Rice nicotianamine synthase localizes to particular vesicles for proper function.
Graminaceous plants release mugineic acid family phytosiderophores to acquire iron from the soil. Recently, we reported that particular vesicles are involved in deoxymugineic acid (DMA) and nicotianamine (NA) biosynthesis and in DMA secretion from rice roots. A fusion protein of rice NA synthase 2 (OsNAS2) and synthetic green fluorescent protein (sGFP) was observed in a dot-like pattern, moving dynamically within the cell. OsNAS2 mutated in the tyrosine motif or di-leucine motif, which was reported to be involved in cellular transport, caused a disruption in vesicular movement and vesicular localization, respectively. Unlike OsNAS2, Arabidopsis NA synthases AtNAS1-4 were distributed uniformly in the cytoplasm with no localization in dot-like structures when transiently expressed in tobacco BY-2 cells. Interestingly, Fe deficiency-inducible genes were upregulated in the OsNAS2-sGFP plants, and the amounts of NA and DMA produced and DMA secreted by the OsNAS2-sGFP plants were significantly higher than in those by the non-transformants and domain-mutated lines. We propose a model for OsNAS2-localized vesicles in rice, and discuss why the introduction of OsNAS2-sGFP caused a disturbance in Fe homeostasis.
Graduate School of Agricultural and Life Sciences; The University of Tokyo; Tokyo, Japan.
Tomoko
T
Nozoye
Graduate School of Agricultural and Life Sciences; The University of Tokyo; Tokyo, Japan.
Kyoko
K
Tsunoda
Graduate School of Agricultural and Life Sciences; The University of Tokyo; Tokyo, Japan.
Seiji
S
Nagasaka
Graduate School of Agricultural and Life Sciences; The University of Tokyo; Tokyo, Japan.
Khurram
K
Bashir
Graduate School of Agricultural and Life Sciences; The University of Tokyo; Tokyo, Japan.
Michiko
M
Takahashi
Research Institute for Bioresources and Biotechnology; Ishikawa Prefectural University; Ishikawa, Japan.
Takanori
T
Kobayashi
Graduate School of Agricultural and Life Sciences; The University of Tokyo; Tokyo, Japan.
Hiromi
H
Nakanishi
Graduate School of Agricultural and Life Sciences; The University of Tokyo; Tokyo, Japan; Research Institute for Bioresources and Biotechnology; Ishikawa Prefectural University; Ishikawa, Japan.
Naoko K
NK
Nishizawa
Iron (Fe); daily fluctuation; deoxymugineic acid; green fluorescent protein; mugineic acid family phytosiderophores; nicotianamine; nicotianamine synthase; rice; tyrosine and di-leucine motifs; vesicle transport