ITRAQ proteomics reveals the regulatory response to Magnaporthe oryzae in durable resistant vs. susceptible rice genotypes.

Zuobin Ma,Hong Gao,Yongan Yin,Changhua Wang,Wenjing Zheng,Mingzhu Zhao,Na He,Liying Zhang,Zhengjin Xu,Zhiqiang Tang,Jiaming Zhao,Lili Wang,Shuang Gu,Liang Fu,Binod Bihari Sahu

doi:10.1371/journal.pone.0227470

Abstract

Rice blast disease caused by Magnaporthe oryzae (M. oryzae) is one of the most serious diseases. Although previous research using two-dimensional gel-based proteomics to assess the proteins related to the rice blast resistance had been done, few proteins were identified. Here, we used the iTRAQ method to detect the differentially expressed proteins (DEPs) in the durable resistant rice variety Gangyuan8 (GY8) and the susceptible rice variety Lijiangxintuanheigu (LTH) in response to M. oryzae invasion, and then transcriptome sequencing was used to assist analysis A total of 193 and 672 DEPs were specifically identified in GY8 and LTH, respectively, with only 46 similarly expressed DEPs being shared by GY8 and LTH.39 DEPs involved in plant-pathogen interaction, plant hormone signal transduction, fatty acid metabolism and peroxisome biosynthesis were significantly different between compatible interaction (LTH) and incompatible interaction (GY8). Some proteins participated in peroxide signal transduction and biosynthesis was down-regulated in GY8 but up-regulated in LTH. A lot of genes encoding pathogenesis-related gene (PR), such as chitinase and glucanase, were significantly up-regulated at both the transcriptome and proteome levels at 24 hours post-inoculation in GY8, but up-regulated at the transcriptome level and down-regulated at the proteome level in LTH. Our study reveals that the pathogen-associated molecular pattern (PAMP)-triggered immunity defense system may be activated at the transcriptome level but was inhibited at the protein level in susceptible rice varieties after inoculation. The results may facilitate future studies of the molecular mechanisms of rice blast resistance.

Highlights

IntroductionTo combat M. oryzae, rice has formed two immune system, named pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and effector-triggered immunity (ETI) [4, 5]
Rice blast, caused by Magnaporthe oryzae L., is the most destructive disease in rice (Oryza sativa) [1] and reduces global yields annually by 10%–15% [2, 3].Knowledge on the broadspectrum resistance mechanism to rice blast is of great significance for the disease resistance breeding and diseases control.To combat M. oryzae, rice has formed two immune system, named pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and effector-triggered immunity (ETI) [4, 5]
Our study revealed that several pathways, including plant–pathogen interaction, plant hormone signal transduction, fatty acid metabolism, and peroxisome biosynthesis, were restrained in the susceptible variety.WRKY, C2H2, and other transcription factors (TFs) were detected in the transcriptome than in the proteome, and Plant defense-related genes were depressed in the proteome of LTH and up-regulated in the transcriptome

Summary

Introduction

To combat M. oryzae, rice has formed two immune system, named pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and effector-triggered immunity (ETI) [4, 5]. PTI was considered the first line of defense and conferd durable and broad-spectrum resistance. In this system, pattern recognition receptors (PRRs) can recognize PAMPs which are widely conserved in pathogens trigger a weakly immune response [6]. Plant PRRs contained transmembrane receptor-like kinases (RLKs) and receptor-like proteins (RLPs). ETI, as the second layer of the plant innate immune, is initiated by archetypical resistance (R) proteins that directly or indirectly recognize effectors secreted into the plant cells by the pathogen. Unlike PAMPs, effectors are highly variable, and the disease resistance mediated by ETI is generally race-specific [6]

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