Anastomosis Group Determination of Rhizoctonia solani Kühn (Telemorph: Thanatephorus cucumeris) Isolates from Tomatoes Grown in Aydin,Turkey and their Disease Reaction on Various Tomato Cultivars

In the Province of Aydin‐Turkey most frequently Fusarium spp. and secondly Rhizoctonia solani Kühn were isolated from the roots and crown of tomato plants. Based on affinities for hyphal fusion with test isolates, all R. solani isolates were identified as AG‐4. The tomato cultivars which were grown in soil infested with R. solani AG‐4 exhibited different reactions. From the point of symptom expression and the rate of seedling emergence Sunny 6066 F1 was found to be the most resistant cultivar, whereas Rio Grande, Rio Fuego, NDM 725, Interpeel and Konia were the most susceptible cultivars.     

醋栗番茄Solanum pimpinellifolium遗传多样性分析

野生种醋栗番茄包含丰富的变异,具有众多优良性状。本研究对从世界不同地区收集的433份醋栗番茄遗传资源进行了表型鉴定及遗传多样性分析。表型鉴定结果表明,在收集的433份醋栗番茄中约有14%为樱桃番茄,370份典型醋栗番茄中约22%的材料存在不同程度的分离。群体变异分析表明,不同性状间变异系数存在较大差异,其中柱头变异系数最大,为56.716%;花瓣数遗传稳定,变异系数最小,为2.082%;相关分析表明,多个性状间存在显著相关性;利用表型和基因型数据聚类均将醋栗番茄群体划分为两大类群;主成分分析表明,坐果率、单果重、可溶性固形物对变异的贡献率较大。研究结果将为利用醋栗番茄进行栽培种番茄遗传改良奠定一定的基础。     

山东省玉米纹枯菌融合群类型及遗传多样性

从山东省14个县市区采集的玉米纹枯病标本上分离获得103个玉米纹枯菌菌株。核荧光染色确定菌丝细胞核的数目,以及利用配对培养法确定不同菌株细胞是否融合。结果表明这些菌株分别属于多核丝核菌的AG-1-IA、AG-1-IB、AG-1-IC、AG-3、AG-4-HG-I、AG-5和WAG-Z融合群和双核丝核菌的AG-Ba融合群,其中AG-1-IA类型菌株数量占菌株总数的60.19%,为优势融合群。通过inter-simple sequence repeats（ISSR）标记技术进行菌株的遗传多样性分析,获得45个ISSR分子标记,其中91.1%的片段具有多态性,表明种群间存在丰富的遗传多样性。UPGMA聚类分析将103个菌株分成6个遗传聚类群,遗传聚类群的菌株组成说明遗传群组的划分与菌株的地理来源和菌株融合群类型均存在一定的相关性。     

中国北方马铃薯黑痣病立枯丝核菌的融合群鉴定

从山东、甘肃、青海、内蒙古、河北和黑龙江6省采集马铃薯黑痣病标本300余份,分离获得251个立枯丝核菌Rhizoctonia solani菌株。融合群测定结果表明,这些菌株分别属于多核的丝核菌AG‐3、AG1‐IB、AG4‐HG‐Ⅰ、AG4‐HG‐Ⅱ、AG4‐HG‐Ⅲ、AG‐5和AG‐11融合群。其中AG‐3是优势致病群,占分离菌株总数的71.31%;其次是AG4‐HG‐Ⅰ,占15.14%;AG‐11融合群菌株是国内首次从罹病马铃薯植株上分离得到。从各融合群中选取代表性的菌株进行5.8S rDNA‐ITS区序列分析,结果表明,隶属不同融合群或亚群菌株的5.8S rDNA‐ITS区序列存在较大的差异,而相同融合群(亚群)不同菌株的序列具有较高一致性。     

一个新的番茄黄绿叶突变体表型鉴定与遗传分析

植物黄绿叶突变体不但在植物的光合作用、叶绿素的合成代谢途径、叶绿体的遗传分化与发育等一系列基础研究中具有重要作用,而且还可以作为标记性状应用到育种研究上。本研究以前期化学诱变得到的一个番茄黄绿叶突变体为材料,对其主要表型与光合作用特征特性进行鉴定分析,发现突变体从第1片真叶开始变黄,植株矮小,叶片叶绿素含量和净光合速率相对野生型极显著降低,叶绿体类囊体片层结构畸形。突变体和野生型进行正反交,分析其遗传方式。发现其F2群体正常叶与黄绿叶的分离比为3∶1,表明黄绿叶是由单个基因突变引起的隐性性状。本研究为后期的基因定位研究奠定了基础。     

Occurrence of Six Begomoviruses Infecting Tomato Fields in Venezuela and Genetic Characterization of Potato Yellow Mosaic Virus Isolates

Begomoviruses are one of the major pathogens in tomato crops worldwide. In Venezuela, six begomovirus species have been described infecting tomato: Potato yellow mosaic virus (PYMV), Euphorbia mosaic Venezuela virus (EuMVV), Merremia mosaic virus (MeMV), Tomato chlorotic leaf distortion virus (ToCLDV), Tomato yellow margin leaf curl virus (TYMLCV) and Tomato yellow leaf curl virus (TYLCV). In this study, the occurrence of these viruses was analysed by PCR in 338 tomato plants exhibiting virus‐like symptoms. Sixty‐three per cent of the plants were positive at least to one of the begomoviruses tested. PYMV and TYLCV were the most frequent viruses showing 39.6 and 23.7% occurrence, respectively. Phylogenetic analyses revealed two groups of PYMV isolates from several Caribbean Basin countries. The first group clustered isolates from several countries, including Venezuela, and the second group clustered only Colombian isolates. Due to the high prevalence of PYMV and TYLCV in Venezuela, it is suggested that the surveillance and control strategies currently applied in the country should be focused on these two begomoviruses.     

中国东北地区玉米纹枯病菌的融合群鉴定

自东北三省采集玉米纹枯病标本300余份,分离获得286个丝核菌菌株。融合群测定及5.8S rDNA-ITS区序列分析结果表明,这些菌株分别属于多核丝核菌的AG1-IA、AG1-IB、AG1-IC、AG4-HG-I、AG4-HG-III、AG-5、WAG-Z群及双核丝核菌的AG-Ba群。其中AG1-IA是优势致病群,占分离菌株总数的38.46%,其次是WAG-Z和AG-5群,分别占26.92%及24.83%。AG4-HG-III群菌株是国内首次从罹病玉米植株上分离得到。自各融合群中选取代表性的菌株进行5.8     

黄淮海地区夏玉米纹枯病菌的融合群鉴定

One hundred and seventy-six isolates were obtained from corn sheath blight samples in Huanghuai Plain and Haihe Plain (including Shandong, Henan, Hebei Provinces and Northern regions of Jiangsu Province) of China. Anastomosis group identification and 5.8S rDNA-internal transcribed spacer (ITS) sequence analysis showed that the isolates belonged to multinucleate Rhizoctonia AG1-IA, AG1-IB, AG4-HG-I, AG-5 and WAG-Z and binucleate Rhizoctonia AG-A and AG-Ba. Of these, AG-1-IA was the major anastomosis group(AG)（64.20% of total isolates), followed by AG-Ba (12.50%), WAG-Z (10.23%), AG1-IB (5.11%), AG4-HG-I (3.98%), AG-5 (2.27%) and AG-A (1.70%). AG-Ba was isolated for the first time from maize in China. 5.8S rDNA-ITS sequence analysis showed that the isolates could be distinctly separated based on their AG types. The isolates belonging to the same AG (or sub-AG) showed 97%-100% sequence identity.     

黄淮海地区夏玉米纹枯病菌的融合群鉴定

从黄淮海地区采集玉米纹枯病标样250余份,分离得到176个丝核菌菌株。融合群测定及5.8SrDNA-ITS区序列分析结果表明,这些菌株分别属于多核丝核菌的AG1-IA、AG1-IB、AG4-HG-I、AG-5、WAG-Z融合群及双核丝核菌的AG-A、AG-Ba融合群。其中AG1-IA是优势融合群,占分离菌株总数的64.20%,其次是AG-Ba,占12.50%,再依次分别是WAG-Z(10.23%)、AGI-IB(5.11%)、AG-4-HG-I(3.98%)、AG-5(2.27%)和AG-A(1.70%)。其中AG-Ba融合群是国内首次在玉米上分离得到。从各融合群中选取代表性的菌株进行5.8S rDNA-ITS区序列分析结果表明,隶属不同融合群或亚群的菌株其5.8S rDNA-ITS区序列存在较大的差异,而相同融合群(或亚群)不同菌株之间其序列的一致性可高达97%-100%。     

中国北方棉花主产区立枯丝核菌的融合群鉴定

从山东、河北、河南三省采集棉花立枯病样品和土壤200余份,经分离获得198个丝核菌Rhizoctonia solani分离物。菌丝融合测定及5.8S rDNA-ITS区序列分析结果表明,这些分离物分别属于多核丝核菌的AG4-HG-I和AG4-HG-III融合群以及双核丝核菌的AG-A、AG-F、AG-Fb融合群。其中AG4-HG-I是优势融合类群,占分离物总数的88.38%,其次是AG4-HG-III,占10.10%,AG-A、AG-F、AG-Fb各仅有1株。其中双核丝核菌AG-A、AG-F和AG-Fb融     

广东省水稻纹枯病菌遗传多样性与致病力分化的研究

利用随机引物扩增多态性DNA（PAPD）分子标记技术分析了来自广东省7个县市48个水稻纹枯病菌菌株的遗传多样性,以筛选出的10个随机引物对菌株进行PAPD－PCR扩增,共产生了98个PAPD分子标记,其中89．9％的片段具有多态性。48菌株间的遗传相似性系数（以Nei基因一致度表示）在0．56－0．949之间,用UPGMA和类分析可将它们分为5个RAPD遗传聚类群（A、B、C、D、E）,相同地区来源的菌株基本上聚类在同一组群内。在温室中对供试菌株进行致病性测定,结果表明所有菌株对水稻品种Tetep都有致病性,菌株间致病力差异显著（α＝0．05）,病情指数范围为0．73－18．7,平均感指病指数为5．24。试验分析结果表明水稻纹枯病菌具有丰富的遗传多样性,不同县市的菌株存在很大的遗传分化现象（FST＝0．579）,RAPD遗传聚类群的划分与菌株的地理来源有明显的相关性,但菌株的致病力差异与菌株的来源、遗传聚类组群的划分没有明显的相关性。     

Genetic and Phenotypic Diversity among Botrytis cinerea Isolates in Iran

Forty-four Botrytis cinerea isolates from different hosts and geographical regions were studied for colony morphology, mycelial growth rate at different temperatures, pathogenicity and molecular diversity. Botrytis cinerea isolates had temperature optima of 20–25°C and isolates showed variation in growth rate at different temperatures. Two morphological types were identified among tested isolates: mycelial and sclerotial. The pathogenicity of isolates was tested on grapevine leaves, and it was revealed that nine of 44 isolates were non-pathogenic and among them seven were of mycelial type. There was no correlation between mycelium growth rate and pathogenicity. Genetic diversity was investigated using nine arbitrary decaprimers. No relationship was found between molecular clusters and geographical region or sampling time; whereas isolates from the same plant host tended to cluster with each other. Seven of nine non-pathogenic isolates were separated from pathogenic ones.     

立枯丝核菌遗传多样性研究方法介绍

立枯丝核菌（Rhizoctonia solani Kühn）是一个集合种，遗传多样性丰富.关于遗传多样性的研究一直是R. solani研究的热点.本文就用于R. solani遗传多样性研究的方法进行了综述.分别解释并阐述了各种方法的优缺点，其中菌丝融合法是研究R. solani遗传多样性的传统方法，该法需借助显微镜且耗时耗力；同工酶法简便、高效、低廉，但常需要与其它方法联用；脂肪酸法操作难度小，价格相对较低，但该法受菌株生长状况和脂肪酸脂化方法的限制；分子标记法方法众多，各有利弊，通过比较发现rDNA-ITS是研究R. solani遗传多样性比较合适的方法.本文还介绍了不同方法在R. solani遗传多样性研究中的具体应用.     

甘薯杂交F_1群体材料的遗传多样性研究

甘薯(Ipomoea batatas(L.)Lam.)作为世界上一种重要的粮食、饲料、工业原料及新型能源作物,从有性生殖F1选择优良实生系进行选择育种一直是甘薯育种的重要方式。为了优化甘薯杂交育种方法,合理选配杂交组合,提高育种效率,本试验利用SSR标记研究了甘薯杂交群体基于SSR标记及13个农艺性状的遗传多样性,得到了群体内的聚类图,并且筛选出了甘薯的高产株系。群体SSR标记的聚类分析结果显示,群体材料与各亲本遗传距离比较远,被聚为3类,而亲本单独聚在另外一类。13个农艺性状的聚类将亲本与部分群体材料聚在了一起,且将群体材料和亲本材料作为一个整体时,其遗传距离的变异高达30%以上,远远高于SSR标记所获得的遗传变异系数。     

High levels of gene flow and heterozygote excess characterize Rhizoctonia solani AG-1 IA (Thanatephorus cucumeris) from Texas

To date, much of the genetics of the basidiomycete Thanatephorus cucumeris (anamorph = Rhizoctonia solani) remains unknown. Here, we present a population genetics study using codominant markers to augment laboratory analyses. Seven single-copy nuclear RFLP markers were used to examine 182 isolates of Rhizoctonia solani AG-1 IA collected from six commercial rice fields in Texas. Thirty-six multilocus RFLP genotypes were identified. Population subdivision analyses indicated a high degree of gene flow/migration between the six geographic populations. Tests for Hardy-Weinberg equilibrium (HWE) among the 36 multilocus RFLP genotypes revealed that four of the seven loci did not significantly differ from HWE. Subsequent analysis demonstrated that departures from HWE at the three remaining loci were due to an excess of heterozygotes. Data presented here suggest that R. solani AG-1 IA is actively outbreeding (heterothallic). Possible explanations for heterozygote excess, which was observed at all seven RFLP loci, are discussed.     

Assessment of genetic variation in tomato （Solanum lycopersicum L.） inbred lines using SSR molecular markers

A study was conducted to determine the genetic diversity of 39 determinate and indeterminate tomato inbred lines collected from China, Japan, S. Korea, and USA. Using 35 SSR polymorphic markers, a total of 150 alleles were found with moderate levels of diversity, and a high number of unique alleles existing in these tomato lines. The mean number of alleles per locus was 4.3 and the average polymorphism information content (PIC) was 0.31. Unweighted Pair Group Method with Arithmetic Mean (UPGMA) clustering at genetic similarity value of 0.85 grouped the inbred lines into four groups, where one USA cultivar formed a separate and more distant cluster. The most similar inbred lines are from USA, both with determinate type, whereas the most different lines are from USA (Us-16) and Japan (Ja-2) with determinate and indeterminate growth habit, respectively. Clustering was consistent with the known information regarding geographical location and growth habit. The genetic distance information reported in this study might be used by breeders when planning future crosses among these inbred lines.     

马铃薯实生群体遗传多样性的SSR分析

以云南马铃薯品种‘剑川红’植株1个浆果中的天然实生种子产生的70个单株以及B20[CIP010(♀)×CIP004(♂)]杂交组合后代100个实生苗单株为材料,采用12对SSR引物对自交种和杂交实生群体的遗传差异性进行分析,旨在从后代群体中找到与母本(亲本)在分子水平上表现一致的植株,为种质资源的长期保存提供依据。结果表明:(1)‘剑川红’自交群体的多态性比率为81.6%,比杂交组合B20实生群体的多态性比率72.8%略高,说明2个群体的多态性比率均较高。(2)聚类分析结果显示,自交后代和杂交后代群体的遗传相似系数均较高,变化范围均在0.74~0.96之间,说明2个群体均发生了不同程度的遗传分离,但分离的程度较小,绝大多数条带表现一致。(3)在所有供试材料中,同一浆果中均未发现与‘剑川红’母株在分子水平上表现完全一致的单株。研究认为,在分子水平上寻找完全不分离的实生群体难度非常大,需进一步评价与母株(亲本)在分子水平上相似株系的田间表现,从而确定是否可以通过相近或极相近株系来恢复种源。     

浙皖鄂地区水稻纹枯病菌5个种群的遗传结构分析

水稻纹枯病是世界性的主要病害之一。目前对该病病原菌种群的遗传多样性研究不多,知之甚少,了解其种群的遗传结构可以增加对其进化历程的了解,以制定科学的防治策略。水稻纹枯病菌通常被认为是以无性克隆繁殖为主,但有研究报道它具有混合繁殖方式。有关我国浙皖鄂地区水稻纹枯病菌种群的遗传多样性研究尚未见报道。为了解该地区水稻纹枯病菌种群的遗传变异、基因流、繁育方式及其遗传背景,采用ITS-5.8SrDNA测序技术,分析了分离自浙江富阳(FY)、安徽绩溪(JX)和巢湖(CH)以及湖北荆州(JZ)和孝感(XG)的5个水稻纹枯病菌种群75个菌株的遗传多样性。RhizoctoniasolaniAG-1IA是采集地区水稻纹枯病菌的优势类群。ITS-5.8SrDNA序列经测定共检测到78个多态位点,碱基A、T、C、G的平均含量分别为25.4%、33.6%、21.0%和20.0%。序列的平均转换与颠换比(Ti/Tv)为1.65,其中密码子第3位点的变异最高。根据序列的核苷酸变异共定义了29种单倍型,其中单倍型H5为5个种群的共享单倍型,占样本数的61.33%。5个种群的单倍型多样性和核苷酸多样性分别为0.627和0.482%,显示水稻纹枯病菌种群具有较高的遗传多样性。种群间固定化指数Fst为-0.0253-0.0170,基因流Nm为5.56-11.12,说明种群间基因交流频繁,基因流抑制了由遗传漂变引起的遗传分化,菌丝或菌核短距离扩散和带菌种子远距离传播增加了种群间的基因交流。AMOVA分析显示,种群间的遗传变异仅占总变异的19.03%,而80.97%的变异存在于种群内部,种群间的遗传分化很低。Mantel检验发现,遗传距离与地理距离无显著相关性(r=-0.241,P=0.499)。采用UPGMA法构建的单倍型间的系统发育树表明,不同地点的单倍型分支混合分布,这进一步验证了Mantel检验的结果。单倍型的网状分析显示,水稻纹枯病菌种群曾经发生过种群暴发而不断扩散,因还未能获得足够的时间建立更加复杂的结构故而呈非典型"星状"。采用中性检验分析了水稻纹枯病菌种群遗传结构,结果表明,种群间存在很强的自然选择作用,群体符合Hardy-Weinberg遗传平衡,说明水稻纹枯病菌群体是一个随机交配群体,具有以担孢子进行有性繁殖和以菌丝或菌核进行无性繁殖的混合繁殖方式。这种生物学特性可能是导致其在较小生态范围内较高的遗传多样性水平和较低的种群遗传分化的原因。另外,水稻纹枯病菌经有性繁殖产生新的基因型,并通过无性繁殖在群体内固定繁殖,这种遗传模式极有可能导致其进化潜能提高,极易对杀菌剂产生抗性。因此,对水稻纹枯病菌的防治,除了施用化学药剂和种植抗性品种外,还需要防治农田灌水引起的病原菌(菌丝和菌核)在地区间的流动传播,减少带菌种子迁移或农用机械的交叉污染,对水稻、大豆和玉米等寄主作物的种子进行播前处理等等,这些对于水稻纹枯病菌的防治也是极为重要的。     

新疆北疆棉田立枯丝核菌菌丝融合群及其营养亲和群研究

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(Rhizotonia solaniKühn)菌株,经玻片吉姆萨氏染剂(Gimsa′sstain)染色程序观察细胞核数目,全部测试菌株均属于多核。用标准菌株,通过载玻片菌丝融合实验测定,将纯化的272个菌株划归为3个菌丝融合群: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种不同配方的培养基中筛选的效果好的麦芽蛋白胨(MPDA)配方培养基(Ⅱ)进行对峙培养,以建立标准菌株,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,研究说明新疆北疆地区棉田立枯丝核菌各菌丝融合群内确有不同程度的分化。     

近缘物种的遗传多样性及其亲缘关系的取样策略研究

取样策略的问题目前大多停留于对单一物种的种质资源研究.然而,对野生近缘植物取样策略的研究,不仅有利于准确快捷地阐明物种间的系统发育关系,而且对于了解遗传多样性分布状况,制定野外考察、材料收集取样及保护策略均有重要的理论指导意义.以巴山松及其近缘种为例,利用cpSSR(叶绿体微卫星)和AFLP2种分子标记对其取样策略和统计方法进行分析,揭示居群取样个体数和基因位点数与遗传多样性的关系以及基因(引物)和系统树构建方法对亲缘关系确定的影响.研究表明:(1)居群取样个体数和基因位点数差异对遗传多样性影响并不显著,但当居群取样个体数为30个左右,单引物基因位点数为60个以上,总位点数为480个以上时,所得遗传多样性及亲缘关系较为准确可靠.(2)较多数目的基因(引物)对于得到较为准确可靠的亲缘关系分析是十分必要的.(3)系统树构建方法对近缘种亲缘关系的确定有一定的影响.