AUTHOR=Zhu Meichen , Liu Yankun , Yang Xuewei , Zhu Lirong , Shen Yanmei , Duan Shipeng , Yang Jinkui 

TITLE=p21-activated kinase is involved in the sporulation, pathogenicity, and stress response of Arthrobotrys oligospora under the indirect regulation of Rho GTPase-activating protein

JOURNAL=Frontiers in Microbiology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1235283

DOI=10.3389/fmicb.2023.1235283

ISSN=1664-302X

ABSTRACT=<p>The p21-GTPase-activated protein kinases (PAKs) participate in signal transduction downstream of Rho GTPases, which are regulated by Rho GTPase-activating proteins (Rho-GAP). Herein, we characterized two orthologous Rho-GAPs (AoRga1 and AoRga2) and two PAKs (AoPak1 and AoPak2) through bioinformatics analysis and reverse genetics in <italic>Arthrobotrys oligospora</italic>, a typical nematode-trapping (NT) fungus. The transcription analyses performed at different development stages suggested that <italic>Aopaks</italic> and <italic>Aorga1</italic> play a crucial role during sporulation and trap formation, respectively. In addition, we successfully deleted <italic>Aopak1</italic> and <italic>Aorga1</italic> via the homologous recombination method. The disruption of <italic>Aopak1</italic> and <italic>Aorga1</italic> caused a remarkable reduction in spore yield and the number of nuclei per cell, but did not affect mycelial growth. In ∆<italic>Aopak1</italic> mutants, the trap number was decreased at 48 h after the introduction of nematodes, but nematode predatory efficiency was not affected because the extracellular proteolytic activity was increased. On the contrary, the number of traps in ∆<italic>Aorga1</italic> mutants was significantly increased at 36 h and 48 h. In addition, <italic>Aopak1</italic> and <italic>Aorga1</italic> had different effects on the sensitivity to cell-wall-disturbing reagent and oxidant. A yeast two-hybrid assay revealed that AoPak1 and AoRga1 both interacted with AoRac, and AoPak1 also interacted with AoCdc42. Furthermore, the <italic>Aopaks</italic> were up-regulated in ∆<italic>Aorga1</italic> mutants, and <italic>Aorga1</italic> was down-regulated in ∆<italic>Aopak1</italic> mutants. These results reveal that AoRga1 indirectly regulated AoPAKs by regulating small GTPases.</p>