Investigation of myo-Inositol Catabolism in Rhizobium leguminosarum bv. viciae and Its Effect on Nodulation Competitiveness
Open Access
- 1 August 2001
- journal article
- research article
- Published by Scientific Societies in Molecular Plant-Microbe Interactions®
- Vol. 14 (8) , 1016-1025
- https://doi.org/10.1094/mpmi.2001.14.8.1016
Abstract
Three discrete loci required for growth on myo-inositol in Rhizobium leguminosarum bv. viciae have been characterized. Two of these are catabolic loci that code for malonate semialdehyde dehydrogenase (iolA) and malonate semialdehyde dehydrogenase (iolD). IolD is part of a possible operon, iolDEB, although the functions of IolE and IolB are unknown. The third locus, int, codes for an ABC transport system that is highly specific for myo-inositol. LacZ analysis showed that mutation of iolD, which codes for one of the last steps in the catabolic pathway, prevents increased transcription of the entire pathway. It is likely that the pathway is induced by an end product of catabolism rather than myo-inositol itself. Mutants in any of the loci nodulated peas (Pisum sativum) and vetch (Vicia sativa) at the same rate as the wild type. Acetylene reduction rates and plant dry weights also were the same in the mutants and wild type, indicating no defects in nitrogen fixation. When wild-type 3841 was coinoculated onto vetch plants with either catabolic mutant iolD (RU360) or iolA (RU361), however, >95% of the nodules were solely infected with the wild type. The competitive advantage of the wild type was unaffected, even when the mutants were at 100-fold excess. The myo-inositol transport mutant (RU1487), which grows slowly on myo-inositol, was only slightly less competitive than the wild type. The nodulation advantage of the wild type was not the result of superior growth in the rhizosphere. Instead, it appears that the wild type may displace the mutants early on in the infection and nodulation process, suggesting an important role for myo-inositol catabolism.Keywords
This publication has 28 references indexed in Scilit:
- Myo-inositol catabolism by Rhizobium in soil: HPLC and enzymatic studiesSoil Biology and Biochemistry, 2001
- A rhizopine strain of Sinorhizobium meliloti remains at a competitive nodulation advantage after an extended period in the soilSoil Biology and Biochemistry, 1999
- Plasmid-Encoded Catabolic Genes in Rhizobium leguminosarum bv. trifolii: Evidence for a Plant-Inducible Rhamnose Locus Involved in Competition for NodulationMolecular Plant-Microbe Interactions®, 1998
- Biotin and Other Water-Soluble Vitamins Are Key Growth Factors for Alfalfa Root Colonization byRhizobium meliioti1021Molecular Plant-Microbe Interactions®, 1996
- The distribution of inositol rhizopine genes in Rhizobium populationsSoil Biology and Biochemistry, 1995
- Identification of chromosomal genes located downstream of dctD that affect the requirement for calcium and the lipopolysaccharide layer of Rhizobium leguminosarumMicrobiology, 1994
- myo-Inositol catabolism and catabolite regulation in Rhizobium leguminosarum bv. viciaeMicrobiology, 1994
- Carbohydrate, Organic Acid, and Amino Acid Composition of Bacteroids and Cytosol from Soybean NodulesPlant Physiology, 1987
- Generalized Transduction in Rhizobium leguminosarumJournal of General Microbiology, 1979
- R Factor Transfer in Rhizobium leguminosarumMicrobiology, 1974