Membrane-triggered plant immunity.

Plants have evolved sophisticated defense mechanisms to resist pathogen invasion. Upon the pathogen recognition, the host plants activate a variety of signal transduction pathways, and one of representative defense responses is systemic acquired resistance (SAR) that provides strong immunity against secondary infections in systemic tissues. Accumulating evidence has demonstrated that modulation of membrane composition contributes to establishing SAR and disease resistance in Arabidopsis, but underlying molecular mechanisms remain to be elucidated. Here, we show that a membrane-bound transcription factor (MTF) is associated with plant responses to pathogen attack. The MTF is responsive to microbe-associated molecular pattern (MAMP)-triggered membrane rigidification at the levels of transcription and proteolytic processing. The processed nuclear transcription factor possibly regulates pathogen resistance by directly regulating PATHOGENESIS-RELATED (PR) genes. Taken together, our results suggest that pathogenic microorganisms trigger changes in physico-chemical properties of cellular membrane in plants, and the MTF conveys the membrane information to the nucleus to ensure prompt establishment of plant immunity.