Project Number: 1275-21000-195-01
Project Type: Specific Cooperative Agreement

Start Date: Mar 01, 2005
End Date: Feb 28, 2010

Objective:
Determine the expression and control of structural and regulatory genes for anthocyanin coloration of leaves, flowers, and fruit in pepper. Develop selectable markers useful in breeding for tissue-specific anthocyanin accumulation.

Approach:
Published sequence data of the Petunia x hybrida An1, An2, An4 and An11 regulatory genes, and the various anthocyanin-related structural genes (Chs, Dfr, Dhr, An6, etc.) will be used to obtain cDNA or partial genomic DNA clones of >500bp by PCR, in order to study the expression of Capsicum genes and obtain selectable markers for these genes in pepper. We have already developed Capsicum PCR primers for Chs, Dfr and Ans. Expression of anthocyanin-related genes will be examined in pepper fruit, leaf and flower tissue in plants of varying genotype and pigmentation using viral-induced break and related to viral RNA distribution. HPLC profiling will be used to determine which pigments are reduced or increased in viral-induced color break. Gene expression of the affected steps will be examined, and comparisons made between the plant genes and viral sequences for localized homology that might cause silencing. Northern analysis and/or microarray analysis of mRNA extracted from the various tissues will be performed to determine whether the pattern of viral distribution coincides with changes in gene expression and the increase or decrease in anthocyanin concentrations in color break.