IDENTIFICATION OF CHILLING-RESPONSIVE PROTEINS FROM FLORAL BUDS OF BLUEBERRY

Changes in gene expression were examined in floral buds of a dormant w oody perennial, blueberry (Vaccinium, section Cyanococcus), in respons e to chilling unit accumulation. The concentration of 65, 60, and 14 k Da polypeptides increased in response to chilling under field conditio ns and with storage at 4-7 degrees C. Levels of the polypeptides incre ased most dramatically during the first 300 h of chilling and decrease d to the initial levels with the resumption of growth. The pIs, determ ined by isoelectric focusing of bud proteins, were 7.5-8.0 for the 65 and 60 kDa polypeptides and 8.5 for the 14 kDa polypeptide. Purificati on of the 65 and 60 kDa polypeptides followed by amino acid sequence a nalysis of selected peptide fragments revealed similarities in amino a cid composition between these polypeptides and dehydrins. Antiserum, r aised against the lysine rich consensus sequence EKKGIMDKIKEKLPG of de hydrins, crossreacted to all three of the chilling-responsive polypept ides of blueberry. Thus, the accumulation of dehydrin-like proteins in response to chilling was demonstrated in a woody perennial.