Marine Algal-Derived Endophytic Bacteria: Induced Tolerance to Salinity Stress in Mexican Lime Seedlings

Bacterial endophytes grow symbiotically inside of plants, and improve the growth of their hosts. We investigated the effects of inoculating Macroalgae bacterial endophytes, introduced formerly by our group, Bacillus aquimaris strain OD۱۴, B. megaterium strain AM۲۵, B. zhangzhouensis strain Tv۹۱C, individually and in combination with each other on the reactive oxygen species (ROS) scavenging and antioxidant functions and growth characteristics in Mexican lime seedlings under salinity stress. To do so, Mexican lime (Citrus aurantifolia Swingle) seedlings were subjected to four salinity levels including ۰, ۲۰۰۰, ۴۰۰۰ and ۶۰۰۰ µs/cm, in present/absent of the bacterial endophytes. The results indicated that salinity stress significantly reduced growth, chlorophyll and carotenoid content of the plants lacking endophytes. Combinatory applications with bacterial endophytes significantly improved the above-mentioned parameters under salinity stress. Lipid peroxidation level were significantly reduced in the plants that inoculated with bacterial endophytes. Salinity stress significantly increased activities of ascorbate peroxidase (APX), superoxide dismutase (SOD), glutathione reductase (GR), peroxidase (POD) and catalase (CAT), in salinity conditions. Overall, bacterial endophytes inoculation improved salinity tolerance and reduced the accumulation of ROS by increasing their scavenging via improving the redox state glutathione and promotion of antioxidant enzymes activity.

کلیدواژه ها:

Bacterial endophytes ، Glutathione reductase ، mexican lime ، ROS ، Salinity stress