Abstract: Basic helix-loop-helix proteins (bHLHs) are found throughout the eukaryotic kingdom, and constitute one of the largest families of plant transcription factors. They can regulate gene expression through interaction with specific motif in target genes. Phylogenetic analysis indicates that plant bHLHs are monophyletic. bHLHs are necessary for plant normal growth and development, and play important roles in abiotic-stress responses. However, we know little about their origins, structures, and functions due to the large quantities and complexity of plant bHLH family. This paper reviews on the evolution, structure characteristics, biological function of plant bHLHs, especially their functions in adapting to abiotic-stress tolerance, so as to provide a theoretical reference for further research on the function of plant bHLH transcription factors.

Key words: bHLHs, structural features, biological function