Zhou Yong-Chun, Dieterle Monika, Büche Claudia, Kretsch Thomas
Albert-Ludwigs-Universität Freiburg, Institut für Biologie 2/Botanik, Schänzlestrasse 1, D-79104 Freiburg, Germany.
Plant Physiol. 2002 Mar;128(3):1098-108. doi: 10.1104/pp.010811.
EID1 (empfindlicher im dunkelroten Licht) and SPA1 (suppressor of phytochrome A[phyA]-105) function as negatively acting components in phyA-specific light signaling. Mutants in the respective genes led to very similar phenotypes under weak-light conditions. To examine whether both genes are functionally redundant, detailed physiological and genetic analyses were performed with eid1 and spa1 mutants isolated from the same wild-type background. Measurements of hypocotyl elongation, anthocyanin accumulation, and Lhcb1-transcript accumulation under different light treatments demonstrated that SPA1 has a strong influence on the regulation of very low fluence responses and a weaker influence on high-irradiance responses. In contrast, EID1 severely altered high-irradiance responses and caused almost no change on very low fluence responses. Analyses on eid1 phyA-105 double mutants demonstrated that EID1 could not suppress the phenotype of the weak phyA allele under continuous far-red light. Measurements on eid1 spa1 double mutants exhibited a strong interference of both genes in the regulation of hypocotyl elongation. These results indicate that EID1 and SPA1 are involved in different but interacting phyA-dependent signal transduction chains.
EID1（在深红色光下敏感）和SPA1（光敏色素A [phyA]-105的抑制因子）在phyA特异性光信号传导中作为负向作用成分发挥功能。各自基因的突变体在弱光条件下导致非常相似的表型。为了研究这两个基因在功能上是否冗余，我们对从相同野生型背景中分离出的eid1和spa1突变体进行了详细的生理和遗传分析。在不同光照处理下对下胚轴伸长、花青素积累和Lhcb1转录本积累的测量表明，SPA1对极低光通量反应的调节有强烈影响，而对高辐照度反应的影响较弱。相比之下，EID1严重改变了高辐照度反应，而对极低光通量反应几乎没有影响。对eid1 phyA-105双突变体的分析表明，在连续远红光下，EID1不能抑制弱phyA等位基因的表型。对eid1 spa1双突变体的测量显示，这两个基因在下胚轴伸长调节中存在强烈干扰。这些结果表明，EID1和SPA1参与不同但相互作用的phyA依赖性信号转导链。
