Testing a lineage exclusion strategy for breeding rice resistant to blast disease

Rice blast, the disease caused by the fungus Pyricularia grisea Sacc. (teleomorph Magnaporthe grisea (Hebert) Barr.), has challenged plant breeding programs in their search for durable resistance. Rapid resistance breakdowns are commonly observed and are attributed to the frequent appearance of new...

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Main Author:	Tapiero Ortiz, Anibal Leonidas
Other Authors:	Morris Levy
Format:	doctoralThesis
Language:	Inglés
Published:	Purdue University 2019
Subjects:	Producción y tratamiento de semillas - F03 Genética vegetal y fitomejoramiento - F30 Patologia de las plantas Fitopatologia Hongos Transitorios
Online Access:	http://hdl.handle.net/20.500.12324/35008

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spelling	RepoAGROSAVIA350082023-02-21T01:02:37Z Testing a lineage exclusion strategy for breeding rice resistant to blast disease Tapiero Ortiz, Anibal Leonidas Morris Levy Producción y tratamiento de semillas - F03 Genética vegetal y fitomejoramiento - F30 Patologia de las plantas Fitopatologia Hongos Transitorios Rice blast, the disease caused by the fungus Pyricularia grisea Sacc. (teleomorph Magnaporthe grisea (Hebert) Barr.), has challenged plant breeding programs in their search for durable resistance. Rapid resistance breakdowns are commonly observed and are attributed to the frequent appearance of new pathotypes or to poor screening of the pathogen population prior to release. Recent population studies of the rice blast pathosystem have shown that P. grisea in a given region typically expresses a phylogenetic organization of distinct lineages (genetic families as defined by MGR-586 DNA fingerprinting). Each lineage exhibits a definable virulence spectrum and the potential for developing new pathotypes appears to be constrained by lineage-specific avirulences. Pyramiding resistance (R) genes in combinations that exclude the observed virulence spectra of each lineage can provide durable resistance to rice blast. The lineage exclusion strategy was tested on pyramids at three ecologically different sites in a primary rice growing region in Colombia, from 1996 to 1998. The pyramids were selected for resistance using isolates of representative Colombian lineages. The presence and homozygosity of the R-genes in the pyramid lines was confirmed with molecular markers. The pyramids proved to be highly resistant in commercial fields and no major changes in lineage composition or virulence spectrum were observed. However, some moderately virulent isolates were transiently observed in 1996 and 1997 but not in 1998 at a disease 'hot-spot' nursery. These isolates were all members of lineage SRL-6, the only lineage known previously to express virulence to both pyramided R-genes, although differentially by individual isolates. The new aggressiveness of lineage SRL-6 seemed to compromise only a sub-population of the pyramids and no mixture of isolates from other lineages, expressing a similar complement of differential virulences, was capable of infecting the pyramids. Doctor of Philosophy Doctorado 2019-04-30T18:37:02Z 2019-04-30T18:37:02Z 2001 doctoralThesis Tesis de doctorado http://purl.org/coar/resource_type/c_db06 info:eu-repo/semantics/doctoralThesis https://purl.org/redcol/resource_type/TD http://purl.org/coar/version/c_970fb48d4fbd8a85 http://hdl.handle.net/20.500.12324/35008 54993 reponame:Biblioteca Digital Agropecuaria de Colombia repourl:https://repository.agrosavia.co instname:Corporación colombiana de investigación agropecuaria AGROSAVIA eng Attribution-NonCommercial-ShareAlike 4.0 International http://creativecommons.org/licenses/by-nc-sa/4.0/ Acceso a texto completo info:eu-repo/semantics/openAccess 82 páginas application/pdf application/pdf Purdue University Purdue university Doctor Philosophy
institution	Corporación Colombiana de Investigación Agropecuaria
collection	Repositorio AGROSAVIA
language	Inglés
topic	Producción y tratamiento de semillas - F03 Genética vegetal y fitomejoramiento - F30 Patologia de las plantas Fitopatologia Hongos Transitorios
spellingShingle	Producción y tratamiento de semillas - F03 Genética vegetal y fitomejoramiento - F30 Patologia de las plantas Fitopatologia Hongos Transitorios Tapiero Ortiz, Anibal Leonidas Testing a lineage exclusion strategy for breeding rice resistant to blast disease
description	Rice blast, the disease caused by the fungus Pyricularia grisea Sacc. (teleomorph Magnaporthe grisea (Hebert) Barr.), has challenged plant breeding programs in their search for durable resistance. Rapid resistance breakdowns are commonly observed and are attributed to the frequent appearance of new pathotypes or to poor screening of the pathogen population prior to release. Recent population studies of the rice blast pathosystem have shown that P. grisea in a given region typically expresses a phylogenetic organization of distinct lineages (genetic families as defined by MGR-586 DNA fingerprinting). Each lineage exhibits a definable virulence spectrum and the potential for developing new pathotypes appears to be constrained by lineage-specific avirulences. Pyramiding resistance (R) genes in combinations that exclude the observed virulence spectra of each lineage can provide durable resistance to rice blast. The lineage exclusion strategy was tested on pyramids at three ecologically different sites in a primary rice growing region in Colombia, from 1996 to 1998. The pyramids were selected for resistance using isolates of representative Colombian lineages. The presence and homozygosity of the R-genes in the pyramid lines was confirmed with molecular markers. The pyramids proved to be highly resistant in commercial fields and no major changes in lineage composition or virulence spectrum were observed. However, some moderately virulent isolates were transiently observed in 1996 and 1997 but not in 1998 at a disease 'hot-spot' nursery. These isolates were all members of lineage SRL-6, the only lineage known previously to express virulence to both pyramided R-genes, although differentially by individual isolates. The new aggressiveness of lineage SRL-6 seemed to compromise only a sub-population of the pyramids and no mixture of isolates from other lineages, expressing a similar complement of differential virulences, was capable of infecting the pyramids.
author2	Morris Levy
author_facet	Morris Levy Tapiero Ortiz, Anibal Leonidas
format	doctoralThesis
author	Tapiero Ortiz, Anibal Leonidas
author_sort	Tapiero Ortiz, Anibal Leonidas
title	Testing a lineage exclusion strategy for breeding rice resistant to blast disease
title_short	Testing a lineage exclusion strategy for breeding rice resistant to blast disease
title_full	Testing a lineage exclusion strategy for breeding rice resistant to blast disease
title_fullStr	Testing a lineage exclusion strategy for breeding rice resistant to blast disease
title_full_unstemmed	Testing a lineage exclusion strategy for breeding rice resistant to blast disease
title_sort	testing a lineage exclusion strategy for breeding rice resistant to blast disease
publisher	Purdue University
publishDate	2019
url	http://hdl.handle.net/20.500.12324/35008
work_keys_str_mv	AT tapieroortizaniballeonidas testingalineageexclusionstrategyforbreedingriceresistanttoblastdisease
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Testing a lineage exclusion strategy for breeding rice resistant to blast disease

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