Title: Genetic analysis of resistance to six virus diseases in a multiple virus-resistant maize inbred line Authors
Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 1, 2014
Publication Date: April 1, 2014
Citation: Zambrano, J.L., Jones, M.W., Brenner, E., Francis, D.M., Tomas, A., Redinbaugh, M.G. 2014. Genetic analysis of resistance to six virus diseases in a multiple virus-resistant maize inbred line. Theoretical and Applied Genetics. 127(4):867-880. Interpretive Summary: Virus diseases in corn can cause severe yield reductions that threaten crop production and food supplies around the world. Genetic resistance to different viruses is the most economical and environmentally sustainable approach for controlling these diseases in corn and other crops. Resistance to individual viruses has been found in different corn lines, and has been mapped to specific locations on different corn chromosomes. Interestingly, virus resistance in to several different viruses seems to be found in the same chromosomal locations in these different corn lines. However, we could not tell if the resistance genes were in the same locations without having them all in the same corn line. Several years ago, we developed an inbred corn line called Oh1VI that is resistant to at least ten viruses in five different virus families. We crossed this line to another corn line that is susceptible to the ten viruses, and examined segregation of the responses to six viruses in the progeny to identify resistance genes. We found 17 genes for virus resistance in Oh1VI, with each different virus having one to three resistance genes. Of these 17 genes, 15 were clustered in small regions of chromosomes 2, 3, 6, and 10. Because the resistance genes are so closely linked, Oh1VI and lines derived from it could help corn breeders to develop multi-virus resistant crops.
Technical Abstract: Virus diseases in maize can cause severe yield reductions that threaten crop production and food supplies in some regions of the world. Genetic resistance to different viruses has been characterized in maize populations under diverse environments and screening techniques, and resistance loci have been mapped to all maize chromosomes. The maize inbred line, Oh1VI, is resistant to at least 10 viruses, including viruses in five different families. To determine the genes and inheritance mechanisms responsible for the multiple virus resistance in this line, F1 hybrids, F2 progeny and a recombinant inbred line (RIL) population derived from a cross of Oh1VI and the virus-susceptible inbred line Oh28 were evaluated. Progeny were screened for their responses to Maize dwarf mosaic virus, Sugarcane mosaic virus, Wheat streak mosaic virus, Maize chlorotic dwarf virus, Maize fine streak virus, and Maize mosaic virus. Depending on the virus, dominant, recessive, or additive gene effects were responsible for the resistance observed in the F1. For all viruses, one, two or three gene models explained the observed segregation of resistance in the F2 generation. Composite interval mapping in the RIL population identified 17 resistance QTLs associated with the six viruses. Of these, 15 were clustered in specific regions of chromosomes 2, 3, 6, and 10. It is unknown whether these regions of clustered QTLs contain single or multiple virus resistance genes, but the coupling phase linkage of genes conferring resistance to multiple virus diseases in this population could facilitate breeding efforts to develop multi-virus resistant crops.