Vacuolar SNAREs Function in the Formation of the Leaf Vascular Network by Regulating Auxin Distribution
Vacuolar SNAREs Function in the Formation of the Leaf Vascular Network by Regulating Auxin Distribution
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DOI：
10.1093/pcp/pcp076
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发表时间：
2009-07-01
影响因子：
4.9
通讯作者：
Hara-Nishimura, Ikuko
中科院分区：
文献类型：
--
作者：
Shirakawa, Makoto;Ueda, Haruko;Hara-Nishimura, Ikuko
在正常的叶发育中，已知二维的叶脉图案是通过维管细胞从基本分生组织细胞分化形成的，其方式受生长素的极性流动调节。然而，调节生长素在叶原基中分布的机制在很大程度上是未知的。在这里，我们表明，液泡SNARE（可溶性N-乙基马来酰亚胺敏感因子附着蛋白受体），VAM 3和VTI 11，是所需的叶维管网络的形成在剂量依赖性的方式。这是第一个报告表明，前液泡室（PVC）液泡交通途径是必要的叶维管网络的形成。vam 3 -4是一种VAM 3缺陷型突变体，被发现具有不成熟的血管网络。对VAM 3 -4中DR 5报告基因的分析表明，VAM 3参与了叶原基中最大生长素的正确模式形成。这表明vam 3 -4的未成熟维管网络主要决定于叶原基原形成层形成阶段。生长素的最大值的异常分布是由生长素外排载体PIN 1（PIN-FORMED 1）在叶原基细胞中的非极化定位引起的。VAM 3是PIN 1在叶细胞中正确定位所需的第一个关键蛋白。最后，我们发现，PIN 1蛋白组成型运输到液泡在叶和根细胞。我们的研究结果表明，PVCvacuole途径是必需的生长素的最大值，调节极性定位的PIN 1，这反过来又是必需的叶维管网络的形成。
In normal leaf development, a two-dimensional pattern of leaf veins is known to form by differentiation of vascular cells from ground meristem cells in a manner that is regulated by the polar flow of auxin. However, the mechanisms regulating the distribution of auxin in the leaf primordium are largely unknown. Here we show that vacuolar SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptors), VAM3 and VTI11, are required for the formation of the leaf vascular network in a dosage-dependent manner. This is the first report to show that the pre-vacuolar compartment (PVC)vacuole traffic pathway is required for the formation of the leaf vascular network. vam3-4, a VAM3-defective mutant, was found to have an immature vascular network. An analysis of the DR5 reporter in vam3-4 indicated that VAM3 is involved in the proper pattern formation of auxin maxima in the leaf primordium. This suggests that the immature vascular network in vam3-4 was mainly determined at the stage of procambium formation in the leaf primordium. The abnormal distribution of auxin maxima was caused by the non-polarized localization of the auxin efflux carrier PIN1 (PIN-FORMED 1) in leaf primordium cells. VAM3 is the first key protein which is required for the proper localization of PIN1 in leaf cells. Finally, we found that PIN1 proteins were constitutively transported to vacuoles in leaf and roots cells. Our findings demonstrate that the PVCvacuole pathway is required for the formation of auxin maxima, which regulates the polar localization of PIN1, which, in turn, is required for the formation of the leaf vascular network.