HY8, A NEW CLASS OF ARABIDOPSIS LONG HYPOCOTYL MUTANTS DEFICIENT IN FUNCTIONAL PHYTOCHROME-A
HY8, A NEW CLASS OF ARABIDOPSIS LONG HYPOCOTYL MUTANTS DEFICIENT IN FUNCTIONAL PHYTOCHROME-A
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DOI：
10.1105/tpc.5.1.39
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发表时间：
1993-01-01
期刊：
影响因子：
11.6
通讯作者：
QUAIL, PH
中科院分区：
文献类型：
--
作者：
PARKS, BM;QUAIL, PH
新出现的证据表明，光敏色素家族的光感受器的个别成员可能会调节植物光形态建成的离散方面。我们在这里报告的隔离光敏色素A突变体的拟南芥使用一种新的筛选策略，旨在检测幼苗长下胚轴在长时间的远红光。对10个突变株系的互补分析表明，每个突变株系在一个新的基因座hy 8上代表一个独立的隐性等位基因。免疫印迹和分光光度分析的两个这些线，hy 8 -1和hy 8 -2，表明，而光敏色素B和C的表达在野生型水平，光敏色素A是检测不到的，从而表明，长下胚轴表型显示这些突变体是由光敏色素A缺乏引起的。第三个等位基因，hy 8 -3，表达光谱正常光敏色素A的野生型水平，表明突变，导致生物活性的损失，否则光化学活性感光分子。与生理实验一起，这些数据提供了直接的证据，即内源光敏色素A是负责黄化幼苗的“远红高辐照度响应”，但并没有发挥主要作用，在介导响应延长红色或白色光。由于hy 8和光敏色素B缺陷hy 3突变体分别对延长的红光和远红光表现出相互响应性，证据表明光敏色素A和B在调节幼苗发育中具有不同的光敏作用。
Emerging evidence suggests that individual members of the phytochrome family of photoreceptors may regulate discrete facets of plant photomorphogenesis. We report here the isolation of phytochrome A mutants of Arabidopsis using a novel screening strategy aimed at detecting seedlings with long hypocotyls in prolonged far-red light. Complementation analysis of 10 selected mutant lines showed that each represents an independent, recessive allele at a new locus, designated hy8. Immunoblot and spectrophotometric analyses of two of these lines, hy8-1 and hy8-2, showed that, whereas phytochromes B and C are expressed at wild-type levels, phytochrome A is undetectable, thus indicating that the long hypocotyl phenotype displayed by these mutants is caused by phytochrome A deficiency. A third allele, hy8-3, expresses wild-type levels of spectrally normal phytochrome A, suggesting a mutation that has resulted in loss of biological activity in an otherwise photochemically active photoreceptor molecule. Together with physiological experiments, these data provide direct evidence that endogenous phytochrome A is responsible for the ''far-red high irradiance response'' of etiolated seedlings, but does not play a major role in mediating responses to prolonged red or white light. Because the hy8 and the phytochrome B-deficient hy3 mutants exhibit reciprocal responsivity toward prolonged red and far-red light, respectively, the evidence indicates that phytochromes A and B have distinct photosensory roles in regulating seedling development.