CATALASE2 Coordinates SA-Mediated Repression of Both Auxin Accumulation and JA Biosynthesis in Plant Defenses

Publication date: 8 February 2017
Source:Cell Host & Microbe, Volume 21, Issue 2
Author(s): Hong-Mei Yuan, Wen-Cheng Liu, Ying-Tang Lu
Plants defend against pathogen attack by modulating auxin signaling and activating the salicylic acid (SA) and jasmonic acid (JA) signaling pathways. SA and JA act antagonistically in resistance to specific pathogen types, yet how plants coordinate these phytohormones remains elusive. Here we report that biotrophic-pathogen-induced SA accumulation dampens both auxin and JA synthesis by inhibiting CATALASE2 (CAT2) activity in the model plant Arabidopsis. SA suppression of CAT2 results in increased H2O2 levels and subsequent sulfenylation of tryptophan synthetase β subunit 1, thus depleting the auxin biosynthetic precursor tryptophan. In addition, we find that CAT2 promotes JA biosynthesis by facilitating direct interaction of the JA biosynthetic enzymes ACX2 and ACX3, and thus SA repression of CAT2 inhibits JA accumulation. As such, the cat2-1 mutant exhibits increased resistance to biotrophic pathogens and increased susceptibility to necrotrophic pathogens. Our study illustrates how CAT2 coordinates SA repression of auxin accumulation and JA biosynthesis in plant defense.

Graphical abstract

Teaser

Salicylic acid, jasmonic acid, and auxin function in plant defense responses against biotrophic and necrotrophic pathogens. How these phytohormones are coordinated in plant immunity remains elusive. Yuan et al. showed that CATALASE2 coordinates salicylic-acid-mediated repression of auxin and jasmonic acid biosynthesis in plant resistance to different pathogens.


http://ift.tt/2kUXtsU