| Title: | PhMYB4 fine-tunes the floral volatile signature of Petunia x hybrida through PhC4H |
| Author(s): | Colquhoun TA; Kim JY; Wedde AE; Levin LA; Schmitt KC; Schuurink RC; Clark DG; |
| Address: | "Department of Environmental Horticulture, University of Florida, 1523 Fifield Hall, Gainesville, Florida 32611, USA" |
| ISSN/ISBN: | 1460-2431 (Electronic) 0022-0957 (Print) 0022-0957 (Linking) |
| Abstract: | "In Petunia x hybrida cv 'Mitchell Diploid' (MD), floral volatile benzenoid/phenylpropanoid (FVBP) biosynthesis is controlled spatially, developmentally, and daily at molecular, metabolic, and biochemical levels. Multiple genes have been shown to encode proteins that either directly catalyse a biochemical reaction yielding FVBP compounds or are involved in metabolite flux prior to the formation of FVBP compounds. It was hypothesized that multiple transcription factors are involved in the precise regulation of all necessary genes, resulting in the specific volatile signature of MD flowers. After acquiring all available petunia transcript sequences with homology to Arabidopsis thaliana R2R3-MYB transcription factors, PhMYB4 (named for its close identity to AtMYB4) was identified, cloned, and characterized. PhMYB4 transcripts accumulate to relatively high levels in floral tissues at anthesis and throughout open flower stages, which coincides with the spatial and developmental distribution of FVBP production and emission. Upon RNAi suppression of PhMYB4 (ir-PhMYB4) both petunia cinnamate-4-hydroxylase (PhC4H1 and PhC4H2) gene transcript levels were significantly increased. In addition, ir-PhMYB4 plants emit higher levels of FVBP compounds derived from p-coumaric acid (isoeugenol and eugenol) compared with MD. Together, these results indicate that PhMYB4 functions in the repression of C4H transcription, indirectly controlling the balance of FVBP production in petunia floral tissue (i.e. fine-tunes)" |
| Keywords: | "Amino Acid Sequence Eugenol/analogs & derivatives/metabolism Flowers/chemistry/genetics/growth & development/*metabolism *Gene Expression Regulation, Plant Molecular Sequence Data Petunia/chemistry/genetics/growth & development/*metabolism Plant Proteins/;" |
| Notes: | "MedlineColquhoun, Thomas A Kim, Joo Young Wedde, Ashlyn E Levin, Laura A Schmitt, Kyle C Schuurink, Robert C Clark, David G eng Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. England 2010/11/12 J Exp Bot. 2011 Jan; 62(3):1133-43. doi: 10.1093/jxb/erq342. Epub 2010 Nov 10" |
