Search Results (30)

The use of untreated livestock manure in urban agriculture sustains soil fertility but risks disseminating antimicrobial resistance (AMR) in resource-limited settings. This study characterized antibiotic-resistant bacteria (ARB) prevalence across manure–soil–vegetable pathways in Blantyre, Malawi. Using a cross-sectional design, we collected 35 samples (poultry/pig manure, farm/home soils, Brassica rapa subsp. chinensis, Brassica rapa, and Amaranthus spp.) from five livestock farms. Microbiological analysis with API 20E identification and disk diffusion testing revealed clear differences in contamination: Escherichia coli dominated pig manure (52%) and farm soil (35%), with detection in vegetables suggesting possible transfer (e.g., 20% in Brassica rapa subsp. chinensis), while Klebsiella pneumoniae contaminated all sample types (peak: 60% vegetables and 67% home soils). All manure isolates exhibited sulfamethoxazole–trimethoprim resistance, with 50% of pig manure E. coli showing cefotaxime resistance. Soil isolates mirrored these patterns (100% ampicillin resistance in K. pneumoniae and 77% cefotaxime resistance in farm soil E. coli). Vegetables displayed severe multidrug resistance (100% E. coli and 80% K. pneumoniae resistant to ≥3 classes), including critical gentamicin resistance (100% E. coli). Composting for ≤6 weeks, as practiced on the studied farms, did not eliminate ARBs, suggesting that longer durations may be needed. Notably, this study provides the first phenotypic evidence of presumptive Pasteurella-like organisms on edible leafy vegetables, specifically 45% in Amaranthus spp. and 6.1% in Brassica rapa, suggesting a potential zoonotic transmission route from livestock farms that requires molecular confirmation. These findings demonstrate manure-amended farms as AMR reservoirs, necessitating extended composting and antibiotic stewardship to mitigate One Health risks. Full article

Heat stress, intensified by global warming, is an increasing challenge for the growth and yield of the economically important crop Brassica rapa subsp. chinensis (NHCC). The Heat Shock Protein 70 (HSP70) family plays an important role in plant thermotolerance, but its molecular characteristics and regulatory mechanisms in this subspecies have not been investigated. Herein, we conducted a comprehensive genomic and transcriptional profiling of the BrcHSP70 gene lineage and revealed a total of 31 members. Our phylogenetic analysis revealed a closer evolutionary relationship to genes from B. rapa ssp. pekinensis (HCC) than to those found in Arabidopsis. Genomic analysis demonstrated that segmental duplication, with eight pairs identified, was the primary driving force for the family’s expansion, rather than tandem duplication. Additionally, the BrcHsp70 gene promoters are enriched with cis-acting elements responsive to phytohormones (particularly ABA) and abiotic stresses. Critically, under 38 °C high-temperature stress, the heat-resistant variety ‘SHI’ and heat-sensitive variety ‘Aijiaohuang’ exhibited distinct expression patterns, identifying key candidate genes implicated in thermotolerance. These results elucidate the evolutionary and regulatory features of the HSP70 family in NHCC, providing a new understanding of the molecular mechanisms of plant heat tolerance. Full article

Branching is a critical agronomic trait in flowering Chinese cabbage (Brassica rapa subsp. chinensis), influencing plant architecture and yield. In this study, there was a highly significant difference between CX010 (single primary rosette branches) and BCT18 (multiple primary rosette branches). Phenotypic analysis revealed significant differences in primary rosette branch numbers, with BCT18 showing up to 15 branches and CX010 displaying only one main stem branch. Genetic analysis indicated that branching was controlled by quantitative trait loci (QTL) with a normal distribution of branch numbers. Using bulked segregant analysis coupled with sequencing (BSA-seq), we identified a candidate interval of approximately 2.96 Mb on chromosome A07 linked to branching. Fine mapping narrowed this to a 172 kb region containing 29 genes, with BraA07g032600.3C (BrTCP1) as the most likely candidate. cDNA cloning of the BrTCP1 gene revealed several variations in BCT18 compared to CX010, including a 6 bp insertion, 10 SNPs, and two single-nucleotide deletions. Expression analysis indicated that BrTCP1 was highly expressed in the rosette stems of CX010 compared to BCT18, consistent with its role as a branching suppressor. The heterologous mutants in Arabidopsis confirmed the conserved role of BrTCP1 in branch inhibition. These findings reveal that BrTCP1 might be a key regulator of branching in flowering Chinese cabbage, providing insights into the molecular mechanisms underlying this trait and offering a framework for genetic improvement in Brassica crops. Full article

Background: Equally with other indigenous green leafy vegetables, Solunum nigrum L. has been widely consumed by the VhaVenda tribe found in the Limpopo Province of South Africa since ancient times as a source of food diversification due to its higher-quality nutritional value, sustainability, food security, and medicinal benefits. It is mostly cultivated from seeds in seedling trays and transplanted in the open field, and at the maturity stage, marketing and distribution are mainly conducting through informal markets (i.e., street vendors). However, recently, it can be found in selected supermarkets and commercial grocery stores in South Africa. The leaves and young shoots of S. nigrum are cooked solely and/or as a supplementary vegetable with Brassica rapa L. subsp. chinensis (Chinese cabbage), Spinacia oleracea L. (spinach), Amaranthus graecizans L. (green amaranth), Solanum lycopersicum L. (tomato), and/or cooking oil for flavor. Objective: Contrary to other green leafy vegetables, few studies have been conducted on the metabolites released by S. nigrum and the influence of growing conditions on the metabolites thereof. Method: A ¹H-nuclear magnetic resonance tool was used to identify the untargeted metabolites released by S. nigrum, and spectra were phase-corrected and binned with MestReNova and statistically analyzed with SIMCA 18.0.2. Results: The findings showed that a total of 12 metabolites were detected between the growing conditions. Eleven similar metabolites, such as glycocholate, chlorogenate (human health benefits), caffeine for its bitter taste, choline, 3-Chlorotyrosine (antidiabetic, blood pressure), etc., and a few vital soluble sugars, were detected in S. nigrum samples grown in the open field and greenhouse-cultivated. Glucose was exclusively detected in the S. nigrum grown under greenhouse conditions. Full article

The accumulation of heavy metal cadmium (Cd) in farmland soil in edible parts of crops seriously threatens plant growth, human health, and even the global ecological environment. Finding stabilization remediation technology is an important means to treat Cd-contaminated soil. This study comprehensively evaluated the synergistic effects of independent or combined application of biochar (BC) (10, 30 g kg⁻¹) and nano zero-valent iron (nZVI) (0.1% w/w) on soil properties and morphological and physiological traits of pakchoi (Brassica rapa L. subsp. chinensis) under Cd (1, 3 mg kg⁻¹) stress by pot experiments. It was shown that Cd toxicity negatively affected soil properties, reduced pakchoi biomass and total chlorophyll content, and increased oxidative stress levels. On the contrary, the combined application of BC (30 g kg⁻¹) and nZVI (0.1%, w/w) reduced the Cd accumulation in the shoot parts of pakchoi from 0.78 mg·kg⁻¹ to 0.11 mg·kg⁻¹, which was lower than the Cd limit standard of leafy vegetables (0.20 mg kg⁻¹) in GB 2762-2017 “National Food Safety Standard”. Compared with the control, the treatment group achieved a 61.66% increase in biomass and a 105.56% increase in total chlorophyll content. At the same time, the activities of catalase (CAT) and superoxide dismutase (SOD) increased by 34.86% and 44.57%, respectively, and the content of malondialdehyde (MDA) decreased by 71.27%. In addition, the application of BC alone (30 g·kg⁻¹) increased the soil pH value by 0.43 units and the organic carbon (SOC) content by 37.82%. Overall, the synergistic effect of BC (30 g kg⁻¹) and nZVI (0.1% w/w) helped to restore soil homeostasis and inhibit the biotoxicity of Cd, which provided a new option for soil heavy metal remediation and crop toxicity mitigation. Full article

Biofertilizers derived from microalgae are increasingly used as promising materials for improving crop growth and development, producing fewer catastrophic environmental effects. Hence, the large-scale production of eco-friendly and broad-spectrum microalgae biofertilizers is mandatory. Therefore, this study was designed to examine the potential efficacy of isolated algae strains, such as Spirulina platensis, Spirulina maxima, and Chlorella vulgaris, to improve the growth and development of Pak Choi. A completely randomized design (CRD) was carried out, with five replications and six levels (0, 0.5, 1.0, 1.5, 2.0, and 2.5 g) of each microalga biofertilizer, using Pak Choi as the test plant. Treatment with microalgae biofertilizers was found to increase Pak Choi’s overall growth performance, biochemical development, and nutritional composition. The application of Spirulina platensis and Spirulina maxima microalgae at 2 g as a biofertilizer showed significant (p < 0.05) positive impacts on above- and below-ground biomass, photosynthetic parameters, biochemical composition, and the nutritional attributes of different parts of Pak Choi tissues. With the addition of biofertilizer, incorporating Chlorella vulgaris (2.5 g) showed remarkable (p < 0.05) impacts on the development of above- and below-ground biomass and biochemical and nutritional attributes. Thus, our results highlight that Chlorella vulgaris (2.5 g) outperforms other biofertilizer treatments and could be considered a sustainable approach for producing leafy vegetables. Full article

Postharvest leaf senescence is a pivotal determinant influencing the quality and shelf life of leafy vegetables, exemplified by pak choi (Brassica rapa L. subsp. chinensis). While the regulatory role of gibberellin (GA) in modulating leaf senescence has been documented across diverse plant species, the underlying physiological and molecular mechanisms remain insufficiently characterized. This study, through a combination of transcriptomic and metabolomic analyses, investigated the effect of exogenous GA on postharvest leaf senescence in pak choi. GA treatment alleviated etiolation, maintained chlorophyll levels, reduced conductivity and malondialdehyde content, and delayed the onset of senescence symptoms in postharvest pak choi. Transcriptome profiling indicated that GA suppressed the expression of the senescence-associated genes BraSRGs and BraSAGs. In addition, GA influenced chlorophyll degradation and preserved chlorophyll content by modulating the expression of genes implicated in chlorophyll metabolism, including BraPPH, BraSGR1, BraNYCI, and BraPAO. GA treatment impacted lipid levels and regulated the degradation of membrane phospholipids. Furthermore, exogenous GA treatment disrupted the efficacy of the jasmonic acid signal pathway, primarily through the transcriptional downregulation of key regulatory genes, including BraJAZ10 and BraJAR1. These results provide insights into the role of GA in delaying postharvest leaf senescence and highlight potential targets for improving postharvest management in leafy vegetables. Full article

This study investigated the effects of dietary iron supplementation on water quality, plant growth, and fish health in an aquaponic system over 90 days. Iron supplementation significantly improved plant growth, with increased plant height, stem diameter, leaf count, and fruit yield in tomatoes (Solanum lycopersicum) and pak choi (Brassica rapa subsp. Chinensis) (p < 0.05). The water pH fluctuated with varying iron content, and higher iron levels promoted better plant growth by improving iron availability (p < 0.05). During the first 60 days, all red blood cell counts and hemoglobin levels increased, but the growth and nutritional composition of mirror carp (Cyprinus carpio var. specularis) showed no significant differences. By day 90, fish in the T3 group (800 mg/kg iron) exhibited significantly reduced growth and feed conversion rates (p < 0.05). Histological analysis of liver tissue indicated iron-induced liver damage; additionally, excessive iron intake suppressed erythropoiesis, leading to lower red blood cell counts and hemoglobin levels (p < 0.05). The results indicate that moderate iron supplementation improves plant growth, but excessive iron can negatively impact fish health, particularly liver function and blood formation. These findings provide valuable insights for optimizing iron levels in aquaponic systems. Full article

This study was aimed at problems associated with low fertilizer using efficiency, excessive nitrate content of vegetables, and soil degradation in greenhouse vegetable production. A pot experiment was conducted to assess the effects of applying biochar-coated nitrogen fertilizer (BCNF) on the yield, quality, and nitrate content of bok choy (Brassica rapa subsp. Chinensis) as well as on soil nutrients in greenhouses. Four treatments were set up as follows: no nitrogen fertilizer application (BA), chemical nitrogen fertilizer application (CK), biochar-coated nitrogen fertilizer application (BCNF, the amount of nitrogen was equal to that of chemical fertilizer), and reduced biochar-coated nitrogen fertilizer application (D-BCNF, the amount of fertilizer was 80% of BCNF). Compared with the other treatments, BCNF treatment increased chlorophyll content, plant height, maximum leaf length, maximum leaf width, and other biological characters of bok choy. Compared with CK treatment, BCNF treatment increased the fresh weight of bok choy by 14.02%, while reducing the root–shoot ratio and nitrate content by 19.1% and 46%, respectively. It was further found that the application of BCNF could effectively increase the content of soil organic matter; reduce the leaching loss of nitrate nitrogen, exchangeable calcium and magnesium; and effectively improve nitrogen use efficiency. Therefore, the application of BCNF can not only reduce the loss of fertilizer nutrients, promote plant growth, and improve fertilizer utilization, but it can also improve soil nutrients, fix carbon, and reduce emissions. It is a new type of environmental protection fertilizer with application prospects. Full article

Glucosinolates are sulfur-containing phytochemicals generally abundant in cruciferous vegetables such as pak choy. Glucosinolates participate in a range of biological activities essential for promoting a healthy human body. In this study, we aimed to elucidate glucosinolate variability present in pak choy germplasm that are under conservation at the Rural Development Administration Genebank, Jeonju, Republic of Korea. The Acquity Ultra-Performance Liquid Chromatography (UHPLC) analytical system was used in profiling the glucosinolate content in leaf samples of various accessions. We identified a total of 17 glucosinolates in the germplasm. Based on principal compoment analysis performed, three separate groups of the accessions were obtained. Group 1 contained the cultivar cheongsacholong which recorded high content of glucobrassicin (an indole), glucoerucin (aliphatic), gluconasturtiin (aromatic) and glucoberteroin (aliphatic). Group 2 consisted of six accessions, BRA77/72, Lu ling gaogengbai, 9041, Wuyueman, RP-75 and DH-10, predominatly high in aliphatic compounds including glucoiberin, glucocheirolin, and sinigrin. Group 3 comprised the majority of the accessions which were characterized by high content of glucoraphanin, epiprogoitrin, progoitrin, and glucotropaeolin. These results revealed the presence of variability among the pak choy germplasm based on their glucosinolate content, providing an excellent opprtunity for future breeding for improved glucosinolate content in the crop. Full article

Salinity stress poses a significant challenge to Pak Choi (Brassica rapa subsp. Chinensis) production. To address this limitation, we conducted an evaluation of 24 Korean native Pak Choi species to identify genotypes with resistance to salt stress. Through cluster analysis of electrolyte leakage data, we discovered ‘IT262109’, ‘IT279432’, and ‘IT185735’ as native accessions displaying the strongest salt tolerance. Additionally, our assessment of the maximum quantum yield of photosystem II revealed a 3.7% reduction in seaweed yield in the highly salt-tolerant system compared with the control group, while the weak salt-tolerant system experienced a substantial reduction rate of 45.7% to 49.4%. Notably, salt stress had a significant impact on Pak Choi growth, but the salt-tolerant genotype exhibited less growth reduction compared with the salt-sensitive genotype. Based on the electrolyte leakage and maximum quantum yield data, it was evident that ‘IT185735’ demonstrated poorer growth compared with ‘IT262109’ and ‘IT279432’. Consequently, ‘IT262109’ and ‘IT279432’ show great potential as parent varieties for enhancing salt tolerance in Pak Choi. Full article

In the agricultural industry, the post-harvest leafy vegetable quality and shelf life significantly influence market value and consumer acceptability. This study examined the effects of different storage temperatures on leaf senescence, nitrogen assimilation, and remobilization in Pak Choi (Brassica rapa subsp. chinensis). Mature Pak Choi plants were harvested and stored at two different temperatures, 4 °C and 25 °C. Senescence was tracked via chlorophyll content and leaf yellowing. Concurrently, alterations in the total nitrogen, nitrate, and protein content were quantified on days 0, 3, 6, and 9 in old, mid, and young leaves of Pak Choi plants. As expected, 4 °C alleviated chlorophyll degradation and delayed senescence of Pak Choi compared to 25 °C. Total nitrogen and protein contents were inversely correlated, while the nitrate content remained nearly constant across leaf groups at 25 °C. Additionally, the transcript levels of genes involved in nitrogen assimilation and remobilization revealed key candidate genes that were differentially expressed between 4 °C and 25 °C, which might be targeted to extend the shelf life of the leafy vegetables. Thus, this study provides pivotal insights into the molecular and physiological responses of Pak Choi to post-harvest storage conditions. Full article

Agricultural Jiaosu (AJ) is a method of recycling agricultural wastes for improving soil properties, promoting plant growth, and enhancing plant stress resistance. However, the underlying mechanism by which AJ improves plant stress resistance needs to be determined. Therefore, in this study, two treatments of AJ spraying and water spraying were set up to determine the enzyme activities related to the stress resistance of pak choi after 30 days of growth, and the potential mechanism of AJ’s influence on the stress resistance of pak choi was revealed by transcriptome, metabolome, and rhizome microbiome analyses. Microbial community analysis revealed that the application of AJ does not alter microbial abundance in the rhizosphere; however, it can improve microbial diversity and enrich Actinobacteriota, Proteobacteria, and Firmicutes in the pak choi rhizosphere. Metabolomic analysis revealed that these phyla were significantly positively correlated, with highly upregulated metabolites. Our findings suggest that AJ recruits beneficial microorganisms (BMs) in the rhizosphere and stimulates the expression of genes and metabolites involved in phenylpropanoid and glucosinolate biosynthesis, as well as glutathione and alpha-linolenic acid metabolism pathways. The use of AJ could considerably minimise the use of pesticides and fertilisers and improve the quality of the ecological environment. Full article

Excessive oxidative stress and inflammatory responses are associated with the development of various diseases, including cancer. Glucosinolates (GSLs) are phytochemicals known for their antioxidant properties, and doubled haploid lines (DHLs) of Brassica rapa with high GSL contents (HGSL) were intentionally developed from two edible subspecies of Brassica rapa: B. rapa subsp. trilocularis and B. rapa subsp. chinensis. The purpose of the present study is to assess the capacity of HGSL DHLs to mitigate oxidative stress and inflammation in lipopolysaccharide (LPS)-stimulated RAW264.7 cells, compared to pak choi as a parental control. Our findings demonstrate that HGSL DH lines effectively suppressed the expression of inducible nitric oxide synthase, leading to the reduced levels of nitric oxide at non-toxic concentrations. Additionally, these lines exhibited scavenging activity against reactive oxygen species and free radicals. The enhanced antioxidant capacity of HGSL DHLs was mechanistically attributed to the upregulation of antioxidant enzymes, such as NADPH quinone oxidoreductase 1 (NQO1), the glutamate–cysteine ligase catalytic subunit (GCLC), and heme oxygenase-1 (HMOX1). Furthermore, we confirmed that these effects were mediated through the nuclear factor erythroid 2-related factor 2 (NRF2) signaling pathway via p38 phosphorylation. Moreover, HGSL DHLs demonstrated inhibitory effects on pro-inflammatory cytokines and signal transducers and activators of transcription 3 (STAT3) phosphorylation. Collectively, our results indicate that HGSL DHLs possess better antioxidant and anti-inflammatory properties compared to the parental control pak choi in LPS-stimulated RAW264.7 cells, suggesting that HGSL DHLs of Brassica rapa could be considered as a beneficial daily vegetable for reducing the risk of inflammation-associated diseases. Full article

The aim of this study was to analyze glucosinolates (GSLs) in germplasm that are currently conserved at the RDA-Genebank. The analysis focused on the glucosinolate diversity among the analyzed germplasms, with the goal of identifying those that would be most useful for future breeding efforts to produce nutritionally rich Choy sum plants. In total, 23 accessions of Choy sums that possessed ample background passport information were selected. On analyzing the glucosinolate content for 17 different glucosinolates, we observed aliphatic GSLs to be the most common (89.45%) and aromatic GSLs to be the least common (6.94%) of the total glucosinolates detected. Among the highly represented aliphatic GSLs, gluconapin and glucobrassicanapin were found to contribute the most (>20%), and sinalbin, glucoraphanin, glucoraphasatin, and glucoiberin were detected the least (less than 0.05%). We identified one of the accessions, IT228140, to synthesize high quantities of glucobrassicanapin and progoitrin, which have been reported to contain several therapeutic applications. These conserved germplasms are potential bioresources for breeders, and the availability of information, including therapeutically important glucosinolate content, can help produce plant varieties that can naturally impact public health. Full article