BWMK1 Responds to Multiple Environmental Stresses and Plant Hormones

Many plant mitogen-activated protein kinases (MAPKs) play an important role in regulating responses to both abiotic and biotic stresses. The first reported rice MARK gene BWMK1 is induced by both rice blast (Magnaporthe grlsea) infection and mechanical wounding. For further analysis of its response to other environmental cues and plant hormones, such as jasmonic acid (JA), salicylic acid (SA), and benzothiadiazole (BTH), the promoter of BWMK1 was fused with the coding region of the β-glucuronidase (GUS) reporter gene. Two promoter-GUS constructs with a 1.0- and 2.5-kb promoter fragment, respectively, were generated and transformed into the japonica rice cultivars TP309 and Zhonghua 11. Expression of GUS was induced in the transgenic lines by cold, drought, dark, and JA. However, light, SA, and BTH treatments suppressed GUS expression. These results demonstrate that BWMK1 is responsive to multiple abiotic stresses and plant hormones and may play a role in cross-talk between different signaling pathways.