Pedicel development in Arabidopsis thaliana:: Contribution of vascular positioning and the role of the BREVIPEDICELLUS and ERECTA genes
Pedicel development in Arabidopsis thaliana:: Contribution of vascular positioning and the role of the BREVIPEDICELLUS and ERECTA genes
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DOI：
10.1016/j.ydbio.2005.06.011
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发表时间：
2005-08-15
影响因子：
2.7
通讯作者：
Riggs, CD
中科院分区：
文献类型：
--
作者：
Douglas, SJ;Riggs, CD
虽然拟南芥花分生组织模式的调控和确定性已经得到了详细的研究，但对花梗发育的遗传机制知之甚少。花梗是连接花和花序轴的短茎。在这里，我们提供的证据表明，花梗由幼花原基的近端部分和远端凸起的区域组成，该凸起的远端区域来自花蕾中的药片底部的组织。远端花梗的生长受KNOTTED1-like Homeobox基因BREVIPEDICELLUS(BP)的控制，因为35S：：BP植株表现出花梗组织的过度增殖，而BP的丢失则导致远端花梗周径向收缩。突变的放射状收缩沿椎弓根的远轴和外侧突出，导致椎弓根远端偶尔向下弯曲。这一效应在丧失功能的直立体(ER)背景中被严重增强，导致沿着花梗的整个远轴侧的放射状收缩组织以及向下定向的花和果实。对椎弓根血管模式的分析显示，血管系统偏向远轴一侧，这与BP和ER在调节血管携带的生长抑制信号中的作用是一致的。BP在一条报告线上的表达标记了花序茎和侧器官以及花托和花器官之间的界限。这种边界表达对于防止结节和侧器官命运的同源移位到下面的干细胞组织中似乎是重要的。为了研究花梗和花发育之间的相互作用，我们将BP-Er杂交到不同的花突变背景中。BP内侧向弯曲的形成与叶序的变化平行，这与突变茎的结构受器官位置和血管形成模式控制的模型一致。综上所述，我们的结果表明，BP基因在拟南芥茎中的作用是提供一种生长能力状态，这种状态抵消了侧器官相关的不对称性，并有效地辐射了节间和花梗的生长和分化模式。(C)2005 Elsevier Inc.保留所有权利。
Although the regulation of Arabidopsis floral meristem patterning and determinacy has been studied in detail, very little is known about the genetic mechanisms directing development of the pedicel, the short stem linking the flower to the inflorescence axis. Here, we provide evidence that the pedicel consists of a proximal portion derived from the young flower primordium, and a bulged distal region that emerges from tissue at the bases of sepals in the floral bud. Distal pedicel growth is controlled by the KNOTTED1-like homeobox gene BREVIPEDICELLUS (BP), as 35S::BP plants show excessive proliferation of pedicel tissue, while loss of BP conditions a radial constriction around the distal pedicel circumference. Mutant radial constrictions project proximally along abaxial and lateral sides of pedicels, leading to occasional downward bending at the distal pedicel. This effect is severely enhanced in a loss-of-function erecta (er) background, resulting in radially constricted tissue along the entire abaxial side of pedicels and downward-oriented flowers and fruit. Analysis of pedicel vascular patterns revealed biasing of vasculature towards the abaxial side, consistent with a role for BP and ER in regulating a vascular-borne growth inhibitory signal. BP expression in a reporter line marked boundaries between the inflorescence stem and lateral organs and the receptacle and floral organs. This boundary expression appears to be important to prevent homeotic displacement of node and lateral organ fates into underlying stem tissue. To investigate interactions between pedicel and flower development, we crossed bp er into various floral mutant backgrounds. Formation of laterally-oriented bends in bp er pedicels paralleled phyllotaxy changes, consistent with a model where the architecture of mutant stems is controlled by both organ positioning and vasculature patterns. Collectively, our results indicate that the BP gene acts in Arabidopsis stems to confer a growth-competent state that counteracts lateral-organ associated asymmetries and effectively radializes internode and pedicel growth and differentiation patterns. (c) 2005 Elsevier Inc. All rights reserved.