基于代谢组学探究金线莲对铅胁迫的响应机制

Response mechanism of Anoectochilus roxburghii (Wall.) Lindl. under lead stress based on metabonomics

  • 摘要: 【目的】通过分析铅胁迫后金线莲代谢产物变化,探讨金线莲对铅胁迫的响应机制。【方法】金线莲苗经铅胁迫处理后,于第0、7、14和30 d采样,测定全株金线莲黄酮、可溶性糖、游离氨基酸和金线莲苷等活性物质含量,分析铅胁迫对金线莲代谢产物的影响。【结果】随着铅胁迫时间的延长,芦丁和水仙苷2种黄酮及可溶性糖含量均呈现先增加后减少的变化趋势。在金线莲中检测出21种游离氨基酸,其中,天冬氨酸含量最高;脯氨酸(Pro)在胁迫后含量快速上升,并维持高位;其余游离氨基酸组分则直至第14 d后,开始出现显著上升(P<0.05)。非靶向代谢组学结果显示,第7、14和30 d差异代谢物数量分别为92、108和67,其中上调为6、32和10,下调为86、76和57,差异代谢物主要集中于脂肪酰基、氨基酸及其衍生物、异戊烯醇磷脂和有机酸类。存在极显著差异的代谢通路包括N-聚糖生物合成(上调),类胡萝卜素生物合成(上调),油菜素甾体生物合成,缬氨酸、亮氨酸和异亮氨酸降解,以及不饱和脂肪酸的生物合成。【结论】铅胁迫初期,金线莲可通过调节脂质代谢、氨基酸代谢及黄酮化合物的合成,从而减少胁迫损伤,但长期高含量铅胁迫会导致黄酮、氨基酸和金线莲苷等主要组分含量的下降。

     

    Abstract: 【Objective】 To analyze changes of metabolites of Anoectochilus roxburghii(Wall.) Lindl. after lead stress, to study response mechanism of A. roxburghii to lead stress.【Method】 After lead stress treatment, A. roxburghii seedlings were sampled at different time(0, 7, 14 and 30 d) to determine content of active substances such as flavonoids, soluble sugars, free amino acids, aureoside, and analyze effects of lead stress on A. roxburghii metabolites.【Result】 As lead stress went on, contents of 2 flavones(rutin and narcissin) and soluble sugar first increased and then decreased. 21 free amino acids were detected in A. roxburghii, and aspartic acid content was the highest;proline(Pro) content increased rapidly after stress and remained high;and components of other free amino acids started to increase significantly until 14 d (P<0.05). The results of non-targeted metabolomics showed that on the 7, 14 and 30 d, numbers of differential metabolites were 92, 108 and 67, respectively, of which 6, 32 and 10 were up-regulated and 86, 76, 57 were down-regulated. Differential metabolites were mainly fatty acyl, amino acids and their derivatives, prenol phospholipids and organic acids. Metabolic pathways with highly significant differences included N-glycan biosynthesis(up-regulated), carotenoid biosynthesis(up-regulated), brassinosteroid biosynthesis, valine, leucine and isoleucine degradation, and biosynthesis of saturated fatty acids.【Conclusion】 In the early lead stress, A. roxburghii can reduce stress damage by regulating lipid metabolism, amino acid metabolism and synthesis of flavonoid compounds, but long-term high-content lead stress will lead to the decrease of content of main component such as flavone, amino acid and kinsenoside.

     

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