Basic helix-loop-helices (bHLHs) are present in all eukaryotes and form one of the largest families of transcription factors (TFs) found in plants. bHLHs function as transcriptional activators and/or repressors of genes involved in key processes involved in plant growth and development in interaction with the environment (e.g., stomata and root hair development, iron homeostasis, and response to heat and shade). Recent studies have improved our understanding of the functioning of bHLH TFs in complex regulatory networks where a series of post-translational modifications (PTMs) have critical roles in regulating their subcellular localization, DNA-binding capacity, transcriptional activity, and/or stability (e.g., protein–protein interactions, phosphorylation, ubiquitination, and sumoylation).
The HD-Zip transcription factor family is a kind of special protein in plant, playing crucial roles in plant development processes and abiotic stresses response. The protein family includes a highly conserved homeodomain(HD) and a leucine zipper domain(LZ), forming a special structural model. The HD-Zip transcription factor family, including 63 members, can be classified into 4 subfamilies HD-Zip Ⅰ, HD-Zip Ⅱ, HD-Zip Ⅲ and HD-Zip Ⅳ. .
The MADS-box gene family is one of the largest families in plants and plays an important roles in floral development. The MADS-box family includes the SRF-like domain and K-box domain.
V-myb avian myoblast virus oncogene homolog (MYB) is a class of transcription factors discovered in recent years that are related to regulating physiological processes such as plant growth and development, physiological metabolism, cell morphology and pattern formation. It is widely present in plants and is also one of the largest transcription families in plants. MYB transcription factors play an important role in plant metabolism and regulation. MYB transcription factors have multiple biological functions and are widely involved in the growth and development of plant roots, stems, leaves, and flowers. At the same time, the MYB gene family also responds to abiotic stress processes such as drought, salinity, and cold damage. In addition, MYB transcription factors are closely related to the quality of certain economic crops.
NAC(NAM, ATAF1/2, CUC2)proteins are the superfamily of plant-specific transcription that are present in a wide range of species. Most of NAC proteins harbor a highly conserved DNA binding domain at the N-terminus consisting of approximately 150 amino acids and a flexible C-terminal domain being essential for transcriptional regulation. The NAC family members have been found to function in various processes including growth, development and stress response network; therefore, NAC transcription factors are continuously concerned. In recent years, especially in the past five years, groundbreaking discoveries in the functional research of NAC family members have achieved.
