# A fungal pathogen manipulates phytocytokine signaling for plant infection

## TL;DR

A fungal pathogen uses a protein to suppress plant immunity by manipulating phytocytokine signaling.

## Contribution

The study reveals a novel mechanism by which a fungal effector promotes virulence through phytocytokine signaling.

## Key findings

- VdSCP8 suppresses plant immunity by interacting with PSKR1 and BAK1 to form a complex.
- SCP8 promotes PSK accumulation via a plant subtilase, enhancing immunosuppressive signaling.
- The effector's activity is crucial for the pathogen's ability to infect multiple plant hosts.

## Abstract

Phytocytokines, hormone-like plant peptides, play crucial roles in immune regulation and development. Phytosulfokine (PSK), known to mediate plant growth, also modulates plant pattern-triggered immunity (PTI). Here, we demonstrate that VdSCP8, a small cysteine-containing effector from Verticillium dahliae, functions as a virulence-promoting protein that suppresses PTI in Arabidopsis thaliana and Nicotiana benthamiana. Apoplastic SCP8 suppresses immune activation mediated by leucine-rich repeat ectodomain pattern recognition receptors. SCP8 virulence and immunosuppressive activities require PHYTOSULFOKINE RECEPTOR 1 (PSKR1), which binds PSK and forms a complex with co-receptor BAK1 to suppress PTI. Our findings underscore SCP8’s role in PTI suppression, facilitating PSKR1-BAK1 complex formation and promoting PSK accumulation through a plant subtilase. These results highlight how a multi-host plant pathogen manipulates PTI through enhancing immunosuppressive PSK signaling.

Phytocytokines play crucial roles in plant development and immunity. Here the authors show that VdSCP8, a small cysteine-containing effector from Verticillium dahliae, suppresses plant immunity by stimulating phytocytokine signaling.