香蕉枯萎病菌致病力分化与ISSR遗传多样性分析

香蕉枯萎病是一种破坏香蕉维管束的全株性土传病害。本研究旨在探讨香蕉枯萎病菌致病力分化和遗传多样性。以30株采自我国广西的香蕉枯萎病菌,16株分别来自澳大利亚和我国广东、海南、福建、云南等地的香蕉枯萎病菌为对象,采用伤根灌淋法测定香蕉枯萎病菌的致病力,然后用筛选到的ISSR引物对46个香蕉枯萎病菌菌株和4个对照菌株(3个非致病性尖孢镰刀菌和1个茄腐镰刀菌)进行ISSR遗传多样性分析。结果显示,分离到广西香蕉枯萎病菌1号生理小种(FOC1)8株,致病力强、中、弱类型比例分别为62.5%、12.5%和25%;广西香蕉枯萎病菌4号生理小种(FOC4)22株,致病力强、中、弱类型比例分别为18.18%、63.64%和18.18%。14条ISSR引物扩增出237个条带,多态性条带161个,多态性比例为67.93%,遗传相似系数0.76～0.96。聚类分析显示,以遗传距离0.80为阈值时菌株被分为8个类群,所占比例分别为4%、10%、60%、16%、4%、2%、2%、2%。第三类群全部为香蕉枯萎病菌4号生理小种。第一、二、四和五类群总量的70.59%为香蕉枯萎病菌1号生理小种。第八类群为香蕉枯萎病菌3号生理小种。结果表明,在香蕉枯萎病菌与寄主协同进化中,广西的FOC1和FOC4出现明显致病力分化。1号生理小种的遗传多样性比4号生理小种丰富。广西香蕉枯萎病菌4号生理小种与海南、广东的FOC4遗传相似性较高。香蕉枯萎病菌生理小种类型与遗传多样性相关。致病力变异与遗传多样性无相关性。研究结果对香蕉枯萎病菌种群扩张机制探讨、遗传动态分析以及有效防控措施的制定具有一定的指导意义。     

河北省棉花枯萎菌遗传多样性及致病力分化

为明确河北省棉花枯萎菌（Fusarium oxysporum f.sp.vasinfectum, FOV）变异及致病力分化情况,利用AFLP技术对采自河北省的75株FOV和3号、7号、8号生理小种的标准菌株进行遗传多样性分析,并比较了不同AFLP类群菌株对棉花品种冀棉11号的致病力差异。结果表明,78株FOV可划分为4个AFLP类群（AFLP groups, AGs）,AGsⅠ为3号生理小种,AGsⅡ为8号生理小种,AGsⅢ包括7号生理小种和67株田间采集菌株,AGsⅣ包括8个田间采集菌株,该类群菌株与3号、7号、8号生理小种遗传差异较大。致病力初步测定表明,3号、7号、8号生理小种的标准菌株属中等致病力水平,而田间采集的75株枯萎菌菌株致病力存在明显差异,其中强致病力菌株占66.67%,中等致病力菌株占21.33%,弱致病力菌株占12%。表明河北省FOV群体遗传结构复杂,有遗传差异较大的新菌株出现,而且同一生理小种菌株之间存在显著的致病力分化。     

甘肃省玉米大斑病菌生理小种结构组成与交配型测定

为了明确甘肃玉米大斑病菌生理小种与交配型的结构组成,采用单基因鉴别寄主测定了甘肃4个典型生态区57株玉米大斑病菌的抗、感反应型,对峙培养显微观测法测定了它们与标准菌株杂交是否产生有性态子囊壳。结果表明,甘肃玉米大斑病菌生理小种结构组成十分复杂,57株病菌中共发现0、1、12、23、123、N、1N、2N、3N、123N共10个生理小种,0号以61.40%分布频率成为优势生理小种,1号以17.54%分布频率成为次优势生理小种,23号生理小种出现频率仅为5.26%、123和N号生理小种出现频率仅为3.51%,12、1N、2N、3N、123N生理小种出现频率仅为1.75%,4个典型生态区中河西灌溉绿洲生态区生理小种结构组成最为复杂,15株病菌中共检出0、1、N、12、1N、2N、3N、123N 8个生理小种,中部干旱雨养、陇东半湿润半干旱和南部湿润生态区生理小种结构组成相对简单,42株病菌共检出0、1、23、123和N号5个生理小种。相对而言,甘肃玉米大斑病菌交配型结构组成简单,57株病菌中共检出A型22株、a型24株, Aa型11株,分布频率分别为38.6%、42.1%和19.3%;其中河西灌溉绿洲、中部干旱雨养和陇东半湿润半干旱生态区45株病菌共检出18株A型、18株a型和9株Aa型,A∶a比例完全符合1∶1,南部湿润生态区12株病菌共检出4株A型、6株a型和2株Aa型,A∶a比例小于1∶1。     

香蕉枯萎病菌RAPD分析及4号生理小种的快速检测

 用随机扩增多态性DNA(RAPD)技术,对采自广东、广西的香蕉和粉蕉上的30个香蕉枯萎病菌(Fusarium oxysporum f.sp.cubense)菌株和3个其它尖孢镰刀菌专化型的菌株进行比较及聚类分析。在遗传相似系数0.67时,可将供试菌株划分为3个RAPD群(RGs),其中香蕉枯萎病菌4号生理小种(FOC4)共15个菌株属于RGⅠ,1号生理小种(FOC1)共15个菌株属于RGⅡ,供试的其它尖孢镰刀菌专化型的3个菌株则属于RGⅢ。这说明香蕉枯萎病菌和供试3个其它专化型菌株与致病性间存在明显的相关性。1号生理小种内菌株间的遗传分化大于4号生理小种内菌株间的遗传分化。从90条RAPD随机引物中筛选出2条引物可产生4号生理小种的RAPD标记2个。将这2个RAPD标记电泳切胶回收、克隆及测序,并根据这2个特异片段序列设计SCAR上下游特异引物,通过对30个菌株的PCR扩增检验,其中一个RAPD标记成功地转化为SCAR标记,初步建立了以此为基础的4号生理小种快速检测技术,其检测灵敏度为2 ng新鲜菌丝。对采自不同地区的显症样品、吸芽、室内接种未显症的香蕉苗以及发病的香蕉植株不同部位进行检测,能够准确灵敏地鉴定出4号生理小种,从而为香蕉枯萎病菌的快速检测及防治奠定了基础。同时,快速检测结果发现,田间发病植株果柄的各部位及果实内并没有枯萎病菌的存在。     

大豆疫霉根腐病菌单游动孢子的毒性遗传与变异

 采用离体叶柄伤口接种法测定大豆疫霉根腐病菌44号生理小种单游动孢子连续3代或4代分离后代的毒性,结果表明:从S1中选择与亲本相比毒性不发生变异的1号单游动孢子菌株(44号生理小种)和变异最大的30号单游动孢子菌株(1号生理小种)继续分离2代或3代,单游动孢子毒性变异趋势主要是从44号生理小种变异为3号生理小种,也有变异成毒性公式为7或1a,7的单游动孢子。大豆疫霉根腐病菌无性世代毒性变异几率很高,多数单游动孢子毒性在分离后代中都发生变异,产生不同的小种或毒性公式,并且毒性变异基本不能稳定遗传。     

甘蓝枯萎病菌1号和2号生理小种的快速检测与鉴定

 甘蓝枯萎病菌生理小种传统鉴定方法费时费力,不能满足生产的要求,因此需要建立一种快速、可靠的分子检测技术。本研究在甘蓝枯萎病菌1号和2号生理小种基因组测序的基础上,通过比较基因组学方法筛选1、2号生理小种各自的特异基因片段并设计引物,并分别以10个甘蓝枯萎病菌1号生理小种菌株、2个2号生理小种菌株、7个尖孢镰刀菌其他专化型菌株及4个外围菌株DNA为模板进行常规PCR扩增,筛选出甘蓝枯萎病菌1号和2号生理小种特异性引物,同时引入尖孢镰刀菌通用引物W106R/W106S,建立起一步三重PCR检测甘蓝枯萎病菌1、2号生理小种的分子检测技术。结果表明,该分子检测技术实现了在一次PCR反应中快速、准确地同步检测出甘蓝枯萎病菌DNA、罹病甘蓝组织和土壤中的甘蓝枯萎病菌1号和2号生理小种,对检测甘蓝植株是否感染枯萎菌及甘蓝种植区土壤是否受到枯萎菌的污染有实用价值。     

大豆疫霉根腐病菌生理小种鉴定及毒性分析

对采自黑龙江省、吉林省的42株大豆疫霉根腐病茵进行生理小种鉴定，其中11株可被分别鉴定为1号、3号和8号生理小种。1号小种为优势小种，3号、8号小种为国内首次报道。其余31株在鉴别寄主上出现中间类型反应无法鉴定小种，但可以划分为12个毒性类型，病原茵群体具有很高的毒性多态性，其中有些菌株毒性较强。     

东北春麦区小麦白粉病菌生理小种鉴定及毒性基因分析

对1999～2002年小麦白粉病菌的生理小种类型、毒性基因频率进行了研究。结果表明，白粉病菌小种种群结构复杂，1999～2002年共鉴定出33个生理小种，优势小种均为15号生理小种，出现频率分别为40．48％、22．22％、29．03％、30．30％，其次为11号和5号小种。毒性基因V3e、V3f、V5、V8的毒力频率较高，在50％以上，而V2、v4a、V4b、V12、V16、V19的毒力频率较低，低于20％。供试的小麦白粉病菌菌株含3～7个毒性基因的较多，其中含4个毒性基因组合的比例最高。为25．84％。     

寄主对马铃薯晚疫病菌群体结构的影响研究

对云南省13个寄主品种的马铃薯晚疫病菌群体结构进行研究。结果表明,云南省马铃薯晚疫病菌群体结构复杂,病菌复杂基因型群体增多,生理小种和交配型都趋于复杂化;A1交配型仍然是云南省马铃薯晚疫病菌的主要类型。鉴定生理小种的186个菌株中,共鉴定出100个生理小种类型,优势小种为1.2.3.4.5.6.7.8.9.10.11,占22.1%。品种F44-2、F45-1、PB36、昆引18、F18-1、昆引10和F29-2上都存在优势小种1.2.3.4.5.6.7.8.9.10.11,在各品种中分别占42.1%、31.6%、25.0%、21.1%、61.5%、27.3%和20.0%。滇薯6号、大理7号和克97G10-4的小种类型各不相同,甚至同一品种同一植株上分离菌的小种类型也不相同。在交配型测定过程中,还发现品种F29-2上有2个A2交配型菌株,占这个品种的25.0%,占所测定菌株的1.9%,其小种类型分别为1.2.3.5.6.7.8.9.10.11和2.3.4.6.7.9.10。     

云南、贵州玉米大斑病菌生理小种分化研究

玉米大斑病是云南和贵州省玉米生产的重要病害之一。本文对2008年和2009年在云南、贵州采集分离获得的45份大斑病病菌菌株进行了生理小种鉴定,结果在云南共鉴定出12、13、3N、123、12N、13N、23N、123N等8个生理小种,其中123N小种出现频率最高,为30%;在贵州共鉴定出123、13N、23N、123N等4个生理小种,其中123N小种是主要小种类群,占53.3%。云南的大斑病菌菌株对Ht〖STBX〗1〖STBZ〗、Ht2、Ht〖STBX〗3〖STBZ〗和HtN基因的毒性频率分别为73.3%、73.3%、90%和80%,而贵州的菌株则分别为80%、80%、100%和93.3%。两省菌株的毒性随着抗性基因组合的复杂性增加而下降,对4基因组合的毒性频率分别为30%和53.3%;贵州的菌株毒性较云南菌株为高。云南的小种构成较复杂,而贵州小种的毒性更强。     

东北春玉米区大斑病菌生理小种鉴定

对2005年采自东北玉米主产区的大斑病叶标样进行分离,经单孢纯化后获得56个菌株。通过Ht单基因鉴别寄主接种鉴定,结果表明:东北地区玉米大斑病菌生理分化已呈现复杂化,0号生理小种和1号生理小种分别占35.7%和17.9%,为优势小种,其次为123号生理小种,占12.5%,另外还存在2、3、23、123N、12和23N号生理小种。     

Temporal Variation in Setosphaeria turcica Between 1974 and 1994 and Origin of Races 1, 23, and 23N in the United States

ABSTRACT Setosphaeria turcica causes northern leaf blight, an economically important disease of maize throughout the world. Survey collections of S. turcica isolates from 1974 to 1994 provided a unique opportunity to examine temporal diversity in the eastern United States. Two hundred forty-two isolates of S. turcica from maize were studied with random amplified polymorphic DNA (RAPD) markers, mating type, and virulence on maize differential inbred lines with known Ht resistance genes to examine changes over time. One hundred forty-nine RAPD haplotypes were identified. Nearly 20% of haplotypes recurred in more than one year. Race 0 isolates declined in frequency from 83% in 1974 to near 50% in the 1990s, most likely in response to the widespread deployment of Ht1 in commercial maize hybrids. Races 23 and 23N were present in the collection at low levels throughout the study period and were also found among isolates from Virginia in 1957. The frequency of MAT1-2 isolates increased sharply after 1979 and was associated with the emergence of race 1 during the same period. RAPD markers were used to investigate the genetic diversity among a subset of isolates collected in the United States from 1976 to 1982, the period in which this dramatic shift in race frequency occurred. Multilocus haplotypes were not exclusively associated with known races of S. turcica. Based on shared haplotypes and cluster analysis, race 1 isolates share greater similarity with race 0 than with 23 or 23N isolates, indicating race 1 probably evolved from multiple lineages of race 0. Sorghum spp.-infecting isolates share greater similarity with one another than with maize-infecting isolates and represent a distinct subgroup.     

Pathogenic and genetic variability among Colletotrichum lindemuthianum isolates of different geographic origins

The pathogenic and genetic diversity of Colletotrichum lindemuthianum isolates collected from a total of 10 Central and South American, European and African countries were characterized using common bean differential cultivar pathogenicity tests and amplified fragment length polymorphism (AFLP) analysis. On the basis of pathogenicity tests, 74 isolates were attributed to 30 different pathogenic races using the CIAT-defined binary race-classification system. Twenty-one races were restricted geographically, being exclusive to different countries. Race 9 was the most widespread, being detected in four different countries. Cluster analysis of consensus AFLP data generated using three selective AFLP primer combinations grouped 86 isolates (including the 74 subjected to pathogenicity tests) into three clusters (with one isolate as an outlier). This analysis showed that the majority of South and Central American isolates were divided among two clusters, and that the limited number of European and African isolates used in this study were genetically most similar to Central American isolates. Overall, the results of this research showed some associations between the genetic diversity of the isolates and their country of origin, but not between genetic diversity and race classification of isolates.     

Genetic variation among asexual progeny of Phytophthora infestans detected with RAPD and AFLP markers

Genotypic variation among 32 single-zoospore isolates (SZI) of Phytophthora infestans , derived asexually from two hyphal-tip parental isolates (PI-105 and PI-1) of the US-8 genotype, was assessed with 80 random amplified polymorphic DNA (RAPD) primers and 18 amplified fragment length polymorphic DNA (AFLP) primer pairs. In previous investigations, the SZIs from parental isolate PI-105 showed high levels of virulence variability and were differentiated into 14 races, whereas the SZIs from PI-1 showed identical virulence to the parent. The purpose of this investigation was to determine if phenotypic variation observed among SZIs of P. infestans could be detected at the DNA level in these isolates. Polymorphism was detected with 51 RAPD primers and with all 18 AFLP primer pairs in PI-105 SZIs. In SZIs from PI-1, polymorphism was also detected with 25 RAPD primers and 17 AFLP primer pairs. Cluster analysis using the unweighted pair-group method with arithmetic averages (UPGMA) separated the SZIs from parent PI-105 into six virulence groups, 11 RAPD groups and three AFLP groups. Cluster analysis of PI-1 SZIs, which all belong to the same virulence group, differentiated them into four RAPD groups and six AFLP groups. No close correlation among RAPD, AFLP and virulence groups could be established within the two progenies of SZIs. Results of this study suggest that there is a considerable level of inherent genetic variability among SZIs derived asexually from the same parental isolate. The possible mechanisms and implications of this genetic variation are discussed.     

福建省辣椒疫霉菌群体结构表型特征分析

为了明确福建省辣椒疫霉菌群体遗传结构的表型特征,对分离自福建省15个市(县)的300株辣椒疫霉菌的交配型、甲霜灵敏感性及生理小种进行了测定。结果显示,288株为A2交配型,12株为A1交配型,出现频率分别为96%和4%,以A2占优势,在各采集点均有分布。263株对甲霜灵表现敏感,28株为中间型,9株为抗性,分别占总体的87.67%、9.33%和3.00%,甲霜灵敏感菌株为主要菌系。根据菌株对辣椒疫霉菌生理小种鉴别寄主的致病性测定结果,可将辣椒疫霉菌划分为3个生理小种,其中168株为小种3,126株为小种2,6株为小种1,分别占56%、42%和2%,小种3为福建辣椒疫霉菌优势小种。     

Pathogenicity,vegetative compatibility and amplified fragment length polymorphism (AFLP) analysis of <Emphasis Type="Italic">Fusarium oxysporum</Emphasis> f. sp. <Emphasis Type="Italic">radicis-cucumerinum</Emphasis> isolates from Turkish greenhouses

The objective of the current study was to characterize Fusarium oxysporum f. sp. radicis-cucumerinum isolates from cucumbers in Turkey in terms of pathogenicity, vegetative compatibility and amplified fragment length polymorphism (AFLP) variation. In the 2007 and 2008 greenhouse cucumber-growing seasons, surveys were conducted in Adana, Antalya, Hatay and Mersin provinces of the Mediterranean region of Turkey. Forty-seven fungal isolates of F. oxysporum were recovered from diseased cucumber plants. The pathogenicity of each isolate was tested on cucumber seedlings at the one-true-leaf stage. Forty of the 47 isolates of F. oxysporum were virulent on cucumber seedlings. Based on disease symptoms, the differential effect of temperatures of 17°C and 29°C on disease development, and the virulence on cucumber seedlings, these 40 isolates were identified as F. oxysporum f. sp. radicis-cucumerinum. Nitrate non-utilizing mutants were generated on minimal medium containing 1.5% KClO₃ and their phenotypes were determined. Mutants in different phenotypic classes were paired on minimal medium; of 40 F. oxysporum f. sp. radicis-cucumerinum isolates, thirty-eight were placed into VCG 0260. Remaining two strains were assigned to VCG 0261. The AFLP primers produced a total of 180 fragments between 200 and 500 bp in length for the 30 isolates tested. At a genetic similarity of 0.71, the UPGMA analysis separated the isolates into two distinct clusters. The first cluster, AFLP I, included 28 isolates, of which all belonged to VCG 0260. Two strains in the second AFLP cluster both belonged to VCG 0261.     

Comparison of genetic diversity and pathogenicity of fusarium head blight pathogens from China and Europe by SSCP and seedling assays on wheat

The genetic diversity and pathogenicity of isolates of Fusarium graminearum and F. asiaticum isolated from wheat heads in China were examined and compared with those of isolates of F. graminearum , F. asiaticum and F. meridionale from Europe, USA and Nepal. Genetic diversity was assessed by SSCP (single strand conformation polymorphism) and AFLP (amplified fragment length polymorphism) analysis and by molecular chemotyping. SSCP analysis of the Fg16F/Fg16R PCR amplicon differentiated F. graminearum , F. asiaticum and F. meridionale and revealed three haplotypes among sequence-characterized amplified region (SCAR) type 1 F. graminearum isolates. AFLP analysis showed a high level of genetic diversity and clustered the majority of Chinese isolates in one group along with other isolates of Asian origin. The second cluster contained F. graminearum isolates from China, Europe and the USA. Of the Chinese isolates, 79% were F. asiaticum and 81% of these were of the 3-AcDON chemotype, with only 9·5% of either chemotype 15-AcDON or NIV. All the Chinese and USA isolates of F. graminearum were 15-AcDON, whereas among the isolates from Europe, 21% were NIV and 8% were 3-AcDON chemotype. No evidence was found for possible differences in aggressiveness between F. graminearum and F. asiaticum . Highly aggressive isolates were present in each region and no evidence was found for any association between aggressiveness and geographical origin or chemotype among the isolates examined. No difference was observed in pathogenicity towards wheat seedlings between Chinese isolates and those from Europe, the USA or Nepal.     

特异性抑制剂三环唑对玉米大斑病菌致病力的影响

为明确DHN黑色素合成抑制剂三环唑对玉米大斑病菌Setosphaeria turcica致病力的影响,通过含毒介质系统研究了三环唑作用下玉米大斑病菌的黑色素生物合成量、附着胞的细胞孔径、膨压和病菌的致病力。结果显示,当三环唑浓度≤5μg/mL时,玉米大斑病菌菌落生长量和产孢量变化不显著,但黑色素的生成量降至对照菌株的43%;三环唑处理的病菌附着胞细胞壁孔径增大至2.7～3.3 nm,膨压降至3.75 MPa,侵染率下降37.5%,同时病斑面积显著减小。表明三环唑通过抑制玉米大斑病菌DHN黑色素合成,降低了病菌附着胞的膨压,从而导致致病力下降。     

Variation for pathogenicity on tomato among parasexual recombinants of Verticillium dahliae

Ten haploid prototrophic recombinant isolates (HPRs) were obtained from each of 15 parasexual crosses between complementary autotrophs derived from nine tomato isolates and one eggplant isolate of V. dahliae , including those identified as race 1 and race 2. These HPRs were tested for pathogenicity to the tomato cultivar Roma which is susceptible to both races. HPRs from a 'selfed' race 2 × race 2 cross were as pathogenic as the wild-type parent. The pathogenicity of HPRs derived from all other crosses was variable, and generally lower than the parental mean. A particularly marked reduction in pathogenicity, compared with the parental mean, was observed for HPRs recovered from two crosses between isolates belonging to different heterokaryon compatibility groups. The results suggest that pathogenicity to cv. Roma is controlled by complex interactions between genes at numerous loci.