Abstract
LEA proteins are highly hydrophilic with random structures and boiling-soluble characteristic. LEA proteins are known to accumulate highly during seed development or in tissues subjected to water-deficit. LEA proteins are thought to protect proteins and biomembranes under water-deficit conditions. We have identified a novel gene (WCI16) that is induced during cold acclimation in winter wheat. WCI16 did not show any sequence similarity to known classes of LEA proteins. Here, we show that WCI16 is a novel LEA-class protein that is involved in freezing tolerance. Recombinant WCI16 protein exhibited stability after boiling and in vitro cryoprotection of the freeze-labile enzyme, L-lactate dehydrogenase. 1H-NMR spectroscopy demonstrated that WCI16 has no hydrophobic region and forms random structures. These data suggested that WCI16 is a novel LEA-class protein. Recombinant WCI16 showed a double-stranded DNA binding activity, suggesting that WCI16 may protect DNA during environmental stresses. Overexpression of WCI16 in Arabidopsis conferred enhanced freezing tolerance over wild-type plants. These results indicated that WCI16 is involved in freezing tolerance in wheat.
