Isolation of Atriplex nummularia-associated halotolerant bacteria and bioprospecting by nitrogen fixing bacteria in saline-sodic soil

摘要

The plant-associated habitat is a dynamic environment exploited by a wide variety of bacteria. These bacteria can contribute to the health, growth and development of plants by different mechanisms. Atriplex plants cultivated in saline sodic soils stimulated a bioprospection of bactcria-Atriplex interaction mechanisms. Therefore, the aim of this work was to study the interaction Atriplex nummularia- halotolerant bacteria and bioprospect nitrogen fixing bacteria. Leaf and root endophytic bacteria and bacteria from rhizosphere, cultivated soil and uncultivated soil were isolated using 10% TSA plus 50 g l~(-1) of NaCl. Furthermore, the screening for nitrogen fixing bacteria was evaluated by the ability to grow in semi-solid nitrogen-free NFb medium. Thenumbers of total cultivable halotolerant bacteria were significant between leaves, roots and rhizoplane of A. nummularia plants. The NFb medium methodology revealed that 56% of analyzed halotolerant isolates were able to grow in nitrogen free medium. The percentage of nitrogen fixing bacteria was higher for the bacteria in close interaction with the host plant than for the less related niches. The results from this study indicated that Atriplex nummularia-associated halotolerant bacteria are able to fix nitrogen and were found at higher percentage in close interaction with the host plant.