Pseudomonas biocontrol of kiwifruit canker: elucidating novel mechanisms of bioactivity

猕猴桃溃疡病（Psa）是严重威胁全球猕猴桃产业的一种细菌性病害。虽然目前存在Psa的治疗方法，但这些化学方法可能会造成环境破坏，并面临耐药Psa致病变种的风险。因此，迫切需要有效的，可持续的治疗Psa。在我们在JIC的实验室之间的成功合作中;国际公认的微生物学和植物科学卓越中心，以及主要的猕猴桃种植者Zespri，我们确定了几种天然存在的生物活性细菌菌株，可以强烈抑制温室种植的猕猴桃中的Psa感染。随后的工作，以确定每个菌株的生物活性的机制，确定了多个以前未表征的生物合成基因簇（BGC），其破坏废除了实验室中的Psa抑制。这个博士项目将进行生物活性BGC及其产生的天然产物的深入表征，以解决我们的生物活性细菌的作用模式。学生将使用天然产物生物化学和生物测定指导的分馏，以分离和结构化每个生物活性BGC的天然产物。他们将结合遗传学和靶向代谢组学研究其生物合成来源，并将进行生物控制分析，以确定其天然产物在植物中的重要性。该项目将支持正在进行的新西兰田间试验和生物活性物质注册工作，并确定几种新天然产物的结构-活性关系，这是其未来商业开发的重要一步。学生将接受先进分子生物学和细菌遗传操作的培训，以及尖端的有机化学技术，包括基于LC-MS的代谢组学，生物测定指导的分馏和使用2D NMR的结构解析。他们还将接受植物感染和生物控制检测方面的广泛培训，以及面向行业的可转移软技能，适用于许多就业领域。这个与行业相关的项目将包括在新西兰与我们的商业合作伙伴Zespri一起工作3个月。

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.