Author(s)

So Makabe¹, Htet Aung Htut², Hiroko Takahashi¹, Sayaka Shida², Masahiro Akimoto³, Hathairat Urairong⁴, Ryuji Ishikawa⁵, Tadashi Sato⁶, Yo-Ichiro Sato⁷, Ikuo Nakamura^2*

¹BEX Co Ltd., Tokyo, Japan.
²Graduate School of Horticulture, Chiba University, Matsudo, Japan.
³Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Japan.
⁴Biotechnology Research and Development Office, DOA, Thanyaburi, Thailand.
⁵Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Japan.
⁶Graduate School of Life Sciences, Tohoku University, Sendai, Japan.
⁷Kyoto Prefectural University, Kyoto, Japan.

A wild rice (BKK) strain showing sterile spikelet and big leaves inhabited at the basin of the Chao Phraya river of Bangkok city, Thailand. The BKK strain was found as a natural triploid and thus its origin has been interested long time. Three different-sized fragments were amplified in RNA polymerase I largest subunit (PolA1) gene, which is a single-copy nuclear gene per haploid genome. Short type (0.14 kb) intron 20 sequence of BKK strain was identical to that of O. rufipogon and O. sativa. Phylogenetic analysis showed that long type (1.5 kb and 1.8 kb) intron 20 sequences of BKK strain were closely related to that of O. longistaminata and O. officinalis, respectively. We analyzed protein tag (Ptag) sequence encoded by exons 19 to 21 of PolA1 gene. Determined three Ptag sequences of BKK strain were identical to that of O. rufipogon, O. longistaminata, and O. officinalis, respectively. Relative DNA content of nuclei in O. officinalis and BKK strain was 1.5 and 1.75 times than that in O. sativa, respectively. And BKK strain contained CentO-C1 repeats, which were unique to O. officinalis. These results indicated that BKK strain comprised three genomes of O. rufipogon, O. longistaminata, and O. officinalis.

Oryza rufipogon, Triploid, Flow Cytometry, PolA1, CentO-C1 Repeat Sequence

Makabe, S. , Htut, H. , Takahashi, H. , Shida, S. , Akimoto, M. , Urairong, H. , Ishikawa, R. , Sato, T. , Sato, Y. and Nakamura, I. (2022) Triploid Wild Rice (BKK) Strain Found in Bangkok Originated from Hybridizations among Three Parental Oryza Species. American Journal of Plant Sciences, 13, 36-49. doi: 10.4236/ajps.2022.131003.