Functional characterization of Mitogen-Activated Protein Kinase Kinase (MAPKK) gene in Halophytic Salicornia europaea against salt stress

摘要

Mitogen-activated protein kinase (MAPK) cascade is conserved in eukaryotic organisms and plays a crucial role in signal transduction pathways, related to biotic and abiotic stress responses. The current study was aimed to target at cloning, structural and functional characterization of 1023bp SeMAPKK gene from Salicornia europaea. A SeMAPKK polypeptide chain of 340aa has eleven sub-domains, and S/TXXXXXS/T residues are conserved in the activation loop site between VII-VIII sub-domains. We identified TVY and MEY motifs at N-terminus and LKY, CAY and SKY motifs at C-terminus. Phylogenetic relationship revealed that SeMAPKK belongs to group D. Highest transcript signals were recorded in 0.75 M salt level stress, and down-regulation was observed in 1.0 M salt concentration. Overexpression of SeMAPKK gene in Arabidopsis conferred salt tolerance. Results of different salt tolerance assays revealed that transgenic plants were more tolerant and exhibited better growth than non-transgenic plants under salt stress.