The plant mitochondrial genome: dynamics and maintenance.
Plant mitochondria have a complex and peculiar genetic system. They have the largest genomes, as compared to organelles from other eukaryotic organisms. These can expand tremendously in some species, reaching the megabase range. Nevertheless, whichever the size, the gene content remains modest and restricted to a few polypeptides required for the biogenesis of the oxidative phosphorylation chain complexes, ribosomal proteins, transfer RNAs and ribosomal RNAs. The presence of autonomous plasmids of essentially unknown function further enhances the level of complexity. The physical organization of the plant mitochondrial DNA includes a set of sub-genomic forms resulting from homologous recombination between repeats, with a mixture of linear, circular and branched structures. This material is compacted into membrane-bound nucleoids, which are the inheritance units but also the centers of genome maintenance and expression. Recombination appears to be an essential characteristic of plant mitochondrial genetic processes, both in shaping and maintaining the genome. Under nuclear surveillance, recombination is also the basis for the generation of new mitotypes and is involved in the evolution of the mitochondrial DNA. In line with, or as a consequence of its complex physical organization, replication of the plant mitochondrial DNA is likely to occur through multiple mechanisms, potentially involving recombination processes. We give here a synthetic view of these aspects.
Institut de Biologie Moléculaire des Plantes, CNRS and Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg, France. Electronic address: jose.gualberto@ibmp-cnrs.unistra.fr.
José M
JM
Gualberto
Institut de Biologie Moléculaire des Plantes, CNRS and Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg, France. Electronic address: Daria.Mileshina@ibmp-cnrs.unistra.fr.
Daria
D
Mileshina
Institut de Biologie Moléculaire des Plantes, CNRS and Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg, France. Electronic address: clementine.wallet@ibmp-cnrs.unistra.fr.
Clémentine
C
Wallet
Institut de Biologie Moléculaire des Plantes, CNRS and Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg, France. Electronic address: Adnan-Khan.Niazi@ibmp-cnrs.unistra.fr.
Adnan Khan
AK
Niazi
Institut de Biologie Moléculaire des Plantes, CNRS and Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg, France. Electronic address: lotfif@unistra.fr.
Frédérique
F
Weber-Lotfi
Institut de Biologie Moléculaire des Plantes, CNRS and Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg, France. Electronic address: andre.dietrich@ibmp-cnrs.unistra.fr.
André
A
Dietrich
D004260:DNA Repair; D004261:DNA Replication; D004272:DNA, Mitochondrial / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D059646:Genome Size; D054629:Genome, Mitochondrial; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D010944:Plants / Q000235:genetics* / Q000378:metabolism; D010957:Plasmids / Q000737:chemistry / Q000378:metabolism; D014176:Protein Biosynthesis; D012343:RNA, Transfer / Q000737:chemistry / Q000378:metabolism; D011995:Recombination, Genetic
D004272:DNA, Mitochondrial; D024101:Mitochondrial Proteins; D010940:Plant Proteins; D012343:RNA, Transfer
Mitochondria; Recombination; Repair; Replication; mtDNA