A Root-to-Shoot Signaling Pathway Controls Plant Development and Requires BYPASS1

植物的发育涉及到根和芽之间的协调，根负责探测水分和营养水平，芽负责植物的地上部分。然而，根源信号的性质以及它们如何控制茎的生长在很大程度上是未知的。最近对一种名为bypass1 （bps1）的拟南芥突变体的分析表明，在这种突变体中，根不断地产生一个信号，该信号在植物中传播，并能够阻止茎的生长。这一结果表明，BYPASS1 （BPS1）的功能是阻止可能通常用于控制植物生长的长距离信号的产生。西伯思实验室将开展旨在了解由BPS1控制的根到茎信号传导的实验。研究将使用遗传、生化和细胞生物学的方法来解决以下三个问题：(1)什么是移动信号；(2) BPS1与什么正常相互作用抑制信号产生；(3)信号是如何抑制嫩芽生长的？该实验有望确定信号产生所必需的类胡萝卜素的一个分支。这项工作还有望确定与BPS1相互作用的细胞蛋白：可能有助于指导植物产生信号或将环境信号传递给BPS1的蛋白质。最后，这项工作还有望确定如何控制芽的生长（例如，通过阻止细胞周期进展或抑制细胞扩增）。这项工作将为培养本科生、研究生和博士后提供从根到梢信号的深入研究。此外，从根到茎的信号被认为会大大降低农业生产率，尤其是在应对干旱时。对BPS1通路的深入了解可能为改变植物对根源信号的反应提供合理的基础，从而提高农业生产力。

Plant development involves coordination between roots, which detect water and nutrient levels and shoots, the above-ground portion of the plant. However, the nature of root-derived signals and how they work to control shoot growth is largely unknown. Recent analysis of an Arabidopsis mutant called bypass1 (bps1) showed that, in this mutant, the roots continually produced a signal that moved through the plant and was able to stop shoot growth. This result suggests that BYPASS1 (BPS1) functions to stop production of a long-distance signal that might normally be used to control plant growth. The Sieburth lab will carry out experiments directed toward understanding the root-to-shoot signaling controlled by BPS1. Research will use genetic, biochemical and cell biological approaches to address the following three questions: (1) what is the mobile signal; (2) what does BPS1 interact with normally that suppresses signal production; and (3) how does the signal inhibit shoot growth? The experiments are expected to identify a branch of the carotenoids that are required for signal production. The work is also expected to identify cellular proteins that interact with BPS1: proteins which might assist in directing the plant to generate the signal or function to transmit environmental signals to BPS1. Finally, the work is also expected to identify how shoot growth is controlled (e.g. by preventing cell cycle progression or by inhibiting cell expansion). This work will provide insight into root-to-shoot signaling while training undergraduate, graduate, and post-doctoral students. Moreover, root-to-shoot signals are believed to profoundly reduce agricultural productivity, especially in response to drought. Insight into the BPS1 pathway may provide a rational basis for engineering plants with altered responses to the root-derived signal, thus leading to boosts in agricultural productivity.