Oxidation of indole-3-acetic acid and oxindole-3-acetic acid to 2,3-dihydro-7-hydroxy-2-oxo-1H indole-3-acetic acid-7'-O-beta-D-glucopyranoside in Zea mays seedlings.
Radiolabeled oxindole-3-acetic acid was metabolized by roots, shoots, and caryopses of dark grown Zea mays seedlings to 2,3-dihydro-7-hydroxy-2-oxo-1H indole-3-acetic acid-7'-O-beta-D-glycopyranoside with the simpler name of 7-hydroxyoxindole-3-acetic acid-glucoside.  This compound was also formed from labeled indole-3-acetic acid supplied to intact seedlings and root segments.  The glucoside of 7-hydroxyoxindole-3-acetic acid was also isolated as an endogenous compound in the caryopses and shoots of 4-day-old seedlings.  It accumulates to a level of 4.8 nanomoles per plant in the kernel, more than 10 times the amount of oxindole-3-acetic acid.  In the shoot it is present at levels comparable to that of oxindole-3-acetic acid and indole-3-acetic acid (62 picomoles per shoot).  We conclude that 7-hydroxyoxindole-3-acetic acid-glucoside is a natural metabolite of indole-3-acetic acid in Z. mays seedlings.  From the data presented in this paper and in previous work, we propose the following route as the principal catabolic pathway for indole-3-acetic acid in Zea seedlings:  Indole-3-acetic acid --> Oxindole-3-acetic acid --> 7-Hydroxyoxindole-3-acetic acid --> 7-Hydroxyoxindole-3-acetic acid-glucoside.
Nonhebel
H M
HM
Department of Botany and Plant Pathology, Michigan State University, East Lansing 48824-1312, USA.
Bandurski
R S
RS
D006897:Hydroxyindoleacetic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism*; D010084:Oxidation-Reduction; D018517:Plant Roots / Q000378:metabolism; D018520:Plant Shoots / Q000378:metabolism; D003313:Zea mays / Q000378:metabolism*
D007210:Indoleacetic Acids; D006897:Hydroxyindoleacetic Acid; C030737:indoleacetic acid; C046777:7-hydroxy-2-oxoindole-3-acetic acid 7'-O-glucopyranoside