Cove David J, Quatrano Ralph S
Centre for Plant Sciences, University of Leeds, Leeds LS2 9JT, UK.
Plant Cell Environ. 2006 Jul;29(7):1379-87. doi: 10.1111/j.1365-3040.2006.01519.x.
New mutants of the moss Ceratodon purpureus have been isolated, which showed abnormal gravitropic responses. The apical cells of protonemal filaments of wild-type strains respond to gravity by growing upwards and are well aligned to the gravity vector. This response only occurs in darkness. Mutants show a range of phenotypes. Some are insensitive to gravity, showing symmetrical growth, while others align to the gravity vector but orient growth downwards. A further class grows in darkness as though it were in light, showing insensitivity to gravity and continued chlorophyll synthesis. Somatic hybrids between mutants and wild-type strains and between pairs of mutants have been selected using transgenic antibiotic resistance as selective markers. Hybrids between wild-type strains and all of the mutants have a wild-type phenotype, and so all mutants therefore have recessive phenotypes. Mutants comprise three complementation groups. One group has a single member, while another has three members. The third has at least 16 members and shows a complex pattern of complementation consistent with a single gene product functioning in both orientation and alignment to gravity, as well as contributing more than one subunit to the mature product.
已分离出紫萼藓（Ceratodon purpureus）的新突变体，这些突变体表现出异常的向重力性反应。野生型菌株原丝体细丝的顶端细胞通过向上生长对重力作出反应，并与重力向量良好对齐。这种反应仅在黑暗中发生。突变体表现出一系列表型。一些对重力不敏感，表现出对称生长，而另一些则与重力向量对齐但向下定向生长。另一类在黑暗中生长，就好像处于光照下一样，表现出对重力不敏感并持续进行叶绿素合成。利用转基因抗生素抗性作为选择标记，筛选出了突变体与野生型菌株之间以及突变体对之间的体细胞杂种。野生型菌株与所有突变体之间的杂种具有野生型表型，因此所有突变体都具有隐性表型。突变体分为三个互补群。一组有一个成员，另一组有三个成员。第三组至少有16个成员，显示出复杂的互补模式，这与单个基因产物在重力定向和对齐中起作用一致，并且对成熟产物贡献不止一个亚基。
