1a. Objectives (from AD-416)
To continue research to identify differentially expressed genes in the ornamental plant Petunia, floricultural crops and, from this information, to develop promoters that regulate specific genes involved in floral senescence and plant nutrition. To use genetics/genomics research to enhance traits in floriculture crops that address consumer preferences, such as floral fragrance.
1b. Approach (from AD-416)
Develop a coordinated research effort to isolate and sequence promoter elements in floricultural crops, to analyze expression of these genes using macro- or micro-array analysis, to identify genes with specific expression characteristics associated with tissue and physiological states, and to verify promoter function of specific genes using transgenic Petunia as the model.
3. Progress Report
This project is related to Objective 3a: Identify sources of plant resistance to Asian Citrus Psyllid (ACP) in citrus germplasm and 3b: Develop novel control methods based on disrupting key processes in pest biology. In the past year we finalized the addition of a wealth of new DNA sequence data through joint 454 sequencing efforts with European collaborators (Radboud University, NL; University of Verona, IT). One study elucidated the function of one transcription factor as having a fundamental role in the regulation of floral volatile benzenoid/phenylpropanoid (FVBP)induction by way of controlling anthesis or flower opening. This function was shown to be conserved in Solenaceae species and suggested to be conserved among most angiosperms. A second study illustrated that another transcription factor is required for the fine-tune regulation of a primary metabolic node controlling carbon flux from benzenoid production to phenylpropanoid production and again, this function is conserved throughout most angiosperms. The final manuscript was an invited review that details the specific transcriptional regulation imparted upon the FVBP gene network and possible biological reasons for such specific regulation. We have also isolated several new genes with putative involvement in direct biosynthesis of floral volatile synthesis pathway intermediates. We have made RNA inhibition constructs for most all of these genes, and are currently analyzing these plants with reduced expression. Progress was monitored through biannual meetings at the U.S. Horticultural Reserach Laboratory (USHRL)and through routine phone conference calls and emails.