柿果黑腐病发病情况调查及病原菌的分离鉴定

Incidence Survey and Pathogen Identification of Black Rot Tissues in Persimmons

2010年8月—2012年10月对上海市售的产自广西桂林、江苏东台、广东、山西和浙江杭州的柿子进行调查,发现所有产地的柿子均存在"果肉颗粒状黑腐"或"果顶黑腐"的症状。运用扫描电镜观察,可见果肉黑腐颗粒严重木栓化,部分颗粒有大量菌丝,果顶黑腐组织中均含有大量菌丝。对病害组织进行病原菌的分离,结果显示各个批次柿子果肉中的黑腐颗粒均可分离出枝孢属真菌,检出率达41.27%,应是引起果肉颗粒状黑腐病的重要原因之一。依据柯赫氏法则对果顶黑腐组织中分离到的真菌进行有伤接种鉴定致病性,得到一株致病性最强的病原真菌,应用形态学和真菌rDNA ITS序列分析及多聚半乳糖醛酸酶基因序列分析,确定其为细极链格孢菌(Alternaria tenuissima),为引起柿子果顶黑腐病的重要原因。

Our survey of persimmon fruits marketed in Shanghai during August 2010 to October 2012 showed that all persimmons except those from Shanxi province had either ＂black rot granules in f lesh＂ or ＂black rot at the top of fruit＂. Suberization in black rot granules and mycelium in black rot tissues at the top of the flesh or in some black rot granules were observed by scanning electron microscope. Cladosporium spp. were isolated from the black rot granules in all batches of persimmons with a detection rate of up to 41.27%, which confirm ed that Clad osporium spp. may be one of the causes of black rot granules in persimmons. The m ost pa thogenic fungus was o btained by wounding and inoculation with the fungi isolated from black rot tissues at the top of persimmon flesh according to Koch’s Rule and identified as Al ternaria tenuissima by morphological characterization, rDNA ITS analysis and endopolygalacturonase gene analysis. Taken together, our results provide a useful reference for making countermeasures against this disease.