Poster: Mineral nutrition
Abs #
209: Role of Nicotianamine and Deoxymugineic Acid in Plant Reproductive Development and Embryogenesis
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Presenter: |
Takahashi, Michiko , amichiko@mail.ecc.u-tokyo.ac.jp |
Authors | Takahashi, Michiko (A) Inoue, Haruhiko (A) Tunoda, kyoko (A) Ushio, Yohei (A) Nakanishi, Hiromi (A) Satoshi, Mori (A) Nishizawa, Naoko K. (A) (B) | | Affiliations: |
(A): Graduate School of Agricultural and Life Sciences, University of Tokyo
(B): Core Research for Evolutional Science and Technology
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Nicotianamine aminotransferase (NAAT) is the crucial enzyme in the biosynthetic pathway of mugineic acid family phytosiderophores (MAs), and its activity is induced in response to iron deficiency. NAAT activity has been only detected in graminaceous plants but not in dicot plants. To investigate the consequences of ectopic NAAT production in non-graminaceous plants, transgenic tobacco plants that overexpressed barley NAAT (naat-tobacco) was produced. The naat-tobacco developed a severe interveinal chlorosis in the young leaves and had Fe transport disorders. Nicotianamine (NA) was not detected in these plants. Application of NA-Fe to the naat-tobacco reversed interveinal chlorosis. In addition, grafting of naat-tobacco onto transgenic tobacco overexpressing barley nicotianamine synthase gene (HvNAS1) (nas-tobacco) reversed the chlorosis, abnormal shaped inflorescence and sterility. NtNAS was expressed in inflorescence of wild type tobacco. These results suggested that NA was essential in the development of reproductive organs and seeds’ maturation (Takahashi et al., 2003, 15, 1263-1280, Plant Cell).
Furthermore, to illuminate a role of NA in reproductive development in dicot plants, we investigated the expression of AtNAS in inflorescences and seeds of Arabidopsis using Promoter:β-glucuronidase (GUS) analysis. The expressions of OsNAS and OsNAAT in inflorescences and seeds of rice were also examined. The results indicated that NA and DMA may play a critical role in embryogenesis in addition to a role in metal translocation to inflorescence and seeds.
