Fertility restoration by Ifr1 in rice with BT-type cytoplasmic male sterility is associated with a reduced level, but not processing, of atp6-orf79 co-transcribed RNA

• Published in: Plant cell reports Vol. 29; no. 4; pp. 359 - 369
• Main Authors: Ohta, Haruka, Ogino, Atsushi, Kasai, Megumi, Sano, Yoshio, Kanazawa, Akira
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.04.2010; Springer; Springer Nature B.V
• Subjects: Biological and medical sciences; Biomedical and Life Sciences; Biotechnology; Cell Biology; Comparative Genomic Hybridization; Fertility; Fundamental and applied biological sciences. Psychology; Gene Expression Profiling; Gene Expression Regulation, Plant; Genes, Plant; Life Sciences; Male sterility; Open Reading Frames; Original Paper; Oryza - genetics; Oryza - metabolism; Oryza - physiology; Oryza sativa; Plant Biochemistry; Plant Infertility - genetics; Plant Proteins - genetics; Plant Proteins - metabolism; Plant Sciences; Pollen - genetics; Pollen - growth & development; RNA Stability; RNA, Plant - genetics; Sequence Analysis, DNA; Transcription, Genetic; Mitochondrial DNA; Fertility restorer; RNA processing; Cytoplasmic male sterility; Monocotyledones; Vegetals; RNA; Bacillus thuringiensis; Restoration of fertility; Bacillaceae; Oryza sativa; Bacillales; Gramineae; Angiospermae; Bacteria; Spermatophyta; Transgenic plant
• ISSN: 0721-7714; 1432-203X
• DOI: 10.1007/s00299-010-0827-7

BT-type cytoplasmic male sterility (CMS) in rice is associated with accumulation of unprocessed dicistronic RNA containing a duplicated atp6 (B- atp6 ) and an unusual open reading frame, orf79 , encoding a cytotoxic peptide in mitochondria. The male-sterile state of BT-type CMS is stably maintained by backcrossing the plants with line Taichung 65 (T65) that has no restorer gene and is completely suppressed by the presence of the Rf1 gene through the processing of B- atp6 - orf79 RNA. A variant of the T65 line, T65(T), has a weak restoration function conferred by the Ifr1 gene, which is genetically independent of the Rf1 gene. However, not much is known about the mechanism(s). In a study to examine whether the mechanism involved in fertility restoration by Ifr1 is analogous to restoration mediated by Rf1 , the transcript profile of B- atp6 - orf79 in male-sterile plants was compared with that in fertility restored plants obtained by crossing male-sterile plants with T65(T). The cellular level of unprocessed B- atp6 - orf79 RNA was reduced in the restored plants, but no change in processing efficiency or the quantity of B- atp6 - orf79 DNA was detected. These results suggest that Ifr1 restores fertility through reducing either the transcription rate of B- atp6 - orf79 or the stability of its primary transcripts, a mechanism distinct from that involved in fertility restoration of BT-type CMS by Rf1 .