Dehydrins (LTI29, LTI30, COR47) from Arabidopsis thaliana expressed in Escherichia coli protect Thylakoid membrane during freezing

As the name dehydrins implies, these proteins are typically expressed in response to dehydration which can be caused by drought, osmotic stress or freezing temperatures 1. In general, dehydrins occur in plants as multi-gene families. Four Arabidopsis dehydrins (LTI29, ERD14, COR47 and RAB18) have been tested for protection of thylakoid membranes during freeze thaw cycle in vitro. 2,3 Our firstly reported results show that dehydrins LTI29, ERD14, COR47 have cryoprotective activity while RAB18 did not protect the thylakoid membranes at low temperatures. The cryoprotective activity reached a maximum of 50% to 60% at protein concentration of 140-250 ?g/ml in the assay. A contribution of dehydrins to freezing tolerance in vivo is supported by the observation of Nylander et al. (2001)4 that LTI29 and COR47 are cold induced at mRNA and protein expression level.