Mitochondrial type-I prohibitins of Arabidopsis thaliana are required for supporting proficient meristem development.
The Arabidopsis thaliana genome expresses five evolutionarily conserved prohibitin (PHB) genes that are divided into type-I (AtPHB3 and AtPHB4) and type-II (AtPHB1, AtPHB2 and AtPHB6) classes, based on their phylogenetic relationships with yeast PHB1 and PHB2, respectively. Yeast and animal PHBs are reported to have diverse roles in the cell cycle, mitochondrial electron transport, aging and apoptosis. All transcribed Arabidopsis PHB genes are primarily expressed in both shoot and root proliferative tissues, where they are present in mitochondrial multimeric complexes. Loss of function of the type-I AtPHB4 had no phenotypic effects, while loss of function of the homologous AtPHB3 caused mitochondrial swelling, decreased meristematic cell production, increased cell division time and reduced cell expansion rates, leading to severe growth retardation. Double knockout atphb3 atphb4 plants were not viable, but transgenic lines overexpressing AtPHB3 or AtPHB4 showed leaf shape aberrations and an increased shoot branching phenotype. Genome-wide microarray analysis revealed that both knockout and overexpression perturbations of AtPHB3 and AtPHB4 provoked an altered abundance of mitochondrial and stress-related transcripts. We propose that plant type-I PHBs take part in protein complexes that are necessary for proficient mitochondrial function or biogenesis, thereby supporting cell division and differentiation in apical tissues.
Van Aken
Olivier
O
Department of Plant Systems Biology, Flanders Institute for Biotechnology, 9052 Gent, Belgium.
Pecenková
Tamara
T
van de Cotte
Brigitte
B
De Rycke
Riet
R
Eeckhout
Dominique
D
Fromm
Hillel
H
De Jaeger
Geert
G
Witters
Erwin
E
Beemster
Gerrit T S
GT
Inzé
Dirk
D
Van Breusegem
Frank
F
D017360:Arabidopsis / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002455:Cell Division; D016000:Cluster Analysis; D018519:Meristem / Q000254:growth & development* / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D010641:Phenotype; D010802:Phylogeny; D000091402:Prohibitins; D021381:Protein Transport; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
D029681:Arabidopsis Proteins; C000717327:AtPHB3 protein, Arabidopsis; D024101:Mitochondrial Proteins; D000091402:Prohibitins; D012097:Repressor Proteins