Columbia, Missouri
University of Missouri
St. Louis, Missouri
Washington University
Salt Lake City, Utah
University of Utah
Sequence, expression and evolution of mitochondrial genomes in the genus
Zea
--Newton, K, Clifton, SW, Fauron, C
Plant mitochondrial genomes are unusual in their diversity of structure
and rapidity of change. Although most of the known coding regions are very
conserved, large intergenic regions show no sequence similarities. These
"non-coding" regions have important roles in the rapid structural evolution
seen for plant mitochondrial genomes, and
they can become functional as components of chimeric genes that have been
described as being responsible for several cases of cytoplasmic male sterility
(CMS). In order to understand how non-coding regions of mitochondrial genomes
contribute to their structural and functional diversity, it is necessary
to examine closely related species. To address these issues, five mitochondrial
genomes within the genus Zea, including fertile and CMS mtDNAs of
maize, Zea parviglumis (the probable progenitor of maize), Zea
perennis (from the most distant section of the teosintes), will
be sequenced and compared to the mtDNA sequences of a related grass, Tripsacumdactyloides
and a more distantly related plant,
Sorghum bicolor. A direct sequencing approach will be complemented
with the efficient mapping of several Zea mitochondrial genotypes.
The regions of a fertile maize mitochondrial genome that are functional
will be determined by expression analyses using mitochondrial RNAs from
different tissues and stages of development. Previous data indicated that
some mitochondrial genes are expressed preferentially during specific stages
of development. The extent of this diversity of expression will be examined.
This NSF-funded genomeproject
willcontribute to an understanding of the content, organization
and expression of grass mitochondrial genomes.
Please Note: Notes submitted to the Maize Genetics Cooperation Newsletter may be cited only with consent of the authors.
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