A Patched-Like Protein PsPTL Is Not Essential for the Growth and Response to Various Stresses in Phytophthora sojae

Patched (Ptc) and Patched-related (Ptr) proteins containing sterol-sensing domains (SSD) and Patched domains are highly conserved in eukaryotes for lipid transport and metabolism. Four proteins containing predicted SSD and Patched domains were simultaneously found by searching thePhytophthora sojaegenome database, and one of them was identified as a Patched-like (PTL) protein. Here, we investigated the biological function ofPsPTL. The expression level ofPsPTLwas higher during mycelial and sporulation stages, compared to zoospore (ZO), cyst, and germinated-cyst stages, without significant change during infection. However, deletion ofPsPTLusing CRISPR/Cas9 had no significant effect on the growth, development, or virulence ofP. sojae. Further investigations showed thatPsPTLis not essential forP. sojaeto cope with external stresses such as temperature, pH, oxidative and osmotic pressure. In addition, this gene did not appear to play an essential role inP. sojae’s response to exogenous sterols. The transcript levels of the other three proteins containing predicted SSD and Patched domains were also not significantly upregulated inPsPTLdeletion transformants. Our studies demonstrated that PsPTL is not an essential protein forP. sojaeunder the tested conditions, and more in-depth research is required for revealing the potential functions ofPsPTLunder special conditions or in other signaling pathways.