Pathogenicity of the root-knot nematode Meloidogyne javanica on potato

Host–parasite relationships and pathogenicity of Meloidogyne javanica on potatoes (newly recorded from Malta) were studied under glasshouse and natural conditions. Potato cvs Cara and Spunta showed a typical susceptible reaction to M. javanica under natural and artificial infections, respectively. In potato tubers, M. javanica induced feeding sites that consisted of three to four hypertrophied giant cells per adult female. Infection of feeder roots by the nematode resulted in mature large galls which usually contained at least one mature female and egg mass. In both tubers and roots, feeding sites were characterized by giant cells containing granular cytoplasm and many hypertrophied nuclei. Cytoplasm in giant cells was aggregated alongside the thickened cell walls. Stelar tissues within galls appeared disorganized. The relationship between initial nematode population density ( P ) [0–64 eggs + second-stage juveniles (J2s) per cm³ soil] and growth of cv. Spunta potato seedlings was tested under glasshouse conditions. A Seinhorst model [ y = m  + (1 −  m ) z ^{( P − T )}] was fitted to fresh shoot weight and shoot height data of nematode-inoculated and control plants. Tolerance limits ( T ) for fresh shoot weight and shoot height of cv. Spunta plants infected with M. javanica were 0·50 and 0·64 eggs + J2s per cm³ soil, respectively. The m parameter in that model (i.e. the minimum possible y -values) for fresh shoot weight and shoot height were 0·60 and 0·20, respectively, at P  = 64 eggs + J2s per cm³ soil. Root galling was proportional to the initial nematode population density. Maximum nematode reproduction rate was 51·2 at a moderate initial population density ( P  = 4 eggs + J2s per cm³ soil).     

酸黄瓜南方根结线虫病抗性的解剖学及其细胞学研究

为探明酸黄瓜南方根结线虫病抗性的内在机理,以抗病材料酸黄瓜与感病材料北京截头为试材,对南方根结线虫侵入与幼虫发育、根的解剖学及线虫侵入诱导形成的取食位点的细胞学结构进行了比较研究。结果表明,抗病材料酸黄瓜根系中线虫侵入率极显著低于感病材料北京截头(P0.01),酸黄瓜能够有效抵抗南方根结线虫的侵入;抗、感材料根系中雌雄虫个体比例分别为1∶12和1∶5(P0.01),抗性反应能够抑制线虫取食和幼虫发育;酸黄瓜根的解剖结构与普通栽培黄瓜相似,酸黄瓜的根不具有结构抗性;抗病反应中细胞发生过敏性坏死,感病反应中无此类现象发生。抗侵入、抑制取食和坏死反应是抗病材料酸黄瓜抗性反应的主要特征。     

设施黄瓜根结线虫化学防治技术研究

为了探索简便、安全、高效防控蔬菜根结线虫技术,更好地指导设施蔬菜生产,进行了98.1%1,3-二氯丙烯·氯化苦胶囊剂不同剂量、不同施药深度、施药后覆膜与否和定植前后施药对设施蔬菜根结线虫的防治效果研究。结果表明,用98.1%1,3-二氯丙烯·氯化苦胶囊剂20kg/667m~2进行土壤熏蒸处理,闷棚后定植优于定植后施药处理,施药后覆膜优于不覆膜处理对蔬菜根结线虫的防治效果,不同施药深度对根结线虫的防治效果没有明显差异,本研究对于设施蔬菜根结线虫防治措施的制定具有重要的指导意义。     

Detection of the root-knot nematode Meloidogyne ethiopica in Greece

Root-knot nematodes (RKN), Meloidogyne spp., are very significant in agriculture because they can be found almost everywhere and have a wide host range. In summer 2009, two soil samples from maize and kiwi crops, from the area of Kavalla in North Greece, were analyzed for the presence of nematodes. RKN were detected in both samples and identified as M. ethiopica on the basis of biochemical (esterases) and sequence data (18S rDNA). Meloidogyne ethiopica poses a significant threat to farmers in Greece and the establishment and spread of this species has to be controlled. This is the first report of M. ethiopica in Greece and the second report of this species for Europe.     

In-plant activation of root-specific expression of a cytotoxic gene disrupts the development of the root-knot nematode,Meloidogyne javanica

Plant hosts can be engineered to disrupt the development of sedentary plant-parasitic nematodes or proper functioning of the feeding sites the nematodes induce. The use of constitutive promoters to express dsRNAs or nematode inhibitor proteins may be unreliable because of possible silencing or yield penalty from continuous expression in a plant host. This ill-effect can be avoided if a root-specific, nematode-responsive promoter (NRP) is used to drive the target nematode-inhibitory message. This study used the In Plant Activation (INPACT) system to express a barstar-controlled barnase in galls of Meloidogyne javanica and assessed how the engineered tobacco lines affected the growth and development of the nematodes. Of the 11 combinations of four NRPs and the CaMV 35S promoter assessed, the AtCel1 and TobRB7 combinations activated specific expression of split β-glucuronidase (GUS) and barnase genes in and around giant cells. The same NRP combination directed expression of the barnase gene in tobacco roots also constitutively expressing the barstar gene (SPBB transgenic lines). On roots of six T₁ SPBB lines, there was up to 94% reduction in the number of galls with significantly smaller adult females compared to those on wild-type plants. Some of the females on lines SPBB4-1 and SPBB-4-2, for example, were not associated with galls. The results indicated the engineered plants disrupted M. javanica development and demonstrate the potential for controlled and localized expression of peptides, such as those that could block specific effectors, to disrupt initiation, formation, establishment, or proper functioning of feeding cells induced by damaging sedentary nematodes.     

根结线虫食道腺细胞表达的基因及其应用潜力

根结线虫是国际公认的最为重要的植物病原线虫,研究其食道腺细胞表达的基因是了解其寄生性和致病性的基础。近年来国际上已从根结线虫食道腺细胞分离基因22个,其基因产物主要包括β 1,4内切葡聚糖酶、果胶酸裂解酶、分支酸变位酶、钙网蛋白、类毒液过敏蛋白等。本文对上述工作的研究进展作简要评述,并对今后的应用潜力进行了讨论。     

Control of root-knot nematodes (Meloidogyne spp.) in Hungary1

Under Hungarian climatic conditions, root-knot nematodes, and other phytoparasitic nematodes, generally cause damage in certain plant growing areas. These pests are present in glasshouses throughout the country. In the field the nematodes occur in sandy soil in the vegetable-growing areas of southern and central Hungary. The following species of root-knot nematodes have so far been reported to occur in Hungary: Meloidogyne incognita, M. arenaria, M. hapla, M. javanica, M. incognita acrita, M. thamesi and M. naasi. There are 10 specific nematicides registered for nematode control in the country. These chemicals are mainly applied in glasshouses where their use produces most economic return. Nematoderesistant cultivars are only available in the case of tomato. The nematodes cause the heaviest damage on glasshouse cucumber.     

植物根结线虫基因组学研究进展

根结线虫是世界农业生产中危害最大的植物病原之一,目前仍缺乏安全有效的防治措施。深入揭示寄生线虫与植物之间互作的分子机制,利用生物技术进行抗性育种被认为是最有前景的抗线虫策略。在根结线虫基因组学研究方面,目前已经构建了北方根结线虫AFLP遗传连锁图谱,南方根结线虫和北方根结线虫基因组测序也已完成;基因组的注释和比较基因组学分析,较全面地描述了根结线虫的遗传组成;以差异表达分析和比较基因组学为主的方法鉴定了大量的重要基因;以RNA干扰、植物转化和蛋白互作为主的根结线虫基因功能研究也取得了一些进展。本文就根结线虫基因组学研究予以综述,并进一步探讨其研究方向和可持续抗线虫新策略的发展前景。     

输华马铃薯上哥伦比亚根结线虫风险分析

依据国际植物检疫措施标准(ISPM)规定的有害生物风险分析程序(PRAS),利用多指标综合评估方法,通过对哥伦比亚根结线虫(Meloidogyne chitwoodi)的生物学特性、地理分布、寄主、经济意义和危害性等方面进行分析,结合我国进口马铃薯种薯和马铃薯种植情况,确定了其在中国具有传入、定殖和扩散的可能性,对各指标值进行赋值运算,获得总指标值R为2.25,符合高风险的检疫性有害生物标准,因此建议将其列入输华马铃薯检疫性有害生物名单,实施风险管理。本文提出了风险管理措施方案。     

Systemic nematicidal activity of fluensulfone against the root-knot nematode Meloidogyne incognita on pepper

BACKGROUND: Fluensulfone, a new nematicide of the fluoroalkenyl group, has proved to be very effective in controlling root‐knot nematodes, Meloidogyne spp., by soil application. The systemic activity of this compound against M. incognita on peppers via soil drenching and foliar spray was evaluated. RESULTS: Root application of fluensulfone via soil drenching showed slight and no nematode control activity when applied 4 and 10 days, respectively, after inoculation. A single foliar spray of peppers with a fluensulfone solution at 3.0 g L^?1 prior to inoculation reduced the galling index by 80% and the number of nematode eggs by 73–82% of controls. The reduction in these parameters by fluensulfone was much higher than that obtained with oxamyl or fenamiphos at the same concentration. This activity was also observed when the plants were sprayed 21 days before inoculation. A series of experiments suggested that foliar spray with fluensulfone prior to inoculation reduces nematode invasion. However, foliar spray after inoculation did not inhibit nematode development inside roots. CONCLUSION: Fluensulfone showed relatively high nematode control activity when sprayed on the foliage before inoculation. Fluensulfone may be used as a foliar application, in addition to soil application, for root‐knot nematode control. Copyright © 2011 Society of Chemical Industry     

香蕉品种对根结线虫病的抗性鉴定

在5个香蕉栽培品种对香蕉根结线虫抗病性测试中明确,威廉斯-F和北蕉表现中感,威廉斯-Y、粉蕉和 红蕉表现高度感病。     

Diagnostics of the peach root-knot nematode,Meloidogyne floridensis using multiplex real-time PCR

European Journal of Plant Pathology - The peach root-knot nematode, Meloidogyne floridensis is an emerging pest of peach and other crops that is currently known to occur only in California,...     

阿维菌素和硫线磷对南方根结线虫的毒力

利用阿维菌素和硫线磷处理南方根结线虫离体卵与幼虫,测试其对线虫卵和卵块孵化以及对2龄幼虫的致死作用、活动能力、侵入能力的影响。结果表明阿维菌素和硫线磷均对线虫卵和卵块的孵化表现很强的抑制作用,阿维菌素5 μg/mL处理24 h对卵孵化抑制率高达82.57%,而硫线磷40 μg/mL处理24 h对卵孵化抑制率为73.05%;阿维菌素和硫线磷处理48 h对2龄幼虫的LD50分别为7.346 1、13.345 6 μg/mL;在阿维菌素2 μg/mL和硫线磷3 μg/mL处理中,2龄幼虫在沙柱中的平均移动距离仅为0.04 cm和0.05 cm,而对照处理的线虫平均移动距离为1.04 cm;在阿维菌素2 μg/mL和硫线磷50 μg/mL处理2龄幼虫48 h后,对番茄根部的侵入率为0.12%和0.45%,而空白对照处理线虫的侵入率达21.85%。     

植物有机质处理土壤防治黄瓜根结线虫病

用12种植物有机质处理土壤,在盆栽和田间小区试验条件下研究了它们对黄瓜根结线虫病的防治效果及其对黄瓜植株生长的影响。盆栽试验结果表明:蓖麻叶、麦糠、楝叶和花生饼粕对黄瓜根结线虫病防治效果较好,分别达到70.44％、68.17％、56.09％、54.92％;田间小区的试验结果与盆栽试验结果基本一致,防效较好的有麦糠、楝叶、蓖麻叶和菜籽饼粕4个处理,防效分别达到71.55％、69.99％、63.14％和62.19％。通过分析应用不同植物有机质处理地土壤对黄瓜植株的地上部鲜重、地下部鲜重以及株高的影响,发现麦糠、楝叶、松树锯末和菜籽饼粕对黄瓜的生长表现出明显的促生作用,其中麦糠的促生作用更为明显。     

Protective effect of Dryopteris crassirhizoma extracts in the control of the root-knot nematode Meloidogyne incognita

Journal of Plant Diseases and Protection - Root-knot nematodes (Meloidogyne spp.) are among the most damaging soilborne plant parasites and are responsible for large economic losses in a wide...     

根结线虫在中国的新纪录种——西班牙根结线虫(Meloidogyne hispanica Hirschmann)

 A root-knot nematode, Meloidogyne hispanica Hirschmann, was first described and illustrated from roots of papaya in Danzhou, Hainan province in China. The perineal pattern of female was characterized by oval shaped to rectangular with a low dorsal arch; dorsal striae varied from fine and wavy to coarse; lateral lines forked with fringe-like striae between lines and phasmidial ducts distinctly appeared. Male had high and rounded head region with labial disc and medial lips fused to form elongate lip structures. Second-stage juve-nile had distinct body annules and stylet with rounded, posteriorly sloping knobs, and the tail terminus was slender with indistinct hyaline. This Chinese new record of M. hispanica had a unique esterase phenotype (S2-M1) which was different from that of other Meloidogyne species.     

Quantification of tomato expansins in nematode feeding sites of cyst and root-knot nematodes

Journal of Plant Diseases and Protection - Sedentary endoparasitic nematodes induce specific feeding structures in roots of their host plants. The cyst nematode Globodera rostochiensis induces...