Succinate transport is not essential for symbiotic nitrogen fixation by Sinorhizobium meliloti nor Rhizobium leguminosarum.

Succinate transport is not essential for symbiotic nitrogen fixation by Sinorhizobium meliloti nor Rhizobium leguminosarum. Appl Environ Microbiol. 2017 Sep 15;: Authors: Mitsch MJ, diCenzo GC, Cowie A, Finan TM Abstract Symbiotic nitrogen fixation (SNF) is an energetically expensive process performed by bacteria during endosymbiotic relationships with plants. The bacteria require the plant to provide a carbon source for generation of reductant to power SNF. While C4-dicarboxylates (succinate, fumarate, malate) appear to be the primary, if not sole, carbon source provided to the bacteria, the contribution of each C4-dicarboxylate is not known. We address this issue using a genetic and systems-level analyses. Expression of a malate specific transporter (MaeP) in Sinorhizobium meliloti Rm1021 dct mutants unable to transport C4-dicarboxylates resulted in malate import rates up to 30% that of wild type. This was sufficient to support SNF with Medicago sativa, with acetylene reduction rates up to 50% those of plants inoculated with wild type S. melilotiRhizobium leguminosarum bv. viciae 3841 dct mutants unable to transport C4-dicarboxylates but expressing the maeP transporter had strong symbiotic properties, with Pisum sativum plants inoculated with these strains appearing similar to plants inoculated with wild type R. leguminosarum This was despite malate transport rates by the mutant bacteroids being 10% those of the wild type. A RNA-se...
Source: Applied and Environmental Microbiology - Category: Microbiology Authors: Tags: Appl Environ Microbiol Source Type: research