Aims

This study aimed to assess the impact of exogenous melatonin on the expression of key genes in the taxol biosynthesis pathway (DBAT and TXS) and on taxol accumulation in Taxus baccata L. plants under different drought stress conditions. The research sought to determine how melatonin could modulate biochemical pathways to enhance plant resilience and secondary metabolite synthesis under stress.

Methods

The research was structured as a factorial experiment using a randomized complete design, with melatonin treatments at concentrations of 0, 100, 200, and 300 µM and drought stress levels corresponding to 100, 80, 60, and 40% field capacity. The primary endpoints analyzed were gene expression, taxol accumulation, plant growth parameters, and secondary metabolite production.

Results

The administration of 100 µM melatonin under mild drought conditions (80% FC) significantly enhanced the expression of the DBAT and TXS genes and resulted in the highest taxol production (1.93 mg g-1). Higher concentrations of melatonin (200 µM) were most effective in improving plant physiological traits including shoot and root biomass, height, and total chlorophyll content. Enhanced synthesis of phenolic and flavonoid compounds was particularly evident under moderate drought stress (60% FC) with melatonin treatments, underscoring an improved antioxidant capability.

Conclusions

Melatonin significantly improves drought resilience and stimulates the biosynthesis of taxol in Taxus baccata. These findings support the potential of melatonin in agricultural applications to boost plant growth, enhance stress tolerance, and increase the production of economically important secondary metabolites.

中文翻译：

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干旱胁迫下喷施褪黑素的红豆杉植株紫杉醇生物合成途径基因的生化反应及动态

 目标

本研究旨在评估外源褪黑素对不同干旱胁迫条件下红豆杉植物紫杉醇生物合成途径关键基因（ DBAT和TXS ）表达和紫杉醇积累的影响。该研究试图确定褪黑激素如何调节生化途径，以增强植物在胁迫下的恢复力和次生代谢物的合成。

 方法

该研究采用随机完整设计进行析因实验，褪黑激素处理浓度为 0、100、200 和 300 µM，干旱胁迫水平对应于 100、80、60 和 40% 田间持水量。分析的主要终点是基因表达、紫杉醇积累、植物生长参数和次生代谢产物产生。

 结果

在轻度干旱条件下（80% FC）施用 100 µM 褪黑素显着增强了DBAT和TXS基因的表达，并导致最高的紫杉醇产量（1.93 mg g-1）。较高浓度的褪黑激素（200 µM）对于改善植物生理性状（包括芽和根生物量、高度和总叶绿素含量）最有效。在中度干旱胁迫（60% FC）下，使用褪黑激素处理后，酚类和类黄酮化合物的合成增强尤其明显，这凸显了抗氧化能力的提高。

 结论

褪黑激素显着​​提高红豆杉的抗旱能力并刺激紫杉醇的生物合成。这些发现支持褪黑激素在农业应用中促进植物生长、增强抗逆性和增加经济上重要的次生代谢产物的产量的潜力。