Su Xueling, Liu Hong, Xia Yuxian, Cao Yueqing
School of Life Sciences, Chongqing University, Chongqing 401331, China.
Chongqing Engineering Research Center for Fungal Insecticides, Chongqing 401331, China.
J Fungi (Basel). 2022 Jun 1;8(6):594. doi: 10.3390/jof8060594.
Conidium is the main infection unit and reproductive unit of pathogenic fungi. Exploring the mechanism of conidiation and its regulation contributes to understanding the pathogenicity of pathogenic fungi. , a transcription factor, was reported to participate in the conidiation process. However, the regulation mechanism of in conidiation is still unclear. In this study, we analyzed the function of and its regulation mechanism in conidiation through knocking out and overexpression of in entomopathogenic fungus . Results showed that the colonial growth of disruption mutant (Δ) was significantly decreased, and conidiation was earlier compared to wild type (WT), while overexpression of led to a delayed conidiation especially when carbon or nitrogen sources were insufficient. Overexpression of resulted in a conidiation pattern shift from microcycle conidiation to normal conidiation on nutrient-limited medium. These results indicated that Mavib-1 acted as a positive regulator in vegetative growth and a negative regulator in conidiation by affecting utilization of carbon and nitrogen sources in . Transcription profile analysis demonstrated that many genes related to carbon and nitrogen source metabolisms were differentially expressed in Δ and OE strains compared to WT. Moreover, affects the conidial germination, tolerance to UV-B and heat stresses, cell wall integrity, conidial surface morphology and conidial hydrophobicity in . These findings unravel the regulatory mechanism of in fungal growth and conidiation, and enrich the knowledge to conidiation pattern shift of filamentous fungi.
分生孢子是致病真菌的主要感染单位和繁殖单位。探索分生孢子形成及其调控机制有助于理解致病真菌的致病性。据报道，一种转录因子参与了分生孢子形成过程。然而，其在分生孢子形成中的调控机制仍不清楚。在本研究中，我们通过敲除和过表达昆虫病原真菌中的该基因，分析了其在分生孢子形成中的功能及其调控机制。结果表明，该基因缺失突变体（Δ）的菌落生长显著降低，与野生型（WT）相比分生孢子形成更早，而过表达该基因导致分生孢子形成延迟，尤其是在碳源或氮源不足时。在营养受限培养基上，过表达该基因导致分生孢子形成模式从微循环分生孢子形成转变为正常分生孢子形成。这些结果表明，Mavib-1通过影响该真菌中碳源和氮源的利用，在营养生长中起正调控作用，在分生孢子形成中起负调控作用。转录谱分析表明，与碳源和氮源代谢相关的许多基因在Δ和OE菌株中与WT相比存在差异表达。此外，该基因还影响该真菌的分生孢子萌发、对UV-B和热胁迫的耐受性、细胞壁完整性、分生孢子表面形态和分生孢子疏水性。这些发现揭示了该基因在真菌生长和分生孢子形成中的调控机制，并丰富了丝状真菌分生孢子形成模式转变的知识。
