A common sequence difference between cytoplasmic male sterile lines and their maintainer lines existing in rice (Oryza sativa L.) chloroplast tRNA-Leu gene region

Abstract

DNA polymorphism between a wild-abortivecytoplasmic male sterile line Zhenshan97Aand its maintainer line Zhenshan97B wasanalyzed using AFLP technique. Among the1953 amplified bands, a stable polymorphicfragment was identified, and designated asA1 in Zhenshan97A and B1 inZhenshan97B. Sequence and homology analysisshowed that A1 contained a more tandemrepeat of 6 base pairs (AGAAAA) thanB1 and the repeat was located 7-baseupstream to the transcription start site ofthe rice chloroplast tRNA-Leu gene.According to this difference, a pair ofspecific primers was designed toinvestigate the distribution of thedifference in 5 pairs of CMS and theircorresponding maintainer lines by PCR. Itwas demonstrated that a single band couldbe amplified from all the 5 CMS lines whilenone from the maintainer lines. Sequencesanalysis of the differential regions of the5 pairs of CMS and maintainer lines showedthat all the 5 CMS lines contained this 6bprepeat, whereas the correspondingmaintainer lines did not. It was proposed thatthis differential fragment was likelyassociated with cytoplasmic malesterility.