Project R-2072

Identification and interaction of regulatory signal transduction pathways for adaptation of Rhizobium etli to non-growing conditions (Research)

Problem statement. Transition from fast-growing to non-growing conditions is pivotal in the life cycle of bacteria and essential for successful adaptation to diverse environments. In the life cycle of rhizobia, nitrogenfixing bacteria that elicit nodules on the roots of their leguminous host plants, these transitions are also crucial for adaptation to the host and survival in the soil. Important for nitrogen fixation are the differentiated bacteria inside the nodules, called bacteroids, which are non-growing and able to convert atmospheric nitrogen into ammonia (6, 22). Although some aspects of this bacteroid state have been extensively studied for many years, our global view on the way gene expression affects the differentiation process and the maintenance of the bacteroid state is still far from complete. Moreover, little is known about factors contributing to survival of rhizobia in free-living conditions. In this proposal, we intend to use a combination of expression profiling and phenotypical analysis to lay the foundation for a better understanding of the physiology of these different states and factors determining the transitions between physiological growing and non-growing states.

01 January 2010 - 31 December 2013