The role of Arabidopsis genes involved in abiotic (osmotic, oxidative and gravitropic) stress response regulation

Abstract

The warming of overall climate requires to breed plant cultivars tolerant to extreme osmotic tolerance, e.g. to high salt concentration in order to improve their chance to survive deleterious effects of abiotic stress conditions. Our initial aim is to isolate and characterize abiotic stress response regulatory genes arisen from Arabidopsis thaliana which is known as a model species for such investigations in higher plant. For this reason, a Ser/Thr protein kinase, the CRK5 was chosen. The CRK5 protein kinase is partly functionally characterized exhibiting a role in the regulation of gravitropic responses of Arabidopsis thaliana roots (Rigó et al., 2013). The CRK5 is a plasma membrane associated kinase that forms U-shaped patterns facing outer lateral walls of root epidermis cells. The CRK5 phosphorylates the hydrophilic loop of the auxin efflux transporter PIN2 in vitro. Thus, delayed gravitropic response of crk5 mutant reflects defective phosphorylation of PIN2 and deceleration of its brefeldin sensitive membrane recycling. Recently, we have been investigating the regulatory role of CRK5 protein kinase under osmotic (salt) and oxidative (hydrogen peroxide) stresses. The aim was to gather additional information regarding its role in the regulation of responses to either high salinity or oxidative stress, and consequently, regarding the impact on the auxin biosynthesis, transport and signaling. CRK protein kinase is hypothesized to be involved in the regulation of the effect of reactive oxygen species (ROS, e.g. hydrogen peroxide)