Pseudomonas biocontrol of kiwifruit canker: elucidating novel mechanisms of bioactivity

The bacterial disease kiwifruit canker (Psa) is a significant threat to the global kiwifruit industry. While treatments for Psa currently exist, these chemical approaches can cause environmental damage and are at risk from resistant Psa pathovars. There is consequently an urgent need for effective, sustainable treatments for Psa. During a successful previous collaboration between our labs at JIC; an internationally recognised centre of excellence for microbiology and plant science, and the major kiwifruit grower Zespri, we identified several naturally occurring, bioactive bacterial strains that strongly suppress Psa infections in greenhouse-grown kiwifruit. Subsequent work to identify the mechanism of bioactivity in each strain identified multiple previously uncharacterised biosynthetic gene clusters (BGCs), whose disruption abolishes Psa suppression in the lab.
This PhD project will undertake the in-depth characterisation of the bioactive BGCs and their resulting natural products to address the mode of action of our bioactive bacteria. The student will use natural-product biochemistry and bioassay-guided fractionation to isolate and structurally characterise the natural products of each bioactive BGC. They will examine their biosynthetic origin using a combination of genetics and targeted metabolomics, and will conduct biocontrol assays to determine the importance of their natural products in planta.
This project will support the ongoing field trial and bioactives registration work in New Zealand and define the structure-activity relationship of several new natural products, which is an essential step in their future commercial development. The student will receive training in advanced molecular biology and bacterial genetic manipulation, alongside cutting-edge organic chemistry techniques including LC-MS-based metabolomics, bioassay-guided fractionation and structural elucidation using 2D NMR. They will also receive extensive training in plant infection and biocontrol assays, alongside industry-facing, transferable soft-skills with applicability to many employment areas. This industry-linked project will include a 3 month placement working alongside our commercial partners, Zespri, in New Zealand.