BnaABF2, a bZIP transcription factor from rapeseed (Brassica napus L.), enhances drought and salt tolerance in transgenic Arabidopsis

Abstract

BackgroundAbiotic stresses such as drought and salt stresses have a negative effect on the growth and productivity of plants. Improvement of stress tolerance through genetic engineering in plants has been reported in intense studies. Transcription factors play vital roles in plant adaptation to stresses by regulating expression of a great deal of target genes. A family of Arabidopsis basic region leucine zipper (bZIP) transcription factors that can recognize and bind to the abscisic acid (ABA)-responsive elements (ABREs) in promoter is named as ABRE binding factors (ABFs)/ABRE binding proteins (AREBs). They play a key role in the regulation of expression of downstream stress-responsive genes in ABA signalling. Genetic transformation of ABF/ABRE transcription factors has been suggested to be an effective approach for engineering stress-tolerant plants. However, whether the ABF/ABRE transcription factors are able to be used for generating stress-tolerant rapeseed plants has not yet been studied.Results BnaABF2, encoding a bZIP transcription factor, was cloned from rapeseed in this study. Subcellular localization and transactivation analyses showed that BnaABF2 was localized to the nucleus with transactivation activity in plant cells. BnaABF2 gene expression was induced by drought and salt stresses and BnaABF2 positively functions in ABA signalling during the vegetative stage. Overexpression of BnaABF2 was found to render drought and salt tolerance to Arabidopsis plants. The resistance of the BnaABF2-expressing transgenic plants to drought and salt stresses is due to reduced water-loss rate and expression of stress-responsive genes such as RD29B, RAB18 and KIN2. The expression of RD29B, RAB18 and KIN2 regulated by BnaABF2 is involved in an ABA-dependent stress signalling.ConclusionsIdentification of the positive role of rapeseed BnaABF2 in plant tolerance to drought and salt provides evidence for ability of engineering stress-tolerant rapeseed plants by genetic transformation of BnaABF2.Electronic supplementary materialThe online version of this article (doi:10.1186/s40529-016-0127-9) contains supplementary material, which is available to authorized users.

Exploring transcription factors reveals crucial members and regulatory networks involved in different abiotic stresses in Brassica napus L.

“…The five TF families play important roles during stress response in plants [ 30 , 32 , 35 , 40 ]. For B. napus , we consider five treatments, including cold, heat, drought, salt and ABA ( Material and methods ).…”

“…Hwang et al identified 136 BrbZIPs [ 31 ] in B. rapa and 119 BobZIPs [ 24 ] in B. oleracea , and cold responsiveness of these TFs were investigated by using RNA-Seq and qRT-PCR. Zhao et al [ 32 ] found that the expression of a bZIP gene, BnABF2 in B. napus , could be induced by drought and salt stresses. Zhou et al [ 8 ] identified 247 BnbZIPs in B. napus and performed detailed structural analyses.…”

The Expression of CARK1 or RCAR11 Driven by Synthetic Promoters Increases Drought Tolerance in Arabidopsis thaliana

“…In addition, these synthetic promoters contained DREs and ABREs. DREB2A (dehydration-responsive element binding protein 2A) regulates DRE-mediated element of genes under osmotic stress conditions in Arabidopsis [ 41 , 42 ], and ABRE binding factors (ABFs)/ABRE binding proteins (AREBs) are highly induced by ABA and then interact with ABREs to cause gene expression [ 43 ]. To further determine whether the synthetic promoters were induced by DREB2A or ABA, the ratio of FLUC (Firefly luciferase)/RLUC (Renilla luciferase) was analyzed in Arabidopsis protoplasts by the dual-luciferase reporter system.…”

Engineering Multiple Abiotic Stress Tolerance in Canola, Brassica napus

“…In B. napus 247 bZIP TFs have been identified, and their differential expression in various tissues and organs has been reported (Zhou et al, 2017). Zhao B. Y., et al (2016) reported the expression of BnABF2 (gene encoding bZIP factor) in response to drought and salt stress. Further, overexpression of BnABF2 in Arabidopsis conferred drought and salt resistance due to regulation of RD29B, RAB18, and KIN2 genes under these stresses in an ABA-dependent manner.…”