Modulation of Quorum Sensing in Acyl-homoserine Lactone-Producing or -Degrading Tobacco Plants Leads to Alteration of Induced Systemic Resistance Elicited by the Rhizobacterium Serratia marcescens 90-166

Abstract

Numerous root-associated bacteria (rhizobacteria) are known to elicit induced systemic resistance (ISR) in plants. Bacterial cell-density-dependent quorum sensing (QS) is thought to be important for ISR. Here, we investigated the role of QS in the ISR elicited by the rhizobacterium, Serratia marcescens strain 90−166, in tobacco. Since S. marcescens 90−166 produces at least three QS signals, QS-mediated ISR in strain 90−166 has been difficult to understand. Therefore, we investigated the ISR capacity of two transgenic tobacco (Nicotiana tabacum) plants that contained either bacterial acylhomoserine lactone-producing (AHL) or -degrading (AiiA) genes in conjunction with S. marcescens 90−166 to induce resistance against bacterial and viral pathogens. Root application of S. marcescens 90−166 increased ISR to the bacterial pathogens, Pectobacterium carotovorum subsp. carotovorum and Pseudomonas syringae pv. tabaci, in AHL plants and decreased ISR in AiiA plants. In contrast, ISR to Cucumber mosaic virus was reduced in AHL plants treated with S. marcescens 90−166 but enhanced in AiiA plants. Taken together, these data indicate that QS-dependent ISR is elicited by S. marcescens 90−166 in a pathogen-dependent manner. This study provides insight into QS-dependent ISR in tobacco elicited by S. marcescens 90−166.

Bacterial quorum sensing compounds are important modulators of microbe-plant interactions

“…On the other hand, tobacco plants have been engineered to produce short- and long-side chain AHL-compounds which could be detected in substantial amounts at leaf and root surfaces as well as in soil (Scott et al, 2006 ). Constitutive expression of QS genes in transgenic tobacco plants leads to alteration in induced systemic resistance elicited by the rhizobacterium Serratia marcescens 90–166 (Ryu et al, 2013 ). Furthermore, transgenic tomato plants engineered to produce different AHL-compounds were demonstrated to alter the activity of plant growth promoting rhizobacteria and resulted, e.g., in increased salt tolerance (Barriuso et al, 2008 ).…”

Growth-Stimulatory Effect of Quorum Sensing Signal Molecule N-Acyl-Homoserine Lactone-Producing Multi-Trait Aeromonas spp. on Wheat Genotypes Under Salt Stress

“…For instance, if SAL-17 produces a wide variety of AHLs and higher IAA than SAL-21 and SAL-12, the response toward SAL-17 single inoculation and a mix inoculation (SAL-17 + SAL-21) was more pronounced on different biochemical, physiological, and growth parameters of wheat. AHLs directly or indirectly induce stress resistance in plants through QS-mediated production of metabolites (Ryu et al, 2013). It has been reported that inoculation of 3-oxo-C12-HSL-producing bacterial strains induce salt stress tolerance, metabolic regulation, and phytohormone response in tomato and Medicago truncatula (Mathesius et al, 2003;Barriuso et al, 2008).…”

Genomic analysis and plant growth-promoting potential of a Serratia marcescens isolated from food

“…PGPR producing IAA may enhance the resistance against pathogens. The ISR has already been shown to be effective in rhizobacterium S. marcescens acting as a PGPR (Ryu et al, 2013).…”