Overexpression of GmWRKY17, a class IIb WRKY transcription factor from Glycine max, enhances drought tolerance in Arabidopsis plants

Abstract

Drought is one of the abiotic stresses affecting agricultural production. WRKY transcription factors have important functions in response to drought. However, functions of only a few WRKY transcription factors are understood in soybean. Here, GmWRKY17 was cloned from soybean and shown to bind the W-box sequence. GmWRKY17 was tissue-specific and induced by drought. Overexpression of GmWRKY17 was found to decrease abscisic acid (ABA) sensitivity and increase drought tolerance in Arabidopsis thaliana. GmWRKY17 improved germination rate, leaf opening and greening, root length and chlorophyll content under osmotic stress and drought. GmWRKY17 reduced malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) levels under drought. GmWRKY17 promoted stomatal closure after treatment with 10% polyethylene glycol 6000 (PEG6000). Overexpression of GmWRKY17 increased superoxide dismutase (SOD) activity and catalase (CAT) activity, and GmWRKY17 promoted the expression of AtSOD1 and AtCAT1 under drought. Moreover, GmWRKY17 increased proline content and enhanced the expression of AtP5CS1, and GmWRKY17 up-regulated stress-related genes under drought stress. All results showed that overexpression of GmWRKY17 improved drought tolerance, and GmWRKY17 may regulate drought stress by enhancing antioxidant activity and upregulating stress-related genes in Arabidopsis thaliana.