Abstract
As temperature decreases, cold-hardy plants acquire freezing tolerance gradually. Freezing tolerance can be induced in bromegrass (Bromus inermis Leyss) suspension cultures by exposure to low temperature or by exogenous application of abscisic acid (ABA). To understand the mechanisms of freezing tolerance in bromegrass, we analyzed the genes responsive to low temperature and ABA using rice cDNA microarray. Previously, we cloned a chitinase gene induced by cold and analyzed activities of the gene products expressed in E. coli.
We performed Northern blot analysis of this gene using total RNA extracted from bromegrass cells under various stresses. We found that the expression pattern differed considerably from those of other chitinase genes. To determine functions of the cold-induced chitinase, we constructed transgenic plants in an attempt to identify the activities and contribution of this gene to freezing tolerance.
