20160426_Payne1
Quantum pathogen evolution by integron mediated capture
Plant pathogenic Pseudomonads are responsible for the loss of millions of pounds in crop revenue each year. Pseudomonads export effector molecules into the plants' cells in order to supress immune responses such as the plant hypersensitive response (HR). The plants immune system can recognise certain effector molecules and trigger the HR preventing bacterial infection. Pseudomonads can evade HR by potentially gaining different effector molecules captured within integrons. There are genes conserved within integrons that can be identified such as xerC and the UV damage repair gene rulB, encoding a DNA polymerase V, appears to be a hotspot for integron insertion. Using these features it has been possible to identify a number of integron-like elements (ILEs) within Pseudomonas syringae pathovars. The three regions used to identify potential ILEs were the rulAB operon, the xerC gene and the ILE insertion junction, rulB-xerC. The screening of 164 strains revealed new uncharacterised ILEs from 22 strains all containing at least one type three effector molecule. The screening also revealed that the XerC integrase is conserved across multiple ILEs within plant pathogens. Research has also been carried on UV tolerance of ILE strains to ascertain whether the disrupted rulB gene is still functional. The conditions required for ILE gene expression has also been assessed.