Xie Xiangyun, Wang Yulong, Jin Shaoxia, He Lili, Jia Zefeng, Huang Bo
College of Life Sciences, Liaocheng University, Liaocheng 252059, China.
Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei 230036, China.
J Invertebr Pathol. 2023 Nov;201:108009. doi: 10.1016/j.jip.2023.108009. Epub 2023 Oct 18.
As a key component of carbon source metabolism in fungi, CreC WD40 repeat protein is regulated by carbon catabolite repression (CCR). However, the understanding of the functions of CreC in entomopathogenic fungi is currently limited. Here, CreC in Metarhizium robertsii (MrCreC) was identified, and its roles in fungal development, conidiation, environmental stress response, and insecticidal virulence were explored. MrCreC is localized to cytoplasm, and MrCreC deletion affects fungal growth on various nutrients. Compared to the wild type, the sporulation of ΔMrCreC strain was significantly decreased by 60.3%. Further qPCR analysis found that deletion of MrCreC resulted in repression of sporulation-related genes such as AbaA, FlbA, Flbc, MedA, FlbD, FluG, and wetA. In addition, MrCreC loss did not alter heat stress tolerance but resulted in enhanced tolerance to UV-B. Interestingly, bioassays showed that the virulence following exposures to topical applications or injection of conidial suspensions of both infection and injection was impaired compared with that of the wild type. Further analysis showed that the adhesion and cuticle penetration genes in ΔMrCreC was down-regulated during infection, and the appressorial formation rate was significantly reduced. A deletion of MrCreC significantly also reduced immune escape and nutrient utilization genes in insect hemocoel. In conclusion, MrCreC is involved in the growth, development and virulence of M. robertsii. These findings advance our understanding of the function of CCR pathway-related genes.
作为真菌碳源代谢的关键组成部分，CreC WD40重复蛋白受碳分解代谢物阻遏（CCR）调控。然而，目前对昆虫病原真菌中CreC功能的了解有限。在此，我们鉴定了罗伯茨绿僵菌中的CreC（MrCreC），并探讨了其在真菌发育、产孢、环境应激反应和杀虫毒力中的作用。MrCreC定位于细胞质，缺失MrCreC会影响真菌在各种营养物质上的生长。与野生型相比，ΔMrCreC菌株的产孢量显著降低了60.3%。进一步的qPCR分析发现，缺失MrCreC导致AbaA、FlbA、Flbc、MedA、FlbD、FluG和wetA等产孢相关基因受到抑制。此外，缺失MrCreC不会改变热应激耐受性，但会增强对UV-B的耐受性。有趣的是，生物测定表明，与野生型相比，经局部应用或注射分生孢子悬浮液进行感染和注射后的毒力均受损。进一步分析表明，在感染过程中，ΔMrCreC中的粘附和角质层穿透基因下调，附着胞形成率显著降低。缺失MrCreC还显著降低了昆虫血腔中的免疫逃逸和营养利用基因。总之，MrCreC参与了罗伯茨绿僵菌的生长、发育和毒力。这些发现推进了我们对CCR途径相关基因功能的理解。
