QSbm.ubo - 2BS=Sbm2, a major QTL controlling the response to Soil - Borne Cereal Mosaic Virus (SB CMV) in durum wheat, was c haracterized in two recombinant inbred line populations, namely Meridiano (resistant, R) x Claudio (moderately susceptible, MS) and Simeto (susceptible, S) x Levante (R). B y means of meta - QTL analysis QSbm.ubo - 2BS was mapped as a unique QTL within a 2 cM - wide interval (LOD - 2) in the distal region of chromosome arm 2BS (Maccaferri et al., 2012) . The addition of the Illumina 90K SNPs array to the durum linkage maps allowed to identify 36 transcripts - associated SNPs tightly associated with the Mendelized QTL (Maccaferri et al., 2014) . Nine SNPs from the Illumina 90K wheat array were converted to KASP markers, which provided fluorescent high - throughput assays spanning the QTL region. Marker - assisted selection (MAS) was performed on ∼ 2,000 RILs from the Svevo (R) x Ciccio (S) population (Gadaleta et al., 2009) with two KAS P markers flanking the QTL interval , KUBO 9 and KUBO 13. MAS identified 291 lines recombinant between the two markers. These lines were characterized for SBCMV response in the 2016 field nursery under severe and uniform SBCMV infection. The lines were scor ed for symptom severity (SS) on a 0 to 4 scale , where 0 = very res istant and 4 = very susceptible (Vallega and Rubies Autonell, 1985). They were also genotyped with seven KASP markers distributed along the QTL interval ( KUBO 1 , KUBO 3 , KUBO 27 , KUBO 29 , KU BO 38, KUBO 40 and KUBO 41 ) and with the DArT marker wPt - 2106 , the marker most associated with the phenotype in the Meridiano x Claudio RIL population (Maccaferri et al., 2012). The bimodal distribution of SS reflects the segregation of the resistance trai t in the QTL interval: frequency peaks were observed around values of 1.7 and 3.8. The fine - mapping allowed to narrow the most probable support interval to 0,2 cM between KUBO 27 and KUBO 1 based on the Svevo x Ciccio RILs population. Work is in progress to analyze other - 1,000 RILs of the same population in order to confirm the results obtained with the first part of the study and to improve the ongoing fine - mapping of the gene responsible for the resistance.
FINE-MAPPING OF QSBM.UBO-2BS=SBM2, A MAJOR QTL FOR RESISTANCE TO SOIL-BORNE CEREAL MOSAIC VIRUS (SBCMV)
BRUSCHI, MARTINA;MACCAFERRI M.
;SCIARA G.;ORMANBEKOVA D.;CORNETI S.;STEFANELLI S.;RATTI C.;GADALETA, ANNALISA;TUBEROSA R.
2017
Abstract
QSbm.ubo - 2BS=Sbm2, a major QTL controlling the response to Soil - Borne Cereal Mosaic Virus (SB CMV) in durum wheat, was c haracterized in two recombinant inbred line populations, namely Meridiano (resistant, R) x Claudio (moderately susceptible, MS) and Simeto (susceptible, S) x Levante (R). B y means of meta - QTL analysis QSbm.ubo - 2BS was mapped as a unique QTL within a 2 cM - wide interval (LOD - 2) in the distal region of chromosome arm 2BS (Maccaferri et al., 2012) . The addition of the Illumina 90K SNPs array to the durum linkage maps allowed to identify 36 transcripts - associated SNPs tightly associated with the Mendelized QTL (Maccaferri et al., 2014) . Nine SNPs from the Illumina 90K wheat array were converted to KASP markers, which provided fluorescent high - throughput assays spanning the QTL region. Marker - assisted selection (MAS) was performed on ∼ 2,000 RILs from the Svevo (R) x Ciccio (S) population (Gadaleta et al., 2009) with two KAS P markers flanking the QTL interval , KUBO 9 and KUBO 13. MAS identified 291 lines recombinant between the two markers. These lines were characterized for SBCMV response in the 2016 field nursery under severe and uniform SBCMV infection. The lines were scor ed for symptom severity (SS) on a 0 to 4 scale , where 0 = very res istant and 4 = very susceptible (Vallega and Rubies Autonell, 1985). They were also genotyped with seven KASP markers distributed along the QTL interval ( KUBO 1 , KUBO 3 , KUBO 27 , KUBO 29 , KU BO 38, KUBO 40 and KUBO 41 ) and with the DArT marker wPt - 2106 , the marker most associated with the phenotype in the Meridiano x Claudio RIL population (Maccaferri et al., 2012). The bimodal distribution of SS reflects the segregation of the resistance trai t in the QTL interval: frequency peaks were observed around values of 1.7 and 3.8. The fine - mapping allowed to narrow the most probable support interval to 0,2 cM between KUBO 27 and KUBO 1 based on the Svevo x Ciccio RILs population. Work is in progress to analyze other - 1,000 RILs of the same population in order to confirm the results obtained with the first part of the study and to improve the ongoing fine - mapping of the gene responsible for the resistance.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
