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1.
 由Pseudomonas syringae pv. actinidiae (Psa)引起的猕猴桃细菌性溃疡病是为害猕猴桃的一种毁灭性病害,1996年被列为我国森林植物检疫对象。本研究对来源于我国7个受溃疡病为害最严重地区的21个Psa菌株进行重测序分析,通过主成分分析和系统发育学分析将21个菌株分为三大类群;固定系数分析结果显示所有群体的FST值均小于0.05;核苷酸多态性分析结果显示所有菌株的Θπ值仅为3.74×10-6,且各群体间的差异不明显。这些结果表明Psa在我国的遗传多样性处于低水平状态。基因流(Nm)分析结果显示不同群体之间的Nm值均大于4,表明各群体病原菌之间存在较大的基因交流;Tajima′s D中性检验结果显示所有群体的Tajima′s D值均大于0,暗示各群体都经历平衡选择;Ka/Ks分析结果显示Psa的大部分基因都受到纯化选择,仅有极少数的基因受到正选择。本研究揭示了中国7个受溃疡病危害最严重地区Psa的遗传多样性,并且获得大量基因组数据,可为病害防治、病原菌耐药性以及抗病植株的选育提供理论依据。  相似文献   

2.
由丁香假单胞菌猕猴桃致病变种Pseudomonas syringae pv. actinidiae (Psa)侵染引起的猕猴桃细菌性溃疡病(kiwifruit bacterial canker)是全球猕猴桃生产上最具毁灭性的细菌病害。为探明福建、安徽、四川和陕西4省Psa菌株的生物型和遗传多样性,用5对PCR特异性引物PsaJ-F/-R、PsaK-F/-R、Tac-F/-R、Con002-F/-R和avrRps4-F1/-R2检测Psa菌株的生物型;用4对PCR引物27F/1492R、PsaF1/PsaR2、gapA-Fps/Rps和rpoD+364s/-1222ps分别扩增16S rRNA、ITS、gapA和rpoD基因,进行多基因联合分析Psa菌株的遗传多样性。结果表明,特异性引物Tac-F/-R从47株Psa菌株中均能扩增出一条545 bp的特异条带,其他4对引物未扩增出任何条带,说明供试Psa菌株的生物型均为biovar 3。多基因联合分析表明,4省Psa存在丰富的遗传多样性,4个群体共检测出27个单倍型,单倍型多样性为0.955。安徽、福建、四川和陕西群体的单倍型数差异较大,分别为1、8、12个和12个。4个群体的多态性位点数、核苷酸多样性和平均核苷酸差异数差异极显著(P<0.01),其中福建群体的多态性最丰富,而安徽群体的多态性最低。AMOVA分析表明,3.6%的遗传变异来源于种群间,而96.4%的遗传变异来源于种群内,说明种群内变异是遗传变异的主要来源。遗传分化分析表明,安徽省Psa群体与其他3个群体间的遗传分化极高(Fst>0.175),福建、四川和陕西群体间的遗传分化水平较低(Fst<0.017)。研究结果有利于了解福建省Psa的来源,为阻断Psa的传播和猕猴桃细菌性溃疡病的长期可持续控制提供了理论参考。  相似文献   

3.
猕猴桃溃疡病菌biovar 3群体MLVA分型技术的建立与应用   总被引：1，自引：0，他引：1  
 丁香假单胞菌猕猴桃致病变种生物型3(Pseudomonas syringae pv. actinidiae biovar 3,Psa3)是猕猴桃溃疡病菌的世界流行群体,但仅在中国存在复杂的遗传多样性。开发适于Psa3群体分型的MLVA(multilocus variable-number tandem-repeat analysis)技术是探索中国Psa3起源与流行学特性的基础。本研究对7个Psa3菌株进行了全基因组测序,结合已公布的86个全基因组数据,进行比较分析发现,中国Psa3至少存在7个亚群;在各亚群间存在多态性的24个串联重复序列中,其中10个可以通过琼脂糖凝胶电泳区分开且变异指数合适,据此建立了适于Psa3的MLVA技术。采用该技术对分别来自贵州和陕西的62和9个Psa3菌株进行群体分型,分型结果与全基因组分析高度一致,证明该MLVA体系分型准确。MLVA分型结果表明:贵州主产区修文县Psa3有3个MLVA群体,其中亚群4的组内分化明显,代表最早发生的群体;而亚群 1和3的结构单一,且多在新果园发现,是新传入群体。总之,本研究建立了一套可用于Psa3群体分型的MLVA技术,将有助于解析中国各猕猴桃产区Psa3群体结构,以及探索中国Psa3的起源、传播和流行学特征。  相似文献   

4.
 丁香假单胞菌猕猴桃致病变种生物型3(Pseudomonas syringae pv. actinidiae biovar 3,Psa3)是猕猴桃溃疡病菌的世界流行群体,但仅在中国存在复杂的遗传多样性。开发适于Psa3群体分型的MLVA(multilocus variable-number tandem-repeat analysis)技术是探索中国Psa3起源与流行学特性的基础。本研究对7个Psa3菌株进行了全基因组测序,结合已公布的86个全基因组数据,进行比较分析发现,中国Psa3至少存在7个亚群;在各亚群间存在多态性的24个串联重复序列中,其中10个可以通过琼脂糖凝胶电泳区分开且变异指数合适,据此建立了适于Psa3的MLVA技术。采用该技术对分别来自贵州和陕西的62和9个Psa3菌株进行群体分型,分型结果与全基因组分析高度一致,证明该MLVA体系分型准确。MLVA分型结果表明:贵州主产区修文县Psa3有3个MLVA群体,其中亚群4的组内分化明显,代表最早发生的群体;而亚群 1和3的结构单一,且多在新果园发现,是新传入群体。总之,本研究建立了一套可用于Psa3群体分型的MLVA技术,将有助于解析中国各猕猴桃产区Psa3群体结构,以及探索中国Psa3的起源、传播和流行学特征。  相似文献   

5.
 选用16对毒性相关基因特异性引物对四川和重庆9个县(市)分离到的200个稻瘟病菌单孢菌株进行PCR扩增,并采用最长距离法进行聚类分析,结果显示各引物均能扩增出其目的条带,多态位点百分率(P)高达93.75%,扩增频率差异较大;200个菌株可归为70个不同的单元型,其中单元型SCH13为优势单元型;在0.86遗传相似水平上,200个菌株可划分为27个遗传宗谱,包括1个优势宗谱,3个亚优势宗谱,14个次要宗谱,9个小宗谱,层次丰富;在群体平均水平上,病菌群体具有丰富的遗传多样性(H=0.324 4,I=0.484 2),且群体间差异较大;9个种群在遗传距离为0.05水平上可分为4个类群,种群遗传谱系与地理区域分布呈一定相关性。同时,该地区的群体存在一定的遗传分化(HT=0.320 0),群体内多样性大于群体间多样性(Hs=0.179 6,Dst=0.140 4),总遗传变异的56.13%存在于群体内(Gst=0.438 7),群体间基因流动性较小(Nm=0.639 6)。本研究揭示了四川和重庆部分区域稻瘟病菌群体遗传结构、遗传多样性及其与地理分布之间的关系,为抗病育种和品种布局奠定了基础。  相似文献   

6.
 抗病品种和化学防治是控制植物病害最有效的两种措施,病原菌在长期选择压下可改变其群体结构,以逐步适应品种抗性和杀菌剂压力。本研究采用拌种离体叶段法对 2012年采自我国9个省(市)的129个小麦白粉病菌Blumeria graminis f. sp. tritici单孢堆分离物进行了三唑酮敏感性检测,同时采用31个已知抗病基因品种(系)对其进行苗期毒性测定,并对二者之间的相关性进行分析结果表明:129个供试菌株对三唑酮的EC50为 109.97 mg/L,平均抗药性水平达到52.62倍,变异系数为 107.2。所有供试菌株中,99.22% 的菌株产生了抗药性,其中高抗菌株占58.91%,中抗菌株占37.98%。北京菌株的抗药性水平明显高于其他8个省市。利用Popgen1.32软件对9个省(市)小麦白粉病菌群体的毒性多样性分析结果表明,四川群体毒性基因多样性水平最高,Nei基因多样性H值为0.224 1,浙江群体最低,H值为0.096 8。小麦白粉菌群体对三唑酮的敏感性和毒性的相关性分析表明,EC50或EC50变异系数与毒性多样性之间均不存在显著的相关性,但EC50与毒性基因数目之间的关系符合对数方程。此结果可为杀菌剂和抗性品种的合理利用提供依据。  相似文献   

7.
 为明确陕西省小麦白粉菌群体的毒性频率和遗传多样性,利用34个含有已知抗白粉病基因的小麦品种(系)和5对多态性ISSR分子标记,分别对2016年渭南、西安、咸阳、宝鸡、汉中和安康等6市的15个乡镇160个小麦白粉菌单孢子堆菌株进行毒性频率分析。结果显示:供试小麦白粉菌群体对Pm1、Pm2、Pm3b、Pm3c、Pm3e、Pm3f、Pm6、Pm7、Pm8、Pm19和Pm1+2+19的毒性频率在60%~100%之间,表明这些抗性基因已丧失抗性,在生产上已经丧失利用价值,对Pm4b、Pm24、Pm2+6、Pm2+Mld、Pm2+6+?、Pm4b+Mli、Pm"Era"、Pm"XBD"和Pm21的毒性频率低于20%,表明这些抗性基因抗性良好,可在生产中利用。选取其中93个单孢子堆菌株进行遗传多样性分析,结果表明白粉菌地理群体间遗传距离在0.020 4~0.103 7之间,其中宝鸡和渭南群体的遗传距离最近,汉中和咸阳群体的遗传距离最远。群体间遗传变异占总体变异的12.82%,群体内遗传变异占87.12%,表明遗传变异主要来自于群体内。Mantel Test分析表明,小麦白粉菌群体间遗传距离与地理距离相关性不大。  相似文献   

8.
 采用RAPD技术对分离自河南省各地的43株小麦黑胚病优势病原菌(Alternaria spp.)菌株进行了遗传多样性分析。17个随机引物共扩增出151条清晰的DNA条带,所扩增出的DNA条带均为多态带,说明河南省小麦黑胚病菌存在着丰富的遗传多样性。利用NTSYS软件进行了病原菌的聚类分析,结果表明,河南省小麦黑胚病菌主要有2个种,即Alternaria alternata和A. tenuissima,种间的遗传相似系数的变化幅度为0.62~0.92。来自同一个地区的小麦黑胚病菌菌株基本上聚在了一起,表现出很近的亲缘关系,来自不同地区之间的菌株也可以交叉聚类。病原菌遗传多样性分析进一步验证了形态学的鉴定结果。  相似文献   

9.
 甘薯细菌性茎腐病是由达旦提狄克氏菌(Dickeya dadantii)引起的一种检疫性病害,近年来在我国多地发生,严重威胁我国甘薯产业的发展。建立特异灵敏的检测D. dadantii的方法对于鉴定检疫病原菌、田间监测病原菌和防控病害有重要意义。本研究对Dickeya属菌株的全基因组序列进行比较基因组学分析,筛选到D. dadantii特有的标志基因,针对标志基因设计引物,其中针对编码登录号为WP_077245517未知蛋白基因的1对引物Dad1-F(5′-CATATCAACCAGACCAGCCGTT-3′)和Dad1-R(5′-CGGCCTGCTTTTAAACAACGTATTA-3′)能只从D. dadantii扩增到167 bp目的片段。由此建立了特异灵敏的常规PCR和实时荧光定量PCR检测D. dadantii的方法,为鉴定检疫甘薯茎腐病病原菌和田间监测病害提供了有效方法。  相似文献   

10.
 甘薯细菌性茎腐病是由达旦提狄克氏菌(Dickeya dadantii)引起的一种检疫性病害,近年来在我国多地发生,严重威胁我国甘薯产业的发展。建立特异灵敏的检测D. dadantii的方法对于鉴定检疫病原菌、田间监测病原菌和防控病害有重要意义。本研究对Dickeya属菌株的全基因组序列进行比较基因组学分析,筛选到D. dadantii特有的标志基因,针对标志基因设计引物,其中针对编码登录号为WP_077245517未知蛋白基因的1对引物Dad1-F(5′-CATATCAACCAGACCAGCCGTT-3′)和Dad1-R(5′-CGGCCTGCTTTTAAACAACGTATTA-3′)能只从D. dadantii扩增到167 bp目的片段。由此建立了特异灵敏的常规PCR和实时荧光定量PCR检测D. dadantii的方法,为鉴定检疫甘薯茎腐病病原菌和田间监测病害提供了有效方法。  相似文献   

11.
Bacterial canker of kiwifruit caused by Pseudomonas syringae pv. actinidiae (Psa) is a catastrophic disease that threatens the global kiwifruit industry. As yet, no cure has been developed. Planting resistant cultivars is considered as one of the most effective ways to control Psa. However, most existing cultivars lack Psa-resistance genes. Wild Actinidia resources contain rich genetic diversity and may have powerful disease-resistance genes under long-term natural selection, but lack of knowledge about the resistance to Psa for most Actinidia species results in some excellent wild resistant genotypes being underutilized. In this study, the response to Psa of 104 wild genotypes of 30 Actinidia species (including 37 taxa) was tested with an in vitro bioassay, and a considerable number of individuals from different species with tolerance or high resistance to Psa were identified. The results showed high consistency between years. This is the first large-scale evaluation of diverse Actinidia species with resistance to Psa through an in vitro bioassay. The resistant genotypes of A. chinensis identified could be used in future kiwifruit improvement programmes. The findings should help provide an understanding of the resistance to Psa.  相似文献   

12.
Pseudomonas syringae pv. actinidiae (Psa) is a causal agent of kiwifruit bacterial canker worldwide, which has affected kiwifruit vines in China since 1996 and has subsequently spread to the main cultivation areas. Based on occurrence of Psa and pseudo-absences randomly generated in China, the consensus-based modelling technique was used to estimate the spatial spread of Psa epidemics within China. Environmental variables that related to Psa development were identified, and their contributions to Psa development were evaluated. Three modelling algorithms, namely generalized boosting models (GBM), random forests (RF) and classification tree analysis (CTA) within the BIOMOD2 framework, were employed to construct the model. The ensemble models weighted by the true skill statistic (TSS) value were used to predict the current habitat suitability of Psa, and were projected using the four general circulation models (GCMs) to assess range shifts under two types of representative concentration pathways (RCP 4.5 and RCP 8.5) by 2050. The results indicated that precipitation in March and mean temperature of warmest quarter were the most important limiting factors for distribution of Psa. The predictive accuracy of the ensemble model showed acceptable predictive powers (TSS = 0.852). Under future climate conditions, substantial net loss of suitability for Psa was estimated to be 3.03–12.5% under RCP 4.5 (except one GCM), and 2.46–9.89% under RCP 8.5. Shrinkage of suitable habitats was detected mainly in the areas currently infected by Psa. Special attention should be given to recent infectious regions in south and southwest China, considering the locally expanding kiwifruit commercial plantations.  相似文献   

13.
ABSTRACT Pseudomonas syringae pv. actinidiae, the causal agent of canker in kiwifruit (Actinidia spp.) vines, was first detected in Japan in 1984, followed by detections in Korea and Italy in the early 1990s. Isolates causing more severe disease symptoms have recently been detected in several countries with a wide global distribution, including Italy, New Zealand, and China. In order to characterize P. syringae pv. actinidiae populations globally, a representative set of 40 isolates from New Zealand, Italy, Japan, South Korea, Australia, and Chile were selected for extensive genetic analysis. Multilocus sequence analysis (MLSA) of housekeeping, type III effector and phytotoxin genes was used to elucidate the phylogenetic relationships between P. syringae pv. actinidiae isolates worldwide. Four additional isolates, including one from China, for which shotgun sequence of the whole genome was available, were included in phylogenetic analyses. It is shown that at least four P. syringae pv. actinidiae MLSA groups are present globally, and that marker sets with differing evolutionary trajectories (conserved housekeeping and rapidly evolving effector genes) readily differentiate all four groups. The MLSA group designated here as Psa3 is the strain causing secondary symptoms such as formation of cankers, production of exudates, and cane and shoot dieback on some kiwifruit orchards in Italy and New Zealand. It is shown that isolates from Chile also belong to this MLSA group. MLSA group Psa4, detected in isolates collected in New Zealand and Australia, has not been previously described. P. syringae pv. actinidiae has an extensive global distribution yet the isolates causing widespread losses to the kiwifruit industry can all be traced to a single MLSA group, Psa3.  相似文献   

14.
Pseudomonas syringae pv. actinidiae (Psa) is responsible for bacterial canker of kiwifruit. Biovar 3 of Psa (Psa3) has been causing widespread damage to yellow‐ and green‐fleshed kiwifruit (Actinidia spp.) cultivars in all the major kiwifruit‐producing countries in the world. In some areas, including New Zealand, P. syringae pv. actinidifoliorum (Pfm), another bacterial pathogen of kiwifruit, was initially classified as a low virulence biovar of Psa. Ability to rapidly distinguish between these pathovars is vital to the management of bacterial canker. Whole genome sequencing (WGS) data were used to develop PCR assays to specifically detect Psa3 and Pfm from field‐collected material without the need to culture bacteria. Genomic data from 36 strains of Psa, Pfm or related isolates enabled identification of areas of genomic variation suitable for primer design. The developed assays were tested on 147 non‐target bacterial species including strains likely to be found in kiwifruit orchards. A number of assays did not proceed because although they were able to discriminate between the different Psa biovars and Pfm, they also produced amplicons from other unrelated bacteria. This could have resulted in false positives from environmental samples, and demonstrates the care that is required when applying assays devised for pure cultures to field‐collected samples. The strategy described here for developing assays for distinguishing strains of closely related pathogens could be applied to other diseases with characteristics similar to Psa.  相似文献   

15.
Since 2008, Pseudomonas syringae pv. actinidiae virulent strains (Psa‐V) have quickly spread across the main areas of kiwifruit (Actinidia deliciosa and A. chinensis) cultivation causing sudden and re‐emerging outbreaks of bacterial canker to both species. The disease caused by Psa‐V strains is considered worldwide as pandemic. Recently, P. syringae strains (ex Psa‐LV, now called PsD) phylogenetically related to Psa‐V have been isolated from kiwifruit, but cause only minor damage (i.e. leaf spot) to the host. The different biological significance of these bacterial populations affecting kiwifruit highlights the importance of having a diagnostic method able to detect Psa‐V, which is currently solely responsible for the severe damage to the kiwifruit industry. In order to improve the specific molecular detection of Psa‐V, a real‐time PCR assay has been developed based on EvaGreen chemistry, together with a novel qualitative PCR (PCR‐C). Both methods are based on specific primer sets for the hrpW gene of Psa. The real‐time PCR and PCR‐C were highly specific, detecting down to 50 and 200 fg, respectively, and were applied to a range of organs/tissues of kiwifruit with and without symptoms. These methods are important tools for both sanitary and certification programmes, and will help to avoid the spread of Psa‐V and to check possible inoculum sources. In addition to being used as routine tests, they will also enable the study of the biology of Psa‐V and the disease that it causes, whilst avoiding the detection of other populations of related P. syringae present in kiwifruit.  相似文献   

16.
 为了明确我国落选短体线虫群体的遗传多样性,利用mtCOI基因标记对落选短体线虫9个地理群体的遗传结构及遗传分化进行分析。结果显示,9个地理群体中共得到101条mtCOI序列,发现28个碱基变异位点,形成14个单倍型。其中,H1单倍型最常见,为7个地理群体的59个个体共有,推测其可能为祖先单倍型。全部地理群体在物种水平呈现中等遗传多样性(HT = 0.706±0.131),聚类分析显示其可分为类群Ⅰ与类群Ⅱ两个类群,AMOVA分析揭示落选短体线虫整体水平的遗传分化主要来源于种群间。Mantel检验表明落选短体线虫群体的遗传距离与地理距离存在正相关性,但是不同种群之间的遗传分化程度与地理距离没有显著关系。中性检验和错配分布检验均揭示落选短体线虫在整体水平和两个类群上的群体历史动态都处于相对稳定的状态。  相似文献   

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