SALT LAKE CITY, UTAH
University of Utah

ST. LOUIS, MISSOURI
Washington University

COLUMBIA, MISSOURI
University of Missouri

Sequence comparisons of six mitochondrial genomes from maize and teosinte

--Fauron, C, Minx, P, Gibson, M, Allen, J, Clifton, SW, Newton, K

Plant mitochondrial genomes are unusual in their diversity of structure and rapidity of change. Previously, only six mitochondrial genomes (mtDNA) had been completely sequenced: the liverwort, Marchantia polymorpha, three dicots, Arabidopsis thaliana, Beta vulgaris, Brassica napus, and a monocot, Oryza sativa. We have sequenced another six monocots within the genus Zea including fertile (NB and NA genotypes) and male sterile (cms-T and cms-C genotypes) maize and two teosintes from section Luxuriantes, Zea luxurians and Zea perennis. In addition, the mtDNA sequences of a related grass, Sorghum bicolor, is complete but still duplications have not been fully defined.

The sequencing of the Zea mays mitochondrial genomes from NB (GenBank Accession AY506529), NA and cms-C generated circular maps of 569,630, 701,046 and 739,719 base pairs respectively; Zea luxurians and Zea perennis mtDNAs also generate circular maps which are 539,347 and 570,353 bp long respectively. Sequencing of cms-T is 95% complete. Sequence comparisons reveal major rearrangements, large duplications, various foreign DNA insertions, but few differences in gene content.

This work has been supported by National Science Foundation grant DBI-0110168.

The outer circle shows genes of Zea mays mays NB mtDNA and the outer ring contains NB mtDNA large repeats (500bp long and higher).

Going towards the center of the circle the rings respectively represent NA mtDNA, cms-C mtDNA, cms-T mtDNA, Zea luxurians mtDNA, Zea perennis mtDNA, and Sorghum bicolor mtDNA. The gray scale indicates percent of similarity: from black (100% similarity) to white (below 60% similarity) identified from a BLASTN search (WashU BLAST 2.0) comparing each genome with the maize NB genome.

The innermost ring circle shows the positions of chloroplast inserts (medium gray), while the lines extending from the innermost circle indicate positions of unidentified open reading frames (99 amino acids or greater) in the NB genome.

It should not be inferred from this comparison that the genomes are the same size. The various shades in the rings indicate only the percent similarity to the NB genome

Table 1. List of known genes from maize NB mitochondrial genome also located on Figure 1.