Abstract: Strain AAE is a pathogenic fungus isolated from infected barnyardgrass(Echinochloae sp.) samples.Crude protein of AAE could induce the resistance of rice seedlings against Magnaporthe grisea by significantly alleviating the occurrence of rice blast and the blast severity was reduced by 23.55%.The internal transcribed space(ITS) sequence of the AAE was amplified by PCR and subsequently sequenced.BLAST search of this conserved sequence in GenBank indicated that AAE belongs to Alternaria genus,and the accession number of GenBank is EF192234.The ITS-based phylogenetic tree was also constructed.Strain AAE and Alternaria alternate were on the same clade,sharing 99.2% homology.By combining morphological characteristics with phylogenetic analysis,AAE was identified as Alternaria alternata.

Key words: Alternaria alternate, induced resistance, Magnaporthe grisea, internal transcribed space, phylogenetic analysis

摘要： 从感病稗草标样上分离到一株病原真菌AAE，其粗蛋白预处理的水稻幼苗接种稻瘟病菌后，稻瘟病的发病显著减轻，诱抗效果达23.55%。用PCR技术扩增了该菌的内转录间隔区基因序列，并进行了测序，GenBank登录号为EF192234。BLAST同源检索结果显示与该序列高度同源的均为链格孢属的内转录间隔区基因序列。选取同源性高的菌株的内转录间隔区基因序列进行系统发育分析，发现菌株AAE与Alternaria alternata处于同一分枝，相似性为99.2%，结合形态特征将它鉴定为Alternaria alternata。

关键词: 链格孢菌, 诱导抗性, 稻瘟病菌, 内转录间隔区, 系统发育分析