A petunia chorismate mutase specialized for the production of floral volatiles
Article first published online: 9 NOV 2009
© 2009 University of Florida. Journal compilation © 2009 Blackwell Publishing Ltd
The Plant Journal
Volume 61, Issue 1, pages 145–155, January 2010
How to Cite
Colquhoun, T. A., Schimmel, B. C.J., Kim, J. Y., Reinhardt, D., Cline, K. and Clark, D. G. (2010), A petunia chorismate mutase specialized for the production of floral volatiles. The Plant Journal, 61: 145–155. doi: 10.1111/j.1365-313X.2009.04042.x
- Issue published online: 18 DEC 2009
- Article first published online: 9 NOV 2009
- Received 19 June 2009; revised 15 September 2009; accepted 30 September 2009; published online 9 November 2009.
- Chorismate mutase;
In Petunia × hybrida cv. ‘Mitchell Diploid’ floral fragrance is comprised of 13 volatile benzenoids/phenylpropanoids derived from the aromatic amino acid phenylalanine. Several genes involved in the direct synthesis of individual floral volatile benzenoid/phenylpropanoid (FVBP) compounds, i.e. at the end of the pathway, have been isolated and characterized in petunia through reverse genetic and biochemical approaches. In an effort to understand the regulation of ‘upstream’ components in the FVBP system, we have cloned and characterized two CHORISMATE MUTASE (PhCM1 and PhCM2) cDNAs from petunia. PhCM1 has a transcript accumulation profile consistent with known FVBP genes, while PhCM2 showed a constitutive transcript accumulation profile. The plastid-localized PhCM1 is allosterically regulated by tryptophan but not phenylalanine or tyrosine. The total FVBP emission in PhCM1 RNAi knockdown petunias is reduced by approximately 60–70%, and total chorismate mutase activity in corolla tissue is reduced by 80–85% compared to control plants. These results show that PhCM1 is the principal CHORISMATE MUTASE responsible for the coupling of metabolites from the shikimate pathway to the synthesis of FVBPs in the corolla of Petunia × hybrida cv. ‘Mitchell Diploid’.