保护性耕作增强了真菌群落生态网络稳定性

Conservation tillage enhanced the stability of fungal community network

摘要:

【目的】解析不同耕作措施下的土壤真菌群落组成以及病原真菌生态网络特征，为了解真菌在维持和改善农业生态系统稳定性方面提供科学依据。【方法】通过高通量测序技术，对传统犁耕(moldboard plow, MP)和保护性耕作[少耕(reduced tillage, RT)、免耕(no-tillage, NT)]下根际和非根际土壤中真菌群落的组成、多样性和真菌病原菌的关联网络特征进行了综合分析。【结果】与NT对比，MP和RT显著增加了土壤全碳(total carbon, TC)、全氮(total nitrogen, TN)和速效钾(available potassium, AK)的含量。根际效应对真菌群落的影响显著高于耕作措施。根际土壤中，RT处理的Shannon指数显著高于MP和NT。NT和RT处理显著降低了根际土壤中镰孢菌(Fusarium)和链格孢菌(Alternaria)的相对丰度。此外，RT降低了病原真菌的网络复杂性、减少了病原菌与其他真菌间的交互作用，增强了网络稳定性。【结论】保护性耕作RT是具有增加土壤养分、提升真菌网络稳定性且具有减轻病原菌有效传播作用的最佳耕作模式，为东北地区的耕作应用提供了新的视角。

关键词:保护性耕作;土壤微生物;微生物群落结构;病原真菌

Abstract:

[Objective] This study analyzed the fungal community composition and the pathogenic fungal network characteristics in the fields with different tillage measures, aiming to provide a scientific basis for understanding the role of microorganisms in maintaining and improving agroecosystem stability. [Methods] We employed high-throughput sequencing to investigate the composition and diversity of fungal communities and the network of fungal pathogens in the rhizosphere and bulk soils under the moldboard plow tillage (MP) and conservation tillage (reduced tillage: RT; no-tillage: NT). [Results] Compared with NT, MP and RT significantly increased the total carbon (TC), total nitrogen (TN), and available potassium (AK) in both the rhizosphere and bulk soils. The rhizosphere effect on the changes of fungal communities was greater than the effect of tillage measure. The Shannon index of the fungi in the rhizosphere soil under RT treatment was higher than that under MP and NT treatments. NT and RT decreased the relative abundance of Fusarium and Alternaria in the rhizosphere soils. In addition, RT reduced the network complexity of pathogenic fungi, weakened the interactions between the pathogenic fungi and their associated taxa, and enhanced the network stability. [Conclusion] These findings indicate RT as an optimal practice can increase soil nutrients, stabilize microbial network structure, and alleviate the potential transmission of pathogens, which provides a new perspective for tillage application in Northeast China.

Key words:conservation tillage;soil microorganisms;microbial community structure;pathogenic fungi