PHOTORESPONSES OF TRANSGENIC ARABIDOPSIS SEEDLINGS EXPRESSING INTRODUCED PHYTOCHROME-B-ENCODING CDNAS - EVIDENCE THAT PHYTOCHROME-A AND PHYTOCHROME-B HAVE DISTINCT PHOTOREGULATORY FUNCTIONS
PHOTORESPONSES OF TRANSGENIC ARABIDOPSIS SEEDLINGS EXPRESSING INTRODUCED PHYTOCHROME-B-ENCODING CDNAS - EVIDENCE THAT PHYTOCHROME-A AND PHYTOCHROME-B HAVE DISTINCT PHOTOREGULATORY FUNCTIONS
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DOI：
10.1046/j.1365-313x.1993.04010019.x
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发表时间：
1993-07-01
期刊：
影响因子：
7.2
通讯作者：
WHITELAM, GC
中科院分区：
文献类型：
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作者：
MCCORMAC, AC;WAGNER, D;WHITELAM, GC
光控制下胚轴伸长已经在两个转基因拟南芥株系中进行了研究，这两个转基因株系含有高水平的光敏色素B，光敏色素B由引入的水稻或拟南芥衍生的cDNA编码，由35 S CaMV启动子驱动。phyB转化株系的黄化幼苗中下胚轴生长的抑制在连续红光（R）的光子注量率下饱和，所述连续红光（R）的光子注量率显著低于抑制同基因野生型（WT）幼苗中生长所需的光子注量率。然而，在连续远红外辐射（FR）下的phyB转基因株系的黄化幼苗下胚轴生长的抑制，表现出与WT相同的注量率的关系。光生长的幼苗的phyB转基因株系响应结束的一天FR的生长加速，在与WT的方式相当。当一天结束时，FR从15分钟的脉冲延长到14小时的连续照射，这种反应是不变的。光生长的，phyB转化的幼苗降低R：FR比的响应也定性类似于WT，即下胚轴和叶柄的伸长生长增加发生在低R：FR量子比下。然而，绝对伸长生长显着低于在所有的R：FR比测试的转基因幼苗比在WT。总之，这些数据表明，过表达光敏色素B的幼苗比WT对R更敏感，但它们对FR的敏感性没有改变。相反，过表达光敏色素A的幼苗比WT对R和FR都更敏感;而光敏色素B缺陷突变体hy 3对R无反应，同时保留WT-这些数据表明，在野生型黄化幼苗光敏色素A介导的连续FR的影响，光敏色素B的连续R的影响。因此，证据支持的结论，这两种分子物种的感光细胞在植物中有不同的调节作用。
The photocontrol of hypocotyl elongation has been studied in two transgenic lines of Arabidopsis thaliana which contain elevated levels of phytochrome B encoded by either an introduced rice- or Arabidopsis-derived cDNA driven by the 35S CaMV promoter. Inhibition of hypocotyl growth in etiolated seedlings of the phyB-transformed lines was saturated at photon fluence rates of continuous red light (R) which were markedly lower than those required for inhibition of growth in seedlings of the isogenic wild-type (WT). Inhibition of hypocotyl growth in etiolated seedlings of the phyB-transgenic lines under continuous far-red irradiation (FR), however, showed the same relationship with fluence rate as WT. Light-grown seedlings of the phyB-transgenic lines responded to end-of-day FR by an acceleration of growth, in a manner comparable with WT. This response was unaltered when the end-of-day FR was extended from a 15 min pulse to 14 h of continuous irradiation. The response of light-grown, phyB-transformed seedlings to decreasing R:FR ratio was also qualitatively similar to WT, i.e. increased elongation growth of the hypocotyl and petioles occurred under low R:FR quantum ratio. However, absolute elongation growth was markedly less in the transgenic seedlings at all R:FR ratios tested than in WT. Together, these data indicate that seedlings over-expressing phytochrome B are more responsive to R than are WT, but are unaltered in their responsiveness to FR. By contrast, seedlings overexpressing phytochrome A are more responsive than WT to both R and FR; whereas the phytochrome B-deficient mutant hy3 is unresponsive to R while retaining WT-like responsiveness to FR. These data indicate that in WT etiolated seedlings phytochrome A mediates the effects of continuous FR, and phytochrome B the effects of continuous R. The evidence thus supports the conclusion that these two molecular species of the photoreceptor have differential regulatory roles in the plant.