Regulatory Network Identification, Promoter and Expression Analysis of Arabidopsis thaliana NPR1 in Defense Responses against Stresses

Amir G Shahriari,Sima Sazegari,Aminallah Tahmasebi

doi:10.15835/nsb10310311

Amir G Shahriari, Sima Sazegari + Show 1 more

Open Access

https://doi.org/10.15835/nsb10310311

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Abstract

Salicylic acid (SA) and jasmonic acid (JA) phytohormones have been known for their roles in plant defense behaviour against biotic and abiotic stresses. They regulate defense pathways by antagonistic interaction. NPR1 as a key regulatory factor in the cross-talk between SA and JA, signaling is essential for the inhibition of JA-responsive gene expression by SA. In silico promoter analysis of 1.5 kb promoter regions of NPR1 gene revealed that NPR1 contains 23 MYB and 20 WRKY transcription factor binding sites. Different cis-elements associated with various stress responses were identified in Arabidopsis thaliana NPR1. The most common element was allocated to the defense responses against biotic stresses. Based on gene network analysis, NPR1, TGA2 and TGA3 were predicted to have functional cooperation with each other. Affymetrix microarray data analysis of A. thaliana under SA treatment demonstrated that most genes involved in NPR1 network are up-regulated under SA treatment. Therefore, interaction and cooperation between these factors might serve to fine-tune regulation of defense and immune responses against biotic and abiotic stresses.

Highlights

Plants are exposed to various biotic and abiotic stresses
Salicylic acid (SA) and jasmonic acid (JA) phytohormones have been known for their roles in plant defense behaviour against biotic and abiotic stresses
Different cis-elements associated with various stress responses were identified in Arabidopsis thaliana NPR1

Summary

Introduction

Plants are exposed to various biotic and abiotic stresses. Perception of stress signals often results in the biosynthesis of signaling molecules like jasmonic acid (JA) and salicylic acid (SA) phytohormones (Turner et al, 2002; Shah, 2003). The activation of SA biosynthesis or signaling in many plant-pathogen interactions has been shown to result in the inhibition of JA biosynthesis or signaling through non-expresser of pathogenesis-related genes 1) (NPR) and WRKY70 proteins (Koornneef and Pieterse, 2008; Yasuda et al, 2008; Bari and Jones, 2009; Antico et al, 2012; Thaler et al, 2012). TFs can interact with jasmonate signaling pathway and mediate response to biotic and abiotic stresses (Century et al, 2008). The identification of CAREs and their interaction with TFs could give some insight into the plant defense against stresses and presents a comprehensive understanding of the regulation of NPR1 gene expression. In the present study, in silico promoter analysis and affymetrix microarray data analysis of A. thaliana under salicylic acid treatment was followed to study NPR1 CAREs, TFs and expression analysis of genes involved in Arabidopsis thaliana NPR1 signaling network which are involved in defense responses against biotic and abiotic stresses. Due to the pivotal role of transcription factors, such studies will advance the knowledge of host-stress interactions and can further provide the development of new strategies for the plant genetic engineering for management of biotic and abiotic stresses

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