Mitochondrial-specific RAPD analysis in the Lycopersicon CMS system
1Gianniny, Christine, 2Stoeva-Popova, Pravda, and 1Dimaculangan, Dwight
1Department of Biology, Winthrop University, Rock Hill, SC 29733,
E-mail: dimaculangad@winthrop.edu
2AgroBio Institute, Blvd. Dragan Tsankov No 8, Sofia 1164, Bulgaria,
E-mail: pravda_stoeva@abi.bg
Cytoplasmic male sterility (CMS) plant systems are desirable in agriculturally important
species because they allow for efficient production of hybrid seeds without the need for flower hand
emasculation. In all systems characterized thus far, CMS results from incompatibility between
nuclear and cytoplasmic cellular components emerging as a consequence of
interspecific/intraspecific hybridization or mutations. In CMS systems, pollen development is
affected by as yet unknown mechanisms due to recombination events in the mitochondrial genome.
In spite of species specific differences, the general mechanisms common to all of the CMS systems
are the altered expression of mitochondrial genes and/or novel gene products that lead to pollen
sterility, and the regulation of nuclear genes that mask the mitochondrial CMS-related changes to
restore fertility (Hanson, 1991; Kempken and Pring, 1999).
The Lycopersicon CMS system had been produced in BC3-P2 (L. peruvianum x L. pennellii)
(Vulkova-Achkova, 1980). The CMS phenotype is maintained over many generations through
pollination with L. pennellii. The restoration of fertility takes place when nuclear genes from the
cultivated tomato are incorporated, as observed in complex hybrids F2-F3 [CMS-pennellii x (F1 L.
esculentum x L. pennellii)] (Petrova et al., 1998; 1999 and our unpublished data). We hypothesize
that as a result of the interaction between the cytoplasm of L. peruvianum and the nuclear genome
of L. pennellii, similar phenomena, involving the recombination of the mitochondrial genome
structure and the altered expression of mitochondrial RNA, as well as the regulation of nuclear
restoration genes, are responsible for sterility and fertility restoration in the developed Lycopersicon
CMS system.
To characterize the mtDNA rearrangements that occurred in the CMS plants we developed a
mitochondrial-specific randomly amplified polymorphic DNA analysis (mitochondrial-specific RAPD)
that is free of the nuclear DNA derived artifacts (Gianniny et. al. 2004).
With this technique we can generate unique RAPD banding patterns among several
Lycoperiscon species that are highly reproducible throughout multiple preparations from the same
species (Gianniny et. al. 2004). Using different primers, this method generates unique banding
patterns in CMS-pennellii when compared to the original donor of the mitochondrial genome L.
peruvianum (Figure 1 A, B and C). The CMS-pennellii specific bands confirm that as a result of
nuclear cytoplasm interactions mitochondrial DNA rearrangements had taken place. Their further
characterization will allow identification of specific CMS-related structural changes to the
mitochondrial genome.
The developed mtRAPD technique is suitable for general genetic comparisons among
related plant species as well as for analysis of mitochondrial genome rearrangements associated
with CMS.
Acknowledgements
This work was supported in part by seed grant no. 2001-01500 for the U.S. Department of
Agriculture (USDA).
Literature Cited
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