Ryd4 Hb : a novel resistance gene introgressed from Hordeum bulbosum into barley and conferring complete and dominant resistance to the barley yellow dwarf virus

Abstract

Barley yellow dwarf virus (BYDV) causes high yield losses in most of the major cereal crops worldwide. A source of very effective resistance was detected within the tetraploid wild species of Hordeum bulbosum. Interspecific crosses between a resistant H. bulbosum accession and H. vulgare cv. 'Igri' were performed to transfer this resistance into cultivated barley. Backcrosses to H. vulgare resulted in offspring which carried a single subterminal introgression of H. bulbosum chromatin on barley chromosome 3HL and proved to be fully resistant to BYDV-PAV, as inferred by ELISA values of zero or close to zero and lack of BYDV symptoms. Genetic analysis indicated a dominant inheritance of the BYDV-PAV resistance factor, which we propose to denote Ryd4 ( Hb ) . The identity and effect of Ryd4 ( Hb ) are discussed in relation to other known genes for BYDV resistance or tolerance, as well as the relevance of this gene for resistance breeding in barley.

Pyramiding of Ryd2 and Ryd3 conferring tolerance to a German isolate of Barley yellow dwarf virus-PAV (BYDV-PAV-ASL-1) leads to quantitative resistance against this isolate

“…Ryd2 and Ryd3, are available for breeding of barley cultivars with quantitative BYDV resistance. In 2009, a gene for qualitative BYDV resistance in barley, named Ryd4 Hb , was identiWed and localised on chromosome 3HL (Scholz et al 2009). This resistance was introgressed from Hordeum bulbosum, the secondary gene pool of barley.…”

“…This resistance was introgressed from Hordeum bulbosum, the secondary gene pool of barley. According to Scholz et al (2009), this gene cannot yet be eYciently used in barley breeding because it is linked to undesirable traits derived from H. bulbosum. Therefore, actually using Ryd2 and Ryd3 in combination is the most promising way to breed barley cultivars expressing quantitative resistance against Barley yellow dwarf virus.…”

“…For this purpose, 0.1 g tissue of a mixed sample, of two leaves from half-way up the tiller, per plant was crushed and analysed by the double antibody sandwich (DAS) ELISA according to Clark and Adams (1977) with polyclonal antibodies against BYDV-PAV produced from isolate BYDV-PAV-ASL-1 (Serum bank of JKI) and used in many studies on BYDV-PAV, already (e.g. Scholz et al 2009). Extinction was measured at a wavelength of 405 nm using a microtitre plate reader (Opsys MR, ThermoLabsystems, Franklin USA).…”

Kapitel 2: Land- und Forstwirtschaft, Wasser, Ökosysteme und Biodiversität

“…Die geänderte Dynamik von Krankheiten und Schädlingen wird im mehrjährigen Selektionsprozess meist kontinuierlich berück-sichtigt. Zuletzt ist es zum Beispiel gelungen, aus der Wildart Hordeum bulbosum mittels konventioneller Züchtungsmetho-den ein hochwirksames Resistenzgen gegen die Viröse Gelbverzwergung in die Kulturgerste einzuführen (Scholz et al, 2009). Diese Krankheit tritt durch die wärmere Herbstwitterung verstärkt auf (Jungmeier, 2010 (Graiss et al, 2011).…”

The Effect of Homoeologous Meiotic Pairing in Tetraploid <b><i>Hordeum bulbosum</i></b> L. × <b><i>H. vulgare</i></b> L. Hybrids on Alien Introgressions in Offspring

“…Recently, Scholz et al [2009] succeeded in transferring a gene for resistance to barley yellow dwarf virus into H. vulgare ( Hv ). This resistance gene has been identified in the Hb accession A17 [Habekuss et al, 2004] and is the only resource so far causing complete resistance to this virus.…”