稗草叶枯病病原尖角突脐孢菌的鉴定

The identification of barnyardgrass leaf spot caused by Exserohilum monoceras

采用形态学及分子生物学的方法对采集自湖南和北京的3株尖角突脐孢菌分离物进行了鉴定。结果表明,3株分离物(KF-1、HN-14和K-12)和保存于中国农业大学已定名的尖角突脐孢菌菌株G-9和X-27之间在菌落形态、产孢量及孢子大小和分隔方面存在较大差异。其中,K-12在PDA培养基上生长缓慢、产孢量小;菌株G-9、KF-1、X-27和HN-14生长迅速,产孢丰富。对菌株进行分子鉴定结果表明,菌株间ITS区序列相似度达98%以上,聚类分析也表明,种内各菌株之间的遗传距离明显小于种间的遗传距离;基于ITS1及ITS2序列,能将尖角突脐孢菌和突脐蠕孢属中其它种分开。由此可确定分离自湖南水稻田及中国农业大学科学园温室中自然发病的稗草病样上的3株病原真菌均为尖角突脐孢菌。

Three fungal isolates, KF-1, HN-14 and K-12, from barnyardgrass leaf blight, which were collected from Hunan and Beijing, were studied morphologically and molecularly. The results showed that there were differences between the three isolates and the two Exserohilum monoceras strains G-9 and X-27 which were accurately identified and deposited in culture collections of China Agricultural University in colonial morphology, sporulation and spore morphology especially septa of spore. G-9, KF-1, X-27 and HN-14 grow quickly and produce abundant spores on PDA plate, but K-12 grows slowly and produced less spores. To further identify the relationship of 5 isolates, 5.SS-ITS sequence were compared. Results indicated that the similarity of ITS sequence of five isolates were over 98% and the phylogenetic tree based on ITS1 and ITS2 sequence also revealed that G-9, KF-1, K-12, X-27, and HN-14 were all clustered into one group and distinct from the other outgroup and suboutgroup. Based on the above data, these three isolates were proved to be E. monoceras.