An Arabidopsis homeodomain transcription factor gene, HOS9, mediates cold tolerance through a CBF-independent pathway

摘要: To investigate essential components mediating stress signaling in plants, we initiated a large-scale response screen using Arabidopsis plants carrying the firefly luciferase reporter gene under control of stress-responsive RD29A promoter. Here report identification and characterization mutant, hos9-1 (for high expression osmotically responsive genes), which construct was hyperactivated by low temperature, but not abscisic acid or salinity stress. The mutants grow more slowly, flower later, than do wild-type are sensitive to freezing, both before after acclimation, plants. HOS9 encodes putative homeodomain transcription factor that is localized nucleus. constitutively expressed further induced cold Cold treatment increased level transcripts endogenous RD29A, some other genes, higher However, C repeat/dehydration element-binding (CBF) genes mediate part acclimation did have their altered mutation. Correspondingly, microarray analysis showed none affected mutation controlled CBF family. Together, these results suggest important for plant growth development, freezing tolerance, affecting activity independent pathway.