The tall wheatgrass-derived Fusarium head blight (FHB) resistance gene, Fhb7, was cloned from the decaploid species Thinopyrum ponticum and found to detoxify Fusarium-produced trichothecenes, such as deoxynivalenol (DON), in addition to conditioning Type II FHB resistance in wheat. Several Fhb7 resistance alleles have been integrated into the wheat D genome through 7D-7E translocations from diploid (Th. elongatum) and decaploid (Th. ponticum) tall wheatgrass that share the E genome containing the Fhb7 locus. Additionally, a Th. ponticum-derived Fhb7 resistance allele was transferred to the wheat A genome through 7A-7E translocation. The present study aimed to transfer the Th. elongatum-derived Fhb7 allele, designated Fhb7^The, to the wheat B genome by inducing meiotic homoeologous recombination between wheat chromosome 7B and Th. elongatum chromosome 7E, thereby making this FHB resistance allele Fhb7^The usable in common wheat as well as durum wheat breeding. In addition, Fhb7^The was characterized for its genomic structure and resistance to FHB in wheat. A small 7EL segment containing Fhb7^The was incorporated into wheat chromosome 7B by ph1b mutant-induced 7B-7E translocation. FHB evaluation of the 7B-7E translocation line and its wheat parental line ‘Chinese Spring’ indicated that Fhb7^The conditioned significant Type II resistance in the wheat background. Also, we found this translocation line does not contain the gene for yellow flour pigment, which is closely linked with the Fhb7 alleles from other sources. Thus, Fhb7^The can be utilized immediately in wheat breeding without obvious linkage drag. DNA sequence analysis identified 10 SNPs between Fhb7^The and the cloned Fhb7 allele, leading to seven amino acid differences between these two Fhb7 alleles. A user-friendly STS marker was developed specifically for Fhb7^The. Thereby, Fhb7^The is a new Fhb7 allele that conditions FHB resistance in wheat and can be deployed in both common and durum wheat varieties.

ACKNOWLEDGEMENT AND DISCLAIMER

This material is based upon work supported by the U.S. Department of Agriculture, under Award No. 2019-67013-35750 (NIFA) and Agreement No. 59-0206-7-002 (USWBSI). This is a cooperative project with the National Institute of Food and Agriculture and the U.S. Wheat & Barley Scab Initiative. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the view of the U.S. Department of Agriculture.