A fragment of chloroplast DNA was transferred horizontally, probably from non-eudicots, to mitochondrial genome of Phaseolus

Journal or Publishing Institution: Plant Molecular Biology

Study: http://www.ncbi.nlm.nih.gov/pubmed/15803417

Author(s): Woloszynska, M., Bocer, T., Mackiewicz, P. and Janska, H.

Article Type: Peer Reviewed Study

Abstract: The mitochondrial genomes of some Phaseolus species contain a fragment of chloroplast trnA gene intron, named pvs-trnA for its location within the Phaseolus vulgaris sterility sequence (pvs). The purpose of this study was to determine the type of transfer (intracellular or horizontal) that gave rise to pvs-trnA. Using a PCR approach we could not find the respective portion of the trnA gene as a part of pvs outside the Phaseolus genus. However, a BLAST search revealed longer fragments of trnA present in the mitochondrial genomes of some Citrus species, Helianthus annuus and Zea mays. Basing on the identity or near-identity between these mitochondrial sequences and their chloroplast counterparts we concluded that they had relocated from chloroplasts to mitochondria via recent, independent, intracellular DNA transfers. In contrast, pvs-trnA displayed a relatively higher sequence divergence when compared with its chloroplast counterpart from Phaseolus vulgaris. Alignment of pvs-trnA with corresponding trnA fragments from 35 plant species as well as phylogenetic analysis revealed that pvs-trnA grouped with non-eudicot sequences and was well separated from all Fabales sequences. In conclusion, we propose that pvs-trnA arose via horizontal transfer of a trnA intron fragment from chloroplast of a non-eudicot plant to Phaseolus mitochondria. This is the first example of horizontal transfer of a chloroplast sequence to the mitochondrial genome in higher plants.

Keywords: Chloroplast trnA Gene, Plants, Introgression, Phaseolus Vulgaris, Phaseolus Lunatus, Chloroplast DNA, Mitochondrial DNA, Phaseolus; Sequence Alignment, Molecular Sequence Data, Phaseolus, Horizontal Gene Transfer, pvs-trnA sequence, Phaseolus Glabellus, Nucleotide Sequences; Plant Mitochondrial DNA, Intracelluar Gene Transfer; Base Sequence, Plant DNA, Phylogeny, Plant Proteins, Ala Transfer RNA, Nucleic Acid Sequence Homology

Citation: Woloszynska, M., Bocer, T., Mackiewicz, P. and Janska, H., 2004. A fragment of chloroplast DNA was transferred horizontally, probably from non-eudicots, to mitochondrial genome of Phaseolus. Plant Molecular Biology, 56(5), pp.811-820.