作者：中国教育和科研计算机网 来源：中国教育和科研计算机网 2011-7-21 14:38:42
7月6日，美国《国家科学院院刊》(PNAS)上在线发表了华中农业大学一项最新研究成果——番茄表皮毛形成及胚胎致死的调控机制(A regulatory gene induces trichome formation and embryo lethality in tomato)。论文的第一作者为华中农业大学园艺林学学院的硕博连读生杨长宪，通讯作者为该院叶志彪教授。
该研究通过图位克隆的方法分离并鉴定了番茄多细胞表皮毛形成的关键基因—Woolly (Wo)，并深入研究了该基因参与番茄表皮毛形成的调控途径，即Wo通过蛋白互作的方式促进细胞周期相关基因—SlCycB2 的表达，从而促使细胞从G2期向M期的转换，最终促进表皮毛的形成。同时，由于Wo基因纯合后会导致番茄胚胎的败育，因此该基因的分离对于揭示番茄胚胎发育的机理也具有重要意义。
陆地植物表皮毛起始于植物表皮细胞，它们有单细胞和多细胞两种类型。表皮毛作为研究植物细胞命运调控的模式系统，越来越受到人们的重视。拟南芥表皮毛作为典型的单细胞结构，其调控机制已经进行了深入的研究，即通过MYB-bHLH-WD40 蛋白复合体调节下游基因的表达，从而控制表皮毛的分化发育。棉花纤维与拟南芥表皮毛发生机制相似。但是，番茄、矮牵牛、烟草等体表的多细胞表皮毛起始分化的调控机制可能不同。该文报道的研究结果显示番茄表皮毛形成的调控模式不同于拟南芥表皮毛，是一种新的调控机制。该机制的发现对于揭示植物细胞命运调控的多样性具有十分重要的价值。
另外，番茄表皮毛在抵抗蚜虫及其传播的黄瓜花叶病毒、烟草花叶病毒、黄化曲叶病毒等方面发挥重要作用。目前我国已培育出多个多毛番茄品种应用于生产，但因多毛的发生与胚胎纯合子致死相关联，所培育出来的番茄一代杂交品种总是为“多毛”和“无毛”两类植株的混合群体，种植需剔除“无毛”的植株。该研究对破解“多毛”与“纯合子致死”难题奠定了基础
推荐原文出处：
Proceedings of the National Academy of Sciences doi:10.1073/pnas.1100532108
A regulatory gene induces trichome formation and embryo lethality in tomato
Changxian Yang, Hanxia Li, Junhong Zhang, Zhidan Luo, Pengjuan Gong, Chanjuan Zhang, Jinhua Li, Taotao Wang, Yuyang Zhang, Yong'en Lu, and Zhibiao Ye
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.
