Genetically engineering Pseudomonas strains for T6SS-dependent controlled release of effectors.

Abstract

Type VI secretion systems (T6SS) are Gram-negative bacteria’s syringe-like nanomachine that injects effectors into prokaryotic and eukaryotic cells leading to the death of their target. These systems have the potential to be genetically engineered for their application in different biotechnological fields such as medicine or agriculture. As proof of concept, in this work we have genetically engineered the well-known soil-dwelling Pseudomonas putida KT2440 strain, achieving the controlled expression of related and non-related T6SS effectors. These results open a window of opportunities to secrete a wide range of molecules to different targets using this Pseudomonas strain as bacterial chassis. Specifically, this work shows promising results in the agriculture field as genetically modified P. putida KT2440 strains overexpressing T6SS-related effector Tfe2 and T6SS-non-related effector chitosanase can now inhibit bacterial and fungal strains such as the phytopathogen Botrytis cinerea.