|Guill, Katherine - Kate|
Submitted to: Plant and Animal Genome VX Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 1/13/2001
Publication Date: 1/13/2001
Citation: SZALMA, S.J., MCMULLEN, M.D., SNOOK, M.E., HOUCHINS, K.E., BUSHMAN, B.S. CHALCONE SYNTHASE LOCI AND BIOCHEMICAL PATHWAY INTERACTIONS IN MAIZE. PLANT AND ANIMAL GENOME. 2001. ABSTRACT P. 173. Interpretive Summary:
Technical Abstract: The C-glycosyl flavone maysin is an important part of corn earworm (Helicoverpa zea L.)(CEW) resistance in maize (Zea mays L.) silks. Chlorogenic acid, a product of the phenylpropanoid pathway, has also been implicated in CEW antibiosis. The transistion from the 9-carbon phenylpropanoid to the 15-carbon flavonoid pathway represents a potentially yimportant regulation point in C-glycosyl flavone biosynthesis. The enzyme chalcone synthase catalyzes this step and is represented by a set of duplicate loci in maize, colorless2 (c2) and white pollen 1 (whp1). Our goal was to investigate the role of chalcone synthase in flavone biosyntheseis using three related F2 populations segregating for both structural and regulatory loci. Results from statistical and quantitative trait loci analyses: 1) Support earlier findings of the requirement of a functional pericarp color (p1) allele for C-glycosyl flavone biosynthesis. 2) Demonstrate that variation at the c2 region on chromosome 4 influences both maysin and chlorogenic acid levels in silks. 3) Reveal a dosage-dependent relationship between c2 and whp1 in which the whp1 region on chromosome 2 acts cooperatively with functional c2 to increase flavones, andpPartially compensates for the absence of c2. These results demonstrate that flavonoid and phenylpropanoid biosynthesis are not independent and that chalcone synthase function is a regulatory focal point of substrate flow in these metabolic pathways, because the c2 and p1 regions influence endproduct accumulation in both pathways.