The La-related protein PsLARP4_5 is crucial for zoospore production and pathogenicity in Phytophthora sojae

Abstract

AbstractA large number of La-related proteins (LARPs), most of which share a La-motif and one or more adjacent RNA-recognition (RRM) domains, are known to play a function in diverse processes. Among the LAPRs, LARP4 and LARP5 have been mainly reported to act as positive translation factors. In Phytophthora sojae, only one protein with typical LARP protein features was identified, and it was named LARP4_5 due to the presence of an RRM_LARP4_5-like domain. The PsLARP4_5 gene was significantly upregulated in zoospores and during the infection stage. By comparing the biological characteristics of a wild-type strain with three PsLARP4_5 knockout transformants, it was found that PsLARP4_5 was involved in mycelial growth, sporangium and zoospore production, and pathogenicity of P. sojae. Further analysis of the transcriptome indicated that many differentially expressed genes could participate in several essential biological processes in the PsLARP4_5 transformant, including translation, as structural constituents of ribosomes or cytosolic large ribosomal subunits and others. Notably, 76 genes with a role in the ribosome pathway were downregulated in the PsLARP4_5 transformant, suggesting that PsLARP4_5 might affect translation. Overall, these findings indicate that PsLARP4_5 plays an essential role in the development and pathogenicity of P. sojae.