Investigation of host cell wall degrading strategies of Pseudomonas syringae pv. actinidiae (Psa)
type: CreativeWork
description: Kiwifruit (Actinidia deliciosa and Actinidia chinensis) is cultivated in several countries including Italy, France, Chile, China, Japan, Korea and New Zealand and is an important income earner for a majority of these countries. In New Zealand, kiwifruit earns approximately USD 714 million per annum. In the recent past, the New Zealand kiwifruit industry was threatened by an outbreak of bacterial canker caused by Pseudomonas syringae pv. actinidiae (Psa). The invasion strategies and the mobility of Psa pathogen in the kiwifruit plant have not been fully described. Recent comparative genomic studies of Psa strains and other P. syringae pathovars that also infect woody hosts indicate similarities in genetic makeup among these pathovars. Interestingly, these pathovars contain genes capable of producing cell wall degrading enzymes, thus suggesting that Psa possesses the same capability. However, no previous research demonstrated that any P. syringae pathovar degrades the host’s cell walls or any cell wall component. This research investigated whether Psa produces xylanases to degrade cell wall material of kiwifruit stems and facilitate systemic mobility of the pathogen from the infection site. The research also investigates whether vessel anatomy and xylem architecture play a role in the systemic mobility of the pathogen within the plant. Chapter Two of the thesis determines whether Psa is able to multiply and grow on kiwifruit wood-containing medium and whether Psa synthesises any xylanase to degrade cell wall material contained in the kiwifruit wood. For this purpose, the genome of Psa was analysed to ascertain whether sequences homologous to well-known cell wall degrading enzymes were present in the genome. The degree of similarity of the identified genes was compared to the cell wall degrading genes of other Pseudomonas woody host pathogens. Six genes encoding for well-known cell wall degrading enzymes were identified, with the degree of amino acid similarity varying…
abstract: Kiwifruit (Actinidia deliciosa and Actinidia chinensis) is cultivated in several countries including Italy, France, Chile, China, Japan, Korea and New Zealand and is an important income earner for a majority of these countries. In New Zealand, kiwifruit earns approximately USD 714 million per annum. In the recent past, the New Zealand kiwifruit industry was threatened by an outbreak of bacterial canker caused by Pseudomonas syringae pv. actinidiae (Psa). The invasion strategies and the mobility of Psa pathogen in the kiwifruit plant have not been fully described. Recent comparative genomic studies of Psa strains and other P. syringae pathovars that also infect woody hosts indicate similarities in genetic makeup among these pathovars. Interestingly, these pathovars contain genes capable of producing cell wall degrading enzymes, thus suggesting that Psa possesses the same capability. However, no previous research demonstrated that any P. syringae pathovar degrades the host’s cell walls or any cell wall component. This research investigated whether Psa produces xylanases to degrade cell wall material of kiwifruit stems and facilitate systemic mobility of the pathogen from the infection site. The research also investigates whether vessel anatomy and xylem architecture play a role in the systemic mobility of the pathogen within the plant. Chapter Two of the thesis determines whether Psa is able to multiply and grow on kiwifruit wood-containing medium and whether Psa synthesises any xylanase to degrade cell wall material contained in the kiwifruit wood. For this purpose, the genome of Psa was analysed to ascertain whether sequences homologous to well-known cell wall degrading enzymes were present in the genome. The degree of similarity of the identified genes was compared to the cell wall degrading genes of other Pseudomonas woody host pathogens. Six genes encoding for well-known cell wall degrading enzymes were identified, with the degree of amino acid similarity varying…
author: Subasinghe, Rasika
keywords: Psa, kiwifruit
license: https://researchcommons.waikato.ac.nz/bitstreams/b1bb5b8e-841b-49ef-b826-cd470eb30c0c/download
date published: 2018
date modified: 2026-07-24T05:57:27Z
provider: University Waikato
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: The University of Waikato