Effects of Oxathiapiprolin on the Structure, Diversity and Function of Soil Fungal Community

Effects of root-irrigation with metalaxyl-M and hymexazol on soil physical and chemical properties, enzyme activity, and the fungal diversity, community structure and function

Fungicides are commonly applied through root irrigation in tobacco fields to control soil-borne diseases, and they affect soil microorganisms. However, the effects of metalaxyl-M and hymexazol, used to manage tobacco black shank disease, on these soil microecology remain poorly understood. This study employed high-throughput sequencing technology to explore the soil physical and chemical properties, soil enzyme activity, and the diversity, community structure and function of soil fungi in tobacco fields following root irrigation with metalaxyl-M and hymexazol. The results revealed that ammonium nitrogen (NH4+-N), nitrate nitrogen (NO3--N), soil organic matter (SOM), electrical conductivity (EC) and soil urease (UE) in soil were significantly increased and the pH decreased after root-irrigation with these two fungicides. The abundance of soil fungal community was significantly reduced after the root-irrigation of metalaxyl-M and hymexazol. The relative abundance of Ascomycota increased significantly after the treatment with metalaxyl-M. Following hymexazol treatment, the abundance of Achroiostachys, Nigrospora, Ustilaginoidea, and Trichoderma significantly decreased. Functional prediction analysis indicated an increase in the relative abundance of functional genes of saprophytic fungi after treatment with both fungicides. This study provides a foundational understanding of the environmental behavior and supports the scientific and rational use of metalaxyl-M and hymexazol in soil.

Forest Type and Climate Outweigh Soil Bank in Shaping Dynamic Changes in Macrofungal Diversity in the Ancient Tree Park of Northeast China

The community structure of macrofungi is influenced by multiple complex factors, including climate, soil, vegetation, and human activities, making it challenging to discern their individual contributions. To investigate the dynamic changes in macrofungal diversity in an Ancient Tree Park located in Northeast China and explore the factors influencing this change, we collected 1007 macrofungi specimens from different habitats within the park and identified 210 distinct fungal species using morphological characteristics and ITS sequencing. The species were classified into 2 phyla, 6 classes, 18 orders, 55 families, and 94 genera. We found macrofungal compositions among different forest types, with the mixed forest displaying the highest richness and diversity. Climatic factors, particularly rainfall and temperature, positively influenced macrofungal species richness and abundance. Additionally, by analyzing the soil fungal community structure and comparing aboveground macrofungi with soil fungi in this small-scale survey, we found that the soil fungal bank is not the main factor leading to changes in the macrofungal community structure, as compared to the influence of climate factors and forest types. Our findings provide valuable insights into the dynamic nature of macrofungal diversity in the Ancient Tree Park, highlighting the influence of climate and forest type.

Fungal network composition and stability in two soils impacted by trifluralin

Introduction

The composition and stability of soil fungal network are important for soil function, but the effect of trifluralin on network complexity and stability is not well understood.

Methods

In this study, two agricultural soils were used to test the impact of trifluralin on a fungal network. The two soils were treated with trifluralin (0, 0.84, 8.4, and 84 mg kg^-1) and kept in artificial weather boxes.

Results and discussion

Under the impact of trifluralin, the fungal network nodes, edges, and average degrees were increased by 6-45, 134-392, and 0.169-1.468 in the two soils, respectively; however, the average path length was decreased by 0.304-0.70 in both soils. The keystone nodes were also changed in trifluralin treatments in the two soils. In the two soils, trifluralin treatments shared 219-285 nodes and 16-27 links with control treatments, and the network dissimilarity was 0.98-0.99. These results indicated that fungal network composition was significantly influenced. After trifluralin treatment, fungal network stability was increased. Specifically, the network robustness was increased by trifluralin with 0.002-0.009, and vulnerability was decreased by trifluralin with 0.0001-0.00032 in the two soils. Fungal network community functions were also impacted by trifluralin in both soils. Trifluralin significantly impacts the fungal network.

Clomazone impact on fungal network complexity and stability

Introduction

Soil fungal network composition and stability are important for soil functions, but there is less understanding of the impact of clomazone on network complexity and stability.

Methods

In this work, two agricultural soils were used to investigate the impact of clomazone on fungal network complexity, composition, and stability. The two soils were treated with clomazone solution (0, 0.8, 8, and 80  mg kg^-1) and kept in an incubator.

Results and Discussion

Under the influence of clomazone, the fungal network nodes were decreased by 12-42; however, the average degree was increased by 0.169-1.468 and fungal network density was increased by 0.003-0.054. The keystone nodes were significantly changed after clomazone treatment. Network composition was also impacted. Specifically, compared with control and clomazone treatments in both soils, the shared edges were fewer than 54 in all comparisons, and network dissimilarity was 0.97-0.98. These results suggested that fungal network composition was significantly impacted. The network robustness was increased by 0.0018-0.0209, and vulnerability was decreased by 0.00018-0.00059 in both soils, which indicated that fungal network stability was increased by clomazone. In addition, the functions of network communities were also changed in both soils. These results indicated that clomazone could significantly impact soil fungal networks.