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Interorganellar DNA transfer in wheat: dynamics and phylogenetic origin.

Tsunewaki K - Proc. Jpn. Acad., Ser. B, Phys. Biol. Sci. (2011)

Bottom Line: Six other xenologs showed recurrent transfer from the ct to mt genomes in more than one taxon.The two remaining xenologs were uninformative on the evolutionary timing of their transfer.The wheat mt nad9 gene was found to be chimeric, consisting of the cereal nad9 gene and its 291 bp 5'-flanking region that included a 58 bp xenolog of the ct-ndhC origin.

View Article: PubMed Central - PubMed

Affiliation: Kyoto University, Japan. kkcqn857@yahoo.co.jp

ABSTRACT
A homology search of wheat chloroplast (ct) and mitochondrial (mt) genomes identified 54 ctDNA segments that have homology with 66 mtDNA segments. The mtDNA segments were classified according to their origin: orthologs (prokaryotic origin), xenologs (interorganellar DNA transfer origin) and paralogs (intraorganellar DNA amplification origin). The 66 mtDNA sequences with homology to ctDNA segments included 14 paralogs, 18 orthologs and 34 xenologs. Analysis of the xenologs indicated that the DNA transfer occurred unidirectionally from the ct genome to the mt genome. The evolutionary timing of each interorganellar DNA transfer that generated a xenolog was estimated. This analysis showed that 2 xenologs originated early in green plant evolution, 4 in angiosperm evolution, 3 in monocotyledon evolution, 9 during cereal diversification and 8 in the evolution of wheat. Six other xenologs showed recurrent transfer from the ct to mt genomes in more than one taxon. The two remaining xenologs were uninformative on the evolutionary timing of their transfer. The wheat mt nad9 gene was found to be chimeric, consisting of the cereal nad9 gene and its 291 bp 5'-flanking region that included a 58 bp xenolog of the ct-ndhC origin.

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Map and sequence relationships between segments no. 3 and 20 in the wheat mt and ct genomes. The no. 3 mtDNA segment is a transferant of the no. 3 ctDNA segment that carries the ct-trnC gene, whereas the no. 20 ctDNA segment is not a transferant of the no. 3 mtDNA segment but is the 47 bp central portion of ct-trnF gene. The mt-trnC is the ct genome-derived trnC gene.14) The 46 bp nucleotide sequence of the no. 3 ctDNA segment, the corresponding 46 bp sequence of the nos. 3 and 20 mtDNA segments, the 47 bp nucleotide sequences of the no. 20 ctDNA segment, and the 47 bp central portion of ct-trnF gene are shown in the inserted box.
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fig04: Map and sequence relationships between segments no. 3 and 20 in the wheat mt and ct genomes. The no. 3 mtDNA segment is a transferant of the no. 3 ctDNA segment that carries the ct-trnC gene, whereas the no. 20 ctDNA segment is not a transferant of the no. 3 mtDNA segment but is the 47 bp central portion of ct-trnF gene. The mt-trnC is the ct genome-derived trnC gene.14) The 46 bp nucleotide sequence of the no. 3 ctDNA segment, the corresponding 46 bp sequence of the nos. 3 and 20 mtDNA segments, the 47 bp nucleotide sequences of the no. 20 ctDNA segment, and the 47 bp central portion of ct-trnF gene are shown in the inserted box.

Mentions: In contrast, a dual transfer of an mtDNA segment from a single mt genomic region (mt-coordinates 97,417–97,861) to two separate sites in the ct genome was suspected in only one case (Fig. 4). The no. 20 mtDNA segment is a part of the no. 3 mtDNA segment, as was clear from their mt-coordinates (97,436–97,481 and 97,417–97,861, respectively), whereas their ctDNA homologues were found in two different sites of the ct genome (ct-coordinates 18,282–18,754 and 48,073–48,119; Fig. 4).


Interorganellar DNA transfer in wheat: dynamics and phylogenetic origin.

Tsunewaki K - Proc. Jpn. Acad., Ser. B, Phys. Biol. Sci. (2011)

Map and sequence relationships between segments no. 3 and 20 in the wheat mt and ct genomes. The no. 3 mtDNA segment is a transferant of the no. 3 ctDNA segment that carries the ct-trnC gene, whereas the no. 20 ctDNA segment is not a transferant of the no. 3 mtDNA segment but is the 47 bp central portion of ct-trnF gene. The mt-trnC is the ct genome-derived trnC gene.14) The 46 bp nucleotide sequence of the no. 3 ctDNA segment, the corresponding 46 bp sequence of the nos. 3 and 20 mtDNA segments, the 47 bp nucleotide sequences of the no. 20 ctDNA segment, and the 47 bp central portion of ct-trnF gene are shown in the inserted box.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3313693&req=5

fig04: Map and sequence relationships between segments no. 3 and 20 in the wheat mt and ct genomes. The no. 3 mtDNA segment is a transferant of the no. 3 ctDNA segment that carries the ct-trnC gene, whereas the no. 20 ctDNA segment is not a transferant of the no. 3 mtDNA segment but is the 47 bp central portion of ct-trnF gene. The mt-trnC is the ct genome-derived trnC gene.14) The 46 bp nucleotide sequence of the no. 3 ctDNA segment, the corresponding 46 bp sequence of the nos. 3 and 20 mtDNA segments, the 47 bp nucleotide sequences of the no. 20 ctDNA segment, and the 47 bp central portion of ct-trnF gene are shown in the inserted box.
Mentions: In contrast, a dual transfer of an mtDNA segment from a single mt genomic region (mt-coordinates 97,417–97,861) to two separate sites in the ct genome was suspected in only one case (Fig. 4). The no. 20 mtDNA segment is a part of the no. 3 mtDNA segment, as was clear from their mt-coordinates (97,436–97,481 and 97,417–97,861, respectively), whereas their ctDNA homologues were found in two different sites of the ct genome (ct-coordinates 18,282–18,754 and 48,073–48,119; Fig. 4).

Bottom Line: Six other xenologs showed recurrent transfer from the ct to mt genomes in more than one taxon.The two remaining xenologs were uninformative on the evolutionary timing of their transfer.The wheat mt nad9 gene was found to be chimeric, consisting of the cereal nad9 gene and its 291 bp 5'-flanking region that included a 58 bp xenolog of the ct-ndhC origin.

View Article: PubMed Central - PubMed

Affiliation: Kyoto University, Japan. kkcqn857@yahoo.co.jp

ABSTRACT
A homology search of wheat chloroplast (ct) and mitochondrial (mt) genomes identified 54 ctDNA segments that have homology with 66 mtDNA segments. The mtDNA segments were classified according to their origin: orthologs (prokaryotic origin), xenologs (interorganellar DNA transfer origin) and paralogs (intraorganellar DNA amplification origin). The 66 mtDNA sequences with homology to ctDNA segments included 14 paralogs, 18 orthologs and 34 xenologs. Analysis of the xenologs indicated that the DNA transfer occurred unidirectionally from the ct genome to the mt genome. The evolutionary timing of each interorganellar DNA transfer that generated a xenolog was estimated. This analysis showed that 2 xenologs originated early in green plant evolution, 4 in angiosperm evolution, 3 in monocotyledon evolution, 9 during cereal diversification and 8 in the evolution of wheat. Six other xenologs showed recurrent transfer from the ct to mt genomes in more than one taxon. The two remaining xenologs were uninformative on the evolutionary timing of their transfer. The wheat mt nad9 gene was found to be chimeric, consisting of the cereal nad9 gene and its 291 bp 5'-flanking region that included a 58 bp xenolog of the ct-ndhC origin.

Show MeSH