Survival strategies of Enterococcus mundtii in the gut of Spodoptera littoralis : a live report

To monitor the dynamics and rapid adaptation of microbes to the gut conditions, a GFP-tagged reporter was constructed. After feeding to early instar larvae, the tagged-microbes recovered from the fore and hind guts by flow cytometry. The fluorescent reporter confirmed the persistence of in the gut. RNA-sequencing of the sorted bacteria highlighted various strategies that the symbiont employs to survive, including upregulated pathways for tolerating alkaline stress, forming biofilms and two-component signaling systems, resisting oxidative stress and quorum sensing. Although these symbionts depend on the host for amino acid and fatty acids, differential regulation among various metabolic pathways points to an enriched lysine synthesis pathway in the hindgut of the larvae.