AoRan1 Is Involved in Regulating Conidiation, Stress Resistance, Secondary Metabolism, and Pathogenicity in Arthrobotrys oligospora

<i>Arthrobotrys oligospora</i> is a representative nematode-trapping (NT) fungus that is able to capture, kill, and digest nematodes by producing specialized three-dimensional networks (traps) under nutrient-deprived conditions. Ran1 is a serine/threonine protein kinase that can act as a negative regulator of sexual conjugation and meiosis. However, the specific role of Ran1 remains largely unknown in NT fungi. Here, we identified AoRan1 (AOL_s00004g277) via gene disruption, phenotypic analysis, and metabolomic analysis. Our findings reveal that <i>Aoran1</i> knockout caused a remarkable increase in conidial production, traps, and nematode feeding efficiency. In addition, the absence of <i>Aoran1</i> resulted in the accumulation of lipid droplets and increased autophagic levels as well as increased tolerance to cell wall synthesis-disturbing reagents and oxidants. Metabolomic analyses also suggested that AoRan1 is involved in multiple metabolic processes, such as fatty acid biosynthesis. In summary, our results suggest that AoRan1 is crucial in conidiation, pathogenicity, and secondary metabolism. This study's results further our understanding of the molecular mechanisms by which AoRan1 regulates conidiation and trap formation in <i>A. oligospora</i>.