{"id":{"repo_id":"uwo","oai_identifier":"oai:uwo.scholaris.ca:20.500.14721/35450"},"canonical_url":"https://search.dev.ndltd.org/etd/uwo/oai:uwo.scholaris.ca:20.500.14721/35450","repository":{"repo_id":"uwo","name":"Western University","base_url":"https://uwo.scholaris.ca/server/oai/request"},"display":{"title":"Inheritance of virulence in the root rot pathogen Phytophthora sojae","abstract":"The oomycete Phytophthora sojae causes stem and root rot of soybean plants. The interaction of pathogen avirulence (Avr) and host resistance (R)-genes determine the disease outcome. The Avr3a mRNA transcript level is variable among P. sojae strains and determines virulence towards the R-gene Rps3a. To study the inheritance of virulence, genetic crosses and self-fertilizations were performed. A cross between P. sojae strains ACR10 and P7076 causes transgenerational gene silencing of Avr3a allele, and this effect is meiotically stable up to the F5 generation. However, test-crosses of F1 (Avr3aACR10/Avr3aP7076) with strain P6497 result in expression of Avr3a in all progeny and release of silencing of the Avr3aP7076 allele. Progeny from P6497 X ACR10 crosses showed unusual inheritance for Avr3a expression. Overall, we conclude that Avr3a gene silencing is strain specific and could rely on epistatic factors. This study will lead to a better understanding of infection and virulence mechanisms that will help to better manage and safeguard soybean production.","abstract_html":"The oomycete Phytophthora sojae causes stem and root rot of soybean plants. The interaction of pathogen avirulence (Avr) and host resistance (R)-genes determine the disease outcome. The Avr3a mRNA transcript level is variable among P. sojae strains and determines virulence towards the R-gene Rps3a. To study the inheritance of virulence, genetic crosses and self-fertilizations were performed. A cross between P. sojae strains ACR10 and P7076 causes transgenerational gene silencing of Avr3a allele, and this effect is meiotically stable up to the F5 generation. However, test-crosses of F1 (Avr3aACR10/Avr3aP7076) with strain P6497 result in expression of Avr3a in all progeny and release of silencing of the Avr3aP7076 allele. Progeny from P6497 X ACR10 crosses showed unusual inheritance for Avr3a expression. Overall, we conclude that Avr3a gene silencing is strain specific and could rely on epistatic factors. This study will lead to a better understanding of infection and virulence mechanisms that will help to better manage and safeguard soybean production.","abstract_has_math":false,"creators":["Shrestha, Sirjana Devi"],"institution":"The University of Western Ontario","degree_name":"M Sc","degree_level":null,"degree_discipline":"Biology","degree_department":null,"school":null,"contributors":[],"advisors":["Mark Gijzen"],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-12-12","date_published":"2014-12-12","updated_at":"2026-07-27T21:56:18Z","subjects":["Phytophthora sojae","soybean","virulence","avirulence","genetic crosses","oospore","Avr3a gene","transcript","RT-PCR","gene silencing","epistatic","gene conversion"],"languages":["en_ca"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/20.500.14721/35450","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Mark Gijzen"]},{"key":"dc:creator","label":"Author","values":["Shrestha, Sirjana Devi"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2025-07-10T20:37:54Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2025-07-10T20:37:54Z"]},{"key":"dc:date.issued","label":"Date","values":["2014-12-12"]},{"key":"dc:publisher","label":"Institution","values":["The University of Western Ontario"]},{"key":"dc:type","label":"Dc Type","values":["thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Biology"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M Sc"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Phytophthora sojae","soybean","virulence","avirulence","genetic crosses","oospore","Avr3a gene","transcript","RT-PCR","gene silencing","epistatic","gene conversion"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en_ca"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/20.500.14721/35450"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The thesis cover page in the PDF document includes references to Western University’s previous institutional repository platform, known as Scholarship@Western, and links to that platform (beginning with ir.lib.uwo.ca). In citing or referring to this thesis, use the DOI or handle from this page instead. Sample citation: Author name, \"Thesis title.\" (Year). Western University Open Repository. https://doi.org/10.71858/123456."]},{"key":"dc:description.abstract","label":"Abstract","values":["The oomycete Phytophthora sojae causes stem and root rot of soybean plants. The interaction of pathogen avirulence (Avr) and host resistance (R)-genes determine the disease outcome. The Avr3a mRNA transcript level is variable among P. sojae strains and determines virulence towards the R-gene Rps3a. To study the inheritance of virulence, genetic crosses and self-fertilizations were performed. A cross between P. sojae strains ACR10 and P7076 causes transgenerational gene silencing of Avr3a allele, and this effect is meiotically stable up to the F5 generation. However, test-crosses of F1 (Avr3aACR10/Avr3aP7076) with strain P6497 result in expression of Avr3a in all progeny and release of silencing of the Avr3aP7076 allele. Progeny from P6497 X ACR10 crosses showed unusual inheritance for Avr3a expression. Overall, we conclude that Avr3a gene silencing is strain specific and could rely on epistatic factors. This study will lead to a better understanding of infection and virulence mechanisms that will help to better manage and safeguard soybean production."]},{"key":"dc:title","label":"Title","values":["Inheritance of virulence in the root rot pathogen Phytophthora sojae"]}]}],"canonical_facts":{"dc:contributor.advisor":["Mark Gijzen"],"dc:creator":["Shrestha, Sirjana Devi"],"dc:date.accessioned":["2025-07-10T20:37:54Z"],"dc:date.available":["2025-07-10T20:37:54Z"],"dc:date.issued":["2014-12-12"],"dc:description":["The thesis cover page in the PDF document includes references to Western University’s previous institutional repository platform, known as Scholarship@Western, and links to that platform (beginning with ir.lib.uwo.ca). In citing or referring to this thesis, use the DOI or handle from this page instead. Sample citation: Author name, \"Thesis title.\" (Year). Western University Open Repository. https://doi.org/10.71858/123456."],"dc:description.abstract":["The oomycete Phytophthora sojae causes stem and root rot of soybean plants. The interaction of pathogen avirulence (Avr) and host resistance (R)-genes determine the disease outcome. The Avr3a mRNA transcript level is variable among P. sojae strains and determines virulence towards the R-gene Rps3a. To study the inheritance of virulence, genetic crosses and self-fertilizations were performed. A cross between P. sojae strains ACR10 and P7076 causes transgenerational gene silencing of Avr3a allele, and this effect is meiotically stable up to the F5 generation. However, test-crosses of F1 (Avr3aACR10/Avr3aP7076) with strain P6497 result in expression of Avr3a in all progeny and release of silencing of the Avr3aP7076 allele. Progeny from P6497 X ACR10 crosses showed unusual inheritance for Avr3a expression. Overall, we conclude that Avr3a gene silencing is strain specific and could rely on epistatic factors. This study will lead to a better understanding of infection and virulence mechanisms that will help to better manage and safeguard soybean production."],"dc:identifier.uri":["https://hdl.handle.net/20.500.14721/35450"],"dc:language.iso":["en_ca"],"dc:publisher":["The University of Western Ontario"],"dc:subject":["Phytophthora sojae","soybean","virulence","avirulence","genetic crosses","oospore","Avr3a gene","transcript","RT-PCR","gene silencing","epistatic","gene conversion"],"dc:title":["Inheritance of virulence in the root rot pathogen Phytophthora sojae"],"dc:type":["thesis"],"thesis:degree_discipline":["Biology"],"thesis:degree_name":["M Sc"]},"updated_at":"2026-07-27T21:56:18Z"}