象耳豆根结线虫的PCR鉴定和检测方法

 象耳豆根结线虫是一种在中国具有潜在经济重要性的农作物病原物。为提供有助于控制象耳豆根结线虫传播扩散的方法,研制了该线虫的快速PCR鉴定和检测法。该方法PCR引物的扩增目标为rDNA-IGS2区域,其设计依据象耳豆根结线虫与南方、爪哇、花生和北方根结线虫在该区域核酸序列的差异。通过对6种近似根结线虫的不同地理群体及自然土壤线虫群体的测试,验证了设计的PCR引物针对象耳豆根结线虫的特异性和可靠性。本方法具有快速灵敏的特点,可用于象耳豆根结线虫单条线虫的直接鉴定以及混合土壤线虫群体中象耳豆根结线虫的检测。     

低钾逆境下根结线虫感染所诱导的番茄根巨型细胞的组织病理学反应

 Comparison of histopathological response and quantitative measurement of giant cell(GC) induced by Meloidogyne javanica in tomato root were studied under potassium-deficient(0.2 mmol/L K⁺) and replete conditions(control,6.0 mmol/L K⁺).K⁺-deficient stress did not impede the formation and maintenance of GC.The mean number of GC per feeding site as well as the mean diameter of GC did not differ between the treatments.However,the thickness of cell wall including components resulted from the accumulated polysaccharide and the length of cell-wall ingrowth increased 5-25 d after inoculation in K⁺-deficient as compared with K⁺-replete conditions.An increase of cell-wall ingrowth suggested a kind of compensational response to the potassium stress.     

功能型复合微生物菌剂防治黄瓜根结线虫的研究

根结线虫是一类重要的土传性病原物,对露地和温室蔬菜造成严重的经济损失。本研究通过平板亲和性试验,构建出一组(淡紫拟青霉、红灰链霉菌和苍白杆菌各1株)生物兼容性好、作用方式互补的功能型复合微生物菌群;以各功能菌株发酵菌体为活性成分,研制出一种防治黄瓜根结线虫的功能型复合微生物菌剂;对该复合菌剂对黄瓜根结线虫的防效及植株生物量和产量的影响进行了评价,大田试验结果表明,施用该复合菌剂的土壤线虫扩繁指数最低;移栽后38和105 d,该复合菌剂处理的根结级数分别为2.0和4.6,对病害防效为56.5%和42.5%,效果优于10%噻唑膦处理;施用该复合菌剂可以促进植株生长、增加黄瓜产量。本研究为蔬菜根结线虫病的生物防治提供了新思路。     

植物源提取物防治根结线虫的分子研究

针对内生真菌的生物防治,重点阐述了中草药提取物的杀虫活性、植物抗线虫基因的发现以及植物防御系统激发的最新研究.植物源提取物作为潜在的线虫杀虫剂,为生物源农药开发和利用提供新的思路.同时,对于今后线虫杀虫剂开发中存在的问题及解决方案进行了探讨,就其发展方向提出了建议.     

Resistance to Root-knot Nematodes (Meloidogyne spp.) in Vegetable Crops

Abstract

The development of root-knot nematode resistant vegetable varieties has provided an alternative control method to chemical and crop rotation. The term resistance is discussed. Work on 18 vegetables is reviewed.

Thirty tomato strains resistant to one or more Meloidogyne sp. are listed, there was a marked absence of reports on varieties resistant to M. hapla. Several workers have observed resistance in some cultivated and wild Solanum spp. The resistance could be increased by further sib and backcrossing experiments. Eggplant varieties tested for resistance to Meloidogyne spp. showed varying degrees of resistance in about 14 varieties. Further backcrossing studies between Solanum melongena and S. sysimbrifolium could provide useful results. Tests on resistance to nematodes in pepper have revealed many resistant varieties. All the pepper varieties tested were susceptible to M. hapla. The nature of resistance in sweet potato has been studied. Some varieties of Cucumis spp. have been found to be resistant to Meloidogyne spp. Since no resistance was found in C. melo, these wild species could be used in the development of a commercial muskmelon variety. Tests with 83 watermelon varieties indicated that all varieties were resistant to M. hapla. It was difficult to find resistance to Meloidogyne spp. in Cucurbita, but tests on wild species have yet to be carried out. Work on lima bean, snap bean, pea, soyabean, cowpea and broadbean has produced a limited number of resistant vegetable varieties, which are described. Since resistance patterns in plants may change under different environmental or biological conditions, it is essential to test varieties under these conditions for a long period before they are released for commercial cultivation. The advantages of using resistant vegetable varieties, as compared with other methods of pest control, are outlined.     

Interactions Between Meloidogyne artiellia, the Cereal and Legume Root-Knot Nematode, and Fusarium oxysporum f. sp. ciceris Race 5 in Chickpea

ABSTRACT In the Mediterranean Basin, Fusarium oxysporum f. sp. ciceris and the root-knot nematode Meloidogyne artiellia coinfect chickpea. The influence of root infection (after inoculation with 20 nematode eggs and second-stage juveniles per gram of soil) by two M. artiellia populations, from Italy and Syria, on the reaction of chickpea lines and cultivars with partial resistance to Fusarium wilt (CA 252.10.1.OM, CA 255.2.5.0, CPS 1, and PV 61) and with complete resistance to F. oxysporum f. sp. ciceris race 5 (CA 334.20.4, CA 336.14.3.0, ICC 14216 K, and UC 27) was investigated under controlled conditions. In genotypes with partial resistance, infection by M. artiellia significantly increased the severity of Fusarium wilt, irrespective of the fungal inoculum density (3,000 or 30,000 chlamydospores per gram of soil), except in cultivar CPS 1 at the lower fungal inoculum density. In genotypes with complete resistance to Fusarium wilt, infection by M. artiellia overcame the resistance to F. oxysporum f. sp. ciceris race 5 in CA 334.20.4 and CA 336.14.3.0 but not in ICC 14216 K, irrespective of the fungal inoculum density, and overcame the resistance in UC 27 only at the higher inoculum density. Infection by the nematode significantly increased the number of propagules of F. oxysporum f. sp. ciceris race 5 in root tissues of genotypes with complete resistance to Fusarium wilt, compared with roots that were not inoculated with the nematode, irrespective of the fungal inoculum density, except in ICC 14216 K, in which this effect occurred only at the higher inoculum density. Reproduction of an M. artiellia population from Syria in the absence of F. oxysporum f. sp. ciceris race 5 was significantly higher than that of a population from Italy in all tested chick-pea genotypes except ICC 14216 K. However, there was no significant difference between the reproduction rates of the two nematode populations in plants infected with F. oxysporum f. sp. ciceris race 5, irrespective of the fungal inoculum density and the reaction of the genotypes to the fungus.     

Cereal Cyst Nematode, Soil Heating and Fungal Parasitism1

Experiments on winter heating of cereal cyst nematode-infested soil have been carried out during 4 years on light loam in eight concrete pipes (l-m diam.) dug into the soil. The soil in four of the pipes was heated to a temperature of 5oC during the winter periods. Temperature was measured at a depth of 5 cm. The heating was carried out by means of buried electrical cables. Soil temperature in the remaining pipes followed the natural fluctuation. The host plant was Sun II oats. Statistical analysis of the results for all the years together showed that the propagation of nematode populations was significantly lower in heated than in non-heated plots. Investigation of soil samples in spring and autumn 1980 for eggs and larvae, as well as fungal parasitism of these, showed that numbers of eggs and larvae were significantly lower in heated than in non-heated plots and the percentage of parasitized eggs and larvae was significantly higher in heated than in non-heated plots. Verticillium chlamydosporium seems to be a main parasitic fungus.     

RAPD Characterization of Single Females of the Root-knot Nematodes, Meloidogyne Spp.

Random amplified polymorphic DNA fingerprinting was performed on single females of root-knot nematodes, Meloidogyne spp., using a new procedure for DNA isolation. One-fourth of the total DNA amount isolated from a single female proved to be sufficient as a template in a polymerase chain reaction. Electrophoretic patterns of the amplified fragments were reproducible between replicates from a single female or sister females from the same progeny, and identical to those obtained with genomic DNA purified from a large number of nematodes. Moreover, a comparative analysis over three successive generations showed stability of the amplification patterns, thus demonstrating the utility of this procedure for epidemiological and ecological studies on root-knot nematodes.     

Chemical Root-Dips for Control of Root-knot Nematode Attacking Tomato

Abstract

Dimethoate 0.5% for 6 h was the most effective dip for suppressing the root-knot nematode, Meloidogyne incognita (Kofoid and White, 1919) (Chitwood, 1949). It was better than all the other treatments except 0.025% dimethoate for 6 h. Dimethoate at 0.1 and 0.2% and 0.2% parathion and diazinon as 6 h root-dips were phytotoxic. Diazinon controlled the nematode poorly and malathion was ineffective.     

Experience in Denmark with Cereal Cultivars Resistant to Cereal Cyst Nematode (Heterodera avenae Woll.)1)

On the basis of investigations on the cereal cyst nematode's distribution, it is presumed that one third of all the cereal growing areas in Denmark is infested to a degree, and that yield losses of 5 % or more may be assumed. This means an annual loss of about 100 million D.Kr. By using resistant cultivars every second year, the population of Heterodera avenae Woll. can be kept at a harmless level. It may be assumed that intensive growing of nematode-resistant cereals includes a risk of promoting the occurrence of pathotypes other than the 2 known to exist in Denmark. So far, there is no indication for their existence.     

PGPR对番茄南方根结线虫病的影响

于温室盆栽条件下初步研究了4种根围促生细菌（PGPR）对番茄植株生长和南方根结线虫Meloidogyne incognit病发生情况的影响。结果表明接种多粘芽孢杆菌Bacillus polymyxa或芽孢杆菌菌株B697的番茄植株高度、地上部和地下部干重均显著大于对照,而巨大芽孢杆菌B. megaterium和固氮螺菌Azospirillum sp.菌株A135无促生作用。接种多粘芽孢杆菌＋南方根结线虫和B697菌株＋南方根结线虫两处理的二龄幼虫数、雌虫数、线虫总数、根上卵囊数、卵囊含卵量、发病率和病情指数显著低于只接种南方根结线虫的对照。多粘芽孢杆菌、B697菌株、巨大芽孢杆菌和A135菌株对南方根结线虫的防效分别达65.4%、68.2%、53.8%和53.8%。     

Bioefficacy of Trichoderma Species Against Javanese Root-Knot Nematode,Meloidogyne javanica,in Green Gram

Root-knot nematodes are mainly controlled by using synthetic nematicides, but their excessive use is prohibited due to associated health hazards which demand for suitable alternatives. The overreliance on nematicides can be curtailed by using biological control agents possessing nematicidal or nematostatic properties. Therefore, in the present study, effectiveness of seven indigenous species of Trichoderma were tested for their ability to suppress the population of Javanese root-knot nematode, Meloidogyne javanica, and improve growth variables of green gram. All the Trichoderma species resulted in an increase in shoot and root lengths and shoot weight while a decrease was observed in root weight. Maximum increase in shoot length (45.5%) was found in case of T. harzianum followed by T. hamatum and T. viride whereas the increase was the minimum where T. pseudokoningii and T. koningii were applied. Similarly, maximum increase in shoot weight was recorded with T. viride (56.1%) followed by T. harzianum (55%) and the minimum with T. pseudokoningii. As regards root length, it was the maximum in treatments with T. hamatum (46.2%) and T. harzianum (45.1%) and minimum with those where T. koningii and T. pseudokoningii were applied. Contrarily, maximum reduction in root weight was observed in treatments where T. harzianum (37.8%) and T. viride (35.8%) were applied while T. koningii and T. pseudokoningii resulted in minimum decrease. All the Trichoderma species significantly caused reductions in the number of galls and eggs and reproductive factor of the nematode over control. Maximum reduction in numbers of galls and eggs were observed with T. viride (49 and 53%) followed by T. harzianum (46 and 53%) while the minimum reduction was recorded with T. pseudokoningii followed by T. atroviride. Likewise, T. viride caused the maximum reduction in reproductive factor of M. javanica (81%) followed by T. harzianum (78%) and T. asperellum (75%). On the other hand, the minimum reductions in reproductive factor were observed with T. pseudokoningii and T. koningii.

     

三尖杉对花生根结线虫发育的影响

 采用室内培养和盆栽试验的方法,研究了三尖杉(Cephalotaxus fortunei)枝叶提取物及三尖杉枝叶粉末,对花生根结线虫(Meloidogyne arenaria)发育的影响。结果表明,三尖杉枝叶提取物对花生根结线虫胚胎发育及二龄幼虫孵化有明显抑制作用。三尖杉枝叶粉末处理对花生根结线虫胚后发育的影响,主要表现在推迟二龄幼虫及成虫的发育,而对三龄及四龄幼虫的发育无明显影响。三尖杉枝叶粉末处理可显著降低雌虫的产卵量。     

Estimation of Root-knot Nematode Infestation Levels on Roots Using a Rating Chart

Abstract

A rating chart is given which enables easy and accurate field assessment of damage by root-knot nematodes (Meloidogyne spp.) on many crops, based on the percentage and types of roots galled. It should be of use both to nematologists and untrained field workers.     

蚯蚓粪及浸提液对番茄根结线虫的防治效果

通过室内生测和盆栽试验,研究了蚯蚓粪及其浸提液对南方根结线虫的防治作用。结果表明,蚯蚓粪浸提液对南方根结线虫卵囊和卵的孵化表现出明显抑制作用,当浸提液浓度为90%,卵囊孵化的相对抑制率为71.63%,离体卵的孵化率仅为11.88%。对2龄幼虫具有明显的击倒和致死作用,当浸提液浓度为90%,2龄幼虫的死亡率达88.46%。盆栽试验表明,栽培基质混入蚯蚓粪对番茄根结线虫病起到一定的控制作用,当蚯蚓粪占栽培基质的比例为75%时,对根结线虫病的防治效果可达70%以上,但对番茄的生长产生了不良影响,株高仅为47.33 cm,地上部鲜重仅为84.15 g;而当蚯蚓粪比例为25%时,番茄的生长情况最好,株高为61.33 cm,地上部鲜重为241.65 g,对根结线虫病的防治效果达到36.3%。     

Biological Control of the Root-Knot Nematode Meloidogyne javanica by Trichoderma harzianum

ABSTRACT The fungal biocontrol agent, Trichoderma harzianum, was evaluated for its potential to control the root-knot nematode Meloidogyne javanica. In greenhouse experiments, root galling was reduced and top fresh weight increased in nematode-infected tomatoes following soil pretreatment with Trichoderma peat-bran preparations. The use of a proteinase Prb1-transformed line (P-2) that contains multiple copies of this gene improved biocontrol activity in the greenhouse experiments compared with the nontransformed wild-type strain (WT). All the Trichoderma strains showed the ability to colonize M. javanica-separated eggs and second-stage juveniles (J2) in sterile in vitro assays, whereas P-2 also penetrated the egg masses. This protease-transformed line presented the same nematicidal and overall proteolytic activity as the WT in in vitro tests in which concentrated soil extracts from Trichoderma-treated soils immobilized the infective J2. However, the J2 immobilization and proteolytic activities of both P-2 and the WT were higher than those obtained with strain T-203. Characterization of the activity of all Trichoderma strains soil extracts on J2 showed that it was heat resistant and restricted to the low-molecular-weight fraction (less than 3 kDa). It is suggested that improved proteolytic activity of the antagonist may be important for the biological control of the nematodes.     

穿刺巴氏杆菌防治植物根结线虫病的研究现状及其应用前景

本文简要介绍了有关穿刺巴氏杆菌研究的历史,介绍并讨论了利用穿刺巴氏杆菌防治植物根结线虫病的研究进展及应用前景。     

假格里尼翁苍白杆菌A-29对南方根结线虫的防治效果及其鉴定

南方根结线虫是一种重要的植物寄生线虫,严重发生时可造成巨大的经济损失。本研究测定了菌株A-29发酵液对南方根结线虫的致死效果和盆栽防效,并对其进行了种类鉴定。结果表明,菌株A-29发酵滤液原液、5倍液和10倍液处理南方根结线虫后,2龄幼虫的致死率在24 h和48 h后达71.09%～95.45%,卵的孵化抑制率4 d时为59.25%～87.86%,其死亡率随处理浓度的提高而增加;菌株A-29发酵液处理60 d后对番茄根结线虫的防治效果达75.00%,番茄植株鲜重、根系干重和植株高度分别增加38.41%、33.52%和20.01%;根据菌株A-29的形态特征、生理生化特征、16S rRNA基因序列及其系统发育关系,将其鉴定为假格里尼翁苍白杆菌Ochrobactrumpseudogrignonense。研究表明,菌株A-29不仅对南方根结线虫具有良好的致死效果,而且对番茄植株具有明显的促生作用,是一株具有应用前景的生防菌。