Microbial ACC-deaminase biotechnology: Perspectives and applications in stress agriculture

Abstract

Ethylene regulates several physiological processes in plants; however, enhanced ethylene concentration has drastic effects on plants. Enhanced ethylene biosynthesis is associated with a number of environmental stresses. For sustainable plant growth, removal of this negative impact of ethylene is essential. Ethylene is produced by the conversion of 1-aminocyclopropane-1-carboxylic acid (ACC) in plants and its synthesis can be checked by ethylene inhibitors. Since there are environmental concerns about chemical inhibitors, suppression in ethylene biosynthesis can be achieved biologically through the action of rhizobacteria that can degrade the ethylene precursor ACC through their enzyme ACC-deaminase. In this chapter, the drastic effects of environmental stresses on plant growth, with a special reference to ethylene evolution, are discussed. Special attention is paid to the mechanisms used by plant growth promoting rhizobacteria (PGPR) containing ACC-deaminase to facilitate plant growth. Finally, the examples of plant growth promotion by inoculation with PGPR strains containing ACC-deaminase under different stresses are reviewed and discussed.