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1.
昆虫病原线虫与体内细菌共生,专性寄生在昆虫体内,在害虫生物防治中发挥着重要作用。昆虫病原线虫致病性研究是其高效应用的基础,涉及线虫及其共生细菌对昆虫的交互作用。本文针对斯氏属和异小杆属线虫的致病因子及这类线虫与寄主昆虫互作机制进行了综述,为昆虫病原线虫的致病机制研究和应用提供参考。  相似文献   

2.
致病杆菌和发光杆菌抗菌代谢产物研究进展   总被引:1,自引:0,他引:1  
致病杆菌Xenorhabdus和发光杆菌Photorhabdus是昆虫病原线虫肠道共生细菌,具有对宿主昆虫致病和对寄主线虫共生的双重特性,是一类特殊的生防细菌资源,其代谢产物具有广泛的杀虫和抑菌功能。本文综述了近年来昆虫病原线虫共生细菌产生的抗菌物质、编码抗菌代谢产物的基因及抗菌机制的研究进展。  相似文献   

3.
格氏线虫表皮蛋白和分泌蛋白都具有抑制昆虫免疫反应的能力,能够帮助侵染期线虫侵染寄主,但两者所含蛋白组分并不相同,从而导致蛋白活性也有所差异。本研究采用乙醇萃取和昆虫匀浆诱导,分别从侵染期的格氏线虫体表及分泌物中得到了表皮蛋白和分泌蛋白,并比较了这两者之间的异同。结果表明,无论是在昆虫体内还是体外,侵染期线虫表皮蛋白和分泌蛋白都具有抑制昆虫免疫反应的生物活性,并且分泌蛋白的活性更强。本研究为进一步研究线虫侵染与昆虫免疫间的相互关系和线虫抑制昆虫免疫反应的作用机理提供了科学佐证。  相似文献   

4.
嗜线虫致病杆菌CB6菌株对棉铃虫的生物活性   总被引:1,自引:0,他引:1  
致病杆菌属(Xenorhabdus)及近缘的发光杆菌属(Photorhabdu)是昆虫病原线虫肠道共生菌。共生菌被线虫释放到寄主血腔中后,能导致昆虫迅速死亡,且产生抗菌成分防止虫尸腐烂[1]。由于从土壤或水源中未能分离到自由存活的共生细菌,因此早期认为这类细菌只有在与线虫共生状态下才对昆虫有致死作用[2]。1990年以来,Ensign等[3]和潘映红等[4]研究发现这类细菌的胞外蛋白和脂多糖注射到大蜡螟(Galleriamellonella)体内后均有杀虫活性。1998年,Science报道了发光杆菌(P.luminescens)菌株W 14分泌的高分子量复合体蛋白对烟草天蛾(Manducasexta…  相似文献   

5.
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。  相似文献   

6.
昆虫病原线虫共生细菌对植物病原菌的抑制作用   总被引:1,自引:0,他引:1       下载免费PDF全文
昆虫病原线虫共生细菌能够产生多种次生代谢产物,如抑菌物质、杀虫蛋白和胞外酶等。其中产生抗生素是共生细菌的普遍特征,并且其代谢产物对多种植物病原菌具有抑制作用,特别是对疫霉具有较好的拮抗作用。对共生细菌的有效抑菌成分进行分离提取,有助于发现新的抗生素。本文综述了昆虫病原线虫共生细菌对植物病原菌的抑制作用以及抑菌作用活性物质的种类、致病机理、产生条件等方面的研究进展。  相似文献   

7.
初生型发光杆菌属(Photorhabdus)及嗜线虫致病杆菌属(Xenorhabdus)细菌分别与异小杆线虫属(Heterorhabdltis)和斯氏线虫属(Steinernema)昆虫病原线虫互惠共生。这类昆虫病原细菌在稳定生长期分别产生两种形态各异的胞内晶体蛋白。本文回顾了这类蛋白的研究历史和最新的研究进展,特别是胞内晶体蛋白的理化性质和生物学功能,同时讨论这种晶体蛋白的研究方法与技术。  相似文献   

8.
为探究昆虫病原线虫对蛴螬的致病机理,测定了蛴螬感染嗜菌异小杆线虫沧州品系 Heterorhabditis bacteriophora Cangzhou strain后其酚氧化酶(PO)、羧酸酯酶(CarE)活性以及血淋巴蛋白、海藻糖含量的变化。结果表明,线虫侵染后蛴螬 PO 和 CarE 活性大致表现出“升高-峰值-下降”的变化过程,华北大黑鳃金龟 Holotrichia oblita Faldermann、暗黑鳃金龟 H. parallela Motschulsky 和铜绿丽金龟 Anomala corpulenta Motschulsky 3种金龟子2龄幼虫PO活性分别在24、12、36 h达到最大并显著高于对照,CarE活性则分别在48、36、48 h达到最大且显著高于对照。注射线虫悬浮液至铜绿丽金龟3龄幼虫血腔后20 h,血淋巴蛋白含量最高且显著高于对照,28 h含量最低且显著低于对照;海藻糖含量在注射后20 h达到最高但与对照差异不显著,28 h含量最低且显著低于对照。两种酶活性以及能源物质含量的变化,表明嗜菌异小杆线虫入侵对蛴螬免疫系统和代谢过程产生了一定影响,也为揭示昆虫病原线虫对蛴螬的致病机理提供了一定的试验数据。  相似文献   

9.
昆虫病原线虫的应用近况   总被引:11,自引:1,他引:11  
杨平 《昆虫天敌》1995,17(3):140-143
昆虫病原线虫(Entomopathogenic nematodes)是害虫的天敌,是害虫生物防治中的一个重要因子。它的研究应用从30年代发现距今已有50多年的历史,其中携带共生细菌的斯氏线虫属Steinernema Travassos和异小杆线虫属Heterorhabditis Poinar是在害虫生物防治中最有潜力的类群。各国科学家已发表了不少线虫的生物学、生态学、大量繁殖方法和防治效果的研究报告。利用昆虫病原线虫防治害虫有以下优点:①线虫的寄主范围广,可以利用线虫防治多种害虫;②可以人工培养基大量繁殖线虫;③线虫可以主动地寻找寄主,对土栖和隐蔽的钻蛀害虫效果高;④线虫体内带有共生细菌,具高的杀虫能力,能在16至48小时内杀死寄主昆虫;⑤线虫对环境安全,有一定的抵抗力,可与一些杀虫剂混用。本文拟就日前线虫的生产、应用,影响线虫效用的因素和线虫应用的前景浅淡。  相似文献   

10.
昆虫病原线虫对甘薯蚁象的致病力测定   总被引:2,自引:0,他引:2  
昆虫病原线虫是隐蔽性害虫的有效生物防治因子,对8种斯氏线虫和3种异小杆线虫进行筛选证实夜蛾斯氏线虫Steinernema feltiae对甘薯蚁象Cylas formicarius的致病力最强;在此基础上进一步研究了11个不同地理来源的S.feltiae品系对甘薯蚁象末龄幼虫的致病力,获得强致病力的品系S.feltiae JY-17并测定了不同因素对该线虫品系致病力的影响。研究结果表明:在25℃条件下,甘薯蚁象不同发育阶段对S.feltiae JY-17的敏感性依次为末龄幼虫〉低龄幼虫〉蛹〉预蛹期〉成虫;在不同测试温度条件下,sfeltiae JY-17致病力由高到低顺序为25℃〉20℃〉30℃〉15℃〉10℃〉35℃;在25℃条件下,当寄主密度为196.6头·m^-2时,线虫对蚁象末龄幼虫的LD50=5.532条·头^-1,LD90=28.049条·头^-1;当线虫与寄主比例为5:1时,LT50=44.306h。本研究为利用昆虫病原线虫防治甘薯蚁象提供了理论依据。  相似文献   

11.
12.
甘肃定西地区马铃薯线虫病病原的分离鉴定   总被引:3,自引:1,他引:2  
为明确甘肃省定西市马铃薯线虫病的病原种群分类地位,采用形态学结合分子生物学的方法对该地区马铃薯上的4个线虫群体进行了鉴定,观察和测量其形态特征值,基于r DNA-ITS序列以UPGMA法构建线虫群体的系统发育树,并按照柯赫氏法则进行了致病性测定。结果表明,4个线虫群体在形态学上与马铃薯腐烂茎线虫Ditylenchus destructor一致,但群体DX27与群体DX11、DX16、DX19雌虫的体长、体长/食道长、体长/尾长值存在极显著差异。利用通用引物TW81/AB28扩增r DNA-ITS序列均获得长度为915 bp的片段;序列比对分析表明,群体DX27与其它3个群体相比在ITS1区的第96~255 bp片段内有25个碱基的差异;系统发育树显示,群体DX27与C型群体聚为1支,群体DX11、DX16、DX19与B型群体聚为1支。根据形态学特征及r DNA-ITS序列分析结果确定该病原线虫为马铃薯腐烂茎线虫,其中群体DX27属于C型,群体DX11、DX16、DX19属于B型。  相似文献   

13.
Organic amendments and green manure are potential alternatives to the harmful chemical control means currently used against plant-parasitic nematodes. In this work, Chrysanthemum coronarium was applied to the soil as a green manure to control the root-knot nematodes Meloidogyne incognita and M. javanica. Chrysanthemum coronarium significantly reduced nematode infection of tomato roots and improved plant-top fresh weight, both in the greenhouse and in microplots. Other green manures, derived from Anthemis pseudocotula, wild chickpea (Cicer pinnatifidum), Geranium spp. and wheat, were not as effective as C. coronarium. Chrysanthemum coronarium, retained its nematicidal activity even when applied as a dried material. Only mature C. coronarium plants, in their flowering stage, exhibited nematode control activity, but the green plant parts were more effective than the flowers. An aqueous extract of C. coronarium exhibited in vitro, nematostatic activity towards M. incognita and M. javanica second-stage juveniles and inhibited their hatching from eggs and egg-masses; its nematostatic activity was expressed also against other phytonematode species such as Heterodera avenae and Pratylenchus mediterraneus, but did not affect the beneficial entomopathogenic nematode Steinernema feltiae.  相似文献   

14.
Commercial vineyards in southern Spain were surveyed and sampled during October to December 2004 to determine the extent to which common weeds present were suitable hosts of root-knot nematodes infesting soils of those vineyards. Seven weed species commonly growing in grapevine soils in southern Spain were found infected by either Meloidogyne incognita or M. javanica: Amaranthus retroflexus (redroot pigweed), Anchusa azurea (ox-tongue), Chenopodium album (goosefoot), Erodium moschatum (musk stork’s bill), Malva rotundifolia (low mallow), Sinapis alba (white mustard), and Solanum nigrum (black nightshade). The host suitability of the weeds to root-knot nematodes was evaluated on the basis of root galling severity and nematode population densities in soil and roots. Also, the host–parasite relationship in these naturally Meloidogyne-infected weeds was examined. All the weed species in the study were considered suitable hosts for M. incognita and M. javanica because: (a) high Meloidogyne spp. populations occurred in roots and surrounding soil of the weed species; (b) the severity of root galling was high, and (c) well-established permanent feeding sites were observed in the histopathological studies of infected root tissues. In addition, this study presents the first reports of S. alba and A. azurea as hosts for M. incognita, and of E. moschatum as a new host for M. javanica, thus increasing the list of reported weed hosts for Meloidogyne spp. These results indicate that noticeable population densities of M. incognita and M. javanica can be maintained or increased in these weeds, at population levels higher than those previously reported for the same nematodes infecting grapevine roots. The weeds infesting vineyards thus represent an important source of inoculum of Meloidogyne spp., and furthermore may act as reservoirs of these nematodes which can be disseminated within or among vineyards by agricultural operations.  相似文献   

15.
Rice plants with bacterial leaf-sheath browning and grain rot were observed in Fukuoka Prefecture in Japan during the autumn seasons of 1995 and 1996. Burkholderia spp. were consistently isolated from the infected leaf sheaths and grains. These isolates were pathogenic and induced symptoms of seedling rot, grain rot, and leaf-sheath browning in rice plants, as well as in some orchidaceous plants (cymbidium, dendrobium, and oncidium leaves), gladiolus leaves, and onion bulbs. On the basis of morphological, physiological and pathological tests, and species-specific polymerase chain reaction, the isolates were identified as belonging to either Burkholderia glumae or Burkholderia gladioli. B. gladioli, as well as B. glumae, attacked rice plants after artificial inoculation and reproduced the symptoms similar to those after natural infections. We confirmed that rice is an additional natural host of B. gladioli. It is clarified that bacterial grain rot of rice is caused not only by B. glumae but also by B. gladioli.  相似文献   

16.
为了解新疆天山野果林中塞威士苹果Malus sieversii与其林下伴生植物短距凤仙花Impatiens brachycentra两种植物叶斑病病原菌的多样性及同源性,采用组织分离法获得病原菌,基于rDNA-ITS序列构建系统发育树,并进行ITS序列BLAST同源性比对,对病原菌进行鉴定分类,并依据科赫氏法则测定致病性。结果显示,从新疆新源县天山野果林中的塞威士苹果及短距凤仙花病叶上共分离得到18株菌落形态各异的病原菌,分属于2属4种,绝大多数属于半知菌亚门。其中,链格孢属Alternaria sp.为塞威士苹果和短距凤仙花叶斑病病原真菌中的优势菌群。致病性测定结果显示,其中11株病原真菌对塞威士苹果具有致病性,7株病原真菌对短距凤仙花具有致病性;塞威士苹果所有的病原真菌对短距凤仙花均有致病性,而且短距凤仙花所有的病原真菌对塞威士苹果也有致病性。推测2种植物叶斑病可能由相同来源的病原真菌引发,短距凤仙花染病加剧了塞威士苹果叶斑病暴发,可能是野果林退化的重要原因。  相似文献   

17.
In many Gram-negative plant pathogenic bacteria the type III secretion system (TTSS), encoded by hrp genes, is essential for pathogenicity in the host and induction of a hypersensitive reaction (HR) in nonhost plants. The expression of hrp genes has been suggested to be repressed in complex media, whereas it is induced in planta and under certain in vitro conditions. We recently reported that XOM2 medium allows efficient hrp expression by Xanthomonas oryzae pv. oryzae. In this study, we investigated hrp-dependent secretion of proteins by the bacteria in vitro. Using modified XOM2, in which bovine serum albumin was added and the pH was lowered to 6.0, we detected at least 10 secreted proteins and identified one as Hpa1. This is the first evidence of protein secretion via TTSS in X. oryzae pv. oryzae.  相似文献   

18.
为了解西双版纳自然保护区球孢白僵菌Beauveria bassiana的遗传多样性,采用SSR分子标记技术对西双版纳自然保护区的240株球孢白僵菌的遗传结构、基因流、菌株分化以及遗传变异相关性进行了测定和分析。结果表明,9条引物扩增240株球孢白僵菌菌株多态位点数为77个,多态位点比率为97.40%。采集的240株球孢白僵菌的总体等位基因数、有效等位基因数、Nei’s基因多样性指数和Shannon信息多样性指数分别为1.97、1.31、0.18和0.29。从寄主居群来看,鞘翅目昆虫球孢白僵菌群体遗传多样性最高,螳螂目最低,其Nei’s基因多样性指数和Shannon信息多样性指数分别为0.20和0.30、0和0;总遗传变异的29.27%存在于寄主居群间。从生境水平来看,五十五生境中球孢白僵菌群体遗传多样性最高,丫口寨生境中最低,其Nei’s基因多样性指数和Shannon信息多样性指数最高分别为0.19和0.31、0.06和0.09;总遗传变异的14.92%存在于生境居群间。从季节水平来看,球孢白僵菌秋季居群的遗传多样性最高,夏季最低,其Nei’s基因多样性指数和Shannon信息多样性指数分别为0.20和0.32、0.17和0.26;总遗传变异的3.45%存在于季节居群间。表明西双版纳自然保护区球孢白僵菌在寄主昆虫、生境分布和季节间存在明显的遗传多样性,与寄主昆虫类群的关系密切。  相似文献   

19.
A survey was carried out at nine locations in the Dutch coastal foredunes to identify the species of soil borne fungi and nematodes associated withAmmophila arenaria (Marram grass).Ammophila arenaria is a sand binding grass that is very important for the stabilization of coastal foredunes. Degeneration of the plants occurs at stabilized sites and is supposed to be caused by a combination of soil-borne fungi and nematodes. Canonical correspondence analysis (CCA) and two-way indicator species analysis (TWINSPAN) were used to examine which fungal and nematode species usually coexist in the rhizosphere of vigorous and early declining stands ofA. arenaria. In total, 47 species of fungi and 10 genera of plant-parasitic nematodes were found. According to CCA, the community of soil organisms of stands that were more than 10 years old was significantly different from recently established stands of 3 years old. Also, the community of soil organisms isolated from calcareous locations differed significantly from that of lime-poor locations. No relationship between the vigour of the plants (vigorous vs. early declining) and the soil borne species composition was found, although in roots of vigorous stands, the number of nematodes was higher than that of early declining stands. A relatively large group of soil organisms occurred generally. This group possibly contains an ubiquitous pathocomplex that cause the growth reducing effects of biotic origin which generally occur inA. arenaria. Analysis of this group of nematodes and fungi by TWINSPAN resulted in 9 different combinations of concurring soil organisms of which 5 combinations were present at all investigated locations. Two of the latter combinations contained both nematodes and fungi. The first contained three endoparasitic nematodes (Meloidogyne maritima, Heterodera spp. andPratylenchus sp.) that concurred with the fungusMucor hiemalis. The second group containedHeterodera spp.,Telotylenchus ventralis, Filenchus sp. together with the potentially plant-pathogenic fungiMicrodochium bolleyi and Fusarium culmorum, as well as the fungiMortierella sp. andTrichoderma harzianum, all in relatively high numbers.It is concluded that both CCA and TWINSPAN are valuable exploratory techniques, especially when used in combination, to detect possible combinations of soil organisms which may be involved in the degeneration ofA. arenaria. Further identifications of harmful organisms should be obtained from experiments.  相似文献   

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