A type II secreted subtilase from commensal rhizobacteria disarms the immune elicitor peptide flg22

Authors: EASTMAN, SAMUEL - Princeton University; JIANG, TING - Princeton University; FICCO, KAELI - Princeton University; LIAO, CHAO - Princeton University; WEN, SARINA - Princeton University; BIDDLE, YVETTE - Princeton University; EYCEOZ, AYA - Princeton University; JONES, BRITLEY - Princeton University; YATSISHIN, ILYA - Princeton University; Naumann, Todd; CONWAY, JONATHAN - Princeton University

Submitted to: Cell Host and Microbe
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/21/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: The soil is filled with bacteria. As some cause disease, plants prevent them from growing near their roots. But unnecessarily fighting against harmless bacteria reduces plant health and, in crops, yield. In this work ARS scientists in Peoria, Illinois, working with scientists at Princeton University, studied how some harmless soil bacteria are able to grow near roots. They discovered that these bacteria dampen plant defenses by producing a specific protein—that they named IssA—that degrades flg22, a bacterial peptide that is the main chemical messenger that triggers plant antibacterial defenses. From a biological perspective this discovery helps scientists understand how plants and harmless bacteria communicate to create healthy soils. From an agricultural perspective this discovery suggests that crop yield and harvest quality can be improved by field application of these bacteria, promising to save farmers money and improve food safety for consumers.

Technical Abstract: Plants grow in association with a community of microorganisms collectively known as the rhizosphere microbiome. Immune activation in response to elicitors like the flagellin-derived epitope flg22 restricts bacteria on plant roots but also restricts plant growth. Some commensal rhizobacteria are capable of suppressing the plant immune response to elicitors. In this study, we investigated the ability of 165 root-associated bacteria to suppress flg22-induced immune activation and growth restriction. We demonstrate that a type II secreted subtilase from Dyella japonica and other commensal Xanthamonadales cleaves the immune eliciting peptide flg22 and contributes to immune suppression.