Biochemical responses and dynamics of the taxol biosynthesis pathway genes in Taxus baccata L. plants sprayed with melatonin under drought stress

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.

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.

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.

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.