A novel chorismate mutase effector secreted from root-knot nematode Meloidogyne enterolobii manipulates plant immunity to promote parasitism

Meloidogyne spp.is an economically important plant-parasitic nematode distributed worldwide.To fight with host immune system for successful parasitism,plant parasitic nematodes secrete effectors to promote infection.In this study,we identified one chorismate mutase(CM)effector from M.enterolobii,named Me-CM.Spatial and temporal expression assays exhibited Me-cm is expressed in esophageal glands and up-regulated at parasitic-stage juveniles.Me-CM affects the pathogenicity of M.enterolobii based on the reduced infection rate,number of galls,egg masses,eggs per mass and multiplication rate collected from RNA silencing experiments.We showed that Me-CM localized in the cytoplasm and nucleus of plant cells and decreased the expression level of the marker gene PR1 of salicylic acid(SA)pathway.Besides,constitutive expression of Me-cm in Arabidopsis thaliana significantly reduced salicylic acid concentration.These results suggested that M.enterolobii may secrete effector Me-CM to fight with plantimmunesystemsvia regulating SA signaling pathway when interacting with host plants,ultimately facilitating parasitism.

Effect of Six Bacterial Strains on the Activity of Second Instar Larvae and Egg Hatching of Meloidogyne incognita

[Objectives]The paper was to screen effective biocontrol strains against Meloidogyne incognita.[Methods]The effect of six bacterial strains sourced from the research group s strain library on the activity of second instar larvae of M.incognita,as well as on egg hatching,was evaluated.[Results]The treatment of fermentation supernatant derived from the X-2 strain exhibited a pronounced lethal effect on M.incognita,with a corrected mortality rate reaching 97%within 72 h.Additionally,this treatment significantly inhibited egg hatching,achieving an inhibition rate of 94.69%at a 20-fold dilution.The strain was identified as Bacillus velezensis,belonging to the genus Bacillus,and was designated as RKN1111.[Conclusions]This study presents alternative strains and a theoretical framework for the biological control of M.incognita.

Resistance analysis of the rice variety Huaidao 5 against root-knot nematode Meloidogyne graminicola

Meloidogyne graminicola has emerged as one of the most destructive plant-parasitic nematodes affecting rice(Oryza sativa)production worldwide.Resistance to M.graminicola in rice could be the most effective option for its management.However,sources of germplasm with resistance to M.graminicola in rice remain limited.Here,we describe the root attraction,gall formation and genetic analysis of the resistance to M.graminicola in the rice variety Huidao 5.A nematode attraction assay showed that second-stage juveniles(J2s)of M.graminicola were attracted at the root tip of Huaidao 5 within 8 h without a significant reduction in attraction compared to the susceptible rice variety Nanjing 9108.Microscopic observation of the infection revealed that the J2s invaded root tissues 12 h after inoculation,but their subsequent movement to the root tip was hindered in Huaidao 5,resulting in decreased nematode number compared to Nanjing 9108.Additionally,we used the soil and hydroponic culture systems to simulate upland and flooding conditions in the paddy fields respectively,and found that gall number was significantly reduced,and nematode development was clearly suppressed in Huaidao 5.To investigate the genetic basis of this resistance,cross breeding was performed between the Huaidao 5 and Nanjing 9108 varieties.There was no reduction in the resistance of the F_(1) offspring to M.graminicola in the greenhouse or field trials,suggesting that a dominant gene could control resistance in Huaidao 5.In summary,this study provides a detailed characterization of a novel source of resistance to M.graminicola in rice,which is of great potential for use in crop breeding.

Potential global distribution of the guava root-knot nematode Meloidogyne enterolobii under different climate change scenarios using MaxEnt ecological niche modeling

In recent years,Meloidogyne enterolobii has emerged as a major parasitic nematode infesting many plants in tropical or subtropical areas.However,the regions of potential distribution and the main contributing environmental variables for this nematode are unclear.Under the current climate scenario,we predicted the potential geographic distributions of M.enterolobii worldwide and in China using a Maximum Entropy(MaxEnt)model with the occurrence data of this species.Furthermore,the potential distributions of M.enterolobii were projected under three future climate scenarios(BCC-CSM2-MR,CanESM5 and CNRM-CM6-1)for the periods 2050s and 2090s.Changes in the potential distribution were also predicted under different climate conditions.The results showed that highly suitable regions for M.enterolobii were concentrated in Africa,South America,Asia,and North America between latitudes 30°S to 30°N.Bio16(precipitation of the wettest quarter),bio10(mean temperature of the warmest quarter),and bio11(mean temperature of the coldest quarter)were the variables contributing most in predicting potential distributions of M.enterolobii.In addition,the potential suitable areas for M.enterolobii will shift toward higher latitudes under future climate scenarios.This study provides a theoretical basis for controlling and managing this nematode.

mgr-mir-9 implicates Meloidogyne graminicola infection in rice by targeting the effector MgPDI

MicroRNAs (miRNAs),a class of small non-coding RNAs,are crucial endogenous gene regulators in a range of animals,including plant-parasitic nematodes.Meloidogyne graminicola is an obligate sedentary endoparasite of rice and causes significant yield losses.A number of studies focused on the roles of M.graminicola effectors during the parasitic process;however,how nematode miRNAs regulate its effectors needs elucidating.In this research,we analyzed a cluster of M.graminicola miRNAs obtained at the second-stage juveniles (J2s) stage that are closely linked to the regulation of M.graminicola effectors.There are 49 767 105 total clean reads obtained from three libraries.A total of 233 known miRNAs and 21 novel miRNAs were identified.Among the known miRNAs,mgr-lin-4,mgr-mir-1,mgr-mir-100,mgrmir-86,mgr-mir-279,mgr-mir-87,mgr-mir-71,mgr-mir-9,mgr-mir-50,mgr-mir-72,and mgr-mir-34 are the most abundant11 miRNAs families.Moreover,the expression levels of selected miRNAs were validated by real-time quantitative PCR.We hypothesized that these miRNAs might regulate the expression of secreted effectors during the J2s stage to facilitate its infection.Consistent with this,we found that mgr-mir-9 targets MgPDI,an important M.graminicola effector mRNA.In addition to that,J2s treated with mgr-mir-9 mimics showed down-regulation of MgPDI expression and reduced reproductive ability,alluding mgr-mir-9 is involved in nematode infection.These results provide novel insight into the regulatory functions of M.graminicola miRNAs during the infection and identify miRNAs and their effector targets as potential key management targets to limit parasite survival during the early stages of infection.

A Meloidogyne incognita effector Minc03329 suppresses plant immunity and promotes parasitism

Meloidogyne incognita is a devastating plant-parasitic nematode.Effectors play important roles during the stages of nematodes infection and parasitism,but their molecular functions remain largely unknown.In this study,we characterized a new effector,Minc03329,which contains signal peptide for secretion and a C-type lectin domain.The yeast signal sequence trap experiments indicated that the signal peptide of Minc03329 is functional.In situ hybridization showed that Minc03329 was specifically expressed in the subventral esophageal gland.Real-time qPCR confirmed that the expression level of Minc03329 transcript was significantly increased in pre-parasitic and parasitic second-stage juveniles(pre-J2s and par-J2s).Tobacco rattle virus(TRV)-mediated gene silencing of Minc03329 in host plants largely reduced the pathogenicity of nematodes.On the contrary,ectopic expression of Minc03329 in Arabidopsis thaliana significantly increased plant susceptibility to nematodes.Transient expression of Minc03329 in Nicotiana benthamiana leaves suppressed the programmed cell death triggered by the pro-apoptotic protein BAX.Moreover,the transcriptome analysis of Minc03329-transgenic Arabidopsis and wild type revealed that many defense-related genes were significantly down-regulated.Interestingly,some different expressed genes were involved in the formation of nematode feeding sites.These results revealed that Minc03329 is an important effector for M.incognita,suppressing host defense response and promoting pathogenicity.

Comparative transcriptome analysis provides insights into the molecular mechanism of the anti-nematode role of Arachis hypogaea(Fabales:Fabaceae)against Meloidogyne incognita(Tylenchida:Heteroderidae)

Background:Plant root-knot nematode(RKN)disease is a serious threat to agricultural production across the world.Meloidogyne incognita is the most prominent pathogen to the vegetables and cash crops cultivated.Arachis hypogaea can effectively inhibit M.incognita,but the underlying defense mechanism is still unclear.Methods:In our study,the chemotaxis and infestation of the second-stage juveniles(J2s)of M.incognita to A.hypogaea root tips were observed by the Pluronic F-127 system and stained with sodium hypochlorite acid fuchsin,respectively.The transcriptome data of A.hypogaea roots with non-infected or infected by J2s were analyzed.Results:The J2s could approach and infect inside of A.hypogaea root tips,and the chemotactic migration rate and infestation rate were 20.72%and 22.50%,respectively.Differential gene expression and pathway enrichment analyses revealed ubiquinone and other terpenoid-quinone biosynthesis pathway,plant hormone signal transduction pathway,and phenylpropanoid biosynthesis pathway in A.hypogaea roots responded to the infestation of M.incognita.Furthermore,the AhHPT gene,encoding homogentisate phytyltransferase,was considered to be an ideal candidate gene due to its higher expression based on the transcriptome data and quantitative real-time PCR analysis.Conclusion:Therefore,the key gene AhHPT might be involved in the A.hypogaea against M.incognita.These findings lay a foundation for revealing the molecular mechanism of A.hypogaea resistance to M.incognita and also provide a prerequisite for further gene function verification,aiming at RKN-resistant molecular breeding.

Resistance Evaluation of Capsicum spp. Germplasm to Meloidogyne incognita

[Objective] This study aimed to screen out hot pepper germplasms highly resistant to Meloidogyne incognita, thereby providing resistant resources for hot pep- per breeding. [Method] Comprehensive analysis combining cluster analysis and sub- ordinate function was conducted through determining related resistance indexes of 67 hot pepper germplasms 50 days after inoculated with M. incognita. [Result] The effects of M. incognita on related resistance indexes were significantly different am- ong the hot pepper germplasms. Egg index and gall index had abundant genetic variation with variation coefficients of 143.16% and 118.95%, respectively. Based on the gall indexes, cluster analysis of hot pepper germplasms was performed. The 67 hot pepper germplasms were divided into 4 groups （resistant, moderately resistant, susceptible and high susceptible）. The resistance intensity of the hot pepper germplasms were ranked according to the sum of subordinate function values of various resistance indexes. The total function values of Rela 2 and L506M were the largest （2.00）, indicating that these two germplasms were immune to M. incognita. The total function values of L287-2, L522-1M, L504M, L515-2, 13SM100-1, L512M, L292-1, L319, L316, L317, 13SM87-1 and Rela 5 were larger than 1.95, indicating that these germplasms were highly resistant to M. incognita. [Conclusion] This study could provide certain resistant resources for resistance breeding of hot pepper to M. incognita.

新颖杀线虫剂MCW-2对爪哇根结线虫(Meloidogyne javanica)的防治活性

随着甲基溴等高效土壤熏蒸剂以及非熏蒸杀线虫剂的退出或禁用,当前线虫的防治难度日益加大。由于杀线虫剂市场小于除草剂、杀菌剂和杀虫剂,许多农化企业认为开发新颖杀线虫剂无利可图。此外,对人类与非靶标生物安全的有效物质的开发可行性极低。目前,广泛应用的杀线虫剂有涕灭威、硫线磷、克百威、丙线磷、苯线磷、噻唑磷、

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

Studies were conducted under pot conditions to determine the comparative efficacy ofcarbofuran 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 carbofuran and A. indica seed powder increased plant growth to untreated inoculated plants. Analysis of data showed that 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.

Evaluation of Chinese rice varieties resistant to the root-knot nematode Meloidogyne graminicola

The root-knot nematode Meloidogyne graminicola, which is distributed worldwide, is considered a major constraint on rice production in Asia. The present study used the root gall index and number of nematodes inside the roots to evaluate resistance/susceptibility to M. graminicola in different subpopulations of Oryza sativa （aus, hybrid aus, indica, hybrid indica, temperate japonica, tropical japonica）. Nematode development in highly resistant varieties was also evaluated. Analyses of randomly selected 35 varieties showed the number of M. graminicola nematodes inside the roots correlated very strongly （r=0.87, P≤0.05） with the nematode gall index, and the results from pot and field experiments revealed similar rankings of the varieties for resistance/susceptibility. Among the 136 tested varieties, temperate japonica displayed the highest gall index, followed by tropical japonica, indica, hybrid indica, aus, and hybrid aus. Zhonghua 11 （aus）, Shenliangyou 1 （hybrid aus） and Cliangyou 4418 （hybrid indica） were highly resistant to M. graminicola under both pot and field conditions. Further examination of nematode development suggested that compared to susceptible rice, M. graminicola penetrated less often into highly resistant varieties and more frequently failed to develop into females. The promising varieties found in the present research might be useful for the breeding of hybrid rice in China and for the further development of practical nematode management measures.

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

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.

Field evaluation of Streptomyces rubrogriseus HDZ-9-47 for biocontrol of Meloidogyne incognita on tomato

Streptomyces rubrogriseus HDZ-9-47,isolated from eggs of Meloidogyne spp.,was evaluated as a potential biocontrol agent of Meloidogyne incognita under in vitro and protective field.Microscopic observations showed that HDZ-9-47 parasitized eggs of M.incognita within 7 days.In vitro,the culture filtrate of HDZ-9-47 caused 97.0%mortality of second-stage juveniles（J2s）of M.incognita and inhibited more than 50%egg hatching.In the field,compared with the control,the rootknot index and J2s density in the treatment of drench the broth contained 1012 HDZ-9-47 spores were respectively reduced by 51.1 and 80.7%at 90 days post transplantation,which were better than that in other application doses and methods.In addition,reduction rates of root-knot index and J2s density of the treatment of combined application of HDZ-9-47 with biofumigation was 87.1 and 91.0%,respectively,better than either of HDZ-9-47 or biofumigation used alone or fosthiazate treatment.And tomato yield also increased by 16.1%.Together,our results suggest that HDZ-9-47 could be an effective biocontrol agent of M.incognita,and that application of HDZ-9-47 combined with cabbage residue biofumigation was a promising and sustainable option for M.incognita control.

Sources for Heat-Stable Resistance to Southern Root-Knot Nematode (Meloidogyne incognita) in Solanum lycopersicum

Southern root-knot nematode （Meloidogyne incognita） is a major problem in vegetable production in China due to the expansion of plastic tunnel and solar greenhouse. Using resistant cultivars is an effective approach to control the disease. Nine genes, Mi-1 to Mi-9, have been reported and only Mi-1 has been successfully used in tomato breeding. However, Mi-1 is inactive at a temperature above 28~C. In order to identify sources for heat-stable resistance to southern root-knot nematode, 53 genotypes of tomato （Solarium spp.） were inoculated with an isolate of M. incognita in the growth chamber at 28 or 32℃ for initial screening. 28 lines had less than 25 galls and were considered as resistant candidates. The top 60% （16 in total） of resistant candidates obtained from each temperature were subject to re-evaluation at 32~C using the same nematode isolate. Three lines ZN17, ZN 48, and LA0385 showed heat-stable resistance with an average of 10 galls or less per plant. LA0385 is a wild species, while ZNI7 and ZN48 are elite breeding lines. These lines were grown in a greenhouse for two seasons, and also showed high resistance with less than 10 galls per plant. Thus they were considered as good sources for breeding resistance to southern root-knot nematode in tomato.

Evaluation of the biocontrol potential of Aspergillus welwitschiae against the root-knot nematode Meloidogyne graminicola in rice(Oryza sativa L.)

The root-knot nematode Meloidogyne graminicola is considered one of the most devastating pests in rice-producing areas,and nematicides are neither ecofriendly nor cost effective.More acceptable biological agents are required for controlling this destructive pathogen.In this study,the biocontrol potential of Aspergillus welwitschiae AW2017 was investigated in laboratory and greenhouse experiments.The in vitro ovicidal and larvicidal activities of A.welwitschiae metabolites were tested on M.graminicola in laboratory experiments.The effect of A.welwitschiae on the attraction of M.graminicola to rice and the infection of rice by M.graminicola was evaluated in a greenhouse.The bioagent AW2017 displayed good nematicidal potential via its ovicidal and larvicidal action.The best larvicidal activity was observed at a concentration of 5×AW2017,which caused an 86.2%mortality rate at 48 h post inoculation.The highest ovicidal activity was recorded at a concentration of 5×AW2017,which resulted in an approximately 47.3%reduction in egg hatching after 8 d compared to the control.Under greenhouse conditions,the application of A.welwitschiae significantly reduced the root galls and nematodes in rice roots compared to the control.At a concentration of 5×AW2017,juveniles and root galls in rice roots at 14 d post inoculation(dpi)were reduced by 24.5 and 40.5%,respectively.In addition,the attraction of M.graminicola to rice roots was significantly decreased in the AW2017 treatment,and the development of nematodes in the AW2017-treated plants was slightly delayed compared with that in the PDB-treated control plants.The results indicate that A.welwitschiae is a potential biological control agent against M.graminicola in rice.

Potassium sulphate induces resistance of rice against the rootknot nematode Meloidogyne graminicola

Potassium(K),an important nutrient element,can improve the stress resistance/tolerance of crops.The application of K in resisting plant-parasitic nematodes shows that the K treatment can reduce the occurrence of nematode diseases and increase crop yield.However,data on K_(2)SO_(4)induced rice resistance against the root-knot nematode Meloidogyne graminicola are still lacking.In this work,K_(2)SO_(4)treatment reduced galls and nematodes in rice plants and delayed the development of nematodes.Rather than affecting the attractiveness of roots to nematodes and the morphological phenotype of giant cells at feeding sites,such an effect is achieved by rapidly priming hydrogen peroxide(H_(2)O_(2))accumulation and increasing callose deposition.Meanwhile,galls and nematodes in rice roots were more in the potassium channel OsAKT11 and transporter OsHAK5 gene-deficient plants than in wild-type,while the K_(2)SO_(4)-induced resistance showed weaker in the defective plants.In addition,during the process of nematode infection,the expression of jasmonic acid(JA)/ethylene(ET)/brassinolide(BR)signaling pathway-related genes and pathogenesis-related(PR)genes OsPR1 a/OsPR1 b was up-regulated in rice after K_(2)SO_(4)treatment.In conclusion,K_(2)SO_(4)induced rice resistance against M.graminicola.The mechanism of inducing resistance was to prime the basal defense and required the participation of the K^(+)channel and transporter in rice.These laid a foundation for further study on the mechanism of rice defense against nematodes and the rational use of potassium fertilizer on improving rice resistance against nematodes in the field.

Morphological and molecular characterization of the rice root-knot nematode, Meloidogyne graminicola, Golden and Birchfeild, 1965 occurring in Zhejiang, China

The rice root-knot nematode Meloidogyne graminicola is a severe pest of rice. In China, it was first reported from Hainan Province, and later from several other provinces. In the present study, a rice root-knot nematode population found from the rice cultivation areas of Zhejiang Province, China is characterized via molecular analysis using internal transcribed spacer(ITS) and cytochrome c oxidase subunit Ⅱ(coxⅡ)-16 S rRNA genes and scanning electron microscopy(SEM) observations of males and the second-stage juveniles. Morphometric data and molecular sequence comparisons for all M. graminicola populations occurring in China are also provided. The overall morphology of M. graminicola found in Zhejiang match well with the original description, though males have a slightly longer body and stylet, and a shorter tail, while the second-stage juvenile is also slightly longer than in the original description. This is the first report of M. graminicola from Zhejiang. Phylogenetic studies based on coxⅡ suggest that all the Chinese populations belong to Type B. This study expands knowledge of the increasing distribution and phylogenetic relationships of M. graminicola that occur in China.

Determination of Nematicidal Effects of Some Biopesticides against Root-Knot Nematode （Meloidogyne incognita） on Kiwifruit

The aim of this study was to determine the nematicidal effects of some biopesticides againist root-knot nematodes （RKNs） （Meloidogyne incognita） on Bruno type kiwifruit seedlings. Research was conducted in the Atattirk Central Horticultural Research Institute （ACHRI, Yalova, Turkey） greenhouse during 2013-2014. Biopesticides observed in this study were： sesame oil （Devalone EC）, castor oil （Ricinus communis）, Myrothecium verrucaria （M. verrucaria strain AARC-0255, Inferno DF）, Glomus spp. （Endomycorrhizal fungi, Endo Roots Soluble SP） and Paecilomyces lilacinus （Entomopathogenic fungi, P. lilacinus strain PL1, Bionematon SL）. Nematicide Nemacur EC 400 （fenamiphos） was used as treated control （TC） and trials were set up as randomized parcel design （RPD） with seven characters and 10 replicates. Reproduction ratio was determined according to scale values in trial applications and second stage juvenile （J2） populations of M. incognita in soil. The results showed that the best nematicidal effects against RKNs were determined in castor oil （77.92% in 2013 and 73.61% in 2014） and P. lilacinus （61.03% in 2013 and 55.55% in 2014）.

温度对南昌市郊区南方根瘿线虫(Meloidogyne incognita)发育的影响

一、前言寄生于植物并导致严重病害的根瘿线虫(Meoloidogyne)是变温动物。了解这类动物二期幼虫侵入寄主植物之后的发育起点温度及达到性成熟而产卵所需的有效积温,不但在理论上而且在生产上都有重要意义。然而有关这方面的文献不多,提出过报告的作者有Tyler(1933)乌斯基诺夫,Milne和Plessis(1964),Starr和mai(1976),Bird和Milln(1979)。南昌市郊侵害多种蔬菜作物的根瘿线虫是M.incognita,值得注意的是,上述作者中只有Bird和Milln在澳大利亚对这个种进行过观察。该作者的观察结果是否适合于南昌市郊这个居群?我们在防治实践中应该认定的数据是什么?问题必须予以回答。

RNAi of <i>MiASB</i>caused high mortality of <i>Meloidogyne incognita</i>juveniles and inhibited the nematode disease

The southern root-knot nematode, Meloidogyne incognita, is one of the most prevalent and damaging plant-parasitic nematodes in the world and causes serious damages to agricultural production. We cloned a mitochondrial ATP synthase b subunit gene fragment of M. incognita (MiASB) based on the nematode genomics prediction. By soaking in the MiASB dsRNA solution, the hatching of RNAi treated eggs was reduced by 60% compared to negative control and by 64% compared to untreated control. Mortality of RNAi treated second stage juvenile (J2) was 8.6 times higher than that of negative control and 26 times higher than the untreated control. Inoculating the RNAi treated egg masses and J2 to tomato seedlings showed the pathogencity was significantly reduced. For the RNAi treated egg masses, the amount of root galls on silence treated seedlings was reduced by 92% compared to that on the negative control seedlings, and reduced by 93% compared to that on untreated control seedlings. For the treated J2, the amount of root galls on silence treated seedlings was reduced by 83% and 86% compared to negative and untreated control seedlings, respectively. The study revealed the MiASB silence had a positive effect on prevention and control of root-knot nematode disease, and also showed that the MiASB may be involved in the pathogenesis of nematode, which provided new ideas and ways to the research of nematode pathology and nematode disease control.