A comparative study of ATPase subunit 9 (Atp9) gene between cytoplasmic male sterile line and its maintainer line in soybeans
ATPase subunit 9 gene (Atp9) is an important functional gene in mitochondria, and is closely related with energy supply. RNA editing of atp9 gene was associated with male sterility in plants. In this study, the atp9 gene in soybeans was cloned from a soybean cytoplasmic male sterile line NJCMS2A and its maintainer line NJCMS2B. Sequence alignment was performed, and protein structures were analyzed and compared between the soybean cytoplasmic male sterile line NJCMS2A and its maintainer line NJCMS2B. The results show that the fragments with identical sequences of atp9 gene were amplified from the genomic DNA of NJCMS2A and NJCMS2B, while the sequences of atp9 were different when they were amplified from cDNAs of NJCMS2A and NJCMS2B. RNA editing of atp9 gene in the maintainer line NJCMS2B was detected with two nucleotide sites (C to U) in the conserved region, leading to conversion of hydrophilic amino acid serine into hydrophobic leucine. No RNA editing was detected in atp9 gene in the male sterile line NJCMS2A. The putative trans-membrane structures of the atp9 proteins were different, and their trans-membrane directions were opposite.
Key words: Soybean, cytoplasmic male sterility, atp9 gene, RNA editing.