Pyrazines from bacteria and ants: convergent chemistry within an ecological niche

Eduardo A Silva-Junior,Camila R Paludo,Antonio C Ruzzini,Jon Clardy,Mônica T Pupo,Fabio S Nascimento,Cameron R Currie

doi:10.1038/s41598-018-20953-6

Eduardo A Silva-Junior, Camila R Paludo + Show 5 more

Open Access

https://doi.org/10.1038/s41598-018-20953-6

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Abstract

Ants use pheromones to coordinate their communal activity. Volatile pyrazines, for instance, mediate food resource gathering and alarm behaviors in different ant species. Here we report that leaf-cutter ant-associated bacteria produce a family of pyrazines that includes members previously identified as ant trail and alarm pheromones. We found that L-threonine induces the bacterial production of the trail pheromone pyrazines, which are common for the host leaf-cutter ants. Isotope feeding experiments revealed that L-threonine along with sodium acetate were the biosynthetic precursors of these natural products and a biosynthetic pathway was proposed.

Highlights

Ants use pheromones to coordinate their communal activity
We provide the first report of a leaf-cutter ant-associated bacterium, Serratia marcescens 3B2, that is capable of producing pyrazines previously identified as trail pheromones (1 and 2) of the host ant Atta sexdens rubropilosa and alarm pheromones (4 and 5) of other ants[8,9,11,20]
In order to investigate if the trail pheromone pyrazines 1 and 2, found in the hosts ants (Figs S11–S13, ESI†), could be produced by the bacterium, we examined the metabolites from a single isolate – S. marcescens 3B2 – using minimal and defined growth media

Summary

Introduction

Ants use pheromones to coordinate their communal activity. Volatile pyrazines, for instance, mediate food resource gathering and alarm behaviors in different ant species. Pyrazines are components of the trail pheromones produced by the poison glands of the leaf-cutter ants Acromyrmex octospinosus, Atta bisphaerica, Atta cephalotes, and Atta sexdens[7,12,13]. These natural products likewise mediate communication in bacteria: 3,5-dimethylapyrazin-2-ol is a quorum sensing regulator implicated in biofilm formation by Vibrio cholerae[14]. We provide the first report of a leaf-cutter ant-associated bacterium, Serratia marcescens 3B2, that is capable of producing pyrazines previously identified as trail pheromones (1 and 2) of the host ant Atta sexdens rubropilosa and alarm pheromones (4 and 5) of other ants[8,9,11,20]. The biosynthetic precursors of the trail pheromone pyrazines were unveiled by isotope feeding experiments

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