Molecular characterization of soybean GmDjpl encoding a type III J-protein induced by abiotic stress

摘要

Heat stress severely affects plant growth and development causing crop loss worldwide. Classical type I DnaJ proteins (also called as J-proteins, J-domain proteins or HSP40 proteins) function as molecular co-chaperones for the HSP70 proteins. In thisstudy, we have cloned and characterized a novel gene GmDjpl (Glycine max DnaJ protein 1) encoding a type HI J-protein of which function has not been identified in plant. Deduced amino acid sequences of GmDjpl show the highest homology with a J-protein from Medicago truncatula legume plant (83 %) and with Arabidopsis thaliana type HI J-class proteins, at-DJC53 (77 %) and atDjC32 (50 %). DNA blot analysis revealed that GmDjpl exists as a 2-copy gene in soybean genome. GmDjpl mRNA was induced by a broad spectrum of abiotic stresses, including wounding, heat-shock, dehydration, cold or high-salinity stress, suggesting its role in the signaling events in the abiotic stress-related defense response. Subcellular localization studies demonstrated that the GmDjpl-GFP fusion protein was localized in the nucleus. Differential RNA expression of GmDjpl by heat-shock stress inspired us to test heat-shock tolerance of GmDjpl'm E. coli. Heterologous expression of GmDjpl conferred tolerance to high temperature stressin E. coli. This report provides strong evidence that GmDjpl may play a critical role during heat-shock stress in cell.