Towards functional characterisation of the members of theR2R3‐MYBgene family fromArabidopsis thaliana

Abstract

SummaryTranscription factors containing a conserved DNA-binding domain similar to that of the proto-oncogene c-myb have been identified in nearly all eukaryotes. MYB-related proteins from plants generally contain two related helix-turnhelix motifs, the R2 and R3 repeats. It was estimated that Arabidopsis thaliana contains more than 100 R2R3-MYB genes. The few cases where functional data are available suggest an important role of these genes in the regulation of secondary metabolism, the control of cell shape, disease resistance, and hormone responses. To determine the full regulatory potential of this large family of regulatory genes, a systematic search for the function of all genes of this family was initiated. Sequence data for more than 90 different A. thaliana R2R3-MYB genes have been obtained. Sequence comparison revealed conserved amino acid motifs shared by subgroups of R2R3-MYB genes in addition to the characteristic DNA-binding domain. No significant clustering of the genes was detected, although they are not uniformly distributed throughout the A. thaliana genome.

An R2R3-type transcription factor gene AtMYB59 regulates root growth and cell cycle progression in Arabidopsis

“…The first MYB gene identified in plants was C1 from maize, which is involved in anthocyanin biosynthesis [1]. Since then, several MYB genes have been isolated [2][3][4][5]. Recently, Chen et al [6] found 198 MYB genes from Arabidopsis and 183 from rice.…”

“…MYB proteins play important roles in multiple aspects of plant growth and development [2][3][4][5]. Several MYB proteins may be involved in secondary metabolism [7][8][9].…”

Quadruple 9-mer-Based Protein Binding Microarray Analysis Confirms AACnG as the Consensus Nucleotide Sequence Sufficient for the Specific Binding of AtMYB44

“…The AtMYB44 gene is upregulated by a variety of hormone treatments, abiotic stresses and microbial infections (Jung et al, 2010;Kranz et al, 1998;Yanhui et al, 2006). AtMYB44 regulates diverse cellular responses mediated by abscisic acid (Jung et al, 2008), jasmonate (Jung et al, 2010) and ethylene (Liu et al, 2010;Lü et al, 2011).…”

“…Among 198 genes in the MYB superfamily, a total of 126 R2R3 MYB-encoding genes have been identified in the Arabidopsis genome, making it one of the largest transcription factor groups in this plant (Yanhui et al, 2006). Extensive functional analyses using large-scale insertional mutagenesis (Meissner et al, 1999;Stracke et al, 2001) and expression profiling (Kranz et al, 1998;Yanhui et al, 2006) have been performed to characterize R2R3 MYB proteins in Arabidopsis. In parallel, the roles of individual R2R3 MYB proteins in diverse plant processes have been explored, including hormonal signaling, cellcycle control, stress responses, secondary metabolism, cellular morphogenesis and meristem formation (Das et al, 2012;Jin and Martin, 1999;Martin and Paz-Ares, 1997).…”

“…The Arabidopsis R2R3-type MYB transcription factors have been categorized into subgroups on the basis of conserved amino acid sequence motifs present in the carboxy-terminal to the MYB domain (Kranz et al, 1998). For instance, members of subgroup 22, including AtMYB44, AtMYB70, AtMYB73 and AtMYB77, share two conserved motifs: TGLYMSPxSP (motif 22.1) and GxFMxVVQEMIxxEVRSYM (motif 22.2) (Stracke et al, 2001).…”