我国不同产区桃褐腐病病原鉴定与分析

Identification and analysis of the peach brown rot pathogens from different peach-growing areas in China

摘要:

【背景】桃褐腐病是桃树的一种重要病害，给桃果生产带来了严重的经济损失。桃褐腐病病原种类较多。【目的】明确我国不同桃产区褐腐病菌的种类。【方法】采集不同产区桃褐腐病果，采用单孢分离法分离病菌，通过形态特征、分子生物学方法和接种试验对分离株进行种类鉴定和分析。【结果】从来自浙江丽水、四川成都、云南昆明、辽宁大连、河北石家庄、北京海淀、山东泰安和山东青岛等8个不同桃产区的褐腐病果上经单孢分离获得15株分离株。各分离株菌落形态略有差异，但来自云南的分离株hfyn与其他分离株明显不同。通过rDNA ITS序列和系统进化树分析，将云南分离株hfyn鉴定为云南丛梗孢(Monilia yunnanensis)，来源于其他产区的14株分离株均鉴定为果生链核盘菌(Monilinia fructicola)。采用多对特异性引物PCR扩增分析，确证了上述鉴定结果。接种试验表明，不同产区来源的桃褐腐病菌分离株在桃果上的致病力存在差异，其中来自浙江丽水、河北石家庄、山东青岛的分离株致病力较强，而来自山东泰安和云南昆明的分离株致病力相对较弱。【结论】我国桃产区褐腐病菌主要以M. fructicola为主，但不同产区来源的菌株间存在形态和致病性差异，此结果可为我国桃褐腐病的治理提供科学依据。

Abstract:

[Background] Brown rot on peach and nectarine trees caused by Monilinia spp. is an important fungal disease, and produces serious economic losses frequently in China. There may exist more than one species of peach brown rot pathogens. [Objective] To clarify the species and pathogenicity of brown rot pathogens from different peach-growing areas in China. [Methods] The pathogens were isolated from peach brown rot fruits of different peach production areas, using the method of single spore isolation. Identification and analysis of isolates were carried out by morphological characteristics, molecular biology methods, and inoculation assay. [Results] In this study 15 brown rot pathogen isolates were obtained from 8 different peach-growing areas. The morphological characteristics of the isolates were slightly different from each other, but the isolate hfyn from Yunnan Province was significantly different from the other isolates. Based on its morphology, rDNA ITS sequence and phylogenetic analysis, the isolate hfyn was identified as Monilia yunnanensis, which was a newly found brown rot pathogen, and the other 14 isolates were identified as Monilinia fructicola. PCR amplification using several pairs of specific primers confirmed the morphological and rDNA ITS identification results. Inoculation tests showed that the pathogenicities on peach fruits of 15 isolates from different peach producing areas were different. The isolates from Lishui, Zhejiang Province, Shijiazhuang, Hebei Province, and Qingdao, Shandong Province had more virulent, and the virulences of isolates from Kunming, Yunnan Province and Tai’an, Shandong Province were relatively weak. [Conclusion] The results indicated that the major pathogen of brown rot in peach-growing areas in China was Monilinia fructicola, and there were differences in morphology and pathogenicity among these isolates from different peach-growing areas. The result from the present study may provide a scientific basis for managing peach brown rot epidemics.