PRJNA19575
A photosynthetic strain isolated from a Aeschynomene stem nodule
<b><i>Bradyrhizobium</i> sp. ORS278</b>. This strain was isolated from an <i>Aeschynomene</i> stem nodule and is photosynthetic, which is a rare trait in <i>Rhizobium</i> bacteria. These strains exhibit a photoheterotrophic and strictly aerobic photosynthesis. In culture, most stem isolates show the same pink coloration, while a few strains produce orange pigmentation. Pigment analyses showed that bacteriochlorophyll and spirilloxanthin, two pigments of the light harvesting system, are common to all of these photosynthetic <i>Bradyrhizobium</i> strains, whereas orange strains produce an additional bicyclic carotenoid, canthaxanthin (4,4'-diketo-beta-carotene). <i>Bradyrhizobium</i> sp. strain ORS278 produces the highest quantity of canthaxanthin of all tested photosynthetic bacteria; canthaxanthin represents 85% of its total carotenoid content.