SlDEAD31, a Putative DEAD-Box RNA Helicase Gene, Regulates Salt and Drought Tolerance and Stress-Related Genes in Tomato.

Jianling Zhang,Zhiping Zhao,Lingling Wang,Guoping Chen,Mingku Zhu,Zongli Hu,Girdhar K Pandey,Tingting Dong

doi:10.1371/journal.pone.0133849

Abstract

The DEAD-box RNA helicases are involved in almost every aspect of RNA metabolism, associated with diverse cellular functions including plant growth and development, and their importance in response to biotic and abiotic stresses is only beginning to emerge. However, none of DEAD-box genes was well characterized in tomato so far. In this study, we reported on the identification and characterization of two putative DEAD-box RNA helicase genes, SlDEAD30 and SlDEAD31 from tomato, which were classified into stress-related DEAD-box proteins by phylogenetic analysis. Expression analysis indicated that SlDEAD30 was highly expressed in roots and mature leaves, while SlDEAD31 was constantly expressed in various tissues. Furthermore, the expression of both genes was induced mainly in roots under NaCl stress, and SlDEAD31 mRNA was also increased by heat, cold, and dehydration. In stress assays, transgenic tomato plants overexpressing SlDEAD31 exhibited dramatically enhanced salt tolerance and slightly improved drought resistance, which were simultaneously demonstrated by significantly enhanced expression of multiple biotic and abiotic stress-related genes, higher survival rate, relative water content (RWC) and chlorophyll content, and lower water loss rate and malondialdehyde (MDA) production compared to wild-type plants. Collectively, these results provide a preliminary characterization of SlDEAD30 and SlDEAD31 genes in tomato, and suggest that stress-responsive SlDEAD31 is essential for salt and drought tolerance and stress-related gene regulation in plants.

Highlights

Plants, as sessile organisms, are continuously exposed to various environmental stresses such as salinity, drought, low temperature, and UV light, which can cause damage to lipids, proteins and DNA, reducing plants genome stability, growth, and productivity [1, 2]
SlDEAD30 protein shares a close relationship with AtRH36 (66.4% identity, S1 Table), which is essential for Arabidopsis female gametogenesis [25], whereas SlDEAD31 is much closer related to AtRH9 (79.9% identity, S1 Table), which has an important role in cold tolerance in Arabidopsis [21]
The involvement and significance of RNA helicases in response to biotic and abiotic stresses have only recently begun to emerge, and Vashisht and Tuteja

Summary

Introduction

As sessile organisms, are continuously exposed to various environmental stresses such as salinity, drought, low temperature, and UV light, which can cause damage to lipids, proteins and DNA, reducing plants genome stability, growth, and productivity [1, 2]. Plants respond to these stresses via the cascades of molecular networks and changes in expression profiles of PLOS ONE | DOI:10.1371/journal.pone.0133849. SlDEAD31 Plays a Role in Salt and Drought Tolerance Plants respond to these stresses via the cascades of molecular networks and changes in expression profiles of PLOS ONE | DOI:10.1371/journal.pone.0133849 August 4, 2015

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Conclusion