辣椒秸秆对滇黄精及其根际微生物群落的影响

Effects of hot pepper stalks on rhizosphere microflora structure of Polygonatum kingianum

摘要:

【背景】根际微生物直接或间接影响药用植物的生长发育和品质形成，通过改善土壤理化性质来提高益生菌多样性，促进植物病虫害的生物防治和提高植物产量、品质。【目的】探究栽培土壤中添加辣椒秸秆对滇黄精生长质量和根际细菌群落结构的影响。【方法】收集种植滇黄精无处理土壤(CK)、添加腐熟辣椒秸秆改良肥土壤(X)、添加商品复合肥土壤(Y)的根际附着土样，测量滇黄精生长质量，并通过高通量测序对其根际细菌群落进行功能和结构解析。【结果】X处理的滇黄精生长质量显著优于CK处理，而且与Y处理无显著差异，其中多糖含量和根系活力明显提高，分别较Y处理提高了24.48%和56.98%。同时显著增加了种植土壤的有机质和孔隙度。在根际细菌群落分析中，相对丰度最高的是变形菌门(Proteobacteria)，占比分别为CK的34.8%、X的34.6%、Y的41.3%，其中Y处理显著高于其他处理。其次是绿弯菌门(Chloroflexi)，X处理为10.2%，高于CK处理(8.7%)和Y处理(5.8%)。t检验中秸秆处理蓝细菌门Cyanobacteria丰度显著高于对照，芽单胞菌门(Gemmatimonadetes)和脱硫杆菌门(Desulfobacteria)显著高于化肥处理。三元相图(属水平)表明，CK处理中以Verrucomicrobium和Lysobacter丰度最高。X处理中以JG30-KF-AS9丰度最高。Y处理中是Pseudomonas和Mitochondria丰度最高。各处理间α多样性指数无显著差异。冗余分析表明，有机质和总孔隙度是影响秸秆处理细菌群落变化的主要驱动力，clusters of orthologous groups of proteins (COG)功能预测表明秸秆处理显著提高了COG功能数目，其特有COG数目为81，显著高于CK处理(3个)和Y处理(7个)。【结论】秸秆处理提高了滇黄精生长质量，改变了根际微生物群落，使相关有益微生物显著富集。这为特定环境因子下发掘新的功能类群微生物和有益微生物介导植物对环境的响应与微生物协同机制研究起到积极作用，同时也为生产中滇黄精优质栽培提供新的见解。

Abstract:

[Background] Rhizosphere microorganisms directly or indirectly affect the growth, development, and quality of medicinal plants. They improve the physical and chemical properties of soil to increase the diversity of probiotics, promote the biocontrol of plant diseases and insect pests, and improve the plant yield and quality. [Objective] To explore the effects of soil supplementation with hot pepper stalks on the growth quality and rhizosphere bacterial community structure of Polygonatum kingianum. [Methods] The rhizosphere soil samples of P. kingianum were collected from the control field (CK, without any treatment), the field fertilized with decomposed hot pepper stalks (X treatment), and the field fertilized with commercial compound fertilizer (Y treatment). The growth quality of P. kingianum was evaluated, and the bacterial community structure in rhizosphere soil was studied by high-throughput sequencing. [Results] The growth quality of P. kingianum in X treatment was significantly better than that in CK and had no significant difference from that in Y treatment. The polysaccharide content and root activity in X treatment were 24.48% and 56.98%, respectively, higher than those in Y treatment. In addition, the organic matter and soil porosity were also higher in X treatment than in Y treatment. In the rhizosphere bacterial community, Proteobacteria had the highest relative abundance, which was 34.8% in CK, 34.6% in X treatment, and 41.3% in Y treatment, and its relative abundance in Y treatment was significantly higher than that in other treatments. Chloroflexi had the second highest relative abundance, being higher in X treatment (10.2%) than in CK (8.7%) and Y treatment (5.8%). X treatment had significantly higher relative abundance of Cyanobacteria than CK and significantly higher relative abundance of Gemmatimonadetes and Desulfobacteria than Y treatment. The ternary phase diagram (at the genus level) indicated that the genera with the highest relative abundance were Verrucomicrobium and Lysobacter in CK, JG30-KF-AS9 in X treatment, and Pseudomonas and Mitochondria in Y treatment. The α diversity indexes showed no significant difference among treatments. The redundancy analysis showed that organic matter and total porosity were the main factors affecting the changes of bacterial community in X treatment. The cluster of orthologous group (COG) annotation showed that X treatment significantly increased the COGs, with the number of specific COGs (81) significantly higher than that of CK (3) and Y treatment (7). [Conclusion] X treatment improved the growth quality of P. kingianum, changed the structure of rhizosphere bacterial community, and enriched beneficial microorganisms. This study is conducive to the exploration of new functional groups of microorganisms and the research on microorganism-mediated plant response to the environment and microbial synergy under specific environmental conditions. Meanwhile, it gives new insights into the cultivation of P. kingianum.