RcDhn5, a cold acclimation-responsive dehydrin from Rhododendron catawbiense rescues enzyme activity from dehydration effects in vitro and enhances freezing tolerance in RcDhn5-overexpressing Arabidopsis plants

摘要: Dehydrins (DHNs) are typically induced in response to abiotic stresses that impose cellular dehydration. As extracellular freezing results dehydration, accumulation of DHNs and development desiccation tolerance believed be key components the cold acclimation (CA) process. The present study shows RcDhn5, one from Rhododendron catawbiense leaf tissues, encodes an acidic, SK(2) type DHN is upregulated during seasonal CA downregulated spring deacclimation (DA). Data vitro partial water loss assays indicate purified RcDhn5 protects enzyme activity against a dehydration treatment this protection comparable with acidic SK(n) other species. To investigate contribution (FT), Arabidopsis plants overexpressing under control 35S promoter were generated. Transgenic exhibited improved 'constitutive' FT compared plants. Furthermore, small but significant improvement RcDhn5-overexpressing was observed after 12 h CA; however, gained capacity not sustained 6-day CA. Transcript profiles cold-regulated native (COR47, ERD10 ERD14) time-course suggests apparent lack cold-acclimated over wild-type controls might have been because dilution effect overproduction by strong CA-induced expression DHNs. This provides evidence contributes stress could be, part, its stress-protective ability.