Cytogenetic and genomic characterization of a novel tall wheatgrass-derived Fhb7 allele integrated into wheat B genome

Authors: ZHANG, WEI - North Dakota State University; Danilova, Tatiana; MINGYI, ZHANG - North Dakota State University; REN, SHUANGFENG - North Dakota State University; ZHU, XIANWEN - North Dakota State University; ZHANG, QIJUN - North Dakota State University; ZHONG, SHAOBIN - North Dakota State University; Dykes, Linda; Fiedler, Jason; Xu, Steven; FRELS, KATHERINE - University Of Nebraska; WEGULO, STEPHEN - University Of Nebraska; Boehm Jr, Jeffrey; Cai, Xiwen

Submitted to: Journal of Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/17/2022
Publication Date: 10/6/2022
Citation: Zhang, W., Danilova, T.V., Mingyi, Z., Ren, S., Zhu, X., Zhang, Q., Zhong, S., Dykes, L., Fiedler, J.D., Xu, S.S., Frels, K., Wegulo, S., Boehm Jr, J.D., Cai, X. 2022. Cytogenetic and genomic characterization of a novel tall wheatgrass-derived Fhb7 allele integrated into wheat B genome. Journal of Theoretical and Applied Genetics. https://doi.org/10.1007/s00122-022-04228-3.
DOI: https://doi.org/10.1007/s00122-022-04228-3

Interpretive Summary: Fusarium head blight (FHB) is a devastating disease of wheat worldwide. Resistance plants have been considered the most effective tactic in managing this disease to reduce the economic losses in the wheat production and food industries. However, the shortage of effective resistance sources has limited the progress in breeding for FHB resistance in wheat, especially durum wheat used for pasta. In this study, ARS scientists identified and characterized a novel FHB-resistant Fhb7 gene derived from tall wheatgrass using molecular analyses. This FHB resistance gene from wild tall wheatgrass was incorporated into wheat, which made this new FHB resistance gene available of use in wheat breeding programs. DNA markers were also developed to aid application of this resistance gene in wheat variety/germplasm development. These advances will diversify and strengthen the defense of wheat against FHB disease.

Technical Abstract: A novel tall wheatgrass (Thinopyrum elongatum, genome EE)-derived Fhb7 allele, designated Fhb7The2, was identified and integrated into the wheat B genome through a small 7B-7E translocation (7BS·7BL-7EL) involving the terminal regions of the long arms. Fhb7The2 conditions significant Type II resistance to Fusarium head blight (FHB) in wheat. Integration of Fhb7The2 into the wheat B genome makes this wild species-derived FHB resistance gene usable for breeding in both common and durum wheat. By contrast, other Fhb7 introgression lines involving wheat chromosome 7D can be utilized only in common wheat breeding programs, not in durum wheat. Additionally, we found that Fhb7The2 does not have the linkage drag of the yellow flour pigment gene that is tightly linked to the decaploid Th. ponticum-derived Fhb7 allele Fhb7Thp. This will further improve the utility of Fhb7The2 in wheat breeding. DNA sequence analysis identified 12 single nucleotide polymorphisms (SNPs) in Fhb7The2, Fhb7Thp, and another Th. elongatum-derived Fhb7 allele Fhb7The1, which led to seven amino acid conversions in Fhb7The2, Fhb7Thp, and Fhb7The1, respectively. However, no significant variation was observed in their predicted protein configuration as a glutathione transferase. Diagnostic DNA markers were developed specifically for Fhb7The2. The 7EL segment containing Fhb7The2 in the translocation chromosome 7BS·7BL-7EL exhibited a monogenic inheritance pattern in the wheat genetic background. This will enhance the efficacy of marker-assisted selection for Fhb7The2 introgression, pyramiding, and deployment in wheat germplasm and varieties.