蛋白激酶FgBud32参与禾谷镰刀菌的生长发育、致病和胁迫应答

由禾谷镰刀菌引起的小麦赤霉病是一种毁灭性的小麦真菌病害,在世界范围内造成小麦产量和质量的巨大损失。实验室前期在禾谷镰刀菌中共鉴定到116个蛋白激酶,其中FgBUD32基因的缺失会造成营养生长和有性生殖方面的严重缺陷,但其在禾谷镰刀菌中的详细功能尚未报道。本研究通过系统比较Fgbud32突变体与野生型PH-1及互补菌株的表型差异,对FgBud32在禾谷镰刀菌中的生物学功能进行了解析。研究结果显示Fgbud32突变体在多个表型方面存在缺陷,与野生型菌株以及互补菌株相比,其生长速率急剧下降,菌丝弯曲且分支减少;分生孢子的产量显著降低,形态变短,隔膜减少,萌发率降低且萌发速率延迟;在有性生殖时期不能产生子囊壳或子囊壳前体;对小麦穗和胚芽鞘的致病力以及DON毒素的合成能力均显著下降。进一步胁迫试验表明,FgBUD32基因的缺失导致禾谷镰刀菌对氧化胁迫(H₂O₂)以及DNA损伤胁迫(羟基脲和甲磺甲酯)的敏感性增加。此外,我们还发现FgBud32在细胞核和细胞质中均有定位,且在一定时期或条件下会从细胞质向细胞核内聚集。综上所述,FgBUD32基因参与了禾谷镰刀菌的营养生长、极性生长、无性/有性生殖、DON毒素合成、致病以及对氧化胁迫和DNA损伤胁迫的应答等多种生命活动,但其具体的作用机制还有待深入研究。

Protein kinase FgBud32 is involved in fungal development,pathogenicity and stress responses in Fusarium graminearum

Fusarium head blight (FHB) caused by Fusarium graminearum is a highly destructive disease of wheat, causing major reductions in yield and quality worldwide. Our laboratory identified 116 protein kinases in F. graminearum in previous study, among which deletion of FgBUD32 gene could cause serious defects in vegetative growth and sexual reproduction, while detailed function of the gene in F. graminearum has not been reported. In this study, the biological functions of FgBud32 were revealed by systematically comparing the phenotypic difference among the wild-type PH-1, Fgbud32 mutant and complemented transformant. It was found that Fgbud32 mutant was defective in vegetative growth, polarized growth, conidiogenesis, conidial germination and sexual reproduction. The Fgbud32 mutant also failed to form any perithecia. In addition, the Fgbud32 mutant exhibited a significant reduction in DON biosynthesis and pathogenicity toward wheat heads and coleoptiles. Moreover, deletion of FgBUD32 gene increased the sensitivity of F. graminearum to oxidative stress (H₂O₂) and DNA damage stresses (HU and MMS). The FgBud32 was localized in both cytoplasm and nucleus, and accumulated in nucleus under certain stages or conditions. Taken together, the protein kinase FgBud32 was involved in vegetative growth, polarized growth, asexual/sexual reproduction, DON biosynthesis, infection, and responses to oxidative and DNA damage stresses of F. graminearum. Its underlying mechanism needs to be investigated.