Xanthomonas arboricola pv. pruni (Xap) causes bacterial spot of stone fruits, an economically threatening, invasive disease of apricot, peach, plum and cherry. We recently discovered this EPPO A2 quarantine pathogen for the first time in Valais, Switzerland. The objective of this project was to marshal proactive research critical to address the potential threat that could be posed by wider invasion. Specifically, this project applied genomics as a foundation for understanding pathogen virulence and host-interactions with the long-term goal of designing implementable control strategies. This project also addressed short-term research needs to design genomics-informed pathogen detection tools critical for phytosanitary strategies to manage Xap. Lack of genetic understanding of Xap has been a major obstacle to progress with this problem. This project filled this gap and moved the field significantly forward by sequencing the complete genome of Xap. We have been able to identify the main pathogen virulence arsenal. We have further applied genomics to design the first molecular detection/diagnostic assays for this pathogen. Moreover, we have applied this first genome to sequence genomes of further genotypes and genomes of related pathogens of walnut and strawberry. Additionally, within this project we pioneered novel application of MALDI-TOF mass spectrometry for identification and phylogenetic analysis of Xanthomonas and other genera containing stone fruit and nut pathogens. This project enabled us to play a central role in establishing a Europe-wide network of bacteriologists, NGO culture collections and small industry. This has catapulted Swiss research capacity to the forefront of European phytobacteriology. This project was a critical driver for the EU COST Action as documented in output publically available at
http://www.cost873.ch. The results of this project have been communicated in dozens of international conference presentations and in 8 peerreviewed publications as first or co-author group. Aside from the scientific advances achieved during this project, this project involved a large number of training exchanges (10 STSMs hosted in CH to work on aspects of the project and/or pursue added-value extension of project themes) that will have long-term capacity building benefits to our group and Swiss phytobacteriology.
