Modelling the mechanisms of olive die back caused by Xylella fastidiosa biofilms

Lead Research Organisation: University of Southampton
Department Name: Sch of Ocean and Earth Science

Abstract

Xylella fastidiosa is a globally important bacterial pathogen that attacks many plants of economic importance. Initially it was restricted to the Americas, but in 2013 it was detected in Lecce, Italy in 2013. Since the initial outbreak, it has invaded large swathes of olives in southern Italy, and is of great concern throughout Mediterranean basin and beyond. Exploring the mechanisms by which the bacterium grows within the host plant, forming a biofilm, is critical for our understanding future control methods. This project will develop mathematical models of biofilm and associated plant disease spread related to Xylella fastidiosa.

Studentship Projects

Project Reference Relationship Related To Start End Student Name
NE/S007210/1 01/10/2019 30/09/2027
2293508 Studentship NE/S007210/1 01/10/2019 30/09/2023 Nancy Walker
 
Description 1. Stems from four olive cultivars of varying susceptibility to X. fastidiosa were scanned via X-ray Computed Tomography. Scans were processed via a bespoke methodology that facilitated diameter measurements. This methodology is easily adaptable for application to any images for which biological pores need to be segmented.
2. Considering Young-Laplace and Hagen-Poiseuille equations, we could infer the impact of vessel diameters, particularly the lack of the largest vessels, in Leccino on it resistance to air embolisms and maintenance of hydraulic conductivity. In previous studies, no evidence is provided as to the mechanisms by which differences in vessel diameters could act to limit disease symptoms.
3. The first imaging study has lead to a collaboration with researchers in Brazil, where I am leading a high-throughput high-resolution synchrotron imaging study of infected and non-infected plant stems.
4. A novel mathematical model was developed to describe biofilm behaviour in xylem vessels. Unlike previous models described in the literature, this model is able to capture the interaction between biofilm and sap flow with minimal reliance on experimental parameters.
Exploitation Route 1. The image processing framework could be adapted for images of different quality, as I am doing for the synchrotron data produced for my next study, or to segment images of other biological pores.
2. The developed mathematical model could be adapted to answer questions relating to the internal dynamics associated with any biofilm-induced plant vascular diseases.
3. The results from imaging and modelling studies suggest that vessel diameter distributions likely play a role in the disease resistance of cultivar Leccino, but not FS17. This information supports the integration of a xylem morphological screening to help inform future olive re-planting.
Sectors Agriculture, Food and Drink,Environment
 
Title Dataset for: The Impact of Xylem Geometry on Olive Cultivar Resistance to Xylella fastidiosa: An Image-based Study 
Description Image stacks supporting the publication 'The Impact of Xylem Geometry on Olive Cultivar Resistance to Xylella fastidiosa: An Image-based Study' in Plant Pathology. 
Type Of Material Database/Collection of data 
Year Produced 2022 
Provided To Others? Yes  
Impact See publication: Walker, N.C., White, S.M., McKay Fletcher, D., Ruiz, S.A., Rankin, K.E., De Stradis, A., Saponari, M., Williams, K.A., Petroselli, C. and Roose, T., 2022. The impact of xylem geometry on olive cultivar resistance to Xylella fastidiosa: An image-based study. Plant Pathology.