Characterization of Verticillium dahliae isolates and wilt epidemics of pepper
Characterization of Verticillium dahliae isolates and wilt epidemics of pepper
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DOI：
10.1094/pdis.2003.87.7.789
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发表时间：
2003-07-01
期刊：
影响因子：
4.5
通讯作者：
Subbarao, KV
中科院分区：
文献类型：
--
作者：
Bhat, RG;Smith, RF;Subbarao, KV
描述了加州中部海岸辣椒田黄萎病的流行和与这些流行相关的大丽轮枝菌分离物的特征。在种植阿纳海姆、墨西哥辣椒、辣椒或甜椒的田地中，每个田地枯萎植物的平均发病率范围为6.3%至97.8%。一般而言，墨西哥辣椒和甜椒作物的枯萎病发病率低于其他类型的辣椒作物。田间接种密度为2.7 ~ 66.6微菌核g（-1）干土，发病率与微菌核密度呈高度相关（r = 0.81，P < 0.01）。黄萎病在大部分调查的辣椒田中呈聚集分布，但聚集程度不同。对67个大丽轮枝菌菌株进行营养体亲和性类群（VCG）鉴定，结果表明67%属于VCG 2，22%属于VCG 4，11%属于一个新类群VCG 6。以100个月生甜椒（cv. Cal Wonder）和番茄（cv. EP 7）将接种的植物播种并在温室中孵育。甜椒幼苗仅对辣椒上的大丽轮纹病菌感病，而番茄幼苗对辣椒和番茄上的病菌均感病。VCG 2、VCG 4和VCG 6菌株对甜椒和辣椒具有高致病性。15 ~ 25 ℃是大丽轮枝菌菌丝生长的最适温度。辣椒V大丽菌分离株的分子特征，使用聚合酶链反应（PCR）为基础的随机扩增多态性DNA（RAPD）技术发现这些菌株之间的微小变化，但独特的多态性带型属于VCG 6菌株观察。辣椒黄萎病是加州中部沿海地区的主要生产限制因素。更积极的菌株V大丽花可能已被选定在这个地区作为一个结果，集约种植的做法。
Epidemics of Verticillium wilt in pepper fields of the central coast of California and isolates of Verticillium dahliae associated with these epidemics were characterized. The mean incidence of wilted plants per field ranged from 6.3 to 97.8% in fields with Anaheim, jalapeno, paprika, or bell peppers. In general, incidence of wilt in jalapeno and bell pepper crops was lower than in crops of other types of pepper. Inoculum density of V. dahliae in the surveyed pepper fields ranged from 2.7 to 66.6 microsclerotia g(-1) dry soil, and the correlation between disease incidence and density of microsclerotia was high (r = 0.81, P < 0.01). Distribution of Verticillium wilt was aggregated in a majority of the pepper fields surveyed, but the degree of aggregation varied. Vegetative compatibility group (VCG) characterization of 67 isolates of V dahliae indicated that 67% belonged to VCG 2, 22% to VCG 4, and 11% to a new group, designated VCG 6. The pathogenicity of isolates of V dahliae from bell pepper and tomato plants was tested by inoculating 1-month-old bell pepper (cv. Cal Wonder) and tomato (cv. EP 7) seedlings and incubating the inoculated plants in the greenhouse. Seedlings of bell pepper were susceptible only to the isolates of V dahliae from pepper, whereas seedlings of tomato were susceptible to both pepper and tomato isolates. Pepper isolates belonging to VCG 2, VCG 4, and VCG 6 were highly pathogenic to bell pepper and chili pepper. Temperatures between 15 and 25degreesC were optimal for mycelial growth of a majority of isolates of V dahliae. Molecular characterization of pepper isolates of V dahliae using a polymerase chain reaction (PCR)-based random amplified polymorphic DNA (RAPD) technique revealed minor variation among these isolates, but unique polymorphic banding patterns were observed for isolates belonging to VCG 6. Verticillium wilt of pepper is a major production constraint in the central coast of California. More aggressive isolates of V dahliae may have been selected in this region as a result of intensive cropping practices.