ARS | Publication request: COMPARATIVE ANALYSIS OF A ONE-MEGABASE SEQUENCE SPANNING THE MAIZE RF1 FERTILITY RESTORER WITH THE RICE GENOME

Submitted to: Maize Genetics Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: January 10, 2004
Publication Date: March 10, 2004
Citation: Kronmiller, B., Gobelman Werner, K.S., Wise, R.P. 2004. Comparative analysis of a one-megabase sequence spanning the maize Rf1 fertility restorer with the rice genome. 46th Maize Genetics Conference. p. 112.

Technical Abstract: In T-cytoplasm maize, cytoplasmic male sterility (CMS) is attributed to the presence of the unique mitochondrial gene, T-urf13. Full suppression of T-urf13-mediated CMS is directed by the combined action of dominant alleles of the nuclear (fertility restorer) genes, rf1 and rf2. As a first step in the positional cloning of the rf1 gene, one-megabase of maize chromosome 3 spanning the rf1 locus was sequenced and annotated. Three B73 BAC libraries were used to create a physical map of 439 clones anchored to the rf1 locus. A minimum-tiling path of 12 sequenced BACs comprise 79% transposable elements as well as other repetitive sequences, including centromeric-specific repeats. One-hundred fourteen unique gene families from the megabase maize sequence were compared to the TIGR rice pseudomolecules. One-hundred sixty one maize sequences that correspond to rice genes were found dispersed throughout the genome, suggesting that large-scale synteny has dissipated since species divergence. In contrast, mico-colinearity is still intact, shown by groups of multiple genes that have retained relative distribution and orientation in both species. Additionally, several single copy maize genes from the rf1 region are found in multiple positions on the rice genome, restricted to either single chromosomes or particular areas within chromosomes. This sequence contig facilitates a candidate gene approach towards identification of the rf1 family while also providing a basis for comparison of functionally related regions in cereals. Research funded by USDA-NRI 2002-35301-12064.