Endophytes from African Rice ( L.) Efficiently Colonize Asian Rice ( L.) Stimulating the Activity of Its Antioxidant Enzymes and Increasing the Content of Nitrogen, Carbon, and Chlorophyll.

Bacterial endophytes support the adaptation of host plants to harsh environments. In this study, culturable bacterial endophytes were isolated from the African rice L., which is well-adapted to grow with poor external inputs in the tropical region of Mali. Among these, six N-fixer strains were used to inoculate RAM133 and the Asian rice L. cv. Baldo, selected for growth in temperate climates. The colonization efficiency and the N-fixing activity were evaluated and compared for the two rice varieties. -inoculated plants showed a fairly good colonization efficiency and nitrogenase activity. The inoculation of with the strains BDA134-6 and BDA59-3 led to the highest nitrogenase activity. In addition, the inoculation of 'Baldo' plants with the strain BDA59-3 led to a significant increase in nitrogen, carbon and chlorophyll content. Finally, 'Baldo' plants inoculated with BDA134-6 showed the induction of antioxidant enzymes activity and the maintenance of nitrogen-fixation under salt stress as compared to the unstressed controls. As these endophytes efficiently colonize high-yielding crop varieties grown in cold temperate climates, they become good candidates to promote their growth under unfavorable conditions.