N-3-oxo-hexanoyl-homoserine lactone, a bacterial quorum sensing signal, enhances salt tolerance in Arabidopsis and wheat

Abstract

Background: N-acyl-homoserine lactones (AHLs) are the quorum sensing (QS) signal molecules to coordinate the collective behavior in a population in Gram-negative bacteria. Recent evidences demonstrate their roles in plant growth and defense responses. Results: In present study, we show that the treatment of plant roots with N-3-oxo-hexanoyl-homoserine lactone (3OC6-HSL), one molecule of AHLs family, resulted in enhanced salt tolerance in Arabidopsis and wheat. We found that the growth inhibition phenotype including root length, shoot length and fresh weight were significantly improved by 3OC6-HSL under salt stress condition. The physiological and biochemical analysis revealed that the contents of chlorophyll and proline were increased and the contents of MDA and Na + and Na + /K + ratios were decreased after 3OC6-HSL treatment in Arabidopsis and wheat under salt stress condition. Molecular analysis showed that 3OC6-HSL significantly upregulated the expression of salt-responsive genes including ABA-dependent osmotic stress responsive genes COR15a, RD22, ADH and P5CS1, ABA-independent gene ERD1, and ion-homeostasis regulation genes SOS1, SOS2 and SOS3 in Arabidopsis under salt stress condition. Conclusions: These results indicated that 3OC6-HSL enhanced plant salt tolerance and ABA-dependent and ABAindependent signal pathways and SOS signaling might be involved in the induction of salt resistance by 3OC6-HSL in plants. Our data provide a new insight into the plant-microbe inter-communication.

Halo-tolerant plant growth promoting rhizobacteria for improving productivity and remediation of saline soils

“…3OC6-HSL was found to be increasing the root and shoot length, plant biomass, proline and chlorophyll content and reduced MDA (malondialdehyde) and Na + levels. The molecular mechanism revealed that 3OC6-HSL was up-regulating expression of salinity-tolerance genes including COR15a, RD22, ADH and P5CS1 (ABA-dependent osmotic stress regulating genes) , ERD1 (ABA-independent pant signaling gene), and SOS1, SOS2 and SOS3 (salinity responsive genes) in both the plants [124] . Correlatively, red rice plants inoculated with Gluconacetobacter diazotrophicus under drought stress showed synthesis of AHL molecules by LuxI proteins (autoinducer proteins) which enhanced tolerance in plants through IST [125] .…”

Impact of Quorum Sensing Molecules on Plant Growth and Immune System

“…Yet another discovery is very interesting in this context, the resistance to abiotic stresses (high salt concentrations) was enhanced after the treatment with oxo-C6-HSL (Barriuso et al, 2008;Zhao et al, 2020). Even though the exact mechanism of AHL-induced salt tolerance is not yet known, the possibility to modulate the plant tolerance to abiotic stresses like salt or drought using AHL is very interesting.…”

“…These molecules are usually used by Gram-negative bacteria in their intra- and inter-population communication and have well-documented impact on Arabidopsis and other plants ( Hartmann et al, 2014 ; Schikora et al, 2016 ). Several reports have shown that AHL may promote root length or induce AHL-priming for enhanced resistance ( Mathesius et al, 2003 ; Ortiz-Castro et al, 2008 ; Hartmann et al, 2014 ; Schikora et al, 2016 ; Zhao et al, 2020 ).…”

Microbial Derived Compounds, a Step Toward Enhancing Microbial Inoculants Technology for Sustainable Agriculture

“…Siderophores produced by Streptomyces acidiscabies E13 alleviated metal induced oxidative stress in cowpea plants ( Dimkpa et al, 2009 ). Zhao et al (2020) reported enhanced tolerance to salt by Arabidopsis thaliana plants treated with N-3-oxo-hexanoyl-homoserine lactone. Regulation of biomass and leaf arrangement in drought stressed Brassica napus [L.], treated with LCO was observed ( Schwinghamer et al, 2016 ).…”

“…Some compounds function by activation of genes responsible for production of certain phytohormones such as auxins and cytokinins ( Zhang et al, 2007 ; Contreras-Cornejo et al, 2009 ; Bai et al, 2012 ; Prudent et al, 2016 ; Piechulla et al, 2017 ), activation of enzymes and genes involved in disease resistance ( Duzan et al, 2005 ; Choi et al, 2014 ) and enhancing production of enzymes and genes, essential in stress management ( Jung et al, 2011 ; Zhou et al, 2016 ; Zhao et al, 2020 ) through processes such as inhibition of reactive oxygen species (ROS) production by plant cells ( Blom et al, 2011 ). For example, a study by Jung et al (2011) indicated that thuricin17 induced defense related enzymes in soybean leaves.…”