台湾引进甜杨桃的两种真菌病原鉴定

Identification of Two Fungal Pathogens in Sweet Carambola from Taiwan

对福建闽南地区种植的从台湾引进的甜杨桃进行真菌性病害的鉴定。在病害症状和病症组织病理学鉴定的基础上,进行菌株的rDNA-ITS区序列PCR扩增,测序结果在GenBank中进行同源性搜索,下载部分具有代表性属或种的ITS序列,利用软件MEGA4构建分子系统发育树;按照柯赫氏法则对病原物进行了致病性测定,回接后的叶片或果实上产生与田间自然侵染相同的症状,重新分离到相同病原物。通过病原形态、rDNA-ITS序列及致病性分析,确定发生在叶片与果实上的2种主要真菌性病原,分别是引起叶斑病的拟茎点霉(Phomopsis sp.)和果实、叶片炭疽病的胶孢炭疽菌(Colletotrichum gloeosporioides)。

Fungal diseases of the sweet carambola, Averrhoa carambola L., introduced from Taiwan were investigated. The infected samples were collected from southern Fujian. Two fungal pathogens were identified by using histopathology and the ribosomal DNA internal transcribed spacer （ITS） sequencing. By comparing with the corresponding sequences in GenBank, the phylogenetie trees for the strains, SC 01 and SC-06, were constructed. The two isolates were re-inoculated by the Koch＇s rule to the leaves and fruits to produce identical symptoms as observed in the field. Subsequently, it was confirmed that the leaf spot was caused by Phomopsis sp. , and the leaf and fruits anthracnose by Collotrichura gloeosporioides.