Herbicide glyphosate as a metabolic modulator of growth, carotenogenesis and lipogenesis in Dunaliella salina
摘要
The influence of the herbicide glyphosate on the metabolism of the green microalgae Dunaliella salina was studied. It is shown that glyphosate at a concentration of 350-1400 μg L-1 does not have a toxic effect on cells, but acts as a metabolic modulator and growth stimulator. Under the influence of the herbicide, cells maintain high photosynthetic and metabolic activity and a minimal level of oxidative stress. D. salina uses the organophosphorus herbicide as a nutrient source. The total increase in culture abundance in the control sample and at 350, 750, and 1400 μg L-1 of glyphosate was 32, 82, 128, and 111 %, respectively. The resistance of D. salina to the herbicide is probably explained by the presence of glyphosate-resistant forms of the shikimate pathway enzyme 5-enolpyruvylshikimate-3-phosphate synthase, which is the main target of its action. A significant increase in the total pool of fatty acids by 60 % at 1400 μg L-1 glyphosate has been established, primarily due to an increase in the content of palmitic, palmitoleic, oleic, and linoleic fatty acids. Specific redirection of metabolic fluxes under the influence of glyphosate has been revealed. Increasing glyphosate concentration leads to a 25% increase in lipid content in D. salina due to the synthesis of structural lipids. Additionally, glyphosate inhibits β-carotene synthesis, and the metabolic flux is redirected toward lutein synthesis. The results indicate the promising potential of using D. salina for biotechnological purposes, including the targeted production of lutein and polar lipids, as well as in bioremediation technologies for aquatic environments contaminated with residual amounts of glyphosate.