The Use of ACC deaminase to increase the tolerance of plants to various phytopathogens

Abstract

The phytohormone ethylene is an important mediator of stress responses and plant growth and development. Many plant growth-promoting bacteria, including those that live in the rhizosphere (PGPB and PGPR, respectively), produce the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase which can cleave ACC, the immediate precursor of ethylene in plants, to α-ketobutyrate and ammonia, thereby lowering ethylene levels. These result in longer roots and less inhibition of ethylene-sensitive plant growth following environmental- or pathogen-induced stress. In this review, we have summarized and discussed the data demonstrating an additional important characteristic of ACC deaminase-producing PGPRs, which is the ability to serve as biocontrol agents of several bacterial and fungal plant pathogens. Therefore, ACC deaminase-containing bacteria may be viewed as general biocontrol agents of plant pathogens. Moreover, plants transformed with exogenous bacterial ACC deaminase genes are less susceptible to a range of diseases. Notwithstanding the promising results obtained so far, further research is needed to elucidate the detailed mechanisms used by beneficial plant-associated ACC deaminase-producing bacteria to facilitate biocontrol activity against plant pathogenic microorganisms.