杀线虫植物以及植物源杀线虫活性化合物研究与应用进展

植物寄生线虫现已成为危害农业生产的第二大类病害,其防治迫在眉睫。线虫的生物防治是一种新型的线虫防治策略,主要是利用动植物和微生物及其次级代谢产物对线虫进行防治。植物源次级代谢产物即植物源化合物,源于自然,是植物源农药的核心。相比于化学杀线虫剂,植物源杀线虫剂对环境影响较小、靶向性强且不易使线虫产生抗药性。因此,从植物中获得结构新颖且杀线虫活性好的小分子化合物并将其开发成绿色农药,对于线虫病的防治具有重要意义。本文对杀线虫植物、具有杀线虫活性的植物源化合物及其杀虫机理、植物源杀线虫农药的应用情况展开综述,并对该研究领域进行了展望,希望能为植物寄生线虫病的防治与植物源杀线虫农药的开发利用提供参考和帮助。     

苏云金芽胞杆菌杀线虫活性因子分析及杀虫机制研究进展

苏云金芽胞杆菌Bacillus thuringiensis(Bt),是一种重要的昆虫病原细菌,对多种农业害虫包括鳞翅目、鞘翅目、双翅目、膜翅目和线虫等具有高特异杀虫活性,是迄今应用最广泛的微生物杀虫剂。本文总结了杀线虫Bt菌株的活性因子种类以及不同类的活性物质杀线虫机制的分析,能够为生物杀线剂的研究与创制提供理论基础。     

苏云金芽胞杆菌防治植物寄生线虫的研究进展

植物寄生线虫是一类重要的植物病原生物,给农业生产造成巨大的损失.传统方法防治植物寄生线虫都存在一定的局限性.研究发现苏云金芽胞杆菌对线虫有毒杀活性,为防治植物寄生线虫寻找到了一条新途径.文章介绍了苏云金芽胞杆菌防治植物寄生线虫的研究现状,着重阐述了苏云金芽胞杆菌的杀线虫晶体蛋白及其基因、杀线虫机制等方面的研究进展,并探讨了其中存在的问题及其对策.     

杀线虫剂产品研究进展

植物寄生线虫是植物的一类重要病原物,全世界每年因线虫造成的损失大约1500亿美元.本文就目前全球杀线剂的市场需求、国外杀线剂农药登记情况、我国杀线剂农药登记情况与生产企业分布情况及杀线剂开发过程中存在的主要问题等方面展开分析,能够为杀线剂产品的研究提供理论基础.     

三种杀线虫剂对盆景上线虫防治效果比较

本研究系统地比较了克线丹、阿维菌素和克线磷等3种杀线虫剂对盆景上线虫的防治效果.施用10%克线丹乳油和1.8%阿维菌素乳油2000倍、1000倍和500倍液7天,30天和60天后,罗汉松、黄杨、紫竹等盆景中线虫均有不同程度的减退率,综合评价以500倍处理的减退率最大.由于该两种杀线虫剂为乳油采用浸盆景处理,可保证整个盆景内的所有根系及土壤均接触到杀线虫剂,从而有效地杀灭其中的植物外寄生线虫和腐生线虫,这方面要优于对照药剂10%克线磷颗粒剂在盆景根围的使用.     

南方根结线虫生物防治研究进展

本文对南方根结线虫生防因子食线虫真菌、细菌、放线菌、杀线植物的种类,及其生防因子对线虫的作用方式等进行概述。     

新生物杀线虫剂对线虫致死力室内测定

室内测定了新研制的3种生物杀线虫剂及其复配剂对根结线虫(Meloidogyen spp.)和松材线虫(Bursaphelenchusxy Lophilus)致死力,在25℃恒温、60%RH恒湿条件下4种杀线虫剂,杀线剂1、杀线剂2、杀线剂3对两种线虫的致死力都较强,药后72h根结线虫死亡率达98%,松材线虫死亡率达80%。杀线剂复配效果好于单一效果。     

对植物寄生线虫具有活性的苏云金芽胞杆菌研究进展

植物寄生线虫是重要的植物病原物之一,给农业生产带来了巨大的经济损失。长期以来,一直缺乏有效防治植物寄生线虫的手段。苏云金芽胞杆菌（Bacillus thuringiensis,Bt）是重要的昆虫病原细菌,广泛应用于鳞翅目、双翅目、鞘翅目害虫等农林及卫生害虫的防治;部分Bt菌株对植物寄生线虫具有很高的活性。本文总结了杀植物寄生线虫Bt菌株筛选的模型与方法的建立、Bt菌株杀植物寄生线虫的作用机理及其相关应用、以及杀植物寄生线虫的伴胞晶体蛋白与相关基因等,可望为杀植物寄生线虫Bt制剂的研究与开发提供借鉴。     

杀线虫植物内生细菌和根际放线菌对根结线虫的防效

为了获得防治植物寄生线虫的微生物菌种资源和防效稳定的生防菌剂,以松材线虫为靶标,采用直接触杀法对植物根际放线菌和内生细菌进行了筛选,通过盆栽试验测定了筛选到的菌株发酵液对根结线虫的防治效果,并将有初步防效的菌株制成固体菌剂,分别测定单菌剂和复合菌剂的防效。共筛选到16株放线菌和4株内生细菌具有杀线虫活性,其中2株放线菌和3株内生细菌的发酵液对根结线虫防效明显;放线菌和内生细菌混合发酵液均保持了对根结线虫的抑制作用,但是放线菌和细菌菌株的固体菌剂混合后对根结线虫的防效低于细菌单菌株的防效。植物内生细菌BCM2和CCM7单菌株的固体菌剂对番茄根结线虫的防效最高,分别达到了83.31%和83.07%。表明高杀线虫活性的植物内生细菌制备的固体菌剂具有应用潜力。     

3种杀线虫剂对香蕉土壤线虫群落结构的影响

比较不同杀线虫剂对植物寄生线虫的杀灭效果及其对土壤线虫群落的影响,对于杀线虫剂的选择具有指导意义。本研究比较了5亿活孢子/g淡紫拟青霉粉剂、1.8%阿维菌素乳油和10%噻唑膦颗粒剂3种杀线剂对植食性线虫的防治效果及其对土壤线虫群落结构的影响。结果表明:植物寄生线虫是连作蕉园优势营养类群。苗期时只有阿维菌素表现出对植食性线虫的杀灭效果;蕾期3种杀线虫剂均表现出显著的杀灭效果,植食性线虫的数量较CK分别减少49.3%、17.4%和84.2%;苗期时1.8%阿维菌素乳油表现出对螺旋线虫属和肾形线虫属的杀灭效果,10%噻唑膦颗粒剂处理中肾形属丰度较CK减少了20.3%;蕾期相比于CK,5亿活孢子/g淡紫拟青霉粉剂、1.8%阿维菌素乳油和10%噻唑膦颗粒剂处理中植物寄生线虫类群数均有所降低,各处理对优势属螺旋线虫属和肾形线虫属均有杀灭作用,减少的比例分别为48.2%、40.6%、95.7%和50.1%、7.1%、84.5%,差异显著。3种杀线剂处理均降低了土壤中的自由生活线虫种类和丰度。苗期1.8%阿维菌素乳油处理能显著增加食细菌线虫的数量,5亿活孢子/g淡紫拟青霉粉剂和10%噻唑膦颗粒剂处理的自由生活线虫成熟指数MI和多样性指数H′较CK显著降低;香蕉蕾期处理间MI没有显著差异,10%噻唑膦颗粒剂处理的植物寄生线虫成熟指数PPI较CK显著减少,均匀度指数J′显著高于其他处理。综上所述,10%噻唑膦颗粒剂的效果最好,持效期长,对植食性线虫有明显的杀灭效果,对土壤线虫类群多样性和线虫成熟指数无显著影响,适宜在香蕉种植园推广使用。     

植物寄生线虫生物防治中存在的问题及解决途径

根据国内外研究现状,针对在植物寄生线虫生物防治中存在的问题,提出了可行的解决办法———获得具有抗药性的线虫生防菌;同时,阐述了选择所兼容化学药剂的原则,客观地分析了线虫抗药性生防菌的意义及问题,并如何对其进一步研究、开发和利用进行了展望。     

Verkapselung von bakteriellen Antagonisten und eines nematophagen Pilzes

Data and results are presented from a project on the development and application of hydrogel capsules for the delivery of two biological control agents, namely bacterial antagonists to control phytopathogenic fungi and a nematophagous fungus to control plant-parasitic nematodes. The focus is on encapsulation on lab and technical scales, drying and storage of the formulations, application to the greenhouse and field, and technology transfer to a biocontrol company.     

Compounds inhibitory to nematophagous fungi produced by Bacillus sp. strain H6 isolated from fungistatic soil

Soil fungistasis can cause inconsistent control by nematophagous fungi of plant-pathogenic nematodes in field situations. Recent studies have shown that production of fungistatic compounds by bacteria was the principal explanation for soil fungistasis. The culture filtrate of Bacillus sp. strain H6, a strain representative of the dominant colony types isolated from fungistatic soils, showed strong inhibitory activity against nematophagous fungi by inducing unusual swelling in the conidia and the germ tubes of nematophagous fungi, thereby preventing the fungi from proliferating. This inhibitory mechanism is novel in comparison with other known mechanisms. Antifungal activity of the culture filtrate of strain H6 was maximal after culture in Luria Bertani (LB) broth (pH 7.0) at 36°C for 36 h. The inhibitory effect of the compounds produced by Bacillus sp. strain H6 was not significantly influenced by pH, and the inhibitory compounds in the culture filtrate were thermostable. After being partially purified by thin layer chromatography (TLC) on silica gel plates, characterization by colour reactions and positive fast atom bombardment mass spectrometry indicated that the inhibitory compounds showed similarity to iturin A group compounds.     

Nematophagous Verticillium spp. in soils infested with Meloidogyne spp. in Cuba: Isolation and screening

Root-knot nematodes cause substantial economic loss of yield in coffee plantations and vegetable crops in Cuba. At present, methods to control the nematodes are ineffective or inappropriate and alternatives are being sought. The nematophagous fungus Verticillium chlamydosporium (Goddard) was isolated from soils collected from coffee plantations and infected root-knot nematode eggs from roots of tomato plants grown in these soils. A total of 83 isolates were collected and identified morphologically as V. chlamydosporium var. chlamydosporium, V. chlamydosporium var. catenulatum, V. psalliotae, V. suchlasporium and an isolate of V. chlamydosporium var. chlamydosporium with unusually large dictyochlamydospores. From these, 24 that represented a range of origins were selected and screened for their ability to parasitize eggs of root-knot nematodes, colonize the rhizosphere of barley roots and produce chlamydospores. None of the isolates grew at temperatures below 15°C and V. suchlasporium grew at a faster rate at lower temperatures than the other isolates. These were also screened in the glasshouse and V. chlamydosporium var. catenulatum caused the greatest reduction in nematode populations. One isolate of each subspecies of V. chlamydosporium was tested with the standard, Rothamsted isolate 10, on a range of host plants. The greatest reduction in numbers of nematodes occurred on tomato plants (cv. Pixie). The Rothamsted isolate 10 reduced numbers of nematodes toa greater extent than the other isolates, and therefore has the greatest potential as a biological control agent of root-knot nematodes.     

粗皮侧耳生物学特性及其与杀线虫毒力的关系

 本文报道粗皮侧耳(Pleurotus ostreatus)的生物学特性,尤其是生物学特性与杀线虫毒力的关系。该菌的野生型、驯化型、单孢分离株及孢子分离株的菌丝均能迅速杀死线虫。在固体培养条件下,成熟菌丝产生丰富的毒素球,幼嫩菌丝不产生毒素球;该菌在多种固体培养基,甚至营养缺乏的水琼脂上也生长良好;生长的最适条件为24~28℃、pH5.6~8.0、固体或液体遮光培养。尽管营养、温度、pH及光照等对菌丝生长均有显著影响,但并不影响其对线虫的毒力,各菌株间毒力无差异,线虫与菌丝接触48h,死亡率均达90%以上;液体培养滤液能杀死线虫,但其对线虫毒力的强弱却与菌株、滤液浓度及培养时间等有关。首次以实验证明了该菌在液体培养条件下可产生杀线虫毒素。     

产生几丁质酶的交枝顶孢(Acremonium implicatum)对南方根结线虫生防潜力

 由于化学杀线剂给环境带来了污染问题,寄生线虫的生防真菌成为研究热点。为进一步鉴定和筛选高效食线虫真菌,从山东日照五莲烟草北方根结线虫卵中分离到1株较高应用潜力菌株WLE1。根据形态学和rDNA-ITS序列分析方法鉴定该菌为交枝顶孢Acremonium implicatum。该菌是1株能够产生几丁质酶的食线虫真菌,在第4天几丁质酶活性到达高峰,为18.49 μmol·h^-1·mL^-1 ,直到第16天依然维持较高活性;活性电泳测定其几丁质酶分子量分别为98.0、82.9、70.2和35.9 kDa;交枝顶孢几丁质粗酶液处理南方根结线虫卵,第7天卵的孵化抑制率为80.17%。该菌能够寄生南方根结线虫卵、2龄幼虫和雌虫。第6天卵和2龄幼虫的寄生率分别为82.11%和73.97%。说明具有高效产生几丁质酶特性且能寄生南方根结线虫不同生活史阶段的交枝顶孢WLE1对南方根结线虫具有巨大生防潜力。     

Effects of three microbial broth cultures and an organic amendment on growth and populations of free living and plant-parasitic nematodes on banana

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.     

棉隆与淡紫拟青霉联合防治番茄根结线虫病的效果评价

为明确土壤熏蒸与生防微生物对番茄根结线虫病的联合作用效果,采用移栽前棉隆熏蒸处理后穴施淡紫拟青霉Paecilomyces lilacinus YES-2-14生防菌剂的方法在温室大棚开展了联合防治试验。结果表明,棉隆用量为35 g/m~2时,24周拉秧时线虫数量减少90%以上,防效达到85.5%;移栽时穴施浓度10~7~10~8CFU/g的淡紫拟青霉菌剂,24周拉秧时防效为44.4%~59.6%;而当线虫初始密度达到674头/100 g土时,单一菌剂防效只有12.5%,但番茄长势和产量显著提高。棉隆熏蒸后再联合施用淡紫拟青霉菌剂,2个月和5个月时防效比单一棉隆处理分别提高14.1%和21.8%,比单一菌剂处理提高14.3倍和4.1倍,产量较对照、棉隆熏蒸和单一菌剂处理分别提高22.1%、9.5%和2.4%,且该处理地块线虫数量始终最低,与对照差异显著,而淡紫拟青霉数量则高于单一淡紫拟青霉菌剂处理。表明棉隆和淡紫拟青霉菌剂联合使用不仅能显著降低线虫数量,有效防治番茄根结线虫病,还能够促进植株生长并提高产量。     

食线虫真菌蠕虫埃斯特菌对植物寄生线虫的侵染特性

为评价食线虫真菌蠕虫埃斯特菌Esteya vermicola菌株NKF 13222的生防应用价值,采用2%水琼脂培养基平板接种法测定了该菌株对7种植物寄生线虫的诱引、黏附和侵染能力,并比较了其对不同线虫的侵染特性.结果显示,该菌株的菌丝对松材线虫、拟松材线虫、腐烂茎线虫和水稻干尖线虫均有诱引作用,而对南方根结线虫、禾谷孢囊线虫和穿刺短体线虫无诱引作用;菌株的粘性分生孢子对有诱引现象的4种线虫都能黏附,接种24 h后的黏附率达到82%～99%,对无诱引现象的3种线虫不能黏附;粘性分生孢子黏附虫体后对不同线虫的侵染力存在差异,接种7 d后的松材线虫死亡率可达98%,而拟松材线虫、腐烂茎线虫和水稻干尖线虫死亡率分别为43%、35%和9%.表明蠕虫埃斯特菌不仅是松材线虫的强内寄生真菌,而且对其它重要植物寄生线虫也具有一定的应用潜力.