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ARS Home » Midwest Area » St. Paul, Minnesota » Plant Science Research » Research » Publications at this Location » Publication #111407
Title: PRODUCTION AND CHARACTERIZATION OF MAIZE-CHROMOSOME 9 RADIATION HYBRIDS DERIVED FROM AN OAT-MAIZE ADDITION LINE

Author
item RIERA LIZARAZU, OSCAR - UNIVERSITY OF MINNESOTA
item VALES, M - UNIVERSITY OF MINNESOTA
item ANANIEV, E - UNIVERSITY OF MINNESOTA
item Rines, Howard
item PHILLIPS, RONALD - UNIVERSITY OF MINNESOTA

Submitted to: Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/15/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary: Knowledge of the physical organization of the genetic make-up of our major cereal crop, corn, is needed to understand how the individual genes or components of the corn's genome (array of genetic material) function in growth and grain production. Such knowledge is key to modern breeding efforts to provide stable sustainable crop production and to tailor the crop for new market uses. We recently reported the recovery of novel partial hybrids between the cereals oat and corn in which portions of the corn's genetic material (one of its ten chromosomes) are added to the genetic material of oat. These materials allow analysis of the corn genome in segments isolated in an oat background. We have now succeeded in breaking up these corn chromosomes isolated individually in oat into numerous smaller pieces using irradiation with gamma rays. Using these procedures, we have derived a series of oat lines containing different small pieces of corn chromosome 9. By analyzing what corn genes or DNA sequences are present in each line and studying the patterns in which the sequences are retained, we can decipher how these genes are arrayed in the normal corn genome. Thus, these novel materials, termed oat-corn radiation hybrids, represent powerful tools for the numerous scientists working in the field of corn genomics and its application to corn genetic improvement.

Technical Abstract: In maize (Zea mays L., 2n=2x=20), map-based cloning and genome organization studies are often complicated because of the complexity of the genome. Maize-chromosome-addition lines of hexaploid cultivated oat (Avena sativa L., 2n=6x=42), where maize chromosomes can be individually manipulated, represent unique materials for maize genome analysis. Maize-chromosome addition lines are particularly suitable for the dissection of a single maize chromosome using radiation because cultivated oat is an allohexaploid in which multiple copies of the oat basic genome provide buffering to chromosomal aberrations and other mutations. In this study, we used irradiation (gamma rays at 30-, 40-, and 50-krad) of a monosomic maize- chromosome 9 addition line to produce novel oat lines possessing different fragments of maize-chromosome 9 including intergenomic translocations and modified maize addition chromosomes with internal and terminal deletions. Maize-chromosome 9 radiation hybrids (M9RHs) with one to ten radiation- induced breaks per chromosome were identified. We estimated that a panel of 100 informative M9RHs would allow the dissection of maize-chromosome 9 into approximately 200 regions with an average size of 0.5 to 1.0 Mb. Because mapping with maize chromosome addition lines and radiation hybrid derivatives involves assays for the presence or absence of a given marker, monomorphic markers can be quickly and efficiently mapped to chromosome region. Radiation hybrid derivatives also represent sources of region- specific DNA for cloning of genes or DNA markers and as source materials for the construction of physical maps of maize chromosomes.