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Differential expression of three members of the AMT1 gene family encoding putative high‐affinity NH 4 + transporters in roots of Oryza sativa subspecies indica
Author(s) -
KUMAR A.,
SILIM S. N.,
OKAMOTO M.,
SIDDIQI M. Y.,
GLASS A. D. M.
Publication year - 2003
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1046/j.1365-3040.2003.01023.x
Subject(s) - oryza sativa , photoperiodism , ammonium , seedling , biology , gene , arabidopsis , gene expression , botany , oryza , chemistry , biochemistry , organic chemistry , mutant
In order to investigate the molecular basis of high‐affinity ammonium absorption by roots of rice plants ( Oryza sativa subspecies indica ) the expression patterns of three members of the AMT1 family of genes in rice seedling roots in response to altered nitrogen provision and diurnal changes in irradiance were examined. The 13 NH 4 + influx and transcript levels of OsAMT1.1 in roots decreased several fold within 48 h when plants acclimated to 10 µ m external NH 4 + for 3 weeks were transferred to 10 m m NH 4 + . Likewise when plants acclimated in 10 m m NH 4 + were transferred to 10 µ m NH 4 + , there was an equally rapid up‐regulation of OsAMT1.1 and 13 NH 4 + influx in the roots. Changes in transcript abundance of OsAMT1.2 following these treatments were approximately 50% less than in OsAMT1.1 , and changes of OsAMT1.3 expression were even less. By contrast, in response to the diurnal changes of irradiance, root transcript abundance of OsAMT1.3 and 15 NH 4 + influx increased approximately three‐fold late in the photoperiod, whereas OsAMT1.1 and OsAMT1.2 exhibited only modest changes. The present results suggest that high‐affinity NH 4 + influx is differentially regulated at the transcriptional level through the expression of three members of the OsAMT1 family of genes in roots of rice seedlings in response to changes of N status and daily irradiance. In general, these findings are in agreement with earlier observations in Arabidopsis and tomato.