Cloning of DNA fragments specific to the pathotype and race of <Emphasis Type="Italic">Verticillium dahliae</Emphasis>

Japanese isolates of Verticillium dahliae, a causal agent of wilt disease in many plants, are classifiable into pathotypes based on their pathogenicity. Because these pathotypes are morphologically indistinguishable, establishing a rapid identification method is very important for the control of this pathogen in Japan. For cloning DNA fragments that are useful for identification and specific detection of V. dahliae pathotypes, we performed random amplified polymorphic DNA (RAPD) analyses using various isolates. One polymerase chain reaction (PCR) product, E10-U48, was specific to isolates pathogenic to sweet pepper. The other product, B68-TV, was specific to race 1 of isolates pathogenic to tomato. The specificity of these sequences was confirmed by genomic Southern hybridization. Further analyses revealed that the region peripheral to B68-TV obtained from the genomic DNA library includes the sequence specific to all isolates pathogenic to tomato (races 1 and 2). Moreover, sequence tagged site (STS) primers designed from B68-TV and its peripheral region showed race-specific and pathotype-specific amplification in a PCR assay. The probes and primers obtained in this study are likely to be useful tools for the identification and specific detection of pathotypes and races of V. dahliae. The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under accession number AB095266.     

石河子地区棉花黄萎病菌致病型监测研究

对石河子地区采集的黄萎病菌代表性菌系进行生物学特性及致病性分化研究,结果表明:棉花黄萎病菌菌落形态为圆形,大多数菌落的中央为白色棉絮状的菌丝而较凸起,供试菌系均可形成微菌核;病菌在15~30℃条件下均可生长,最适生长温度为25℃,超过33℃则不能生长,对高温具有一定的耐受性;依据鉴别寄主法测定结果,石河子地区的棉花黄萎病菌可分为中、弱2种致病型,其中以弱致病类型为主。     

Relation between pathogenicity and genetic variation within <Emphasis Type="Italic">Plasmodiophora brassicae</Emphasis>

The relation between diversity of pathogenicity on clubroot-resistant (CR) cultivars of Chinese cabbage (Brassica rapa subsp. pekinensis) bred in Japan and DNA polymorphisms in 17 populations of Plasmodiophora brassicae from cruciferous plants was examined by inoculation tests and random amplified polymorphic DNA (RAPD) analysis using 18 arbitrary primers. Four pathotypes (A–D) were identified after inoculation of six CR cultivars of Chinese cabbage in the 17 populations from cruciferous crops. A relatively high level of genetic diversity was also detected among these populations in the RAPD analysis. Although the four pathotypes could not be clearly differentiated using the RAPD data, most populations of three pathotypes had a consistent location on the dendrogram. All pathotype B (virulent on five cultivars except Utage 70) and D (avirulent on all cultivars) populations, which were common in incompatible interactions with cv. Utage 70, were located in a single subcluster. All five pathotype C populations (virulent only on cv. Utage 70) except for one population grouped in another single subcluster. Because four pathotype A populations (virulent on all six cultivars, races 4 and 9) fell in different subclusters, the populations may be genetically polyphyletic. Populations from cruciferous weed Cardamine flexuosa differed remarkably from those from cruciferous crops in pathogenicity on common cultivars of Chinese cabbage and turnip and C. flexuosa, but they grouped in a single cluster with all race 9 populations from crops. Race 9 populations from crops may thus be closely related to populations from the weed rather than to races 1 and 4 from crops.     

Application of pathogen surveys,disease nurseries and varietal resistance characteristics in an IPM approach for the control of wheat yellow rust

The present paper presents the rationale for the use of pathogen surveys, inoculated and non-inoculated disease nurseries and varietal resistance characteristics in an integrated approach to control wheat yellow rust in Denmark. The non-inoculated disease observation plots, which gave valuable information about yellow rust at the year, site and variety level, served as the primary sample source for the pathogen survey revealing pathogen virulence dynamics. This survey was also the main source for isolates of new pathotypes, a prerequisite for the assessment of the resistance characteristics of varieties and breeding lines in inoculated nurseries, and the postulation of race-specific resistance genes. A simple grouping of varieties into four categories with respect to resistance to the current yellow rust population proved robust, and this grouping was used as a determinant in a web-based decision support system for pesticide applications in cereals, Crop Protection On-line (CPO). The interplay between the different research and survey activities in the integrated pest management (IPM) approach demonstrated the need for a coherent and long-term involvement at all stages from plant breeding to the official variety approval system, extension service and research in disease epidemiology and resistance genetics.     

2004年甘肃省小麦条锈菌生理小种变异监测

对2004年采自甘肃省天水、陇南、定西、兰州、临夏及四川省绵阳、屏山、温江等地的276份小麦条锈菌标样进行监测,结果表明:共监测出29个生理小种及致病类型。小种消长变化总趋势与2003年基本相同,继续以Hybrid46及水源11致病类群为主,水源14类型仍为第1位流行小种,出现频率为29.3%。条中32号为第2位流行小种,出现频率已由2003年的12.4%上升到2004年的25.0%。水7、水4、居第3、4位,频率分别为8.3%、7.6%。所不同是条中31号仍为次要小种,但频率有所上升。其它小种出现频率基本不变。Yr9、Yr3b 4b、Yrsu为我省的主要致病基因。抗锈育种应以条中32号、水14、水4为主,兼顾Hybrid46和水源11致病类群中其它致病类型。     

麦类作物对燕麦胞囊线虫抗病性遗传研究进展

概述了燕麦胞囊线虫致病型、麦类人地燕麦胞囊线虫抗病必一鉴定方法，介绍了迄今世界上在麦类作物对禾谷囊线虫抗病育种中已选育和生产上正推广的一些主要抗病基因（品种），阐述了中国燕麦胞囊线虫致病型（特别对rDNA中ITS区的PCR－RFLP分析，所获得的一个新的ITS类型－ITS C)以及麦类作物品种抗性的研究现状，这对中国开展针对燕麦胞囊线虫的抗病育种及相关的研究有重要的意义。     

Electrophoretic karyotyping and mapping of pathotype-specific DNA sequences in Japanese isolates of <Emphasis Type="Italic">Verticillium dahliae</Emphasis>

The chromosome number and electrophoretic karyotype of Japanese isolates of Verticillium dahliae were investigated. In a genomic Southern blot analysis of seven isolates probed with a telomere consensus sequence (TTAGGG)₅, 12 or 14 bands were observed. Furthermore, pulsed-field gel electrophoresis (PFGE) of these isolates revealed five or six chromosomal bands. A band (approx. 3.5 Mbp) common to all isolates apparently contained more than two chromosomes. From these results, we concluded that each isolate’s chromosome number is six (an eggplant pathotype isolate) or seven (all isolates of tomato and sweet pepper pathotypes). Although the chromosome sizes differed among isolates, karyotypes were similar within tomato and sweet pepper pathotypes. A small chromosome (approx. 1.8 Mbp) was observed only in the sweet pepper pathotype. Subsequent PFGE-Southern hybridization analyses revealed that the three DNA fragments specific to tomato pathotype are located on the same chromosome. These results suggest that the tomato-pathotype-specific DNA sequences might coexist on one chromosome.     

基于稻瘟菌毒性相关基因的指纹类型与致病型关系分析

本研究根据8对稻瘟菌毒性相关基因序列同源性设计其特异性引物,通过PCR扩增分析单孢分离培养的不同地理来源的44个菌株,获得其指纹。利用18个丽江新团黑谷（LTH）单基因鉴别寄主对其中的31个菌株进行致病型鉴定;用SPSS11．5聚类分析,根据31个菌株在18个LTH NILs上的抗感反应,在Lable No．10的位置,将菌株分为7种致病类型。将上述的两种不同的聚类结果进行相关性分析,发现通过毒性相关基因的特异性引物划分出的指纹类型与用菌株在LTH NILs的抗感反应划分出的致病型之间不存在——对应关系。     

稻瘟病菌群体遗传结构及致病型的研究进展

综述了稻瘟病菌群体遗传学研究的重要性及针对稻瘟病菌群体结构特征的研究方法,分析了稻瘟病菌群体遗传宗谱与致病型的相互关系,并探讨了在稻瘟病菌群体结构研究过程中需要加强的方面.     

安徽省水稻白叶枯病菌致病型测定

１９９７、１９９８年分别对安徽省２８个县市的主栽稻区分得的３０个菌株,在安徽农业大学农场（无病区）进行田间成株期测试,用全国统一的ＩＲ－２６、Ｔｅｔｅｐ、Ｊａｖａ－１４、南粳－１５、金刚－３０ ５个鉴别品种,于孕穗期剑叶剪叶接种测定。结果表明,安徽水稻白叶枯病菌,除肥东菌株（Ｘｏ－０１）与怀远菌株（Ｘｏ－７１）属Ⅲ型外,多数菌株属Ⅱ型,而皖南和沿江稻区菌株致病力弱,多属０－ Ⅰ型。