Perspective of plant growth promoting rhizobacteria (PGPR) containing ACC deaminase in stress agriculture

Abstract

Ethylene is a gaseous plant growth hormone produced endogenously by almost all plants. It is also produced in soil through a variety of biotic and abiotic mechanisms, and plays a key role in inducing multifarious physiological changes in plants at molecular level. Apart from being a plant growth regulator, ethylene has also been established as a stress hormone. Under stress conditions like those generated by salinity, drought, waterlogging, heavy metals and pathogenicity, the endogenous production of ethylene is accelerated substantially which adversely affects the root growth and consequently the growth of the plant as a whole. Certain plant growth promoting rhizobacteria (PGPR) contain a vital enzyme, 1-aminocyclopropane-1-carboxylate (ACC) deaminase, which regulates ethylene production by metabolizing ACC (an immediate precursor of ethylene biosynthesis in higher plants) into alpha-ketobutyrate and ammonia. Inoculation with PGPR containing ACC deaminase activity could be helpful in sustaining plant growth and development under stress conditions by reducing stress-induced ethylene production. Lately, efforts have been made to introduce ACC deaminase genes into plants to regulate ethylene level in the plants for optimum growth, particularly under stressed conditions. In this review, the primary focus is on giving account of all aspects of PGPR containing ACC deaminase regarding alleviation of impact of both biotic and abiotic stresses onto plants and of recent trends in terms of introduction of ACC deaminase genes into plant and microbial species.

Agricultural uses of plant biostimulants

“…A wide range of soil microorganisms, including the fungus Penicillium citrinum (Honma 1993) produce the enzyme ACC deaminase that degrades ACC to α-ketobutyrate and ammonia (Blaha et al 2006;Chinnadurai et al 2009). Inoculation of diverse plant species with bacteria expressing ACC deaminase activity stimulates plant growth (Glick et al 2007;Saleem et al 2007). (Glick et al 1998) proposed a model to explain the role of bacterial ACC deaminase in plant growth promotion.…”

“…As a result, ACC levels in the plant are lowered and the ET content is reduced (Glick et al 1998). Once ET is reduced there is an increase in plant biomass (Contesto et al 2008;Saleem et al 2007). Bacteria with ACC deaminase activity have been extensively used for alleviating diverse stresses in plants.…”

“…Bacteria with ACC deaminase activity have been extensively used for alleviating diverse stresses in plants. By reducing the stress hormone ET, these bacteria are able to protect plants from the growth inhibition caused by ET under numerous stress conditions, such as flooding, toxic compounds (both organic compounds and heavy metals), high salt concentrations, drought, and pathogenic attack (Glick et al 2007;Saleem et al 2007). …”

Recent Application of Probiotics in Food and Agricultural Science

“…These microorganisms have fulfilled important functions for plant as they antagonize various plant pathogens, induce immunity, or promote growth [38][39][40]. The interaction between bacteria and fungi with their host plants has shown their ability to promote plant growth and to suppress plant pathogens in several studies [41][42][43][44].…”

Inducing salinity tolerance in chickpea (Cicer arietinum L.) by inoculation of 1-aminocyclopropane-1-carboxylic acid deaminase-containing Mesorhizobium strains

“…Salt stress also enhance ethylene (C 2 H 4 ) synthesis which in most of the cases acts as stress hormone in plant (Grichko and Glick, 2001;Arshad and Frankenberger, 2002). ACC deaminase enzyme lowers the level of C 2 H 4 in plants and it protects the plants from the deleterious effects of environmental stresses (Reed and Glick, 2005;Saleem et al, 2007;Aamir et al, 2013).…”