胶孢炭疽菌致病相关基因Plv2功能分析

胶孢炭疽菌(Colletotrichum gloeosporioides)引起的橡胶树炭疽病是橡胶树三大叶部病害之一,严重威胁着橡胶树的生长。本研究从构建的胶孢炭疽菌RC178 T-DNA突变体库中筛选获得一株致病力明显减弱的突变菌株T1103,其T-DNA为单拷贝。采用TAIL-PCR克隆了该突变体T-DNA插入位点的侧翼序列,通过比对胶孢炭疽菌全基因组序列,发现该TDNA插入位点所在的序列包含一个5 400 bp的基因,将其命名为Plv2。Plv2基因包含3个外显子,编码一个假定的甾醇C-24甲基转移酶。敲除野生型菌株RC178中的Plv2,发现敲除突变体与T1103的致病力表现基本一致,由此推测Plv2基因为致病相关基因。

Functional analysis of the pathogenicity-related gene Plv2 in Colletotrichum gloeosporioides

Anthracnose leaf spot, caused by the fungal pathogen Colletotrichum gloeosporioides, is one of the three leaves devastating diseases that greatly affects rubber tree plantation. A mutant strain T1103 with significantly weakened virulence to rubber trees, was obtained by screening a mutant library constructed by Agrobacterium-mediated transformation (ATMT) of C. gloeosporioides RC178. This mutant contains only one T-DNA copy. The T-DNA flanking sequence of T1103 was obtained by TAIL-PCR and compared with the whole genome of the wild-type strain RC178 of C. gloeosporioides by sequence alignment. The results showed that the sequence in which the T-DNA was inserted contains a gene that was designated as Plv2. Plv2 is 5 400 bp in length, and includes 3 exons, encoding a putative C-24 sterol methyltransferase. The Plv2 gene in the wild-type strain RC178 was knocked out, and the pathogenicity test of the knock-out mutants was then performed. The results showed that the pathogenicity of all the Plv2 knock-out mutants to rubber trees was similar to that of the mutant T1103, suggesting that Plv2 is a pathogenicity associated gene in C. gloeosporioides.