Dehydrins (LTI29, LTI30, and COR47) from Arabidopsis thaliana expressed in Escherichia coli protect thylakoid membranes 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) were tested for protection of thylakoid membranes during freeze thaw cycles in vitro.(2,3) The first reported results showed 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 50-60 % at a protein concentration of 140-250 mu g mL(-1) in the assay. A contribution of dehydrins to freezing tolerance in vivo is supported by the observation of Nylander et al.(4) that LTI29 and COR47 are cold induced at the mRNA and protein expression level.