Azospirillum brasilense and Azospirillum lipoferum Hydrolyze Conjugates of GA20 and Metabolize the Resultant Aglycones to GA1 in Seedlings of Rice Dwarf Mutants

CASSÁN FD; BOTTINI R; SCHNEIDER G; PICCOLI P

PLANT PHYSIOLOGY.

AMER SOC PLANT BIOLOGISTS

Año: 2001 vol. 125 p. 2053 - 2058

0032-0889

Azospirillum species are plant growth-promotive bacteria whose beneficial effects have been postulated to be partially due to production of phytohormones, including gibberellins (GAs). In this work, Azospirillum brasilense strain Cd and Azospirillum lipoferum strain USA 5b promoted sheath elongation growth of two single gene GA-deficient dwarf rice (Oryza sativa) mutants, dy and dx, when the inoculated seedlings were supplied with [17,17-2H2]GA20-glucosyl ester or [17,17- 2H2]GA20-glucosyl ether. Results of capillary gas chromatography-mass spectrometry analysis show that this growth was due primarily to release of the aglycone [17,17-2H2]GA20 and its subsequent 3-hydroxylation to [17,17-2H2]GA1 by the microorganism for the dy mutant, and by both the rice plant and microorganism for the dx mutant.