C-repeat binding transcription factors from Miscanthus × giganteus and their expression at a low temperature

Abstract

Giant miscanthus (Miscanthus × giganteus) is a valuable plant for bioenergy production and carbon sequestration in low-input agriculture. The newly establishing plantations of miscanthus are, however, at risk during the winter because of the small size of the clones and limited ability of reserves storage in the rhizomes. Increased freezing tolerance of both shoots and rhizomes of giant miscant has been observed after cold acclimation, when plants are exposed to low, non-freezing temperatures. In plants cold acclimation is under complex genetic control that is orchestrated by C-repeat binding factors (CBFs). The present paper aimed the identification and characterisation of CBF-family transcription factors in miscanthus and determined their expression profiles at a low temperature. Three miscanthus genes, homologous to sorghum and maize CBF-family genes were identified. However, only one – MgCBF6 was expressed in the cold-acclimated leaves of miscanthus with an expression profile typical of a CBF-family gene. The ability of miscanthus to cold acclimate was also confirmed using an electrolyte leakage test and survival count. An increase in freezing tolerance was observed both in leaves and rhizomes but only when an increase in the freezing tolerance of plasma membranes was considered. It may be concluded that CBF-induced gene expression pathway may be induced in M. × giganteus while this species use the dormancy strategy for overwintering.