Bacterial diversity in the root nodules and rhizosphere of chickpea (Cicer arietinum L.)

Chickpea (Cicer arietinum L.) is an annual winter legume and belongs to the family leguminasae, tribe Cicereae. Chickpea is a very good source of seed proteins and carbohydrates and the crop plays a significant role in agronomy by maintaining soil fertility due to its nitrogen fixing ability. Nitrogen and phosphorus are the most limiting nutrients for plant growth. Chickpea obtains a significant part of its nitrogen requirement from symbiotic association of Rhizobium inhabiting its root nodules. The microsymbiont (Rhizobium) reduces atmospheric nitrogen into plant-useable form ammonium. Free-living bacteria possessing plant-beneficial traits are also present in the rhizosphere. These bacteria, known as Plant Growth Promoting Rhizobacteria (PGPR), utilize one or more than one mechanisms for plant growth promotion, including nitrogen-fixation, P-solubilization and phytohormone production. Phosphate Solubilizing Bacteria (PSB) has been reported to increase P-concentration of soil by converting insoluble forms to soluble ones through the production of organic acids. Inoculation of soil with nitrogen fixing bacteria (free-living diazotrophs or symbiotic Rhizobium) and P-solubilizing bacteria is a promising approach that may alleviate the deficiency of nitrogen and phosphorus, respectivelyThis project is designed to compare diversity and population dynamics of bacteria in the rhizosphere of different varieties of chickpea. Different microbiological and DNA-based techniques will be employed for identification and enumeration of both culturable and non-culturable bacteria in the nodules and rhizosphere. Furthermore effects of co-inoculation of rhizobia with plant growth promoting rhizobacteria (PGPR) on growth of chickpea will be investigated.