title: Homology-based cloning and expression analysis of Rf genes encoding PPR-containing proteins in tobacco.
abstract: As a model plant, mechanisms of the cytoplasmic male sterility/restoration of fertility (CMS/Rf) system in tobacco are seldom studied. Using Rf gene sequences from other Solanaceae plants and the draft genome of Nicotiana benthamiana, degenerate primers were designed to amplify the cDNA pool of N. tomentosiformis. In total, six possible Rf sequences were identified, two of which contained base-deletion mutations. The other four were intact open reading frames, of which NtomPPR5 harbored a 3-pentatricopeptide repeat (PPR) motif deletion. Structure analysis revealed that they all encoded a PPR-containing protein with putative mitochondrial targeting signals at their N-terminus, and they all belong to the P subfamily. Phylogenetic analysis showed that all of the Rf-coding PPRs clustered together, and recent duplication events might have occurred in tobacco after the divergence of the species. Quantitative reverse transcription polymerase chain reaction analysis demonstrated that the NtomRfs were expressed in all tissues of N. tomentosiformis and (CMS) K326, although the expression levels varied with gene, organ, and developmental stage. Furthermore, the expression levels of Rf sequences in K326 were lower than those in CMS K326. The molecular basis of the CMS/Rf system in tobacco requires further investigation.
authors.affiliation: Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, China.
authors.forename: A M
authors.initials: AM
authors.lastname: Ding
authors.affiliation: Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, China.
authors.forename: F X
authors.initials: FX
authors.lastname: Li
authors.affiliation: Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, China.
authors.forename: Y Q
authors.initials: YQ
authors.lastname: Chen
authors.affiliation: Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, China.
authors.forename: P
authors.initials: P
authors.lastname: Zong
authors.affiliation: Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, China.
authors.forename: X
authors.initials: X
authors.lastname: Qu
authors.affiliation: Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, China.
authors.forename: D P
authors.initials: DP
authors.lastname: Gong
authors.affiliation: Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, China.
authors.forename: G S
authors.initials: GS
authors.lastname: Liu
authors.affiliation: Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, China yhsun@163.com.
authors.forename: Y H
authors.initials: YH
authors.lastname: Sun
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D016384:Consensus Sequence; D015870:Gene Expression; D008969:Molecular Sequence Data; D005810:Multigene Family; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics*; D056510:Position-Specific Scoring Matrices; D054730:Protein Interaction Domains and Motifs / Q000235:genetics*; D014026:Nicotiana / Q000145:classification / Q000235:genetics*
chemical_list: D010940:Plant Proteins