AUTHOR=Cai Yunfei , Chen Xue , Li Peixuan , Ren Weiheng , Zhang Qiang , Wang Yiwen , Jiang Yina , Zhu Pinkuan , Toyoda Hideyoshi , Xu Ling 

TITLE=Phosphorylation status of a conserved residue in the adenylate cyclase of Botrytis cinerea is involved in regulating photomorphogenesis, circadian rhythm, and pathogenicity

JOURNAL=Frontiers in Microbiology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1112584

DOI=10.3389/fmicb.2023.1112584

ISSN=1664-302X

ABSTRACT=<p>Adenylate cyclase (AC) regulates growth, reproduction, and pathogenicity in many fungi by synthesizing cyclic adenosine monophosphate (cAMP) and activating downstream protein kinase A (PKA). <italic>Botrytis cinerea</italic> is a typical necrotrophic plant-pathogenic fungus. It shows a typical photomorphogenic phenotype of conidiation under light and sclerotia formation under dark; both are important reproduction structures for the dispersal and stress resistance of the fungus. The report of <italic>B. cinerea</italic> adenylate cyclase (BAC) mutation showed it affects the production of conidia and sclerotia. However, the regulatory mechanisms of the cAMP signaling pathways in photomorphogenesis have not been clarified. In this study, the S1407 site was proven to be an important conserved residue in the PP2C domain which poses a remarkable impact on the phosphorylation levels and enzyme activity of the BAC and the overall phosphorylation status of total proteins. The point mutation <italic>bac<sup>S1407P</sup></italic>, complementation <italic>bac<sup>P1407S</sup></italic>, phosphomimetic mutation <italic>bac<sup>S1407D</sup></italic>, and phosphodeficient mutation <italic>bac<sup>S1407A</sup></italic> strains were used for comparison with the light receptor white-collar mutant Δ<italic>bcwcl1</italic> to elucidate the relationship between the cAMP signaling pathway and the light response. The comparison of photomorphogenesis and pathogenicity phenotype, evaluation of circadian clock components, and expression analysis of light response transcription factor genes <italic>Bcltf1</italic>, <italic>Bcltf2</italic>, and <italic>Bcltf3</italic> showed that the cAMP signaling pathway could stabilize the circadian rhythm that is associated with pathogenicity, conidiation, and sclerotium production. Collectively, this reveals that the conserved S1407 residue of BAC is a vital phosphorylation site to regulate the cAMP signaling pathway and affects the photomorphogenesis, circadian rhythm, and pathogenicity of <italic>B. cinerea</italic>.</p>