新疆加工型辣椒一种新的细菌性叶斑病病原的鉴定
Characterization of Pseudomonas fulva as a new pathogen of pepper leaf spot isolated from Xinjiang in China

2014-2015年在新疆沙湾县加工型辣椒Capsicum annuum L.上发现一种细菌性叶斑病。为明确其病原种类，采用组织分离法分离病原菌，依据柯赫氏法则进行致病性测定，并对菌株进行16S rDNA和持家基因rpoD及gryB的扩增、序列测定和系统发育分析，对其进行鉴定。结果表明，获得的8个细菌菌株间致病力明显差异。致病细菌与已报道的黄褐假单胞菌Pseudomonas fulva菌株的16S rDNA、rpoD基因、gryB基因的同源性分别达到了99.1%~99.9%、99.4%~99.5%和97.6%~100.0%。结合革兰氏染色反应、菌体形态、培养性状、生理生化反应、寄主范围等特征，将病原菌鉴定为黄褐假单胞菌。该病原菌通过人工接种还能侵染番茄、茄子、马铃薯、黄瓜、西瓜、甜瓜、四季豆、豆角、豇豆、白菜、萝卜、胡萝卜及芹菜等多种植物。
In 2014 and 2015, a serious bacterial disease was found on the cultivated processing pepper Capsicum annuum L. commonly in Shawan County, Xinjiang. Eight pathogenic bacteria were isolated and purified from the infected leaves of processing pepper and confirmed by using Koch's postulates to identify the pathogen. The isolates were tested morphologically, biochemically, and phylogenetically based on 16S rDNA, as well as gryB gene and rpoD gene sequences. Also, the host range was examined for this pathogenic bacterium. The results showed that the strains shared the highest similarity with Pseudomonas fulva in 16S rDNA, gryB gene and rpoD gene sequence with 99.1%-99.9%, 97.6%-100.0% and 99.4%-99.5% homology respectively. In combination with morphological, physiological and biochemical characteristics, and pathogenicity test, the causal pathogen was therefore identified as P. fulva. Artificially inoculation showed these isolates could affect many other plants, such as tomato, eggplant, potato, cucumber, water melon, melon, kidney beans, cabbage, radish, carrot, celeries, etc.