title: Organellar gene transcription and early seedling development are affected in the rpoT;2 mutant of Arabidopsis.
abstract: An Arabidopsis mutant that exhibited reduced root length was isolated from a population of activation-tagged T-DNA insertion lines in a screen for aberrant root growth. This mutant also exhibited reduced hypocotyl length as well as a delay in greening and altered leaf shape. Molecular genetic analysis of the mutant indicated a single T-DNA insertion in the gene RpoT;2 encoding a homolog of the phage-type RNA polymerase (RNAP), that is targeted to both mitochondria and plastids. A second T-DNA-tagged allele also showed a similar phenotype. The mutation in RpoT;2 affected the light-induced accumulation of several plastid mRNAs and proteins and resulted in a lower photosynthetic efficiency. In contrast to the alterations in the plastid gene expression, no major effect of the rpoT;2 mutation on the accumulation of examined mitochondrial gene transcripts and proteins was observed. The rpoT;2 mutant exhibited tissue-specific alterations in the transcript levels of two other organelle-directed nuclear-encoded RNAPs, RpoT;1 and RpoT;3. This suggests the existence of cross-talk between the regulatory pathways of the three RNAPs through organelle to nucleus communication. These data provide an important information on a role of RpoT;2 in plastid gene expression and early plant development.
authors.affiliation: Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 901 83 Umeå, Sweden.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Baba
authors.forename: Julien
authors.initials: J
authors.lastname: Schmidt
authors.forename: Ana
authors.initials: A
authors.lastname: Espinosa-Ruiz
authors.forename: Arsenio
authors.initials: A
authors.lastname: Villarejo
authors.forename: Takashi
authors.initials: T
authors.lastname: Shiina
authors.forename: Per
authors.initials: P
authors.lastname: Gardeström
authors.forename: Aniruddha P
authors.initials: AP
authors.lastname: Sane
authors.forename: Rishikesh P
authors.initials: RP
authors.lastname: Bhalerao
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000378:metabolism; D001483:Base Sequence; D004251:DNA Transposable Elements / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D008928:Mitochondria / Q000235:genetics; D016254:Mutagenesis, Insertional; D009154:Mutation; D015388:Organelles / Q000235:genetics; D045332:Photosystem II Protein Complex / Q000378:metabolism; D018087:Plastids / Q000235:genetics; D036226:Seedlings / Q000254:growth & development
chemical_list: D029681:Arabidopsis Proteins; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D018744:DNA, Plant; D045332:Photosystem II Protein Complex; C036483:T-DNA; D012321:DNA-Directed RNA Polymerases