The role of plant microbiota in the evolution of fungal pathogens and their repertoires of secreted proteins

Introduction

Fungal plant pathogens have a devastating impact on crop production. Decades of research have addressed the molecular interaction of pathogens with plant immune responses and have established effector proteins as key molecules secreted by pathogens to interact with plant receptors.

Research Background

Studies of fungal pathogens have revealed a large diversity of predicted effector proteins expressed during plant colonization, yet the functional relevance of most remains unknown. I hypothesize that fungal pathogens secrete a diverse repertoire of effectors to manipulate host-associated microbiota and facilitate host invasion.

Hypotheses

As distinct plant species assemble distinct microbial communities, I hypothesize that:

1. Effector evolution and host specialization of pathogens, in part, is driven by the host-associated microbiota.

Project Overview: FungalSecrets

FungalSecrets will combine bioinformatics, evolutionary analyses, molecular microbiology approaches, and plant infection assays. Our research will focus on:

• 2000 effectors and effector-like proteins produced by four pathogens infecting wild relatives of crop plants.

Methodology

We will:

1. Predict the protein structures of effectors to identify new homology relationships and to make inferences of protein interactions and co-evolution.
2. Identify antimicrobial properties and determine the effect of each effector protein on the growth of 400 bacteria isolated from the host plants of the pathogens.
3. Overcome challenges of heterologous protein expression using different expression systems.

Detailed Analyses

To obtain mechanistic insights into microbial interactions, we will conduct detailed analyses of a selected set of candidate effectors with pleiotropic functions in virulence and microbiota manipulation.

Implications

FungalSecrets is based on innovative hypotheses and will cover a fundamental knowledge gap related to the ecology of fungal pathogens. The research will have implications for applied crop research and will stimulate new research of fungi associated with human and animal microbiota.