A Conserved Peptide Pattern from a Widespread Microbial Virulence Factor Triggers Pattern-Induced Immunity in Arabidopsis

PLoS Pathogens

Hannah Böhm¹  Isabell Albert¹  Tom M. Raaymakers²  Guido Van den Ackerveken³  Stan Oome³  Thorsten Nürnberger³ 

[1] Center of Plant Molecular Biology (ZMBP)-Plant Biochemistry, Eberhard-Karls-University Tübingen, Tübingen, Germany;Centre for BioSystems Genomics (CBSG), Wageningen, The Netherlands;Plant-Microbe Interactions, Department of Biology, Utrecht University, Utrecht, The Netherlands

关键词: Arabidopsis thaliana;    Antigens;    Leaves;    Sequence motif analysis;    Plant disease resistance;    Oomycetes;    Ethylene;    Pattern recognition receptors;   

DOI  :  10.1371/journal.ppat.1004491

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Microbe- or host damage-derived patterns mediate activation of pattern-triggered immunity (PTI) in plants. Microbial virulence factor (effector)-triggered immunity (ETI) constitutes a second layer of plant protection against microbial attack. Various necrosis and ethylene-inducing peptide 1 (Nep1)-like proteins (NLPs) produced by bacterial, oomycete and fungal microbes are phytotoxic virulence factors that exert immunogenic activities through phytotoxin-induced host cell damage. We here show that multiple cytotoxic NLPs also carry a pattern of 20 amino acid residues (nlp20) that triggers immunity-associated plant defenses and immunity to microbial infection in Arabidopsis thaliana and related plant species with similar characteristics as the prototype pattern, bacterial flagellin. Characteristic differences in flagellin and nlp20 plant responses exist however, as nlp20s fail to trigger extracellular alkalinization in Arabidopsis cell suspensions and seedling growth inhibition. Immunogenic nlp20 peptide motifs are frequently found in bacterial, oomycete and fungal NLPs. Such an unusually broad taxonomic distribution within three phylogenetic kingdoms is unprecedented among microbe-derived triggers of immune responses in either metazoans or plants. Our findings suggest that cytotoxic NLPs carrying immunogenic nlp20 motifs trigger PTI in two ways as typical patterns and by inflicting host cell damage. We further propose that conserved structures within a microbial virulence factor might have driven the emergence of a plant pattern recognition system mediating PTI. As this is reminiscent of the evolution of immune receptors mediating ETI, our findings support the idea that there is a continuum between PTI and ETI.

【 授权许可】

CC BY