除草剂对烤烟根际土壤微生物群落特征的影响

    Effects of herbicides on soil microbial community characteristics in tobacco fields

    • 摘要: 本研究采用高通量测序技术,系统解析了苯磺隆、烟嘧磺隆、二氯喹啉酸及氟磺胺草醚4种除草剂对烤烟根际土壤微生物群落与功能的动态影响。结果表明:除草剂处理显著改变了土壤真菌群落α多样性,均呈现先升高后下降的趋势,而细菌群落α多样性则保持相对稳定。非度量多维尺度分析表明,不同处理及不同采样时间(药后30和 60 d)的微生物β多样性均存在显著差异(P < 0.01),且真菌群落均与对照显著分离。随时间延长细菌优势类群由酸杆菌门(Acidobacteria)向放线菌门(Actinobacteria)演替,其中氟磺胺草醚处理对有益芽孢杆菌(Bacillus)的抑制作用最强(降幅达48.29%),而二氯喹啉酸的抑制作用最弱(11.83%);真菌群落则普遍呈现“病原菌(如青霉属(Penicillium))增殖、有益菌(如被孢霉属(Aspergillus))衰减”的趋势。除草剂处理均导致细菌群落的稀有类群和条件稀有类群减少。功能预测显示,除草剂处理普遍增强了细菌固氮功能但抑制了硝酸盐呼吸,并推动真菌群落向腐生-病原复合型演变。共现网络分析进一步揭示,不同除草剂驱动了特异的微生物适应策略:烟嘧磺隆富集耐酸固氮菌群,氟磺胺草醚筛选抗逆结构类群,苯磺隆激活高效降解网络,二氯喹啉酸塑造耐受多重胁迫的复杂群落。综上,4种除草剂显著改变了土壤微生物的结构与功能,增加了有益菌衰减与病原菌富集的潜在风险。

       

      Abstract: This study systematically analyzed the dynamic effects of four herbicides (tribenuron-methyl, nicosulfuron, quinclorac, and fomesafen) on the community, diversity, and metabolic function of the microbial community in the rhizosphere soil of flue-cured tobacco through high-throughput sequencing technology. The results showed that: Herbicide treatment significantly changed the alpha diversity of fungal communities, with a trend of first increasing and then decreasing, while bacterial alpha diversity remained relatively stable. Non-metric multidimensional scaling analysis showed significant differences (P < 0.01) in microbial beta diversity among different treatments and sampling times (30 d vs 60 d), and fungal communities were significantly separated from the control group. The dominant bacterial groups evolved from Acidobacteria to Actinobacteria. Among them, sulfonamide had the strongest inhibition on beneficial Bacillus (a decrease of 48.29%), while chloroquine had the weakest inhibition (11.83%). The fungal community generally exhibits a pattern of "proliferation of pathogenic bacteria (Penicillium) and decline of beneficial bacteria (Aspergillus)". All the herbicide treatments resulted in a decrease in rare and conditionally rare bacterial communities. Functional predictions show that herbicide treatment generally enhances bacterial nitrogen fixation but inhibits nitrate respiration and promotes the evolution of fungal communities towards a saprophytic pathogen complex. Co-occurring network analysis further revealed that different herbicides drive specific microbial adaptation strategies: nicotinuron enriches acid-resistant and nitrogen-fixing bacterial communities; sulfonamide selects for stress-resistant structural groups and activates efficient degradation networks; and chloroquine shapes complex communities tolerant to multiple stresses. In summary, the four herbicides significantly alter the structure and function of soil microorganisms, increasing the potential risk of beneficial bacteria decay and pathogen enrichment.

       

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