Barley Yellow Mosaic Virus VPg Is the Determinant Protein for Breaking eIF4E-Mediated Recessive Resistance in Barley Plants

Abstract

In this study, we investigated the barley yellow mosaic virus (BaYMV, genus Bymovirus) factor(s) responsible for breaking eIF4E-mediated recessive resistance genes (rym4/5/6) in barley. Genome mapping analysis using chimeric infectious cDNA clones between rym5-breaking (JT10) and rym5-non-breaking (JK05) isolates indicated that genome-linked viral protein (VPg) is the determinant protein for breaking the rym5 resistance. Likewise, VPg is also responsible for overcoming the resistances of rym4 and rym6 alleles. Mutational analysis identified that amino acids Ser-118, Thr-120, and His-142 in JT10 VPg are the most critical residues for overcoming rym5 resistance in protoplasts. Moreover, the rym5-non-breaking JK05 could accumulate in the rym5 protoplasts when eIF4E derived from a susceptible barley cultivar was expressed from the viral genome. Thus, the compatibility between VPg and host eIF4E determines the ability of BaYMV to infect barley plants.

Application of a Reverse Genetic System for Beet Necrotic Yellow Vein Virus to Study Rz1 Resistance Response in Sugar Beet

“…A high selection pressure conferred by single resistance genes favor the development of resistance-breaking mutations that become dominant in the virus population. Several resistance-breaking events have been reported in the past for important host-virussystems like barley-barley yellow mosaic virus (Li et al, 2016), rice-rice yellow mottle virus (Pinel-Galzi et al, 2016), and tomato-tomato spotted wilt virus (Batuman et al, 2017). Therefore, a continuous observation of virus populations is required in order to identify new mutations, which need to be tested subsequently for their resistance-breaking ability.…”

High-resolution mapping ofRym14Hb, a wild relative resistance gene to barley yellow mosaic disease

“…The rym4 allele provides resistance to BaMMV and to the common BaYMV pathotype BaYMV-1, but not to pathotype BaYMV-2, which emerged in Europe at the end of the 1980s (Adams et al 1987;Huth 1989;Adams 1991;Graner and Bauer 1993;Steyer et al 1995). The spectrum of rym5 covers also BaYMV-2, however, resistance-breaking isolates of BaMMV and BaYMV have emerged (Kanyuka et al 2004;Habekuß et al 2008;Li et al 2016). Facing the prospect of boom-and-bust cycles for known resistance genes (Brown and Tellier 2011), it is critical to continue searching for alternative resistance loci to underpin resistance breeding and to allow pyramiding of disease resistance loci.…”

The apparent non‐host resistance of Ethiopian mustard to a radish‐infecting strain of Turnip mosaic virus is largely determined by the C‐terminal region of the P3 viral protein

“…The phenotype of the resistance provided by these eIF‐related recessive resistance alleles resembles the apparent immunity of the NHR, pointing to a possible involvement of eIF mediators, but this extreme requires further confirmation. An argument against the involvement of eIFs mediating NHR in Ethiopian mustard is that the identified viral counterpart of these factors in the Potyviridae is the genome‐linked protein VPg (Gallois et al ., ; Li et al ., ; Perez et al ., ; Tavert‐Roudet et al ., ), whereas the viral determinant identified in this work is the viral P3. However, this is an indirect argument, requiring further verification.…”