Proteomic analysis of differentially expressed proteins of Nicotiana benthamiana triggered by INF1 elicitin from Phytophthora infestans

Abstract

Pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) is considered to be durable, given that PAMPs are conserved in entire classes of microbes. Elicitins are structurally conserved extracellular proteins in oomycete species and are well characterized as having features of PAMPs. INF1 is an elicitin protein secreted by the late blight pathogen Phytophthora infestans. A cell surface receptor-like protein that mediates INF1 response was recently cloned in potato. In addition, some other genes are reportedly involved in INF1-triggered immune responses; however, the molecular mechanisms of INF1-triggered immunity remain poorly understood. Here, we used isobaric tags for relative and absolute quantification-based quantitative proteomics to analyze proteins involved in INF1-triggered cell death responses in Nicotiana benthamiana. Our approach identified 2964 proteins, 32 of which were significantly altered in abundance after INF1 induction. Two of eight selected upregulated proteins, namely, ATP dependent transporter and 60S ribosomal protein L15 were shown to be essential in INF1-triggered cell death responses by virus-induced gene silencing analysis. This study represents the first proteomic analysis of INF1-triggered cell death responses in plants and provides the basis for further work to elucidate molecular mechanisms into oomycete PTI in host plants.