Bacterial δ-aminolevulinic acid synthase activity is not essential for leghemoglobin formation in the soybean/ Bradyrhizobium japonicum symbiosis
- 1 March 1986
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 83 (6), 1837-1841
- https://doi.org/10.1073/pnas.83.6.1837
Abstract
Previous studies of legume nodules have indicated that formation of the heme moiety of leghemoglobin is a function of the bacterial symbiont. We now show that a hemA mutant of Bradyrhizobium japonicum that cannot carry out the first step in heme biosynthesis forms fully effective nodules on soybeans. The bacterial mutant strain was constructed by first isolating the wild-type hemA gene encoding .delta.-aminolevulinic acid synthase (EC 2.3.1.37) from a cosmid library, using a fragment of the Rhizobium meliloti hemA gene as a hybridization probe. A deletion of the hemA gene region, generated in vitro, then was used to construct the analogous chromosomal mutation by gene-directed mutagenesis. The mutant strain had no .delta.-aminolevulinic acid synthase activity and was unable to grow in minimal medium unless .delta.-aminolevulinic acid was added. Despite its auxotrophy, the mutant strain incited nodules that appeared normal, contained heme, and were capable of high levels of acetylene reduction. These results rule out bacterial .delta.-aminolevulinic acid synthase activity as the exclusive source of .delta.-aminolevulinic acid for heme formation in soybean nodules.This publication has 28 references indexed in Scilit:
- Broad host range DNA cloning system for gram-negative bacteria: construction of a gene bank of Rhizobium meliloti.Proceedings of the National Academy of Sciences, 1980
- Differentiation of Rhizobium japonicum strain derivatives by antibiotic sensitivity patterns, lectin binding, and utilization of biochemicalsCanadian Journal of Microbiology, 1980
- REGULATION OF INITIATION OF DNA REPLICATIONAnnual Review of Genetics, 1979
- The effect of ammonium nitrate on the synthesis of nitrogenase and the concentration of leghemoglobin in pea root nodules induced by Rhizobium leguminosarumBiochimica et Biophysica Acta (BBA) - General Subjects, 1978
- Hemes, Chlorophylls, and Related Compounds: Biosynthesis and Metabolic RegulationPublished by Wiley ,1978
- Heme Synthesis in Soybean Root NodulesPlant Physiology, 1977
- Regulation of nitrogen fixation by Rhizobia export of fixed N2 as NH4+Biochimica et Biophysica Acta (BBA) - General Subjects, 1976
- Haem Biosynthesis from [14C]- -Aminolaevulinic Acid in Laboratory-grown and Root Nodule Rhizobium lupiniJournal of General Microbiology, 1971
- The site of heme synthesis in soybean root nodulesBiochimica et Biophysica Acta (BBA) - General Subjects, 1969
- A complementation analysis of the restriction and modification of DNA in Escherichia coliJournal of Molecular Biology, 1969