Collaborative Research: Root-to-Shoot Communication via the bps Signal

干旱导致农业产量大幅度下降。 减轻干旱相关损失的一个重要步骤是充分了解干旱的感知如何导致增长放缓及其对农业生产的相关影响。 最早的干旱感知发生在根遇到干燥的土壤时，由此产生的整个植物的反应被认为是由一个移动的化学信号从根移动到芽。Sieburth实验室发现了一个高度保守的基因家族，该家族调节足以诱导干旱反应的根到芽信号的产生。 这项研究的目的是鉴定这种信号分子。 Sieburth和Dilkes实验室将使用基于代谢组学、遗传学和基因表达的方法。 这种策略的组合应该化学鉴定移动的信号，并建立其与根到芽信号传导的其他已知组分的关系。 了解根到茎信号的化学特性可以导致新的农业实践的发展，促进更大的粮食安全。植物干旱反应包括在芽中合成脱落酸（阿坝），并降低生长速度。 因为大多数干旱反应是在芽中测量的，而植物的根被认为是最初检测干旱条件的，科学家们长期以来一直假设一个移动的根到芽的化学信号来协调干旱反应。 拟南芥的bypass 1（bps 1）突变体具有由bps 1根中过度产生的嫁接传递信号引起的生长停滞表型。 转录组学和激素的测量表明，这种移动的化合物是足以诱导阿坝的合成在野生型芽，和遗传分析表明，生长停滞是独立的阿坝。 该项目的目标是对这种过度生产的化合物进行化学鉴定。实验将使用先前建立的提取方法，通过超高效液相色谱法进行分馏，并通过质谱进行分析。其他实验将使用标记的前体和前体类似物;这些将澄清活性产物中所需的前体结构组分，并且使用标记前体的时间分辨测定应证明其生物合成途径的信息。 此外，将比较bps 1和野生型根转录组，并进行反向遗传分析以测试差异表达的基因是否是产生移动的化合物所必需的。 最后，将在另一种植物物种中产生bps 1突变体，并分析其代谢物组;该实验将验证这种干旱诱导的根到茎化合物在不同植物物种中相同的假设。 不同的本科生和高中生将通过这个补助金进行培训;广泛的推广到代表性不足的群体，包括与当地社区学院的互动。这个奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Drought causes dramatic reductions in agricultural yields. An important step toward mitigating drought-associated losses is to fully understand how perception of drought causes reduced growth, and its associated impacts on agricultural production. The earliest perception of drought occurs as roots encounter dry soil, and the resulting whole-plant responses are believed to arise from a mobile chemical signal that moves from roots to shoots. The Sieburth lab has discovered a highly conserved gene family that regulates production of a root-to-shoot signal that is sufficient to induce drought responses. The goal of this research is to identify this signaling molecule. The Sieburth and Dilkes labs will use metabolomic, genetic, and gene expression based approaches. This combination of strategies should chemically identify the mobile signal and establish its relationship to other known components of root-to-shoot signaling. Knowing the chemical identity of the root-to-shoot signal could lead to development of new agricultural practices that promote greater food security.Plants drought responses include synthesis of abscisic acid (ABA) in the shoots, and decreased growth rates. Because most drought responses are measured in shoots, whereas the plant root is believed to initially detect drought conditions, scientists have long postulated a mobile root-to-shoot chemical signal that coordinates drought responses. The bypass1 (bps1) mutant of Arabidopsis has a growth-arrest phenotype caused by a graft-transmissible signal over-produced in bps1 roots. Transcriptomics and hormone measurements demonstrated that this mobile compound is sufficient to induce ABA synthesis in wild-type shoots, and genetic analyses demonstrated that growth arrest is independent of ABA. This project's goal is chemical identification of this over-produced compound. Experiments will use previously established extraction methods, fractionation by Ultra Performance Liquid Chromatography, and analysis by mass spec. Other experiments will use a labeled precursor and precursor analogs; these will clarify the structural components of the precursor that are required in the active product, and time-resolved assays using the labeled precursor should prove informative for its biosynthetic pathway. In addition, bps1 and wild type root transcriptomes will be compared, and reverse genetic analyses will be carried out to test whether differentially expressed genes are necessary to produce the mobile compound. Finally, bps1 mutants will be generated in another plant species, and its metabolome analyzed; this experiment will test the hypothesis that this drought-induced root-to-shoot compound is the same in different plant species. Diverse undergraduates and high-school students will be trained through this grant; broad outreach to under-represented groups includes interaction with local community colleges.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.