Two Loci Exert Major Effects on Chlorogenic Acid Synthesis in Maize Silks

• Published in: Crop science Vol. 42; no. 5; pp. 1669 - 1678
• Main Authors: Bushman, Bradley S., Snook, Maurice E., Gerke, Justin P., Szalma, Stephen J., Berhow, Mark A., Houchins, Katherine E., McMullen, Michael D.
• Format: Journal Article
• Language: English
• Published: Madison Crop Science Society of America 01-09-2002; American Society of Agronomy
• Subjects: Agronomy. Soil science and plant productions; Bioflavonoids; Biological and medical sciences; Biosynthesis; Cellular biology; Classical and quantitative genetics. Population genetics. Molecular genetics; Corn; Crops; Flavones; Flavonoids; Fundamental and applied biological sciences. Psychology; Gene mapping; Generalities. Genetics. Plant material; Genetic aspects; Genetic regulation; Genetics; Genetics and breeding of economic plants; Molecular genetics; Molecules; Physiological aspects; Phytochemistry; United States; Allelism; Monocotyledones; Phenylpropanoid pathway; Flavones; Insecta; Biosynthesis; Metabolic pathway; Genetic determinism; Cereal crop; Pest; Gramineae; Helicoverpa zea; Insect resistance; Angiospermae; Genetic mapping; Zea mays; Chlorogenic acid; Quantitative trait loci; Phenol; Arthropoda; Lepidoptera; Pest resistance; Spermatophyta; Noctuidae; Invertebrata
• ISSN: 0011-183X; 1435-0653
• DOI: 10.2135/cropsci2002.1669

Chlorogenic acid (CGA) in maize (Zea mays L.) silks has been implicated in resistance to corn earworm (Helicoverpa zea Boddie) with a mechanism similar to the flavone, maysin. However, the genetic basis of CGA synthesis is poorly understood. Our goal was to identify candidate loci affecting the biosynthesis of CGA using quantitative trait locus (QTL) analyses on three F2 populations: (A619 × Mp708)F2, (A619 × Mo6)F2, and (Mo6 × Mp708)F2 Chlorogenic acid and flavone contents in silks were measured, linkage maps generated, and significant loci identified with composite interval mapping (CIM) and ANOVA multiple‐effects models for the three populations. Of the QTLs detected, two exerted major effects; one corresponding to the p1 locus, and the other a novel locus we named qtl2 The main effect of the functional allele at the p1 locus was to increase both CGA and flavones, while the positive allele at the qtl2 locus only increased CGA. An epistatic interaction between p1 and qtl2 alleles in the (A619 × Mo6)F2 population caused an increase in CGA with a concomitant decrease in flavones. The rare ability of Mo6 and Mp708 to synthesize CGA in excess of flavones is primarily a result from the effects at the qtl2 locus.