High-resolution mapping ofRyd4^Hb, a major resistance gene toBarley yellow dwarf virusfromHordeum bulbosum

Abstract

Virus diseases are causing high yield losses in crops worldwide. The Barley yellow dwarf virus (BYDV) complex is responsible for one of the most widespread and economically important viral diseases of cereals. While no complete resistance gene has been uncovered in the primary genepool of barley, sources of resistance were identified in the wild relative Hordeum bulbosum, representing the secondary genepool of barley. One such locus, Ryd4Hb, has been previously introgressed into barley, and was allocated to chromosome 3H, but is tightly linked to a sublethality factor that prevents the incorporation and utilization of Ryd4Hb in barley varieties. To solve this problem, we fine-mapped Ryd4Hb and separated it from this negative factor. We narrowed the Ryd4Hb locus to a 66.5 kbp physical interval in the barley 'Morex' reference genome. The region comprises one complete and one partial gene from the nucleotide-binding and leucine-rich repeat immune receptor family, typical of dominant virus resistance genes. The closest homolog to these two Ryd4Hb candidate genes is the wheat Sr35 stem rust resistance gene. In addition to the fine mapping, we reduced the sublethality factor interval to 600 kbp in barley. Aphid feeding experiments demonstrated that Ryd4Hb provides a direct resistance to BYDV rather than a resistance to its vector. The presented results, including the high-throughput molecular markers, will permit a more targeted selection of the resistance in breeding, enabling the use of Ryd4Hb in barley varieties.

Fine mapping a QTL for BYDV-PAV resistance in maize

“…Barley Yellow Dwarf (BYD) is one of the economically most important diseases in small grain cereals (Choudhury et al 2017; van den Eynde et al 2020). Due to increasing autumn and winter temperatures, it is expected that BYD will become an increasing problem (Pidon et al 2023). For maize, BYD infection has a direct negative effect on different phenotypic characters (Beuve et al 1999;Loi et al 2004;Panayotou 1977).…”

“…Ryd4 Hb was introgressed into cultivated barley from the wild relative H. bulbosum and was not used in breeding programs because of linkage drag with a recessive sublethality factor (Scholz et al 2009). Recently, Ryd4 Hb was ne-mapped to a 66.5 kbp physical interval in the barley 'Morex' reference genome that comprises one complete and one partial gene from the nucleotide-binding and leucine-rich repeat immune receptor family (Pidon et al 2023). Additional QTL for tolerance to BYD-PAV and BYDV-RPV were mapped to chromosomes 1H, 2H, 4H, and 7H of barley (del Blanco et al 2014; Kraakman et al 2006;Scheurer et al 2001;Toojinda et al 2000).…”

Possibilities of using the tetraploid interspecific hybrid <i>Hordeum bulbosum</i> L. × <i>Hordeum vulgare</i> L. in obtaining new recombinant barley lines

“…Образцы H. bulbosum характеризуются рядом ценных признаков, таких как устойчивость к мучнистой росе, стеблевой и листовой ржавчине, вирусам BaMMV, BaYMV и BYDV (Jones, Pickering, 1978;Michel, 1996;Habekuß et al 2004). Показана возможность их переноса от образцов H. bulbosum в геном H. vulgare при межвидовой гибридизации (Jones, Pickering, 1978;Michel, 1996;Ruge et al, 2003;Ruge-Wehling et al, 2006;Scholz et al, 2009;Hoseinzadeh et al, 2020;Pidon et al, 2021;2023;Yu et al, 2018;2022). На основе межвидовых гибридов между H. vulgare и H. bulbosum получены серии интрогрессивных линий (Johnston et al, 2009;Pickering, 1991;Pickering et al 1994;Pickering et al, 2000;Zhang et al, 2001;Scholz et al, 2009;Pendinen et al, 2018).…”