Huq E, Kang Y, Halliday K J, Qin M, Quail P H
Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA.
Plant J. 2000 Aug;23(4):461-70. doi: 10.1046/j.1365-313x.2000.00810.x.
As part of an effort to isolate new Arabidopsis mutants specifically defective in responsiveness to red light, we identified srl1 (short hypocotyl in red light) by screening an EMS-mutagenized M2 population derived from a phytochrome B (phyB)-overexpressor line (ABO). The srl1 mutant shows enhanced responsiveness to continuous red but not far-red light, in both wild-type and ABO backgrounds, consistent with involvement in the phyB-signaling pathway but not that of phyA. The hypersensitive phenotype of srl1 is not due to overexpression of endogenous phyA or phyB, and the locus maps to the center of chromosome 2, distinct from any other known photomorphogenic mutants. srl1 seedlings display enhancement of several phyB-mediated responses, including shorter hypocotyls, more expanded cotyledons, shorter petioles and modestly higher levels of CAB gene expression under red light than the wild type. Double mutant analyses show that the hypersensitive phenotype of srl1 is completely phyB-dependent. The data suggest, therefore, that SRL1 may encode a negatively acting component specific to the phyB-signaling pathway.
作为分离对红光反应特别缺陷的新拟南芥突变体工作的一部分，我们通过筛选来自一个过表达光敏色素B（phyB）的株系（ABO）经甲基磺酸乙酯（EMS）诱变的M2群体，鉴定出了srl1（红光下短胚轴）。在野生型和ABO背景中，srl1突变体对连续红光而非远红光显示出增强的反应，这与它参与phyB信号通路而非phyA信号通路一致。srl1的超敏表型并非由于内源性phyA或phyB的过表达，并且该基因座定位于第2号染色体的中心，与任何其他已知的光形态建成突变体不同。srl1幼苗在红光下显示出几种phyB介导的反应增强，包括胚轴更短、子叶更展开、叶柄更短以及CAB基因表达水平比野生型略高。双突变分析表明，srl1的超敏表型完全依赖于phyB。因此，数据表明SRL1可能编码phyB信号通路特有的负调控成分。
