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1.
Pratylenchus thornei -chickpea interactions were investigated under controlled and fluctuating environmental conditions in the growth chamber, greenhouse and shadehouse. Under controlled conditions, P. thornei infected chickpea lines 12071/10054 and P2245 and cultivars Andoum 1, JG62 and UC27. Line P 2245 and cv. JG 62 were the most susceptible genotypes on the basis of root damage and nematode reproduction, but nematode infection did not significantly reduce root and shoot weights. Cultivars Andoum 1 and UC27 and line 12071/10054 showed the least root damage and nematode reproduction. Inoculation of cv. Andoum 1 with 2500, 5000 or 10000 nematodes per plant in pots did not affect shoot weight, regardless of the conditions of water stress of the plants. However, root weight was significantly reduced by nematode infection in plants grown under water stress and fluctuating temperature conditions in the greenhouse, but was not affected by any other treatment. The nematode reproduction index was not affected by soil water content under shadehouse conditions, but was greater on plants watered to soil water-holding capacity than in water-stressed plants under greenhouse conditions. For both environments, the nematode reproduction index decreased when inoculum density was greater than 5000 nematodes per plant. 相似文献
2.
ABSTRACT Fusarium oxysporum f. sp. ciceris and the root-lesion nematode Pratylenchus thornei coinfect chickpeas in southern Spain. The influence of root infection by P. thornei on the reaction of Fusarium wilt-susceptible (CPS 1 and PV 61) and wilt-resistant (UC 27) chickpea cultivars to F. oxysporum f. sp. ciceris race 5 was investigated under controlled and field conditions. Severity of Fusarium wilt was not modified by coinfection of chickpeas by P. thornei and F. oxysporum f. sp. ciceris, in simultaneous or sequential inoculations with the pathogens. Root infection with five nematodes per cm(3) of soil and 5,000 chlamydospores per g of soil of the fungus resulted in significantly higher numbers of propagules of F. oxysporum f. sp. ciceris with the wilt-susceptible cultivar CPS 1, but not with the wilt-resistant one. However, infection with 10 nematodes per cm(3) of soil significantly increased root infection by F. oxysporum f. sp. ciceris in both cultivars, irrespective of fungal inoculum densities (250 to 2,000 chlamydospores per g of soil). Plant growth was significantly reduced by P. thornei infection on wilt-susceptible and wilt-resistant chickpeas in controlled and field conditions, except when shorter periods of incubation (45 days after inoculation) were used under controlled conditions. Severity of root necrosis was greater in wilt-susceptible and wilt-resistant cultivars when nematodes were present in the root, irrespective of length of incubation time (45 to 90 days), densities of nematodes (5 and 10 nematodes per cm(3) of soil), fungal inocula, and experimental conditions. Nematode reproduction on the wilt-susceptible cultivars, but not on the wilt-resistant one, was significantly increased by F. oxysporum f. sp. ciceris infections under controlled and field conditions. 相似文献
3.
Several endoparasitic nematodes have been reported on leguminous plants in the Mediterranean area. The most widespread are the root-lesion nematodes Pratylenchus mediterraneus, P. penetrans and P. thornei. Symptoms induced by these nematodes usually are not very impressive, but 50% yield loss of chickpea may occur. Among root-knot nematodes, Meloidogyne artiellia is associated with severe yield losses of chickpea in Italy, Spain and especially Syria. Tolerance limits of 0.14 and 0.02 of this nematode per ml soil are reported for winter and spring-sown chickpea, respectively. Meloidogyne incognita and M. javanica can be noxious to French bean and cowpea in sandy soil. The cyst nematode Heterodera goettingiana reduces yields of pea, broad bean and vetch when its population densities exceed 0.5, 1, and 2.1 eggs per g of soil, respectively. Heterodera ciceri occurs in northern Syria and Turkey and is responsible for economic yield losses of chickpea and lentil in fields infested with more than 1 or 2.5 eggs per g of soil, respectively. Pea and grass pea also suffer from infestation of this nematode. The stem and bulb nematode Ditylenchus dipsaci causes severe decline of broad bean, pea and probably lentil during wet seasons. Other nematodes, although present in moderate numbers, appear to have little importance. 相似文献
4.
Four populations of Pratylenchus thornei from different locations were tested for reproductive fitness in axenic carrot disc cultures and for pathogenicity to chickpea cultivars JG 62 and UC 27 and lines K 850 and ILC 1929. Parasitism and histopathology on selected chickpea genotypes (JG 62, UC 27 and lines ILC 482, ICC 11324 and ICC 12237) were also investigated. Reproductive fitness, assessed as the ratio of the final number of nematodes per carrot disc to the number of nematodes inoculated, was similar among the populations tested and the four populations reproduced to a similar extent in a given chickpea genotype. However, the extent of reproduction was significantly affected by the chickpea genotype, JG 62 and UC 27 being the best and poorest hosts, respectively. Pathogenicity to chickpea genotypes was assessed by the difference in fresh root and dry shoot weights between infected and uninfected plants 90 days after inoculation. Plant growth was significantly reduced by the four nematode populations in all chickpea genotypes, with the exception of cv. JG 62, which was tolerant of P. thornei . Severity of root necrosis caused by nematode infection was similar for all populations. Histopathological studies of chickpea genotypes infected by P. thornei showed that all were suitable hosts according to nematode reproduction and host reaction. P. thornei always migrated through epidermal and cortical cells by breaking down cell walls along the nematode pathway. In the most susceptible lines (ILC 482 and JG 62), damage to endodermal cells adjacent to nematode feeding sites was occasionally observed. 相似文献
5.
Pratylenchus thornei invaded excised pea roots in agar in greater numbers and penetrated the cortex more deeply than P. crenatus . Both species fed on the roots ectoparasitically and displaced root cells into the surrounding medium. The cytoplasm of cortical cells near cither nematode became granulated, with enlarged vacuoles and nuclei. P. thornei also caused these responses in the endodermis. Infection of the root surface with a grey sterile fungus inhibited invasion by P. crenatus and P. thornei . Infection by Thielaviopsis basicola inhibited P. thornei invasion but encouraged penetration by P. crenatus and the hyphae were found deeper in the cortex when P. crenatus was present. 相似文献
6.
A rapid method for direct detection of Polymyxa DNA in soil 总被引：1，自引：0，他引：1
Polymyxa spp. are vectors for a number of economically important soilborne plant viruses. The development of a technique to detect virus and vectors directly in soil would be useful for epidemiological studies and assessment of disease risk prior to planting. A rapid method was developed to extract and quantify Polymyxa spp. DNA from soils. DNA was extracted from three soils infested with Polymyxa betae and three infested with P. graminis using an EDTA lysis buffer in combination with a MagneSil™ DNA extraction kit and Kingfisher™ magnetic particle processor. Primers and probes designed to correspond to sequences within the internal transcribed spacer region 2 (ITS2) of ribosomal DNA enabled recovery and amplification of P. betae and P. graminis DNA using real-time PCR and TaqMan chemistry. For the P. graminis- infested soils, the purity of DNA obtained was sufficient to allow Polymyxa DNA to be amplified without dilution to remove inhibitors, but with P. betae- infested soils, amplification was only achieved if the DNA was diluted 1:10. Using TaqMan PCR, a standard curve was constructed from uninfested soil spiked with known numbers of P. betae cystosori; the quantity of P. betae inoculum from naturally infested soil was then extrapolated from the curve. This technique offers a sensitive method of extracting, detecting and quantifying Polymyxa spp. DNA in soil. 相似文献
7.
Influence of aldicarb on root lesion nematodes, leaf disease and root rot in wheat and barley 总被引：1，自引：0，他引：1
The effects of aldicarb on populations of root lesion nematodes (primarily Pratylenchus penetrans ) and on grain yields of spring barley and wheat were examined in the field over 3 years, 1981*83. The incidence of barley net blotch ( Pyrenophora teres ), wheat leaf blotch ( Leptosphaeria nodorum ), and common root rot ( Cochliobolus sativus ) was also recorded in 1982 and 1983. Aldicarb treatments reduced the size of root lesion nematode populations in soil and roots in all years, except in the mid-season soil sample in 1983. The severity of leaf disease was decreased only in 1982, but the incidence of root rot was not significantly affected by the nematticide. Although aldicarb increased cereal grain yields by approximately 15% there was no significant relationship between numbers of root lesion nematodes in roots and soil and fungal disease symptoms on barley and wheat. 相似文献
8.
A 2-year study investigated the relationship between the nematicides aldicarb and fosthiazate and populations of plant growth-promoting (PGP) and plant-growth-inhibiting (PGI) bacteria, and root-lesion nematodes and bacteria-feeding nematodes in the root-zone soils of potatoes. Fewer ( P < 0.05) bacterial genera and species were recovered from aldicarb-treated soils than from the fosthiazate and untreated soils but bacterial population densities were greatest in the aldicarb-treated soils. In potato plantlet bioassays using root-zone bacteria from the three soil sources, bacteria from the aldicarb-treated soils reduced ( P < 0.01) the mean wet and dry weight of shoots and roots compared with those from the fosthiazate and untreated soils. In the field, fosthiazate (but not aldicarb) significantly increased tuber yields and reduced nematode population densities of Pratylenchus penetrans in roots and soil. Population densities of bacteria-feeding nematodes (primarily Diplogaster lheritieri ) were not affected by either nematicide. Aldicarb appeared to suppress the populations of plant-growth-promoting bacteria that contribute to enhanced growth in potatoes. This is attributed to the long-term use of aldicarb at the trial site, which may have encouraged the selection, or adaptation, of soil microorganisms that degrade carbamate pesticides but do not enhance potato growth. 相似文献
9.
为明确河南省小麦根腐线虫病的发生危害情况及其病原线虫种类,对14个县(市)45个采样点小麦根腐线虫进行了分离调查,分别通过人工接种测定其致病性和杀线剂处理研究其危害性,并采用形态学和分子生物学方法鉴定其病原。结果显示:小麦根腐线虫在河南省的分布具有一定的区域性,中北部的10个县(市)34个沙质土壤采样点均分离出小麦根腐线虫,而在南部土壤粘重地区的小麦根内和土壤中均没有分离出根腐线虫;15%涕灭威颗粒剂处理土壤后小麦的穗粒数、千粒重和单位面积产量较对照明显上升,产量增加13.6%;该线虫能够侵染小麦,并明显抑制小麦生长;河南省小麦根腐线虫以敏捷短体线虫Pratylenchus agilis为主。 相似文献
10.
11.
Fouad Mokrini Lieven Waeyenberge Nicole Viaene Fouad Abbad Andaloussi Maurice Moens 《European journal of plant pathology / European Foundation for Plant Pathology》2013,137(2):403-413
Pratylenchus penetrans is one of the most economically damaging plant-parasitic nematodes and is found on a wide variety of crops. Correct identification and quantification of this nematode are necessary for providing advice to farmers, but are not easily obtained with the traditional way of microscopic observation. We developed a qPCR assay to detect and quantify P. penetrans in a short but accurate manner. A qPCR primer set, including two primers and a TaqMan probe, was designed based on the sequence of the β-1,4-endoglucanase gene. The assay was optimized by using the primers in a qPCR assay with SYBR green I dye and setting the qPCR program to different annealing temperatures ranging from 60 °C to 64 °C. Based on the Ct-values, we retained the program with an annealing temperature of 63 °C. The assay with the probe was very sensitive as it was able to detect a single individual of P. penetrans, even when mixed with up to 80 individuals of P. thornei. The specificity of the reaction was confirmed by the lack of amplification of DNA from 28 populations of 18 other Pratylenchus species and from plant-parasitic nematodes from nine other genera. DNA from 21 different isolates from P. penetrans was amplified. DNA extraction from 80 individuals and quantification by qPCR was repeated four times; Ct-values showed consistent results (Ct?=?24.4?±?0.4). A dilution series from DNA of P. penetrans resulted in a standard curve showing a highly significant linearity between the Ct-values and the dilution rates (R2?=?0.99; slope?=??3.23; E?=?104 %). The tests showed a high correlation between the real numbers of nematodes and the numbers detected by the qPCR. The developed qPCR assay provides a sensitive means for the rapid detection and reliable quantification of individuals of this pest. This method does not require expertise in nematode taxonomy and morphology, and can be used as a rapid diagnostic tool in research, as well as in diagnostic labs and extension services advising farmers for pest management. 相似文献
12.
Detection and analysis of inter- and intraspecific diversity of Pratylenchus spp. using isozyme markers 总被引：1，自引：0，他引：1
The root-lesion nematodes of the genus Pratylenchus are an economically important group of plant parasitic nematodes that show high similarity among sibling species. Isozyme patterns obtained by isoelectrofocusing (IEF) were used to differentiate and establish genetic relatedness among Pratylenchus species. A total of 40 populations comprising 9 Pratylenchus species and Radopholus similis from broad host and geographic origins was examined to compare isozyme patterns of esterase (EST), hexoquinase (HK), isocitrate dehydrogenase (IDH), malate dehydrogenase (MDH), phosphoglucose isomerase (PGI), phosphoglucomutase (PGM) and superoxide dismutase (SOD). Of these systems, only EST, MDH, PGI and PGM were useful for differentiation of P. vulnus , P. goodeyi , P. penetrans , P. scribneri , P. thornei and R. similis populations. The greatest intraspecific diversity was found within P. coffeae based on the isozyme patterns for MDH, PGI and PGM. Intraspecific variability was also detected among R. similis populations, which showed two isozyme patterns in EST and PGI systems. Less intraspecific variation was found within the P. penetrans group. The P. goodeyi population from Cameroon differed from the other populations in this specific group in its MDH, PGI and PGM phenotypes. Highly similar banding patterns of EST, MDH and PGI activity were found among the P. scribneri populations and the one population of P. agilis . A cluster analysis of the 40 populations, generated from the four enzyme banding patterns, produced groupings that broadly matched the previous classification into specific groups, reflecting intraspecific variability in some cases. The results confirm the potential use of isozyme patterns as markers for these nematode species and their value for diagnostic application. 相似文献
13.
ABSTRACT Studies were conducted to assess the impact of short-term rotations of wheat on microbial community composition and growth of apple in soils from replant orchard sites. Soils from two orchards were cultivated with three successive 28-day growth cycles of 'Eltan', 'Penewawa', or 'Rely' wheat in the greenhouse and subsequently planted to 'Gala' apple seedlings. Cultivation of orchard replant soils with any of the three wheat cultivars enhanced growth of apple relative to that achieved in untreated soils. Improved growth was associated with a marked reduction in apple root infection by species of Rhizoctonia and Pythium. Populations of plant-parasitic nematodes were below damage threshold levels in these orchard soils; however, apple seedlings grown in wheat-cultivated soils had significantly lower root populations of Pratylenchus spp. than did seedlings grown in untreated soils. Growth of apple in 'Penewawa'-cultivated soils often was superior to that observed in soils planted with 'Eltan' or 'Rely'. In untreated orchard soils, fluorescent pseudomonad populations isolated from soil and the apple rhizosphere were dominated by Pseudomonas fluorescens biotype C and Pseudomonas syringae. Cultivation of replant soils with wheat induced a characteristic transformation of the fluorescent pseudomonad population, and Pseudomonas putida dominated the population of this bacterial group recovered from wheat-cultivated replant orchard soils. Results from this study suggest that use of short-term wheat cropping sequences during orchard renovation could be useful in management of replant disease and that this disease-control option may operate, in part, through modification of the fluorescent pseudomonad community. 相似文献
14.
Many field experiments in England and Wales during the past 20 years have measured cereal yield losses and established regressions of yield on numbers of Heterodera avenae. Yield benefits from soil sterilants were greatest where most H avenae was present. Isogenic selections of barley and oats resistant and susceptible to H. avenae were extensively grown to assess the losses caused by this nematode alone. In some experiments these losses were identical with those measured by nematicide use, but in others (notably where broad spectrum biocides were used) losses were greater than those attributable to H. avenae and could be explained only by the known incidence of accompanying pathogens. Some yield loss may be due to migratory nematodes, e.g. Pratylenchus spp. occurring with H. avenae. Barley and wheat yields in the last 30 years have increased by 63 and 84 % due to improvements in cultivars and farming practice. Smaller percentage loss in a high yielding crop can be as costly as large percentage loss in poor crops grown on dry light soils. Many factors - soil type, rainfall, nutrients, other pathogens etc. - can greatly modify crop responses to similar popuiation levels of H. avenae. 相似文献
15.
A 3-year field study examined the effects of 1,3-dichloropropene or oxamyl on tuber yields in four early- and five late-maturing potato cultivars. The nematicide treatments increased total tuber yield by ≈ 12% for early-maturing cultivars, but by less than 2% for the late-maturing cultivars. The treatments reduced the numbers of root lesion nematodes (primarily Pratylenchus penetrans ), which were the dominant plant parasitic nematodes at the site. Covariance analysis indicated that treatment effects on total tuber yield were no longer significant after adjusting for root lesion nematodes in soil at harvest, confirming that these nematodes had a direct effect on the host. As expected, there were significant inverse relationships ( P = 0·05) between total tuber yields and numbers of root lesion nematodes in soil and in roots. However, the application of nematicides in late-maturing cultivars was found to be of no practical value. Crop production systems designed to reduce or optimize pesticide applications can form one criterion in the development of more environmentally sensitive management strategies. The merit of utilizing chemicals for root lesion nematode control are considered with regard to cultivar maturity. 相似文献
16.
Francesca De luca Elena Fanelli Mauro Di vito Aurelio Reyes Carla De giorgi 《European journal of plant pathology / European Foundation for Plant Pathology》2004,110(9):949-957
Plant parasitic nematodes belonging to the genus Pratylenchus, also known as root lesion nematodes, cause serious economic damage to different crop plants. In order to explore genetic structures in different isolates, we investigated several P. thornei,
P. neglectus and P. penetrans populations of different geographic origins. The analysis at the species level was also extended to P. penetrans, P. pinguicaudatus, P. vulnus and P. mediterraneus. Sequence analysis of a specific portion of DNA was carried out. In particular, the sequences of the D3 region of the 26S gene were obtained and compared with similar sequences available in databases. The results support the hypothesis that P. penetrans may represent a species complex, while in P. neglectus the intra-species heterogeneity observed is due to intra-individual variability. Furthermore, the specific conservation of some nucleotides in different P. thornei populations indicates their fixation in the rDNA repeats in this species. The presence of these nucleotides, the molecular signature of P. thornei, may assist in determining the nature of nematode infections. 相似文献
17.
Development of a real‐time PCR method for the detection of the dagger nematodes Xiphinema index,X. diversicaudatum,X. vuittenezi and X. italiae,and for the quantification of X. index numbers 
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下载免费PDF全文 The ectoparasitic dagger nematodes Xiphinema index and Xiphinema diversicaudatum, often at low numbers in the soil, are vectors of grapevine nepoviruses, which cause huge agronomical problems for the vineyard industry. This study reports a method, based on real‐time PCR, for the specific detection of these species and of the closely related non‐vector species Xiphinema vuittenezi and Xiphinema italiae. Specific primers and TaqMan probes were designed from the ribosomal DNA internal transcribed spacer 1 (ITS1), enabling the specific detection of single individuals of each of the X. index, X. diversicaudatum, X. italiae and X. vuittenezi species whatever the nematode population. The specificity of detection and absence of false positive reaction were confirmed in samples of each species mixed with the three other Xiphinema species or mixed with nematodes representative from other genera (non‐plant‐parasitic Dorylaimida, Longidorus sp., Meloidogyne spp., Globodera spp. and Pratylenchus sp.). The method was shown to be valid for the relative quantification of X. index numbers through its use, from crude nematode extracts of soil samples, in a greenhouse assay of grapevine accessions ranging from highly susceptible to resistant. As an alternative to time‐consuming microscopic identification and counting, this real‐time PCR method will provide a fast, sensitive and reliable diagnostic and relative quantification technique for X. index nematodes extracted from fields or controlled conditions. 相似文献
18.
The impact of resistant and susceptible wheat cultivars on the multiplication of Heterodera filipjevi and H. avenae in parasite‐infested soil 下载免费PDF全文
下载免费PDF全文 L. Cui L. Sun X. Gao W. Song X. M. Wang H. L. Li Z. Y. Liu W. H. Tang H. J. Li 《Plant pathology》2016,65(7):1192-1199
Cereal cyst nematode (CCN) severely threatens wheat production in many regions of China. Cultivars susceptible to CCN are the main reason for its spread. This study was initiated to determine whether wheat cultivars conferring different resistance levels are the dominant determinants of CCN populations in the rhizospheric soil. Field experiments were conducted at two locations in Henan province, China, where high populations of Heterodera filipjevi or H. avenae have occurred, during the growing seasons of 2010/11 and 2011/12. Conventional enumeration of white female nematodes on the plant roots, reproductive factor (Rf) and a molecular diagnostic approach, PreDicta B test, a soil testing service based on a sensitive quantitative PCR technique, were used to determine the nematode populations in the rhizospheric soils of seven common wheat and durum wheat cultivars with different reactions to CCN. The resistant responses to CCN conferred by durum wheat Wascana and Wakooma and common wheat Madsen were effective against both H. filipjevi and H. avenae and resulted in significantly fewer nematodes (<5 females) on the roots, and lower Rf. Those cultivars were effective in limiting nematode propagation, resulting in fewer CCN eggs in their rhizospheric soils. Taikong 6 conferred moderate resistance (5–10 females) to both Heterodera species. Tianmin 668 only showed resistance to H. avenae. Aikang 58 and Wenmai 19 were susceptible to both CCN species, which facilitated increases in the nematode populations. These results demonstrate that the reactions to CCN of wheat genotypes have obvious impact on the propagation of nematodes. 相似文献
19.
Pratylenchus thornei densities were monitored in field plots of two winter wheat cultivars in a dry farming area of southern Spain. Samples were
taken fortnightly during the wheat-growing season and from the following dry fallow. Under bread wheat cv. ‘Yecora’, densities
ofP. thornei increased for 5 to 6 months and then were maintained or slightly decreased thereafter, surviving the summer dry fallow in
an anhydrobiotic state (78.2% and 85.3% survival in soil and roots, respectively). Under durum wheat cv. ‘Donpedro’, nematode
densities decreased over the growing season, although densities within the roots increased during the first 2 months of the
wheat-growing period, indicating that nematodes could penetrate the roots of this cultivar but were unable to reproduce. These
observations suggest resistance of wheat cv. Donpedro toP. thornei. 相似文献
20.
Joseph Esnard Nahum Marban-Mendoza Bert M. Zuckerman 《European journal of plant pathology / European Foundation for Plant Pathology》1998,104(5):457-463
The effect of 24 treatment combinations of cultures of Streptomyces costaricanus sp. nov. (ATCC55274), Bacillus thuringiensis (ATCC55273) and a strain of Paecilomyces marquandii, nematicide (cadusaphos), and/or wheat mash on growth and response of potted banana plants (Musa AAA) and populations of Radopholus similis, Helicotylenchus multicinctus and free living nematodes were studied in Río Frío, Costa Rica. The best plant responses (height, leaf numbers, healthy root weight), lowest numbers of plant parasitic nematodes and highest numbers of free living nematodes were observed for treatments containing wheat as a component. Two treatments, viz. wheat + Streptomyces costaricanus (200-ml culture) and wheat + P. marquandii (200-ml culture), gave the overall best results. Numbers of free living nematodes increased up to 1500-fold only for treatments containing wheat. Significant positive correlations existed between numbers of free living nematodes and shoot weight, healthy root biomass, plant height, and leaf numbers. Non-wheat treatments, including nematicide only, gave the poorest responses in general. Observations of nematodes sampled 50 days following planting in wheat-containing treatments showed most of the free-living nematodes ( 90%) to be infected by nematophagous fungi (species not recorded). The results show that an organic amendment to soil, with or without a microbial component, can be an effective inducer of processes that regulate plant-parasitic nematode populations in soil. 相似文献