Plant Growth Promoting Rhizobacteria Improving the Legume–Rhizobia Symbiosis

Abstract

The legume-rhizobia symbiosis is considered the most important nitrogen fixing interaction from an agricultural point of view. However, biotic and abiotic factors can modify critical parameters of both the legume and the rhizobia. These changes may consist in marked differences in the molecular dialogue, consequently reducing the symbiotic effectiveness. Therefore, optimal performance of the N-fixing symbiosis will be guaranteed by selection of both symbiotic partners for adaptation to the target environment. The symbiotic process can be negatively affected by many other rhizosphere interactions, resulting in important ecological, economic and nutritional losses. The employment (utilization, application) of agricultural techniques that are friendly with the environment, based on the use of plant growth promoting rhizobacteria (PGPR), can increase the efficiency of the symbiotic process. The use of these beneficial microorganisms could reduce the use of polluting chemicals allowing sustainable agriculture. Co-inoculations of appropriate rhizobia together with PGPR would increase significantly the crop yield by different mechanisms. The negative effects of environmental stresses on the legume-rhizobia symbiosis could be significantly diminished by co-inoculation of rhizobia and PGPRs.The legume-rhizobia symbiosis is considered the most important nitrogen fixing interaction from an agricultural point of view. However, biotic and abiotic factors can modify critical parameters of both the legume and the rhizobia. These changes may consist in marked differences in the molecular dialogue, consequently reducing the symbiotic effectiveness. Therefore, optimal performance of the N-fixing symbiosis will be guaranteed by selection of both symbiotic partners for adaptation to the target environment. The symbiotic process can be negatively affected by many other rhizosphere interactions, resulting in important ecological, economic and nutritional losses. The employment (utilization, application) of agricultural techniques that are friendly with the environment, based on the use of plant growth promoting rhizobacteria (PGPR), can increase the efficiency of the symbiotic process. The use of these beneficial microorganisms could reduce the use of polluting chemicals allowing sustainable agriculture. Co-inoculations of appropriate rhizobia together with PGPR would increase significantly the crop yield by different mechanisms. The negative effects of environmental stresses on the legume-rhizobia symbiosis could be significantly diminished by co-inoculation of rhizobia and PGPRs.