Discovery of mitochondrial chimeric-gene associated with cytoplasmic male sterility of HL-rice

The mitochondrial genome libraries of HL-type sterile line(A) and maintainer line(B) have been constructed. Mitochondrial gene, atp6, was used to screen libraries, due to the different Southern and Northern blot results between sterile and maintainer line. Sequencing analysis of positive clones proved that there were two copies of atp6 gene in sterile line and only one in maintainer line. One copy of atpt6 in sterile line was same to that in maintainer line; the other showed different flanking sequence from the 49th nucleotide downstream of the termination codon of atp6 gene. A new chimeric gene, orfH79, was found in the region. OrfH79 had homology to mitochondrial gene cox Ⅱ and orf107, and was special to HL-sterile cytoplasm.

The mitochondrial genome libraries of HL-type sterile line (A) and maintainer line(B) have been constructed. Mitochondrial gene, atp6, was used to screen libraries, due to the different Southern and Northern blot results between sterile and maintainer line. Sequencing analysis of positive clones proved that there were two copies of atp6 gene in sterile line and only one in maintainer line. One copy of atpt6 in sterile line was same to that in maintainer line; the other showed different flanking sequence from the 49th nucleotide downstream of the termination codon of atp6 gene. A new chimeric gene, orfH79, was found in the region. OrfH79 had homology to mitochondrial gene cox II and orf107, and was special to HL-sterile cytoplasm.