禾谷炭疽菌转录因子CgrStuA调控营养生长、孢子产生、萌发及附着枝形成

A transcription factor CgrStuA regulates vegetative growth, conidial production, germination, and hyphopodium formation of Colletotrichum graminicola

摘要:

【背景】禾谷炭疽菌[Colletotrichum graminicola (Ces.) G.W. Wilson]是一种重要的植物病原真菌，可导致玉米炭疽病的发生。APSES (Asm-1、Phd1、Sok2、Efg1和StuA)型转录因子StuA是真菌特有的螺旋-环-螺旋(helix-loop-helix)转录因子，参与调控真菌的营养生长、孢子产量、萌发和致病性等。【目的】在禾谷炭疽菌中鉴定一个APSES型转录因子CgrStuA，明确其在禾谷炭疽菌生长和发育中的作用。【方法】利用同源重组的原理构建禾谷炭疽菌CgrstuA基因敲除突变菌株，并对突变体进行表型分析，包括营养生长、孢子产量、孢子萌发及致病力等。【结果】CgrstuA编码一个含有707个氨基酸的蛋白，含有一个KilA-N结构域。CgrstuA缺失突变体表现为营养生长减缓，两种类型的孢子产量降低，卵圆形孢子的萌发率极低，附着枝的数量明显增加，但致病性与野生型相比无显著差异。【结论】CgrStuA在禾谷炭疽菌的营养生长、孢子产量、萌发及附着枝的形成调控中发挥重要作用，但不影响致病性。

Abstract:

[Background] Colletotrichum graminicola (Ces.) G.W. Wilson is a major pathogenic fungus infecting plants, causing maize anthracnose. The APSES (Asm-1, Phd1, Sok2, Efg1 and StuA) transcription factor StuA, a fungal specific helix-loop-helix transcription factor, regulates the vegetative growth, conidial yield, germination, and pathogenicity of fungi. [Objective] To reveal the role of an APSES transcription factor CgrStuA identified in C.graminicola in the growth and development of C.graminicola. [Methods] The CgrstuA-deleted mutants were constructed by homologous recombination, and the obtained mutants were characterized in terms of the vegetative growth, conidial yield, germination, and pathogenicity. [Results] CgrstuA encoded a protein composed of 707 residues and containing a KilA-N domain. The CgrstuA-deleted mutants exhibited slow vegetative growth, decreased yields of two types of conidia, an extremely low germination rate of oval conidia, and significantly increased hyphopodia. However, there was no significant difference in the pathogenicity between the wild type and the mutants. [Conclusion] CgrStuA play important roles in the regulation of vegetative growth, conidial yield, germination, and hyphopodium formation of C.graminicola, while it did not affect the pathogenicity.