Isoflavone levels in five soybean (Glycine max) genotypes are altered by phytochrome-mediated light treatments

Ara Kirakosyan, Peter Kaufman, Randall L. Nelson, Michael J. Kasperbauer, James A. Duke, Elisabeth Seymour, Chul Chang Soo, Sara Warber, Steven Bolling

Research output: Contribution to journalArticlepeer-review


The objective of the present study was to determine whether concentrations of different isoflavones (puerarin, genistein, genistin, daidzein, and daidzin) in shoots and roots of five selected soybean genotypes would respond the same or differently to red (650 nm peak transmittance) and far-red (750 nm peak transmittance) light treatments given under controlled environments. Levels of isoflavones (mg g-1 dry weight biomass) present in seeds, control roots, and shoots and 10 day light-treated seedlings (light, dark, red, and far-red wavelengths) of soybean (Glycine max) were determined by high-performance liquid chromatography analysis in comparison with known isoflavone standards. Seeds of the five soybean genotypes studied consistently stored most of their isoflavones as glucosyl conjugates (e.g., daidzin, genistin, and puerarin). For the five soybean genotypes, isoflavone levels were lower in the seeds as compared with roots plus shoots of control, time zero (first true leaf stage) seedlings. Following 10 days of the respective light treatments, we found that (i) isoflavone levels were enhanced in dark-grown plants over light-grown plants for three of the five genotypes (a new finding) and the reverse occurred for a single genotype (a typical response of legumes) and (ii) generally, far-red end of day (EOD) light treatment enhanced total isoflavone levels in roots plus shoots over red EOD light treatment. Results from the present study show that phytochrome does appear to play a role in regulating isoflavone levels in developing soybean seedlings and that this influence by red/far-red-mediated phytochrome reactions is strongly dependent on the genotypes selected for study.

Original languageEnglish (US)
Pages (from-to)54-58
Number of pages5
JournalJournal of Agricultural and Food Chemistry
Issue number1
StatePublished - Jan 11 2006
Externally publishedYes


  • Glycine max
  • Isoflavones
  • Red/far-red-mediated phytochrome reactions
  • Soybean

ASJC Scopus subject areas

  • Chemistry(all)
  • Agricultural and Biological Sciences(all)


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