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

Area of Science:

• Plant Pathology
• Molecular Biology
• Eukaryotic Model Systems

Background:

• Phytophthora pathogens secrete effector proteins into host cells to promote infection.
• A subset of these effectors contain the conserved RXLR (arginine, any amino acid, leucine, arginine) motif.
• The functions of most identified RXLR effectors remain largely uncharacterized.

Purpose of the Study:

• To investigate the utility of Saccharomyces cerevisiae (yeast) as a model system for functional analysis of Phytophthora RXLR effectors.
• To explore the molecular mechanisms of RXLR effector action in a heterologous eukaryotic system.

Main Methods:

• Expression of individual Phytophthora RXLR effectors in S. cerevisiae.
• Assessment of yeast growth inhibition upon effector expression.
• Transcriptome analysis (RNA sequencing) of yeast expressing the P. sojae effector Avh110 (PsAvh110).

Main Results:

• Expression of individual RXLR effectors in yeast led to growth inhibition, suggesting interference with conserved cellular processes.
• PsAvh110 expression significantly altered the expression levels of numerous yeast genes.
• The most downregulated genes in PsAvh110-expressing yeast are involved in phosphate homeostasis and regulated by the PHO4 transcription factor.

Conclusions:

• S. cerevisiae serves as a viable model for studying Phytophthora RXLR effector function.
• PsAvh110 perturbs the yeast phosphate regulatory network, indicating its role in phosphate homeostasis.
• This study suggests potential targets for PsAvh110 within the soybean host during P. sojae infection.