Functional analysis of a Phytophthora host-translocated effector using the yeast model system

PeerJ. 2021 Dec 7:9:e12576. doi: 10.7717/peerj.12576. eCollection 2021.

Abstract

Background: Phytophthora plant pathogens secrete effector proteins that are translocated into host plant cells during infection and collectively contribute to pathogenicity. A subset of these host-translocated effectors can be identified by the amino acid motif RXLR (arginine, any amino acid, leucine, arginine). Bioinformatics analysis has identified hundreds of putative RXLR effector genes in Phytophthora genomes, but the specific molecular function of most remains unknown.

Methods: Here we describe initial studies to investigate the use of Saccharomyces cerevisiae as a eukaryotic model to explore the function of Phytophthora RXLR effector proteins.

Results and conclusions: Expression of individual RXLR effectors in yeast inhibited growth, consistent with perturbation of a highly conserved cellular process. Transcriptome analysis of yeast cells expressing the poorly characterized P. sojae RXLR effector Avh110 identified nearly a dozen yeast genes whose expression levels were altered greater than two-fold compared to control cells. All five of the most down-regulated yeast genes are normally induced under low phosphate conditions via the PHO4 transcription factor, indicating that PsAvh110 perturbs the yeast regulatory network essential for phosphate homeostasis and suggesting likely PsAvh110 targets during P. sojae infection of its soybean host.

Keywords: Effectors; Functional genomics; Phosphate homeostasis; Phytopathology; Phytophthora sojae; RXLR; Saccharyomyces cerevisiae.

Grants and funding

This research was funded by the Agriculture and Food Research Initiative competitive grant 2011-68004-30104 of the USDA’s National Institute of Food and Agriculture, as well as The Henry J. Copeland Fund for Independent Study and The Theron L. Peterson and Dorothy R. Peterson Biology Research and Expense Fund at The College of Wooster. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.