Evolutionary comparison of competitive protein-complex formation of MYB, bHLH, and WDR proteins in plants

Abstract

A protein complex consisting of a MYB, basic Helix-Loop-Helix, and a WDR protein, the MBW complex, regulates five traits, namely the production of anthocyanidin, proanthocyanidin, and seed-coat mucilage, and the development of trichomes and root hairs. For complexes involved in trichome and root hair development it has been shown that the interaction of two MBW proteins can be counteracted by the respective third protein (called competitive complex formation). We examined competitive complex formation for selected MBW proteins from Arabidopsis thaliana, Arabis alpina, Gossypium hirsutum, Petunia hybrida, and Zea mays. Quantitative analyses of the competitive binding of MYBs and WDRs to bHLHs were done by pull-down assays using ProtA- and luciferase-tagged proteins expressed in human HEC cells. We found that some bHLHs show competitive complex formation whilst others do not. Competitive complex formation strongly correlated with a phylogenetic tree constructed with the bHLH proteins under investigation, suggesting a functional relevance. We demonstrate that this different behavior can be explained by changes in one amino acid and that this position is functionally relevant in trichome development but not in anthocyanidin regulation.

Transcriptome and Flavonoids Metabolomic Analysis Identifies Regulatory Networks and Hub Genes in Black and White Fruits of Lycium ruthenicum Murray

“…Three proteins were identified cluster with anthocyanin regulators PhAN2 and PhPHZ (Petunia x hybrida), AtPAP1(Arabidopsis thaliana) (Borevitz et al, 2000;Albert et al, 2011). Meanwhile, we found that LrAN1b and LrJAF13 were clustered into two clades, namely TT8 and GL3 clades, as previously described (Zhang B. et al, 2019). LrAN1b belongs to the TT8 clade, most homologous with StbHLH (Solanum tuberosum) and PhAN1(Petunia x hybrida), while another LrJAF13 was clustered with NtJAF13a, NtJAF13a (Nicotiana tabacum) and PhJAF13 (Petunia x hybrida) (Quattrocchio et al, 1998).…”

Genome-wide survey of the bHLH super gene family in Brassica napus

“…Partially redundantly regulates anthocyanin biosynthesis, trichome and root hair development [27,28,35,54,55].…”

Genome-wide Survey of bHLH Super Gene Family in Brassica napus and Their Roles in Roots

“…In this complex, both the MYB and the WD40 proteins bind to the bHLH protein [35,47,48]. Moreover, this complex is proved to be conserved in plants during evolution [73,76,77], which regulates five processes, namely the production of anthocyanidin, proanthocyanidin, seed-coat mucilage, and trichomes and root hairs development [70]. For example, the roles of this complex in controlling the development of trichomes and root hairs are verified in many species, ranging from monocots (Z. mays) to dicots (Arabidopsis, Arabisalpina, Gossypium hirsutum and Petunia hybrida) [23,25,78].…”

“…For example, the roles of this complex in controlling the development of trichomes and root hairs are verified in many species, ranging from monocots (Z. mays) to dicots (Arabidopsis, Arabisalpina, Gossypium hirsutum and Petunia hybrida) [23,25,78]. And four residues of GL3 and EGL3 proteins are identified to be vital for the protein interaction, including Phe-177 of AtGL3, Pro-377 of AtGL3, Asp-477 of AtGL3 and Ser-589 of AtGL3 [70]. Similarly, these key residues are observed in BnbHLH orthologs as well (Additional file 1: Table S1), suggesting they may have the same/or similar roles in B. napus.…”