Abstract
RECEPTOR-LIKE PROTEIN KINASE1, RPK1, a protein localized to the plasma membrane, functions as a regulator of abscisic acid (ABA) signaling in Arabidopsis. We investigated the effect of RPK1 disruption and overproduction on plant responses to drought stress. The transgenic plants that overexpress RPK1 protein showed increased ABA sensitivity in root growth and stomatal closure and less transpirational water loss, and increased tolerance to drought stress. The microarray analysis of RPK1 transgenic plants revealed the enhanced expression of several stress-responsive genes and H2O2-responsive genes. The results suggested that the overproduction of RPK1 enhances ABA and drought stress signaling pathway. Furthermore, RPK1-overexpressing transgenic plants increased tolerance to oxidative stress with ABA-pretreatment. These data suggest that RPK1 overproduction also controls reactive oxygen species (ROS) homeostasis and enhances both water and oxidative stress and results in increased tolerance to these stresses in Arabidopsis.
