苹果轮纹病菌种内遗传多样性研究

 【目的】分析苹果轮纹病菌(Botryosphaeria berengeriana)的遗传多样性并确认其优势类群。【方法】对采集分离的64个菌株进行形态特征和致病性测定,对部分菌株的进行了ITS序列测序,采用ISSR分析这些菌株的遗传多样性。【结果】通过形态特征和致病性明确了所分离的64个菌株是苹果轮纹病菌。17个菌株ITS序列与贝格伦葡萄座腔菌(Botryosphaeria berengeriana de Not f. sp. piricola(Nose) Koganezawa et Sakuma)的序列一致,并且被分成两个类型H1和H2。用13条ISSR引物从64个菌株中扩增出121条条带,其中88条多态性条带,多态性比率为72%。64个菌株的遗传相似性从0.44到0.99,并且被分成2个ISSR类群,类群1包含21个菌株、类群2包含43个菌株。【结论】本研究中贝格伦葡萄座腔菌的遗传多样性与菌株的地域、症状以及分离部位没有相关性。苹果轮纹病菌被分成2个ISSR类群,类群2是优势类群。

The Intraspecific Genetic Diversity of Pathogenic Fungi of Apple Ring Rot

【Objective】The objective of the study is to analyze the genetic diversity and find the preponderant populations of Botryosphaeria berengeriana isolates, the causal agents of ring rot disease of apple.【Method】Sixty-four isolates were identified by their morphologic characteristics in culture and their pathogenicity tests. Isolates were identified by their ITS rDNA sequence. Inter-simple sequence repeat (ISSR) analysis was used to investigate the genetic diversity of its isolates.【Result】Sixty-four isolates were identified as B. berengeriana by morphologic characteristics in culture and pathogenicity tests. The data of the ITS rDNA from selected 17 isolates accord with data of B. berengerian and separated into two haplotypes H1 and H2. The 13 functional ISSR primers generated 88 polymorphic bands within a total of 121 bands and revealed 72% polymorphism and could differentiate all 64 isolates. Their genetic similarities were from 0.44 to 0.99. Two groups of 64 isolates were identified based on their ISSR. Group 1 contains 21 isolates, while group 2 consists of 43 isolates.【Conclusion】In this study, it was found that the genetic diversity of B. berengeriana isolates were not correlated to their regions , symptoms and tissues of trees. Sixty-four isolates were separated into two ISSR groups, and group 2 predominated over group 1 in orchards .