Evolutionary alterations in gene expression and enzymatic activities of gibberellin 3-oxidase 1 in Oryza
Kyosuke Kawai, Sayaka Takehara, Toru Kashio, Minami Morii, Akihiko Sugihara, Hisako Yoshimura, Aya Ito, Masako Hattori, Yosuke Toda, Mikiko Kojima, Yumiko Takebayashi, Hiroyasu Furuumi, Ken-ichi Nonomura, Bunzo Mikami, Takashi Akagi, Hitoshi Sakakibara, Hidemi Kitano, Makoto Matsuoka & Miyako Ueguchi-Tanaka
Communications Biology (2022) 5, 67 DOI:10.1038/s42003-022-03008-5
The plant hormone gibberellin (GA) plays important roles in various developmental events, such as stem elongation, induction of seed germination and flowering. Although GA is indispensable for anther and pollen development, our knowledge of GA functions during plant reproduction has been limited to date.
This paper reports the functional and evolutionary analyses of rice gibberellin 3-oxidase 1 (OsGA3ox1), a gibberellin synthetic enzyme specifically expressed in the late developmental stages of anthers. Enzymatic and X-ray crystallography analyses reveal that OsGA3ox1 has a higher GA7 synthesis ratio than OsGA3ox2. In addition, we generate an osga3ox1 knockout mutant by genome editing and demonstrate the bioactive gibberellic acid synthesis by the OsGA3ox1 action during starch accumulation in pollen via invertase regulation. Furthermore, we analyze the evolution of Oryza GA3ox1s and reveal that their enzyme activity and gene expression have evolved in a way that is characteristic of the Oryza genus and contribute to their male reproduction ability.
In this paper, we used the wild strains of genus Oryza that NIG has conserved with the support of National Bioresource Project (NBRP) Rice, Ministry of Education, Culture, Sports, Science and Texhnology (MEXT), Japan.