Conservation and divergence of flg22, pep1 and nlp20 in activation of immune response and inhibition of root development.

Abstract

Many pattern-recognition receptors (PRRs) and their corresponding ligands have been identified. However, it is largely unknown how similar and different these ligands are in inducing plant innate immunity and affecting plant development. In this study, we examined three well characterized ligands in Arabidopsis thaliana, namely flagellin 22 (flg22), plant elicitor peptide 1 (pep1) and a conserved 20-amino-acid fragment found in most necrosis and ethylene-inducing peptide 1-like proteins (nlp20). Our quantitative analyses detected the differences in amplitude in the early immune responses of these ligands, with nlp20-induced responses typically being slower than those mediated by flg22 and pep1. RNA sequencing showed the shared differentially expressed genes (DEGs) was mostly enriched in defense response, whereas nlp20-regulated genes represent only a fraction of those genes differentially regulated by flg22 and pep1. The three elicitors all inhibited primary root growth, especially pep1, which inhibited both auxin transport and signaling pathway. In addition, pep1 significantly inhibited the cell division and genes involved in cell cycle. Compared with flg22 and nlp20, pep1 induced much stronger expression of its receptor in roots, suggesting a potential positive feedback regulation in the activation of immune response. Despite PRRs and their co-receptor BAK1 were necessary for both PAMP induced immune response and root growth inhibition, bik1 mutant only showed impaired defense response but relatively normal root growth inhibition, suggesting BIK1 acts differently in these two biological processes.

• Authors: Yan Huang, Junmei Cui, Meng Li, Rongqian Yang, Yang Hu, Xiaosong Yu, Ying Chen, Qiqi Wu, Huipeng Yao, Guozhi Yu, Jinya Guo, Huaiyu Zhang, Shuang Wu, Yi Cai
• Journal: Plant science : an international journal of experimental plant biology (Plant Sci) Vol. 331 Pg. 111686 (Jun 2023) ISSN: 1873-2259 [Electronic] Ireland
• PMID: 36963637 (Publication Type: Journal Article)
• Copyright: Copyright © 2023 Elsevier B.V. All rights reserved.

Chemical References

• Flagellin
• Arabidopsis Proteins
• Peptides
• BIK1 protein, Arabidopsis
• Protein Serine-Threonine Kinases

Topics

• Flagellin (pharmacology, genetics)
• Arabidopsis (physiology)
• Arabidopsis Proteins (metabolism)
• Peptides (metabolism)
• Plant Immunity (genetics)
• Gene Expression Regulation, Plant
• Protein Serine-Threonine Kinases (metabolism)