An FYVE-Domain-Containing Protein, PsFP1, Is Involved in Vegetative Growth, Oxidative Stress Response and Virulence of .

Proteins that contain the FYVE zinc-finger domain are recruited to PtdIns3P-containing membranes, participating in numerous biological processes such as membrane trafficking, cytoskeletal regulation, and receptor signaling. However, the genome-wide distribution, evolution, and biological functions of FYVE-containing proteins are rarely reported for oomycetes. By genome mining of , two proteins (PsFP1 and PsFP2) with a combination of the FYVE domain and the PX domain (a major phosphoinositide binding module) were found. To clarify the functions of PsFP1 and PsFP2, the CRISPR/Cas9-mediated gene replacement system was used to knock out the two genes respectively. Only heterozygous deletion mutants of were recovered, and the expression level of in the heterozygous knockout transformants was significantly down-regulated. These mutants showed a decrease in mycelial growth and pathogenicity and were more sensitive to hydrogen peroxide. These phenotypes were recovered to the level of wild-type by overexpression gene in the PsFP1 heterozygous knockout transformant. In contrast, deletion of had no significant effect on vegetative growth, asexual and sexual reproduction, pathogenicity, or oxidative stress sensitivity. PsFP1 was primarily localized in vesicle-like structures and both the FYVE and PX domains are important for its localization. Overall, our results indicate that plays an important role in the vegetative growth and virulence of .