ARS | Publication request: GENETIC CONTROL OF MAYSIN AND APIMAYSIN SYNTHESIS IN MAIZE SILKS

Submitted to: Plant and Animal Genome VX Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: January 16, 1997
Publication Date: N/A

Technical Abstract: The flavonoid pathway of maize, Zea mays L., offers an excellent system for investigating the quantitative effects of individual genes and their interactions and interpreting the results in terms of pathway functions. We used quantitative trait locus (QTL) methodology to analyze the genetic control of concentrations of the insect-resistance factors maysin and apimaysin in maize silks. Maysin is a C-glycosyl flavone with hydroxyl groups at the 3' and 4' positions of the B-ring, while apimaysin is identical except for a single hydroxyl group at the 4' position. Analysis of variance of an F2 population derived from the cross GT114 (low apimaysin) x NC7A (high apimaysin) indicated a major effect (R**2=32.3%) on apimaysin concentration near the pr1 locus, which encodes a flavonoid-3'-hydroxylase, but only a minor effect of that region (R**2=3.3%) on maysin level. Conversely, the wx1 region of chromosome 9S had a strong effect (R**2=21.8%) on maysin level, but no significant effect on apimaysin concentration. These results suggest that mono- and di-hydroxy intermediates are channeled separately through sections of the pathway. Comparison of results from this population with those from two previously analyzed populations revealed major effects on maysin concentration and identical gene action (dominant for low maysin) in the same region of chromosome 9S in each case.