Effects of seasonal harvest of kimchi cabbage on microbial and metabolic profiles of kimchi.

Kimchi cabbage, the key ingredient in kimchi, is cultivated year-round to meet high production demands. This study aimed to examine the effects of seasonal harvesting (spring, summer, fall, and winter) on the microbial and metabolic profiles of kimchi during 30 days of fermentation. Lactic acid bacteria distribution is notably influenced by seasonal variations, with Latilactobacillus dominant in fall-harvested kimchi group and Weissella prevailing in spring, summer, and winter. The microbial communities of spring and fall group exhibited similar profiles before fermentation, whereas the microbial communities and metabolic profiles of spring and summer group were similar after 30 days of fermentation. Seasonal disparities in metabolite concentrations, including glutamic acid, serine, and cytosine, persist throughout fermentation. This study provides a comprehensive understanding of the substantial impact of seasonal harvesting of kimchi cabbage on the microbial and metabolic characteristics of kimchi, providing valuable insights into producing kimchi with diverse qualities.

Effects of the Lactiplantibacillus plantarum YB-106 and Leuconostoc mesenteroides YB-23 strains on the quality and microbial diversity of spicy cabbage.

Spicy cabbage is a popular fermented vegetable food. The study aimed to determine the physicochemical properties, volatile flavor components, sensory evaluation, and microbial diversity of spicy cabbage prepared using different methods. Three methods were used: single-bacteria fermentation with Lactiplantibacillus plantarum YB-106 and Leuconostoc mesenteroides YB-23, mixed fermentation (LMP) using both strains, and natural fermentation as the blank control (CON). The LMP group has the best quality of spicy cabbage and the highest sensory score. Esters and alkenes were the main volatile flavor components of the spicy cabbage by GC-MS. The fermentation time of LMP group was shorter, and the nitrite degradation rate was >60 %, which was significantly higher than that of other groups (p < 0.05). From the perspective of microbial diversity, the dominant bacteria genera in each group were Lactobacillus, Pantoea, Enterococcus and Pseudomonas. However, mixed fermentation decreased the abundance of pathogenic bacteria, of which the abundance of Serratia was <0.1 %. In conclusion, mixed fermentation can significantly improve the quality of spicy cabbage and shorten the fermentation time. These findings laid the theoretical foundation for the industrial production of high-quality spicy cabbage.

Soil microorganisms play an important role in the detrimental impact of biodegradable microplastics on plants.

Biodegradable plastics were developed to mitigate environmental pollution caused by conventional plastics. Research indicates that biodegradable microplastics still have effects on plants and microorganisms as their non-biodegradable counterparts, yet the effects on vegetable crops are not well-documented. Additionally, the function of soil microorganisms affected by biodegradable microplastics on the fate of microplastics remains unverified. In this study, Brassica chinensis was cultivated in soil previously incubated for one year with low-density polyethylene (LDPE-MPs) and poly (butylene adipate-co-terephthalate) microplastics (PBAT-MPs) at 0.05 % and 2 % concentrations. High concentrations of PBAT-MPs significantly reduced the biomass to 5.83 % of the control. The abundance of Methyloversatilis, IS-44, and UTCFX1 in the rhizosphere bacterial community increased significantly in the presence of PBAT-MPs. Moreover, these microplastics significantly enhanced soil enzyme activity. Incubation tests were performed with three PBAT plastic sheets to assess the function of the altered bacterial community in the soil of control (Control-soil) and soil treated with high concentrations of PBAT-MPs (PBAT-MPs-soil). Scanning Electron Microscopy and Atomic Transfer Microscopy (SEM/ATM) results confirmed enhanced PBAT degradation in the PBAT-MPs-soil. PICRUST2 analysis revealed that pathways related to substance degradation were upregulated in the PBAT-MPs-soil. Furthermore, a higher percentage of strains with PBAT-MPs-degrading ability was found in PBAT-MPs-soil. Our results confirm that PBAT-MPs significantly inhibit the growth of vegetable crops and that soil bacterial communities affected by PBAT-MPs are instrumental in degrading them.

Identification and genomic insights into a strain of Bacillus velezensis with phytopathogen-inhibiting and plant growth-promoting properties.

The use of biological agents offers a sustainable alternative to chemical control in managing plant diseases. In this study, Bacillus velezensis IFST-221 was isolated from the rhizosphere of a healthy maize plant amidst a population showing severe disease symptoms. The investigation demonstrated a broad-spectrum antagonistic activity of IFST-221 against eight species of pathogenic ascomycetes and oomycetes, suggesting its potential utility in combating plant diseases like maize ear rot and cotton Verticillium wilt. Additionally, our study unveiled that IFST-221 has demonstrated significant plant growth-promoting properties, particularly in maize, cotton, tomato, and broccoli seedlings. This growth promotion was linked to its ability to produce indole-3-acetic acid, nitrogen fixation, phosphate and potassium solubilization, and biofilm formation in laboratory conditions. A complete genome sequencing of IFST-221 yielded a genome size of 3.858 M bp and a GC content of 46.71%. The genome analysis identified 3659 protein-coding genes, among which were nine secondary metabolite clusters with known antimicrobial properties. Additionally, three unknown compounds with potentially novel properties were also predicted from the genomic data. Genome mining also identified several key genes associated with plant growth regulation, colonization, and biofilm formation. These findings provide a compelling case for the application of B. velezensis IFST-221 in agricultural practices. The isolate's combined capabilities of plant growth promotion and antagonistic activity against common plant pathogens suggest its promise as an integrated biological agent in disease management and plant productivity enhancement.

Integrated Analysis of Transcriptome and Metabolome Reveals Differential Responses to Alternaria brassicicola Infection in Cabbage (Brassica oleracea var. capitata).

Black spot, caused by Alternaria brassicicola (Ab), poses a serious threat to crucifer production, and knowledge of how plants respond to Ab infection is essential for black spot management. In the current study, combined transcriptomic and metabolic analysis was employed to investigate the response to Ab infection in two cabbage (Brassica oleracea var. capitata) genotypes, Bo257 (resistant to Ab) and Bo190 (susceptible to Ab). A total of 1100 and 7490 differentially expressed genes were identified in Bo257 (R_mock vs. R_Ab) and Bo190 (S_mock vs. S_Ab), respectively. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that "metabolic pathways", "biosynthesis of secondary metabolites", and "glucosinolate biosynthesis" were the top three enriched KEGG pathways in Bo257, while "metabolic pathways", "biosynthesis of secondary metabolites", and "carbon metabolism" were the top three enriched KEGG pathways in Bo190. Further analysis showed that genes involved in extracellular reactive oxygen species (ROS) production, jasmonic acid signaling pathway, and indolic glucosinolate biosynthesis pathway were differentially expressed in response to Ab infection. Notably, when infected with Ab, genes involved in extracellular ROS production were largely unchanged in Bo257, whereas most of these genes were upregulated in Bo190. Metabolic profiling revealed 24 and 56 differentially accumulated metabolites in Bo257 and Bo190, respectively, with the majority being primary metabolites. Further analysis revealed that dramatic accumulation of succinate was observed in Bo257 and Bo190, which may provide energy for resistance responses against Ab infection via the tricarboxylic acid cycle pathway. Collectively, this study provides comprehensive insights into the Ab-cabbage interactions and helps uncover targets for breeding Ab-resistant varieties in cabbage.

The ilv2 gene, encoding acetolactate synthase for branched chain amino acid biosynthesis, is required for plant pathogenicity by Leptosphaeria maculans.

BACKGROUND: Control of blackleg disease of canola caused by the fungus Leptosphaeria maculans relies on strategies such as the inhibition of growth with fungicides. However, other chemicals are used during canola cultivation, including fertilizers and herbicides. There is widespread use of herbicides that target the acetolactate synthase (ALS) enzyme involved in branched chain amino acid synthesis and low levels of these amino acids within leaves of Brassica species. In L. maculans the ilv2 gene encodes ALS and thus ALS-inhibiting herbicides may inadvertently impact the fungus. METHODS AND RESULTS: Here, the impact of a commercial herbicide targeting ALS and mutation of the homologous ilv2 gene in L. maculans was explored. Exposure to herbicide had limited impact on growth in vitro but reduced lesion sizes in plant disease experiments. Furthermore, the mutation of the ilv2 gene via CRISPR-Cas9 gene editing rendered the fungus non-pathogenic. CONCLUSION: Herbicide applications can influence disease outcome, but likely to a minor extent.

Effect of polyethylene microplastics on antibiotic resistance genes: A comparison based on different soil types and plant types.

Microplastics (MPs) and antibiotic resistance genes (ARGs) are two types of contaminants that are widely present in the soil environment. MPs can act as carriers of microbes, facilitating the colonization and spread of ARGs and thus posing potential hazards to ecosystem safety and human health. In the present study, we explored the microbial networks and ARG distribution characteristics in different soil types (heavy metal (HM)-contaminated soil and agricultural soil planted with different plants: Bidens pilosa L., Ipomoea aquatica F., and Brassica chinensis L.) after the application of MPs and evaluated environmental factors, potential microbial hosts, and ARGs. The microbial communities in the three rhizosphere soils were closely related to each other, and the modularity of the microbial networks was greater than 0.4. Moreover, the core taxa in the microbial networks, including Actinobacteriota, Proteobacteria, and Myxococcota, were important for resisting environmental stress. The ARG resistance mechanisms were dominated by antibiotic efflux in all three rhizosphere soils. Based on the annotation results, the MP treatments induced changes in the relative abundance of microbes carrying ARGs, and the G1-5 treatment significantly increased the abundance of MuxB in Verrucomicrobia, Elusimicrobia, Actinobacteria, Planctomycetes, and Acidobacteria. Path analysis showed that changes in MP particle size and dosage may indirectly affect soil enzyme activities by changing pH, which affects microbes and ARGs. We suggest that MPs may provide surfaces for ARG accumulation, leading to ARG enrichment in plants. In conclusion, our results demonstrate that MPs, as potentially persistent pollutants, can affect different types of soil environments and that the presence of ARGs may cause substantial environmental risks.

Study of cabbage antioxidant system response on early infection stage of Xanthomonas campestris pv. campestris.

Black rot, caused by Xanthomonas campestris pv. campestris (Xcc) significantly affects the production of cabbage and other cruciferous vegetables. Plant antioxidant system plays an important role in pathogen invasion and is one of the main mechanisms underlying resistance to biological stress. Therefore, it is important to study the resistance mechanisms of the cabbage antioxidant system during the early stages of Xcc. In this study, 108 CFU/mL (OD600 = 0.1) Xcc race1 was inoculated on "zhonggan 11" cabbage using the spraying method. The effects of Xcc infection on the antioxidant system before and after Xcc inoculation (0, 1, 3, and 5 d) were studied by physiological indexes determination, transcriptome and metabolome analyses. We concluded that early Xcc infection can destroy the balance of the active oxygen metabolism system, increase the generation of free radicals, and decrease the scavenging ability, leading to membrane lipid peroxidation, resulting in the destruction of the biofilm system and metabolic disorders. In response to Xcc infection, cabbage clears a series of reactive oxygen species (ROS) produced during Xcc infection via various antioxidant pathways. The activities of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) increased after Xcc infection, and the ROS scavenging rate increased. The biosynthesis of non-obligate antioxidants, such as ascorbic acid (AsA) and glutathione (GSH), is also enhanced after Xcc infection. Moreover, the alkaloid and vitamin contents increased significantly after Xcc infection. We concluded that cabbage could resist Xcc invasion by maintaining the stability of the cell membrane system and improving the biosynthesis of antioxidant substances and enzymes after infection by Xcc. Our results provide theoretical basis and data support for subsequent research on the cruciferous vegetables resistance mechanism and breeding to Xcc.

Field-based investigation reveals selective enrichment of companion microbes in vegetables leading to specific accumulation of antibiotic resistance genes.

Vegetables capture antibiotic resistance genes (ARGs) from the soil and then pass them on to consumers through the delivery chain and food chain, and are therefore the key node that may increase the risk of human exposure to ARGs. This study investigates the patterns and driving forces behind the transmission of ARGs from soil to vegetables by the commonly planted cash crops in the coastal region of southern China, i.e. broccoli, pumpkin, and broad bean, to investigate. The study used metagenomic data to reveal the microbial and ARGs profiles of various vegetables and the soil they are grown. The results indicate significant differences in the accumulation of ARGs among different vegetables harvested in the same area at the same time frame, and the ARGs accumulation ability of the three vegetables was in the order of broccoli, broad bean, and pumpkin. In addition, broccoli collected the highest number of ARGs in types (n = 14), while pumpkin (n = 13) does not obtain trimethoprim resistance genes and broad beans (n = 10) do not obtain chloramphenicol, fosmidomycin, quinolone, rifamycin, or trimethoprim resistance genes. Host tracking analysis shows a strong positive correlation (|rho| > 0.8, p < 0.05) between enriched ARGs and plant companion microbes. Enrichment analysis of metabolic pathways of companion microbes shows that vegetables exhibit a discernible enrichment of companion microbes, with significant differences among vegetables. This phenomenon is primarily due to the screening of carbohydrate metabolism capabilities among companion microbes and leads varied patterns of ARGs that spread from the soil to vegetables. This offers a novel insight into the intervention of foodborne transmission of ARGs.

Functional characterization and transcriptional analysis of degQ of Xanthomonas campestris pathovar campestris.

High-temperature-requirement protein A (HtrA) family proteins play important roles in controlling protein quality and are recognized as virulence factors in numerous animal and human bacterial pathogens. The role of HtrA family proteins in plant pathogens remains largely unexplored. Here, we investigated the HtrA family protein, DegQ, in the crucifer black rot pathogen Xanthomonas campestris pathovar campestris (Xcc). DegQ is essential for bacterial attachment and full virulence of Xcc. Moreover, the degQ mutant strain showed increased sensitivity to heat treatment and sodium dodecyl sulfate. Expressing the intact degQ gene in trans in the degQ mutant could reverse the observed phenotypic changes. In addition, we demonstrated that the DegQ protein exhibited chaperone-like activity. Transcriptional analysis displayed that degQ expression was induced under heat treatment. Our results contribute to understanding the function and expression of DegQ of Xcc for the first time and provide a novel perspective about HtrA family proteins in plant pathogen.

Carpogenic germination of Sclerotinia sclerotiorum sclerotia in Brassica oleracea var gemmifera (VN: Brussels sprouts) in North Patagonia, Argentina.

In August 2018, symptoms of apical and basal rot resembling those caused by Sclerotinia sclerotiorum infection were observed in a commercial Brussels sprouts field in North Patagonia, Argentina. The incidence of apical and basal rot was 23.30% and 2.30%, respectively. Carpogenic germination of sclerotia was detected in shaded, highly humid soil areas. To our knowledge, this is the first report of carpogenic germination of sclerotia from S. sclerotiorum in North Patagonia.

Compatibility of the fungus Beauveria bassiana and Trichoplusia ni SNPV against the cabbage looper Trichoplusia ni: crop plant matters.

BACKGROUND: Microbial insecticides are an important weapon in insect pest management, but their use is still relatively limited. One approach for increasing their efficacy and use could be to combine different pathogens to increase pest mortality. However, little is known about whether increasing pathogen diversity will improve pest management. Here, we investigated the compatibility of two pathogens for the management of the cabbage looper, Trichoplusia ni, T. ni nucleopolyhedrovirus (TniSNPV) and the entomopathogenic fungus Beauveria bassiana, on two crops, tomato and broccoli. The pathogens were applied to individual plants using ultra low volume sprays, alone or in combination, either synchronously or asynchronously. Healthy third-instar T. ni larvae were introduced to the plants before application and collected by destructive sampling 24 h after the last pathogen application. RESULTS: Combined applications did not result in an increase in larval mortality compared to TniSNPV alone, although mortality was generally high. B. bassiana was considerably less effective on broccoli compared to tomato. In both the combined treatments, virus-induced mortality was approximately 50% lower when applied together with the fungus, while fungus-induced mortality was not affected by the virus, even when the virus was introduced 24 h before the fungus. CONCLUSION: While our results suggest that applying this combination of entomopathogens would not be beneficial for pest management, this study illustrates the need to consider the target crop as an important driver of the efficacy of both single and mixed pathogen applications in the field. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Characterisation of New Foxunavirus Phage Murka with the Potential of Xanthomonas campestris pv. campestris Control.

Phages of phytopathogenic bacteria are considered to be promising agents for the biological control of bacterial diseases in plants. This paper reports on the isolation and characterisation of a new Xanthomonas campestris pv. campestris phage, Murka. Phage morphology and basic kinetic characteristics of the infection were determined, and a phylogenomic analysis was performed. The phage was able to lyse a reasonably broad range (64%, 9 of the 14 of the Xanthomonas campestris pv. campestris strains used in the study) of circulating strains of the cabbage black rot pathogen. This lytic myovirus has a DNA genome of 44,044 bp and contains 83 predicted genes. Taxonomically, it belongs to the genus Foxunavirus. This bacteriophage is promising for use as a possible means of biological control of cabbage black rot.

The gain effect of microbial consortia induced by adaptive domestication for efficient conversion of Chinese cabbage waste by anaerobic fermentation.

The resource-based treatment of Chinese cabbage waste by anaerobic fermentation can effectively mitigate air, soil, and groundwater pollution. However, the compatibility between fermentative microorganisms and the environment might be a crucial limiting factor for the resource recycling of Chinese cabbage waste. Therefore, the gain effect of microbial consortia (JMRS, JMRST, JMRSZ, JCCW, JCCWT and JCCWZ) induced by adaptive domestication for efficient conversion of Chinese cabbage waste by anaerobic fermentation were explored in this study. A total of 42 single subsamples with same weights were randomly divided into seven treatments: sterile deionized water (Control); anaerobic fermentation inoculated with JMRS (MRS); anaerobic fermentation inoculated with JMRST (MRST); anaerobic fermentation inoculated with JMRSZ (MRSZ); anaerobic fermentation inoculated with JCCW (CCW); anaerobic fermentation inoculated with JCCWT (CCWT); anaerobic fermentation inoculated with JCCWZ (CCWZ) and samples were taken on days 30 and 60 after anaerobic fermentation. The results exhibited that all the treatments contributed to high levels of lactic acid (178.77-201.79 g/kg dry matter) and low levels of ammonia-N (12.99-21.03 g/kg total nitrogen). Meanwhile, MRSZ enhanced (p < 0.05) acetic acid levels (1.53 g/kg dry matter) and resulted in the lowest yeast counts. Microbiologically, the addition of microbial consortia decreased the linear discriminant analysis (LDA) scores of Massilia and Stenotrophomonas maltophilia. Moreover, MRSZ enriched (p < 0.05) Lactobacillus hilgardii, and decreased (p < 0.05) the abundance of bacteria containing mobile elements and potentially pathogenic bacteria. In conclusion, JMRSZ improved the efficient conversion of Chinese cabbage waste for resource utilization.

Prolonging broccoli shelf life through controlled release of plai essential oil using palm wood sachet as a novel absorbent material with reusable properties.

Palm wood powder derived from palm wood waste was utilized as a novel absorbent material. The investigation involved exploring its pore structure and size to achieve the controlled release of bioactive compounds from plai oil, providing protection against pathogenic bacteria and thereby extending the shelf life of broccoli. The palm wood sachet was prepared before being placed into the broccoli bag. The process to create the sachet involved freezing the palm wood at -10°C and then drying it at a temperature of 200°C. After drying, the material was ground to achieve a particle size of 20 mesh and then packaged into sachets made from wood pulp. The optimized palm wood plai oil sachet (PWPS), measuring 5 × 7 cm, with a thickness of 0.58 µm, was produced by soaking 2 g of palm powder in plai oil at a concentration of 30 µL/mL before drying and packing it inside a 5-L polyethylene plastic bag (24 × 34 cm) along with broccoli (150 g). The packages were kept at 4°C for 20 days to determine the antimicrobial activity of the PWPS and broccoli quality. PWPS significantly inhibited the growth of Escherichia coli, Salmonella Typhimurium, Staphylococcus aureus, and Listeria monocytogenes in broccoli for at least 20 days. The sachet demonstrated complete inhibition of all bacteria when reused at least two times and an 80% reduction in efficacy after three uses. Moreover, the PWPS controlled the growth of total aerobic bacteria and yeast and mold in broccoli, meeting microbiological criteria for up to 14 days. Broccoli stored with PWPS showed good quality results and contained high antioxidant value. These results demonstrate the potential application of PWPS in controlling food pathogens and spoilage microbes during storage. PRACTICAL APPLICATION: This study introduces a novel absorbent material made from palm wood powder, addressing the need for utilizing abundant waste palm wood in the food industry. The material benefits the safe transportation of vegetables from farms to markets. Its porous structure allows efficient absorption of plai oil emulsion, ensuring pathogen-free and high-quality treated broccoli. The reusable sachets benefit farmers seeking to extend the shelf life of fresh produce. This cost-effective method utilizes plai oil vapor, making it suitable for large-scale production.

Viability of sublethally injured indicator and pathogenic coliform bacteria on fresh-cut cabbage during storage in an active MAP of 10% CO2.

Shredded cabbage treated with either tap water or electrolyzed water was stored in an active modified atmosphere packaging (MAP) of 10% CO2 for 5 d at 10℃, 7 d at 5℃, and 8 d at 1℃ to evaluate the occurrence and viability of sublethally injured coliform bacteria. The CO2 and O2 concentrations in the packages approached an equilibrium of 10% CO2 and 10% O2 during storage at all temperatures tested. Coliforms in shredded cabbage increased during storage at all three temperatures, with the increase being greater at 10℃. Sublethal injury at 65% to 69% for the coliforms was detected only on cabbage samples treated with electrolyzed water and stored at 5℃ for 4 and 7 d. Enterobacter cloacae was one of the injured species of coliform bacteria in shredded cabbage. Shredded cabbage was inoculated with chlorine-injured Escherichia coli O157:H7 and stored at 5℃ for 6 d in an active MAP of 10% CO2. Counts of E. coli O157:H7 remained almost constant during storage, and injured E. coli O157:H7 ranging from 50% to 70% were found on shredded cabbage throughout the storage period. These results indicate that sublethally injured indicator and pathogenic bacteria would be found on fresh-cut cabbage in the realistic MAP storage at 5℃.

Assessment of CuO NPs on soil microbial community structure based on phospholipid fatty acid techniques and phytotoxicity of bok choy seedlings.

In this study, a soil culture and a hydroponic experiment were conducted to assess the toxicology effects of copper oxide nanoparticles (CuO NPs) on soil microbial community structure and the growth of bok choy. Results showed CuO NPs had an inhibitory effect on soil microbial abundance, diversity, and activity, as well as the bok choy seedling growth, whereas CuO NPs at low concentrations did not significantly affect the soil microbial biomass or plant growth. In soil, CuO NPs at high dose (80 mg kg-1) significantly reduced the indexes of Simpson diversity, Shannon-Wiener diversity and Pielou evenness by 3.7%, 4.9% and 4.5%, respectively. In addition, CuO NPs at 20 and 80 mg kg-1 treatment significantly reduced soil enzymes (urease, alkaline phosphatase, dehydrogenase, and catalase) activities by 25.5%-58.9%. Further, CuO NPs at 20 mg L-1 significantly inhibited the growth of plant root by 33.8%, and catalase (CAT) activity by 17.9% in bok choy seedlings. The present study can provide a basis for a comprehensive evaluation of the toxicity effect of CuO NPs on soil microorganisms and phytotoxicity to bok choy seedlings.

Occurrence, Characteristics, and qPCR-Based Identification of Pectobacterium versatile Causing Soft Rot of Chinese Cabbage in China.

Pectobacterium is one of the most important genera of phytopathogenic bacteria. It can cause soft-rot diseases on a wide range of plant species across the world. In this study, three Pectobacterium strains (KC01, KC02, and KC03) were isolated from soft-rotted Chinese cabbage in Beijing, China. These three strains were identified as Pectobacterium versatile based on phylogenetic analysis of Pectobacterium 16S ribosomal RNA, pmrA, and 504 Pectobacterium core genes, as well as a genomic average nucleotide identity analysis. Their biochemical characteristics were found to be similar to the P. versatile type strain ICMP9168T but differed in response to citric acid, stachyose, D-glucuronic acid, dextrin, and N-acetyl-ß-D-mannosamine. All of the tested P. versatile strains showed different carbohydrate utilization abilities compared with P. carotovorum and P. odoriferum, particularly in their ability to utilize D-arabitol, L-rhamnose, and L-serine. Under laboratory conditions, the maceration ability of P. versatile on Chinese cabbage was the highest at 28°C, compared with those at 13, 28, 23, and 33°C. Additionally, P. versatile could infect all of the 17 known Pectobacterium host plants, except for Welsh onion (Allium fistulosum). A SYBR Green quantitative PCR (qPCR) detection system was developed to distinguish P. versatile from other soft-rot bacteria based on the combined performance of melting curve (with a single melting peak at around 85°C) and fluorescence curve (with cycle threshold <30) when the bacterial genomic DNA concentration was in the range of 10 pg/µl to 10 ng/µl. This study is the first to report the presence of P. versatile on Chinese cabbage in China, as well as a specific and sensitive qPCR assay that can be used to quickly identify P. versatile. The work contributes to a better understanding of P. versatile and will facilitate the effective diagnosis of soft-rot disease, ultimately benefitting commercial crop production.

Effect of composted pig manure, biochar, and their combination on antibiotic resistome dissipation in swine wastewater-treated soil.

The prevalence of antibiotic resistance genes (ARGs), owing to irrigation using untreated swine wastewater, in vegetable-cultivated soils around swine farms poses severe threats to human health. Furthermore, at the field scale, the remediation of such soils is still challenging. Therefore, here, we performed field-scale experiments involving the cultivation of Brassica pekinensis in a swine wastewater-treated soil amended with composted pig manure, biochar, or their combination. Specifically, the ARG and mobile genetic element (MGE) profiles of bulk soil (BS), rhizosphere soil (RS), and root endophyte (RE) samples were examined using high-throughput quantitative polymerase chain reaction. In total, 117 ARGs and 22 MGEs were detected. Moreover, we observed that soil amendment using composted pig manure, biochar, or their combination decreased the absolute abundance of ARGs in BS and RE after 90 days of treatment. However, the decrease in the abundance of ARGs in RS was not significant. We also observed that the manure and biochar co-application showed a minimal synergistic effect. To clarify this observation, we performed network and Spearman correlation analyses and used structure equation models to explore the correlations among ARGs, MGEs, bacterial composition, and soil properties. The results revealed that the soil amendments reduced the abundances of MGEs and potential ARG-carrying bacteria. Additionally, weakened horizontal gene transfer was responsible for the dissipation of ARGs. Thus, our results indicate that composted manure application, with or without biochar, is a useful strategy for soil nutrient supplementation and alleviating farmland ARG pollution, providing a justification for using an alternative to the common agricultural practice of treating the soil using only untreated swine wastewater. Additionally, our results are important in the context of soil health for sustainable agriculture.

Use of Vegetable Waste as a Culture Medium Ingredient Improves the Antimicrobial and Immunomodulatory Activities of Lactiplantibacillus plantarum WiKim0125 Isolated from Kimchi.

Lactic acid bacteria (LAB) isolated from kimchi (a traditional Korean dish typically made of fermented cabbage) can provide various health benefits, including anti-obesity, antioxidant, anti-inflammatory, anticancer, and antimicrobial effects. In this study, we examined the antimicrobial and immunomodulatory effects of Lactiplantibacillus plantarum WiKim0125 cultured in de Man, Rogosa, and Sharpe (MRS) medium containing vegetable waste. Live bacterial cells were eliminated via supernatant filtration or heat treatment. The cell-free supernatant (CFS) obtained from culture broth containing kimchi cabbage waste (KCW), cabbage waste (CW), or onion waste (OW) showed significantly higher antimicrobial activity against skin pathogens (Propionibacterium acnes and Staphylococcus aureus) and foodborne pathogens (Escherichia coli and Salmonella typhimurium), with inhibition zones ranging between 4.4 and 8.5 mm, compared to that in conventional MRS medium (4.0-7.3 mm). In lipopolysaccharide-stimulated RAW264.7 cells, both supernatant and heat-inactivated Lb. plantarum WiKim0125 from culture media containing KCW and CW suppressed the production of inflammatory cytokines (72.8% and 49.6%, respectively) and nitric oxide (62.2% and 66.7%, respectively) without affecting cell viability. These results indicate that vegetable waste can potentially increase the antimicrobial and immunoregulatory potency of LAB while presenting a molecular basis for applying postbiotics to health products.