Using targeted phenomics and environmental proxies to understand Phytophthora medicaginis and Phytophthora root rot resistance in Australian chickpea
type: CreativeWork
description: Australian chickpea production is constrained by Phytophthora root rot (PRR), caused by the soil-borne oomycete Phytophthora medicaginis. Yield penalties are exacerbated by waterlogging resulting in partial or complete crop losses with few control options. Higher levels of PRR resistance have been identified in wild Cicer species but are associated with undesirable traits due to genetic linkage drag. Understanding the mechanisms involved in waterlogging tolerance and PRR resistance traits is necessary to determine if they can be uncoupled from poor agronomic traits when breeding improved varieties. The aims of this research were to; (1) investigate and characterise the response of both chickpea and the PRR causing organism, P. medicaginis, to waterlogging stress, (2) identify mechanisms of resistance using waterlogging as a proxy, (3) phenotype flavonoid phytoalexin metabolite accumulation associated with resistance following PRR infection, and (4) identify associated quantitative trait loci (QTL) with discoverable traits. Under waterlogging conditions, oxygen levels in soil are reduced and the plant itself compromised through physiological and structural changes that increase the sensitivity of chickpea to PRR infection. This research found that late waterlogging in combination with PRR reduced total plant biomass in chickpea by an average of 94%; however, waterlogging alone accounted for 88% of loss. Further experimentation found that under hypoxic conditions associated with waterlogging, P. medicaganis did not proliferate as determined by zoospore counts and DNA quantification using qPCR, due to oxygen requirements of the pathogen. These results demonstrate that waterlogging alone can result in plant stunting, yield loss and a reduced ability to express resistance. Chickpea genotypes demonstrated variability in phenotype, such as plant biomass and root parameters, when exposed to waterlogging stress. Following waterlogging conditions, the PRR moderately susceptib…
abstract: Australian chickpea production is constrained by Phytophthora root rot (PRR), caused by the soil-borne oomycete Phytophthora medicaginis. Yield penalties are exacerbated by waterlogging resulting in partial or complete crop losses with few control options. Higher levels of PRR resistance have been identified in wild Cicer species but are associated with undesirable traits due to genetic linkage drag. Understanding the mechanisms involved in waterlogging tolerance and PRR resistance traits is necessary to determine if they can be uncoupled from poor agronomic traits when breeding improved varieties. The aims of this research were to; (1) investigate and characterise the response of both chickpea and the PRR causing organism, P. medicaginis, to waterlogging stress, (2) identify mechanisms of resistance using waterlogging as a proxy, (3) phenotype flavonoid phytoalexin metabolite accumulation associated with resistance following PRR infection, and (4) identify associated quantitative trait loci (QTL) with discoverable traits. Under waterlogging conditions, oxygen levels in soil are reduced and the plant itself compromised through physiological and structural changes that increase the sensitivity of chickpea to PRR infection. This research found that late waterlogging in combination with PRR reduced total plant biomass in chickpea by an average of 94%; however, waterlogging alone accounted for 88% of loss. Further experimentation found that under hypoxic conditions associated with waterlogging, P. medicaganis did not proliferate as determined by zoospore counts and DNA quantification using qPCR, due to oxygen requirements of the pathogen. These results demonstrate that waterlogging alone can result in plant stunting, yield loss and a reduced ability to express resistance. Chickpea genotypes demonstrated variability in phenotype, such as plant biomass and root parameters, when exposed to waterlogging stress. Following waterlogging conditions, the PRR moderately susceptib…
author: Dron, Nicole Marie
language: en
keywords: Chickpea, Phytophthora medicaginis, pathology, breeding
date published: 2023
date modified: 2026-07-24T00:50:39Z
provider: University of Adelaide
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Adelaide

PropertyValue
property ID: Handle
value: https://hdl.handle.net/2440/139880