A 27 kDa Rhododendron protein is associated with constitutive freezing tolerance and is related to the ABA / water deficit stress-inducible family of proteins

SummaryUp-regulation of specific genes (or accumulation of certain proteins) has been widely reported to be associated with increased freezing tolerance during cold acclimation in plants.In the present study, we focused on specific alterations in protein metabolism associated with constitutive freezing tolerance (i.e., the level of freezing tolerance in non-acclimated and de-acclimated states) in leaf tissues of Rhododendron, a broad–leaf evergreen species. Current-year leaves from three Rhododendron cvs. (‘Chionoides’, ‘Grumpy Yellow’ and ‘Vulcan’s Flame’) were collected for leaf freezing tolerance estimations, and protein extractions in non-acclimated, cold acclimated, and de-acclimated states. Two groups of containerised plants were used: 1) those exposed to natural field conditions during the course of the study; and 2) those maintained in environmentally-controlled growth chambers. Data indicated a distinct seasonal (group 1) or cyclical (group 2) pattern in leaf freezing tolerance in all cultivars i...