Deeper and longer roots allow crops to survive and flourish, but our understanding of the plant growth regulators promoting root system establishment is limited. Here, we report that, a novel auxin receptor agonist, named K-10, had a remarkable promotive effect on root growth in both Arabidopsis thaliana and Oryza sativa through the enhancement of root-related signaling responses. Using computer-aided drug discovery approaches, we developed potent lead compound by screening artificial chemicals on the basis of the auxin receptor TIR1 (Transport Inhibitor Response 1), and a series of N-(benzo[d] [1,3] dioxol-5-yl)-2-(one-benzylthio) acetamides, K-1 to K-22, were designed and synthesized. The results of bioassay showed that K-10 exhibited an excellent root growth-promoting activity far exceeding that of NAA (1-naphthylacetic acid). A further morphological investigation of the auxin related mutants (yucQ, tir1) revealed that K-10 had auxin-like physiological functions and was recognized by TIR1, and K-10 significantly enhanced auxin response reporter’s (DR5:GUS) transcriptional activity. Consistently, transcriptome analysis showed that K-10 induced a common transcriptional response with auxin and down-regulated the expression of root growth-inhibiting genes. Further molecular docking analysis revealed that K-10 had a stronger binding ability with TIR1 than NAA. These results indicated that this class of derivatives could be a promising scaffold for the discovery and development of novel auxin receptor agonists, and the employment of K-10 may be effective for enhancing root growth and crop production.

更深更长的根系使作物得以生存和繁茂，但我们对促进根系建立的植物生长调节剂的了解有限。在这里，我们报告说，一种名为 K-10 的新型生长素受体激动剂对两种植物的根系生长都有显着的促进作用。拟南芥和水稻通过增强与根相关的信号反应。使用计算机辅助药物发现方法，我们通过基于生长素受体 TIR1（转运抑制剂反应 1）和一系列 N-（苯并 [d] [1,3] 二氧设计和合成了 5-基）-2-（单苄硫基）乙酰胺，K-1 至 K-22。生物测定结果表明，K-10 具有远超 NAA（1-萘乙酸）的优良生根促进活性。生长素相关突变体的进一步形态学研究（优酷,提尔1(DR5:GUS) 转录活性。一致地，转录组分析表明，K-10 与生长素诱导共同的转录反应，并下调根生长抑制基因的表达。进一步的分子对接分析表明，K-10 与 TIR1 的结合能力比 NAA 更强。这些结果表明，这类衍生物可能是发现和开发新型生长素受体激动剂的有前景的支架，而 K-10 的使用可能对促进根系生长和作物产量有效。