罗伯茨绿僵菌中嘧啶前体合成酶基因MrThi12的功能研究

Functional analysis of MrThi12, a pyrimidine precursor biosynthesis enzyme gene in Metarhizium robertsii

通过同源基因比对,在罗伯茨绿僵菌中找到了单拷贝的嘧啶前体合成酶基因MAA_02402,命名为Mr Thi12。该基因Mr Thi12全长1 234bp,c DNA序列全长1 029bp,编码342个氨基酸。构建同源重组载体,利用农杆菌介导的方法进行基因敲除。突变菌株在维生素B1缺乏的培养基上,生长很慢,菌丝形态异常,多分叉,完全不能产生气生菌丝和分生孢子。但是一旦有外源维生素B1时,生长状态能完全恢复,对家蚕的致死能力没有变化。

Metarhizium robertsii, a filamentous ascomycete fungus, is well known as the causative agent of insect green muscardine disease. By homologous genes blast, a single copy of pyrimidine precursor biosynthesis enzyme gene MAA_02402, named Mr Thi12, was found in the genome of M. robertsii. The Mr Thi12 c DNA has a full length of 1 029 bp, which encodes a protein of 342 amino acid residues. This study aimed at characterizing the function of Mr Thi12 gene by knocking it out using the method of target gene replacement. The ΔMrthi12 mutant strain grew very slowly, and could not produce aerial hyphae andconidia in the vitamin B1-lacking media. However, when vitamin B1 was added in the medium, the phenotype of the ΔMrthi12 mutant strain could be fully recovered, without significant difference with the wild type strain.