| Abstract Detail
Secondary Metabolism - Afternoon Mazourek, Michael [1], Stewart, Charles [2], Stellari, Giulia [2], Jahn, Molly [3]. Linking Genetic Diversity with Chemical Diversity using Genomic Resources in Capsicum. ONE of the unique attributes of Capsicum that distinguishes this genus among the Solanaceae is the production of capsaicinoids, the alkaloids that are responsible for the pungency of hot peppers. Beyond being used as a spice, capsaicinoids are used as analgesics and exhibit a number of other applications because they are ligands for TRPV1, a transmembrane receptor that modulates many signal transduction pathways throughout the body. Chemical differences among capsaicinoids confer different organoleptic properties to specific analogs, and we hypothesize that this chemical diversity also influences other relevant physiological responses. To elucidate the processes that account for the production and chemical diversity of capsaicinoids in hot peppers, we have used a multidisciplinary approach that links the genetic diversity of Capsicum to the chemical diversity of capsaicinoids by harnessing genomic tools initially developed in model species. This approach has yielded a number of new findings. First, we have isolated the gene that is responsible for all known non-pungency mutations in pepper and have shown it to be associated with both structural and regulatory functions. Second, we have identified a naturally occurring mutant that affects which capsaicinoids are produced, specifically the presence or absence of trans-desaturation in the acyl moiety. The mutant shows monogenic recessive inheritance and cosegregates with a homolog of ketoacyl synthase (Kas). Third, we have produced C. pubescens lines that stably accumulate rare or novel capsaicinoids as the dominant analogs. These novel capsaicinoid profiles appear to be under genetic control and are not influenced significantly by environment, as is total capsaicinoid accumulation. Finally, we have revised the model of capsaicinoid biosynthesis to reflect the current knowledge of the relevant biochemical pathways, the diversity of capsaicinoids and have subsequently cloned associated candidate genes.
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1 - Cornell University, Plant Biology, 306 Bradfield Hall, Ithaca, NY, 14853, USA
2 - Cornell University, Plant Biology, Ithaca, NY, 14853, USA
3 - Cornell University, Department of Plant Breeding and Genetics, Ithaca, NY, 14853, USA
Keywords:
capsaicin
Capsicum
phenylpropanoid
fatty acid
Pepper.
Session: SAT10-7
Location: Hall of Ideas Room F/Monona Terrace
Date: Wednesday, July 26th, 2006
Time: 5:00 PM
Abstract ID:229 |
