A WRKY transcription factor, FtWRKY46, from Tartary buckwheat improves salt tolerance in transgenic Arabidopsis thaliana

doi:10.1016/j.plaphy.2019.12.004

Plant Physiology and Biochemistry

Volume 147, February 2020, Pages 43-53

https://doi.org/10.1016/j.plaphy.2019.12.004 Get rights and content

Highlights

•
FtWRKY46 may activate the expression of target genes by binding to W-box elements in the nucleus.
•
The ectopic expression of FtWRKY46 resulted in increased salt tolerance in transgenic Arabidopsis.
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FtWRKY46 plays a negative regulatory role in the ABA signaling pathway and participates in plant responses to salt stress.

Abstract

The WRKY transcription factor family includes plant-specific transcription factors that are widely involved in plant biotic and abiotic stress responses, growth and development. Tartary buckwheat is a type of small grain with strong resistance to adverse growing conditions. No systematic exploration of the WRKY family in Tartary buckwheat has yet been reported. In this paper, we report the FtWRKY46 gene from Tartary buckwheat and study its role in salt tolerance. FtWRKY46 has transcriptional activation activity in yeast, and FtWRKY46 fused to yellow fluorescent protein localizes to the nucleus. Further studies have found that its transcriptional activation region is located at the N-terminus. A yeast one-hybrid assay indicated that FtWRKY46 could bind to a W-box and activate reporter gene expression. Similarly, transient cotransfection showed that FtWRKY46 could specifically bind to W-box regions and activate reporter gene expression in plants. Furthermore, ectopic expression of FtWRKY46 could enhance Arabidopsis tolerance to salt stress. More specifically, the seed germination rate, root length, chlorophyll content and proline content were significantly higher in transgenic plants ectopically expressing FtWRKY46 than in WT plants after salt stress (P < 0.05), while MDA levels were significantly lower than in WT plants (P < 0.05). Additionally, salt treatment increased the expression of stress-related genes. To summarize, our results suggest that ectopic expression of FtWRKY46 enhance the stress tolerance of transgenic plants by modulating ROS clearance and stress-related gene expression.

Section snippets

1Introduction

Soil salinization seriously restricts sustainable agricultural production by affecting plant seed germination, crop growth and yield (Cai et al., 2017). A high-salt environment will destroy the ion balance in plant cells, promoting the accumulation of excessive amounts of Na⁺ and Cl⁻, and cause severe osmotic stress, which affects the water absorption capacity of plant cells (Marshall et al., 2012). The negative effects of salt stress can lead to disturbances in all physiological and metabolic

Plant materials, growth conditions and treatment conditions

The material used in this experiment is Tartary buckwheat (“Xiqiao No. 2”). The seeds were germinated under artificial climate room conditions (25 °C, 100 μmol photons m⁻² s⁻¹, 60% relative humidity, 16/8 h day/night cycles). Fourteen-day-old Tartary buckwheat sprouts were subjected to the following stress treatment conditions: 150 mM NaCl for salinity, 30% (w/v) PEG 6000 and 100 μM ABA for drought, and ABA treatment. Seedlings were reaped at 0, 0.5, 1, 2, 3, 6 and 10 h after treatment, and the

Cloning and phylogenetic analysis of FtWRKY46

FtWRKY46 was obtained by transcriptome data screening. The FtWRKY46 gene (GenBank accession number: MK910374) was isolated from Tartary buckwheat. The FtWRKY46 cDNA sequence is 1083 bp long and encodes a 360-amino acid protein. The predicted molecular weight of FtWRKY46 is 40.74 KD, and the theoretical isoelectric point is 6.07. Blast showed high homology between FtWRKY46 and cotton GhWRKY41 in NCBI (https://www.ncbi.nlm.nih.gov/) (Fig. 1A). Multiple sequence alignment showed that FtWRKY46

Discussion

Increasing attention has been paid to WRKY TFs, one of the largest families of transcription factors in higher plants. Sweet potato SPF1 was the first WRKY transcription factor cloned in plants(Ishiguro and Nakamura, 1994). The functions and mechanisms of action of many WRKY transcription factor families have been studied, particularly in terms of biotic and abiotic stresses (Dai et al., 2016; Kiranmai et al., 2018). However, no WRKY transcription factor has been reported in Tartary buckwheat.

Author contributions

BBL and QW performed most of the experiments and all of the data analyses.

AHW provided the seeds of “Xiqiao No. 2”.

QL performed the plasmid constructions and real-time PCR.

QXD carried out part of the material collection and RNA extraction.

JJY assisted in plasmid construction and Arabidopsis transformation.

HXZ, XLW and HC participated in the preparation of the manuscript.

CLL conceived and designed the studies.

All authors have read and approved the final manuscript.

Declaration of competing interest

The authors have no conflicts of interest to declare.

Acknowledgments

This research was supported by the National Natural Science Foundation of China (3187101578).

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¹: These authors contributed equally to this work.

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Research articleA WRKY transcription factor, FtWRKY46, from Tartary buckwheat improves salt tolerance in transgenic Arabidopsis thaliana

Highlights

Abstract

Section snippets

1Introduction

Plant materials, growth conditions and treatment conditions

Cloning and phylogenetic analysis of FtWRKY46

Discussion

Author contributions

Declaration of competing interest

Acknowledgments

Biochim. Biophys. Acta

Trends Plant Sci.

Curr. Opin. Plant Biol.

Plant Physiol. Biochem.

J. Plant Physiol.

Plant Physiol. Biochem.

Plant Physiol. Biochem.

Mol. Plant

Curr. Opin. Plant Biol.

Trends Plant Sci.

Curr. Biol.

Biochem. Biophys. Res. Commun.

Biochem. Biophys. Res. Commun.

Mol. Plant

Trends Plant Sci.

Effects of light-emitting diodes on expression of phenylpropanoid biosynthetic genes and accumulation of phenylpropanoids in Fagopyrum tataricum sprouts

J. Agric. Food Chem.

A WRKY transcription factor, PcWRKY33, from Polygonum cuspidatum reduces salt tolerance in transgenic Arabidopsis thaliana

Plant Cell Rep.

Expression of cell cycle regulatory genes and morphological alterations in response to salt stress in Arabidopsis thaliana

Planta

The maize WRKY transcription factor ZmWRKY17 negatively regulates salt stress tolerance in transgenic Arabidopsis plants

Planta

The cotton WRKY gene GhWRKY41 positively regulates salt and drought stress tolerance in transgenic Nicotiana benthamiana

PLoS One

Floral dip: a simplified method for Agrobacterium-mediated transformation of Arabidopsis thaliana

Plant J. : Cell Mol. Biol.

The transcription factor FcWRKY40 of Fortunella crassifolia functions positively in salt tolerance through modulation of ion homeostasis and proline biosynthesis by directly regulating SOS2 and P5CS1 homologs

New Phytol.

OsWRKY74, a WRKY transcription factor, modulates tolerance to phosphate starvation in rice

J. Exp. Bot.

Overexpression of a R1R2R3 MYB gene, OsMYB3R-2,Increases tolerance to Freezing,Drought,and salt stress in transgenic Arabidopsis

Plant Physiol.

Overexpression of AtWRKY30 transcription factor enhances heat and drought stress tolerance in wheat (Triticum aestivum L.)

Genes

Research article
A WRKY transcription factor, FtWRKY46, from Tartary buckwheat improves salt tolerance in transgenic Arabidopsis thaliana