High‐resolution mapping of the pericentromeric region on wheat chromosome arm 5AS harbouring the Fusarium head blight resistance QTLQfhs.ifa‐5A

Abstract

SummaryThe Qfhs.ifa‐5A allele, contributing to enhanced Fusarium head blight resistance in wheat, resides in a low‐recombinogenic region of chromosome 5A close to the centromere. A near‐isogenic RIL population segregating for the Qfhs.ifa‐5A resistance allele was developed and among 3650 lines as few as four recombined within the pericentromeric C‐5AS1‐0.40 bin, yielding only a single recombination point. Genetic mapping of the pericentromeric region using a recombination‐dependent approach was thus not successful. To facilitate fine‐mapping the physically large Qfhs.ifa‐5A interval, two gamma‐irradiated deletion panels were generated: (i) seeds of line NIL3 carrying the Qfhs.ifa‐5A resistance allele in an otherwise susceptible background were irradiated and plants thereof were selfed to obtain deletions in homozygous state and (ii) a radiation hybrid panel was produced using irradiated pollen of the wheat line Chinese Spring (CS) for pollinating the CS‐nullisomic5Atetrasomic5B. In total, 5157 radiation selfing and 276 radiation hybrid plants were screened for deletions on 5AS and plants containing deletions were analysed using 102 5AS‐specific markers. Combining genotypic information of both panels yielded an 817‐fold map improvement (cR/cM) for the centromeric bin and was 389‐fold increased across the Qfhs.ifa‐5A interval compared to the genetic map, with an average map resolution of 0.77 Mb/cR. We successfully proved that the RH mapping technique can effectively resolve marker order in low‐recombining regions, including pericentromeric intervals, and simultaneously allow developing an in vivo panel of sister lines differing for induced deletions across the Qfhs.ifa‐5A interval that can be used for phenotyping.

Fine-mapping of the Fusarium head blight resistance QTL Qfhs.ifa-5A identifies two resistance QTL associated with anther extrusion

“…Qfhs.ifa - 5A (Buerstmayr et al 2002 , 2003 ) is among the most frequently studied resistance QTL and was validated either individually or in combination with other QTL (Bokore et al 2017 ; Chen et al 2006 ; Chrpova et al 2011 ; Kang et al 2011 ; McCartney et al 2007 ; Salameh et al 2011 ; Suzuki et al 2012 ; Tamburic-Ilincic 2012 ; von der Ohe et al 2010 ). Qfhs.ifa - 5A mapped across the centromere of chromosome 5A within a 1.6 cM QTL support interval flanked by the SSR markers barc186 and wmc805 (Buerstmayr et al 2003 , 2018 ). However, based on the IWGSC RefSeq v1.0 (International Wheat Genome Sequencing Consortium [IWGSC] et al 2018 ) this interval comprises more than 300 Mbp.…”

“…High-resolution mapping of the pericentromeric region of chromosome 5A identified 70 lines that recombined in the Qfhs.ifa - 5A interval (Buerstmayr et al 2018 ). These NILs were phenotyped for FHB resistance in field trials to precisely locate the QTL and pave the way for the ultimate goal of positional cloning resistance underlying gene(s).…”

Showcasing the application of synchrotron‐based X‐ray computed tomography in host–pathogen interactions: The role of wheat rachilla and rachis nodes in Type‐II resistance to Fusarium graminearum

“…Seven wheat genotypes were selected for the study: CDC Alsask (a hard red spring wheat cultivar), 04GC0139 (a resistant donor of Fhb1 , Fhb2 , and Fhb5 QTLs/genes), four NILs (carrying less than 4% alleles from the resistance donor) in a CDC Alsask background (Alsask2, Alsask8, Alsask22, and Alsask25) segregating for Fhb1 , Fhb2 , and Fhb5 , and a putative intergeneric spring wheat line 00Ar134‐1 (Table ). The presence of genes was confirmed using molecular markers: umn10 , gwm493 , and gwm533 ; functional markers for the pore‐forming toxin (PFT) protein in Fhb1 ; and single nucleotide polymorphisms markers from Zhao et al () in Fhb1 region: wmc105 , wmc152 , wmc397 , wmc398 , and gwm644 flanking Fhb2 and wmc705 , barc117 , gwm293 , gwm304 , gwm415 , barc180 , barc186 , and Ra_c23129_348 (single nucleotide polymorphism marker) flanking Fhb5 (Buerstmayr et al, ; McCartney et al, ; Rawat et al, ; Zhao et al, ). The line 00Ar134‐1 is derived from a cross of wheat and Elymus repens L. (wheatgrass) and was included as it has a good level of resistance to FHB (Brar & Hucl, ).…”

“…Fhb5 (Buerstmayr et al, 2017;McCartney et al, 2004;Rawat et al, 2016;Zhao et al, 2018). The line 00Ar134-1 is derived from a cross of wheat and Elymus repens L. (wheatgrass) and was included as it has a good level of resistance to FHB (Brar & Hucl, 2017).…”

Biotechnological and Digital Revolution for Climate-Smart Plant Breeding

“…Recent studies report the molecular characterization of QTLs together with the identification of DNA polymorphisms underlying important traits, such as resistance to drought in barley and FHB resistance in wheat [74][75][76]. A large number of QTLs have been identified in cereals for agronomic and physiological traits under heat temperature and water stress conditions.…”