Himi S, Sano R, Nishiyama T, Tanahashi T, Kato M, Ueda K, Hasebe M
Department of Biology, Faculty of Science, Kanazawa University, Kanazawa 920-1192, Japan.
J Mol Evol. 2001 Oct-Nov;53(4-5):387-93. doi: 10.1007/s002390010228.
Some MADS-box genes function as floral homeotic genes. The Arabidopsis LFY gene is a positive regulator of floral homeotic genes, and homologs of the FLO/LFY gene family in other angiosperms and gymnosperms are likely to have a similar function. To investigate the origin of the floral homeotic gene regulatory cascade involving the FLO/LFY gene, FLO/LFY homologs were cloned from a leptosporangiate fern (Ceratopteris richardii), two eusporangiate ferns (Angiopteris lygodiifolia and Botrychium multifidum var. robustum), three fern allies (Psilotum nudum, Equisetum arvense, and Isoetes asiatica), and a moss (Physcomitrella patens). The FLO/LFY gene phylogenetic tree indicates that both duplication and loss of FLO/LFY homologs occurred during the course of vascular plant evolution. The expression patterns of the Ceratopteris LFY genes (CrLFY1 and 2) were assessed. CrLFY1 expression was prominent in tissues including shoot tips and circinate reproductive leaves, but very weak in other tissues examined. Expression of CrLFY2 was also prominent in tissues, including shoot tips and circinate reproductive leaves. These patterns of expression are dissimilar to that of any Ceratopteris MADS-box gene previously reported, suggesting that the induction of MADS-box genes by FLO/LFY is not established at the stage of ferns.
一些MADS盒基因作为花同源异型基因发挥作用。拟南芥LFY基因是花同源异型基因的正向调节因子，其他被子植物和裸子植物中FLO/LFY基因家族的同源物可能具有类似功能。为了研究涉及FLO/LFY基因的花同源异型基因调控级联的起源，从一种薄囊蕨（里氏满江红）、两种厚囊蕨（阔叶观音座莲和粗壮瓶尔小草变种）、三种蕨类植物近缘种（松叶蕨、问荆和亚洲水韭）以及一种苔藓（小立碗藓）中克隆了FLO/LFY同源物。FLO/LFY基因系统发育树表明，FLO/LFY同源物在维管植物进化过程中既发生了复制也发生了丢失。对满江红LFY基因（CrLFY1和2）的表达模式进行了评估。CrLFY1在包括茎尖和拳卷生殖叶在内的组织中表达显著，但在其他检测组织中非常弱。CrLFY2在包括茎尖和拳卷生殖叶在内的组织中表达也很显著。这些表达模式与先前报道的任何满江红MADS盒基因都不同，这表明在蕨类植物阶段，FLO/LFY对MADS盒基因的诱导尚未确立。
