Analysis of sugarcane mosaic virus resistance in maize in an isogenic dihybrid crossing scheme and implications for breeding potyvirus-resistant maize hybrids

Abstract

The gene action of 2 sugarcane mosaic virus (SCMV) resistance loci in maize, Scmv1 and Scmv2, was evaluated for potyvirus resistance in an isogenic background. All 4 homozygous and 5 heterozygous isogenic genotypes were produced for introgressions of the resistant donor (FAP1360A) alleles at both loci into the susceptible parent (F7) genetic background using simple sequence repeat markers. For SCMV and maize dwarf mosaic virus (MDMV), virus symptoms appeared rapidly in the 3 homozygous genotypes, with susceptibility alleles fixed at 1 or both loci. Although the 9 isogenic genotypes revealed a high level of resistance to Zea mosaic virus (ZeMV), the same 3 homozygous genotypes were only partially resistant. This indicates that 1 resistance gene alone is not sufficient for complete resistance against SCMV, MDMV, and ZeMV. Scmv1 showed strong early and complete dominant gene action to SCMV, but it gradually became partially dominant. Scmv2 was not detected at the beginning, showing dominant gene action initially and additive gene action at later stages. Both genes interacted epistatically (for a high level of resistance, at least 1 resistance allele at each of both loci is required). This implies that double heterozygotes at the 2 loci are promising for producing SCMVresistant hybrids. Results are discussed with respect to prospects for isolation of SCMV and MDMV resistance genes.

Combined linkage and association mapping reveals candidates for Scmv1, a major locus involved in resistance to sugarcane mosaic virus (SCMV) in maize

“…The Scmv1 region has been reported to associate with resistance to other members of the Potyviridae family, including WSMV and MDMV [44,45]. The near isogenic line F7 RR/RR , which was used as a resistant parental line in this study, was also found to be resistant to MDMV and ZeMV [28]. According to a model proposed by Kou [46], a single gene conferring BSR may function in either basal-resistance pathways, in overlapping pathways that confer race-specific resistances, or at sites of cross-talk between different defense pathways.…”

“…Apart from being influenced by two major genes, resistance of maize to SCMV is also affected by genetic background and various environmental factors [13,17,18]. To obtain reliable phenotypic data, we developed a F 2 mapping population from a near-isogenic pair where the resistance allele was fixed at the Scmv2 locus, and only Scmv1 was segregating [28]. Furthermore, selection of only susceptible individuals from the F 2 population for fine-mapping of the Scmv1 locus reduced the possibility of misclassification, as heterozygotes tend to be more plastic in their response to SCMV inoculation.…”

Genetic Analysis of Sugarcane mosaic virus Resistance in the Wisconsin Diversity Panel of Maize

“…Ingvardsen et al (2010) mapped Scmv2 to a 0.28-cM region covering 1.3 Mb and suggested several candidate genes in that region of chromosome 3. Multiple studies have shown that Scmv1/Mdm1 contributes to resistance at all developmental stages after infection, whereas Scmv2 has been associated with sustained resistance several weeks after exposure to the virus (Dußle et al, 2000;Xing et al, 2006). Although these two loci have repeatedly been associated with resistance, the amount of phenotypic variation explained by Scmv1/ Mdm1 and Scmv2 has varied by population studied.…”

Auxin Binding Protein 1 Reinforces Resistance to Sugarcane Mosaic Virus in Maize

“…1, hypothetical protein; 2, putative uncharacterized protein; 3, glutathione synthetase; 4, auxin binding protein 1; 5, unknown. active at later stages post SCMV infection (Xia et al, 1999;Xing et al, 2006). We characterized allelic ZmABP1 promoter activity for FAP1360A and F7 using maize protoplast transient expression assays.…”