A WRKY Transcription Factor, EjWRKY17, from Eriobotrya japonica Enhances Drought Tolerance in Transgenic Arabidopsis.

Dan Wang,Guolu Liang,Qiyang Chen,Weiwei Chen,Danlong Jing,Qigao Guo,Xinya Liu,Yan Xia

doi:10.3390/ijms22115593

Dan Wang, Guolu Liang + Show 6 more

Open Access

https://doi.org/10.3390/ijms22115593

Copy DOI

Abstract

The WRKY gene family, which is one of the largest transcription factor (TF) families, plays an important role in numerous aspects of plant growth and development, especially in various stress responses. However, the functional roles of the WRKY gene family in loquat are relatively unknown. In this study, a novel WRKY gene, EjWRKY17, was characterized from Eriobotrya japonica, which was significantly upregulated in leaves by melatonin treatment during drought stress. The EjWRKY17 protein, belonging to group II of the WRKY family, was localized in the nucleus. The results indicated that overexpression of EjWRKY17 increased cotyledon greening and root elongation in transgenic Arabidopsis lines under abscisic acid (ABA) treatment. Meanwhile, overexpression of EjWRKY17 led to enhanced drought tolerance in transgenic lines, which was supported by the lower water loss, limited electrolyte leakage, and lower levels of reactive oxygen species (ROS) and malondialdehyde (MDA). Further investigations showed that overexpression of EjWRKY17 promoted ABA-mediated stomatal closure and remarkably up-regulated ABA biosynthesis and stress-related gene expression in transgenic lines under drought stress. Overall, our findings reveal that EjWRKY17 possibly acts as a positive regulator in ABA-regulated drought tolerance.

Highlights

Plants often face multiple environmental constraints in terms of drought stress, temperature extremes, and salinity [1]
The results showed that the EjWRKY17 promoter contains one MYB binding site (MBS) involved in drought inducibility, one dehydration responsive element (DRE core), one defense and stress-responsive element (TC-rich repeats), and one element related to abscisic acid (ABA) responsiveness (ABRE), indicating that the EjWRKY17 might be involved in plants’ response to ABA-mediated drought stress
The results showed that the EjWRKY17 promoter contains one MYB binding site (MBS) involved in drought inducibility, one dehydration responsive element (DRE core), one defense and stressresponsive element (TC-rich repeats), and one element related to ABA responsiveness (ABRE), indicating that the EjWRKY17 might be involved in plants’ response to ABAmediated drought stress

Summary

Introduction

Plants often face multiple environmental constraints in terms of drought stress, temperature extremes, and salinity [1]. Water deficit is the main environmental factor severely constraining plant development and production. To adapt to these abiotic stresses, plants have evolved a series of intricate strategies at molecular, cellular, biochemical, and physiological levels [2,3], including stomatal movement, signal perception and transduction, the expression of stress-induced genes and activation of physiological and metabolic responses [4]. When plants are exposed to stress conditions, the transcription factors (TFs) act as central regulators by binding to specific cis-acting elements in the promoter regions to activate downstream gene expression, signal transduction, and adaptation networks [5]. As one of the largest transcription factor families, WRKY TFs are crucial regulatory proteins that respond to biotic and abiotic stresses and modulate physiological processes and development [10]. The modulation of the transcription of downstream target genes can be regulated by WRKY TFs via binding to the

Methods

Results

Discussion

Conclusion