The expression of iron homeostasis-related genes during rice germination.
To characterize Fe homeostasis during the early stages of seed germination, a microarray analysis was performed. mRNAs extracted from fully mature seeds or seeds harvested 1-3 days after sowing were hybridized to a rice microarray containing approximately 22,000 cDNA oligo probes. Many Fe deficiency-inducible genes were strongly expressed throughout early seed germination. These results suggest that the demand for Fe is extremely high during germination. Under Fe-deficient conditions, rice produces and secretes a metal-cation chelator called deoxymugineic acid (DMA) to acquire Fe from the soil. In addition, DMA and its intermediate nicotianamine (NA) are thought to be involved in long distance Fe transport in rice. Using promoter-beta-glucuronidase (GUS) analysis, we investigated the expression patterns during seed germination of the Fe deficiency-inducible genes OsNAS1, OsNAS2, OsNAS3, OsNAAT1, and OsDMAS1, which encode enzymes that participate in the biosynthesis of DMA, and the transporter genes OsYSL2 and OsIRT1, which are involved in Fe transport. All of these genes were expressed in germinating seeds prior to protrusion of the radicle. These results suggest that DMA and NA are produced and involved in Fe transport during germination.
Nozoye
Tomoko
T
Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
Inoue
Haruhiko
H
Takahashi
Michiko
M
Ishimaru
Yasuhiro
Y
Nakanishi
Hiromi
H
Mori
Satoshi
S
Nishizawa
Naoko K
NK
D001383:Azetidinecarboxylic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D001692:Biological Transport / Q000235:genetics; D018525:Germination; D005966:Glucuronidase / Q000032:analysis; D006706:Homeostasis; D007501:Iron / Q000378:metabolism*; D033862:Iron-Binding Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D012275:Oryza / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D010940:Plant Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000254:growth & development / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000032:analysis; D012639:Seeds / Q000235:genetics / Q000254:growth & development / Q000378:metabolism
D033862:Iron-Binding Proteins; D010940:Plant Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; C082893:nicotianamine; D001383:Azetidinecarboxylic Acid; D007501:Iron; D005966:Glucuronidase; C052863:mugineic acid