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1.
从水稻旱育秧病苗上分离到67个菌株 ,经鉴定分属于镰刀菌58个、腐霉菌7个、丝核菌2个。经回接测定其致病性 ,结果表明致病的镰刀菌主要是串珠镰刀菌 (Fusarium moniliforme) ;腐霉菌中主要是盐腐霉 (Pythium salinum)、间生腐霉 (P .interedium)和顶生腐霉 (P .acrogenum) ;丝核菌为立枯丝核菌 (Rhizoctonia solani)。接种试验表明串珠镰刀菌在6～8d龄幼苗的根中部侵染发病率最高 ,腐霉菌和丝核菌在一叶一心期茎基部侵染发病率最高。药剂试验表明以浸种灵(二硫氰基甲烷)、土菌消(hymexazol)、甲霜灵(metalaxyl)等种子处理加土壤处理 ,防效优于单独种子处理或土壤处理。  相似文献   

2.
新疆棉花立枯病根际拮抗放线菌的筛选   总被引：2，自引：0，他引：2  
从采集的新疆棉苗根际土样中经分离、纯化获得优势放线菌菌株95个,采用平板对峙培养法对立枯丝核菌(Rhizoctonia solani)进行根际拮抗放线菌的筛选。结果表明,共获得根际拮抗放线菌菌株22株,其中菌株M-1抑菌谱广,抑菌活性强,热稳定性较好,是一株具有良好应用潜力的防治棉花立枯病的生防菌。  相似文献   

3.
 从马铃薯根际土壤中分离筛选得到对立枯丝核菌有较强拮抗作用的菌株XC-1,对其进行鉴定及生防特性分析,并评价其对马铃薯黑痣病的生防效果。形态学、16S rDNA和gyrB基因序列分析以及生理生化检测结果表明,XC-1菌株为枯草芽孢杆菌(Bacillus subtilis)。XC-1菌株具有产纤维素酶、蛋白酶及嗜铁素和HCN能力。同时,具有产生脂肽类活性物质的能力。其发酵液能导致立枯丝核菌菌丝断裂、折叠、膨大等,进而抑制其生长。田间试验结果表明,XC-1在马铃薯苗期、花期以及收获期均有防效,在收获期生防效果达到54.51%。同时,经菌株XC-1菌悬液接种处理后的马铃薯产量与对照组相比增加了22.02%。XC-1是马铃薯黑痣病生防制剂的潜力菌株,具有良好的开发和应用价值。  相似文献   

4.
为筛选出对立枯丝核菌Rhizoctonia solani Kühn具有优良防效的拮抗菌株。本研究从关防风根际土壤中分离纯化出156株细菌,采用平板对峙法测定菌株SC-32和SC-127对立枯丝核菌均有良好拮抗效果,且兼具广谱抑菌能力;抗生素标记法测定菌株SC-32和SC-127接种35 d后在土壤中含菌量仍能保持2.93×107和7.83×106CFU/g;通过盆栽试验研究结果表明,菌株SC-32和SC-127对关防风立枯病的防治效果为60.53%和65.89%,高于菌剂和农药处理。通过形态学、生理生化特征、16S rDNA基因序列进行分类学鉴定确定菌株SC-32和SC-127均为贝莱斯芽胞杆菌Bacillus velezensis。  相似文献   

5.
大豆纹枯病菌具有典型的Rhizoctonia solani特性,其无性世代形态、培养性 状、致病性与水稻纹枯病菌及棉立枯病菌有明显的差异;不侵染辣椒、普通烟,与棉花立枯病菌、水稻纹枯病菌不发生菌丝融合现象,该菌与水稻纹枯病菌能交互侵染大豆、水稻,稻-豆轮作将加重纹枯病的发生。大豆纹枯病田间流行曲线属“S”型,在始发期连续2次施用井岗霉素(50ppm)或(40％)多菌灵(500倍),防效可达85％以上。  相似文献   

6.
新疆北疆棉田立枯丝核菌不同菌丝融合群致病力的研究   总被引：1，自引：0，他引：1  
从新疆北疆棉区采集了典型的棉花立枯病病苗及棉田土标样686份,按常规分离方法分离得到399个分离物,从中鉴定出272个纯化的立枯丝核菌(Rhizoctonia solani Kühn)菌株。用标准菌株,通过载玻片菌丝融合试验测定,将纯化的272个菌株划归为3个菌丝融合群:即AG-2、AG-4和AG-5,分别占总菌株的6.24%、84.2%和1.1%。另有23个菌株不与任何标准菌株融合,占8.46%,说明新疆北疆棉田立枯丝核菌的优势菌系是多核丝核菌的AG-4融合群。通过从10种不同配方培养基中筛选效果好的麦芽蛋白胨(MPDA)配方培养基(Ⅱ)进行对峙培养,将纯化获得的272个丝核菌菌株,划分为6个不同的营养亲和群。将多核的不同菌丝融合群及其各营养亲和群代表菌株在3种不同主栽棉花品种上(每品种都加不接菌的对照)进行温室盆栽致病力测定,结果以AG-4对棉花的致病力最强,其次是非融合类,AG-2和AG-5虽致病,但并不致死苗,其平均病指数分别为94.9、81.4、53.1、43.5。  相似文献   

7.
水稻纹枯病是严重影响水稻生产的真菌病害,水稻相对病斑高度法作为评估立枯丝核菌AG-1 IA致病力的传统方法,需要将水稻培养至分蘖末期或抽穗期,再进行活体接种,耗时耗力,且试验条件不易控制。本研究以水稻相对病斑高度法(活体接种)为对照,利用水稻离体叶鞘法和离体叶片法测定了水稻纹枯病菌致病力和粗毒素活性,比较活体接种法与离体接种法的相关性。结果表明水稻离体叶片法、水稻离体叶鞘法和水稻相对病斑法测定致病力和粗毒素活性结果均呈显著正相关,水稻离体叶片法和离体叶鞘法测定结果能够准确反映立枯丝核菌AG-1 IA的致病力和粗毒素活性,离体评估方法操作方便,试验条件易于控制。因此,水稻离体叶片法、叶鞘法可以替代活体接种法作为测定立枯丝核菌AG-1 IA致病力和粗毒素活性的方法。水稻离体叶片法、叶鞘法与活体接种法结合起来可作为测定立枯丝核菌AG-1 IA毒素活性测定的新方法。本研究的结果还表明,水稻不同组织对水稻纹枯病菌毒素敏感性不同,水稻的叶鞘组织比叶片组织对纹枯病菌敏感。由于粗毒素的致病力与活体菌株接种的致病力存在显著差异,因此纹枯病菌毒素以外的致病因子,也是不容忽视的。在定量分析立枯丝核菌AG-1 IA与水稻的互作中,需要将不同水稻的组织进行区分,才能更加精准地了解互作机制。  相似文献   

8.
为获得对小麦条锈病具有生防潜力的菌株,通过土壤稀释法和皿内拮抗法分离筛选对小麦条锈菌Puccinia striiformis f.sp.tritici（Pst）有良好拮抗作用的菌株,基于形态学观察、生理生化特性和16S rDNA系统发育分析对其进行分类鉴定,测定其抑菌活性、抑菌谱及生防特性,并通过盆栽试验进一步验证其生防潜力。结果显示,筛选出1株菌株XH可以显著抑制Pst夏孢子萌发,结合形态学和分子生物学特征将其鉴定为直丝紫链霉菌Streptomyces rectiviolaceus;菌株XH发酵滤液对Pst夏孢子的萌发抑制率为94.36%,致死率达91.53%,且该菌株对测试的7种常见植物病原菌均有抑制作用,可以分泌淀粉酶、蛋白酶、纤维素酶和嗜铁素,具有固氮作用;盆栽试验结果显示,菌株XH的菌体悬浮液和发酵滤液可显著降低小麦叶片的Pst侵染量,对小麦条锈病的防治效果分别为54.26%和67.22%。表明菌株XH作为小麦条锈病生防菌株具有较好的开发应用潜力。  相似文献   

9.
玉米内生菌L10的分离、鉴定及拮抗活性   总被引：2，自引：1，他引：2  
为获得对玉米茎腐病主要病原菌禾谷镰孢Fusarium graminearum有明显拮抗作用的玉米内生菌,采用平板对峙法从成熟健康玉米茎秆中筛选禾谷镰孢拮抗菌株,并分析其抗菌谱;通过形态特征、生理生化特性及16S rDNA序列分析进行菌种鉴定;利用盆栽生防试验检测其对玉米茎腐病的防治效果。结果表明,共分离获得了164株玉米内生细菌菌株,其中L10菌株对禾谷镰孢具有较好的抑制效果,抑菌圈半径达1.68 cm;该菌对玉米大斑病菌Setosphaeria turcica、层出镰孢F. proliferatum、禾谷镰孢F. graminearum、拟轮枝镰孢F. verticilliodes、玉米弯孢叶斑病菌Curvularia lunata、玉米小斑病菌Bipolaris maydis、立枯丝核菌Rhizoctonia solani、茄链格孢Alternaria solani共8种植物病原菌均有拮抗作用,尤其对禾谷镰孢抑制效果最佳;结合形态特征、生理生化性质及16S rDNA序列分析,将L10菌株鉴定为多粘类芽胞杆菌Paenibacillus polymyxa。L10菌株脂肽类物质对禾谷镰孢菌具有较好的抑制活性,且盆栽生防试验结果显示该菌株对玉米茎腐病具有一定的防治效果。表明菌株L10对玉米镰孢茎腐病的防治具有一定潜力。  相似文献   

10.
我国小麦纹枯病病原学的初步研究   总被引：31，自引：4，他引：31  
从北京、江苏、浙江、安徽、山东、河南、江西、四川、贵州、陕西及甘肃等11个省市采集到的小麦纹枯病病株上共分离出43个丝核菌分离物,分别属于双核丝核菌CAG-1、CAG-2、CAG-3、CAG-5、CAG-6,以及多核丝核菌AG-2-1和AG-5等7个不同的菌丝融合组;各组分离物的数目依次为27、2、1、3、1、2和4个。致病性测定结果表明,引起我国小麦纹枯病的主要病原物是禾谷丝核菌(Rhizoctonia cerealis)中的第一菌丝融合组(CAG-1),但立枯丝核菌(R.solani)中的第五菌丝融合组(AG-5)亦可致病。文中讨论了小麦纹枯病病原的复杂性,复合侵染,微侵染,菌丝融合组中致病力差异和生物防治方法的应用前景等问题;对小麦纹枯病病原学研究在理论和实践上的意义进行了阐述。  相似文献   

11.
为获得对水稻纹枯病有生防潜力的菌株,从湖北省恩施土家族苗族自治州植物根际土壤中分离获得菌株,筛选对水稻纹枯病菌有拮抗作用的菌株,并测定其发酵液的抑菌活性、抑菌谱及生物学特性;基于形态学特征、生理生化特征及分子生物学特征对其进行分类鉴定,并通过离体叶片、室内盆栽和田间试验进一步评价其生防潜力。结果显示,从根际土壤中共分离获得162株菌株,其中生防菌株E12对水稻纹枯病菌的抑制率最高,达94.93%,且该菌株对常见的12种植物病原菌均有抑制作用,抑制率在59.84%~93.14%之间;生防菌株E12能分泌蛋白酶、嗜铁素和淀粉酶,具有固氮及形成生物被膜的能力;结合形态学特征、生理生化特征及分子生物学特征,将菌株E12鉴定为越南伯克霍尔德氏菌Burkholderia vietnamiensis;生防菌株E12处理离体水稻叶片后,其相对病斑长度较对照显著减小,对水稻纹枯病的室内盆栽和田间防治效果分别为62.51%和67.78%。表明越南伯克霍尔德氏菌E12在防控水稻纹枯病方面有较好的潜力。  相似文献   

12.
Serratia marcescens strain B2 is an antagonistic bacterium that produces the red-pigmented antibiotic prodigiosin and suppresses rice sheath blight caused by Rhizoctonia solani AG-1 IA. Rice sheath blight disease was suppressed when plants were inoculated with this bacterium an hour before pathogen inoculation but not when plants were treated 4 weeks before pathogen inoculation. In both cases the bacteria were detected in the rice rhizosphere 4 weeks after inoculation. Bacteria isolated from the rice plant and rhizosphere inhibited biosynthesis of prodigiosin in S. marcescens strain B2. We suggest that bacteria isolated from rice plants and rhizospheres mediate the suppression of antibiotic production of biological control agents and that such suppression is common under field conditions.  相似文献   

13.
水稻纹枯病菌拮抗细菌的筛选及鉴定   总被引：3，自引：0，他引：3  
为获得对水稻纹枯病有生防效果的拮抗细菌,从江苏南京、徐州和常州等地采集的土样中分离细菌分离物1914株,采用平板对峙法筛选获得70株对水稻纹枯病菌有较强抑菌活性的分离物,其中11株对5种水稻病害病原菌均有抑制作用;对11株拮抗菌进行田间防效和室内促生试验,测定菌株分泌的抑菌物质和促生物质,并进行种属鉴定.结果表明,拮抗菌对水稻纹枯病的盆栽和田间小区防效在48.41％和43.03％以上;均可产生蛋白酶与嗜铁素,而不产生几丁质酶,除XF-174外其余10个菌株均可产生纤维素酶;对水稻苗株高和鲜重具有促生作用,并均可产生赤霉素(GA3);除ZF-273和XF-174外的9个菌株可产生吲哚乙酸(IAA),且细菌发酵液中IAA和GA3含量与水稻株高和鲜重的增长率呈正相关.结合各菌株形态特征、生理生化特性和16S rDNA与gyr-B序列分析结果,鉴定SF-181为枯草芽胞杆菌Bacillus subtilis,XF-174为荧光假单胞菌Pseudomonas fluorescens,其余9个菌株为解淀粉芽胞杆菌B.amyloliquefaciens.  相似文献   

14.
The population structure of Rhizoctonia solani AG-1 IA causing rice sheath blight from India was evaluated for 96 isolates using seven RFLP loci. Nineteen of the isolates did not hybridise to R. solani AG-1 IA RFLP probes and rDNA analyses subsequently confirmed that they were either Ceratobasidium oryzae-sativae isolates or another Rhizoctonia sp. The population structure of the remaining 77 R. solani AG-1 IA Indian isolates was similar to that of a previously characterized Texas population. Clonal dispersal of R. solani AG-1 IA in India was moderate within fields and no clones were shared among field populations. Low levels of population subdivision and small genetic distances among populations were consistent with high levels of gene flow. Frequent sexual reproduction was indicated by the fact that most populations were in Hardy–Weinberg equilibrium (HWE). The two loci (R68 and R111) that deviated significantly from HWE showed an excess of heterozygosity. Although Texas and Indian populations were geographically very distant, they exhibited only moderate population subdivision, with an FST value of 0.193.  相似文献   

15.
Phytophthora blight of pepper caused by Phytophthora capsici has devastating consequences when combined with other pathogens, including Rhizoctonia solani, Fusarium oxysporum, and Fusarium solani. In order to develop a field-effective biocontrol strategy against Phytophthora blight of pepper, three chitinolytic bacteria, Serratia plymuthica strain C-1, strongly antagonistic to P. capsici, Chromobacterium sp. strain C-61, strongly antagonistic to R. solani, and Lysobacter enzymogenes strain C-3, antagonistic to R. solani and Fusarium spp., were selected. In pot studies, application of cultures combining the three bacterial strains effectively suppressed Phytophthora blight more than application of any single bacterial strain. Bioformulations developed from growth of the strains in a simple medium containing chitin under large batch conditions resulted in effective control in field applications. Efficacy of the bioformulated product depended on both the dose and timing of application. Although the undiluted product suppressed Phytophthora blight under all field conditions, a 10-fold diluted product was effective in solar-sterilized greenhouses and in fields with crop rotation. These results suggest that the developed product could be a new effective system to control Phytophthora blight disease in pepper.  相似文献   

16.
Rhizoctonia solani causes pre- and post-emergence damping-off, root and hypocotyl rot and foliar blight in soybean. Foliar blight has resulted in yield losses of 31–60% in north and northeast Brazil. The aim of this study was to characterize isolates of R. solani associated with soybean in Brazil. Among 73 Rhizoctonia isolates examined, six were binucleate and 67 were multinucleate. The multinucleate iso1ates were characterized according to hyphal anastomosis reaction, mycelial growth rate, thiamine requirement, sclerotia production, and RAPD molecular markers. Four isolates that caused hypocotyl rot belonged to AG-4 and using RAPD analysis they grouped together with the HGI subgroup. Another isolate that caused root and hypocotyl rots was thiamine auxotrophic, grew at 35°C, and belonged to AG-2-2 IIIB. All 62 isolates that caused foliar blight belonged to AG-1 IA. RAPD analysis of R. solani AG-1 IA soybean isolates showed high genetic similarity to a tester strain of AG-1 IA, confirming their classification. The teleomorph of R. solani, Thanatephorus cucumeris was produced in vitro by one AG-1 IA isolate from soybean. The AG-4 and AG-2-2 IIIB isolates caused damping-off and root and hypocotyl rots of soybean seedlings cv. FT-Cristalina, under greenhouse conditions. The AG-2-2 IIIB isolate caused large lesions on the cortex tissue, that was distinct from the symptoms caused by AG-4 isolates. The AG-1 IA isolates caused foliar blight in adult soybean plants cv. Xingu under the greenhouse and also in a detached-leaf assay.  相似文献   

17.
The response of key regulatory enzymes of the pentose phosphate and glycolytic pathways in disease development was assessed in genetically-related rice plants resistant and susceptible to the sheath blight fungus, Rhizoctonia solani. The plants were grown and maintained under greenhouse conditions and inoculated at 50% flowering. Uninoculated healthy plants served as controls. The activities of pentose phosphate pathway enzymes (glucose-6 phosphate dehydrogenase and 6-phosphogluconate dehydrogenase) increased more than two-fold in both the resistant and susceptible plants. Activities of ATP- and pyrophosphate-dependent phosphofructokinase and phosphoenolpyruvate phosphatase increased in infected plants while activity of phosphoenolpyruvate carboxylase in infected plants was lower than in the healthy plants. Furthermore, for enzymes with increased activity, the levels were higher in the resistant line than in the susceptible line. The enhancement of the enzyme activities correlated well with the post infection period. These data suggest that altered carbohydrate metabolism in sheath blight infections may play an important role in modulating the rice plant's response to infection. The isolation of an infection-induced gene encoding a basic enzyme of pentose phosphate and glycolytic pathways could be used to develop plants with more resistance towards sheath blight disease.  相似文献   

18.
Leaf blight, sheath blight, and web blight are major diseases caused by Rhizoctonia species on both Fabaceae and Poaceae plant hosts in the Brazilian Amazon agroecosystem. To determine the diversity of Rhizoctonia species associated with foliar diseases on fabaceous (cowpea and soybean) and poaceous (rice and signal grass [Urochloa brizantha]) hosts, a broad survey was conducted in Pará, Rondônia, Roraima, and Mato Grosso, in the Amazon, from 2012 to 2013. We extended our survey to Cerrado areas of Mato Grosso, and the lowlands of Paraíba Valley, in São Paulo, where these Rhizoctonia foliar diseases have not been reported so far. Our findings revealed that these diseases are caused by a diversity of Rhizoctonia solani AG-1 complex. We detected that R. solani AG-1 IA (sexual phase Thanatephorus cucumeris) was the predominant pathogen associated with signal grass leaf blight and collar rot diseases in the Amazon, especially in Rondônia and northern Mato Grosso. In addition, a subgroup of R. solani (AG-1 IF), not previously reported in Brazil, was associated with leaf blight on cowpea and soybean, in Roraima. Another subgroup (AG-1 ID) was also detected in Roraima. In Mato Grosso Cerrados we did not find any of the major Rhizoctonia foliar pathogens. Instead, R. oryzae (Waitea circinata) was the predominant species associated with a collar rot on U. brizantha. In the lowlands of São Paulo, R. oryzae-sativae (Ceratobasidium oryzae-sativae) was the predominant pathogen detected causing the rice sheath spot disease.  相似文献   

19.
A total of 304Rhizoctonia solani isolates and 60 binucleateRhizoctonia-like fungi were recovered from stems and tubers of infected potato plants over a 2-yr period in northeast Turkey.R. solani isolates were identified to 11 anastomosis groups (AGs): AG-1 (0.66%), AG-2-1 (5.6%), AG-2-2 (0.99%), AG-3 (83.9%), AG-5 (4.6%), AG-6 (0.66%), AG-8 (1.32%), AG-9 (0.33%), AG-10 (1.32%), AG-12 (0.33%), and AG-13 (0.33%). In the greenhouse tests, most of the AG-3 isolates were significantly more virulent than isolates belonging to other AGs on potato cv. Batum. Isolates of other anastomosis groups differed in their virulence. Results indicated that AG-3 is an important pathogen on potatoes grown in the study area. Five of 22 commercial and local potato cultivars evaluated for their reaction toR. solani AG-3 isolates (TP-2) under greenhouse conditions were highly resistant; the remaining cultivars exhibited different levels of susceptibility to the pathogen isolate. http://www.phytoparasitica.org posting July 14, 2005.  相似文献   

20.
The aim of the study is to investigate the biocontrol mechanisms of Trichothecium roseum MML003 against the rice sheath blight (ShB) pathogen, Rhizoctonia solani as the former exhibited strong antagonistic activity against the latter. It has been found that T. roseum MML003 did not show any hyperparasitic interaction against R. solani. Further, it did not produce siderophores and hydrogen cyanide. However, the culture filtrate of T. roseum MML003 strongly inhibited the mycelial growth and sclerotial formation, its germination and viability, which proved that the biocontrol activity is antibiosis-mediated. The extracellular crude antifungal metabolites of T. roseum MML003 were thermo and photo-stable. Potted plant experiment showed that the crude metabolites of T. roseum MML003 effectively reduced the ShB disease in rice up to 47.7%. Thus, this study assumes significance as it provided further scope for the identification of antifungal metabolites from T. roseum MML003 and their possible use against sheath blight disease of rice.  相似文献   

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