Kwok S F, Piekos B, Misera S, Deng X W
Graduate Program of Genetics, Yale University School of Medicine, New Haven, Connecticut 06520-8005, USA.
Plant Physiol. 1996 Mar;110(3):731-42. doi: 10.1104/pp.110.3.731.
Two genetic screens, one for mutations resulting in photomorphogenic development in darkness and the other for mutants with fusca phenotype, have thus far identified six pleiotropic Arabidopsis COP/DET/FUS genes. Here, we characterized representative mutants that define four additional pleiotropic photomorphogenic loci and a null mutant allele of the previously defined DET1 locus. Dark-grown seedlings homozygous for these recessive mutations exhibit short hypocotyls and expanded cotyledons and are lethal before reaching reproductive development. Dark-grown mutant seedlings also display characteristic photomorphogenic cellular differentiation and elevated expression of light-inducible genes. In addition, analyses of plastids from dark-grown mutants reveal partial chloroplast differentiation and absence of etioplast development. Root vascular bundle cells of light-grown mutant seedlings develop chloroplasts, suggesting that these FUS gene products are important for suppression of chloroplast differentiation in light-grown roots. Double-mutant analyses indicate that these pleiotropic cop/det/fus mutations are epistatic to mutations in phytochromes, a blue-light photoreceptor, and a downstream regulatory component, HY5. Therefore, there is a complement of at least 10 essential and pleiotropic Arabidopsis genes that are necessary for repression of photomorphogenic development.
到目前为止，两项基因筛选，一项针对导致黑暗中光形态建成发育的突变，另一项针对具有fusca表型的突变体，已经鉴定出六个拟南芥多效性COP/DET/FUS基因。在这里，我们对代表四个额外多效性光形态建成位点的代表性突变体以及先前定义的DET1位点的一个无效突变等位基因进行了表征。这些隐性突变纯合的黑暗生长幼苗表现出短的下胚轴和扩展的子叶，并且在达到生殖发育之前是致死的。黑暗生长的突变幼苗还表现出特征性的光形态建成细胞分化和光诱导基因的表达升高。此外，对黑暗生长突变体的质体分析揭示了部分叶绿体分化和黄化质体发育的缺失。光照生长的突变幼苗的根维管束细胞发育出叶绿体，这表明这些FUS基因产物对于抑制光照生长根中的叶绿体分化很重要。双突变分析表明，这些多效性cop/det/fus突变对光敏色素、蓝光光受体和下游调节成分HY5中的突变具有上位性。因此，至少有10个必需的和多效性的拟南芥基因对于抑制光形态建成发育是必需的。
