Perspectives of Rhizobacteria with ACC Deaminase Activity in Plant Growth Under Abiotic Stress

The abiotic and biotic stresses in the environment trigger the synthesis of ethylene, a gaseous plant hormone that leads to many physiological changes in plants that inhibit plant growth and development. Plant growth inhibition that accrues from the stress can be overcome to a large extent by lowering the amount of ethylene that is synthesized in response to stress by the application of ACC deaminase-producing bacteria. The plant growth-promoting bacteria also give other multifacet benefits as they promote plant growth through enhancing nutrient uptake and hormone production and acting as a biocontrol agent. The enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase present in bacterium cleaves ACC, the precursor of ethylene, and thereby lowers the ethylene level and facilitates plant growth. Plants respond similarly to ACC deaminase regardless of whether the enzyme is expressed in the roots of transgenic plants or as part of a root-associated bacterium. The role of growth-promoting bacteria is encouraging in this area. Thus overcoming stress responses in plants through ACC deaminase-producing bacteria has come up as an effective tool, when the agricultural practices worldwide are seeking a sustainable approach to the issues of food security under the changing climatic conditions. The present review discusses the role of ACC deaminase-producing bacteria in ameliorating the various abiotic stress responses in plants induced by ethylene.