Cytoplasmic Male Sterility-Associated Mitochondrial Gene orf312 Derived from Rice (Oryza sativa L.) Cultivar Tadukan

Background: Cytoplasmic male sterility (CMS) is a trait associated with non-functional pollen or anthers, caused by the interaction between mitochondrial and nuclear genes. Findings: A Tadukan-type CMS line (TAA) and a restorer line (TAR) were obtained by successive backcrossing between the Oryza sativa cultivars Tadukan (a cytoplasmic donor) and Taichung 65 (a recurrent pollen parent). Using Illumina HiSeq, we determined whole-genome sequences of the mitochondria of TAA and screened the mitochondrial genome for the presence of open reading frame (orf) genes specific to this genome. One of these orf genes, orf312, showed differential expression patterns in TAA and TAR anthers at the meiotic and mature stages, with transcript amounts in TAR being less than those in TAA. The orf312 gene is similar to the previously described orf288, a part of which is among the components comprising WA352, a chimeric CMS-associated gene of wild-abortive-type CMS. Conclusions: The orf312 gene is a promising candidate for CMS-associated gene in TAA.