Activation of Plant Innate Immunity by Extracellular High Mobility Group Box 3 and Its Inhibition by Salicylic Acid

PLoS Pathogens

Magali Moreau¹  Murli Manohar¹  Hyong Woo Choi¹  Miaoying Tian¹  Daniel F. Klessig¹  Patricia Manosalva¹ 

[1] Boyce Thompson Institute for Plant Research, Ithaca, New York, United States of America

关键词: Leaves;    Arabidopsis thaliana;    Immune response;    Apoplastic space;    Toll-like receptors;    Gene expression;    Genetically modified plants;    Ribulose-1;    5-bisphosphate carboxylase oxygenase;   

DOI  :  10.1371/journal.ppat.1005518

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Damage-associated molecular pattern molecules (DAMPs) signal the presence of tissue damage to induce immune responses in plants and animals. Here, we report that High Mobility Group Box 3 (HMGB3) is a novel plant DAMP. Extracellular HMGB3, through receptor-like kinases BAK1 and BKK1, induced hallmark innate immune responses, including i) MAPK activation, ii) defense-related gene expression, iii) callose deposition, and iv) enhanced resistance to Botrytis cinerea. Infection by necrotrophic B. cinerea released HMGB3 into the extracellular space (apoplast). Silencing HMGBs enhanced susceptibility to B. cinerea, while HMGB3 injection into apoplast restored resistance. Like its human counterpart, HMGB3 binds salicylic acid (SA), which results in inhibition of its DAMP activity. An SA-binding site mutant of HMGB3 retained its DAMP activity, which was no longer inhibited by SA, consistent with its reduced SA-binding activity. These results provide cross-kingdom evidence that HMGB proteins function as DAMPs and that SA is their conserved inhibitor.

【 授权许可】

CC BY