套袋苹果褐点病菌分类鉴定及致病性

2011和2012年山东栖霞、蓬莱、沂源等地套袋苹果果实出现了一种红褐色病斑。从病斑上分离获得两株枝顶孢属Acremonium真菌,其中一株产生头状排列的分生孢子,另一株产生链状排列的分生孢子。2个菌株都能从伤口侵染近成熟期的苹果果实,导致果肉细胞坏死,表面凹陷,形成红褐色坏死斑。2个菌株都不能侵染无伤果实。2个菌株的ITS、β-微管蛋白基因、核糖体大亚基（nucLSU）和小亚基（nucSSU）的DNA序列完全相同。依椐两个菌株的ITS和nucLSU的DNA序列和形态特征,将2个菌株鉴定为菌核生枝顶孢Acremonium sclerotigenum。A. sclerotigenum是一种机会真菌,条件适宜时可侵染套袋的苹果果实,导致褐色坏死病斑,称之为枝顶孢褐点病。

Identification and pathogenicity of brown spot pathogen of bagged apples

A new brown spot lesion on bagged apples was discovered in Penglai, Qixia and Yiyuan of Shandong Province in 2011 and 2012. Diseased apple fruits were sampled and two strains of Acremonium were isolated from the brown lesions. One of them produced conidia arranged in capitiform and the other in chains. Both strains could infect ripe apple fruits through wounds, resulting in brown sunken lesions, but could not infect unwounded fruits. ITS, β-tubulin, nucLSU and nucSSU sequences of the two strains did not show any variation. The two strains were identified as Acremonium sclerotigenum according to ITS and nucLSU sequences, and morphological character. A. sclerotigenum is an opportunistic pathogen. The pathogen would infect apple fruits before harvest when conditions were favorable. The new disease was named Acremonium brown spot.