Gibberellin biosynthesis in maize. Metabolic studies with GA{sub 15}, GA{sub 24}, GA{sub 25}, GA{sub 7}, and 2,3-dehydro-GA{sub 9}

Journal Article · Mon Nov 01 04:00:00 EST 1999 · Plant Physiology (Bethesda)

DOI:https://doi.org/10.1104/pp.121.3.1037· OSTI ID:20006203

Davis, G; Kobayashi, Masatomo; Phinney, B O; Lange, T; Croker, S J; Gaskin, P; MacMillan, J

[17-{sup 14}C]-Labeled GA{sub 15}, GA{sub 24}, GA{sub 25}, GA{sub 7}, and 2,3-dehydro-GA{sub 9} were separately injected into normal, dwarf-1 (d1), and dwarf-5 (d5) seedlings of maize (Zea mays L.). Purified radioactive metabolites from the plant tissues were identified by sull-scan gas chromatography-mass spectrometry and Kovats retention index data. The metabolites from GA{sub 15} were GA{sub 44}, GA{sub 19}, GA{sub 20}, GA{sub 113}, and GA{sub 15}-15,16-ene (artifact?). GA{sub 24} was metabolized to GA{sub 19}, GA{sub 20}, and GA{sub 17}. The metabolites from GA{sub 25} were GA{sub 17}, GA{sub 25} 16{alpha},17-H{sub 2}-17-OH, and HO-GA{sub 25} (hydroxyl position not determined). GA{sub 7} was metabolized to GA{sub 30}, GA{sub 3}, isoGA{sub 3} (artifact?), and trace amounts of GA{sub 7}-diene-diacid (artifact?). 2,3-Dehydro-GA{sub 9} was metabolized to GA{sub 5}, GA{sub 7} (trace amounts), 2,3-dehydro-GA{sub 10} (artifact?), GA{sub 31}, and GA{sub 62}. Their results provide additional in vivo evidence of a metabolic grid in maize (i.e., pathway convergence). The grid connects members of a putative, non-early 3,130hydroxylation branch pathway to the corresponding members of the previously documented early 13-hydroxylation branch pathway. The inability to detect the sequence GA{sub 12}{r{underscore}arrow} GA{sub 15} {r{underscore}arrow} GA{sub 24} {r{underscore}arrow} GA{sub 9} indicates that the non-early 3,13-hydroxylation pathway probably plays a minor role in the origin of bioactive gibberellins in maize.

• Research Organization: Univ. of California, Los Angeles, CA (US)
• Sponsoring Organization: National Science Foundation; US Department of Energy
• DOE Contract Number: FG03-90ER20016
• OSTI ID: 20006203
• Journal Information: Plant Physiology (Bethesda), Journal Name: Plant Physiology (Bethesda) Journal Issue: 3 Vol. 121; ISSN 0032-0889; ISSN PLPHAY
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
BIOLOGICAL PATHWAYS
BIOSYNTHESIS
GIBBERELLIC ACID
MAIZE
METABOLISM