Work

Identification of the QBB.hau-4A candidate gene for black point resistance in bread wheat

Year: 2026

Type: article

Abstract: Black point (BP) disease affects wheat ( Triticum aestivum ) production worldwide, and identifying BP resistance genes is essential for developing resistant cultivars. We previously detected QBB.hau-4A , a major QTL for BP resistance, using the fungal pathogen Bipolaris sorokiniana with a recombinant inbred line (RIL) population from a cross between wheat lines Wanyuanbai 1 and SN4143. Here, we fine mapped QBB.hau-4A using secondary F 2 and F 2:3 populations derived from resistant and susceptible RILs. Using 14 dCAPS markers, the QTL was delimited to a 1.36 Mb interval. With gene-specific markers, we narrowed this interval to a 1.06 Mb region between markers BP-100-d1 and BP-4A-d34 (40.87–41.93 Mb), containing six high-confidence genes in the Chinese Spring reference genome. Based on parental expression patterns and sequence polymorphisms, we identified four candidate genes for QBB.hau-4A : TraesCS4A02G050400 , TraesCS4A02G050500 , TraesCS4A02G050700 , and TraesCS4A02G050800 . Of these, TraesCS4A02G050800 is the most likely candidate for QBB.hau-4A . We developed BP-800-d1 , a gene-specific marker for TraesCS4A02G050800 based on a SNP and an InDel distinguishing the resistant and susceptible parents. This marker was subsequently validated in two F 2 populations and a diverse panel of 412 wheat accessions. To our knowledge, this study represents one of the first efforts to identify candidate genes associated with BP resistance. In addition to offering valuable information for understanding the complex genetic basis of BP resistance, it provides molecular markers for breeders.

Source: The Crop Journal

DOI: 10.1016/j.cj.2026.04.001