Stephen B. Ryu, Jihye Jung and Sunghee Jung
KRIBB, 125 Gwahak-ro, Yuseong-gu, South Korea
Pathogen effector-triggered immune responses are mediated by host Resistance (R) proteins. The molecular mechanisms that connect these gene-for-gene interactions to the R gene-induced immune responses remain largely unknown. Here, we report that phospholipase A2 (PLA2) and its lipid products mediate R gene-induced immune responses in Arabidopsis. PLA2 is rapidly expressed in an R gene-mediated manner. PLA2 is secreted into the apoplast, where it generates its lipid products, including lysophosphatidylethanolamine (LPE), from invading bacteria and host cells. The Arabidopsis pla2 mutant lines fail to mount an adequate local immune response. The pla2 mutant defects are complemented by supplementation with LPE. Our results demonstrate PLA2-derived lipid signaling that mediates and/or potentiates R gene-induced immune responses following a gene-for-gene interaction.
Keywords: Lipid signaling, defense, Arabidopsis.