Hydrolysis of aromatic beta-glucosides by non-pathogenic bacteria confers a chemical weapon against predators

Sonowal, Robert and Nandimath, Krithi and Kulkarni, Sucheta S and Koushika, Sandhya P and Nanjundiah, Vidyanand and Mahadevan, S (2013) Hydrolysis of aromatic beta-glucosides by non-pathogenic bacteria confers a chemical weapon against predators. In: Proceedings of the Royal Society B-Biological Sciences, 280 (1762). 20130721_1-20130721_9.

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Abstract

Bacteria present in natural environments such as soil have evolved multiple strategies to escape predation. We report that natural isolates of Enterobacteriaceae that actively hydrolyze plant-derived aromatic beta-glucosides such as salicin, arbutin and esculin, are able to avoid predation by the bacteriovorous amoeba Dictyostelium discoideum and nematodes of multiple genera belonging to the family Rhabditidae. This advantage can be observed under laboratory culture conditions as well as in the soil environment. The aglycone moiety released by the hydrolysis of beta-glucosides is toxic to predators and acts via the dopaminergic receptor Dop-1 in the case of Caenorhabditis elegans. While soil isolates of nematodes belonging to the family Rhabditidae are repelled by the aglycone, laboratory strains and natural isolates of Caenorhabditis sp. are attracted to the compound, mediated by receptors that are independent of Dop-1, leading to their death. The b-glucosides-positive (Bgl(+)) bacteria that are otherwise non-pathogenic can obtain additional nutrients from the dead predators, thereby switching their role from prey to predator. This study also offers an evolutionary explanation for the retention by bacteria of `cryptic' or `silent' genetic systems such as the bgl operon.

Item Type:	Journal Article
Publication:	Proceedings of the Royal Society B-Biological Sciences
Publisher:	Royal Society
Additional Information:	Copyright of this article belongs to Royal Society.
Keywords:	Aromatic Beta-Glucosides; Bgl Operon; Caenorhabditis Elegans; Dictyostelium Discoideum; Enterobacteriaceae; Predator-Prey Interaction
Department/Centre:	Division of Biological Sciences > Molecular Reproduction, Development & Genetics
Date Deposited:	11 Jul 2013 11:12
Last Modified:	11 Jul 2013 11:12
URI:	http://eprints.iisc.ac.in/id/eprint/46777

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