Auxin plays a key role across all land plants in growth and developmental processes. Although auxin signaling function has diverged and expanded, differences in the molecular functions of signaling components have largely been characterized in Arabidopsis (Arabidopsis thaliana). Here, we used the nuclear Auxin Response Circuit recapitulated in yeast (Saccharomyces cerevisiae) (ARCSc) system to functionally annotate maize (Zea mays) auxin signaling components, focusing on genes expressed during development of ear and tassel inflorescences. All 16 maize auxin/indole-3-acetic acid (Aux/IAA) repressor proteins were degraded in response to auxin with rates that depended on both receptor and repressor identity. When fused to the maize TOPLESS (TPL) homolog RAMOSA1 ENHANCER LOCUS2 (REL2), maize Aux/IAAs were able to repress AUXIN RESPONSE FACTOR (ARF) transcriptional activity. A complete auxin response circuit comprising all maize components, including the ZmAFB2/3 b1 maize AUXIN SIGNALING F-BOX (AFB) receptor, was fully functional. The ZmAFB2/3 b1 auxin receptor was more sensitive to hormone than AtAFB2 and allowed for rapid circuit activation upon auxin addition. These results validate the conserved role of predicted auxin response genes in maize, as well as provide evidence that a synthetic approach can facilitate broader comparative studies across the wide range of species with sequenced genomes.

中文翻译：

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一种合成方法可以快速表征玉米核生长素响应回路。

生长素在所有陆地植物的生长和发育过程中都起着关键作用。尽管植物生长素的信号传导功能已发散和扩展，但在拟南芥（Arabidopsis thaliana）中已在很大程度上表征了信号传导成分的分子功能差异。在这里，我们使用了在酵母（Saccharomyces cerevisiae）（ARCSc）系统中概括的核生长素应答电路来功能性注释玉米（Zea mays）生长素信号转导成分，重点研究在穗和流苏花序发育过程中表达的基因。响应生长素，所有16种玉米生长素/吲哚-3-乙酸（Aux / IAA）阻遏蛋白均被降解，其速率取决于受体和阻遏物的特性。当与玉米TOPLESS（TPL）同系物RAMOSA1 ENHANCER LOCUS2（REL2）融合时，玉米Aux / IAA能够抑制AUXIN响应因子（ARF）的转录活性。包含所有玉米成分，包括ZmAFB2 / 3 b1玉米AUXIN SIGNALING F-BOX（AFB）受体的完整的生长素应答电路，功能完备。ZmAFB2 / 3 b1生长素受体比AtAFB2对激素更敏感，并允许在添加生长素后迅速激活电路。这些结果验证了预测的生长素反应基因在玉米中的保守作用，并提供了证据表明合成方法可以促进对具有测序基因组的广泛物种进行更广泛的比较研究。ZmAFB2 / 3 b1生长素受体比AtAFB2对激素更敏感，并允许在添加生长素后迅速激活电路。这些结果验证了预测的生长素反应基因在玉米中的保守作用，并提供了证据表明合成方法可以促进对具有测序基因组的广泛物种进行更广泛的比较研究。ZmAFB2 / 3 b1生长素受体比AtAFB2对激素更敏感，并允许在添加生长素后迅速激活电路。这些结果证实了预测的生长素反应基因在玉米中的保守作用，并提供了证据表明合成方法可以促进对具有序​​列基因组的广泛物种进行更广泛的比较研究。