707 / 2019-05-02 22:39:14

Salicylic acid induces a small peptide that functions as an immune signal

Plant immunity,salicylic acid,small peptide

全体主题 > Plant Microbe Interactions & Microbiomes

A small peptide with 15 amino acids named as SA Induced Small Peptide (SAISP) was identified in Arabidopsis leaves after SA application through HPLC-MS/MS. Synthesized SAISP can activate the MAPK signaling pathway and induce the transcriptome change. When treating plants with SAISP 24 h before infection with the bacterial pathogen, Pseudomonas syringae pv tomato DC3000, SAISP treated plants showed significantly lower bacterial population growth compared with mock-treated plants. All these data suggest that the SAISP small peptide serves as an immune signal. To investigate how SAISP be recognized by plants, much effort was put into screening putative SAISP receptor (SAISPR). Two candidates SAISPR, SAISPR1 and SAISPR2 were identified. The mRNA level of SAISPR1 and SAISPR2 were significantly upregulated 1 hour after SAISP spray. The MAPK signaling activation and the plant defense genes induction were repressed in the saispr1-1 and saispr2-1 T-DNA insertion mutants, in which the mRNA expression levels of SAISPR1 and SAISPR2 were abolished, after treated with SAISP when compared with wild type. Although the saispr2-1 mutants demonstrated complete SAISP induced plant immunity, it was inhibited in the saispr1-1 mutants. The direct physical interaction of SAISP with SAISPR1 and SAISPR2 will be tested in vivo and in vitro in the future.