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.

Control of Southern Root-knot Nematodes on Tomato and Regulation of Soil Bacterial Community by Biofumigation with Zanthoxylum bungeanum Seed

Biofumigation is an environmentally friendly strategy used to control nematodes and plant diseases.The volatile oil of Zanthoxylum bungeanum has high insecticidal and antibacterial activity.However,it is not known if the seed of Z.bungeanum is a suitable material for biofumigation to control southern root-knot nematodes(SRKN)on tomato,and how it may regulate the soil bacterial community structure.We used pot experiments in the greenhouse to determine the effects of Z.bungeanum seeds on SRKN,plant growth parameters,soil physicochemical and microbial characteristics.A total of 26 volatile components,including nematicidally active substances,were identified from Z.bungeanum seeds.Z.bungeanum seed biofumigation significantly reduced the SRKN population by 88.89%and 81.55%on the 50th and 100th day after transplanting,respectively.Compared to the control,the total soluble sugar,soluble solids,soluble protein,titratable acid,root activity and the fruit yield per tomato plant increased significantly.The content of soil alkali-hydrolyzed nitrogen,available potassium and the soil enzyme activities were also significantly increased.The soil bacterial diversity and the co-occurrence network complexity were increased by Z.bungeanum seed biofumigation.Relativelymore keystone OTUs in biofumigation soil had potential plant growth-promoting capabilities.The function of Z.bungeanum seed increasing tomato production in SRKN-infected soil depends on directly killing SRKN and improving soil properties.These results indicate that Z.bungeanum seed can be used as both a nematicide and a high quality organic fertilizer in tomato production.

Preparation and efficacy evaluation of Paenibacillus polymyxa KM2501-1 microbial organic fertilizer against root-knot nematodes

Root-knot nematodes(RKNs) cause huge yield losses to agricultural crops worldwide. Meanwhile, livestock manure is often improperly managed by farmers, which leads to serious environmental pollution. To resolve these two problems, this study developed a procedure for the conversion of chicken manure to organic fertilizer by larvae of Hermetia illucens L. and Bacillus subtilis BSF-CL. Chicken manure organic fertilizer was then mixed thoroughly with Paenibacillus polymyxa KM2501-1 to a final concentration of 1.5×10^(8)CFU g^(-1). The efficacy of KM2501-1 microbial organic fertilizer in controlling root-knot nematodes was evaluated in pot and field experiments. In pot experiments, applying KM2501-1 microbial organic fertilizer either as a base fertilizer or as a fumigant at the dose of 40 g/pot suppressed root-knot disease by 61.76 and 69.05% compared to the corresponding control treatments, respectively. When applied as a fumigant at the dose of 1 kg m;in field experiments, KM2501-1 microbial organic fertilizer enhanced the growth of tomato plants, suppressed root-knot disease by 49.97%, and reduced second stage juveniles of RKN in soil by 88.68%. KM2501-1 microbial organic fertilizer controlled RKNs better than commercial bio-organic fertilizer in both pot and field experiments. These results demonstrate that this co-conversion process efficiently transforms chicken manure into high value-added larvae biomass and KM2501-1 microbial organic fertilizer with potential application as a novel nematode control agent.

Toxicity Test of Different Pesticides on Tobacco Root-knot Nematodes

[Objectives]This study was conducted to quickly screen out effective and safe agents for controlling tobacco root knot nematode disease.[Methods]Six pesticides were tested and screened indoors at five different concentrations.[Results]The six pesticides all had toxic effects on the second-instar larvae of tobacco root-knot nematode,and the corrected mortality was positively correlated with the concentration and time of the pesticides,with the correlation coefficients above 0.8.From the perspective of inhibitory activity,the order was fosthiazate>abamectin>emamectin benzoate>cadusafos>ethoprophos>carbosulfan.Four pesticides that can be used in the field were selected.[Conclusions]This study provides a theoretical basis for field pesticide selection.

Occurrence of Root-Knot and Reniform Nematodes in Ornamental Plants Grown in Aligarh Muslim University Campus, India

An extensive survey of about 50 ornamental plants growing in A.M.U. campus were carried out to find out the infection of root-knot (Meloidogyne spp.) and reniform nematodes (Rotylenchulus reniformis). Out of 50 species of ornamental plants studied, 29 species of these plants were found to be infected with root-knot nematodes (Meloidogyne spp.) and 15 species were infected with reniform nematode (Rotylenchulus reniformis). The highest percentage of infection of root-knot nematodes was observed in Impatiens balsamina (100%) and reniform nematode was observed in Hibiscus rosa-sinensis (56%). Among the Meloidogyne spp. the highest percentage of infection of M. incognita was observed in Pseuderanthemum atropurpureum (80%) whereas, the highest percentage of infection of M. javanica and M. arenaria was observed in Mirabilis jalapa (72%) and Celosis cristata (28%).

The synergistic advantage of combining chloropicrin or dazomet with fosthiazate nematicide to control root-knot nematode in cucumber production

The highly-damaging root-knot nematode(Meloidogyne spp.,RKN)cannot be reliably controlled using only a nematicide such as fosthiazate because of increasing pest resistance.In laboratory and greenhouse trials,we showed that chloropicrin(CP)or dazomet(DZ)synergized the efficacy of fosthiazate against RKN.The combination significantly extended the degradation half-life of fosthiazate by an average of about 1.25 times.CP or DZ with fosthiazate reduced the time for fosthiazate to penetrate the RKN cuticle compared to fosthiazate alone.CP or DZ combined with low or medium rate of fosthiazate increased the total cucumber yield,compared to the use of each product alone.A low-dose fosthiazate with DZ improved total yield more than a low dose fosthiazate with CP.Extending the half-life of fosthiazate and reducing the time for fosthiazate or fumigant to penetrate the RKN cuticle were the two features that gave the fumigant-fosthiazate combination its synergistic advantage over these products used singularly.This synergy provides the opportunity for farmers to use a low dose of fosthiazate which lowers the risk of RKN resistance.Farmers could combine DZ at 30 g m^-2 with fosthiazate at a low rate of 0.375 g m^-2 to control RKN and adequately control two major soil-borne diseases in cucumber greenhouses.

Effects of Two Composted Plant Pesticide Residues,Incorporated with Trichoderma viride,on Root-Knot Nematode in Balloonflower

Plant pesticide residues, such as chinaberry （Melia toosendan） residue and sand cypress （Sabina vulgaris） residue, are pesticidal plant materials discarded after the bioactive ingredient has been extracted with organic solvents. The only option for botanical pesticide residue utilization has been as landfill. Chinaberry residue （CBR） and sand cypress residue （SCR） were collected and composted in Yangling, Shaanxi Province, China. We studied the effects of chinaberry residue compost （CBRC）, CBRC incorporated with Trichoderma viride （CBRCT）, sand cypress residue compost （SCRC）, and SCRC incorporated with T. viride （SCRCv） on the root-knot nematode, Meloidogyne incognita, infesting the balloonflower （Platycodon grandiflorum）. Bioassay results indicated that stock solutions of the CBRCT and SCRCT extracts significantly inhibited egg hatching and caused high larval mortality, followed in degree by the CBRC and SCRC extracts. The CBR and SCR extracts caused very low inhibition of eggs and larvae. Supplementing potting mixtures with these four composts reduced the severity of root galling and increased the proportion of marketable roots. The severity of root galling decreased and the average weight of the marketable roots increased with an increase in all the composts when supplemented at rates from 5 to 30%. CBR- and SCR-supplemented pot soils also inhibited the nematodes, but CBR and SCR applied to the soil had a phytotoxic effect and inhibited balloonflower growth. Supplementing field soil with the composts reduced the severity of root galling and the populations of southern root-knot nematodes in the soil. CBRCT and SCRCT clearly enhanced the average weight of the marketable roots by 30.45 and 26.64%, respectively. Continuous supplementation with CBRCT or SCRCT in the same field significantly enhanced the control of the root-knot nematode, and the populations of nematodes continued to decrease with second inoculations. The populations of total Trichoderma spp. were distinctly enhanced and were maintained at high levels for a long time in the supplemented soils.

Morphology and Molecular Identification of Root-knot Nematode in Partial Tobacco-growing Areas in Yunnan Province

[Objectives]The species and distribution of root-knot nematodes in tobacco growing regions of Yunnan were investigated,in order to provide reference for comprehensive prevention of root-knot nematodes disease and tobacco variety layout. [Methods]Fifty-four samples of root-knot nematode host on tobacco crops were collected from Kunming,Qujing and Yuxi cities in Yunnan from August to October in 2015. The species of root-knot nematodes were identified by observing perineal patterns and molecular biological testing（ PCR of ribosomal DNA of ITS region and sequence characterized amplified region,SCAR）. [Results] There were 24 samples belonging to Meloidogyne arenaria,accounting for 44. 44%; seven M. incognita samples,accounting for 12. 96%; one M. javanica sample,accounting for 1. 85%. Eleven samples were compound populations of M. javanica and M. arenaria,accounting for 20. 37%. Five were compound populations of M. incognita and M. arenaria,accounting for 9. 26%. Three were compound populations of M. incognita and M. javanica,accounting for 5. 56%. Three belonged to compound population of M. incognita,M. javanica and M. arenaria,accounting for 5. 56%. [Conclusions] The species of root-knot nematodes in tobacco growing areas of Yunnan mainly include M. incognita,M. javanica and M. arenaria. M. arenaria is the dominant population.

Bacterial artificial chromosome library construction of root-knot nematode resistant pepper genotype HDA149 and identification of clones linked to Me3 resistant locus

Pepper （Capsicum annuum. L.） is a widely cultivated vegetable crop worldwide and has the second largest planting area and the first largest vegetable output and value in China. Pepper root-knot nematode （Meloidogyne spp.） is one of the most serious pests of pepper, which caused huge losses every year. Previous studies showed that the Me3 gene is resistant to a wide range of Meloidogyne species, including M. arenaria, M. javanica, and M. incognita. HDA149, a double haploid pepper genotype, harboring the root-knot nematode resistance gene Me3, was used to construct bacterial artificial chro- mosome library （BAC） via the vector of CopyControFM pCC1 in this study. The library consists of 210 200 BAC clones and is equivalent to 5.3 pepper genomes. The average insert size is 95 kb, and most of them are 90-120 kb; but the empty clones are less than 3%. In order to screen the BAC library easily, 550 super pools with 384 BAC clones of each pool were further developed in this study. Specific primers from Me3 gene locus were used for BAC library screening, and more than 20 positive BAC clones were obtained. Then the selected positive BAC clones were analyzed by restriction enzyme digestion, BAC-end sequencing, marker development, and new positive BAC clones exploration, respectively. Finally, the contig with total length of about 300 kb linked to the Me3 locus was constructed based on chromosome walking strategy, which made a solid foundation for the cloning of the important root-knot nematode resistance gene Me3.

Preliminary Study on Mixed Use of Agaricus bisporus Residue and Microbial Agent to Control Cucumber Root-knot Nematode

Single or mixed use ofAgaricus bisporus residue and microbial agent had better control effect on cucumber root-knot nematode disease in greenhouse. The results showed that the control effect of single use of A. b/sporus residue was 32.9% - 34.7%, and the yield increasing rate was 2.1% - 8.7% ; the control effect of mixed use ofA. b/sporus residue and microbial agent was 59. 1% - 63. 6%, and yield increasing rate was 2.6% - 3.5%. The experimental dose had no ad- verse effects on soil physical and chemical properties. The mixed use of A. b/sporus residue and microbial agent was one of the effective ways to control root-knot nematode disease.

Genetic Mapping of Root-knot Nematode Resistance Genes in Solanaceous Vegetables

Root-knot nematodes are becoming more and more harmful to solanaceous vegetables. The most economical and effective way to deal with root-knot nematode disease is to breed varieties with disease resistance. This paper reviewed the recent research progress and achievements of tomato, pepper, eggplant and potato on root-knot nematode disease resistance gene characteristics, disease resistance gene mapping and disease resistance gene molecular markers, and prospects for future research directions.

广西水稻产区稻-菜轮作田水稻根结线虫病发生情况调查及病原鉴定

为了明确广西水稻产区稻-菜轮作田根结线虫发生情况及其病原分类地位,在广西14个市27个乡(镇)的171块水稻产区稻-菜轮作田进行了采样调查,并进行致病线虫分离,根据2龄幼虫形态、雌虫会阴花纹特征等,结合核糖体ITS区和28S rDNA D2D3区序列分析方法对病原线虫种类进行鉴定。结果表明,共有64个田块发生根结线虫为害,水稻种植季根结线虫检出率为37.4%,蔬菜轮作季根结线虫检出率为25.7%。广西水稻根结线虫病病原为拟禾本科根结线虫Meloidogyne graminicola。说明拟禾本科根结线虫病在广西稻-菜轮作田发生已经相当普遍,应当引起重视。

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.

福建省土源性线虫感染流行现状分析

目的了解福建省土源性线虫人群感染现状。方法2007-2009年对全省9个地市采用分层整群随机抽样的方式确定调查点,调查对象为3周岁以上常住居民。用Kato-Katz法(一粪一检)粪检蛔虫、钩虫和鞭虫虫卵,分别计算3种虫卵的每克粪便虫卵数(EPG),同时收集调查者的性别、年龄和受教育程度等。并将本次调查结果与1992年和2003年的调查结果进行比较分析。结果本次共调查了9地市49县(市、区)185乡(镇)610村的93 833人。土源性线虫总感染率为10.14%(9 511/93 833),与1992年和2003年的比较,分别下降了86.88%和71.84%。蛔虫、钩虫和鞭虫的感染率分别为1.32%(1 234/93 833)、7.31%(6 863/93 833)和1.73%(1 622/93 833)。蛔虫、钩虫和鞭虫感染者的平均EPG分别为9 556、526和156。男性和女性感染率分别为9.48%(4 385/46 246)和10.77%(5 126/47 587),性别间差异有统计学意义(χ2=42.84,P<0.01);各年龄组间感染率差异有统计学意义(χ2=1 626,P<0.01);不同教育程度的人群感染率不同,教育程度越高,感染率越低(χ2=1 107,P<0.01)。结论福建省土源性线虫感染率呈下降趋势,但是在经济欠发达地区感染率仍然较高,钩虫感染率仍高于全国平均水平。

北京地区奶牛寄生虫感染情况的调查

为了了解北京地区奶牛胃肠道寄生虫感染情况,采集北京地区成年牛和犊牛的粪样,用饱和盐水漂浮法、水洗沉淀法对粪样进行了定性检查,用麦克马斯特计数法对线虫卵和球虫卵囊进行了定量检查。结果发现,北京地区成年奶牛和犊牛粪样中检出的主要是线虫卵和球虫卵囊,未检出吸虫卵。成年奶牛粪样中线虫卵的阳性率为14.64%,平均EPG值范围为190~853,并在5~9月份出现一个比较明显的高峰期;球虫卵囊阳性率为49.15%,平均OPG值范围为125~346,高峰出现在5~11月份。犊牛粪样中线虫卵的阳性率为24.56%,平均EPG值范围为305~1 053,并在5~11月份出现一个比较明显的高峰期;粪样中球虫卵囊阳性率为65.02%,平均OPG值范围为2 540~7 648,并在7月份出现一个高峰。根据调查结果,对北京地区奶牛寄生虫病防治提出了建议。

广西香蕉植物线虫病发生情况调查

作者于2009-2010年,对广西香蕉线虫病发生情况进行了实地调查,分别采集根际土壤和根系样本共253份,调查结果表明:广西香蕉主要有害线虫有根结线虫、矮化线虫、短体线虫、肾状线虫、螺旋线虫、滑刃线虫、纽带线虫、垫刃线虫和小环线虫,其中根结线虫发生最普遍也最严重,根结病指最高达60,土壤根结线虫虫口密度最高达307头/100mL土。

福建省人体肠道线虫感染现状调查

目的了解福建省人体肠道线虫的流行现状。方法采用分层整群随机抽样的方法,对13个中签县市39个村(点)进行调查。应用Kato-Katz涂片法,检查粪便中肠道线虫卵;胶带纸肛拭法,检查12岁以下儿童的蛲虫感染。结果粪检20 195人,感染者7 272人,总感染率为36．01％。其中,男性感染率34．39％,女性感染率37．53％;蛔虫、钩虫、鞭虫感染率分别为9．55％、19．73％与11．48％,蛲虫为22．06％(817／3703)。年龄组以60～65岁组感染率最高占48．98％,职业分布以农民最高占41．56％,地区分布以闽北片区的凹头村最高占 79．09％。结论各地区、各种寄生虫感染率、感染度呈总体下降趋势,但各地起伏较大,部分县市钩虫感染率居高不下,肠道线虫感染仍然是当前农村地区普遍存在的公共卫生问题之一。

广西靖西县旱地烟草根结线虫病发生情况调查及防治措施

2007～2008年对广西靖西县15个乡镇的旱地烟草根结线虫病发生情况进行了实地调查,结果显示,靖西县15个乡镇旱地烟草根结线虫检出率为100%,其中龙临乡的根结线虫量最多,达989头/100mL土;平均根结指数为17.34,其中最高的是南坡乡,达46.89,表明根结线虫病在靖西县旱地烟草中发生普遍。文章同时分析了靖西县普遍发生烟草根结线虫病的原因,并提出了防治措施。

河南省人群肠道线虫感染情况

本文报告本省人群的肠道线虫感染情况。按全国人体寄生虫分布调查实施细则的要求与方法，对本省３９个县、市１６４个点的人群进行调查。共检查８５５５５人，查见线虫感染者４８１３４例，其感染率为５６．３％。查见线虫７种，人群各种线虫的感染率分别为蛔虫４１．４％、钩虫２０．７％、鞭虫８．２％、东方毛圆线虫０．０１％、粪类圆线虫０．０３％和节结线虫１例。男、女人群的蛔虫、鞭虫及钩虫的感染率依次为３６．３％和４３．４％、８．１％和８．４％、２１．８％和１９．５％。蛔虫和钩虫为本省肠道线虫的重点虫种。１５岁以下的儿童、少年是蛔虫感染的重点人群，１６岁以上者是钩虫感染的重点人群。

中国四省(区)葡萄根围螺旋线虫种类记述

描述了采自陕西、山东、广西、宁夏 4省 (区 )葡萄根际的 6种螺旋属线虫 :双宫螺旋线虫 (Helicotylenchusdi hystera)、外异螺旋线虫 (H exallus)、双角螺旋线虫 (H .digonicus)、H .digitiformis、H .platyurus、H .multicinc tus。其中后