云南、广西三七黑斑病病原链格孢菌的鉴定

正黑斑病是三七栽培生产中常见的一大病害,叶片受害产生近圆形或不规则水浸状病斑,常导致成株落叶、幼苗生长点及茎秆顶端腐烂枯死。其病原一般认为是链格孢属真菌人参链格Alternaria panax Whetzel~(1,2]),也有相关研究证明黑斑病病原为细链格孢Alternaria tenuis Nees~(3]),后定名为链格孢Alternaria alternata Keissl~(4])。本研究利用ITS序列和histone 3部分编码序列的PCR鉴定,结合形态学鉴定,分析三七主产区黑斑病菌的组成和分布情况及几种病原菌的致病力差异,以期为三七黑斑病防治提供理论依据。

Identification of Alternaria species associated with black spot disease on Panax notoginseng in Yunnan and Guangxi

Black spot disease caused by Alternaria species is an important and common disease on Panax notoginseng. In this study, 82 isolates were obtained from diseased P. notoginseng plants sampled from Yunnan and Guangxi provinces. ITS region and partial coding sequence of histone 3 gene of all isolates were amplified and sequenced to do the phylogenetic analysis. Based on molecular identification and morphological traits, the isolates were identified as Alternaria tenuissima, A. alternata and A. panax separately. This study firstly confirmed that A. tenuissima was the dominant pathogen population (62 isolates, 75.6%) associated with black spot disease in main producing areas of P. notoginseng, followed by A. alternata (12 isolates, 14.6%) and A. panax (8 isolates, 9.8%). Among these species, A. panax had the highest pathogenicity to P. notoginseng.