A comparative study of the atp9 gene between a cytoplasmic male sterile line and its maintainer line and further development of a molecular marker specific for male sterile cytoplasm in kenaf (Hibiscus cannabinus L.)

Abstract

In this study, the atp8 gene was cloned from the cytoplasmic male sterile (CMS) line UG93A and its maintainer line UG93B in kenaf. Its DNA sequence analysis showed that atp8 containing 480-bp, encoding 159 amino acid residues, and a 9-bp insertion was found at the 3′flanking sequence in UG93A compared with UG93B. The cDNA sequence of atp8 analyzed by RT-PCR indicated that there were five loci edited, but six loci edited in UG93B. The editing frequencies were higher in sterile cytoplasm than in fertile cytoplasm. The relative expression of atp8 analyzed by real-time PCR showed that the expressed level of atp8 in UG93A was lower than that of its maitainer UG93B and its F1 hybrid UG93A/992 (a restore line). Furthermore, based on the difference of the 9-bp differences at the 3′flanking sequence of atp8 between UG93A and UG93B, a molecular marker specific to male sterile cytoplasm was developed, which can be used for indentifying whether any germplasm of kenaf is male sterile cytoplasm or male fertile cytoplasm.