Identification of Molecular Markers Associated with the Rps8 locus in Soybean and Evaluation of Microsporogenesis in Rps8/rps8 Heterozygous Lines

Bibliographic Details
Main Author:	Ortega, Maria Andrea
Language:	English
Published:	The Ohio State University / OhioLINK 2009
Subjects:	Plant Pathology Soybean Phytophthora sojae stem and root rot chromosome 13 segregation distortion microsporogenesis microcytes molecular mapping graphical genotype ssr genotyping snp genotyping marker assisted selection disease resistance oomycete r genes
Online Access:	http://rave.ohiolink.edu/etdc/view?acc_num=osu1259772038

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spelling	ndltd-OhioLink-oai-etd.ohiolink.edu-osu12597720382021-08-03T05:57:37Z Identification of Molecular Markers Associated with the <i>Rps</i>8 locus in Soybean and Evaluation of Microsporogenesis in <i>Rps</i>8/<i>rps</i>8 Heterozygous Lines Ortega, Maria Andrea Plant Pathology Soybean Phytophthora sojae stem and root rot chromosome 13 segregation distortion microsporogenesis microcytes molecular mapping graphical genotype ssr genotyping snp genotyping marker assisted selection disease resistance oomycete r genes Phytophthora root and stem rot caused by <i>Phytophthora sojae</i> Kaufm. & Gerd. is one of the most damaging diseases of soybean, with an estimated worldwide loss of revenue of $1-2 billion per year. Management is principally done by planting cultivars with resistance. Monogenic race specific resistance genes to <i>P. sojae</i> (<i>Rps</i>) confer resistance to pathogen strains carrying the virulence gene (Avr). The durability of a deployed gene in the field is limited by generation of new virulence pathotypes of <i>P. sojae</i> that can evade the <i>Rps</i>-mediated immunity. <i>Rps</i>8 was identified in the South Korean landrace PI 399073 and to facilitate its introduction in commercial cultivars, molecular markers closely linked with the locus are required. These markers can also assist in the cloning of this gene, allowing us to enrich the knowledge on: the genomic organization and structure of <i>Rps</i> genes and the study of soybean-<i>P. sojae</i> race specific interactions. In this study, resistance to <i>P. sojae</i> was evaluated on eight Williams (rps8/rps8) x PI 399073 (<i>Rps</i>8/<i>Rps</i>8) populations, and one PI 399073 (<i>Rps</i>8/<i>Rps</i>8) x PI 408211B (multiple <i>Rps</i> genes) population. In the Williams x PI 399073 crosses, phenotypic ratios were highly skewed with an excess of <i>Rps</i>8/<i>Rps</i>8 lines, maintenance of heterozygosity and few <i>rps</i>8/<i>rps</i>8 lines. A graphical genotype was generated from three Williams x PI 399073 BC<sub>4</sub>F<sub>2:3</sub> populations as <i>Rps</i>8 was associated with a 2.23 Mbp region on chromosome 13. The linkage of this region with <i>Rps</i>8 was confirmed in BC<sub>4</sub>F<sub>4:5</sub> generation. In a PI 399073 x PI 408211B F<sub>4:5</sub> a different locus which conferred resistance to <i>P. sojae</i> isolate Butmu was identified adjacent to <i>Rps</i>8. This locus segregates as a single dominant gene and this region in this population was segregating in a Mendalian fashion. Male gametogenesis was evaluated in the parental genotypes and heterozygous lines at the <i>Rps</i>8 region. In the parent, PI 399073, a mix of abnormal meiotic products was observed. In selected heterozygous lines from one of the populations with segregation distortion, meiotic abnormalities as well as DNA in microcytes were observed. To summarize, in PI 399073, resistance to <i>P. sojae</i> on chromosome 13 could be comprised of more than one <i>Rps</i> gene and sequencing of this region will be crucial to elucidate its complexity. Markers linked with the two resistance loci can be used for the screening of breeding lines. Meiotic abnormalities may have contributed to the segregation distortion of <i>Rps</i>8 in the Williams x PI 399073 populations, however, further studies would be required to determine the meiotic fate of this genomic region. 2009 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1259772038 http://rave.ohiolink.edu/etdc/view?acc_num=osu1259772038 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
collection	NDLTD
language	English
sources	NDLTD
topic	Plant Pathology Soybean Phytophthora sojae stem and root rot chromosome 13 segregation distortion microsporogenesis microcytes molecular mapping graphical genotype ssr genotyping snp genotyping marker assisted selection disease resistance oomycete r genes
spellingShingle	Plant Pathology Soybean Phytophthora sojae stem and root rot chromosome 13 segregation distortion microsporogenesis microcytes molecular mapping graphical genotype ssr genotyping snp genotyping marker assisted selection disease resistance oomycete r genes Ortega, Maria Andrea Identification of Molecular Markers Associated with the <i>Rps</i>8 locus in Soybean and Evaluation of Microsporogenesis in <i>Rps</i>8/<i>rps</i>8 Heterozygous Lines
author	Ortega, Maria Andrea
author_facet	Ortega, Maria Andrea
author_sort	Ortega, Maria Andrea
title	Identification of Molecular Markers Associated with the <i>Rps</i>8 locus in Soybean and Evaluation of Microsporogenesis in <i>Rps</i>8/<i>rps</i>8 Heterozygous Lines
title_short	Identification of Molecular Markers Associated with the <i>Rps</i>8 locus in Soybean and Evaluation of Microsporogenesis in <i>Rps</i>8/<i>rps</i>8 Heterozygous Lines
title_full	Identification of Molecular Markers Associated with the <i>Rps</i>8 locus in Soybean and Evaluation of Microsporogenesis in <i>Rps</i>8/<i>rps</i>8 Heterozygous Lines
title_fullStr	Identification of Molecular Markers Associated with the <i>Rps</i>8 locus in Soybean and Evaluation of Microsporogenesis in <i>Rps</i>8/<i>rps</i>8 Heterozygous Lines
title_full_unstemmed	Identification of Molecular Markers Associated with the <i>Rps</i>8 locus in Soybean and Evaluation of Microsporogenesis in <i>Rps</i>8/<i>rps</i>8 Heterozygous Lines
title_sort	identification of molecular markers associated with the <i>rps</i>8 locus in soybean and evaluation of microsporogenesis in <i>rps</i>8/<i>rps</i>8 heterozygous lines
publisher	The Ohio State University / OhioLINK
publishDate	2009
url	http://rave.ohiolink.edu/etdc/view?acc_num=osu1259772038
work_keys_str_mv	AT ortegamariaandrea identificationofmolecularmarkersassociatedwiththeirpsi8locusinsoybeanandevaluationofmicrosporogenesisinirpsi8irpsi8heterozygouslines
_version_	1719428456769388544

Identification of Molecular Markers Associated with the <i>Rps</i>8 locus in Soybean and Evaluation of Microsporogenesis in <i>Rps</i>8/<i>rps</i>8 Heterozygous Lines

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