Differential control of xanthophylls and light-induced stress proteins, as opposed to light-harvesting chlorophyll a/b proteins, during photosynthetic acclimation of barley leaves to light irradiance
Differential control of xanthophylls and light-induced stress proteins, as opposed to light-harvesting chlorophyll a/b proteins, during photosynthetic acclimation of barley leaves to light irradiance
复制标题
在大麦叶片光合适应光辐照度过程中，叶黄素和光诱导应激蛋白（与光捕获叶绿素 a/b 蛋白相反）的差异控制
作者：
M. Montané;Florence Tardy;K. Kloppstech;M. Havaux
大麦（Hordeum vulgare L.）在空气和/或具有降低水平的O2和CO2的气氛中，植物在100至1800 molm-2s-1范围内的不同光子通量密度下生长。低O2和CO2分压允许植物在高的光系统II（PSII）激发压力下生长，估计在体内叶绿素荧光测量，在中等的光子通量密度。叶黄素循环色素，早期光诱导蛋白，和它们的mRNA积累与PSII激发压力的增加，无论高激发压力的方式获得（高光辐照度或降低CO2和O2的可用性）。这些结果表明，电子传递链组分的还原状态可能参与了光感受核编码的叶绿体基因表达的调控。与此相反，没有发现PSII的还原状态和PSII捕光系统的各种指标之间的相关性，如叶绿素a-到-B的比例，丰富的主要色素-蛋白质复合物的PSII（LHCII），LHCII的mRNA水平，光饱和曲线的O2演变，和诱导叶绿素荧光上升。我们的结论是，PSII的叶绿素天线的大小是不受PSII在高等植物中的氧化还原状态，因此，早期光诱导蛋白质合成的调节是不同的LHCII。
Barley (Hordeum vulgare L.) plants were grown at different photon flux densities ranging from 100 to 1800 &mgr;mol m-2 s-1 in air and/or in atmospheres with reduced levels of O2 and CO2. Low O2 and CO2 partial pressures allowed plants to grow under high photosystem II (PSII) excitation pressure, estimated in vivo by chlorophyll fluorescence measurements, at moderate photon flux densities. The xanthophyll-cycle pigments, the early light-inducible proteins, and their mRNA accumulated with increasing PSII excitation pressure irrespective of the way high excitation pressure was obtained (high-light irradiance or decreased CO2 and O2 availability). These findings indicate that the reduction state of electron transport chain components could be involved in light sensing for the regulation of nuclear-encoded chloroplast gene expression. In contrast, no correlation was found between the reduction state of PSII and various indicators of the PSII light-harvesting system, such as the chlorophyll a-to-b ratio, the abundance of the major pigment-protein complex of PSII (LHCII), the mRNA level of LHCII, the light-saturation curve of O2 evolution, and the induced chlorophyll-fluorescence rise. We conclude that the chlorophyll antenna size of PSII is not governed by the redox state of PSII in higher plants and, consequently, regulation of early light-inducible protein synthesis is different from that of LHCII.