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

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, was characterized from which was significantly upregulated in leaves by melatonin treatment during drought stress. The protein, belonging to group II of the WRKY family, was localized in the nucleus. The results indicated that overexpression of increased cotyledon greening and root elongation in transgenic lines under abscisic acid (ABA) treatment. Meanwhile, overexpression of 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 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.