Watkinson, Jonathan I. , Winkel, Brenda S. J. .
Two CHS-interacting proteins, CyAP and ENTH-like, manipulate flavonoid production in response to auxin.
Growth and development of the plant root are essential for resource accumulation and are tightly regulated under changing environmental conditions to allow for efficient exploration of the substrate. Controls on growth allow the root to navigate around obstacles in the substrate, seek out water and nutrients, and avoid stressful conditions. It has been demonstrated that auxin is one of the main factors promoting changes in root growth, as it affects lateral root formation, root bending, and elongation growth. Flavonoids have been shown to affect auxin movement and this effect is seen at the level of the auxin efflux carrier. We recently found that in wild type plants, auxin could also stimulate a change in the ratio of flavonols in the root demonstrating that elevated auxin levels could modulate flavonoid production. In a yeast 2-hybrid screen we identified two potential protein-binding partners for the first enzyme of the flavonoid pathway, chalcone synthase. These proteins were identified as a cytosolic amino-peptidase (CyAP) and a protein with structural similarity to ENTH/VHS (ENTH-like) vesicular transport proteins. HPLC analysis of loss-of-function mutants for the genes encoding these proteins revealed that they had altered flavonol accumulation patterns in response to exogenous auxin when compared to WT. This result was confirmed by identification of flavonoids in vivo using DPBA staining. Root growth phenotypes of the mutants also appear to be different from WT and quantification of these differences is under way. The results suggest that ENTH-like and CyAP are key components of an auxin-flavonoid regulatory cycle.
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1 - Virginia Tech, Biological Sciences, 432 Latham Hall, Ag Quad Lane, Blacksburg, VA, 24061, USA
2 - Virginia Tech, Biological Sciences
Presentation Type: ASPB Minisymposium
Location: Continental C/Hilton
Date: Tuesday, July 10th, 2007
Time: 3:45 PM