微生物菌剂对绞股蓝药效成分及根际细菌群落的影响

Effects of microbial agents on the active constituents and rhizosphere bacterial community of Gynostemma pentaphyllum

摘要:

【目的】为缓解中药绞股蓝种植区由于连作导致的土壤微生态失衡，提高绞股蓝品质及产量，使用本课题组的娄彻氏链霉菌(Streptomyces rochei) D74菌剂及新构建的复合菌剂T3，研究微生物菌剂的施加对绞股蓝产量、品质以及根际细菌群落组成的影响，明确绞股蓝在连作和正茬不同种植条件下的适用菌剂。【方法】采用五点取样法，测定大田种植试验中各处理组绞股蓝单位面积的产量。采用紫外-可见分光光度法及高效液相色谱法测定黄酮、多糖、皂苷等绞股蓝主要药效成分含量。利用16S rRNA基因高通量测序技术分析添加菌剂对绞股蓝根际细菌群落结构的影响。【结果】在正茬型Z区地块，T3菌剂处理组绞股蓝干重较对照组增加了63.44%，总黄酮含量提高12.50%，总多糖含量提高32.95%，增产提质效果均优于D74菌剂；而在连作型P区地块，D74菌剂处理组绞股蓝干重较对照组增加了77.41%，总黄酮含量提高112.50%，总多糖含量提高23.10%，效果优于T3菌剂。通过分析微生物群落组间差异发现，与对照组相比富集在T3菌剂组中的差异微生物为新鞘氨醇菌属(Novosphingobium)、罗河杆菌属(Rhodanobacter) 等有益微生物，富集在D74菌剂组中的差异微生物为慢生根瘤菌属(Bradyrhizobium)、硝化螺菌属(Nitrospira)等有益微生物。【结论】研究表明T3复合菌剂及D74菌剂均能够通过招募土壤中有益微生物类群，优化根际土壤中微生物群落结构，改善绞股蓝根际微生态环境，显著提高绞股蓝药效成分含量及产量。D74菌剂在连作型地块施用效果更佳，T3菌剂对正茬型地块施用效果更佳。

Abstract:

[Objective] To alleviate the soil microecological imbalance caused by continuous cropping and improve the quality and yield of Gynostemma pentaphyllum, we studied the effects of Streptomyces rochei D74 and the newly developed compound microbial agent T3 on the yield, quality, and rhizosphere bacterial community composition of G. pentaphyllum, aiming to determine the suitable microbial agent for this medicinal plant in continuous cropping and rotational cropping. [Methods] The five-point sampling method was used to determine the yield of G. pentaphyllum per unit area in the field. The content of main active constituents including flavonoids, polysaccharides, and saponins was determined by UV-VIS spectrophotometry and high performance liquid chromatography. The 16S rRNA gene high-throughput sequencing was employed to reveal the rhizosphere bacterial community structure of G. pentaphyllum. [Results] In the Z-zone of rotational cropping, the dry weight, total flavonoids, and total polysaccharides of the T3 group increased by 63.44%, 12.50%, and 32.90%, respectively, compared with those in the control group, and T3 outperformed D74 in improving the yield and quality. In the P-zone of continuous cropping, the dry weight, total flavonoids, and total polysaccharides of the D74 group increased by 77.41%, 112.50%, and 23.10%, respectively, compared with those in the control group, and D74 outperformed T3. The differential microorganisms enriched in the T3 group compared with the control group were beneficial microorganisms such as Novosphingobium and Rhodanbacter, and those enriched in the D74 group were Bradyrhizobium and Nitrospira. [Conclusion] Both T3 and D74 could optimize the microbial community structure in rhizosphere soil and improve the micro-environment for plant growth by recruiting beneficial microorganisms in the soil, thus increasing the content and yield of the active constituents of G. pentaphyllum. D74 and T3 demonstrate better performance in the fields of continuous cropping and rotational cropping, respectively.