Response of soil microbial community diversity to continuous cucumber cropping in facilities along the Yellow River irrigation area

Temporal dynamics of soil microbial symbioses in the root zone of wolfberry: deciphering the effects of biotic and abiotic factors on bacterial and fungal ecological networks

Long-term monoculture of Lycium barbarum significantly affects its productivity and soil health. Soil microbiota, which mediate the sustainable development of soil ecosystems, are influenced by the age of wolfberry plants. However, the comprehensive effects of long-term cultivation of L. barbarum on the soil microbial community are not yet fully understood. Here, we assessed the effects of stand age on the diversity, composition, assembly, and symbiotic networks of bacterial and fungal communities in the root zone soil of L. barbarum using high-throughput sequencing technology. The results showed that stand age significantly affected the α-diversity of bacterial and fungal communities, as evidenced by the tendency of their Shannon and Chao1 indices to increase and then decrease. At the same time, the structure of soil bacterial and fungal communities was significantly influenced by tree age. However, Proteobacteria (28.77%-32.81%) was always the most dominant bacterial phylum, and Ascomycetes (49.72%-55.82%) was always the most dominant fungal phylum. A number of genus-level biomarkers were also identified in soils associated with roots of trees of varying ages. Additionally, stochastic processes dominated the assembly of soil bacterial communities, whereas the balance between stochastic and deterministic processes in the assembly of fungal communities fluctuated with stand age. The complexity and stability of bacterial and fungal community networks were notably affected by tree age, particularly in networks from 10- and 15-year-old trees. The partial least squares path modeling (PLS-PM) analysis emphasized that stand age can indirectly regulate the diversity and network complexity of both bacterial and fungal communities by influencing soil physicochemical properties. Furthermore, the bacterial community, but not the fungal community, exhibited direct and strong regulation of network complexity. The study offers valuable data for improving the soil quality and fruit yield of L. barbarum under long-term continuous cropping, which has implications for the sustainable development of the L. barbarum industry.

Continuous cropping of Patchouli alters soil physiochemical properties and rhizosphere microecology revealed by metagenomic sequencing

Continuous cropping (CC) profoundly impacts soil ecosystems, including changes in soil factors and the structure and stability of microbial communities. These factors are interrelated and together affect soil health and plant growth. In this research, metagenomic sequencing was used to explore the effects of CC on physicochemical properties, enzyme activities, microbial community composition, and functional genes of the rhizosphere soil of patchouli. We found that this can lead to changes in various soil factors, including the continuous reduction of pH andNH 4 + -N and the unstable changes of many factors. In addition, S-PPO enzyme activity increased significantly with the cropping years, but S-NAG increased in the first 2 years and decreased in the third cropping year. Metagenomic sequencing results showed that CC significantly changed the diversity and composition of rhizosphere microbial communities. The relative abundance of Pseudomonas and Bacteroides decreased substantially from the phylum level. At the genus level, the number of microbial genera specific to the zero-year cropping (CK) and first (T1), second (T2), and third (T3) years decreased significantly, to 1798, 172, 42, and 44, respectively. The abundance of many functional genes changed, among which COG0823, a gene with the cellular process and signaling functions, significantly increased after CC. In addition,NH 4 + -N, S-CAT, S-LAP, and SOC were the main environmental factors affecting rhizosphere-dominant microbial communities at the phylum level, while pH, SOC, and AK were the key environmental factors affecting rhizosphere functional genes of Pogostemon cablin. In summary, this study showed the dynamic changes of soil factors and rhizosphere microorganisms during CC, providing a theoretical basis for understanding the formation mechanism and prevention of CC obstacles and contributing to the formulation of scientific soil management and fertilization strategies.

Diallyl Trisulfide Acts as a Soil Disinfestation Against the Ilyonectria destructans through Inducing the Burst of Reactive Oxygen Species

Soil-borne diseases represent an impediment to the sustainable development of agriculture. A soil-borne disease caused by Ilyonectria destructans severely impacts Panax species, and soil disinfestation has proven to be an effective management approach. Here, diallyl trisulfide (DATS), derived from garlic, exhibited pronounced inhibitory effects on the growth of I. destructans in vitro tests and contributed to the alleviation of soil-borne diseases in the field. A comprehensive analysis demonstrated that DATS inhibits the growth of I. destructans by activating detoxifying enzymes, such as GSTs, disrupting the equilibrium of redox reactions. A series of antioxidant amino acids were suppressed by DATS. Particularly noteworthy is the substantial depletion of glutathione by DATS, resulting in the accumulation of ROS, ultimately culminating in the inhibition of I. destructans growth. Briefly, DATS could effectively suppress soil-borne diseases by inhibiting pathogen growth through the activation of ROS, and it holds promise as a potential environmentally friendly soil disinfestation.

Tetracycline removal from soil by phosphate-modified biochar: Performance and bacterial community evolution

Since the remediation performance of soil tetracycline pollution by original biochar is not ideal, many modified methods have been proposed to improve its performance. Considering the cost, complex modification process and environmental friendliness, many modified biochar are difficult to be used in soil environments. In this work, biochar derived from corn stover was modified using phosphate to increase the adsorption ability of soil tetracycline and alleviate the negative effects caused by tetracycline. The results showed that pyrolysis temperatures and anion types of phosphate (PO43-, HPO42-, H2PO4-) played important roles in the performance of modified biochar. Compared with original biochar, phosphate modified biochar not only improved the adsorption capacity, but also changed the adsorption behavior of tetracycline. Via SEM, BET and FTIR techniques, the intrinsic reasons for the increase of adsorption capacity were explained by the change of morphological structures as well as functional groups of the modified biochar. K3PO4 and high temperature (800 °C) maximally improved the surface morphology, increased the pore structure, changed the surface functional groups of biochar, and then increased the adsorption capacity of tetracycline (124.51 mg/g). Subsequently, the optimal material (K3PO4-800) was selected and applied for tetracycline contaminated soil remediation. Compared to the soil without remediation, K3PO4-800 modified biochar effectively reduced the effective concentration of tetracycline in soil, and improved soil K and P nutrition, and reshaped microbial communities. Our study showed that K3PO4-800 modified biochar was not only a good tetracycline resistant material, but also a good soil amendment.