A substrate of the ABC transporter PEN3 stimulates bacterial flagellin (flg22)-induced callose deposition in Arabidopsis thaliana

作者：Andreas Matern, Christoph Böttcher, Lennart Eschen‐Lippold, Bernhard Westermann, Ulrike Smolka, Stefanie Döll, Fabian Trempel, Bibek Aryal, Dierk Scheel, Markus Geisler, Sabine Rosahl · 发表于：Journal of Biological Chemistry · 年份：2019 · DOI：10.1074/jbc.ra119.007676 · 被引用次数：58 · 研究领域：Legume Nitrogen Fixing Symbiosis、Soybean genetics and cultivation、Plant-Microbe Interactions and Immunity

Nonhost resistance of Arabidopsis thaliana against Phytophthora infestans , a filamentous eukaryotic microbe and the causal agent of potato late blight, is based on a multilayered defense system. Arabidopsis thaliana controls pathogen entry through the penetration-resistance genes PEN2 and PEN3 , encoding an atypical myrosinase and an ABC transporter, respectively, required for synthesis and export of unknown indole compounds. To identify pathogen-elicited leaf surface metabolites and further unravel nonhost resistance in Arabidopsis , we performed untargeted metabolite profiling by incubating a P. infestans zoospore suspension on leaves of WT or pen3 mutant Arabidopsis plants. Among the plant-secreted metabolites, 4-methoxyindol-3-yl-methanol and S -(4-methoxy-indol-3-yl-methyl) cysteine were detected in spore suspensions recollected from WT plants, but at reduced levels from the pen3 mutant plants. In both whole-cell and microsome-based assays, 4-methoxyindol-3-yl-methanol was transported in a PEN3-dependent manner, suggesting that this compound is a PEN3 substrate. The syntheses of both compounds were dependent on functional PEN2 and phytochelatin synthase 1. None of these compounds inhibited mycelial growth of P. infestans in vitro . Of note, exogenous application of 4-methoxyindol-3-yl methanol slightly elevated cytosolic Ca 2+ levels and enhanced callose deposition in hydathodes of seedlings treated with a bacterial pathogen-associated molecular pattern (PAMP), flagelli...