MYB Transcription Factors and Its Regulation in Secondary Cell Wall Formation and Lignin Biosynthesis during Xylem Development

Abstract

The secondary wall is the main part of wood and is composed of cellulose, xylan, lignin, and small amounts of structural proteins and enzymes. Lignin molecules can interact directly or indirectly with cellulose, xylan and other polysaccharide molecules in the cell wall, increasing the mechanical strength and hydrophobicity of plant cells and tissues and facilitating the long-distance transportation of water in plants. MYBs (v-myb avian myeloblastosis viral oncogene homolog) belong to one of the largest superfamilies of transcription factors, the members of which regulate secondary cell-wall formation by promoting/inhibiting the biosynthesis of lignin, cellulose, and xylan. Among them, MYB46 and MYB83, which comprise the second layer of the main switch of secondary cell-wall biosynthesis, coordinate upstream and downstream secondary wall synthesis-related transcription factors. In addition, MYB transcription factors other than MYB46/83, as well as noncoding RNAs, hormones, and other factors, interact with one another to regulate the biosynthesis of the secondary wall. Here, we discuss the biosynthesis of secondary wall, classification and functions of MYB transcription factors and their regulation of lignin polymerization and secondary cell-wall formation during wood formation.

Identification and Analysis of MYB Gene Family for Discovering Potential Regulators Responding to Abiotic Stresses in Curcuma wenyujin

“…The large size of MYB family reflects their importance and functional diversity in regulating plant physiological and biochemical processes. Previous studies depicted that MYBs are involved in plant development, cell shape and petal morphogenesis, cellular proliferation and differentiation, trichome development, phenylpropanoid metabolism, hormone responses, biotic and abiotic stress responses, etc ( Baillo et al, 2019 ; Cao et al, 2020 ; Wang et al, 2021 ; Xiao et al, 2021 ).…”

“…Drought, high salt, extreme temperatures, and other stresses all impact the yield and quality of C. wenyujin . The v-myb avian myeloblastosis viral oncogene homolog (MYB) superfamily is one of most significant transcription factor (TF) families in plants, which regulates plant growth, development, and a variety of physiological/biochemical processes ( Cao et al, 2020 ; Wang et al, 2021 ; Xiao et al, 2021 ).…”

“…The R2R3-MYB subfamilies from Arabidopsis thaliana and Oryza sativa , the model plants for dicotyledons and monocotyledons respectively, have been well identified and characterized ( Dubos et al, 2010 ; Katiyar et al, 2012 ). Many R2R3-MYBs were reported to regulate the primary and secondary metabolism, cell fate and identity, developmental processes, and response to biotic, and abiotic stresses ( Li X. et al, 2019 ; Nguyen et al, 2019 ; Cao et al, 2020 ; Xiao et al, 2021 ). For example, Arabidopsis MYB30 acts as a critical negative regulator promoting PIF4 and PIF5 protein accumulation in the light to regulate photomorphogenic development ( Yan et al, 2020 ).…”

Integrated Transcriptomic and Proteomic Analysis in the Roadmap of the Xylem Development Stage in Populus tomentosa

“…Secondary wall formation-related genes mainly comprise a series of NAM, ATAF1/2, and CUC2 (NAC) and v-myb avian myeloblastosis viral oncogene homolog (MYB) transcription factors (TFs) forming a hierarchical network that gradually regulates the synthesis of cellulose, hemicellulose, and lignin during secondary wall formation ( Nakano et al, 2015 ). Previous studies indicate that the biosynthesis of the xylem cell wall of Arabidopsis is mediated by a three-layer transcriptional regulation model ( Ko et al, 2014 ; Xiao et al, 2021 ). Recent studies have found a similar regulatory network in bananas, in which NAC and MYB TFs forming a complex transcriptional network that regulates secondary wall deposition ( Negi et al, 2017 , 2018 ).…”

Table_1.xls

“…Secondary wall formation-related genes mainly comprise a series of NAM, ATAF1/2, and CUC2 (NAC) and v-myb avian myeloblastosis viral oncogene homolog (MYB) transcription factors (TFs) forming a hierarchical network that gradually regulates the synthesis of cellulose, hemicellulose, and lignin during secondary wall formation (Nakano et al, 2015). Previous studies indicate that the biosynthesis of the xylem cell wall of Arabidopsis is mediated by a three-layer transcriptional regulation model (Ko et al, 2014;Xiao et al, 2021). Recent studies have found a similar regulatory network in bananas, in which NAC and MYB TFs forming a complex transcriptional network that regulates secondary wall deposition (Negi et al, 2017(Negi et al, , 2018.…”