Switchgrass PvDREB1C plays opposite roles in plant cold and salt tolerance in transgenic tobacco

Guohui Yu,Jing Zhang,Linkai Huang,Zheni Xie,Bingru Huang,Chengliang Zhao,Bin Xu,Wuwu Wen

doi:10.1186/s41065-017-0050-4

Abstract

BackgroundThe C-repeat-binding factors/DRE-binding factors (CBF/DREBs) comprise a key transcription factor family involved in plant stress tolerance. Yet, there is limited information about switchgrass DREB genes and their functional roles.ResultsIn this study, four cold-inducible PvDREB1s were identified from switchgrass (Panicum virgatum), among which PvDREB1C was the one responded to cold stress later than the other three PvDREB1s. Yet, ectopic overexpression of PvDREB1C led to significantly compromised, instead of improved cold tolerance in transgenic tobacco. On the other hand, PvDREB1C was transcriptionally down-regulated in response to salt stress, but overexpression of PvDREB1C improved plant salt tolerance in transgenic tobacco. The improved salt tolerance was associated with increased K+/Na+ ratio and Ca2+ content, higher cellular osmotic potential, and activation of stress-related functional genes in the leaves of transgenic plants under salt stress.ConclusionsThe current results implied that PvDREB1C played opposite roles in plant cold and salt tolerance. Although DREB1s were known as positive stress regulators, particular attentions shall be paid to their potential negative regulatory role(s).

Highlights

The C-repeat-binding factors/Dehydrationresponsive element (DRE)-binding factors (CBF/Dehydration-responsive element binding factor (DREB)) comprise a key transcription factor family involved in plant stress tolerance
Four switchgrass DREB1 genes transcriptionally responsive to cold exposure In searching for CBFs/DREB1s involved in cold tolerance in switchgrass, four rice cold-responsive DREB1s [i.e. OsDREB1A (Os09g0522200), OsDREB1B (Os09g0522000), OsDREB1C (Os06g0127100), OsDREB1G (Os02g0677300) [10, 11] were used to search corresponding orthologs against the switchgrass genome database (Panicum virgatum v1.1, DOE-JGI) using BLAST
According to the phylogenetic analysis (Fig. 1a), these PvDREB1s were named as PvDREB1A-1/−2 (Pavir.J03891.1 & Pavir.Ba01280.1), PvDREB1B-1/−2 (Pavir.J19655.1 & Pavir.Ba01283.1), PvDREB1C (Pavir.J35991.1), and PvDREB1G-1/−2 (Pavir.Ab02685.1 & Pavir.Aa00912.1)

Summary

Introduction

The C-repeat-binding factors/DRE-binding factors (CBF/DREBs) comprise a key transcription factor family involved in plant stress tolerance. There is limited information about switchgrass DREB genes and their functional roles. Switchgrass (Panicum virgatum) is a perennial, C4 tall grass used for biofuel and forage feedstock production, water and soil conservation, as well as habitat restoration [1,2,3]. Switchgrass is known for its wide adaptation to diverse and relatively harsh environment [4]. The C-repeat-binding factors/DRE-binding factors (CBF/ DREBs) constitute an indispensable regulatory network for plant tolerance against abiotic stresses (e.g. cold, drought and salinity, etc.) [5]. DREBs primarily function through transactivating the expression of downstream functional genes through binding to the C-repeat/dehydration responsive (CRT/DRE) cis-elements [6].

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