云南蓝莓枝干溃疡病病原菌鉴定及rDNA-ITS序列分析

Identification and the Internal Transcribed Spacer Regions Analysis of the Pathogen Causing Stem Canker on Blueberry in Yunnan

自2010年云南省昆明市周边及丽江市蓝莓商业化种植区发生了一种蓝莓新病害,典型症状为茎干和枝条枯萎死亡,发病早期部分枝条和叶片枯萎但不脱落,韧皮或木质部横切面呈轻棕黄色或灰黑色变色.采用温室接种致病性测定、形态及分子鉴定等方法对蓝莓枝干溃疡病病原进行研究.结果表明：从各种植区采集病样15份,分离获得来自蓝莓病株茎干、枝等器官的15个生长较一致的真菌分离物;致病性试验证实,均为蓝莓枝干溃疡病病原菌;经形态学鉴定为Botryosphaeria dothidea,利用ITSI-5.8S-ITS4进行PCR扩增,并将测序结果在GenBank中进行同源性比对分析显示,其序列分析结果与B.dothidea的同源性为99％ ～100％,分子鉴定与形态学鉴定结果一致.该病原菌在蓝莓果树上的危害在云南省内尚属首次报道.

The identification of the pathogens isolated from the stem blight on Highbush Blueberries （ Vaccinium corymbosum L. ） was carried out. Fifteen of diseased samples were collected and observed in Kunming and Lijiang in Yunnan Province （south-western China）. Typical symptoms of the disease were blight and dieback on the stems with lesions extending along entire branches. All of isolates were isolated from stem and twigs of infected blueberry plants. Based on the pathogenicity testing, the re-suhs proved that LIJIANG09 were the pathogens of highbush Blueberries dieback disease. The morpho- logical identification showed that LIJIANG09 was identified as Botryosphaeria dothidea. Further, mor- phological identification result was confirmed by analyzing the rDNA internal transcribed spacer region （ITSI-5.8S-ITS4）. BLAST searches at GenBank showed a high identity with B. dothidea reference se- quences （ITS： 〉 99% ）. Representative sequences of isolates from both regions were deposited in GenBank （ ITS ： Accession No. JX096631 ）. Morphological and molecular identification confirmed this fungal pathogen as B. dothidea. B. dothidea was first reported as the pathogen of Highbush Blueberries stem blight disease in Yunnan.