Sineshchekov Vitaly A, Loskovich Alexander V, Riemann Michael, Nick Peter
Biology Department of the M. V. Lomonosov Moscow State University, Moscow, 119899, Russia.
Photochem Photobiol Sci. 2004 Nov-Dec;3(11-12):1058-62. doi: 10.1039/b406795A. Epub 2004 Oct 19.
Phytochrome (phy) A in its two native isoforms (phyA' and phyA") and the active (Pchlide(655)) and inactive (Pchlide(633)) protochlorophyllides were investigated by low-temperature fluorescence spectroscopy in the tips of rice (Oryza sativa L. Japonica cv Nihonmasari) coleoptiles from wild type (WT) and the jasmonate-deficient mutant hebiba. The seedlings were either grown in the dark or under pulsed (FRp) or continuous (FRc) far-red light (lambda(a) >/= 720 nm) of equal fluences. In the dark, the mutant had a long mesocotyl and a short coleoptile, whereas the situation was reversed under FR: short mesocotyl and long coleoptile, suggesting that the effect is mediated by phyA. Under these conditions the WT displayed a short coleoptile and emergence of the first leaf. In the dark, the spectroscopic and photochemical properties of phyA, its content and the proportion of its two pools, phyA' and phyA", were virtually identical between WT and hebiba. However, the total content of protochlorophyllides was higher in the mutant. Upon illumination with FRc, [phyA] declined in the WT and the ratio between phyA' and phyA" shifted towards phyA". In hebiba, the light-induced decline of [phyA] was less pronounced and the ratio between phyA' and phyA" did not shift. Moreover, in the WT, FRp stimulated the biosynthesis of Pchlide(655), whereas FRc was inhibiting. In contrast, in the mutant, both FRp and FRc stimulated the synthesis of Pchlide(655). This means that FRc caused the opposite effect in hebiba. This difference correlates with a slower photodestruction of primarily the light-labile phyA' pool in hebiba.
通过低温荧光光谱法，对野生型（WT）和茉莉酸缺乏型突变体“hebiiba”的水稻（日本晴）胚芽鞘尖端中的两种天然异构体（phyA'和phyA"）的光敏色素（phy）A以及活性原叶绿素酸酯（Pchlide(655)）和非活性原叶绿素酸酯（Pchlide(633)）进行了研究。幼苗要么在黑暗中生长，要么在等光通量的脉冲（FRp）或连续（FRc）远红光（λa≥720 nm）下生长。在黑暗中，突变体的中胚轴长而胚芽鞘短，而在远红光下情况则相反：中胚轴短而胚芽鞘长，这表明该效应是由phyA介导的。在这些条件下，野生型表现出短的胚芽鞘和第一片叶子的出现。在黑暗中，野生型和“hebiiba”之间phyA的光谱和光化学性质、其含量以及其两个库phyA'和phyA"的比例实际上是相同的。然而，突变体中原叶绿素酸酯的总含量更高。在用FRc照射后，野生型中[phyA]下降，phyA'和phyA"之间的比例向phyA"偏移。在“hebiiba”中，光诱导的[phyA]下降不太明显，phyA'和phyA"之间的比例没有变化。此外，在野生型中，FRp刺激Pchlide(655)的生物合成，而FRc则起抑制作用。相反，在突变体中，FRp和FRc都刺激Pchlide(655)的合成。这意味着FRc在“hebiiba”中产生了相反的效果。这种差异与“hebiiba”中主要是光不稳定的phyA'库的光破坏较慢有关。
