Phylogenetic analysis of the "'ECE" (CYC/TB1) clade reveals duplications predating the core eudicots
Phylogenetic analysis of the "'ECE" (CYC/TB1) clade reveals duplications predating the core eudicots
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DOI：
10.1073/pnas.0602827103
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发表时间：
2006-06-13
影响因子：
11.1
通讯作者：
Donoghue, Michael J.
中科院分区：
文献类型：
--
作者：
Howarth, Dianella G.;Donoghue, Michael J.
花的对称性对理解被子植物的进化和生态学具有特殊的意义。来自龙花科（snapdragon及其近缘种）的证据表明，几种TO基因家族转录因子，特别是CYCLOIDEA （CYC）和DICHOTOMA (DICH)，在单对称（双对称）花的花冠和雄蕊中起着确定背侧身份的作用。对蔷薇和asterid被子植物的研究表明，同源的TCP基因可能在背侧同源性中起重要作用，但没有广泛的系统发育背景来确定拷贝数或同源性。在这里，我们比较了已发表的来自菊科动物和菊科动物的数据与新收集的来自毛茛科动物、石竹科动物、石竹科动物和菊科动物的数据，以确定TCIP转录因子“ECE”（CYC/TB1）分支中主要重复的系统发育位置。贝叶斯分析表明，在欧洲经委会分支中有三个主要的“CYC”副本，导致这些副本的复制早于核心副本。CYC1不包含后续的重复，也不可能在花组织中表达。CYC3在几个群体中表现出与CYC2相似的复制模式。利用RT-PCR技术，我们发现在金银花（Caprifoliaceae）的花中，DipsCYC2B在4个背花瓣中表达，而不在腹花瓣中表达。DipsCYC3B在花和花瓣原基中表达，可能在腹瓣中表达最强烈。
Flower symmetry is of special interest in understanding angiosperm evolution and ecology. Evidence from the Antirrhineae (snapdragon and relatives) indicates that several TO gene-family transcription factors, especially CYCLOIDEA (CYC) and DICHOTOMA (DICH), play a role in specifying dorsal identity in the corolla and androecium of monosymmetric (bilateral) flowers. Studies of rosid and asterid angiosperms suggest that orthologous TCP genes may be important in dorsal identity, but there has been no broad phylogenetic context to determine copy number or orthology. Here, we compare published data from rosids and asterids with newly collected data from ranunculids, caryophyllids, Saxifragales, and Asterales to ascertain the phylogenetic placement of major duplications in the "ECE" (CYC/TB1) clade of TCIP transcription factors. Bayesian analyses indicate that there are three major copies of "CYC" in the ECE clade, and that duplications leading to these copies predate the core eudicots. CYC1 contains no subsequent duplications and may not be expressed in floral tissue. CYC3 exhibits similar patterns of duplication to CYC2 in several groups. Using RT-PCR, we show that, in flowers of Lonicera morrowii (Caprifoliaceae), DipsCYC2B is expressed in the four dorsal petals and not in the ventral petal. DipsCYC3B is expressed in flower and petal primordia, possibly most strongly in the ventral petal.