cDNA microarray analysis of gene expression during Fe-deficiency stress in barley suggests that polar transport of vesicles is implicated in phytosiderophore secretion in Fe-deficient barley roots.
To acquire Fe from soil, graminaceous plants secrete mugineic acid family phytosiderophores (MAs) from their roots. The secretion of MAs increases in response to Fe deficiency, and shows a distinct diurnal rhythm. We used a microarray that included 8987 cDNAs of rice EST clones to examine gene expression profiles in barley roots during Fe-deficiency stress. Approximately 200 clones were identified as Fe-deficiency-inducible genes, of which seven had been identified previously. In order to meet the increased demand for methionine to produce MAs, Fe-deficiency enhances the expression of genes that participate in methionine synthesis, as well as recycling methionine through the Yang cycle. Of these 200 genes, approximately 50 exhibited different transcription levels in Fe-deficient roots at noon and at night. Northern blot analysis of time course experiments confirmed that five of these genes exhibited a diurnal change in their level of expression. The diurnal changes in the expression of these genes suggest that polar vesicle transport is involved in the diurnal secretion of MAs.
Negishi
Takashi
T
Laboratory of Plant Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
Nakanishi
Hiromi
H
Yazaki
Junshi
J
Kishimoto
Naoki
N
Fujii
Fumiko
F
Shimbo
Kanako
K
Yamamoto
Kimiko
K
Sakata
Katsumi
K
Sasaki
Takuji
T
Kikuchi
Shoshi
S
Mori
Satoshi
S
Nishizawa
Naoko K
NK
D001383:Azetidinecarboxylic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D001692:Biological Transport; D015152:Blotting, Northern; D002940:Circadian Rhythm; D018076:DNA, Complementary / Q000235:genetics*; D020224:Expressed Sequence Tags; D020869:Gene Expression Profiling; D001467:Hordeum / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D007501:Iron / Q000494:pharmacology; D000090463:Iron Deficiencies; D008715:Methionine / Q000096:biosynthesis; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D012275:Oryza / Q000235:genetics; D019441:Plant Epidermis / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D017262:Siderophores / Q000378:metabolism
D018076:DNA, Complementary; D017262:Siderophores; D001383:Azetidinecarboxylic Acid; D008715:Methionine; D007501:Iron; C052863:mugineic acid