Interallelic complementation at the Arabidopsis CRE1 locus uncovers independent pathways for the proliferation of vascular initials and canonical cytokinin signalling
Interallelic complementation at the Arabidopsis CRE1 locus uncovers independent pathways for the proliferation of vascular initials and canonical cytokinin signalling
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DOI：
10.1111/j.1365-313x.2004.02023.x
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发表时间：
2004-04-01
期刊：
影响因子：
7.2
通讯作者：
Leyva, A
中科院分区：
文献类型：
--
作者：
de León, BGP;Zorrilla, JMF;Leyva, A
维管组织的分化在根的构型和功能中起着重要作用。不管它的重要性，参与血管形态发生的开始及其与激素的相互作用的分子机制现在才开始被理解。WOODEN LEG（WOL/CRE 1突变体）的特征，受损的原形成层细胞增殖和WOL/CRE 1作为细胞分裂素受体的鉴定，提供了第一个遗传证据，指出细胞分裂素在血管起始的形成中的作用。然而，在所有可用的cre 1等位基因集合中，血管分化中显著的wol表型是唯一的。在这项工作中，我们确定了一个突变体具有相同的缺陷，在血管分化的wol。互补分析表明，该突变体挽救了wol短根表型。然而，突变体的遗传特征表明，突变位于CRE 1位点，这表明两个等位基因显示等位基因间互补。反式杂合子的特征表明，这些植物完全恢复了在维管分化的缺陷，但不是典型的细胞分裂素信号。此外，我们表明，根生长抑制，愈伤组织再生测定和北方分析，原来的wol等位基因实际上是更敏感的细胞分裂素比反式杂合植物，或一些cre 1等位基因显示野生型维管形态发生。因此，在cre 1/wol等位基因和经典细胞分裂素信号传导所显示的血管分化表型之间没有严格的相关性。这些结果表明，至少部分独立的监管电路可能会在原形成层细胞增殖和细胞分裂素的反应，通过CRE 1受体发挥作用。
The differentiation of vascular tissue plays a central role in root architecture and its functionality. Regardless of its importance, the molecular mechanisms involved in the inception of vascular morphogenesis and their interaction with hormones are only now beginning to be understood. The characterisation of the WOODEN LEG (wol/cre1 mutant), impaired in procambial cell proliferation and the identification of WOL/CRE1 as a cytokinin receptor, provided the first genetic evidence pointing to a role of cytokinins in the formation of vascular initials. However, the striking wol phenotype in vascular differentiation is unique among all the available cre1 alleles collection. In this work, we identified a mutant with identical deficiencies in vascular differentiation as wol. Complementation analysis revealed that this mutant rescued the wol short-root phenotype. However, genetic characterisation of the mutant showed that the mutation was located at the CRE1 locus, indicating that both alleles displayed interallelic complementation. Trans-heterozygotes characterisation showed that these plants fully restored the deficiency in vascular differentiation but not the canonical cytokinin signalling. Furthermore, we show that, as measured in root growth inhibition, calli regeneration assays and northern analysis, the original wol allele is in fact more sensitive to cytokinins than the trans-heterozygous plants, or some cre1 alleles showing wild-type vascular morphogenesis. Thus, there is no strict correlation between the phenotype in vascular differentiation displayed by the cre1/wol alleles and canonical cytokinin signalling. These results indicate that at least partially independent regulatory circuits may operate in procambial cell proliferation and in cytokinin responsiveness exerted through the CRE1 receptor.