Identification of Norway Spruce MYB-bHLH-WDR Transcription Factor Complex Members Linked to Regulation of the Flavonoid Pathway.
Transcription factors (TFs) forming MYB-bHLH-WDR complexes are known to regulate the biosynthesis of specialized metabolites in angiosperms through an intricate network. These specialized metabolites participate in a wide range of biological processes including plant growth, development, reproduction as well as in plant immunity. Studying the regulation of their biosynthesis is thus essential. While MYB (TFs) have been previously shown to control specialized metabolism (SM) in gymnosperms, the identity of their partners, in particular bHLH or WDR members, has not yet been revealed. To gain knowledge about MYB-bHLH-WDR transcription factor complexes in gymnosperms and their regulation of SW, we identified two bHLH homologs ofAtTT8, six homologs of the MYB transcription factorAtTT2 and one WDR ortholog ofAtTTG1 in Norway spruce. We investigated the expression levels of these genes in diverse tissues and upon treatments with various stimuli including methyl-salicylate, methyl-jasmonate, wounding or fungal inoculation. In addition, we also identified protein-protein interactions among different homologs of MYB, bHLH and WDR. Finally, we generated transgenic spruce cell lines overexpressing four of the Norway spruceAtTT2 homologs and observed differential regulation of genes in the flavonoid pathway and flavonoid contents.
Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences Uppsala, Sweden.
Miguel
M
Nemesio-Gorriz
Department of Biology, University of Alabama at Birmingham Birmingham, AL, USA.
Peter B
PB
Blair
Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences Uppsala, Sweden.
Kerstin
K
Dalman
Department of Microbiology, Forestry and Agricultural Biotechnology Institute, University of Pretoria Pretoria, South Africa.
Almuth
A
Hammerbacher
Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences Uppsala, Sweden.
Jenny
J
Arnerup
Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences Uppsala, Sweden.
Jan
J
Stenlid
Department of Biology, University of Alabama at Birmingham Birmingham, AL, USA.
Shahid M
SM
Mukhtar
Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences Uppsala, Sweden.
Malin
M
Elfstrand
MYB; Picea; TT2; TT8; TTG1; flavonoid; yeast two-hybrid