Characterization of Phytophthora capsici causing foliar and pod blight of snap bean in Michigan
Characterization of Phytophthora capsici causing foliar and pod blight of snap bean in Michigan
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DOI：
10.1094/pdis-92-2-0201
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发表时间：
2008-02-01
期刊：
影响因子：
4.5
通讯作者：
Hausbeck, M. K.
中科院分区：
文献类型：
--
作者：
Gevens, A. J.;Donahoo, R. S.;Hausbeck, M. K.
2003年至2005年期间，在密歇根州三个县的四个商业领域观察到绿色和黄色油豆角植物的水浸叶病变，茎坏死，豆荚枯萎病和整体植物衰退。近年来，所有田地都种植了表现出辣椒疫霉感染症状的葫芦。从菜豆茎、叶柄、叶片和豆荚中共获得680个辣椒疫霉分离物;从根部未回收到病原体。科赫的假设完成了代表性的分离物，确认P辣椒作为致病微生物。选择的分离物对黄瓜果实也是致病的，引起与辣椒疫霉感染一致的症状。所收集的辣椒疫霉分离物中的大多数对杀菌剂精甲霜灵敏感，且为A1交配型。在实验室条件下，6个来自油豆角的辣椒疫霉分离物（2003）对包括大豆在内的12个不同的商业豆类品种具有致病性。受感染的菜豆植株表现出浸水损伤、叶片坏死和萎蔫。我们对2003年和2004年收集的13 1株辣椒疫霉进行了扩增片段长度多态性分析，以调查菌株和地理种群之间的多样性，并确定是否豆辣椒疫霉菌株与葫芦科植物宿主的菌株相似。这是第一次深入研究P辣椒在密歇根州的豆角。虽然大豆品种以前被认为是一个合适的轮换作物敏感的辣椒P，这不再是一个推荐的做法。
Green and yellow snap bean plants with water-soaked foliar lesions, stem necrosis, pod blight, and overall plant decline were observed in four commercial fields in three Michigan counties during 2003 to 2005. All fields were cropped to cucurbits that exhibited symptoms of Phytophthora capsici infection in recent years. In all, 680 isolates of P. capsici were obtained from bean steins, petioles, leaves, and pods; the pathogen was not recovered from roots. Koch's postulates were completed with representative isolates, confirming P capsici as the causal organism. Select isolates also were pathogenic on cucumber fruit, causing symptoms consistent with P. capsici infection. The majority of the P. capsici isolates collected were sensitive to the fungicide mefenoxam and were of the A1 mating type. Under laboratory conditions, six P. capsici isolates from snap bean (2003) were pathogenic on 12 different commercial bean cultivars, including soybean. Infected bean plants exhibited water-soaked lesions, foliar necrosis, and wilting. We subjected 13 1 isolates collected from 2003 and 2004 to amplified fragment length polymorphism analysis to investigate diversity among isolates and geographical populations and to determine whether bean P. capsici isolates were similar to isolates from a cucurbit host. This is the first in-depth study of P capsici on snap bean in Michigan. Although bean cultivars previously were considered a suitable rotation for crops susceptible to P capsici, this is no longer a recommended practice.