Shoot the Message, Not the Messenger—Combating Pathogenic Virulence in Plants by Inhibiting Quorum Sensing Mediated Signaling Molecules

Abstract

Immunity, virulence, biofilm formation, and survival in the host environment are regulated by the versatile nature of density dependent microbial cell signaling, also called quorum sensing (QS). The QS molecules can associate with host plant tissues and, at times, cause a change in its gene expression at the downstream level through inter-kingdom cross talking. Progress in controlling QS through fungicide/bactericide in pathogenic microscopic organisms has lead to a rise of antibiotic resistance pathogens. Here, we review the application of selective quorum quenching (QQ) endophytes to control phytopathogens that are shared by most, if not all, terrestrial plant species as well as aquatic plants. Allowing the plants to posses endophytic colonies through biotization will be an additional and a sustainable encompassing methodology resulting in attenuated virulence rather than killing the pathogens. Furthermore, the introduced endophytes could serve as a potential biofertilizer and bioprotection agent, which in turn increases the PAMP- triggered immunity and hormonal systemic acquired resistance (SAR) in plants through SA-JA-ET signaling systems. This paper discusses major challenges imposed by QS and QQ application in biotechnology.

Anti-quorum sensing agents: a potential alternative for antibiotics

“…These microbes increase plant immunity against phytopathogens by helping them to obtain more transition metals by producing siderophores (Fones and Preston, 2013). Apart from producing AHLdegrading enzymes these quorum quenching microbes will occupy most of the intercellular space thus leaving very few spaces for later-invading phyto-pathogenic bacteria (Alagarasan et al, 2017). aeruginosa (Kaufmann et al, 2007).…”

A review article: Anti-quorum sensing agents as a potential replacement for antibiotics in Phytobacteriology

“…These microbes increases plant immunity against phytopathogens by helping them to obtain more transition metals by producing siderophores (Fones and Preston, 2013) [19] . Apart from producing AHL-degrading enzymes these QQ microbes will occupy most of the intercellular space thus leaving very few spaces for laterinvading phyto-pathogenic bacteria (Alagarasan et al, 2017) [1] (Table 1). Another way is by Mutagenesis, in A. tumefaciens, production of the AHL lactonase is encoded by attM which in normal condition gets suppressed by the negative transcription factor attJ.…”

Biological Control of Potato Tuber Soft Rot using <i>N</i>-Acyl-L-Homoserine Lactone-Degrading Endophytic Bacteria

“…The disruption of QS signalling, also called 'quorum quenching' (QQ), has been described in bacteria, fungi, plants, animals, etc. [5][6][7][8] . The use of endophytic bacteria living inside plant tissues capable of naturally degrading AHL produced by pathogens has been considered as a suitable approach to interfere with infection 9 .…”