Isolating rhizobacteria that improve salinity stress tolerance in plants which were watered with saline water
2Department of Environmental Hydrology and Microbiology, Ben Gurion University
In recent years climate change threatens food security and production. Farmers can no longer count on rain to irrigate their fields, and freshwater reservoirs are less available. In arid and semi-arid areas like Israel, a creative solution to this problem is irrigation with brackish water (400 to 4000 mg/liter of Chloride). However, such high concentrations of salts cause stress in the plant, with consequent decrease in crop quantity and quality.
Rhizobacteria are bacteria that grow around a plant root and in symbiosis with it. They can affect the plant`s health in various conditions, including salt stress. Ethylene is a gaseous hormone that regulated plant growth and development and serves as a key modulator between plant response to environmental stresses and normal growth. Our study goal was to find rhizobacteria that can interfere with ethylene, by degrading its precursor ACC (aminocyclopropane-1-carboxylic acid), into ammonia and α-Ketobutyric acid. Lessening the effects of ethylene will improve germination and growth while irrigating with brackish water.
Rhizobacteria were isolated from halophytes such as zugan (Zygophyllum) and maluach (Saltbushes). We grew them with ACC as the sole source of nitrogen and carbon. Success was evaluated by measuring ammonia and α-Ketobutyric acid concentrations. Our results showed increased ammonia concentration and biomass accumulation while the α-Ketobutyric acid amount did not change. To conclude: isolated rhizobacteria succeed in transforming ACC into ammonia and α-Ketobutyric acid.