Rice type I phytochrome regulates hypocotyl elongation in transgenic tobacco seedlings.
Rice type I phytochrome regulates hypocotyl elongation in transgenic tobacco seedlings.
复制标题
水稻 I 型光敏色素调节转基因烟草幼苗的下胚轴伸长。
DOI：
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发表时间：
1991
影响因子：
11.1
通讯作者：
M. Furuya
中科院分区：
文献类型：
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作者：
A. Nagatani;S. Kay;M. Deák;N. Chua;M. Furuya
我们研究了水稻I型光敏色素（PI）在转基因烟草幼苗中的生物活性。在弱白色光（0.04 W/m2）下，4个表达水稻PI基因的独立转化体的后代以3：1的比例分离，下胚轴长度较短。相比之下，在黑暗中或在较高强度（6.0 W/m2）的白色光下均未观察到该表型。这表明表型不仅取决于光，还取决于光强度。增加的光敏感性与卡那霉素抗性标记以及水稻PI多肽共分离，表明这种表型与转基因的表达直接相关。显示短下胚轴的转基因植物在整个伸长期间表现出降低的生长速率，并且所得到的较短的下胚轴长度可归因于较短的表皮细胞长度而不是细胞数量减少。此外，连续脉冲照射与红光引起短下胚轴下获得的昏暗的白色光下，效果被立即远红光治疗逆转，提供了一个直接的指示，表型是由生物活性水稻PI。因此，引入的水稻PI的远红外吸收形式似乎通过内源信号转导途径调节转基因烟草植物的下胚轴长度。该检测系统将成为检测导入光敏色素分子生物活性的有力工具。
We have examined the biological activity of rice type I phytochrome (PI) in transgenic tobacco seedlings. The progeny of four independent transformants that expressed the rice PI gene segregated 3:1 for shorter hypocotyl length under dim white light (0.04 W/m2). By contrast, this phenotype was not observed either in the dark or under white light at higher intensity (6.0 W/m2). This suggests that the phenotype is dependent not only on light but also on light intensity. The increased light sensitivity cosegregated with the kanamycin-resistance marker as well as with the rice PI polypeptides, indicating that this phenotype is directly related to the expression of the transgene. The transgenic plants showing short hypocotyls exhibited a reduced growth rate throughout the elongation period, and the resulting shorter hypocotyl length was attributable to shorter epidermal cell length but not to reduced cell number. Furthermore, successive pulse irradiations with red light elicited short hypocotyls similar to those obtained under dim white light, and the effect was reversed by immediate far-red light treatment, providing a direct indication that the phenotype is caused by biologically active rice PI. Therefore, the far-red-absorbing form of the introduced rice PI appears to regulate the hypocotyl length of the transgenic tobacco plants through endogenous signal-transduction pathways. This assay system will be a powerful tool for testing the biological activity of introduced phytochrome molecules.