A previously reported cytoplasmic male sterilityassociated fragment was detected in chili pepper (Capsicum annuum L.) and sequenced in the mitochondria of a sterile plant. This fragment, 16 kb in size, contains two common mitochondrial genes, coxII and atp6-2, and the newly detected gene orf456, which appears to be a strong candidate gene for the male sterile phenotype. The data show that one nucleotide (Cytosine) at the +449 position is missing compared with the original sequence data of orf456. By translation to the amino acid sequence, the termination codon was found 49 nt downstream from the original site. This hypothetical extension was confirmed by RT-PCR, which showed a sequence size of 507 bp. Since pollen fertility can be restored by a nuclear restorer of fertility gene (Rf), the transcription of orf507 was checked in four stages of flower development. The RT-PCR resulted in a fragment in stage III in the restorer line, indicating a possible role in microspore development.

Zinc (Zn) is an essential element for humans as well as for plants. Sweet potato is a major staple crop in the world, and is an attractive target crop for genetic engineering because its suitability for clonal propagation and its selfincompatibility. OsZIP4 is a rice Zn transporter that increases Zn concentrations, especially in roots, when it is artificially overexpressed in rice. In our study we induced an embryogenic callus from the apex of sweet potato (Ipomoea batatas L. Lam. cv. Kokei No. 14), and obtained OsZIP4 overexpressed lines driven by the CaMV35S promoter through Agrobacterium infection. Three transgenic lines were confirmed by RT-PCR for their OsZIP4 expression in roots and leaves. Zn concentrations in roots and leaves of OsZIP4 transgenic plants grown on LS medium were approximately 2.3 times and 1.3 times higher, respectively than those of wild type plants. In addition, the iron content of tubers was two times higher than wild type (WT) lines, and that of leaves was up to 1.2 times higher. Root tubers of transgenic lines were obtained under soil culture. The Zn concentration of transgenic sweet potato tubers was 2.2 times higher than WT lines, but there were no differences in shoot length or fresh weight between the transgenic and WT lines. These results indicate that introducing the OsZIP4 gene in to sweet potato is a potential method to improve the Zn nutrition of livestock and humans.