不同产地桔梗皂苷生物合成与土壤元素关系的研究

Effects of soil elements on platycodin biosynthesis process in Platycodon grandiflorum from different habitats

目的 研究桔梗皂苷积累与土壤元素的关系,从基因表达水平明确不同产地桔梗皂苷含量差异的原因,为桔梗药材的科学种植提供理论依据。方法 利用HPLC法和香草醛-冰醋酸比色法测定不同产地桔梗韧皮部和木质部的桔梗皂苷D和桔梗总皂苷含量,实时荧光定量PCR测定6种关键酶基因的表达量,利用原子吸收法、比色法等方法测定土壤元素含量,用Pearson相关性分析法分析土壤元素与桔梗皂苷及其关键酶基因表达量的关系。结果 河南洛阳产桔梗根中的桔梗皂苷D和桔梗总皂苷含量显著高于其他产地,桔梗韧皮部和木质部的桔梗皂苷含量和关键酶基因表达量存在较大差异;相关性分析表明,土壤中Cu、Ca和Zn含量对桔梗皂苷的合成起主要作用,甲羟戊酸焦P酸脱羧酶基因、法尼基焦P酸合酶基因和异戊烯基焦P酸异构酶基因是桔梗皂苷合成过程中的主要关键酶基因,土壤元素对桔梗关键酶基因具有一定的调控作用。结论 土壤元素通过调控关键酶基因进而影响桔梗皂苷的合成,其中土壤中Zn含量起主要作用。

Objective To explore the relationship between platycodin accumulation and soil elements, to identify the reasons for the the content difference of Platycodon grandiflorum between different origins from the gene expression level, and to provide a theoretical basis for the scientific cultivation of P. grandiflorum. Methods The content of platycodin D and total platycodin in phloem and xylem from different habitats were determined by HPLC and vanilla aldehyde-glacial acetic acid colorimetric, the expression of key enzyme genes were determined by real-time quantitative PCR, the content of soil elements were determined by Atomic Absorption Method. And the relationship between soil elements and the expression levels of platycodin and its key enzyme genes was analyzed by Pearson correlation analysis. Results The content of platycodin D and total platycodin from Luoyang,Henan, was significantly higher than those of other habitats;Platycodin content and expression of key enzyme genes in phloem and xylem of P. grandiflorum were quite different;Contents of Cu, Ca and Zn in soil play a major role in the synthesis of platycodin,mevalonate pyrophosphate decarboxylase gene(MVD), farnesyl pyrophosphate synthase gene(FPPS) and isopentenyl diphosphate isomerase gene(IPPI) genes were the main key enzyme genes in the synthesis of platycodin;Soil elements had a certain regulatory effect on the expression of key enzyme genes. Conclusion Soil elements affect the synthesis of platycodin by regulating key enzyme genes, with Zn content in the soil playing a major role.