Sterol-Dependent Induction of Plant Defense Responses by a Microbe-Associated Molecular Pattern from Trichoderma viride

Miya Sharfman,Maya Bar,Silvia Schuster,Adi Avni,Meirav Leibman

doi:10.1104/pp.113.230136

Miya Sharfman, Maya Bar + Show 3 more

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https://doi.org/10.1104/pp.113.230136

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Journal: Plant Physiology	Publication Date: Dec 18, 2013
Citations: 18	License type: CC BY 4.0

Affiliation: Tel Aviv University

Abstract

Plant-microbe interactions involve numerous regulatory systems essential for plant defense against pathogens. An ethylene-inducing xylanase (Eix) of Trichoderma viride is a potent elicitor of plant defense responses in specific cultivars of tobacco (Nicotiana tabacum) and tomato (Solanum lycopersicum). We demonstrate that tomato cyclopropyl isomerase (SlCPI), an enzyme involved in sterol biosynthesis, interacts with the LeEix2 receptor. Moreover, we examined the role of SlCPI in signaling during the LeEix/Eix defense response. We found that SlCPI is an important factor in the regulation of the induction of defense responses such as the hypersensitive response, ethylene biosynthesis, and the induction of pathogenesis-related protein expression in the case of LeEix/Eix. Our results also suggest that changes in the sterol composition reduce LeEix internalization, thereby attenuating the induction of plant defense responses.

Highlights

Plant innate immunity is activated upon the recognition of pathogen- and microbe-associated molecular patterns by surface-localized immune receptors or the stimulation of cytoplasmic immune receptors by pathogen effector proteins (Jones and Dangl, 2006; Thomma et al, 2011)
To study the signal transduction pathway leading to the induction of innate immunity mediated by ethylene-inducing xylanase (Eix), we searched for proteins interacting with the LeEix2 receptor (Ron and Avni, 2004)
One complementary DNA (cDNA) that was identified as SlCPI showed 72% sequence identity and 89% similarity to AtCPI1 of Arabidopsis, which is involved in sterol biosynthesis

Summary

Introduction

Plant innate immunity is activated upon the recognition of pathogen- and microbe-associated molecular patterns by surface-localized immune receptors or the stimulation of cytoplasmic immune receptors by pathogen effector proteins (Jones and Dangl, 2006; Thomma et al, 2011). Leucine-rich repeat (LRR) receptor kinases and leucinerich repeat receptor proteins (LRR-RLPs) respond to conserved microbe-associated molecular patterns by producing a defense response upon detection (Altenbach and Robatzek, 2007; Bittel and Robatzek, 2007; Robatzek et al, 2007; Geldner and Robatzek, 2008). One such LRRRLP is the ethylene-inducing xylanase (Eix) receptor LeEix. Sterols were shown to function in the trafficking of an ATP-binding cassette (ABCB19) from the trans-Golgi to the plasma membrane (Yang et al, 2013)

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