彩色豆马勃对酸铝胁迫的代谢响应

Metabolic responses of Pisolithus tinctorius to acidic aluminum stress

摘要:

目的 分析酸铝胁迫下外生菌根真菌(ectomycorrhizal fungi, ECMF)细胞内、外的差异代谢物，揭示ECMF抗酸铝胁迫的关键代谢物及其代谢通路，从代谢生理角度完善ECMF抗铝机理，为将ECMF应用于铝毒危害林区的生态修复提供理论依据。方法 将彩色豆马勃(Pisolithus tinctorius)离体培养于含0.0 mmol/L和1.0 mmol/L Al³⁺的酸性(pH 3.8)培养基中，采用非靶向代谢组学分析其细胞内、外代谢物水平变化。结果 与0.0 mmol/L Al³⁺处理相比，1.0 mmol/L Al³⁺处理下P. tinctorius菌落直径显著降低23.67%。细胞内尿嘧啶核苷酸、胞苷磷酸、尿苷、尿苷二磷酸、胞苷和鸟苷等核苷酸上调；细胞外莽草酸、富马酸、庚酸和酒石酸等有机酸和l-阿拉伯糖、海藻糖、蔗糖和葡萄糖等糖类上调。嘧啶代谢和柠檬酸循环代谢通路在细胞内富集，ABC转运子和磷酸转移酶系统通路在细胞外富集。细胞内、外筛选到的潜在生物标志物分别为柠檬酸、海藻糖和酒石酸。结论 酸铝胁迫抑制P. tinctorius生长。在细胞内，P. tinctorius通过促进核苷酸积累和柠檬酸循环维持细胞稳态和能量供应；在细胞外，P. tinctorius通过促进有机酸分泌和糖类外排抵抗铝毒及其诱导的氧化损伤。

Abstract:

Objective By examining intracellular and extracellular metabolite changes in ectomycorrhizal fungi (ECMF) under acidic aluminum stress, we identified key resistance-related metabolites and pathways, aiming to elucidate the aluminum tolerance mechanisms from the perspective of metabolic physiology and offer a theoretical basis for using ECMF in restoring aluminum-contaminated forests.Methods Pisolithus tinctorius was cultured in vitro in the acidic medium (pH 3.8) containing 0.0 mmol/L or 1.0 mmol/L Al³⁺. Untargeted metabolomics was employed to analyze changes in intracellular and extracellular metabolite levels.Results Compared with that under the 0.0 mmol/L Al³⁺ treatment, the colony diameter of P. tinctorius under 1.0 mmol/L Al³⁺ stress decreased significantly by 23.67%. In addition, the intracellular levels of nucleotides including uridylic acid, cytidine monophosphate, uridine, uridine diphosphate, cytidine, and guanosine were upregulated under 1.0 mmol/L Al³⁺ stress. Extracellular levels of organic acids such as shikimic acid, fumaric acid, heptanoic acid, and tartaric acid, along with carbohydrates including l-arabinose, trehalose, sucrose, and glucose, were also upregulated. Pyrimidine metabolism and citric acid cycle pathways were enriched intracellularly, while ABC transporters and phosphotransferase system pathways were enriched extracellularly. The potential biomarkers identified in the intracellular environment was citric acid, and those identified in the extracellular environment were trehalose and tartaric acid.Conclusion Acidic aluminum stress inhibits the growth of P. tinctorius. Intracellularly, P. tinctorius maintains cellular homeostasis and energy supply through enhanced nucleotide accumulation and activation of the citric acid cycle. Extracellularly, P. tinctorius promotes organic acid secretion and carbohydrate efflux to resist aluminum toxicity and associated oxidative damage.