Abstract: On the base of construction of a new type of cytoplasmic male sterile line Zidao A,we analyzed the editing of transcripts of mitochondrial ATP synthase subunit 9 gene(atp9)from CMS line and its maintainer line.With PCR,RT-PCR,and direct sequencing,complete nucleotide sequences were determined for the mitochondrial atp9 gene and its cDNA from two lines of Purple Rice Type rice(Oryza sativa L.):cytoplasmic male sterile line Ying Xiang A and its maintainer line Ying Xiang B.The atp9 transcript of Ying Xiang A was shown to have no editing sites and the transcript of Ying Xiang B was shown to have 2 editing sites with changes affecting the amino acid sequence of the protein product.The editing of the atp9 transcript from Ying Xiang B was found to change an arginine codon into a termination codon,shortening the protein of Ying Xiang B to the"standard"size.The Ying Xiang A transcript,which has no termination codon,cannot be translated to a normal protein.The results demonstrate the important role of RNA editing in the production of the functional ATP9 subunit and suggest that RNA editing could be likely associated with cytoplasmic male sterility.