Root System Architecture in Arabidopsis Grown in Culture Is Regulated by Sucrose Uptake in the Aerial Tissues
Root System Architecture in Arabidopsis Grown in Culture Is Regulated by Sucrose Uptake in the Aerial Tissues
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DOI：
10.1105/tpc.107.055475
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发表时间：
2008-10-01
期刊：
影响因子：
11.6
通讯作者：
Malamy, Jocelyn E.
中科院分区：
文献类型：
--
作者：
MacGregor, Dana R.;Deak, Karen I.;Malamy, Jocelyn E.
本文提出了一个详细的模式，在培养拟南芥幼苗侧根形成的调控。我们表明，气生组织和蔗糖在生长介质中的直接接触是必要的，足以促进侧根原基从主根出现。根感受到轻度渗透胁迫，然后发出脱落酸依赖性信号，导致气生组织渗透性降低;这减少了从培养基中吸收蔗糖，导致侧根形成受到抑制。在培养中侧根形成的渗透抑制可以通过突变来克服，突变导致植物气生组织的角质层变得更具渗透性。事实上，我们在这里报告，先前描述的侧根发育2突变体克服侧根形成的渗透抑制，因为在长链酰基辅酶A合成酶2，角质生物合成所必需的基因的点突变。总之，我们的研究结果（1）影响了使用培养的拟南芥研究根系结构的实验的解释;（2）确定蔗糖作为侧根形成的意外调节剂;（3）证明了根将信息传递给气生组织并反过来接收信息的机制;以及（4）提供了对调控途径的深入了解，这些调控途径允许植物在发育过程中具有可塑性，同时保持地上和地下器官之间的基本平衡。
This article presents a detailed model for the regulation of lateral root formation in Arabidopsis thaliana seedlings grown in culture. We demonstrate that direct contact between the aerial tissues and sucrose in the growth media is necessary and sufficient to promote emergence of lateral root primordia from the parent root. Mild osmotic stress is perceived by the root, which then sends an abscisic acid-dependent signal that causes a decrease in the permeability of aerial tissues; this reduces uptake of sucrose from the culture media, which leads to a repression of lateral root formation. Osmotic repression of lateral root formation in culture can be overcome by mutations that cause the cuticle of a plant's aerial tissues to become more permeable. Indeed, we report here that the previously described lateral root development2 mutant overcomes osmotic repression of lateral root formation because of a point mutation in Long Chain Acyl-CoA Synthetase2, a gene essential for cutin biosynthesis. Together, our findings (1) impact the interpretation of experiments that use Arabidopsis grown in culture to study root system architecture; (2) identify sucrose as an unexpected regulator of lateral root formation; (3) demonstrate mechanisms by which roots communicate information to aerial tissues and receive information in turn; and (4) provide insights into the regulatory pathways that allow plants to be developmentally plastic while preserving the essential balance between aboveground and belowground organs.