Shoot meristem size is dependent on inbred background and presence of the maize homeobox gene, knotted1.
Shoot meristem size is dependent on inbred background and presence of the maize homeobox gene, knotted1.
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发表时间：
2000-07
期刊：
影响因子：
4.6
通讯作者：
Erik Vollbrecht;Leonore Reiser;Sarah Hake
中科院分区：
文献类型：
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作者：
Erik Vollbrecht;Leonore Reiser;Sarah Hake
玉米的Kn1基因在分生组织中表达，而在叶片中不表达，包括叶片在分生组织中的起始位置。Kn1的隐性突变已经被描述为限制分枝能力并导致额外的心皮。显性突变提示KN1功能在维持细胞处于未分化状态中起作用。我们利用DS诱导的显性等位基因来筛选由于DS元件的动员而产生的额外的隐性等位基因。对其中一个等位基因的分析揭示了一种新的胚芽表型，在子叶形成后，胚芽启动了零到几个器官，导致植株停滞为幼苗。我们把这种表型称为有限新梢。有限的地上部表型反映了KN1功能的丧失，但其外显性是背景相关的。我们检查了分生组织的大小，发现缺乏KN1功能的植株的分生组织比非突变的兄弟姐妹更短。此外，限制性自交系的分生组织显著短于允许自交系的分生组织，这表明分生组织高度与KN1基因在胚胎中的功能有关。对胚胎发生过程中有限的枝条植株的分析表明，Kn1在枝条分生组织的维持中发挥了作用。我们讨论了Kn1在维持顶端分生组织的形态发生区中的模型。
The knotted1 (kn1) gene of maize is expressed in meristems and is absent from leaves, including the site of leaf initiation within the meristem. Recessive mutations of kn1 have been described that limit the capacity to make branches and result in extra carpels. Dominant mutations suggest that kn1 function plays a role in maintaining cells in an undifferentiated state. We took advantage of a Ds-induced dominant allele in order to screen for additional recessive alleles resulting from mobilization of the Ds element. Analysis of one such allele revealed a novel embryonic shoot phenotype in which the shoot initiated zero to few organs after the cotyledon was made, resulting in plants that arrested as seedlings. We refer to this phenotype as a limited shoot. The limited shoot phenotype reflected loss of kn1 function, but its penetrance was background dependent. We examined meristem size and found that plants lacking kn1 function had shorter meristems than non-mutant siblings. Furthermore, meristems of restrictive inbreds were significantly shorter than meristems of permissive inbreds, implying a correlation between meristem height and kn1 gene function in the embryo. Analysis of limited shoot plants during embryogenesis indicated a role for kn1 in shoot meristem maintenance. We discuss a model for kn1 in maintenance of the morphogenetic zone of the shoot apical meristem.