Mutations in the Arabidopsis nuclear-encoded mitochondrial phage-type RNA polymerase gene RPOTm led to defects in pollen tube growth, female gametogenesis and embryogenesis.
The mitochondrial genes in Arabidopsis thaliana are transcribed by a small family of nuclear-encoded T3/T7 phage-type RNA polymerases (RPOTs). At least two nuclear-encoded RPOTs (RPOTm and RPOTmp) are located in mitochondria in A. thaliana. Their genetic roles are largely unknown. Here we report the characterization of novel mutations in the A. thaliana RPOTm gene. The mutations did not affect pollen formation, but significantly retarded the growth of the rpoTm mutant pollen tubes and had an impact on the fusion of the polar nuclei in the rpoTm mutant embryo sacs. Moreover, development of the rpoTm/- mutant embryo was arrested at the globular stage. The rpoTm rpoTmp double mutation could enhance the rpoTm mutant phenotype. Expression of RPOTmp under control of the RPOTm promoter could not complement the phenotype of the rpoTm mutations. All these data indicate that RPOTm is important for normal pollen tube growth, female gametogenesis and embryo development, and has distinct genetic and molecular roles in plant development, which cannot be replaced by RPOTmp.
State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China.
Xiao-Yun
XY
Tan
Xiao-Lei
XL
Liu
Wei
W
Wang
Dong-Jie
DJ
Jia
Li-Qun
LQ
Chen
Xue-Qin
XQ
Zhang
De
D
Ye
D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000502:physiology* / Q000648:ultrastructure; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology*; D015139:Blotting, Southern; D012321:DNA-Directed RNA Polymerases / Q000235:genetics* / Q000502:physiology; D047108:Embryonic Development / Q000235:genetics / Q000502:physiology*; D005718:Gametogenesis / Q000235:genetics / Q000502:physiology*; D046529:Microscopy, Electron, Transmission; D008928:Mitochondria / Q000201:enzymology* / Q000235:genetics / Q000648:ultrastructure; D009154:Mutation; D030821:Plants, Genetically Modified / Q000235:genetics / Q000254:growth & development / Q000502:physiology / Q000648:ultrastructure; D053205:Pollen Tube / Q000235:genetics / Q000254:growth & development*; D016133:Polymerase Chain Reaction; D014764:Viral Proteins / Q000235:genetics* / Q000502:physiology
D029681:Arabidopsis Proteins; D014764:Viral Proteins; C062210:bacteriophage T7 RNA polymerase; D012321:DNA-Directed RNA Polymerases