Factors Impacting Rhizobium-legume Symbiotic Nitrogen Fixation with the Physiological and Genetic Responses to Overcome the Adverse Conditions: A Review

Symbiotic N2 fixation is essential for the plant’s growth because it can fix reactive nitrogen compounds in soil. However, all steps of this process be hampered by several biotic and abiotic environmental factors. This study mainly focused on discussing impacts 12 major factors reviewing significant numbers research works. According to information from these works, we found some physiological genetic caused like plasmid deletion, genomic mismanagement, abnormal molecular signals, toxicity, deficiency minerals, deformation rhizobial cells, protein denaturation, nucleic acid damage, acetylene reduction nod limitation. Furthermore, expression heat or shock proteins, internal buffering, genes spanning, extracellular immobilization, periplasmic allocation, change lipopolysaccharides composition, intracellular accumulation inorganic organic solutes (Osmolyte) activation hydrogenase are shown both micro macro symbionts as a natural response adapt stress conditions. Though stress-tolerant strains HR-3, HR-6, HR-10, HR-12, acta, actP, exoR, lpiA, actR, actS phrR used sense external environment make signals gene transcription during adverse condition, application engineering should expanded more promote commercial inoculation production novel modified rhizobia legumes.