中文摘要：

本研究采用引物对OPA2-1L／OPA2-1R对供试小孢子链格孢菌株OPA2-1区段进行扩增，所有菌株都可获得PCR产物。核苷酸序列分析表明：不同小孢子链格孢种OPA2-1核苷酸序列存在明显差异。利用邻近结合法构建系统发育树，供试菌株被分为8个组，梨黑斑链格孢Alternaria gaisen、长柄链格孢A．longipes、树状链格孢A．arborescens明显被归于不同分支，显示OPA2-1核苷酸序列对这些种均具有区分能力；链格孢A．alternata的一些不同分离物被聚在不同组中，说明链格孢A．alternata存在明显遗传差异，可能为一个复合体。OPA2-1核苷酸序列富于变化，可作为小孢子链格孢系统发育研究的一种有用的手段。

英文摘要：

The OPA2-1 region of small-spored Alternaria species was amplified with specific primer pairs, OPA2-1L/OPA2-1R, all strains produced one single same size band. The analysis of their nucleotide acid sequences indicates that certain differences were found in nucleotide sequences among these species. The phylogenetic tree constructed based on neighbor-joining method 6bows that these isolates were divided into eight clades. Alternaria gaisen, A. longipes and A. arborescens were clustered into different clades, while isolates ofA. alternata were distributed into different groups. It shows that A. alternata should be treated as a species complex. It is found that clear variations were present in the OPA2-1 sequences of all tested small-spored Alternaria species, it provides a meaningful information for phylogenetics of small-spored Alternaria species.