Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/5/2006
Publication Date: 2/1/2007
Citation: Jones, M.W., Redinbaugh, M.G., Louie Jr, R. 2007. The Mdml Locus and Maize Resistance to Maize Dwarf Mosaic Virus. Plant Disease. 91:185-190. Interpretive Summary: Maize dwarf mosaic is a viral disease of corn that occurs world-wide and is most frequently controlled by the use of virus-resistant hybrids. A single dominant gene called Mdm1 controls resistance to the virus that causes the disease (Maize dwarf mosaic virus or MDMV) the inbred corn line Pa405. The same gene, or genes located nearby on the same chromosome, control resistant to two related viruses: Sugarcane mosaic virus (SCMV) and Wheat streak mosaic virus (WSMV). We characterized resistance to MDMV and SCMV in 115 maize lines. In 42 out of 43 maize lines tested, resistance to MDMV was associated with the same region of the maize chromosome as in Pa405. These data will be useful to corn breeders who want to incorporate resistance to these destructive viruses into hybrids they are developing. This work will be used by research scientists and plant breeders to develop resistant corn hybrids to control diseases caused by maize dwarf mosaic virus and sugarcane mosaic virus.
Technical Abstract: Previously, Mdm1, a gene controlling resistance to Maize dwarf mosaic virus (MDMV) was identified in the inbred line Pa405. The gene was tightly linked to the RFLP marker umc85 on the short arm of chromosome 6. This chromosomal region is also the location of resistance genes to two other viruses in the family Potyviridae: Sugarcane mosaic virus (SCMV) and Wheat streak mosaic virus (WSMV). A diverse collection of 115 maize inbred lines was evaluated for resistance to MDMV and SCMV, and for MDMV resistance loci on chromosome 6S. Forty-six resistant inbred lines were crossed to three MDMV-susceptible inbred lines to develop F2 populations. The F2 populations were inoculated with MDMV and scored for infection and symptom type. Environmental factors influenced both the rate and type of symptom development. Bulked segregant analysis of each F2 population indicated that, in 42 of 43 MDMV resistant lines, chromosome 6S markers found in the resistant parent were also present in the bulked resistant, but not the susceptible, tissue. Markers previously associated with resistance to both SCMV and WSMV on chromosome 3 and to WSMV on chromosome 10 were associated with resistance in 9 and 7 of the F2 populations, respectively. These data suggest that Mdm1 or closely linked genes on chromosome 6S are associated with MDMV resistance in most germplasm, but that other loci may also affect resistance. IMPACT STATEMENT: This work will be used by research scientists and plant breeders to develop resistant corn hybrids to control diseases caused by maize dwarf mosaic virus and sugarcane mosaic virus.