Tomato NAC transcription factor SlSRN1 positively regulates defense response against biotic stress but negatively regulates abiotic stress response.

Bo Liu,Shixia Liu,Lei Huang,Dayong Li,Zhigang Ouyang,Yafen Zhang,Xiaohui Li,Yongbo Hong,Fengming Song,Huijuan Zhang,Hua Lu

doi:10.1371/journal.pone.0102067

Abstract

Biotic and abiotic stresses are major unfavorable factors that affect crop productivity worldwide. NAC proteins comprise a large family of transcription factors that play important roles in plant growth and development as well as in responses to biotic and abiotic stresses. In a virus-induced gene silencing-based screening to identify genes that are involved in defense response against Botrytis cinerea, we identified a tomato NAC gene SlSRN1 (Solanum lycopersicum Stress-related NAC1). SlSRN1 is a plasma membrane-localized protein with transactivation activity in yeast. Expression of SlSRN1 was significantly induced by infection with B. cinerea or Pseudomonas syringae pv. tomato (Pst) DC3000, leading to 6–8 folds higher than that in the mock-inoculated plants. Expression of SlSRN1 was also induced by salicylic acid, jasmonic acid and 1-amino cyclopropane-1-carboxylic acid and by drought stress. Silencing of SlSRN1 resulted in increased severity of diseases caused by B. cinerea and Pst DC3000. However, silencing of SlSRN1 resulted in increased tolerance against oxidative and drought stresses. Furthermore, silencing of SlSRN1 accelerated accumulation of reactive oxygen species but attenuated expression of defense genes after infection by B. cinerea. Our results demonstrate that SlSRN1 is a positive regulator of defense response against B. cinerea and Pst DC3000 but is a negative regulator for oxidative and drought stress response in tomato.

Highlights

IntroductionPlants constantly encounter various biotic (i.e. pathogen infection) and abiotic (i.e. drought, high salinity and extreme temperature conditions) stresses that significantly affect both biomass growth and yield production
Plants constantly encounter various biotic and abiotic stresses that significantly affect both biomass growth and yield production
Characterization of SlSRN1 To explore the molecular basis of defense response in tomato against necrotrophic fungal pathogens, we performed VIGS-based screening to identify genes that are involved in defense response to B. cincrea

Summary

Introduction

Plants constantly encounter various biotic (i.e. pathogen infection) and abiotic (i.e. drought, high salinity and extreme temperature conditions) stresses that significantly affect both biomass growth and yield production. Upon perception of the environmental cues, initiation of the signaling network leads to activation of a large set of genes, which are regulated by different types of transcription factors (TFs). Numerous TFs belonging to the different families such as NAC, ERF, MYB, WRKY, and bZIP families have been identified to play important roles in regulating plant responses to biotic and abiotic stresses [1,2,3,4,5]. The involvement and function of the NAC proteins in plant responses to biotic and abiotic stresses have been well documented in model plants and in various crop plants (for reviews, see [4,15,19,20]). It is believed that the NAC proteins can be used as useful functional gene resources for improvement of biotic and abiotic stress tolerance in crops [15,19,21]

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