AUTHOR=Zhou Duanxu , Xie Meihua , Bai Na , Yang Le , Zhang Ke-Qin , Yang Jinkui 

TITLE=The Autophagy-Related Gene Aolatg4 Regulates Hyphal Growth, Sporulation, Autophagosome Formation, and Pathogenicity in Arthrobotrys oligospora

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.592524

DOI=10.3389/fmicb.2020.592524

ISSN=1664-302X

ABSTRACT=<p>Autophagy plays an important role in cell growth and development. The autophagy-related gene <italic>atg4</italic> encodes a cysteine protease, which can cleave the carboxyl terminus of Atg8, thus plays a role in autophagosome formation in yeast and filamentous fungi. <italic>Arthrobotrys oligospora</italic> is well known for producing special trapping-devices (traps) and capturing nematodes. In this study, two Δ<italic>Aolatg4</italic> mutants were generated using targeted gene replacement and were used to investigate the biological functions of autophagy in <italic>A. oligospora</italic>. Autophagic process was observed using the AoAtg8-GFP fusion protein. The mutants showed a defective in hyphal growth and sporulation and were sensitive to chemical stressors, including menadione and Congo red. The spore yield of the <italic>ΔAolatg4</italic> mutants was decreased by 88.5% compared to the wild type (WT), and the transcript levels of six sporulation-related genes, such as <italic>abaA</italic>, <italic>fluG</italic>, <italic>brlA</italic>, and <italic>wetA</italic>, were significantly downregulated during the conidiation stage. Deletion of <italic>Aolatg4</italic> also affected the cell nuclei and mycelial septal development in <italic>A. oligospora</italic>. Importantly, autophagosome formation and the autophagic process were impaired in the Δ<italic>Aolatg4</italic> mutant. Moreover, the Δ<italic>Aolatg4</italic> mutant lost its ability to form mature traps. Our results provide novel insights into the roles of autophagy in <italic>A. oligospora</italic>.</p>