Production of gibberellins and indole-3-acetic acid by Rhizobium phaseoli in relation to nodulation of Phaseolus vulgaris roots

Similar ranges of gibberellins (GAs) were detected by high-performance liquid chromatography (HPLC)-immunoassay procedures in ten cultures of wild-type and mutant strains of Rhizobium phaseoli. The major GAs excreted into the culture medium were GA1 and GA4. These identifications were confirmed by combined gas chromatographymass spectrometry. The HPLC-immunoassays also detected smaller amounts of G A 9 as well as GA2o-like compounds, the latter being present in some but not all cultures. In addition to GAs, all strains excreted indole-3-acetic acid (IAA) but there was no obvious relationship between the amounts of GA and IAA that accumulated. The Rhizobiurn strains studied included n o d and f i x mutants, making it unlikely that the IAAand GAbiosynthesis genes are closely linked to the genes for nodulation and nitrogen fixation. The HPLC-immunoassay analyses showed also that nodules and non-nodulated roots of Phaseolus vulgaris L. contained similar spectra of GAs to R. phaseoli culture media. The GA pools in roots and nodules were of similar size, indicating that Rhizobium does not make a major contribution to the GA content of the infected tissue.

[1]  MARGARETHA G. Mes,et al.  Influence of Gibberellic Acid and Photoperiod on the Growth, Flowering, Nodulation and Nitrogen Assimilation of Vicia villosa , 1959, Nature.

[2]  A. Crozier,et al.  Quantitative Analysis of Plant Hormones , 1980 .

[3]  C. Wheeler,et al.  Non-legume nodule systems. , 1980 .

[4]  J. Torrey,et al.  Identification of Cytokinins of Root Nodules of the Garden Pea, Pisum sativum L. , 1976, Plant physiology.

[5]  J. Shine,et al.  Mass Spectrometric Quantification of Indole-3-Acetic Acid in Rhizobium Culture Supernatants: Relation to Root Hair Curling and Nodule Initiation , 1982, Applied and environmental microbiology.

[6]  A. Crozier.  Aspects of the Metabolism and Physiology of Gibberellins , 1981 .

[7]  C. Wheeler,et al.  HORMONES IN PLANTS BEARING NITROGEN- FIXING ROOT NODULES: THE DISTRIBUTION OF CYTOKININS IN VICIA FABA L. , 1976 .

[8]  A. Galston,et al.  Inhibitory Effect of Gibberellins on Nodulization in Dwarf Beans, Phaseolus vulgaris , 1958, Nature.

[9]  S. Long,et al.  Induction of Rhizobium meliloti nodC expression by plant exudate requires nodD. , 1985, Proceedings of the National Academy of Sciences of the United States of America.

[10]  D. Blevins,et al.  Differences in Endogenous Levels of Gibberellin-Like Substances in Nodules of Phaseolus lunatus L. Plants Inoculated with Two Rhizobium Strains. , 1981, Plant physiology.

[11]  G. Sandberg,et al.  The biosynthesis of indole-3-acetic acid by Frankia , 1984 .

[12]  G. Sandberg,et al.  Effects of sodium diethyldithiocarbamate, solvent, temperature and plant extracts on the stability of indoles , 1986 .

[13]  H. Schlenk,et al.  Esterification of Fatty Acids with Diazomethane on a Small Scale , 1960 .

[14]  E. Weiler,et al.  Levels of indole-3-acetic acid in intact and decapitated coleoptiles as determined by a specific and highly sensitive solid-phase enzyme immunoassay , 1981, Planta.

[15]  J. Dullaart.  THE BIOPRODUCTION OF INDOLE-3-ACETIC ACID AND RELATED COMPOUNDS IN ROOT NODULES AND ROOTS OF LUPINUS LUTEUS L. AND BY ITS RHIZOBIAL SYMBIONT , 1970 .

[16]  N. J. Brewin,et al.  Growth regulators, Rhizobium and nodulation in peas , 1982, Planta.

[17]  J. Macmillan.  Hormonal regulation of development I. Molecular aspects of plant hormones. , 1980 .