Showing papers on "Meloidogyne incognita published in 1997"
TL;DR: A modified rice cystatin, Oc-I delta D86, expressed as a transgene in Arabidopsis thaliana, has a profound effect on the size and fecundity of females for both Heterodera schachtii (beet-cyst nematodes) and Meloidogyne incognita (root-knot nematode).
Abstract: Plant nematodes are major pests of agriculture. Transgenic plant technology has been developed based on the use of proteinase inhibitors as nematode anti-feedants. The approach offers prospects for novel plant resistance and reduced use of environmentally damaging nematicides. A modified rice cystatin, Oc-I delta D86, expressed as a transgene in Arabidopsis thaliana, has a profound effect on the size and fecundity of females for both Heterodera schachtii (beet-cyst nematode) and Meloidogyne incognita (root-knot nematode). No females of either species achieved the minimum size they require for egg production. Ingestion of Oc-I delta D86 from the plant was correlated with loss of cysteine proteinase activity in the intestine thereby suppressing normal growth, as required of an effective antifeedant plant defence.
206 citations
TL;DR: In the quest for plant regulatory sequences capable of driving nematode-triggered effector gene expression in feeding structures, a large collection of transgenic Arabidopsis plants was generated as discussed by the authors.
Abstract: In the quest for plant regulatory sequences capable of driving nematode-triggered effector gene expression in feeding structures, we show that promoter tagging is a valuable tool. A large collection of transgenic Arabidopsis plants was generated. They were transformed with a beta-glucuronidase gene functioning as a promoter tag. Three T-DNA constructs, pGV1047, p delta gusBin19, and pMOG553, were used. Early responses to nematode invasion were of primary interest. Six lines exhibiting beta-glucuronidase activity in syncytia induced by the beet cyst nematode were studied. Reporter gene activation was also identified in galls induced by root knot and ectoparasitic nematodes. Time-course studies revealed that all six tags were differentially activated during the development of the feeding structure. T-DNA-flanking regions responsible for the observed responses after nematode infection were isolated and characterized for promoter activity.
109 citations
TL;DR: Responsibility to mycorrhizae was as effective as with an optimum P fertilization in promoting plant development for most growth parameters and suppression of nematode reproduction and galling during the early stages of plant development.
Abstract: The effects of the interaction between the arbuscular mycorrhizal fungus Glomus mosseae and the root-knot nematode Meloidogyne incognita on growth and nutrition of micropropagated ‘;Grand Naine’ banana (Musa AAA) cultivar was studied under greenhouse conditions. Inoculation with two G. mosseae isolates significantly increased growth of plants in relation to non-mycorrhizal plants. Response to mycorrhizae was as effective as with an optimum P fertilization in promoting plant development for most growth parameters. Meloidogyne incognita had no apparent effect on the percentage of root colonization in mycorrhizal plants. In contrast, G. mosseae suppressed root galling and nematode buildup in the roots. The percentage of mycorrhizal colonization was high (over 80%) in low P fertilized plants, but optimum P rates for bananas (four times higher than low P) significantly reduced mycorrhizal colonization. Most elements were within sufficiency levels for banana with exception of N which was low for all treatments. Mycorrhizal plants fertilized with a low P rate showed higher N, P, K, Ca, and Mg contents as compared to non-mycorrhizal plants low in P with or without the nematode. Inoculation with G. mosseae favours growth of banana plants by enhancing plant nutrition and by suppressing nematode reproduction and galling during the early stages of plant development.
107 citations
Journal Article•
TL;DR: 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.
Abstract: 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.
55 citations
Journal Article•
TL;DR: Two different genetic systems of RKN resistance were found in the subgenus Amygdalus: one system acting against M. arenaria and M. incognita but susceptible to M. javanica and the Florida isolate, and a complete genetic system for resistance also acting against the Florida isolates.
Abstract: Responses of 17 Prunus rootstocks or accessions (11 from the subgenus Amygdalus and 6 from the subgenus Prunophora) were evaluated against 11 isolates of Meloidogyne spp. including one M. arenaria, four M. incognita, four M. javanica, one M. hispanica, and an unclassified population from Florida. Characterization of plant response to root-knot nematodes was based on a gall index rating. Numbers of females and juveniles plus eggs in the roots were determined for 10 of the rootstocks evaluated against one M. arenaria, one M. incognita, one M. javanica, and the Florida isolate. These 10 rootstocks plus Nemaguard and Nemared were retested by growing three different rootstock genotypes together in containers of soil infested individually with each of the above four isolates. Garfi and Garrigues almonds, GF.305 and Rutgers Red Leaf peaches, and the peach-almond GF.677 were susceptible to all isolates. Differences in resistance were detected among the other rootstocks of the subgenus Amygdalus. The peach-almond GF.557 and Summergrand peach were resistant to M. arenaria and M. incognita but susceptible to M. javanica and the Florida isolate. Nemaguard, Nemared, and its two hybrids G x N no. 15 and G x N no. 22 were resistant to all but the Florida isolate. In the subgenus Prunophora, Myrobalan plums P.1079, P.2175, P.2980, and P.2984; Marianna plum 29C; and P. insititia plum AD.101 were resistant to all isolates. Thus, two different genetic systems of RKN resistance were found in the subgenus Amygdalus: one system acting against M. arenaria and M. incognita, and another system also acting against M. javanica. Prunophora rootstocks bear a complete genetic system for resistance also acting against the Florida isolate. The hypotheses on the relationships between these systems and the corresponding putative genes of resistance are presented. Key words: Amygdalus, Meloidogyne arenaria, Meloidogyne incognita, Meloidogyne javanica, Prunophora, Prunus amygdalus, Prunus cerasifera, Prunus persica, resistance.
54 citations
Journal Article•
TL;DR: Results showed that NemX is as resistant to M. incognita as the four breeding lines, and much more resistant than the tested susceptible cultivars of cotton.
Abstract: The level of resistance to root-knot nematode, Meloidogyne incognita, in NemX, a new cultivar of the Acala-type upland cotton, was evaluated in relation to four resistant breeding lines (N6072, N8577, N901, and N903) and four susceptible cultivars (Maxxa, SJ2, Royale, and Prema). In growth pouch tests, an average of only 4 nematode egg masses was produced on roots of NemX or the resistant lines, compared to a significantly higher average of 21 on the susceptible cultivars. In pot tests, the nematode reproduction factor (RF = Pf/Pi) in NemX and the resistant lines averaged 0.7, compared to a significantly higher average of 10 on the susceptible cultivars. Root galling in NemX or other resistant cotton averaged 15%, compared to 74% on the susceptible cultivars, in either pot or field tests. In plots with low levels of nematode infestation (Pi ≤ 150 second-stage juveniles [J2]/500 g soil), lint yield of NemX averaged 1,370 kg/ha and was less than the yield of susceptible Maxxa (1,450 k g /h a ). However, in plots with medium or high levels of nematode infestation (Pi = 151-300 or >300 J2/500 g soil, respectively), yields of NemX decreased only slightly and averaged 1,300 or 1,050 kg/ha, respectively, whereas yields of Maxxa were severely reduced to 590 or 503 kg/ha, respectively. Fusarium wih symptoms were observed on both NemX and Maxxa, and percent occurrence increased with increasing preplant nematode density. In plots with the highest nematode densities, 22% of NemX and 65% of Maxxa plants were wilted. NemX was highly effective against five M. incognita isolates and moderately effective against a sixth isolate that had been exposed to resistant cotton over several seasons. These results showed that NemX is as resistant to M. incognita as the four breeding lines, and much more resistant than the tested susceptible cultivars of cotton.
48 citations
Journal Article•
TL;DR: 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.
Abstract: 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. Key words: cotton, Gossypium hirsutum, Meloidogyne incognita, reniform nematode, resistance, root-knot nematode, Rotylenchulus reniformis, tolerance.
44 citations
Journal Article•
TL;DR: Composted amendments and soil fumigation with methyl bromide/chloropicrin on plant-parasitic nematodes were examined in a three-year split-plot field experiment on tomato in southwest Florida.
Abstract: The effects of composted amendments and soil fumigation with methyl bromide/chloropicrin on plant-parasitic nematodes were examined in a three-year split-plot field experiment on tomato (Lycopersicon esculentum) in southwest Florida. Composted amendments included municipal solid waste, yard waste, and/or biosolids. Population densities of Meloidogyne incognita and root galling on tomato from this nematode were decreased (P 0.05) by soil fumigation, but increased (P 0.10) in response to compost amendment, with maximum levels in non-fumigated, compost-amended plots. Population densities of Criconemoides spp. and Hemicycliophora spp. were reduced by fumigation. Application of compost reduced population densities of Hemicycliophora spp. but did not affect Criconemoides spp. Numbers of Paratrichodorus minor were not affected by either treatment. Amendment with municipal solid waste compost was not an effective alternative to methyl bromide fumigation for management of the root-knot nema
43 citations
TL;DR: The conformation of any particular epitope recognized by a Mab may be important in determining to which nematode a particular spore will attach, which will in turn determine its virulence on a particular nematodes.
Abstract: Antigens recognized by monoclonal antibodies (Mabs) raised to the surface of the obligate nematode hyperparasite Pasteuria penetrans were characterized. Using the attachment of spores of the bacterium to host nematodes to determine the biological variability present on the spore surface greatly underestimated the amount of surface heterogeneity present compared with estimates from immunological techniques. This heterogeneity differed not only between different individual spores from the same population but also between different spore populations. None of the Mabs completely inhibited any spore population from attaching to the nematode cuticle, suggesting that the mechanism of attachment may be more complex than previously supposed. Chemical degradation of one particular epitope recognized by monoclonal antibody PP1/117, and designated ep117, occurred after treatment with NaOH, periodate or Proteinase K, suggesting that an O-linked glycoprotein may be involved. Fibronectin, which had been found to bind to Pasteuria spores through hydrophobic interactions, also prohibited the Mab from recognizing ep117. However, SDS-PAGE of spore extracts followed by immunoblotting showed that none of the Mabs could detect this epitope and so ep117 may be conformational in nature. Thus, the conformation of any particular epitope recognized by a Mab may be important in determining to which nematode a particular spore will attach. The distribution of a particular epitope within a population of spores will in turn therefore determine its virulence on a particular nematode.
43 citations
TL;DR: Investigation in tomato plants infected or noninfected with root-knot nematode, Meloidogyne incognita in clay pots found 40% fly ash as the most economic level, enhancing yield of infected plants by 96% and suppressing the nematodes disease and reproduction by 63 and 76%, respectively.
Abstract: The effects of fly ash at different concentrations (0, 10, 20, 30 ... 100% vol./vol.in soil) on plant growth and yield were investigated in tomato plants infected or noninfected with root-knot nematode, Meloidogyne incognita (2000 juveniles per plant) in clay pots. An increase in fly ash concentration in the soil correspondingly increased the availability of carbonates, bicarbonates, sulphate, chlorides, B, P, K, Ca, Mg, Mn, Cu and Zn in the soil. The porosity, water-holding capacity, pH, conductivity and cation exchange capacity also increased progressively in the fly ash amended soil. Ash application enhanced plant growth, leaf pigment concentrations, fruit production, weight of fruit/plant and mean fruit weight of both nematode-infected and noninfected tomato plants, being maximum in the soil containing 50 or 60% fly ash. The yield enhancements were 93.6 (infected plants) and 84% (noninfected plants) at 50 and 60% fly ash levels, respectively. Fly ash treatments adversely affected root invasion by juveniles, disease intensity and reproduction of the nematodes. A gradual increase in the ash concentration in soil caused a corresponding decrease in the numbers of invading juveniles, galls and egg masses per root system and eggs/egg mass, being lowest at 100% fly ash i.e. 52, 16, 10 and 81 against 289, 137, 131 and 238 (control), respectively. Linear regression suggested 40% fly ash as the most economic level, enhancing yield of infected plants by 96% and suppressing the nematode disease and reproduction by 63 and 76%, respectively.
43 citations
Journal Article•
TL;DR: Tannins, which are water-soluble polyphenols, are toxic to numerous fungi, bacteria, and yeasts and their effects on the behavior of M. arenaria, M. incognita, Heterodera glycines, and Radopholus similis were studied.
Abstract: 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.
TL;DR: Inoculation with G. intraradices significantly increased growth of plants in relation to nonmycorrhizal plants and was more effective than P fertilization in promoting plant development and appears to favor growth of banana plants by enhancing plant nutrition.
Abstract: The effects of the interaction between the vesicular-arbuscular mycorrhizal fungus Glomus intraradices Schenk and Smith and the root-knot nematode Meloidogyne javanica (Treub) Chitwood on growth and nutrition of micropropagated 'Grand Naine' banana (Musa AAA) were studied under greenhouse conditions. Inoculation with G. intraradices significantly increased growth of plants in relation to nonmycorrhizal plants and was more effective than P fertilization in promoting plant development. Mycorrhizal colonization did not affect nematode buildup in the roots, although plants with the nematode and mycorrhiza were more galled. Meloidogyne javanica had no effect on the percentage of root colonization in mycorrhiza-inoculated plants. No element deficiency was detected by foliar analysis. All elements were within sufficiency levels for banana with exception of N, which was low. Potassium levels were lower in mycorrhizal plants, while Ca and Mg levels were higher with mycorrhiza than without, with or without the nematode. Early inoculation with G. intraradices appears to favor growth of banana plants by enhancing plant nutrition.
TL;DR: The physiological time of appearance of first foliar symptoms of Fusarium wilt, based on a degree-days threshold, was used as a basis for determining disease progress curves and the phenology of cotton plant growth and development.
Abstract: Development of Fusarium wilt in upland cotton (Gossypium hirsutum) usually requires infections of plants by both Meloidogyne incognita and Fusarium oxysporum f. sp. vasinfectum. In this study, the soil densities of M. incognita and F. oxysporum f. sp. vasinfectum and the incidence of Fusarium wilt in three field sites were determined in 1982-1984. Multiple regression analysis of percent incidence of Fusarium wilt symptoms on population densities of M. incognita and F. oxysporum f. sp. vasinfectum yielded a significant fit (R 2 = 0.64) only on F. oxysporum f. sp. vasinfectum. Significant t-values for slope were also obtained for the interaction of M. incognita and F. oxysporum f. sp. vasinfectum, but densities of M. incognita and F. oxysporum f. sp. vasinfectum were also related on a log10 scale. The physiological time of appearance of first foliar symptoms of Fusarium wilt, based on a degree-days threshold of 11.9°C (53.5°F), was used as a basis for determining disease progress curves and the phe...
TL;DR: The Myrobalan plum bears a complete-spectrum resistance to the root-knot nematodes (RKN) Meloidogyne spp.
Abstract: The Myrobalan plum, Prunus cerasifera, bears a complete-spectrum resistance to the root-knot nematodes (RKN) Meloidogyne spp. in comparison to the main resistance sources in Amygdalus rootstocks that have more restricted spectra, as evidenced by a differential resistance test based on the predominant species M. arenaria, M. incognita and M. javanica and the population M. sp. Floride. Resistance to M. arenaria (A) in Myrobalan plum is controlled by the Ma major resistance genes that are completely dominant and confer a non-host behaviour that totally prevents the multiplication of the nematode. The inheritance of resistance of this self-incompatible species to M. incognita (I), M. javanica (J) and the population M. sp. Floride (F), considered as belonging to a new RKN species, was studied using G1 hybrids from a diallel cross based on five parents, the two resistant P.2175 (Ma1 gene; heterozygous) and P.1079 (Ma2 gene; homozygous) and three host parents, P.2032, P.2646 and P.16.5 (recessive for both genes), completed with the G2 backcrosses P.16.5×(P.2646×P.1079), P.2646 ×(P.16.5×P.1079) and P.2175×(P.2646×P.1079). G1 and G2 clones obtained from softwood cuttings sampled from trees in the field experimental design, rooted in the nursery, and inoculated in containers (six replicates per clone) under greenhouse conditions, were simultaneously evaluated for their host suitability to two to four of the RKN species, based on a 0–5 gall index (GI) rating under a high and durable inoculum pressure of the nematode, and then classified into resistant (R; GI?0.2) or host (H; GI?1.3) classes. The resistance classification of each individual clone, evaluated to two (A/J: 319 clones), three (A/J/I: 249 clones) and four (A/J/I/F: 161 clones) RKN species, from segregating and non-segregating crosses involving either Ma1 or Ma2 or both or none, was identical whatever the species. The independence of the R/H classification from the tested RKN indicates that the Ma1 and Ma2 genes control resistance to all of them, and it is assumed that these genes also control resistance to other minor RKN species. The relationship of the Ma genes with the putative genes involved in Amygdalus sources is discussed with the objective of introducing them into new interspecific rootstocks expressing a complete-spectrum and high-level resistance.
01 Jan 1997
TL;DR: A comparison with cyst-forming nematodes highlights two important features during Meloidogyne migration which are discussed: the intercellular movement of the juveniles through plant tissues and the ability of orientation within the root tip.
Abstract: Research on the invasion and migration behaviour of sedentary nematodes is reviewed, with emphasis on the root-knot nematodes, Meloidogyne spp., and with particular reference to the orientation in the host, changes that occur in the nematode, the importance of nematode secretory products and the response of the plant. A comparison with cyst-forming nematodes highlights two important features during Meloidogyne migration which are discussed: the intercellular movement of the juveniles through plant tissues and the ability of orientation within the root tip. As the second-stage juveniles of all Meloidogyne species show this behaviour independent of the host, future research on these two topics may provide information leading to the development of plants with resistance to root-knot nematodes that operates during the early stages of infection.
TL;DR: In this paper, the authors describe 80% of the users' satisfaction with 80%含有する製剤 and 80% satisfaction with the 80% success rate.
Abstract: サニーム (アザディラクチンを80%含有する製剤) またはニーム油の懸濁液にトマト種子を浸漬後, 乾燥した。この種子を播種し, 3週間後に得られた苗をサツマイモネコブセンチュウが接種された土壌に移植した. 2か月後に根瘤の発生状況, 地上部の成長状態, 土壌中の線虫の密度を調べた. サニーム, ニーム油共に, 100倍以下の希釈濃度でサツマイモネコブセンチュウの防除に効果が認められた.
Journal Article•
TL;DR: Ascorbate peroxidase was found to occur commonly in phytoparasitic nematodes, with the highest activity in the invading life-stages, and in all the life stages examined, the antioxidant enzyme activities of M. hapla were markedly higher than those ofM.
Abstract: Presence of different antioxidant enzymes, such as superoxide dismutase (SOD), catalase, and ascorbate, p-phenilendiamin e-pyrocathecol (PPD-PC), o-dianisidine, and guaiacol isoperoxidases, was shown in the phytoparasific nematode species Meloidogyne incognita, M. hapla, Globodera rostochiensis, G. pallida, Heterodera schachtii, H. carotae, and Xiphinema index. The activity of the enzymes tested differed among the life stages examined. SOD was present in cysts but was not detected in Meloidogyne egg masses. Catalase activity of Meloidogyne females was higher than that of preparasitic stages and cyst-nematode females. );or the first time, ascorbate peroxidase was found to occur commonly in phytoparasitic nema- todes, with the highest activity in the invading life-stages. In all the life stages examined, the antioxidant enzyme activities of M. hapla were markedly higher than those of M. incognita. Glutathione peroxidase was not found in the species examined. Phytoparasitic nematodes are aerobic or- ganisms (Atkinson, 1980). Aerobes must deal with the high reactivity of oxygen, which can sequentially acquire four elec- trons, forming toxic intermediates in the process; several of these are free radicals. Moreover, production of active oxygen (AO) species occurs in the plant-pathogen interaction (gauss, 1990; Dixon et al., 1994; Baker and Orlandi, 1995). Therefore, nema- todes must deal not only with AO generated by their own metabolism but also with those produced by the host in response to their attack, thus suggesting the need for antioxi- dant mechanisms in such parasites. A pre- liminary investigation of second-stage juve- niles ()2) of Meloidogyne incognita and M. hapla revealed that they may have an enzy- matic system of superoxide dismutase (SOD) and ascorbate peroxidase, which neutralize superoxide anions (02-) to H20 through H20 2 (Molinari, 1995). AO production in plants is particularly im- portant in the defense mechanism as well as in the recognition of incompatible patho- gens (Baker and Orlandi, 1995). A relatively
Journal Article•
TL;DR: Results indicate that higher chitinase activity and early induction of specific chit inase isozymes may be associated with resistance to root-knot nematode in soybean.
Abstract: Host physiological events in relation to infestation by parasitic nematodes are not well documented. Soybean plant responses to Meloidogyne incognita infestation were compared to resistant (Bryan) and susceptible (Brim) cultivars at 0, 1, 3, 10, 20, and 34 days after infestation (DAI). The resistant cultivar had higher chitinase activity than the susceptible cultivar at every sample time beginning at 3 DAI. Results from isoelectric focusing gel electrophoresis analyses indicated that three acidic chitinase isozymes with isoelectric points (pIs) of 4.8, 4.4, and 4.2 accumulated to a greater extent in the resistant compared to the susceptible cultivar following challenge. SDS-PAGE analysis of root proteins revealed that two proteins with molecular weights of approximately 31 and 46 kD accumulated more rapidly and to a higher level in the resistant than in the susceptible cultivar. Additionally, three major protein bands (33, 22, and 20 kD) with chitinase activity were detected with a modified SDS-PAGE analysis in which glycolchitin was added into the gel matrix. These results indicate that higher chitinase activity and early induction of specific chitinase isozymes may be associated with resistance to root-knot nematode in soybean.
Journal Article•
TL;DR: In an integrated approach to management of nematodes in maize, the effects of compost amendment and culfivar choice acted independently, apparently, cultivar choice is more important than amendment with yard waste compost for management of M. incognita population levels in a maize rotation crop.
Abstract: Effects of yard waste compost and maize (Zea mays) cultivar on population densities of plant-parasitic nematodes were examined in four experiments in north Florida. In one experiment, eight maize cultivars were evaluated; the other three experiments involved split-plot designs with compost treatments as main plots and maize cultivars as subplots. The three compost treatments used in these experiments were: 269 mt/ha of a yard-waste compost applied to the soil surface as a mulch, 269 mt/ha of compost incolporated into the soil, and an unamended control. No interactions between compost treatment and cultivar occurred in any experiment. Effects of compost treatment on Mesocriconema spp., Meloidogyne incognita, and Pratylenchus spp. were inconsistent, whereas significant effects of compost on population densities of Paratrichodorus minor were found on four of six sampling occasions. Cultivar affected final population densities (Pf) of M. incognita. In two tests, Pf of M. incognita on a Florida subtropical experimental hybrid (Howard III) were only 36% and 23% of Pf on the standard tropical hybrid (Pioneer Brand X304C). In an integrated approach to management of nematodes in maize, the effects of compost amendment and culfivar choice acted independently. Apparently, cultivar choice is more important than amendment with yard waste compost for management of M. incognita population levels in a maize rotation crop.
15 Jun 1997
TL;DR: Seed extracts of Acacia eburnean, Azadirachta indica, Cassia sp.
Abstract: Seed extracts of Acacia eburnean, Azadirachta indica, Cassia sp., Parkinsonia aculeate, Sesbania sesban and Poinciana regia had the highest nematicidal potential against Meloidogyne incognita juveniles while maximum potential against M. javanica was shown y A. eburnean, Cassia sp., Melia azedarach, S. sesban and Tribulus terrestris, as indicated by strong activity in all concentrations. Similarly, Calotropis procera and S. sesban were the best in preventing egg batch of M. incognita, and C. procera, S. sesban and Chenopodium album were the most effective against hatch of M. javanica eggs. S. sesban was outstanding in killing juveniles and preventing latching of both the species.
TL;DR: It is hypothesize that, in infected plants, the diffusive intake of gaseous pollutants would be greater and the interaction between the nematode and pollutant(s) would be governed by the degree of stomatal opening, and a positive correlation was observed betweenStomatal pore width and rate of transpiration.
TL;DR: Eight cotton cultivars, with and without aldicarb treatment, were evaluated for their effect on the severity of the root-knot nematode-Fusarium wilt disease complex in cotton.
Abstract: Eight cotton cultivars, with and without aldicarb treatment, were evaluated for their effect on the severity of the root-knot nematode-Fusarium wilt disease complex in cotton. A randomized complete block design with a split-plot arrangement of treatments was used with cotton cultivars as the main plots and nematicide treatments as the subplots. Results in 1994 and 1995 were similar. Yield of lint, boll weight, and wilt and root-gall ratings were different among cultivars and between nematicide treatments both years. Increased lint yield and boll weight, and reduced root-gall and wilt ratings were associated with application of aldicarb. Increased lint percentage was associated with application of aldicarb in 1994, but not in 1995. Fiber micronaire, elongation, uniformity, and strength were different among cultivars, but not between nematicide treatments. Fiber length (UHM; Upper-Half Mean) was different among cultivars and was higher in the aldicarb-treated plots in both years. Numbers of Meloidogyne incognita second stage juveniles and eggs extracted from soil samples were lower in the aldicarb-treated plots in July, but not at harvest, both years. Population densities of M. incognita were not different among cultivars, except the mid-season sample in 1995.
TL;DR: The resistant Scotch Bonnet cultigens may serve as sources of resistance for development of root-knot nematode-resistant Habanero peppers.
Abstract: Scotch Bonnet and Habanero peppers, extremely pungent cultivar classes of Capsicum chinense Jacq., are increasing in popularity in the United States. Because the southern root-knot nematode, Meloidogyne incognita (Kofoid & White) Chitwood, is a major pest of many C. annuum cultivars, a series of greenhouse and field experiments was conducted to determine if Scotch Bonnet and Habanero peppers from available commercial and private sources also are vulnerable to the pest. In an initial greenhouse test, a collection of 59 C. chinense cultigens was evaluated for reaction to M. incognita race 3. All cultigens obtained from commercial sources were moderately susceptible or susceptible. However, four accessions obtained through Seed Savers Exchange listings exhibited high levels of resistance. Three of these cultigens (PA-353, PA-398, and PA-426) were studied in subsequent greenhouse and field plantings, and each was confirmed to have a level of resistance similar to that available in C. annuum. All three of the resistant cultigens are well-adapted and each is potentially useful in commercial production without further development. None of the Habanero cultigens was resistant to the southern root-knot nematode. The resistant Scotch Bonnet cultigens may serve as sources of resistance for development of root-knot nematode-resistant Habanero peppers.
01 Jan 1997
TL;DR: The 14 kDa protein may represent the product of a novel, root knot nematode-inducible plant gene whose expression is temporally correlated with the resistance response to root Knot Nematode.
Abstract: The cotton (Gossypium hirsutum L.) germplasm, Auburn 634 and others derived from this source, contain resistance genes that effectively inhibit reproduction of root knot nematode (Meloidogyne incognita [Kofoid and White] Chitwood, race 3). Although infective root knot nematode juveniles penetrate the resistant cotton lines in numbers similar to susceptible lines, nematode development is arrested in the resistant lines soon after infection. Analyses of root proteins via one- and twodimensional polyacrylamide gel electrophoresis (PAGE) revealed a relatively abundant 14 kilodalton (kDa) polypeptide that was differentially expressed in resistant isoline 81-249 at 8 d after inoculation. Dissection of nematodes from equivalent root samples and their analysis separate from the root tissue showed that the 14 kDa was a plant protein. Expression of the 14 kDa protein in infected roots of 81-249 was localized to the nematodeinduced galls. Digestion of the polypeptide with cyanogen bromide (CNBr) yielded two major fragments of 9 and 4 kDa from which partial amino acid sequences were obtained. Comparison of these partial sequences with gene databases did not reveal strong homologies with other sequences. Thus, the 14 kDa protein may represent the product of a novel, root knot nematode-inducible plant gene whose expression is temporally correlated with the resistance response to root knot nematode.
15 Dec 1997
TL;DR: Seven olive cultivars and one rootstock were tested in a glasshouse experiment for their reaction to Meloidogyne incognita and M. javanica, finding that Cellina di Nardo was susceptible to both nematodes, as cultivars Frantoio and FS 17 and the rootstock DA 12 I were moderately susceptible.
Abstract: Seven olive cultivars and one rootstock were tested in a glasshouse experiment for their reaction to Meloidogyne incognita and M. javanica. Potted soil was artificially infested with 12 eggs and juveniles/cm³ of either nematode species. Cultivar Coratina was resistant to M. incognita and M. javanica and cv. Leccino was resistant to M. javanica and moderately susceptible to M. incognita. Cultivar Cima di Bitonto was moderately susceptible to M incognita and highly susceptible to M. javanica and cv. Cellina di Nardo was susceptible to both nematodes, as cultivars Frantoio and FS 17 and the rootstock DA 12 I were moderately susceptible. Cultivar Yusti, which had the least developed root system of all those tested, was moderately susceptible to M. incognita and moderately resistant to M. javanica.
Journal Article•
TL;DR: Genotypes of wild Solanum species were tested to determine the level of resistance to root-knot nematodes and to detect the presence of virulent populations within Meloidogyne chitwoodi, M. fallax and M. hapla.
Abstract: Genotypes of wild Solanum species were tested to determine the level of resistance to root-knot nematodes and to detect the presence of virulent populations within Meloidogyne chitwoodi, M. fallax and M. hapla. High resistance to all tested populations of M. chitwoodi and M. fallax was observed in genotypes of Solanum bulbocastanum, S. hougasii, S. cardiophyllum and S. fendleri. Some genotypes of S. chacoense and S. stoloniferum showed moderate resistance to M. fallax, but no or lesser resistance to M. chitwoodi. There was little variation in virulence in populations of M. chitwoodi and M. fallax found on resistant plants. In contrast, large differences in virulence toward resistant genotypes of S. bulbocastanum, S. hougasii, S. chacoense, S. gourlayi, S. sparsipilum and S. spegazzinii were observed between four populations of M. hapla. It was found that resistance to M. chitwoodi, M. fallax and/or M. hapla is not linked to resistance to the nematode species adapted to high temperature, i.e., M. incognita, M. arenaria and M. javanica.
15 Jun 1997
TL;DR: Application of poultry and cattle manures, inorganic fertilizer in the form of urea and neem-based urea-coating agent 'Nimin' and biopesticide 'Suneem G' significantly reduced populations of Meloidogyne incognita and other plant-parasitic nematode and their symptoms on the plant and increased the populations of microbivorous nematodes.
Abstract: Application of poultry and cattle manures, inorganic fertilizer in the form of urea and neem-based urea-coating agent 'Nimin' and biopesticide 'Suneem G' significantly reduced populations of Meloidogyne incognita and other plant-parasitic nematodes and their symptoms on the plant and increased the populations of microbivorous nematodes. Enhanced growth of tomato in treated soil was directly correlated with the suppression of plant-parasitic nematode populations. Higher dosages resulted in greater effects.
01 Jan 1997