title: Transgenic expression of an unedited mitochondrial orfB gene product from wild abortive (WA) cytoplasm of rice (Oryza sativa L.) generates male sterility in fertile rice lines.
abstract: Over-expression of the unedited mitochondrial orfB gene product generates male sterility in fertile indica rice lines in a dose-dependent manner. Cytoplasmic male sterility (CMS) and nuclear-controlled fertility restoration are widespread developmental features in plant reproductive systems. In self-pollinated crop plants, these processes often provide useful tools to exploit hybrid vigour. The wild abortive CMS has been employed in the majority of the "three-line" hybrid rice production since 1970s. In the present study, we provide experimental evidence for a positive functional relationship between the 1.1-kb unedited orfB gene transcript, and its translated product in the mitochondria with male sterility. The generation of the 1.1-kb unedited orfB gene transcripts increased during flowering, resulting in low ATP synthase activity in sterile plants. Following insertion of the unedited orfB gene into the genome of male-fertile plants, the plants became male sterile in a dose-dependent manner with concomitant reduction of ATPase activity of F1F0-ATP synthase (complex V). Fertility of the transgenic lines and normal activity of ATP synthase were restored by down-regulation of the unedited orfB gene expression through RNAi-mediated silencing. The genetic elements deciphered in this study could further be tested for their use in hybrid rice development.
authors.affiliation: Advanced Laboratory for Plant Genetic Engineering, Indian Institute of Technology, Kharagpur, 721302, India.
authors.forename: Anirban
authors.initials: A
authors.lastname: Chakraborty
authors.forename: Joy
authors.initials: J
authors.lastname: Mitra
authors.forename: Jagannath
authors.initials: J
authors.lastname: Bhattacharyya
authors.forename: Subrata
authors.initials: S
authors.lastname: Pradhan
authors.forename: Narattam
authors.initials: N
authors.lastname: Sikdar
authors.forename: Srirupa
authors.initials: S
authors.lastname: Das
authors.forename: Saikat
authors.initials: S
authors.lastname: Chakraborty
authors.forename: Sachin
authors.initials: S
authors.lastname: Kumar
authors.forename: Suman
authors.initials: S
authors.lastname: Lakhanpaul
authors.forename: Soumitra K
authors.initials: SK
authors.lastname: Sen
mesh_terms: D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000235:genetics*; D015536:Down-Regulation; D004579:Electron Transport; D005298:Fertility / Q000235:genetics; D035264:Flowers / Q000235:genetics / Q000254:growth & development; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000235:genetics* / Q000378:metabolism; D025261:Mitochondrial Proton-Translocating ATPases / Q000378:metabolism; D012275:Oryza / Q000235:genetics* / Q000502:physiology*; D051479:Plant Infertility / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D017393:RNA Editing; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D036226:Seedlings / Q000235:genetics; D013997:Time Factors; D014170:Transformation, Genetic
chemical_list: D024101:Mitochondrial Proteins; D010940:Plant Proteins; D012333:RNA, Messenger; C474451:F1F0-ATP synthase; D025261:Mitochondrial Proton-Translocating ATPases