KuvausPeanut (Arachis hypogaea L.) is a tropical legume grown as an oilseed or food crop. Penut is the third most important leguminous crop by harvest area on a global basis, and China is a world leading producer of peanut. Peanut plants are mostly nodulated by bacterial strains belonging to the genus Bradyrhizobium. There are effective and ineffective symbioses between peanut and rhizobia; and that there are differences between rhizobial strains with respect to their competitiveness in plant nodulation. Moreover, there are differences even between varieties of peanut with respect to which rhizobial strain that is the most efficient microsymbiont. Despite extensive research efforts, the mechanisms are not well understood. Furthermore, many bradyrhizobia are involved in denitrification. The denitrification process requires four separate enzymatically catalysed reactions and are encoded by nap, nir, nor, and nos genes. Rhizobia that express N2O reductase (NosZ) can be used to mitigate emissions of the greenhouse gas N2O from agricultural fields cropped with legumes.
We tested the denitrification end-point products of 27 Bradyrhizobium strains. The results of which showed that seven strains were complete denitrifiers with strong N2O reduction, while the rest had truncated denitrification pathways with NO or N2O as end products. The N-fixation capacity of 34 bradyrhizobial strains was also tested on peanut plant in greenhouse. We also sequenced the genomes of 24 strains. The results of genomic analyses with respect to nitrogen fixation and denitrification of bradyrhizobia in peanut plant will be presented.
|20 elok. 2018
|13th European Nitrogen Fixation Conference