Identification and Characterization of Regulatory Pathways Controlling Dormancy Under Lower Temperature in Alfalfa ( L.).

Alfalfa ( L.), a kind of high-quality perennial legume forage, is widely distributed in the northern regions of China. In recent years, low temperatures have frequently occurred and limited alfalfa productivity and survival in early spring and late fall. However, the underlying molecular mechanisms of alfalfa response to cold tolerance are not well-documented. In this study, dormancy and non-dormancy alfalfa standard varieties were characterized under low-temperature stress. Our analysis revealed that plant height of the dormancy genotype was strongly inhibited by low temperature; flavonoids content, and higher expression of flavonoids biosynthesis genes (, and ) may play essential roles in response to low-temperature stress in dormancy genotype alfalfa. Further analyses revealed that receptor-like kinase family genes (such as , and ), RNA and protein synthesis genes (, and ), and proteasome degradation pathway genes (such as , and ) also highly upregulated and contributed to cold tolerance phenotype in dormancy genotype alfalfa. This will provide new insights into future studies for cold tolerance in alfalfa and offer new target genes for further functional characterization and genetic improvement of alfalfa.