7月6日，美國《國家科學(xué)院院刊》(PNAS)上在線發(fā)表了華中農(nóng)業(yè)大學(xué)一項最新研究成果——番茄表皮毛形成及胚胎致死的調(diào)控機(jī)制(A regulatory gene induces trichome formation and embryo lethality in tomato),。論文的第一作者為華中農(nóng)業(yè)大學(xué)園藝林學(xué)學(xué)院的碩博連讀生楊長憲,，通訊作者為該院葉志彪教授。
該研究通過圖位克隆的方法分離并鑒定了番茄多細(xì)胞表皮毛形成的關(guān)鍵基因—Woolly (Wo),，并深入研究了該基因參與番茄表皮毛形成的調(diào)控途徑,，即Wo通過蛋白互作的方式促進(jìn)細(xì)胞周期相關(guān)基因—SlCycB2 的表達(dá)，從而促使細(xì)胞從G2期向M期的轉(zhuǎn)換,，最終促進(jìn)表皮毛的形成,。同時，由于Wo基因純合后會導(dǎo)致番茄胚胎的敗育，因此該基因的分離對于揭示番茄胚胎發(fā)育的機(jī)理也具有重要意義,。
陸地植物表皮毛起始于植物表皮細(xì)胞,，它們有單細(xì)胞和多細(xì)胞兩種類型。表皮毛作為研究植物細(xì)胞命運(yùn)調(diào)控的模式系統(tǒng),，越來越受到人們的重視,。擬南芥表皮毛作為典型的單細(xì)胞結(jié)構(gòu)，其調(diào)控機(jī)制已經(jīng)進(jìn)行了深入的研究,，即通過MYB-bHLH-WD40 蛋白復(fù)合體調(diào)節(jié)下游基因的表達(dá),，從而控制表皮毛的分化發(fā)育,。棉花纖維與擬南芥表皮毛發(fā)生機(jī)制相似,。但是，番茄,、矮牽牛,、煙草等體表的多細(xì)胞表皮毛起始分化的調(diào)控機(jī)制可能不同。該文報道的研究結(jié)果顯示番茄表皮毛形成的調(diào)控模式不同于擬南芥表皮毛,，是一種新的調(diào)控機(jī)制,。該機(jī)制的發(fā)現(xiàn)對于揭示植物細(xì)胞命運(yùn)調(diào)控的多樣性具有十分重要的價值。
另外,，番茄表皮毛在抵抗蚜蟲及其傳播的黃瓜花葉病毒,、煙草花葉病毒、黃化曲葉病毒等方面發(fā)揮重要作用,。目前我國已培育出多個多毛番茄品種應(yīng)用于生產(chǎn),，但因多毛的發(fā)生與胚胎純合子致死相關(guān)聯(lián)，所培育出來的番茄一代雜交品種總是為“多毛”和“無毛”兩類植株的混合群體,，種植需剔除“無毛”的植株,。該研究對破解“多毛”與“純合子致死”難題奠定了基礎(chǔ)。(生物谷 Bioon.com)
生物谷推薦原文出處：
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.
