抗戊唑醇禾谷丝核菌的渗透压敏感性及相对渗率变化研究

经药剂筛选和UV诱导,分别获得了抗戊唑醇的禾谷丝核菌Rhizoctonia cerealis菌株,比较了其与敏感菌株对渗透压的敏感性和经不同浓度戊唑醇处理后的相对渗率变化。在相同的渗透压环境下,敏感菌株对渗透压较抗性菌株更为敏感。不同抗性菌株间对渗透压的敏感性在低渗和中渗环境下差异不大,在高渗环境下有一定的差异;而敏感菌株只对低渗透压(1%葡萄糖)和高渗透压(8%葡萄糖)相对较为敏感。用不同浓度的戊唑醇处理后,与敏感菌株相比,抗性菌株能在较短的时间里(1 h)渗出更多的电解质,但最终前者的相对渗率要明显高于后者。用高浓度的戊唑醇处理抗性菌株后,其相对渗率明显高于低浓度处理。     

河南省小麦纹枯病菌及小麦全蚀病菌对丙环唑的敏感性

正小麦纹枯病和小麦全蚀病是河南省小麦生产上重要的土传病害,发病面积分别在300万和30万hm~2~([1,2])。近年来,由于小麦高产栽培措施(早播、密植、高肥)的推广,以及气候条件适宜、农机跨区作业等原因,两种病害的发生面积日益增大,     

The escalating threat of Rhizoctonia cerealis, the causal agent of sharp eyespot in wheat

Rhizoctonia cerealis, the causal agent of sharp eyespot on wheat, was not considered to be an important pathogen for many years. Recently, the disease has become endemic in many countries except for South America. The disease has created a new threat to world wheat production because the damage of wheat sharp eyespot has become increasingly severe. In this paper, previous studies on this pathogen, including the disease geographical distribution, pathogen identification, life cycle, symptoms, favourable environmental conditions, effects on wheat yield and control strategy, are reviewed. Such information will be helpful in management of sharp eyespot.     

敌力脱防治小麦纹枯病药效评价

敌力脱（丙环唑）和井冈霉素两种药剂采用生长速率法,室内毒力测定地小麦纹枯病菌的ＥＣ６０分别为０．３３ｍｇ／Ｌ和０．２７ｍｇ／Ｌ;ＥＣ９９为３０．０７ｍｇ／Ｌ和６４０．８２ｍｇ／Ｌ;田间施药１０ｄ防效分别为８６．７２％和７６．５８％,且在９５％水平上差异性显著。表明２５％敌力脱乳油防治小麦纹枯病优于井冈毒素。     

Visual disease and PCR assessment of stem base diseases in winter wheat

Stem base disease (eyespot, sharp eyespot and brown foot rot) was assessed visually and by the polymerase chain reaction (PCR) technique on single plants sampled at four-week intervals in two crops of winter wheat grown in the UK in 1992–3. PCR assays were conducted for Fusarium avenaceum , F. culmorum , both varieties of Microdochium nivale , both eyespot-causing species of Tapesia and Rhizoctonia cerealis . PCR diagnoses were compared with visual diagnoses at each time point. Eyespot was caused principally by T. acuformis (R-type) and developed rapidly late in the season. Visual diagnoses of eyespot were largely confirmed by PCR but T. acuformis was detected in many plants lacking eyespot symptoms. R. cerealis was detected at relatively low incidences on both sites, and sharp eyespot visual diagnoses did not correlate with the incidence of any of the pathogens assayed by PCR. Brown foot rot, caused principally by Microdochium nivale var . majus , accumulated earlier in the season than eyespot. Overall, visual diagnoses of stem base disease coincided poorly with PCR data until after growth stage (GS) 30.     

小麦纹枯病综防技术区域性决策的初步研究

运用决策分析方法, 研究了在区域性生产条件和小麦不同抗性品种布局的情况下, 如何优化综合防治技术, 以达到控害增效的目的, 为因地制宜综合防治小麦纹枯病提供了一种基于决策分析理论的技术方法途径。     

杀菌化合物对小麦纹枯菌生物测定标准初步研究

筛选小麦纹枯菌强致病力菌株R46(Rhizoctonia cerealis R46),制成不同的接种体接种中感纹枯病的小麦品种扬麦158,结果表明:用于生物测定的纹枯菌优势接种体为玉米砂与菌碟混合体;玉米砂菌丝混合体接菌量与小麦发芽率呈高度负相关。接种时期试验表明,在小麦第1叶长出前接菌,其病情指数较高;在蛭石基质营养液中总氮为15g·L~(-1)、总钾为1g·L~(-1)时小麦苗病情指数较高。离体测定多菌灵、丙环唑对小麦纹枯菌的活性表明,菌丝线性生长抑制法比菌丝干重抑制法更为敏感;活体生物测定表明,小麦纹枯菌对井冈霉素、多菌灵、丙环唑敏感。     

农用抗生素S024作用机理的初步研究

农用抗生素S024对棉花枯萎病菌和禾谷丝核菌具有明显的抗生作用。用10%的农抗S024发酵粗提液处理后,2种病原菌的细胞壁均被破坏,内含物外渗,液泡消失,菌丝体断裂,其生长能力被抑制,但是解除农抗S024的胁迫后,病原菌菌丝可恢复生长;同时,农抗S024对病原菌的孢子萌发也有一定的抑制作用。     

小麦纹枯病菌胞外蛋白酶致病机理的研究

 将小麦纹枯病菌(Rhizoctonia cerealis Vander Hoeven)产生的一种类胰蛋白酶作用于小麦细胞壁,经测定酶作用后底物中的蛋白含量及产物中羟脯氨酸含量的变化,证明了该酶能够降解寄主细胞壁结构蛋白。电镜观察该酶对活体小麦组织超微结构影响的结果显示,该酶能够降解细胞中的膜蛋白。活体内蛋白酶活性检测结果表明,小麦纹枯病菌在小麦组织内还能产生类胰蛋白酶之外的其它蛋白酶。     

小麦纹枯病菌核糖体基因内转录区序列比较

 对7个从江苏省小麦纹枯病样本分离到的丝核菌菌株,进行形态学鉴定、融合群分类和致病性测定,提取病菌的DNA,采用通用引物ITS1(TCC GTA GGT GAA CCT GCG G)和ITS4(TCC TCC GCT TAT TGA TAT GC),扩增病菌的rDNA内转录区(ITS),并对扩增产物进行了测序.用这些序列在NCBI中进行BLAST分析,得到与这些菌株亲缘关系最近的菌株序列,并明确了这些菌株的分类地位.对以上的菌株序列进行Alignment分析,结果表明,病菌的5.8S rDNA序列高度保守,而ITS区的可变性则相对较高,在双核和多核丝核菌、双核丝核菌CAG1融合群和非CAG1融合群菌株间存在差异,可用于反映菌株间的进化关系和双核丝核菌种下分类.