Duplicated STM-like KNOX I genes act in floral meristem activity in Eschscholzia californica (Papaveraceae)
Duplicated STM-like KNOX I genes act in floral meristem activity in Eschscholzia californica (Papaveraceae)
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DOI：
10.1007/s00427-013-0446-8
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发表时间：
2013-09-01
影响因子：
2.4
通讯作者：
Gleissberg, Stefan
中科院分区：
文献类型：
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作者：
Stammler, Angelika;Meyer, Sandra S.;Gleissberg, Stefan
在被子植物中，茎尖分生组织是叶和茎的起源，并最终转化为花的分生组织。类打结同源盒基因（KNOX I）是植物茎分生组织形成和维持的重要调控基因。KNOX I基因维持顶端分生组织的未分化状态，并且在叶起始时局部下调。在拟南芥中，KNOX I基因，特别是SHOOTMERISTEMLESS（STM）基因，已被证明可以调控花的发育和心皮的形成。为了进一步了解KNOX I基因在真双子叶植物中的功能进化，我们研究了STM样基因在加州草菇生殖发育中的作用。我们确定了两个直向同源的STM在Scholzia，EcSTM 1和EcSTM 2，这主要是在花组织中表达。相反，KNAT 1/BP样和KNAT 2/6样KNOX I基因主要在营养器官中表达。病毒诱导的基因沉默（VIGS）被用来敲低基因表达，揭示了这两个EcSTM基因是生殖器官形成所必需的。EcSTM 1的沉默导致雌蕊群的损失和雄蕊数量的减少。EcSTM 2-VIGS花具有减少的和有缺陷的雌蕊，并且比在EcSTM 1-VIGS中观察到的雄蕊数量减少更强烈。两个基因的共沉默导致更明显的表型。此外，沉默的EcSTM 2单独或与EcSTM 1一起导致节间伸长的模式改变，有时在其他花的缺陷。我们的数据表明，STM功能存在于拟南芥的某些方面已经演变之前，基础真双子叶植物从核心真双子叶植物。
In angiosperms, the shoot apical meristem is at the origin of leaves and stems and is eventually transformed into the floral meristem. Class I knotted-like homeobox (KNOX I) genes are known as crucial regulators of shoot meristem formation and maintenance. KNOX I genes maintain the undifferentiated state of the apical meristem and are locally downregulated upon leaf initiation. In Arabidopsis, KNOX I genes, especially SHOOTMERISTEMLESS (STM), have been shown to regulate flower development and the formation of carpels. We investigated the role of STM-like genes in the reproductive development of Eschscholzia californica, to learn more about the evolution of KNOX I gene function in basal eudicots. We identified two orthologs of STM in Eschscholzia, EcSTM1 and EcSTM2, which are predominantly expressed in floral tissues. In contrast, a KNAT1/BP-like and a KNAT2/6-like KNOX I gene are mainly expressed in vegetative organs. Virus-induced gene silencing (VIGS) was used to knockdown gene expression, revealing that both EcSTM genes are required for the formation of reproductive organs. Silencing of EcSTM1 resulted in the loss of the gynoecium and a reduced number of stamens. EcSTM2-VIGS flowers had reduced and defective gynoecia and a stronger reduction in the number of stamen than observed in EcSTM1-VIGS. Co-silencing of both genes led to more pronounced phenotypes. In addition, silencing of EcSTM2 alone or together with EcSTM1 resulted in altered patterns of internodal elongation and sometimes in other floral defects. Our data suggest that some aspects of STM function present in Arabidopsis evolved already before the basal eudicots diverged from core eudicots.