# How plants manage pathogen infection

## TL;DR

This review explains how plants use immune responses and microbiota to suppress pathogens and identifies remaining questions in this area.

## Contribution

The paper highlights the underexplored third step of plant immunity and the role of the plant microbiota in pathogen suppression.

## Key findings

- Plant immune responses include microbial recognition, signal transduction, and immune execution.
- Recent evidence shows the plant microbiota contributes to direct pathogen suppression.
- The third step of plant immunity, immune execution, remains poorly understood.

## Abstract

To combat microbial pathogens, plants have evolved specific immune responses that can be divided into three essential steps: microbial recognition by immune receptors, signal transduction within plant cells, and immune execution directly suppressing pathogens. During the past three decades, many plant immune receptors and signaling components and their mode of action have been revealed, markedly advancing our understanding of the first two steps. Activation of immune signaling results in physical and chemical actions that actually stop pathogen infection. Nevertheless, this third step of plant immunity is under explored. In addition to immune execution by plants, recent evidence suggests that the plant microbiota, which is considered an additional layer of the plant immune system, also plays a critical role in direct pathogen suppression. In this review, we summarize the current understanding of how plant immunity as well as microbiota control pathogen growth and behavior and highlight outstanding questions that need to be answered.

Plants have evolved specific immune responses to directly suppress infiltrated pathogens. This review summarizes our current understanding of how plant immunity controls pathogen growth and behavior and highlights outstanding questions on pathogen suppression.