多组学解析氯化镧对胶红酵母合成类胡萝卜素的调节效应

Multi-omics analysis of hormesis effect of lanthanum chloride on carotenoid synthesis in Rhodotorula mucilaginosa

摘要:

在稀土元素的诱导下微生物的次级代谢产物合成可发生调节效应(hormesis effect)，但其分子机制仍不明确。为了解析胶红酵母在氯化镧存在下调节效应的分子机理，本研究在胶红酵母发酵培养基中添加不同浓度的氯化镧并测定类胡萝卜素含量，发现出现调节效应时La³⁺促进和抑制效应浓度分别为0–100 mg/L、100–400 mg/L；在促进效应浓度下，有33个基因表达量及55个代谢物合成量上调，85个基因的表达量及123个代谢物合成量下调，其中类胡萝卜素合成相关基因除AL1外均表达上调，β-胡萝卜素、番茄红素、虾青素含量分别提高了10.74%、5.02%、3.22%；在抑制效应浓度下，有5个基因表达量及91个代谢物合成量上调，35个基因的表达量及138个代谢物合成量下调，β-胡萝卜素、番茄红素、虾青素含量分别下降了21.73%、34.81%、35.51%。表明适宜浓度的稀土离子可以通过调节代谢途径的多种酶的酶活来调控次级代谢产物的合成进而产生调节效应。本研究不仅增进了对稀土元素在生物体内作用机制的理解，而且为稀土元素在农业、制药、医疗保健等领域的应用奠定了理论基础。

Abstract:

Hormesis effect has been observed in the secondary metabolite synthesis of microorganisms induced by rare earth elements. However, the underlying molecular mechanism remains unclear. To analyze the molecular mechanism of the regulatory effect of Rhodotorula mucilaginosa in the presence of lanthanum chloride, different concentrations of lanthanum chloride were added to the fermentation medium of Rhodotorula mucilaginosa, and the carotenoid content was subsequently measured. It was found that the concentrations of La³⁺ exerting the promotional and inhibitory effects were 0–100 mg/L and 100–400 mg/L, respectively. Furthermore, the expression of 33 genes and the synthesis of 55 metabolites were observed to be up-regulated, while the expression of 85 genes and the synthesis of 123 metabolites were found to be down-regulated at the concentration range of the promotional effect. Notably, the expression of carotenoid synthesis-related genes except AL1 was up-regulated. Additionally, the content of β-carotene, lycopene, and astaxanthin demonstrated increases of 10.74%, 5.02%, and 3.22%, respectively. The expression of 5 genes and the synthesis of 91 metabolites were up-regulated, while the expression of 35 genes and the synthesis of 138 metabolites were down-regulated at the concentration range of the inhibitory effect. Meanwhile, the content of β-carotene, lycopene, and astaxanthin decreased by 21.73%, 34.81%, and 35.51%, respectively. In summary, appropriate concentrations of rare earth ions can regulate the synthesis of secondary metabolites by modulating the activities of various enzymes involved in metabolic pathways, thereby exerting the hormesis effect. The findings of this study not only contribute to our comprehension for the mechanism of rare earth elements in organisms but also offer a promising avenue for the utilization of rare earth elements in diverse fields, including agriculture, pharmaceuticals, and healthcare.