Ma Yuxin, Yang Xuewei, Xie Meihua, Zhang Guosheng, Yang Le, Bai Na, Zhao Yining, Li Dongni, Zhang Ke-Qin, Yang Jinkui
State Key Laboratory for Conservation and Utilization of Bio-Resources & Key Laboratory for Microbial Resources of the Ministry of Education, School of Life Sciences, Yunnan University, Kunming 650091, PR China.
State Key Laboratory for Conservation and Utilization of Bio-Resources & Key Laboratory for Microbial Resources of the Ministry of Education, School of Life Sciences, Yunnan University, Kunming 650091, PR China.
Fungal Genet Biol. 2020 May;138:103352. doi: 10.1016/j.fgb.2020.103352. Epub 2020 Feb 19.
Small GTPases of the ADP-ribosylation factor (Arf) family and their activating proteins (Arf-GAPs) regulate mycelial development and pathogenicity in yeast and filamentous fungi; however, little is known about their roles in nematode-trapping (NT) fungi. In this study, an ortholog of Arf-GAP Glo3 (AoGlo3) in Saccharomyces cerevisiae was characterized in the NT fungus Arthrobotrys oligospora. Deletion of the Aoglo3 gene resulted in growth defects and an increase in hyphal septum. Meanwhile, the sporulation capacity of the ΔAoglo3 mutant was decreased by 98%, and 67.1-71.2% spores became gourd or claviform in shape (from obovoid), which was accompanied by a significant decrease in the spore germination rate. This reduced sporulation capacity correlated with the transcriptional repression of several sporulation-related genes including fluG, rodA, abaA, medA, and lreA. The ΔAoglo3 mutant was also sensitive to several chemical stressors such as Congo red, NaCl, and sorbitol. Additionally, AoGlo3 was found to be involved in endocytosis, and more myelin figures were observed in the ΔAoglo3 mutant than in the wild-type strain, which was consistent with the presence of more autophagosomes observed in the mutant. Importantly, AoGlo3 affected the production of mycelial traps and serine proteases for nematode predation. In summary, AoGlo3 is involved in the regulation of multiple cellular processes such as mycelial growth, conidiation, environmental adaption, endocytosis, and pathogenicity in A. oligospora.
ADP核糖基化因子（Arf）家族的小GTP酶及其激活蛋白（Arf-GAPs）调节酵母和丝状真菌中的菌丝体发育和致病性；然而，它们在捕食线虫（NT）真菌中的作用却鲜为人知。在本研究中，对酿酒酵母中Arf-GAP Glo3的直系同源物（AoGlo3）在NT真菌少孢节丛孢菌中进行了表征。Aoglo3基因的缺失导致生长缺陷和菌丝隔膜增加。同时，ΔAoglo3突变体的产孢能力下降了98%，67.1-71.2%的孢子形状变为葫芦形或棒状（从倒卵形），同时孢子萌发率显著降低。这种产孢能力的降低与包括fluG、rodA、abaA、medA和lreA在内的几个产孢相关基因的转录抑制有关。ΔAoglo3突变体对刚果红、NaCl和山梨醇等几种化学应激源也敏感。此外，发现AoGlo3参与内吞作用，并且在ΔAoglo3突变体中观察到的髓鞘样结构比野生型菌株中更多，这与在突变体中观察到更多自噬体一致。重要的是，AoGlo3影响用于捕食线虫的菌丝陷阱和丝氨酸蛋白酶的产生。总之，AoGlo3参与了少孢节丛孢菌中多个细胞过程的调节，如菌丝生长、分生孢子形成、环境适应、内吞作用和致病性。
