It is well accepted that S type of cytoplasmic male sterility (CMS) in maize (Zea mays L.) isassociated with R region in mitochondrial genome. R region includes two open reading frames——orf355and orf77and it is spec...It is well accepted that S type of cytoplasmic male sterility (CMS) in maize (Zea mays L.) isassociated with R region in mitochondrial genome. R region includes two open reading frames——orf355and orf77and it is speculated that orf77is an important candidate gene of CMS. RT-PCR showed that bothDNA strands of R region are transcribed. Nuclear background or developing stages of plant do not influencethe transcription of R region in the strand which also acts as template strand of cox Ⅰ/coxⅡ locating justupstream of R region, but they do influence the transcription of R region in the other strand (templatestrand of orf355-orf77). In tassel with nuclear background of rf3rf3, transcription of the template strand oforf355-orf77 is different from that in etiolated shoots with nuclear background of Rf3- or rf3rf3and tasselwith nuclear background of Rf3-. Compared to the same other three, it is truncated at about 238 base fromthe 5' end of R region. Rabbit antiserum against putative ORF77 expressed in Escherichia coliwas preparedbut Western blot did not detect ORF77 in plant materials. It seems that double-strand transcription of Rregion inhibits the translation of orf77and the transcribing mode of R region may be associated with malesterility.展开更多
文摘It is well accepted that S type of cytoplasmic male sterility (CMS) in maize (Zea mays L.) isassociated with R region in mitochondrial genome. R region includes two open reading frames——orf355and orf77and it is speculated that orf77is an important candidate gene of CMS. RT-PCR showed that bothDNA strands of R region are transcribed. Nuclear background or developing stages of plant do not influencethe transcription of R region in the strand which also acts as template strand of cox Ⅰ/coxⅡ locating justupstream of R region, but they do influence the transcription of R region in the other strand (templatestrand of orf355-orf77). In tassel with nuclear background of rf3rf3, transcription of the template strand oforf355-orf77 is different from that in etiolated shoots with nuclear background of Rf3- or rf3rf3and tasselwith nuclear background of Rf3-. Compared to the same other three, it is truncated at about 238 base fromthe 5' end of R region. Rabbit antiserum against putative ORF77 expressed in Escherichia coliwas preparedbut Western blot did not detect ORF77 in plant materials. It seems that double-strand transcription of Rregion inhibits the translation of orf77and the transcribing mode of R region may be associated with malesterility.
