Os02g0765600
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Contents
Annotated Information
Function
Alpha-amylase gene, RAmylA, encodes rice α-amylase isoform A.
Expression
A significant difference in the seed germinability was observed between the two rice cultivars, 'Nipponbare' and 'Suweon 287', under anoxia (i.e., during germination in submerged soil at 18℃), although little difference was seen under aerobic (in air) or hypoxic (in water) conditions. The number of α-amylase isoforms synthesized in germinating seeds was inversely proportional to the O2 concentrations at the early germination stage. The formation of isoform B was promoted by oxygen supply, while isoform H was undetectable if the seeds were unable to germinate. The activity of isoform H was highly correlated with the coleoptile length in the submerged soil at 18℃, indicating that isoform H is a critical factor for seed germination under anoxia. The expression of the rice α-amylase RAmy1A gene was repressed when the seeds germinated under hypoxia or anoxia[1]. Northern blot analysis and RNA-PCR were used to detect the expression of α-amylase genes in various tissues. Alpha-amylase mRNA was abundant in germinating seeds and callus. RAmy1A and RAmy3E were expressed in all tissues and RAmy1A transcript was most abundant in the germinating seeds[2]. And RAmy1A was demonstrated to be sugar tepressed in rice embryos and functional dissection of the promoter of RAmy1A in relation of its sugar-modulated expression was performed[3].
Fig. 1. Effect of glucose on mRNA levels of α-amylase genes (RAmy1A and RAmy3D) in rice embryos. Embryos dissected from the endosperm (control; lane 1) were incubated for 1 day on a glucose-free medium (1 DS, 1 day starvation; lane 2). After 1 day starvation, embryos were incubated for additional 2 days on a glucose-free medium (3 DS, 3 day starvation; lane 3), or for 2 days on a glucose-containing medium at the concentration of 10 mM (+Glc, 10 mM; lane 4), 30 mM (+Glc, 30 mM; lane 5) and 90 mM (+Glc, 90 mM; lane 6). A: Pattern and quantitation of RAmy1A mRNA level. Relative unit is expressed as lane 3: 100. B: Pattern and quantitation of RAmy3D mRNA level. C: Pattern of rRNA level. D: Glucose content in rice embryos used in the experiment. Data were derived from a part of Table 1. Relative glucose content is expressed as lane 6: 100.
Ontology
Gene ontology: The chemical reactions and pathways involve in carbohydrates.
Growth stage ontology: It occurs when the seed coat has imbibed adequate water becoming soft and elastic.
Labs working on this gene
(1) Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
(2) Bioscience Center and Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa-ku, Nagoya 464-8601, Japan
(3)Department of Genetics, University of California Davis, CA 95616, USA
(4)Bioscience Center, Nagoya University, Chikusa-ku, Nagoya 464-8601, Japan
(5)Department of Agriculture, Meijo University, Tenpaku-ku, Nagoya 468, Japan
(6)Department of Crop Plant Biology, University of Pisa, Via Mariscoglio 34, 56124 Pisa, Italy.
References
1. Jirong Huang;Kyoko Toyofuku;Junji Yamaguchi;Shigemi Akita, Expression of α-amylase isoforms and the RAmy1A gene in rice (Oryza sativa L.) during seed germination, and its relationship with coleoptile length in submerged soil, Plant production science, 2000, 3(1): 32-37
2.Ning Huang;Nozomu Koizumi;Stephen Reinl;Raymond L. Rodriguez, Structural organization and differential expression of rice α-amylase genes, Nucleic Acids Research, 1990, 18(23): 7007-7014
3. Akiyoshi Morita;Taka-aki Umemura;Mitsuyo Kuroyanagi;Yuzo Futsuhara;Pierdomenico Perata;Junji Yamaguchi, Functional dissection of a sugar-repressed α-amylase gene (RAmy1A) promoter in rice embryos, FEBS Letters, 1998, 423(1): 81-85
