|Samac, Deborah - Debby|
Submitted to: International Congress on Molecular Plant-Microbe Interactions
Publication Type: Proceedings
Publication Acceptance Date: 10/1/2003
Publication Date: 6/7/2004
Citation: Fedorova, M., Denton, M., Schulze, J., Liu, J., Graham, M., Allan, D., Samac, D.A., Vance, C.P. 2004. Improving the legume-rhizobium symbiosis: can genomics help? In: Tikonovich, I., editor. Molecular Plant Microbe Interactions: New Bridges Between Past and Future. Kluwer Academic Publishers. p. 29-31.
Technical Abstract: Improvement of legume-Rhizobium symbiotic nitrogen (N2) fixation has been a long-term goal for agricultural science. Although programs aimed at improving symbiotic N2 fixation have incorporated approaches that involve both the microsymbiont and the legume host, limited success has been achieved. Selection for crop yield (biomass and N), harvest index, drought tolerance, and root architecture have been accompanied by higher total N2 fixation. In addition, microbiologists have been successful in selecting rhizobial strains for acid and salt tolerance, limited preference for nodulation, and improved inoculum, all resulting in greater N2 fixation. However, other than the seminal discoveries of rhizobial and plant genes involved in host-microbe signaling and early nodulation, we know little about the fundamental biochemical genetic mechanisms that have potential for increasing symbiotic N2 fixation. Recent advances in whole genome sequencing of rhizobia (described elsewhere in this Congress) and in plant functional genomics offer new strategies and targets for improving N2 fixation. Identification of plant genes affecting nodule initiation, nodule number, carbon and nitrogen interactions, Ca++-signaling host-microbe communication, improved nutrient acquisition, and plant defense response offer promise for enhancing symbiotic N2 fixation. However, this promise must involve a concerted interdisciplinary collaborative effort to be realized.