Isolation and Characterization of a CBF Gene from Perennial Ryegrass (Lolium Perenne L.)

Maximum freezing tolerance of many temperate plant species is achieved after exposure to a period of non-freezing low temperatures, a phenomenon called “cold acclimation”. Multiple mechanisms appear to operate in conferring freezing tolerance in plants. The discovery of a class of transcription factor genes, CBF genes (C-repeat binding factor), in Arabidopsis demonstrated that CBF genes can serve as ‘Master switches’ to activate downstream cold-related (COR) genes during cold-acclimation (Liu et al., 1998). They act by binding to the core sequence (CCGAC) which is present in COR genes and thus activate the expression of COR genes and enhance freezing tolerance. The components of this cold acclimation pathway are conserved across a number of plant species including both eudicot and monocot species (Jaglo et al., 2001). Perennial ryegrass (L. perenne L.) is an important turf and forage grass but it lacks adequate winter hardiness which is a limiting factor for its adaptation to the northern regions of the US. Development of improved germplasm with enhanced winter hardiness would be highly desirable. The objective of this research was to isolate and characterize CBF gene(s) in perennial ryegrass and to determine the genomic location and the function of the CBF gene(s)