Project Number: 1907-21000-025-03
Project Type: Specific Cooperative Agreement

Start Date: Aug 01, 2005
End Date: Jul 31, 2010

Objective:
The objectives of this cooperative research project are to: 1) identify and functionally test genes that are important in the regulation of plant compounds with known or potential human health benefits. In doing so, we will identify candidates for manipulation through traditional breeding or transgenic strategies for enhancement of phytonutrients in plant-based foods and we will additionally develop basic knowledge regarding the genetic mechanisms underlying the synthesis and accumulation of target compounds. Specific compounds of interest under this project will be carotenoids, flavonoids, ascorbate, and folic acid; and 2) Use computational methods to identify cis- and trans-acting heavy metal responsive elements, as well as regulatory elements involved in the expression of aluminum tolerance genes.

Approach:
The general approach of this cooperative research project will entail utilization of emerging genomics technologies to identify genes related to phytonutrient accumulation in tomato with a small and complementary effort on melon. We will screen tomato and melon germplasm varying in target phytonutrient levels for genes whose expression is coordinated with changes in compound levels in the fruit of lines tested. Considerable germplasm appropriate for this study is available and already in hand in the ARS lab including lines that are mutated in genes regulating ripening (which impacts multiple compounds) and specific compounds in addition to wild-species introgression lines that we have already shown to be variable in all of our compounds of interest. Such a screen will yield large number of genes that will be screened initially via transient viral induced gene silencing (VIGS). Genes coming through the VIGS screens with an impact on phytonutrient levels will be used in development of a smaller number of stable transformants for comprehensive analysis. The ARS lab is proficient in tomato gene expression profiling using microarrays and creation and analysis of stable transformed tomato lines. Candidate melon genes will be initially analyzed (or their homologs) in tomato. The BTI cooperator¿s lab is proficient in creation and high through put transient expression of DNA constructs for testing function of candidate genes in tomato. The complementary skills and mutual interests of the ARS and BTI groups make this an ideal collaboration.