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1.
Plant Physiol ; 129(4): 1473-81, 2002 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12177461

RESUMO

Expression patterns of a rice (Oryza sativa) cytochrome c gene OsCc1 and its promoter activity were characterized in transgenic rice plants. OsCc1 transcripts accumulate in most cell types, but to varying levels. Large amounts of OsCc1 transcripts are found in the roots, calli, and suspension cells, but relatively lower in mature leaves, demonstrating its higher levels of expression in non-photosynthetic tissues. Unlike the human cytochrome c gene, which is responsive to cAMP, OsCc1 expression is not enhanced in various rice tissues after dibutyryl cAMP treatments. OsCc1 promoter was linked to the sgfp gene and its activities in different tissues and cell types of transgenic rice plants were analyzed in comparison with the Act1 and RbcS promoters. OsCc1 promoter directs expression in virtually all organs of transgenic plants including roots, leaves, calli, embryos, and suspension cells, showing a particularly high activity in calli and roots. Activity of the OsCc1 promoter was 3-fold higher than Act1 in calli and roots and comparable with RbcS in leaves, representing a useful alternative to the maize (Zea mays) Ubi1 and the rice Act1 promoters for transgene expression in monocots.


Assuntos
Proteínas de Arabidopsis , Grupo dos Citocromos c/genética , Oryza/genética , Regiões Promotoras Genéticas/genética , Actinas/genética , Actinas/metabolismo , Mapeamento Cromossômico , Técnicas de Cultura , Grupo dos Citocromos c/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Fluorescência Verde , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Dados de Sequência Molecular , Folhas de Planta/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/genética , Plantas Geneticamente Modificadas , Ribulose-Bifosfato Carboxilase/genética , Ribulose-Bifosfato Carboxilase/metabolismo , Análise de Sequência de DNA
2.
Plant Physiol ; 131(2): 516-24, 2003 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12586876

RESUMO

Trehalose plays an important role in stress tolerance in plants. Trehalose-producing, transgenic rice (Oryza sativa) plants were generated by the introduction of a gene encoding a bifunctional fusion (TPSP) of the trehalose-6-phosphate (T-6-P) synthase (TPS) and T-6-P phosphatase (TPP) of Escherichia coli, under the control of the maize (Zea mays) ubiquitin promoter (Ubi1). The high catalytic efficiency (Seo et al., 2000) of the fusion enzyme and the single-gene engineering strategy make this an attractive candidate for high-level production of trehalose; it has the added advantage of reducing the accumulation of potentially deleterious T-6-P. The trehalose levels in leaf and seed extracts from Ubi1::TPSP plants were increased up to 1.076 mg g fresh weight(-1). This level was 200-fold higher than that of transgenic tobacco (Nicotiana tabacum) plants transformed independently with either TPS or TPP expression cassettes. The carbohydrate profiles were significantly altered in the seeds, but not in the leaves, of Ubi1::TPSP plants. It has been reported that transgenic plants with E. coli TPS and/or TPP were severely stunted and root morphology was altered. Interestingly, our Ubi1::TPSP plants showed no growth inhibition or visible phenotypic alterations despite the high-level production of trehalose. Moreover, trehalose accumulation in Ubi1::TPSP plants resulted in increased tolerance to drought, salt, and cold, as shown by chlorophyll fluorescence and growth inhibition analyses. Thus, our results suggest that trehalose acts as a global protectant against abiotic stress, and that rice is more tolerant to trehalose synthesis than dicots.


Assuntos
Escherichia coli/genética , Glucosiltransferases/genética , Oryza/genética , Monoéster Fosfórico Hidrolases/genética , Trealose/biossíntese , Adaptação Fisiológica/efeitos dos fármacos , Adaptação Fisiológica/genética , Adaptação Fisiológica/fisiologia , Sequência de Aminoácidos , Sequência de Bases , Clorofila/metabolismo , Temperatura Baixa , Desastres , Escherichia coli/enzimologia , Regulação Enzimológica da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Glucosiltransferases/metabolismo , Oryza/crescimento & desenvolvimento , Oryza/metabolismo , Fenótipo , Monoéster Fosfórico Hidrolases/metabolismo , Plantas Geneticamente Modificadas , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Cloreto de Sódio/farmacologia , Nicotiana/efeitos dos fármacos , Nicotiana/genética , Nicotiana/metabolismo , Trealase/metabolismo
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