The fungal species Fusarium can cause devastating disease in agricultural crops. Phenamacril is an extremely specific cyanoacrylate fungicide and a strobilurine analog that has excellent efficacy against Fusarium. To date, information on the mechanisms involved in the uptake, accumulation, and metabolism of phenamacril in plants is scarce. In this study, lettuce and radish were chosen as model plants for a comparative analysis of the absorption, accumulation, and metabolic characteristics of phenamacril from a polluted environment. We determined the total amount of phenamacril in the plant-water system by measuring the concentrations in the solution and plant tissues at frequent intervals over the exposure period. Phenamacril was readily taken up by the plant roots with average root concentration factor ranges of 60.8–172.7 and 16.4–26.9 mL/g for lettuce and radish, respectively. However, it showed limited root-to-shoot translocation. The lettuce roots had a 2.8–12.4-fold higher phenamacril content than the shoots; whereas the radish plants demonstrated the opposite, with the shoots having 1.5 to 10.0 times more phenamacril than the roots. By the end of the exposure period, the mass losses from the plant-water systems reached 72.0% and 66.3% for phenamacril in lettuce and radish, respectively, suggesting evidence of phenamacril biotransformation. Further analysis confirmed that phenamacril was metabolized via hydroxylation, hydrolysis of esters, demethylation, and desaturation reactions, and formed multiple transformation products. This study furthers our understanding of the fate of phenamacril when it passes from the environment to plants and provides an important reference for its scientific use and risk assessment.

Fumonisin B1 (FB1) is a neurodegenerative mycotoxin synthesized by Fusarium spp., but the potential neurobehavioral toxicity effects in organisms have not been characterized clearly. Caenorhabditis elegans (C. elegans) has emerged as a promising model organism for neurotoxicological studies due to characteristics such as well-functioning nervous system and rich behavioral phenotypes. To investigate whether FB1 has neurobehavioral toxicity effects on C. elegans, the motor behavior, neuronal structure, neurotransmitter content, and gene expression related with neurotransmission of C. elegans were determined after exposed to 20–200 μg/mL FB1 for 24 h and 48 h, respectively. Results showed that FB1 caused behavioral defects, including body bends, head thrashes, crawling distance, mean speed, mean amplitude, mean wavelength, foraging behavior, and chemotaxis learning ability in a dose-, and time-dependent manner. In addition, when C. elegans was exposed to FB1 at a concentration of 200 μg/mL for 24 h and above 100 μg/mL for 48 h, the GABAergic and serotonergic neurons were damaged, but no effect on dopaminergic, glutamatergic, and cholinergic neurons. The relative content of GABA and serotonin decreased significantly. Furthermore, abnormal expression of mRNA levels associated with GABA and serotonin were found in nematodes treated with FB1, such as unc-30, unc-47, unc-49, exp-1, mod-5, cat-1, and tph-1. The neurobehavioral toxicity effect of FB1 may be mediated by abnormal neurotransmission of GABA and serotonin. This study provides useful information for understanding the neurotoxicity of FB1.

Heavy metal pollution in soil around abandoned mine sites is one of the most critical environmental issues worldwide. Soil microbes form complex communities and perform ecological functions individually or in cooperation with other organisms to adapt to harsh environments. In this study, we investigated the distribution patterns of bacterial and fungal communities in non-contaminated and heavy metal-contaminated soil of the abandoned Samkwang mine in Korea to explore microbial interaction mechanisms and their modular structures. As expected, the bacterial and fungal community structures showed large differences depending on the degree of heavy metal contamination. The microbial network was divided into three modules based on the levels of heavy metal pollution: heavy metal-tolerant (HM-Tol), heavy metal-mid-tolerant (HM-mTol), and heavy metal-sensitive (HM-Sens) modules. Taxonomically, microbes assigned to Vicinamibacterales, Pedosphaeraceae, Nitrosomonadaceae, and Gemmatimonadales were the major groups constituting the HM-Tol module. Among the detected heavy metals (As, Pb, Cd, Cu, and Zn), copper concentrations played a key role in the formation of the HM-Tol module. In addition, filamentous fungi (Fusarium and Mortierella) showed potential interactions with bacteria (Nitrosomonadaceae) that could contribute to module stability in heavy metal-contaminated areas. Overall, heavy metal contamination was accompanied by distinct microbial communities, which could participate in the bioremediation of heavy metals. Analysis of the microbial interactions among bacteria and fungi in the presence of heavy metals could provide fundamental information for developing bioremediation mechanisms for the recovery of heavy metal-contaminated soil.

Biofumigation is an effective, non-chemical method to control soil-borne pests and diseases and to maximize crop yield. We studied the responses of soil bacterial and fungal communities, the soil’s nutritional state and strawberry yield, when the soil was biofumigated each year for five consecutive years using fresh chicken manure (BioFum). BioFum significantly increased the soil’s NH4+-N, NO3−-N, available P and K and organic matter. Fusarium spp. and Phytophthora spp. which are known to cause plant disease, were significantly decreased after BioFum. In addition, Biofum increased the soil’s temperature, enhanced chlorophyll levels in the leaves of strawberry plants, and the soluble sugar and ascorbic acid content in strawberry fruit. We used high-throughput gene sequencing to monitor changes in the soil’s bacterial and fungal communities. Although BioFum significantly decreased the diversity of these communities, it increased the relative abundance of some biological control agents in the phylum Actinobacteria and the genera Pseudomonas, Bacillus and Chaetomium. An increase in these biological control agents would reduce the incidence of soil-borne pathogens and plant disease. Although strawberry marketable yield using BioFum was higher in the first three years, the decline in the final two years could be due to the accumulation of P and K which may have delayed flowering and fruiting. Methods to overcome yield losses using BioFum need to be developed in the future. Our research, however, showed that BioFum enhanced soil fertility, reduced the presence of soil pathogens, increased the relative abundance of beneficial bacteria and fungi and improved strawberry quality. Unlike chemical soil treatments that can cause pest and disease resistance when used continuously over many years, our multi-year research program on BioFum showed that this treatment provided significant benefits to the soil, plant and strawberry fruit.

Mycotoxins are toxic fungal metabolites, contaminating cereal grains in field or during processing and storage periods. These environmental contaminants pose great threats to humans and animals’ health due to their toxic effects. Type A trichothecenes, fumonisins and fusaric acid (FA) are commonly detected mycotoxins produced by various Fusarium species. Trichoderma spp. are promising antagonists in agriculture for their activities against plant pathogens, and also regarded as potential candidates for bioremediation of environmental contaminants. Managing toxigenic fungi by antagonistic Trichoderma is regarded as a sustainable and eco-friendly strategy for mycotoxin control. However, the metabolic activities of Trichoderma on natural occurring mycotoxins were less investigated. Our current work comprehensively explored the activities of Trichoderma against type A trichothecenes, fumonisins and FA producing Fusarium species via co-culture competition and indirect volatile assays. Furthermore, we investigated metabolism of type A trichothecenes and FA in Trichoderma isolates. Results indicated that Trichoderma were capable of bio-transforming T-2 toxin, HT-2 toxin, diacetoxyscirpenol and neosolaniol into their glycosylated forms and one Trichoderma strain could bio transform FA into low toxic fusarinol. These findings proved that Trichoderma isolates could manage toxigenic Fusarium via direct competition and volatile-mediated indirect inhibition. In addition, these antagonists possess defensive systems against mycotoxins for self-protection, which enriches our understanding on the interaction mechanism of Trichoderma spp. on toxigenic fungus.

Multiple sources of microplastics (MPs) in farmland could result in the changing of microbial community and the plant growth. Most studies of MPs in agricultural system have focused on the effects of single types of MPs on growth of plants, while neglect interactions between multiple types of MPs. In this study a pot-experiment was conducted to investigate the effects of multiple types of MPs, including polystyrene beads: M1, 5 μm, M2, 70 nm and degradable mulching film (DMF) fragments on growth of wheat seedlings and associated rhizosphere microbial community. CKD (adding DMF) significantly reduced plant height and base diameter of wheat seedlings. DMF in combination with M2, significantly increased plant height and aboveground biomass, but decreased the base diameter. Actinobacteria was the dominant taxa in the rhizosphere bacterial community in various treatments. PCoA analysis showed that the bacterial composition in M2HD (100 mg kg⁻¹ M² with DMF) was significantly different from that of CKD and M2LD (10 mg kg⁻¹ M² with DMF). At the level of genera, the dominant fungi in CKD and M2LD were in the genus Fusarium, which is the cause of wheat fusarium blight and Alternaria, which results in decreased base diameter. In CK (control group) and M2HD, Blastobotrys exhibited the greatest abundance, which assisted wheat seedlings in resisting Verticillium disease. Cluster and PCoA analysis showed the fungal composition in CKD was significantly different from CK, M2LD and M2HD. These findings suggest MPs potentially have selective effects on pathogens that affect growth of plants and potentially safety of the food.

Soil-borne diseases have become increasingly problematic for farmers producing crops intensively under protected agriculture. Although soil fumigants are convenient and effective for minimizing the impact of soil-borne disease, they are most often detrimental to beneficial soil microorganisms. Previous research showed that bio-activation of soil using biological control agents present in biofertilizers or organic fertilizers offered promise as a strategy for controlling soil-borne pathogens when the soil was bio-activated after fumigation. Our research sought to determine how bio-activation can selectively inhibit pathogens while promoting the recovery of beneficial microbes. We monitored changes in the soil’s physicochemical properties, its microbial community and reductions in soil-borne pathogens. We found that the population density of Fusarium and Phytophthora were significantly reduced and tomato yield was significantly increased when the soil was bio-activated. Soil pH and soil catalase activity were significantly increased, and the soil’s microbial community structure was changed, which may have enhanced the soil’s ability to reduce Fusarium and Phytophthora. Our results showed that soil microbial diversity and relative abundance of beneficial microorganisms (such as Sphingomonas, Bacillus, Mortierella and Trichoderma) increased shortly after bio-activation of the soil, and were significantly and positively correlated with pathogen suppression. The reduction in pathogens may have been due to a combination of fumigation-fertilizer that reduced pathogens directly, or the indirect effect of an optimized soil microbiome that improved the soil’s non-biological factors (such as soil pH, fertility structure), enhanced the soil’s functional properties and increased tomato yield.

Chloropicrin (CP) controls soil-borne plant diseases caused by pathogenic microbes, increases crop yield, but has a long-term inhibitory effect on beneficial soil microorganisms. Therefore, we evaluated the effects of biofumigation material fresh chicken manure (FCM) on soil microorganisms, and the duration of those effects in this experiment. Our results showed that in the laboratory, FCM significantly increased substrate-induced respiration (SIR) of soil microorganisms by 2.2–3.2 times at 80 d compared to the control, however, CP significantly inhibited the SIR of soil microorganisms. FCM and CP increased NH4+-N concentration within 40 days which then returned to the control level. FCM increased NO3--N by 2.82–5.78 times by 80 days, compared with the control, while the concentration of NO3--N in the CP treatment was not significantly different from the control at the 80 day. Although in the laboratory FCM inhibited the relative abundance of 16 S rRNA and the nitrogen cycle functional genes AOA amoA, AOB amoA, nirK and nosZ over a 40-day period, the taxonomic diversity of soil bacteria and fungi in the FCM treatment were restored to unfumigated level within 90 days in the field. However, CP treatment has a strong inhibitory effect on soil microorganisms after 90 days. Importantly, the relative abundance of some beneficial microorganisms that control soil-borne pathogenic microbes or degrade pollutants increased significantly in FCM, including Bacillus, Pseudomonas and Streptomyces bacterial genera and Chaetomium and Mycothermus fungal genera. Noteworthy, like CP, FCM still had a strong inhibitory effect on Fusarium at 90 d. Our results indicated that FCM not only increased the content of inorganic nitrogen and improved the respiration rate of soil microorganisms, but it also shortened the recovery time of beneficial soil microorganisms and increased taxonomic diversity. Our previous reports showed that FCM and CP treatments had the same effect in disease control and crop growth. Combined with the results of this experiment, we believe that FCM has the potential to replace CP, which would eliminate CP's detrimental environmental impact, improve farmer safety and promote sustainable crop production.

Particulate matter (PM) released from the processes of livestock production has a negative impact on the health of animals and workers. Herein, the concentration, major chemical components, morphology and microbiological compositions of particulate matter 2.5 (PM2.5, particles with aerodynamic diameter less than 2.5 μm) in a broiler breeding house were investigated. The results showed that the PM2.5 distribution in the chicken house was affected by the illumination, draught fans, chicken frame structure and activity of the chickens in the broiler breeding house. Component analysis showed that organic carbon (OC) accounted for the largest proportion, and followed by element carbon (EC), SO42−, NO3−, NH4+, Na+, K+ and Ca2+. Ultrastructural observations revealed that the shape of PM2.5 had a round, rectangular, chain-like and irregular shape. The concentration of endotoxin was approximately 0.3 EU/m3. Microbiological analysis showed that at the genus level, the pathogenic bacteria included Staphylococcus, Corynebacterium, Enterococcus, Parabacteroides, Escherichia and Megamonas. The abundant harmful fungi were Aspergillus, Scopulariopsis, Wallemia, and Fusarium. Through redundancy analysis (RDA) analysis, we determined that OC, EC, Na+, K+, and NH4+ had strong correlations with Brachybacterium, Brevibacterium, Corynebacterium, Escherichia, Scopulariopsis and Microascus. SO42− was closely related to Scopulariopsis and Salinicoccus. Salinicoccus was also strongly correlated with NO3−. Our results indicated that feed, faeces, and outside soot are contributed to the increase in PM2.5 concentration in the chicken house, while the sources of the dominant bacterial and fungi might be feed, faeces, suspended outside soil and cereal crops.

Soil fumigants aim to control soil-borne diseases below levels that affect economic crop production, but their use also reduces the abundance of beneficial microorganisms. Previous studies have shown that adding various types of fertilizers to soil after fumigation can reshape the soil microbial community and regulate crop growth. We fumigated soil with dazomet (DZ) that had been cropped continuously for more than 20 years. After fumigation we applied silicon fertilizer, potassium humate organic fertilizer, Bacillus microbial fertilizer or a mixture of the last two. We studied the effects of different fertilizers treatments on the soil's physicochemical properties, enzyme activities, key soil pathogens and beneficial microbes. We found that fertilizers applied after fumigation promoted soil beneficial microorganisms (such as Fimicutes, Chloroflexi, Bacillus and Actinomadura) restoration; increased Fusarium and Phytophthora pathogen mortality, the content of ammonium nitrogen, sucrase enzyme activity; and increased strawberry fruit yield. A significant increase in strawberry yield was positively correlated with increases in beneficial microorganisms such as Gemmatimonadota, Firmicutes, Bacillus and Flavisolibacter. We concluded that organic fertilizer applied after fumigation significantly increased the number of beneficial microorganisms, improved the physicochemical properties of the soil, increased soil enzyme activities, inhibited the growth of soil pathogens to increase strawberry fruit yield. In summary, organic fertilizer activated soil beneficial microorganisms after soil fumigation, promoted soil health, and increased strawberry fruit yield.