Evaluating the presence and introgression of the hybrid forest pathogen Cronartium x flexili
department or school: Forestry, Faculty of
data provider: DSpace
degree campus: UBCV
creator: Allen, Kiah
issued: 2019-08-21T15:54:04Z
issued: 2019
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: The recent discovery of a hybrid forest fungal pathogen, Cronartium x flexili, suggested to have arisen from sexual hybridization between the introduced C. ribicola and the native C. comandrae, was surprising because the parental species do not share hosts. Although the pathosystems of both parental species are well described, the impact of their hybridization is yet unknown. The purpose of this study is to determine the occurrence, level of hybridization and introgression of the hybrid pine stem rust Cronartium x flexili. A total of 831 samples from dikaryotic aecia of C. ribicola and C. comandrae were collected from 13 sites across British Columbia and Alberta and analysed both genetically and morphologically over two sampling seasons. Microscopic and genetic methods, including PCR, qPCR, and genotyping by sequencing (GBS), were used to identify hybrid samples. The results of these analyses indicate that C. x flexili is either no longer prevalent in areas where it was previously found, or else prevalent at such low frequencies that it has evaded detection in the sampling effort of this study. Two previously collected and extracted C. x flexili DNA samples were examined using a fixed loci analysis and did not demonstrate evidence of introgression, indicating that this hybrid does not facilitate gene flow between the introduced C. ribicola and the native C. comandrae. This suggests that when a hybridization event occurs between the parental Cronartium spp., first generation (F1) hybrids result but are not fertile and do not occur perennially. Some evidence suggests that this could be due to a number of factors including: low relative fitness of C. x flexili compared to the parental species if ‘hybrid breakdown’ occurs as explained by the Bateson-Dobzhansky-Muller incompatibility (BDMI) model; variations in local climate factors influencing life cycle parameters; or sexual incompatibility with the parental species. This work adds to the limited literature on the gene…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/71361
note: Evaluating the presence and introgression of the hybrid forest pathogen Cronartium x flexili by Kiah Allen B. Sc., The University of British Columbia, 2017 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in The Faculty of Graduate and Postdoctoral Studies (Forestry) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) August 2019 ©Kiah Allen, 2019 ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, the thesis entitled: Evaluating the presence and introgression of the hybrid forest pathogen Cronartium x flexili submitted by Kiah Allen in partial fulfillment of the requirements for the degree of Master of Science in Forestry Examining Committee: Richard Hamelin, Forest and Conservation Sciences Supervisor Nicholas Feau, Forest and Conservation Sciences Supervisory committee member Yousry El Kassaby, Forest and Conservation Sciences Supervisory committee member Chris Chanway, Land and Food Systems Additional Examiner iii Abstract The recent discovery of a hybrid forest fungal pathogen, Cronartium x flexili, suggested to have arisen from sexual hybridization between the introduced C. ribicola and the native C. comandrae, was surprising because the parental species do not share hosts. Although the pathosystems of both parental species are well described, the impact of their hybridization is yet unknown. The purpose of this study is to determine the occurrence, level of hybridization and introgression of the hybrid pine stem rust Cronartium x flexili. A total of 831 samples from dikaryotic aecia of C. ribicola and C. comandrae were collected from 13 sites across British Columbia and Alberta and analysed both genetically and morphologically over two sampling seasons. Microscopic and genetic methods, including PCR, qPCR, and genotyping by sequencing (GBS), were used to identify hybrid samples. The results of these analyses indicate that C. x fl…
has type: Thesis/Dissertation
date issued: 2019-09
is shown at: 10.14288/1.0380531
language: eng
degree discipline: Forestry
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/71361