Plastid RNA polymerases: orchestration of enzymes with different evolutionary origins controls chloroplast biogenesis during the plant life cycle.
Chloroplasts are the sunlight-collecting organelles of photosynthetic eukaryotes that energetically drive the biosphere of our planet. They are the base for all major food webs by providing essential photosynthates to all heterotrophic organisms including humans. Recent research has focused largely on an understanding of the function of these organelles, but knowledge about the biogenesis of chloroplasts is rather limited. It is known that chloroplasts develop from undifferentiated precursor plastids, the proplastids, in meristematic cells. This review focuses on the activation and action of plastid RNA polymerases, which play a key role in the development of new chloroplasts from proplastids. Evolutionarily, plastids emerged from the endosymbiosis of a cyanobacterium-like ancestor into a heterotrophic eukaryote. As an evolutionary remnant of this process, they possess their own genome, which is expressed by two types of plastid RNA polymerase, phage-type and prokaryotic-type RNA polymerase. The protein subunits of these polymerases are encoded in both the nuclear and plastid genomes. Their activation and action therefore require a highly sophisticated regulation that controls and coordinates the expression of the components encoded in the plastid and nucleus. Stoichiometric expression and correct assembly of RNA polymerase complexes is achieved by a combination of developmental and environmentally induced programmes. This review highlights the current knowledge about the functional coordination between the different types of plastid RNA polymerases and provides working models of their sequential expression and function for future investigations.
Université Grenoble-Alpes, F-38000 Grenoble, France CNRS, UMR5168, F-38054 Grenoble, France CEA, iRTSV, Laboratoire de Physiologie Cellulaire & Végétale, F-38054 Grenoble, France INRA, USC1359, F-38054 Grenoble, France Thomas.Pfannschmidt@ujf-grenoble.fr.
Thomas
T
Pfannschmidt
Université Grenoble-Alpes, F-38000 Grenoble, France CNRS, UMR5168, F-38054 Grenoble, France CEA, iRTSV, Laboratoire de Physiologie Cellulaire & Végétale, F-38054 Grenoble, France INRA, USC1359, F-38054 Grenoble, France.
Robert
R
Blanvillain
Université Grenoble-Alpes, F-38000 Grenoble, France CNRS, UMR5168, F-38054 Grenoble, France CEA, iRTSV, Laboratoire de Physiologie Cellulaire & Végétale, F-38054 Grenoble, France INRA, USC1359, F-38054 Grenoble, France.
Livia
L
Merendino
Université Grenoble-Alpes, F-38000 Grenoble, France CNRS, UMR5168, F-38054 Grenoble, France CEA, iRTSV, Laboratoire de Physiologie Cellulaire & Végétale, F-38054 Grenoble, France INRA, USC1359, F-38054 Grenoble, France.
Florence
F
Courtois
Université Grenoble-Alpes, F-38000 Grenoble, France CNRS, UMR5168, F-38054 Grenoble, France CEA, iRTSV, Laboratoire de Physiologie Cellulaire & Végétale, F-38054 Grenoble, France INRA, USC1359, F-38054 Grenoble, France.
Fabien
F
Chevalier
Université Grenoble-Alpes, F-38000 Grenoble, France CNRS, UMR5168, F-38054 Grenoble, France CEA, iRTSV, Laboratoire de Physiologie Cellulaire & Végétale, F-38054 Grenoble, France INRA, USC1359, F-38054 Grenoble, France.
Monique
M
Liebers
Université Grenoble-Alpes, F-38000 Grenoble, France CNRS, UMR5168, F-38054 Grenoble, France CEA, iRTSV, Laboratoire de Physiologie Cellulaire & Végétale, F-38054 Grenoble, France INRA, USC1359, F-38054 Grenoble, France.
Björn
B
Grübler
Université Grenoble-Alpes, F-38000 Grenoble, France CNRS, UMR5168, F-38054 Grenoble, France CEA, iRTSV, Laboratoire de Physiologie Cellulaire & Végétale, F-38054 Grenoble, France INRA, USC1359, F-38054 Grenoble, France.
Elisabeth
E
Hommel
Université Grenoble-Alpes, F-38000 Grenoble, France CNRS, UMR5168, F-38054 Grenoble, France CEA, iRTSV, Laboratoire de Physiologie Cellulaire & Végétale, F-38054 Grenoble, France INRA, USC1359, F-38054 Grenoble, France.
Silva
S
Lerbs-Mache
D005075:Biological Evolution; D002736:Chloroplasts / Q000378:metabolism*; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D004789:Enzyme Activation; D008018:Life Cycle Stages; D010944:Plants / Q000378:metabolism*; D018749:RNA, Plant / Q000378:metabolism
D018749:RNA, Plant; D012321:DNA-Directed RNA Polymerases
Chloroplast biogenesis; developmental regulation; gene expression; nucleo–plastid interaction; plants; plastid RNA polymerases.