 13 genotypes ranging from highly resistant to susceptible. Gall index and number of galls were recorded 30 days after infestation. Fifty-day-old cuttings rooted in perlite developed many rootlets, but had only incipient galls after infestation. In sand, rooting of 50-day-old cuttings not treated with indolebutyric acid (IBA) hormone was so variable that their resistance could not be assessed. Similar cuttings rooted with IBA developed more galls, but neither number of galls per plant nor gall index was a reliable criterion for determination of host suitability. Because of the better rooting results with IBA treatment, 105-day-old cuttings were first rooted with IBA in perlite and then transferred into sand for nematode inoculation. Known highly resistant genotypes of Myrobalan plum were gall-free and the responses of other genotypes paralleled that of the reference hardwood cuttings, although the test was less discriminating. Expression of M. arenaria host suitability in Myrobalan plum depends on root tissue maturation and cannot be reliably evaluated with 50-day-old cuttings. PMID:19277333

  3. Resistance and host-response of selected plants to Meloidogyne megadora.

    PubMed

    de Almeida, A M S F; de A Santos, M S N

    2002-06-01

    Fourteen plant species, including 30 genotypes, were assessed for host suitability to Meloidogyne megadora in a growth room at 20 to 28 degrees C. Host suitability was based on the gall index (GI) and the reproduction factor (Rf):final population density (Pf)/initial population density (Pi). The presence of distinct galling was observed on roots of six plant species, and reproduction occurred on five of the 14 species tested. Three cultivars of cantaloupe (cvs. Branco do Ribatejo, Concerto, and Galia), three of cucumber (cvs. LM 809, Half Long Palmetto, and Market More), six of banana (cvs. Maçá, Ouro Branco, Ouro Roxo, Prata, Páo, and Valery), and one of broad bean (cv. Algarve) were considered susceptible (Pf/Pi > 1). Resistant cultivars (Pf/Pi = 0) included beet (cv, Crosby), pepper (cv. LM 204), watermelon (cvs. Black Magic and Crimson Sweet), tomato (cvs. Moneymaker and Rossol), radish (cv. Cherry Belle), and corn (cv. Dunia); sunn hemp and black velvetbean genotypes were also resistant. All Brassica cultivars were galled, although no egg masses were observed (Pf/Pi = 0), and classified as resistant/hypersensitive.

  4. Interaction of Vesicular-Arbuscular Mycorrhizae and Cultivars of Alfalfa Susceptible and Resistant to Meloidogyne hapla

    PubMed Central

    Grandison, Gordon S.; Cooper, Karen M.

    1986-01-01

    The interaction between vesicular-arbuscular mycorrhizal (VAM) fungi and the root-knot nematode (Meloidogyne hapla) was investigated using both nematode-susceptible (Grasslands Wairau) and nematode-resistant (Nevada Synthetic XX) cultivars of alfalfa (Medicago sativa) at four levels of applied phosphate. Mycorrhizal inoculation improved plant growth and reduced nematode numbers and adult development in roots in dually infected cultures of the susceptible cultivar. The tolerance of plants to nematode infection and development when preinfected with mycorrhizal fungi was no greater than when they were inoculated with nematodes and mycorrhizal fungi simultaneously. Growth of plants of the resistant cultivar was unaffected by nematode inoculation but was improved by mycorrhizal inoculation. Numbers of nematode juveniles were lower in the roots of the resistant than of the susceptible cultivar and were further reduced by mycorrhizal inoculation, although no adult nematodes developed in any resistant cultivar treatment. Inoculation of alfalfa with VAM fungi increased the tolerance and resistance of a cultivar susceptible to M. hapla and improved the resistance of a resistant cultivar. PMID:19294155

  5. Pathological Reaction of Crested Wheatgrass Cultivars to Four Meloidogyne chitwoodi Populations.

    PubMed

    Griffin, G D; Asay, K H

    1989-10-01

    Meloidogyne chitwoodi populations from Tulelake, California; Ft. Hall, Idaho; Beryl, Utah; and Prosser, Washington, significantly (P < 0.05) reduced dry shoot weights of crested wheatgrass (Agropyron cristatum L., Gaertn. and A. desertorum, Fisch. ex Link, Schult.) cultivars Hycrest, Fairway, and Nordan in experiments conducted in a greenhouse and growth chamber. Shoot growth depression, root galling, and nematode reproduction indices were greatest (P < 0.05) on plants inoculated with 5,000 eggs/plant. Nematode populations from Tulelake, Ft. Hall, and Beryl significantly (P < 0.05) reduced the growth of the three grass cultivars at 15, 20, 25, and 30 C; the greatest reductions occurred at 20 and 25 C. There were significant differences in the virulence of the nematode populations at high (30 C) and low (15 C) soil temperatures. At 15 C, plant growth was reduced more by the Beryl and Tulelake than by the Ft. Hall population; whereas at 30 C, the Ft. Hall population was more virulent than the Beryl and Tulelake populations. Root galling and nematode reproduction were greater on plants inoculated with Beryl and Tulelake populations at 15 C than on plants inoculated with the Ft. Hall population, while the Ft. Hall population had the most pronounced effects at 30 C.

  6. Multivariate statistics applied to the reaction of common bean plants to parasitism by Meloidogyne javanica.

    PubMed

    Santos, L N S; Cabral, P D S; Neves, G A R; Alves, F R; Teixeira, M B; Cunha, F N; Silva, N F

    2017-03-16

    The availability of common bean cultivars tolerant to Meloidogyne javanica is limited in Brazil. Thus, the present study aimed to evaluate the reactions of 33 common bean genotypes (23 landrace, 8 commercial, 1 susceptible standard and 1 resistant standard) to M. javanica, employing multivariate statistics to discriminate the reaction of the genotypes. The experiment was conducted in a greenhouse using a completely randomized design with seven replicates. The seeds were sown in 1-L pots containing autoclaved soil and sand in a 1:1 ratio (v:v). On day 19, after emergence of the seedlings, the plants were treated with inoculum containing 4000 eggs + second-stage juveniles (J2). At 60 days after inoculation, the seedlings were evaluated based on biometric and parasitism-related traits, such as number of galls, final nematode population per root system, reproduction factor, and percent reduction in the reproduction factor of the nematode (%RRF). The data were subjected to analysis of variance using the F-test. The Mahalanobis generalized distance was used to obtain the dissimilarity matrix, and the average linkage between groups was used for clustering. The use of multivariate statistics allowed groups to be separated according to the resistance levels of genotypes, as observed in the %RRF. The landrace genotypes FORT-09, FORT-17, FORT-31, FORT-32, FORT-34 and FORT-36 presented resistance to M. javanica; thus, these genotypes can be considered potential sources of resistance.

  7. Control of Meloidogyne javanica by Formulations of Inula viscosa Leaf Extracts

    PubMed Central

    Oka, Yuji; Ben-Daniel, Bat-Hen; Cohen, Yigal

    2006-01-01

    Inula viscosa is a perennial plant that is widely distributed in Mediterranean countries. Formulations of I. viscosa extracts were tested for their effectiveness in control of Meloidogyne javanica in laboratory, growth chamber, microplot, and field experiments. Oily pastes were obtained by extraction of dry leaves with a mixture of acetone and n-hexane or n-hexane alone, followed by evaporation of the solvents. Emulsifiable concentrate formulations of the pastes killed M. javanica juveniles in sand at a concentration of 0.01% (paste, w/w) or greater and reduced the galling index of cucumber seedlings as well as the galling index and numbers of nematode eggs on tomato plants in growth chamber experiments. In microplot experiments, the hexane-extract formulation at 26 g paste/m2 reduced nematode infection on tomato plants in one of two experiments. In a field experiment, a reduction of 40% in root galling index by one of two formulations was observed on lettuce plants. The plant extracts have potential as a natural nematicide, although the formulations need improvement. PMID:19259429

  8. Developmental Response of a Resistance-Breaking Population of Meloidogyne arenaria on Vitis spp.

    PubMed

    Anwar, Safdar A; McKenry, M V

    2002-03-01

    Pre- and post-infection resistance mechanisms expressed by Vitis rootstocks RS-9 and Teleki 5C against second-stage juveniles (J2) of resistance-breaking populations of Meloidogyne arenaria were observed and correlated with juvenile development and nematode reproduction. Cabernet Sauvignon grape was used as a susceptible control for comparison. Similar numbers of J2 penetrated Teleki 5C and Cabernet Sauvignon roots. Root-tip necrosis, a hypersensitive reaction, occurred in both rootstocks but was effective in reducing J2 penetration only in RS-9 roots. Juvenile development occurred in roots of all three rootstocks by 13 days after inoculation, with the highest number of swollen juveniles present in Cabernet Sauvignon roots. Cortical necroses restricted the ability of J2 to reach vascular bundles, thereby restricting access to successful feeding sites and leading to dead or underdeveloped juveniles in RS-9 roots. At 35 days after inoculation, only 5% and 25% of the initial inoculum in RS-9 and Teleki 5C roots, respectively, reached the adult stage compared to 32% in Cabernet roots. Giant cells were of sufficient size to support nematode development to maturity in Cabernet. Cell necrosis and underdeveloped giant cells were apparent in the resistant rootstocks, which delayed development of adults and limited egg production. Inadequate development of giant cells may provide long-term population reductions in woody-rooted perennial crops.

  9. Description of the Kona Coffee Root-knot Nematode, Meloidogyne konaensis n. sp.

    PubMed Central

    Eisenback, J. D.; Bernard, E. C.; Schmitt, D. P.

    1994-01-01

    Meloidogyne konaensis n. sp. is described from coffee from Kona on the island of Hawaii. The perineal pattern of the female is variable in morphology, the medial lips of the female are divided into distinct lip pairs, and the excretory pore is 2-3 stylet lengths from the base of the stylet. Mean stylet length is 16.0 μm, and the knobs gradually merge with the shaft. The knobs are indented anteriorly and rounded posteriorly and the dorsal esophageal gland orifice (DEGO) is long, 3.5-7 μm. The morphology of the stylet of the male is the most useful diagnostic character, with 6-12 large projections protruding from the shaft. One medial lip may be divided into distinct lip pairs. A large intestinal caecum often extends nearly to the level of the DEGO. Mean juvenile length is 502 μm, mean stylet length is 13.4 μm, and mean tail length is 58 μm. The tail may be distinctly curved ventrally and the phasmids are located in the ventral incisure about one anal body width posterior to the anus. PMID:19279905

  10. Description and SEM Observations of Meloidogyne sasseri n. sp. (Nematoda: Meloidogynidae), Parasitizing Beachgrasses

    PubMed Central

    Handoo, Zafar A.; Huettel, Robin N.; Golden, A. Morgan

    1993-01-01

    Meloidogyne sasseri n. sp. is described and illustrated from American beachgrass (Ammophila breviliffulata) originally collected from Henlopen State Park and Fenwick Island near the Maryland state line in Delaware, United States (6). Its relationship to M. graminis, M. spartinae, and M. californiensis is discussed. Primary distinctive characters of the female perineal pattern were a high to rounded arch with shoulders, widely spaced lateral lines interrupting transverse striations, a sunken vulva and anus, and coarse broken striae around the anal area. Second-stage juvenile body length was 554 μm (470-550), stylet length 14 μm (13-14.5), tail length 93 μm (83-115), tapering to a finely rounded terminus. Male stylet length 20 μm (19-21.5), spicule length 33 μm (30-36). Scanning electron microscope observations provided additional details of perineal patterns and face views of the female, male, and J2 head. Wheat, rice, oat, Ammophila sp., Panicum sp., bermudagrass, zoysiagrass and St. Augustinegrass were tested as hosts. Distribution of the species was the coasts of Delaware and Maryland. The common name "beachgrass root-knot" is proposed for M. sasseri n. sp. PMID:19279820

  11. Relationship Between Meloidogyne hapla Density and Damage to Carrots in Organic Soils

    PubMed Central

    Vrain, T. C.

    1982-01-01

    Field and growth chamber experiments were conducted to determine the effect of five initial densities (Pi - 20 - 240/100 cm³ soil) of Meloidogyne hapla on carrot development and yield of storage roots at maturity. Carrots growing in infested and noninfested organic soil were harvested after 15, 29, 44, 59, and 106 days of growth in controlled environment chambers and after l l 0 days in field plots. Nematodes affected weight of roots and foliage, weight and length of the storage portion of tap roots, and induced malformations (forking), galling, and hairiness of tap roots. In most cases the data could not be represented satisfactorily by the exponential model of Seinhorst: y = m + (l-m) ZP-t. In growth chambers the weight of mature storage roots was not correlated to initial nematode density, but there was a significant negative correlation between weight of storage roots and initial nematode density in field plots. Tolerance levels were calculated as points where the regression lines reached the growth level on noninoculated plants. The tolerance levels of foliage were higher than those of roots, and increased with age of plants. The tolerance level of marketable weight in field plots, average crop value, and a hypothetical control cost function are used to discuss the possibility of optimizing chemical control of root-knot nematode in organic soils. PMID:19295674

  12. Histopathology of Beta vulgaris to Individual and Concomitant Infections by Meloidogyne hapla and Heterodera schachtii

    PubMed Central

    Jatala, Parviz; Jensen, H. J.

    1976-01-01

    Histological changes in roots of Beta vulgaris cultivar 'USH9A' resulting from infection of Meloidogyne hapla alone, Heterodera schachtii alone, or infection by both species on one feeding site were studied. Anatomical changes caused by M. hapla infection were characterized by regions of hypertrophy and hyperplasia. Giant cells were formed within the stele and varied in numbers from 4-7/feeding site; hyperplasia occurred in the form of a large number of relatively small compacted cells generally surrounding the hypertrophied region. H. schachtii-induced syncytia became dense and muhinucleate. Syncytia were formed in the stele and were limited on the side toward the nematode by endodermis or in part by cortical tissue. Histological changes due to the presence of both parasites on one feeding site were characterized by formation of two distinctive pathological tissues typical of both nematodes. In most infections, xylem elements separated the two pathological tissues. In some sections, a single wall separated the two pathological tissues, and no dissolution of separating wall was noted in any sections. Each nematode developed normally and produced its own characteristic pathological tissue independently. PMID:19308244

  13. Optimum Concentrations of Trichoderma longibrachiatum and Cadusafos for Controlling Meloidogyne javanica on Zucchini Plants.

    PubMed

    Sokhandani, Zahra; Moosavi, Mohammad Reza; Basirnia, Tahereh

    2016-03-01

    A factorial experiment was established in a completely randomized design to verify the effect of different inoculum levels of an Iranian isolate of Trichoderma longibrachiatum separately and in combination with various concentrations of cadusafos against Meloidogyne javanica in the greenhouse. Zucchini seeds were soaked for 12 hr in five densities (0, 10(5), 10(6), 10(7), and 10(8) spores/ml suspension) of the fungus prior to planting in pots containing four concentrations of cadusafos (0, 0.5, 1, and 2 mg a.i./kg soil). The data were analyzed using a custom response surface regression model and the response surface curve and contour plots were drawn. Reliability of the model was examined by comparing the result of new experimental treatments with the predicted results. The optimal levels of these two variables also were calculated. The interactive effects of concentrations of Trichoderma and cadusafos were insignificant for several responses such as the total number of eggs per gram soil, the number of intact eggs per gram soil, nematode reproduction factor, and control percent. Closeness of experimental mean values with the expected values proved the validity of the model. The optimal levels of the cadusafos concentration and Trichoderma concentration that caused the best plant growth and lowest nematode reproduction were 1.7 mg a.i./kg soil and 10(8) conidia/ml suspension, respectively.

  14. Specific microbial attachment to root knot nematodes in suppressive soil.

    PubMed

    Adam, Mohamed; Westphal, Andreas; Hallmann, Johannes; Heuer, Holger

    2014-05-01

    Understanding the interactions of plant-parasitic nematodes with antagonistic soil microbes could provide opportunities for novel crop protection strategies. Three arable soils were investigated for their suppressiveness against the root knot nematode Meloidogyne hapla. For all three soils, M. hapla developed significantly fewer galls, egg masses, and eggs on tomato plants in unsterilized than in sterilized infested soil. Egg numbers were reduced by up to 93%. This suggested suppression by soil microbial communities. The soils significantly differed in the composition of microbial communities and in the suppressiveness to M. hapla. To identify microorganisms interacting with M. hapla in soil, second-stage juveniles (J2) baited in the test soil were cultivation independently analyzed for attached microbes. PCR-denaturing gradient gel electrophoresis of fungal ITS or 16S rRNA genes of bacteria and bacterial groups from nematode and soil samples was performed, and DNA sequences from J2-associated bands were determined. The fingerprints showed many species that were abundant on J2 but not in the surrounding soil, especially in fungal profiles. Fungi associated with J2 from all three soils were related to the genera Davidiella and Rhizophydium, while the genera Eurotium, Ganoderma, and Cylindrocarpon were specific for the most suppressive soil. Among the 20 highly abundant operational taxonomic units of bacteria specific for J2 in suppressive soil, six were closely related to infectious species such as Shigella spp., whereas the most abundant were Malikia spinosa and Rothia amarae, as determined by 16S rRNA amplicon pyrosequencing. In conclusion, a diverse microflora specifically adhered to J2 of M. hapla in soil and presumably affected female fecundity.

  15. Specific Microbial Attachment to Root Knot Nematodes in Suppressive Soil

    PubMed Central

    Adam, Mohamed; Westphal, Andreas; Hallmann, Johannes

    2014-01-01

    Understanding the interactions of plant-parasitic nematodes with antagonistic soil microbes could provide opportunities for novel crop protection strategies. Three arable soils were investigated for their suppressiveness against the root knot nematode Meloidogyne hapla. For all three soils, M. hapla developed significantly fewer galls, egg masses, and eggs on tomato plants in unsterilized than in sterilized infested soil. Egg numbers were reduced by up to 93%. This suggested suppression by soil microbial communities. The soils significantly differed in the composition of microbial communities and in the suppressiveness to M. hapla. To identify microorganisms interacting with M. hapla in soil, second-stage juveniles (J2) baited in the test soil were cultivation independently analyzed for attached microbes. PCR-denaturing gradient gel electrophoresis of fungal ITS or 16S rRNA genes of bacteria and bacterial groups from nematode and soil samples was performed, and DNA sequences from J2-associated bands were determined. The fingerprints showed many species that were abundant on J2 but not in the surrounding soil, especially in fungal profiles. Fungi associated with J2 from all three soils were related to the genera Davidiella and Rhizophydium, while the genera Eurotium, Ganoderma, and Cylindrocarpon were specific for the most suppressive soil. Among the 20 highly abundant operational taxonomic units of bacteria specific for J2 in suppressive soil, six were closely related to infectious species such as Shigella spp., whereas the most abundant were Malikia spinosa and Rothia amarae, as determined by 16S rRNA amplicon pyrosequencing. In conclusion, a diverse microflora specifically adhered to J2 of M. hapla in soil and presumably affected female fecundity. PMID:24532076

  16. Effects of the Mi-1, N and Tabasco Genes on Infection and Reproduction of Meloidogyne Mayaguensis on Tomato and Pepper Genotypes

    USDA-ARS?s Scientific Manuscript database

    Meloidogyne mayaguensis is a damaging root-knot nematode that is able to reproduce on root-knot nematode-resistant tomato and other economically important crops. In a growth chamber experiment conducted at 22 and 33 C, isolate 1 of M. mayaguensis reproduced at both temperatures on the Mi-1-carrying...

  17. Meloidogyne petuniae n. sp. (Nemata: Meloidogynidae), a Root-knot Nematode Parasitic on Petunia in Brazil

    PubMed Central

    Charchar, J. M.; Eisenback, J. D.; Hirschmann, H.

    1999-01-01

    Meloidogyne petuniae n. sp. is described and illustrated from specimens parasitic on petunia (Petunia hybrida L.) in Brasilia, Brazil. The perineal pattern of the female is elongate to ovoid with a high, squarish arch and widely spaced, coarse striae. The stylet of the female is 12.9-16.5 µm long and has three small, rounded knobs that are distinctly set off from the shaft. Each knob is marked by a deep longitudinal indentation posteriorly and anteriorly. In SEM the base of the shaft appears to be divided into six distinct ridges. The excretory pore opens about 15.4-53.6 µm from the head end. Males are approximately 0.8-2.2 mm long. Most specimens have a high and narrow head cap, but in some the head cap is narrow and low. The stylet of the male is 21.1-26.0 µm long and has small, rounded knobs, set off from the shaft, but not indented as in the female. Second-stage juveniles are 353-464 µm long; the labial disc is fused with the medial lips to form a dumbbell-shaped head cap; the medial lips are indented posteriorly; and the head region is marked with one to two irregular annulations. The stylet is 9.2-10.8 µm long and has rounded, posteriorly sloping knobs. The tail is slender, approximately 46.4-57.2 µm long, and has a short hyaline terminus, 10.3-13.5 µm long. The somatic chromosome number is 2n = 41 and the esterase phenotype is VS1-S1, with S1 being a weak band. The malate dehydrogenase phenotype is N1, which is unique for this species. Petunia, tomato, tobacco, pea, and bean are good hosts; pepper, watermelon, and sweet corn are poor hosts; and peanut, cotton, and soybean are non-hosts. Galls produced by this species are smaller on petunia than on tomato. PMID:19270879

  18. Cotton as a Rotation Crop for the Management of Meloidogyne arenaria and Sclerotium rolfsii in Peanut

    PubMed Central

    Rodríguez-Kábana, R.; Robertson, D. G.; Wells, L.; Weaver, C. F.; King, P. S.

    1991-01-01

    The value of cotton (Gossypium hirsutum cv. Deltapine 90) in rotation with peanut (Arachis hypogaea cv. Florunner) for the management of root-knot nematode (Meloidogyne arenaria) and southern blight (Sclerotium rolfsii) was studied for 6 years in a field at the Wiregrass Substation in southeast Alabama. Peanut yields following either 1 or 2 years of cotton (C-P and C-C-P, respectively) were higher than those of peanut monoculture without nematicide [P(-)]. At-plant application of aldicarb to continuous peanut [P(+)] averaged 22.1% higher yields than those for P(-) over the 6 years of the study. The use of aldicarb in cotton and peanut in the C-C-P rotations increased yields of both crops over the same rotations without the nematicide. When the nematicide was applied to both crops in the C-P rotation, peanut yields were increased in only two of the possible three years when peanut was planted. Application of aldicarb to cotton only in the C-P rotation did not improve peanut yields over those obtained with the rotation without nematicide. Juvenile populations of M. arenaria determined at peanut-harvest time were lowest in plots with cotton. Plots with C-P or C-C-P had lower populations of the nematode than those with either P(-) or P(+). The incidence of southern blight (Sclerotium rolfsii) in peanut was lower in plots with the rotations than in those with peanut monoculture. Aldicarb application had no effect on the occurrence of southern blight. PMID:19283179

  19. Control of Meloidogyne javanica and M. arenaria on kenaf and roselle with genetic resistance and nematicides.

    PubMed

    Minton, N A; Adamson, W C

    1979-01-01

    Kenaf (Hibiscus cannabinus) and roselle (H. sabdarifla) were evaluated in nematicide-treated and untreated field soil naturally infested with either Meloidogyne javanica or M. arenaria. Root-knot indices indicated that the kenaf breeding line j-l-113 had moderate resistance to M. javanica and low resistance to M. arenaria. Kenaf cv Everglades 71 was highly susceptible to both M. javanica and M. arenaria, and roselle breeding line A59-56 was highly resistant. Both nematode species reproduced on all plant entries, but more larvae were recovered from the soil in plots planted to Everglades 71 than in plots planted to j-l-l13 or A59-56. In untreated soil infested with M. javanica, dry-matter yields were greater (P = 0.05) for j-l-l13 and A59-56 than for Everglades 71. The percentages of live plants at harvest were: j-l-l13, 88; A59-56, 93; and Everglades 71, 9. Ethylene dibromide (1,2-dibromoethane) at 73.9 kg a.i./ha and DBCP (1,2-dibromo-3-chloropropane) at 17.6 kg a.i./ha increased dry-matter yields significantly for all entries planted in soil infested with M. arenaria. Carbofuran (2.3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamate) at 5.9 kg a.i./ha did not increase the dry-matter yields of any entry. None of the nematicides increased the growth of any entry significantly in soil infested with M. javanica.

  20. Influence of Rotation Crops on the Strawberry Pathogens Pratylenchus penetrans, Meloidogyne hapla, and Rhizoctonia fragariae.

    PubMed

    Lamondia, J A

    1999-12-01

    Field microplot, small plot, and greenhouse experiments were conducted to determine the effects of rotation crops on Pratylenchus penetrans, Meloidogyne hapla, and Rhizoctonia fragariae populations. Extraction of P. penetrans from roots and soil in microplots and field plots planted to rotation crops was highest for Garry oat, lowest for Triple S sorgho-sudangrass and Saia oat, and intermediate for strawberry, buckwheat, and canola. Isolation of R. fragariae from bait roots was highest for strawberry and canola after 2 years of rotation and lowest for Saia oat. Nematode extraction from roots of rotation crops in field soils was generally higher than from roots in microplots. Grasses were nonhosts of M. hapla. Strawberry, canola, and buckwheat supported root-knot populations over time, but there were no differences in nematode numbers regardless of crop after one season of strawberry growth. Garry oat, canola, and, to a lesser extent, buckwheat supported large populations of P. penetrans without visible root symptoms. Strawberry plants supported fewer nematodes due to root damage. Nematode numbers from soil were less than from roots for all crops. While there were similar trends for pathogen recovery after more than 1 year of strawberry growth following rotation, differences in pathogen density and fruit yield were not significant. In the greenhouse, P. penetrans populations in roots and soil in pots were much higher for Garry oat than for Saia oat. Total P. penetrans adult and juvenile numbers per pot ranged from 40 to 880 (mean = 365.6) for Garry oat and 0 to 40 (mean = 8.7) for Saia oat. Production of Saia oat as a rotation crop may be a means of managing strawberry nematodes and black root rot in Connecticut.

  1. Influence of Rotation Crops on the Strawberry Pathogens Pratylenchus penetrans, Meloidogyne hapla, and Rhizoctonia fragariae

    PubMed Central

    LaMondia, J. A.

    1999-01-01

    Field microplot, small plot, and greenhouse experiments were conducted to determine the effects of rotation crops on Pratylenchus penetrans, Meloidogyne hapla, and Rhizoctonia fragariae populations. Extraction of P. penetrans from roots and soil in microplots and field plots planted to rotation crops was highest for Garry oat, lowest for Triple S sorgho-sudangrass and Saia oat, and intermediate for strawberry, buckwheat, and canola. Isolation of R. fragariae from bait roots was highest for strawberry and canola after 2 years of rotation and lowest for Saia oat. Nematode extraction from roots of rotation crops in field soils was generally higher than from roots in microplots. Grasses were nonhosts of M. hapla. Strawberry, canola, and buckwheat supported root-knot populations over time, but there were no differences in nematode numbers regardless of crop after one season of strawberry growth. Garry oat, canola, and, to a lesser extent, buckwheat supported large populations of P. penetrans without visible root symptoms. Strawberry plants supported fewer nematodes due to root damage. Nematode numbers from soil were less than from roots for all crops. While there were similar trends for pathogen recovery after more than 1 year of strawberry growth following rotation, differences in pathogen density and fruit yield were not significant. In the greenhouse, P. penetrans populations in roots and soil in pots were much higher for Garry oat than for Saia oat. Total P. penetrans adult and juvenile numbers per pot ranged from 40 to 880 (mean = 365.6) for Garry oat and 0 to 40 (mean = 8.7) for Saia oat. Production of Saia oat as a rotation crop may be a means of managing strawberry nematodes and black root rot in Connecticut. PMID:19270931

  2. The Complete Mitochondrial Genome of Meloidogyne graminicola (Tylenchina): A Unique Gene Arrangement and Its Phylogenetic Implications

    PubMed Central

    Sun, Longhua; Zhuo, Kan; Lin, Borong; Wang, Honghong; Liao, Jinling

    2014-01-01

    Meloidogyne graminicola is one of the most economically important plant parasitic-nematodes (PPNs). In the present study, we determined the complete mitochondrial (mt) DNA genome sequence of this plant pathogen. Compared with other PPNs genera, this genome (19,589 bp) is only slightly smaller than that of Pratylenchus vulnus (21,656 bp). The nucleotide composition of the whole mtDNA sequence of M. graminicola is significantly biased toward A and T, with T being the most favored nucleotide and C being the least favored. The A+T content of the entire genome is 83.51%. The mt genome of M. graminicola contains 36 genes (lacking atp8) that are transcribed in the same direction. The gene arrangement of the mt genome of M. graminicola is unique. A total of 21 out of 22 tRNAs possess a DHU loop only, while tRNASer(AGN) lacks a DHU loop. The two large noncoding regions (2,031 bp and 5,063 bp) are disrupted by tRNASer(UCN). Phylogenetic analysis based on concatenated amino acid sequences of 12 protein-coding genes support the monophylies of the three orders Rhabditida, Mermithida and Trichinellida, the suborder Rhabditina and the three infraorders Spiruromorpha, Oxyuridomorpha and Ascaridomorpha, but do not support the monophylies of the two suborders Spirurina and Tylenchina, and the three infraorders Rhabditomorpha, Panagrolaimomorpha and Tylenchomorpha. The four Tylenchomorpha species including M. graminicola, P. vulnus, H. glycines and R. similis from the superfamily Tylenchoidea are placed within a well-supported monophyletic clade, but far from the other two Tylenchomorpha species B. xylophilus and B. mucronatus of Aphelenchoidea. In the clade of Tylenchoidea, M. graminicola is sister to P. vulnus, and H. glycines is sister to R. similis, which suggests root-knot nematodes has a closer relationship to Pratylenchidae nematodes than to cyst nematodes. PMID:24892428

  3. Control of Meloidogyne chitwoodi in Potato with Shank-injected Metam Sodium and other Nematicides.

    PubMed

    Ingham, R E; Hamm, P B; Baune, M; David, N L; Wade, N M

    2007-06-01

    Metam sodium (MS) is often applied to potato fields via sprinkler irrigation systems (water-run, WR) to reduce propagules of soil-borne pathogenic fungi, particularly Verticillium dahliae, to prevent yield loss from potato early dying disease. However, this procedure has not been effective for controlling quality defects in tubers caused by Columbia root-knot nematode (Meloidogyne chitwoodi). In five trials from 1996 to 2001, application of MS by soil shank injection (SH) provided better control and tuber quality than that generally obtained by WR MS, in three of five trials. Results were similar when SH MS was injected at one (41-45 cm), two (15 and 30 cm) or three (15, 30 and 45 cm) depths. In the two trials where SH metam potassium was tested, culls were reduced to 3% and 0% and were equivalent to those resulting from a similar rate in kg a.i./ha of SH MS. A shank-injected tank mix of MS plus ethoprop EC and SH MS plus in-season chemigation applications of oxamyl provided acceptable control in trials where SH MS alone was inadequate. In-furrow application of aldicarb at planting following SH MS did not appear to increase performance. Most consistent control (0-2% culled tubers in five trials) occurred when SH MS at 280 liters/ha was used together with 1,3- dichloropropene (140 liters/ha), applied simultaneously or sequentially. This was similar to combinations of 1,3-D and WR MS, but SH MS may be preferred under certain conditions.

  4. Host Suitability of 32 Common Weeds to Meloidogyne hapla in Organic Soils of Southwestern Quebec

    PubMed Central

    Bélair, G.; Benoit, D. L.

    1996-01-01

    Thirty-two weeds commonly found in the organic soils of southwestern Quebec were evaluated for host suitability to a local isolate of the northern root-knot nematode Meloidogyne hapla under greenhouse conditions. Galls were observed on the roots of 21 species. Sixteen of the 21 had a reproduction factor (Pf/Pi = final number of M. hapla eggs and juveniles per initial number of M. hapla juveniles per pot) higher than carrot (Pf/Pi = 0.37), the major host crop in this agricultural area. Tomato cv. Rutgers was also included as a susceptible host and had the highest Pf/Pi value of 13.7. Bidens cernua, B. frondosa, B. vulgata, Erysimum cheiranthoides, Eupatorium maculatum, Matricaria matricarioides, Polygonum scabrum, Thalictrum pubescens, Veronica agrestis, and Sium suave are new host records for M. hapla. Bidens cernua, B. frondosa, B. wulgata, D. carota, M. matricarioides, Pasticana sativa, P. scabrum, S. suave, and Thlaspi arvense sustained moderate to high galling by M. hapla and supported high M. hapla production (12.4 ≤ Pf/Pi ≥ 2.9). Capsella bursa-pastoris, Chrysanthemum leucanthemum, Gnaphalium uliginosum, Stellaria media, and Veronica agrestis sustained moderate galling and supported moderate M. hapla reproduction (2.8 ≤ Pf/Pi ≥ 0.5). Chenopodium album, C. glaucum, E. cheiranthoides, P. convolvulus, Portulaca oleracea, and Rorippa islandica supported low reproduction (0.25 ≤ Pf/Pi ≥ 0.02) and sustained low galling. Galling was observed on Senecio vulgaris but no eggs or juveniles; thus, S. vulgaris may be useful as a trap plant. Eupatorium maculatum, and T. pubescens harbored no distinct galling but supported low to moderate M. hapla reproduction, respectively. Amaranthus retroflexus, Ambrosia artemisiifolia, Echinochloa crusgalli, Erigeron canadensis, Oenothera parviflora, Panicum capillare, Setaria glauca, S. viridis, and Solidago canadensis were nonhosts. Our results demonstrate the importance of adequate weed control in an integrated program

  5. Effects of catechin polyphenols and preparations from the plant-parasitic nematode Heterodera glycines on protease activity and behavior in three nematode species

    USDA-ARS?s Scientific Manuscript database

    Protease activities in preparations from the plant-parasitic nematodes Heterodera glycines and Meloidogyne incognita and the free-living nematode Panagrellus redivivus were inhibited by exposure to a series of 8 catechin polyphenol analogs, (+)-catechin, (-)- epicatechin (EC), (-)-gallocatechin (GC)...

  6. Detection of plant-parasitic nematode DNA in the gut of predatory and omnivorous nematodes

    USDA-ARS?s Scientific Manuscript database

    A protocol for molecular gut analysis of nematodes was developed to determine if predatory and omnivorous nematodes from five different guilds prey on Rotylenchulus reniformis, Meloidogyne incognita, and Radopholus similis. Mononchoides, Mononchus, Neoactinolaimus, Mesodorylaimus, and Aporcelaimell...

  7. Accomplishments of a 10-year initiative to develop host plant resistance to root-knot and reniform nematodes in cotton

    USDA-ARS?s Scientific Manuscript database

    In 2003 Cotton Incorporated initiated a Beltwide research program to develop host plant resistance against root-knot (Meloidogyne incognita) and reniform (Rotylenchulus reniformis) nematodes. Objectives formulated at a coordinating meeting in 2003 that included participants from public institutions...

  8. Phenotypic and molecular evaluation of cotton hairy roots as a model system for studying nematode resistance

    USDA-ARS?s Scientific Manuscript database

    The cellular mechanisms that mediate resistance of allotetraploid cotton (Gossypium spp.) to root-knot nematode (Meloidogyne incognita) and reniform nematode (Rotylenchulus reniformis) are poorly understood. Here, Agrobacterium rhizogenes-induced hairy roots were investigated as a possible research...

  9. High and Low Throughput Screens with Root-knot Nematodes Meloidogyne spp.

    PubMed Central

    Atamian, Hagop S.; Roberts, Philip A.; Kaloshian, Isgouhi

    2012-01-01

    Root-knot nematodes (genus Meloidogyne) are obligate plant parasites. They are extremely polyphagous and considered one of the most economically important plant parasitic nematodes. The microscopic second-stage juvenile (J2), molted once in the egg, is the infective stage. The J2s hatch from the eggs, move freely in the soil within a film of water, and locate root tips of suitable plant species. After penetrating the plant root, they migrate towards the vascular cylinder where they establish a feeding site and initiate feeding using their stylets. The multicellular feeding site is comprised of several enlarged multinuclear cells called 'giant cells' which are formed from cells that underwent karyokinesis (repeated mitosis) without cytokinesis. Neighboring pericycle cells divide and enlarge in size giving rise to a typical gall or root knot, the characteristic symptom of root-knot nematode infection. Once feeding is initiated, J2s become sedentary and undergo three additional molts to become adults. The adult female lays 150-250 eggs in a gelatinous matrix on or below the surface of the root. From the eggs new infective J2s hatch and start a new cycle. The root-knot nematode life cycle is completed in 4-6 weeks at 26-28°C. Here we present the traditional protocol to infect plants, grown in pots, with root-knot nematodes and two methods for high-throughput assays. The first high-throughput method is used for plants with small seeds such as tomato while the second is for plants with large seeds such as cowpea and common bean. Large seeds support extended seedling growth with minimal nutrient supplement. The first high throughput assay utilizes seedlings grown in sand in trays while in the second assay plants are grown in pouches in the absence of soil. The seedling growth pouch is made of a 15.5 x 12.5cm paper wick, folded at the top to form a 2-cm-deep trough in which the seed or seedling is placed. The paper wick is contained inside a transparent plastic pouch

  10. High and low throughput screens with root-knot nematodes Meloidogyne spp.

    PubMed

    Atamian, Hagop S; Roberts, Philip A; Kaloshian, Isgouhi

    2012-03-12

    Root-knot nematodes (genus Meloidogyne) are obligate plant parasites. They are extremely polyphagous and considered one of the most economically important plant parasitic nematodes. The microscopic second-stage juvenile (J2), molted once in the egg, is the infective stage. The J2s hatch from the eggs, move freely in the soil within a film of water, and locate root tips of suitable plant species. After penetrating the plant root, they migrate towards the vascular cylinder where they establish a feeding site and initiate feeding using their stylets. The multicellular feeding site is comprised of several enlarged multinuclear cells called 'giant cells' which are formed from cells that underwent karyokinesis (repeated mitosis) without cytokinesis. Neighboring pericycle cells divide and enlarge in size giving rise to a typical gall or root knot, the characteristic symptom of root-knot nematode infection. Once feeding is initiated, J2s become sedentary and undergo three additional molts to become adults. The adult female lays 150-250 eggs in a gelatinous matrix on or below the surface of the root. From the eggs new infective J2s hatch and start a new cycle. The root-knot nematode life cycle is completed in 4-6 weeks at 26-28°C. Here we present the traditional protocol to infect plants, grown in pots, with root-knot nematodes and two methods for high-throughput assays. The first high-throughput method is used for plants with small seeds such as tomato while the second is for plants with large seeds such as cowpea and common bean. Large seeds support extended seedling growth with minimal nutrient supplement. The first high throughput assay utilizes seedlings grown in sand in trays while in the second assay plants are grown in pouches in the absence of soil. The seedling growth pouch is made of a 15.5 x 12.5cm paper wick, folded at the top to form a 2-cm-deep trough in which the seed or seedling is placed. The paper wick is contained inside a transparent plastic pouch

  11. Inheritance of resistance to the root-knot nematode Meloidogyne arenaria in Myrobalan plum.

    PubMed

    Esmenjaud, D; Minot, J C; Voisin, R; Bonnet, A; Salesses, G

    1996-05-01

    The inheritance of resistance of the self-incompatible Myrobalan plum Prunus cerasifera to the root-knot nematode Meloidogyne arenaria was studied using first a diallel cross between five parents of variable host suitability (including two highly resistant clones P.1079 and P.2175, a moderate host P.2032, a good host P.2646 and an excellent host P.16.5), followed by the G2 crosses P.16.5 × (P.2646 × P.1079) and P.2646 × (P.16.5 × P.1079). A total of 355 G1 and 72 G2 clones obtained from hard-wood cuttings sampled from trees in the field experimental design, then rooted in the nursery and inoculated individually in containers (5-10 replicates per clone) under greenhouse conditions, were evaluated for their host suitability based on a 0-5 gall-index rating under a high and durable inoculum pressure of the nematode. In the crosses involving the resistant P.1079 and P.2175 and the hosts P.2646 and P.16.5: (1) all of the G1 crosses of P.1079 were resistant while the G2 crosses segregated 1 resistant to 1 host, (2) the G1 crosses between P.2175 and either P.2646 or P.16.5 segregated 1 resistant to 1 host, and (3) all of the G1 progeny between P.2646 and P.16.5 were host. These results indicate that resistance is conferred by a single major dominant resistance gene (homozygous) in P.1079, and the same, or an allelic or a different, major dominant gene (heterozygous) in P.2175, and that P.2646 and P.16.5 are recessive for this (these) major resistance gene(s). As expected according to the hypothesis of a recessive genotype for P.2032, all of its hybrids with P.1079 were resistant, all of its hybrids with P.2646 and P.16.5 were host, and its hybrids with P.2175 segregated for resistance. Nevertheless, the 3∶2 segregation ratio of these latter hybrids suggests that clones bearing the P.2175 gene would have a selective advantage. Both resistance genes are completely dominant and confer a non-host behaviour that totally prevents the multiplication of the nematode. This

  12. Predisposition of Broadleaf Tobacco to Fusarium Wilt by Early Infection with Globodera tabacum tabacum or Meloidogyne hapla

    PubMed Central

    LaMondia, J. A.

    1992-01-01

    In greenhouse experiments, broadleaf tobacco plants were inoculated with tobacco cyst (Globodera tabacum tabacum) or root-knot (Meloidogyne hapla) nematodes 3, 2, or 1 week before or at the same time as Fusarium oxysporum. Plants infected with nematodes prior to fungal inoculation had greater Fusarium wilt incidence and severity than those simultaneously inoculated. G. t. tabacum increased wilt incidence and severity more than did M. hapla. Mechanical root wounding within 1 week of F. oxysporum inoculation increased wilt severity. In field experiments, early-season G. t. tabacum control by preplant soil application of oxamyl indirectly limited the incidence and severity of wilt. Wilt incidence was 48%, 23%, and 8% in 1989 and 64%, 60%, and 19% in 1990 for 0.0, 2.2, and 6.7 kg oxamyl/ha, respectively. Early infection of tobacco by G. t. tabacum predisposed broadleaf tobacco to wilt by F. oxysporum. PMID:19283018

  13. A New Root-Knot Nematode Parasitizing Sea Rocket from Spanish Mediterranean Coastal Dunes: Meloidogyne dunensis n. sp. (Nematoda: Meloidogynidae)

    PubMed Central

    Palomares Rius, J. E.; Vovlas, N.; Troccoli, A.; Liébanas, G.; Landa, B. B.; Castillo, P.

    2007-01-01

    High infection rates of European sea rocket feeder roots by an unknown root-knot nematode were found in a coastal dune soil at Cullera (Valencia) in central eastern Spain. Morphometry, esterase and malate dehydrogenase electrophoretic phenotypes and phylogenetic trees demonstrated that this nematode species differs clearly from other previously described root-knot nematodes. Studies of host-parasite relationships showed a typical susceptible reaction in naturally infected European sea rocket plants and in artificially inoculated tomato (cv. Roma) and chickpea (cv. UC 27) plants. The species is herein described and illustrated and named as Meloidogyne dunensis n. sp. The new root-knot nematode can be distinguished from other Meloidogyne spp. by: (i) perineal pattern rounded-oval, formed of numerous fine dorsal and ventral cuticle striae and ridges, lateral fields clearly visible; (ii) female excretory pore at the level of stylet knobs, EP/ST ratio 1.6; (iii) second-stage juveniles with hemizonid located 1 to 2 annuli anteriorly to excretory pore and long, narrow, tapering tail; and (iv) males with lateral fields composed of four incisures anteriorly and posteriorly, while six distinct incisures are observed for large part at mid-body. Phylogenetic trees derived from distance and maximum parsimony analyses based on 18S, ITS1–5.8S-ITS2 and D2-D3 of 28S rDNA showed that M. dunensis n. sp. can be differentiated from all described root-knot nematode species, and it is clearly separated from other species with resemblance in morphology, such as M. duytsi, M. maritima, M. mayaguensis and M. minor. PMID:19259488

  14. Crosses prior to parthenogenesis explain the current genetic diversity of tropical plant-parasitic Meloidogyne species (Nematoda: Tylenchida).

    PubMed

    Fargette, Mireille; Berthier, Karine; Richaud, Myriam; Lollier, Virginie; Franck, Pierre; Hernandez, Adan; Frutos, Roger

    2010-08-01

    The tropical and subtropical parthenogenetic plant-parasitic nematodes Meloidogyne are polyphagous major agricultural pests. Implementing proper pest management approaches requires a good understanding of mechanisms, population structure, evolutionary patterns and species identification. A comparative analysis of the mitochondrial vs nuclear diversity was conducted on a selected set of Meloidogyne lines from various geographic origins. Mitochondrial co2-16S sequences and AFLP markers of total DNA were applied because of their ability to evidence discrete genetic variation between closely related isolates. Several distinct maternal lineages were present, now associated with different genetic backgrounds. Relative discordances were found when comparing mitochondrial and nuclear diversity patterns. These patterns are most likely related to crosses within one ancestral genetic pool, followed by the establishment of parthenogenesis. In this case, they mirror the genetic backgrounds of the original individuals. Another aspect could be that species emergence was recent or on process from this original genetic pool and that the relatively short time elapsed since then and before parthenogenesis settlement did not allow for lineage sorting. This could also be compatible with the hypothesis of hybrids between closely related species. This genetic pool would correspond to a species as defined by the species interbreeding concept, but also including the grey area of species boundaries. This complex process has implications on the way genotypic and phenotypic diversity should be addressed. The phenotype of parthenogenetic lines is at least for part determined by the ancestral amphimictic genetic background. A direct consequence is, therefore, in terms of risk management, the limited confidence one can have on the direct association of an agronomic threat to a simple typing or species delineation. Risk management strategies and tools must thus consider this complexity when

  15. Dexamethasone suppression test

    MedlinePlus

    DST; ACTH suppression test; Cortisol suppression test ... During this test, you will receive dexamethasone. This is a strong man-made (synthetic) glucocorticoid medication. Afterward, your blood is drawn ...

  16. Bacterial antagonists of fungal pathogens also control root-knot nematodes by induced systemic resistance of tomato plants.

    PubMed

    Adam, Mohamed; Heuer, Holger; Hallmann, Johannes

    2014-01-01

    The potential of bacterial antagonists of fungal pathogens to control the root-knot nematode Meloidogyne incognita was investigated under greenhouse conditions. Treatment of tomato seeds with several strains significantly reduced the numbers of galls and egg masses compared with the untreated control. Best performed Bacillus subtilis isolates Sb4-23, Mc5-Re2, and Mc2-Re2, which were further studied for their mode of action with regard to direct effects by bacterial metabolites or repellents, and plant mediated effects. Drenching of soil with culture supernatants significantly reduced the number of egg masses produced by M. incognita on tomato by up to 62% compared to the control without culture supernatant. Repellence of juveniles by the antagonists was shown in a linked twin-pot set-up, where a majority of juveniles penetrated roots on the side without inoculated antagonists. All tested biocontrol strains induced systemic resistance against M. incognita in tomato, as revealed in a split-root system where the bacteria and the nematodes were inoculated at spatially separated roots of the same plant. This reduced the production of egg masses by up to 51%, while inoculation of bacteria and nematodes in the same pot had only a minor additive effect on suppression of M. incognita compared to induced systemic resistance alone. Therefore, the plant mediated effect was the major reason for antagonism rather than direct mechanisms. In conclusion, the bacteria known for their antagonistic potential against fungal pathogens also suppressed M. incognita. Such "multi-purpose" bacteria might provide new options for control strategies, especially with respect to nematode-fungus disease complexes that cause synergistic yield losses.

  17. Nematode suppression and growth stimulation in corn plants (Zea mays L.) irrigated with domestic effluent.

    PubMed

    Barros, Kenia Kelly; do Nascimento, Clístenes Williams Araújo; Florencio, Lourdinha

    2012-01-01

    Treated wastewater has great potential for agricultural use due to its concentrations of nutrients and organic matter, which are capable of improving soil characteristics. Additionally, effluents can induce suppression of plant diseases caused by soil pathogens. This study evaluates the effect of irrigation with effluent in a UASB reactor on maize (Zea mays L.) development and on suppression of the diseases caused by nematodes of the genus Meloidogyne. Twelve lysimeters of 1 m(3) each were arranged in a completely randomized design, with four treatments and three replicates. The following treatments were used: T1 (W+I), irrigation with water and infestation with nematodes; T2 (W+I+NPK), irrigation with water, infestation with nematodes and fertilization with nitrogen (N), phosphorus (P) and potassium (K); T3 (E+I), irrigation with effluent and infestation with nematodes; and T4 (E+I+P), irrigation with effluent, infestation with nematodes and fertilization with phosphorus. The plants irrigated with the effluent plus the phosphorus fertilizer had better growth and productivity and were more resistant to the disease symptoms caused by the nematodes. The suppression levels may have been due to the higher levels of Zn and NO(3)(-) found in the leaf tissue of the plants irrigated with the effluent and phosphorus fertilizer.

  18. Managing root-knot nematodes: A case for cover crops in establishing peach orchards

    USDA-ARS?s Scientific Manuscript database

    Root-knot nematodes (Meloidogyne spp.) are an important pathogen of peach in the United States. Several Meloidogyne spp. have been reported to cause damage to stone fruits, but M. incognita and M. javanica are the predominant species on peach. Preplant fumigant nematicides have traditionally been ...

  19. Crop Rotation and Herbicide Effects on Population Densities of Plant-Parasitic Nematodes

    PubMed Central

    Johnson, A. W.; Dowler, C. C.; Hauser, E. W.

    1975-01-01

    The influence of herbicides and mono- and multicropping sequences on population densities of nematode species common in corn, cotton, peanut, and soybean fields in the southeastern United States was studied for 4 years. Each experimental plot was sampled at monthly intervals. The application of herbicides did not significantly affect nematode population densities. Meloidogyne incognita and Trichodorus christiei increased rapidly on corn and cotton, but were suppressed by peanut and soybean. More Pratylenchus spp. occurred on corn and soybean than on cotton and peanut. Criconemoides ornatus increased rapidly on corn and peanut, but was suppressed by cotton and soybean. Helicotylenchus dihystera was more numerous on cotton and soybean than on corn and peanut. Numbers of Xiphinema americanum remained low on all crops. The peanut sequence was the most effective monocrop system for suppressing most nematode species. Multi-crop systems, corn-peanut-cotton-soybean and cotton-soybean-corn-peanut, were equally effective in suppressing nematode densities. PMID:19308149

  20. Fire Suppression and Response

    NASA Technical Reports Server (NTRS)

    Ruff, Gary A.

    2004-01-01

    This report is concerned with the following topics regarding fire suppression:What is the relative effectiveness of candidate suppressants to extinguish a representative fire in reduced gravity, including high-O2 mole fraction, low -pressure environments? What are the relative advantages and disadvantages of physically acting and chemically-acting agents in spacecraft fire suppression? What are the O2 mole fraction and absolute pressure below which a fire cannot exist? What effect does gas-phase radiation play in the overall fire and post-fire environments? Are the candidate suppressants effective to extinguish fires on practical solid fuels? What is required to suppress non-flaming fires (smoldering and deep seated fires) in reduced gravity? How can idealized space experiment results be applied to a practical fire scenario? What is the optimal agent deployment strategy for space fire suppression?