Overexpression of a WRKY transcription factor McWRKY57-like from Mentha canadensis L. enhances drought tolerance in transgenic Arabidopsis

Abstract

AbstractBackgroundDrought has become a major environmental problem affecting crop production. Members of the WRKY family play important roles in plant development and stress responses. However, their roles in mint have been barely explored.ResultsIn this study, we isolated a drought-inducible geneMcWRKY57-likefrom mint and investigated its function. The gene encodes a group IIc WRKY transcription factor, McWRKY57-like, which is a nuclear protein with a highly conserved WRKY domain and a C2H2 zinc-finger structure, and has transcription factor activity. Its expression levels were examined in different tissues of mint and under the treatment of mannitol, NaCl, abscisic acid, and methyl jasmonate. We found thatMcWRKY57-likeoverexpression in Arabidopsis significantly increased drought tolerance. Further studies showed that under drought stress,McWRKY57-like-overexpressing plants had higher chlorophyll, soluble sugar, soluble protein, and proline contents but lower water loss rate and malondialdehyde content than wild-type plants. Moreover, the activities of antioxidant enzymes catalase, superoxide dismutase, and peroxidase were enhanced inMcWRKY57-liketransgenic plants. Furthermore, qRT-PCR analysis revealed that the drought-related genesAtRD29A,AtRD29B,AtRD20,AtRAB18,AtCOR15A,AtCOR15B,AtKIN2, andAtDREB1Awere upregulated inMcWRKY57-liketransgenic plants than in wild-type Arabidopsis under simulated drought conditions.ConclusionThese data demonstrated thatMcWRKY57-likeconferred drought tolerance in transgenic Arabidopsis by regulating plant growth, osmolyte accumulation and antioxidant enzyme activities, and the expression of stress-related genes. The study indicates thatMcWRKY57-likeplays a positive role in drought response in plants.