鸡蛋花鞘锈菌重寄生真菌的种类鉴定及其寄主范围测定

Species Identification and Host Range Determination of a Hyperparasitic Fungus on Coleosporium plumeriae

关键词:  鸡蛋花锈病  鸡蛋花鞘锈菌  重寄生真菌  Simplicillium subtropicum  寄主范围

Key words:  plumeria rust  Coleosporium plumeriae  hyperparasitic fungus  Simplicillium subtropicum  host range

摘要:

鉴定鸡蛋花鞘锈菌Coleosporium plumeriae重寄生真菌的种类,明确其寄主范围,为鸡蛋花锈病及其他植物锈病的生物防治提供依据。通过分离和纯化鸡蛋花锈病叶背夏孢子堆上的重寄生真菌,经单孢纯化获得12个单孢菌株,其菌落及分生孢子特征一致,菌落白色,分生孢子近圆形或卵圆形,单胞,无色,呈头状聚生在分生孢子梗顶端。选取菌株PR-CPH1作为代表,分析3个片段的核苷酸序列,PR-CPH1的ITS（MW505984）、SSU（MW505988）和LSU（MW505987）序列与Simplicillium subtropicum的ITS（AB603990）、SSU（LC496895）和LSU（LC496880）序列的一致性分别为99.00%、98.11%和98.11%。系统发育树分析发现,菌株PR-CPH1的ITS-SSU-LSU联合序列与S.subtropicum(菌株号:JCM18180)聚在同一个分支。结合形态特征和ITS、SSU、LSU的序列分析,鉴定鸡蛋花鞘锈菌重寄生真菌为S.subtropicum。测定S.subtropicum寄主范围的结果显示,在8种植物锈菌中,菌株PR-CPH1可重寄生鸡矢藤鞘锈菌C.paederiae、香茶菜鞘锈菌C.plectranthi和落叶松-杨栅锈菌Melampsora larici-populina。S.subtropicum为4种锈菌的重寄生真菌为首次报道。

Abstract:

The species and host range of a hyperparasitic fungus on Coleosporium plumeriae were identified to provide the basis for the biological control of plumeria rust and other plant rust diseases.The hyperparasitic fungus was isolated and purified from the uredinia of C.plumeriae on the reverse leaf of plumeria rust,12 single-spore strains were obtained by single-spore purification.The characteristics of colonies and conidia of 12 single-spore strains were consistent.The colony was white,and the conidia were nearly round or oval,unicellular,and colorless,and aggregated at the apex of the conidiophore.Strain PR-CPH1 was selected as the representative to analyze the nucleotide sequences of the three fragments.The consistency of the ITS (MW505984),SSU (MW505988) and LSU(MW505987) sequences of PR-CPH1 with the ITS (AB603990),SSU (LC496895) and LSU (LC496880) sequences of Simplicillium subtropicum was 99.00%,98.11% and 98.11%,respectively.Phylogenetic tree analysis showed that the ITS-SSU-LSU joint sequence of strain PR-CPH1 and S.subtropicum (strain number:JCM18180) clustered in the same branch.Combined with morphological characteristics and sequence analysis of ITS,SSU and LSU, the hyperparasitic fungus of C.plumeriae was identified as S.subtropicum. The host range of S.subtropicum was determined,and the results showed that the strain PR-CPH1 could reparasitize C.paederiae,C.plectranthi and Melampsora larici-populina among the eight plant rust fungi.This is the first report that S.subtropicum is the hyperparasitic fungus of 4 plant rust fungi.