1. Department of Bioscience and Biotechnology, The United Graduate School of Agricultural Sciences; Kagoshima University; Kagoshima 890-8580 Japan
2. PAK Research Center; Okinawa 903-0213 Japan
3. Department of Bioscience and Biotechnology, Faculty of Agriculture; University of the Ryukyus; Senbaru 1 Nishihara-cho, Okinawa 903-0213 Japan