Cyclodipeptides (CDPs) are the smallest peptidic molecules that can be produced by diverse organisms such as bacteria, fungi, and animals. They have multiple biological effects. In this paper, we examined the CDPs produced by the bacteria Pseudomonas aeruginosa PAO1, which are known as opportunistic pathogens of humans and plants on TARGET OF RAPAMYCIN (TOR) signaling pathways, and regulation of root system architecture. This bacterium produces the bioactive CDPs: cyclo(L-Pro-L-Leu), cyclo(L-Pro-L-Phe), cyclo(L-Pro-L-Tyr), and cyclo(L-Pro-L-Val). In a previous report, these molecules were found to modulate basic cellular programs not only via auxin mechanisms but also by promoting the phosphorylation of the S6 ribosomal protein kinase (S6K), a downstream substrate of the TOR kinase. In the present work, we found that the inoculation of Arabidopsis plants with P. aeruginosa PAO1, the non-pathogenic P. aeruginosa ΔlasI/Δrhll strain (JM2), or by direct exposure of plants to CDPs influenced growth and promoted root branching depending upon the treatment imposed, while genetic evidence using Arabidopsis lines with enhanced or decreased TOR levels indicated a critical role of this pathway in the bacterial phytostimulation.

中文翻译：

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细菌环二肽促进拟南芥的生长涉及 TOR/S6K 通路激活

环二肽 (CDP) 是最小的肽分子，可由细菌、真菌和动物等多种生物产生。它们具有多种生物学效应。在本文中，我们研究了铜绿假单胞菌 PAO1 产生的 CDP，它是人类和植物在雷帕霉素靶标 (TOR) 信号通路上的机会性病原体，以及根系统结构的调节。这种细菌产生生物活性 CDP：环（L-Pro-L-Leu）、环（L-Pro-L-Phe）、环（L-Pro-L-Tyr）和环（L-Pro-L-Val） ）。在之前的一份报告中，发现这些分子不仅通过生长素机制，而且还通过促进 S6 核糖体蛋白激酶 (S6K)（TOR 激酶的下游底物）的磷酸化来调节基本细胞程序。在目前的工作中，