[目的]鉴定明确我国砂梨主产区白纹羽病的病原菌种类,为该病的有效防控提供理论依据.[方法]在我国砂梨主产区调查白纹羽病的发生危害特点并采集病根样品,通过组织分离法和单菌丝纯化获得分离株,对获得的菌株采用形态学和分子生物学相结合的方法进行种类鉴定和致病性验证.[结果]从湖北、福建、贵州、四川和山东等砂梨主产区采样到48份病根样品,共分离获得128个座坚壳(Rosellinia)菌株.所有菌株的菌落初期为白色,9 d后有黑色素沉淀;菌丝均无色透明,产生有分支,部分在隔膜处呈梨形膨大.36个代表菌株多基因(ITS、TUB、RPB2和LSU)系统发育分析的结果显示,所获得的座坚壳(Rosellinia)菌株均属褐座坚壳菌(R.necatrix),但不同来源菌株的基因序列有异,在系统进化树中聚集在3个不同的亚分支.从3个亚分支中选取其品种来源均为翠冠梨的3个菌株HB1-1-15、FJ1-2-2和GZ1-2-3,于小麦粒上培养14 d后拌土接种到杜梨生根试管苗后均可产生与田间相同的症状,但3个菌株的致病力存在显著差异.[结论]我国砂梨主产区白纹羽病的病原均为褐座坚壳菌(R.necatrix),不同来源菌株的基因序列之间存在明显差异.本研究是我国梨白纹羽病病原系统鉴定的首次报道.

Species of Diaporthe infect a wide range of plants and live in vivo as endophytes, saprobes or pathogens. However, those in peach plants are poorly characterized. In this study, 52 Diaporthe strains were isolated from peach branches with buds, showing constriction canker symptoms. Phylogenetic analyses were conducted using five gene regions: internal transcribed spacer of the ribosomal DNA (ITS), translation elongation factor 1-α (TEF), ß-tubulin (TUB), histone (HIS), and calmodulin (CAL). These results coupled with morphology revealed seven species of Diaporthe, including five known species (D. caryae, D. cercidis, D. eres, D. hongkongensis, and D. unshiuensis). In addition, two novel species D. jinxiu and D. zaofenghuang are introduced. Except for the previously reported D. eres, this study represents the first characterization of Diaporthe species associated with peach constriction canker in China, and contributes useful data for practicable disease management.