GSE108744
Transcriptomic dissection of Bradyrhizobium sp. strain ORS285 in symbiosis with Aeschynomene spp. inducing different bacteroid morphotypes with contrasted symbiotic efficiency
To circumvent the paucity of nitrogen sources in the soil Legume plants evolved a symbiotic interaction with nitrogen-fixing soil bacteria called rhizobia. During symbiosis, legumes form root organs called nodules, where bacteria are housed intracellularly and become active nitrogen fixers known as bacteroids. Depending on their host plant, bacteroids can adopt different morphotypes, being either unmodified (U), elongated (E) or spherical (S). E- and S-typr bacteroids undergo a terminal differentiation leading to irreversible morphological changes and DNA endoreduplication. Previous studies suggest that differentiated bacteroids display an increased symbiotic efficiency (E>U & S>U). In this study, we used a combination of Aeschynomene species inducing E- and S-type bacteroids in symbiosis with Bradyrhizobium sp. ORS285 to show that S- performed better than E-type bacteroids. Thus, we performed a transcriptomic analysis on E- and S-type bacteroids to identify the bacterial functions involved in each bacteroid type. Overall design: 3 conditions with 3 replicates each for each condition are analyzed. Two bacteroid conditions are compared : S-type bacteroids from A. indica nodules and E-type bacteroids from A. afraspera nodules, as well as a culture reference in rich medium