Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan 430070, China.
Proc Natl Acad Sci U S A. 2011 Jul 19;108(29):11836-41. doi: 10.1073/pnas.1100532108. Epub 2011 Jul 5.
Trichomes are universal biological structures originating from the aerial epidermis, which serve as an excellent model to study plant differentiation at the cell level. Although the pathway regulating trichome formation in the Rosids has been well characterized, only very recently a few genes were identified for trichome initiation in the Asterids. In this study, we cloned Woolly (Wo), essential for trichome formation in tomato. Transgenic experiments revealed that the woolly phenotype is caused by the mutation in Wo which encodes a homeodomain protein containing a bZIP motif and a START domain. We identified three alleles of Wo and found that each allele contains a missense mutation, which respectively results in an amino acid substitution at the C terminus. Microarray and expression analysis showed that the expression of a B-type cyclin gene, SlCycB2, is possibly regulated by Wo, which also participates in trichome formation. Suppression of Wo or SlCycB2 expression by RNAi decreased the number of type I trichomes, and direct protein-protein interaction was detected between them, implying that both proteins may work together in the regulation of this type of trichome formation. Cytological observation and Wo transcript analysis in the developing seeds showed that embryo development was also correlated with Wo.
茸毛是起源于气生表皮的普遍生物结构，是研究植物细胞水平分化的极好模型。尽管蔷薇目植物中调控毛发生成的途径已得到很好的描述，但直到最近才在菊目植物中鉴定出几个用于毛发生始的基因。在这项研究中，我们克隆了番茄毛发生成所必需的 Woolly（Wo）。转基因实验表明，wooly 表型是由 Wo 突变引起的，Wo 编码一个含有 bZIP 基序和 START 结构域的同源域蛋白。我们鉴定了三个 Wo 等位基因，发现每个等位基因都含有一个错义突变，分别导致 C 末端的氨基酸取代。微阵列和表达分析表明，B 型细胞周期蛋白基因 SlCycB2 的表达可能受 Wo 调控，而 Wo 也参与毛发生成。通过 RNAi 抑制 Wo 或 SlCycB2 的表达会减少 I 型毛的数量，并且它们之间检测到直接的蛋白质-蛋白质相互作用，这表明这两种蛋白质可能共同作用于这种毛发生成的调控。在发育种子中的细胞学观察和 Wo 转录分析表明，胚胎发育也与 Wo 相关。
