Biocontrol agents applied after fumigation play an important role to the soil microenvironment. We studied the effect of Trichoderma applied after dimethyl disulfide (DMDS) plus chloropicrin (PIC) fumigation on the cucumber growth, soil physicochemical properties, enzyme activity, taxonomic diversity, and yield through laboratory and field experiments. The results confirmed that Trichoderma applied after fumigation significantly improved soil physicochemical properties, cucumber growth, soil-borne pathogens, and soil enzyme activity. Genetic analysis indicated that Trichoderma applied after fumigation significantly increased the relative abundance of Pseudomonas, Humicola and Chaetomium, and significantly decreased the relative abundance of the pathogens Fusarium spp. and Gibberella spp., which may help to control pathogens and enhanced the ecological functions of the soil. Moreover, Trichoderma applied after fumigation obviously improved cucumber yield (up to 35.6%), and increased relative efficacy of soil-borne pathogens (up to 99%) and root-knot nematodes (up to 96%). Especially, we found that Trichoderma applied after fumigation increased the relative abundance of some beneficial microorganisms (such as Sodiomyces and Rhizophlyctis) that can optimize soil microbiome. It is worth noting that with the decline in the impact of the fumigant, these beneficial microorganisms still maintain a higher abundance when the cucumber plants were uprooted. Importantly, we found one tested biocontrol agent Trichoderma 267 identified and stored in our laboratory not only improved cucumber growth, reduced soil-borne diseases in late cucumber growth stages but also optimized micro-ecological environment which may have good application prospect and help to keep environmental healthy and sustainable development.

Chloropicrin (CP) can cause long-term damage to beneficial microbes which reduces soil health. Biochar (BC) can mitigate against the effects of CP by reducing the time for beneficial microbes to recover after CP fumigation. In this study, we used Real-Time Quantitative PCR to determine the effects of different rates of BC added to CP-fumigated soil on the speed of recovery of bacteria and fungi population and on changes to gene copy number of the target pathogen Fusarium oxysporum. And then we compared the structure and composition of the beneficial microbial community in the different treatments soil by using High throughput Illumina sequencing. As the results shown, adding 1 or 3% BC after CP fumigation accelerated the recovery of bacterial and fungal populations without increasing F. oxysporum abundance. BC also promoted the recovery of beneficial bacteria Rokubacteria and Latescibacteria damaged by CP. And these two bacteria may be related to the immunity of soil to F. oxysporum. In CP-fumigated soil, BC improved the disease resistance of the soil by increasing beneficial microbes, such as Steroidobacter, Sphingomonas, Purpureocillium and Mortierella. This combination of CP and BC is a new concept that could encourages the development of a healthy and sustainable soil ecosystems while controlling plant pathogens.

Reductions in the quality and yield of crops continuously produced in the same location for many years due to annual increases in soil-borne pathogens. Environmentally-friendly methods are needed to produce vegetables sustainably and cost effectively under protective cover. We investigated the impact of biofertilizers on cucumber growth and yield, and changes to populations of soil microorganisms in response to biofertilizer treatments applied to substrate or soil. We observed that some biofertilizers significantly increased cucumber growth and decreased soil-borne pathogens in soil and substrate. Rhizosphere microbial communities in soil and substrate responded differently to different biofertilizers, which also led to significant differences in microbial diversity and taxonomic structure at different times in the growing season. Biofertilizers increase the prospects of re-using substrate for continuously producing high-quality crops cost-effectively from the same soil each year while at the same time controlling soil-borne disease.

Foodborne pathogens that enter the human food chain are a significant threat worldwide to human health. Timely and cost-effective detection of them became challenging for many countries that want to improve their detection and control of foodborne illness. We summarize simple, rapid, specific, and highly effective molecular technology that is used to detect and identify foodborne pathogens, including polymerase chain reaction, isothermal amplification, loop-mediated isothermal amplification, nucleic acid sequence-based amplification, as well as gene chip and gene probe technology. The principles of their operation, the research supporting their application, and the advantages and disadvantages of each technology are summarized.