Bacterial type six secretion system and phytoprotection
Le potentiel phytoprotecteur des Pseudomonas fluorescens.
Résumé
T6SSs are macromolecular machineries that are utilized by bacteria to inject diverse effectors into prokaryotic and/or eukaryotic cells by using a contractile sheath. These systems propel a tip containing effectors to target cell. The most studied effectors exhibit antibacterial activity. T6SS can be considering as a main player in the control of evolution of microbial population within various niches.
We demonstrated that the Pseudomonas fluorescens MFE01 strain could protect potato tubers against Pectobacterium atrosepticum, which causes tuber soft rot. P. fluorescens is often described as a major PGPR and our results demonstrate a connection between the T6SS and the PGPR properties of this bacterium [1]. The MFE01 strain possesses a functional T6SS [2]. The presence of three different orphan genes encoding the tip (hcp1, hcp2, hcp3) allows various declinations of T6SS. The T6SSs containing Hcp2 or Hcp3 exhibit an antibacterial activity [2;3], in contrary to the T6SS formed by Hcp1 [4] that acts on bacterial motility. The understanding of the T6SS regulation in planta should allow us to develop products based on this strain combined with the biocontrol agent, Rhodococcus erythropolis [5-7] to protect potato tubers.