Genetic Analysis And Molecular Mapping Of Crown Rust Resistance Genes In Oat(Avena Sativa L.)

Crown rust,caused by Puccinia coronata f.sp.avenae Eriks.(Pca),is the most important oat disease resulting in great yield losses in many growing regions.The cultivars with host resistance is recognized as the most effective and economical method to manage this disease.Based on the present production reality,to find elite oat germplasms which can be used directly in oat breeding programs against to the current crown rust populations and identifying resistance genes in them by modern biotechnologies is important.Accordding to the previous studies,the oat cultivars AC Assiniboia and AC Medallion,the materials MN841801 and Temp?Pc98 are effectively resistant to most current crown rust races in Canada.At present study,we constructed several bi-parental populations to conduct the genetic analysis of these oat germplasms.And created high density molecular marker linkage maps for these resistance genes using GBS and oat 6K SNP chips.Finally we finished the molecular mapping of all resistance genes detected in this study by newly developed SNP and KASP markers.The genes identified and mapped in this study are effective gene sources for the future oat resistant breeding.The main results at present study are as follows:1.Genetic analysis and molecular mapping of the oat crown rust seedling resistance gene Pc39Two RIL mapping populations AC Assiniboia/MN841801(Asb MN)and AC Medallion/MN841801(Med MN),which have different backgrounds,were created between Pc39 donor parents AC Assiniboia and AC Medallion and the susceptible parent MN841801.Both populations and the parental lines were inoculated with oat crown rust race LMBG for seedling resistant phenotypic data collection.The results showed that seedling resistance in AC Assiniboia and AC Medallion aimed at race LMBG was controlled by gene Pc39,which was consistent with previous study.Two linkage maps of Pc39 were constructed using GBS and6K SNP chip combined with phenotypes.Gene Pc39 was co-localized with marker GMI?ES01?c12570?390?kom235.Based on the oat consensus map,the resistance gene Pc39was located at 3.7 c M of the oat chromosome 1C linkage group Mrg11.Sixteen Pc39-linked SNPs were selected for KASP marker development and validated in a panel of 74 North America oat lines,the result indicated that KASP markers GMI?ES15?c6153?392?kom239and GMI?ES01?c12570?390?kom235 will be useful for Marker-Assisted-Selection of Pc39in oat breeding program.2.Genetic analysis and molecular mapping of the oat crown rust seedling resistance gene Pc38Two RIL populations with different backgrounds(Asb MN and Med MN)were created using the resistant parents AC Assiniboia and AC Medallion that containing Pc38 and the susceptible parent MN841801.Both populations and the parental lines were inoculated with several oat crown rust races(DHBB,LHBB,NHBL and BHCC)for seedling resistant phenotypic data collection.The results showed that seedling resistance in AC Assiniboia and AC Medallion against to above-mentioned races was controlled by gene Pc38,which was consistent with previous study.Two linkage maps of Pc38 were created using GBS and 6K SNP chip combined with phenotypes.Gene Pc38 was co-segregated with two markers GMI?ES14?c2753?587?Kom224 and GMI?ES05?c2343?456?Kom225.According to the oat consensus map,the resistance gene Pc38 was mapped at 112 c M of the oat consensus map linkage group Mrg33.Fifteen Pc38-linked SNPs were selected for developing KASP markers and successfully validated in both populations for distinguishing progenies with and without Pc38.3.Genetic analysis and molecular mapping of a seedling crown rust resistance gene PcMNThree RIL mapping populations Asb MN,Med MN and Makuru/MN841801(Mak MN)that have different backgrounds were developed between the resistant parent MN841801 and three susceptible parents AC Assiniboia,AC Medallion and Makuru.All populations and the parental lines were inoculated using several oat crown rust races(BRBB,JTQQ,JTTG and JTQG)for identifying seedling resistant phenotypes.The results showed that seedling resistance in MN841801 against to above-mentioned races was controlled by a single gene,which is a broad spectrum resistance gene,temporarily designated as PcMN.Three linkage maps of PcMN were developed using GBS and 6K SNP chip combined with phenotypes.Gene PcMN co-segregating with two markers avgbs?cluster?4215.1.58?kom300 and avgbs?cluster?4215.1.59?kom301.Gene PcMN was located at 61 c M of the oat chromosome9D linkage group Mrg02 according to the oat concensus map.Eighteen PcMN-linked SNPs were selected for KASP marker development and validated in a diverse set of 75 North America oat lines,the result indicated that KASP markers GMI?ES05?c14633?290?kom293and avgbs2?184685.1.35 will be useful for MAS of gene PcMN.There is no enhanced resistance between PcMN and the APR QTL QPc.crc-14D in MN841801.4.Genetic analysis and molecular mapping of a seedling crown rust resistance gene Pc98Two F_2:3 populations(Temp?Pc98/Bingo and Temp?Pc98/Kasztan)with different backgrounds were constructed between resistant parent Temp?Pc98,which was derived from the cross of Avena sterilis L accession CAV1979 and cultivated oat,and the susceptible parents Bingo and Kasztan.The F₁,F₂ generation and F_2:3 progenies as well as the parental lines were inoculated with oat crown rust race DSGB for seedling resistant phenotypes collection.The results showed that seedling resistance in Temp?Pc98 aimed at race DSGB was controlled by a single dominant gene,officially designated as Pc98.Two linkage maps of Pc98 were constructed using GBS and 6K SNP chip combined with phenotypes.Gene Pc98 was co-localized with markers GMI?ES02?lrc33175?496?kom372,GMI?ES02?lrc18492?57?kom373,avgbs2?153634.1.45?kom406 and avgbs 2?153634.1.46?kom 409.According to the oat consensus map,the resistance gene Pc98was mapped at 251 cM of the oat consensus map linkage group Mrg20.Twenty Pc98-linked SNPs were selected for KASP marker development and validated in a panel of 79 North America oat lines,the result indicated that KASP markers GMI?DS?LB?7494?kom370 and avgbs2?153634.1.59?kom 410 are recommended for MAS of gene Pc98 in the future breeding program.