Methyl 3-(4-hydroxyphenyl)propionate (MHPP) is a root exudate that functions as a nitrification inhibitor and as a modulator of the root system architecture (RSA) by inhibiting primary root (PR) elongation and promoting lateral root formation. However, the mechanism underlying MHPP-mediated modulation of the RSA remains unclear. Here, we report that MHPP inhibits PR elongation in Arabidopsis (Arabidopsis thaliana) by elevating the levels of auxin expression and signaling. MHPP induces an increase in auxin levels by up-regulating auxin biosynthesis, altering the expression of auxin carriers, and promoting the degradation of the auxin/indole-3-acetic acid family of transcriptional repressors. We found that MHPP-induced nitric oxide (NO) production promoted reactive oxygen species (ROS) accumulation in root tips. Suppressing the accumulation of NO or ROS alleviated the inhibitory effect of MHPP on PR elongation by weakening auxin responses and perception and by affecting meristematic cell division potential. Genetic analysis supported the phenotype described above. Taken together, our results indicate that MHPP modulates RSA remodeling via the NO/ROS-mediated auxin response pathway in Arabidopsis. Our study also revealed that MHPP significantly induced the accumulation of glucosinolates in roots, suggesting the diverse functions of MHPP in modulating plant growth, development, and stress tolerance in plants.

中文翻译：

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硝化抑制剂 3-(4-羟基苯基)丙酸甲酯通过 NO/ROS 途径干扰生长素信号传导来调节根系发育。


3-(4-羟基苯基)丙酸甲酯 (MHPP) 是一种根分泌物，可作为硝化抑制剂和根系结构 (RSA) 调节剂，通过抑制初生根 (PR) 伸长和促进侧根形成。然而，MHPP 介导的 RSA 调节机制仍不清楚。在此，我们报告 MHPP 通过提高生长素表达和信号传导水平来抑制拟南芥 (Arabidopsis thaliana) 中的 PR 延伸。 MHPP 通过上调生长素生物合成、改变生长素载体的表达以及促进转录抑制因子生长素/吲哚-3-乙酸家族的降解来诱导生长素水平增加。我们发现 MHPP 诱导的一氧化氮 (NO) 产生促进了根尖活性氧 (ROS) 的积累。抑制 NO 或 ROS 的积累通过削弱生长素反应和感知以及影响分生细胞分裂潜力，减轻了 MHPP 对 PR 伸长的抑制作用。遗传分析支持上述表型。综上所述，我们的结果表明，MHPP 通过拟南芥中 NO/ROS 介导的生长素反应途径调节 RSA 重塑。我们的研究还表明，MHPP 显着诱导根部芥子油苷的积累，表明 MHPP 在调节植物生长、发育和植物胁迫耐受性方面具有多种功能。