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Chinese cabbage is an important vegetable from both a nutritional and an economic standpoint, with the leafy head serving as the primary harvested organ. However, the nutrient accumulation as well as influencing factors within the leafy head have not yet been elucidated. Thus, the distribution of metabolites (soluble sugars, minerals, carotenoids, vitamin C, flavonoid compounds, glucosinolates, and total phenolic compounds) were investigated in different leaf layers of Chinese cabbage with varying head types. The results showed that the inner leaves consistently displayed markedly higher levels of fructose and glucose when contrasted with the outer leaves. Similarly, there was an accumulation of glucosinolates in the inner leaves. By contrast, however, the antioxidants content exhibited a consistent decline from the outer leaves towards the central core, in line with the diminishing antioxidant capacity. This descending trend was also apparent in the mineral content, encompassing calcium, sodium, magnesium and sulfur. These results will provide dietary instruction, especially for consumers who have particular dietary needs. [ABSTRACT FROM AUTHOR]

Chinese cabbage (Brassica rapa L. ssp. pekinensis) is an important food crop. However, its growth and development are commonly impacted by black spot disease. To examine the response mechanisms of Chinese cabbage to black spot disease, transcriptome and metabolome sequencing were performed on the leaves of Chinese cabbage genotypes J405 (resistant) and B214 (susceptible), 48 h post-infection (hpi) with Alternaria brassicicola. Expression of essential genes in the jasmonic acid, cytokinin, and auxin signaling pathways of both Chinese cabbage genotypes was inhibited. The expression of the pathogenesis-related protein 1 (PR1) gene mediated by the salicylic acid pathway is inhibited in the Chinese cabbage genotype B214. The basic endochitase B (CHIB) gene in the ethylene pathway of both Chinese cabbage genotypes was upregulated. The accumulation of reactive oxygen species in the disease spots of Chinese cabbage genotype J405 was greater than in genotype B214. The respiratory burst oxidase (RBOH) gene in the reactive oxygen species metabolic pathway was significantly upregulated in genotype J405, while no change was observed in genotype B214. We found that oxidation-reduction-related genes such as type-2 peroxiredoxin genes, NADPH-dependent thioredoxin reductase genes, glutathione peroxidase genes, and glutathione S-transfer genes were differentially expressed across both Chinese cabbage genotypes at 48 hpi. Metabolomics demonstrated that delta-tocopherol and S-hexyl glutathione were all downregulated in genotype J405, while they were upregulated in genotype B214. This approach also identified differential expression of genes in the carotenoid biosynthesis pathway, the glycinebetaine biosynthesis pathway, as well as in the specific sulfur glycoside metabolism pathway. These findings indicate that ethylene signaling is important in the hormone signaling regulatory network-mediated disease resistance and defense in Chinese cabbage. When facing pathogen infection, hormone transduction pathways associated with growth and development in Chinese cabbage are inhibited. The accumulation of reactive oxygen species and the outbreak of various secondary metabolites may endow the Chinese cabbage genotype J405 with increased resistance to black spot disease. [ABSTRACT FROM AUTHOR]

Considering that the presence of a leafy head is a key morphological characteristic that determines the yield and quality of Chinese cabbage, identifying the major genes regulating the formation of a leafy head is crucial for variety improvement. A heading-related gene, BrKS, was previously predicted from a non-heading mutant, nhm1, derived from a heading variety, which encodes a key enzyme involved in gibberellin biosynthesis. Here, another mutant, nhm2, was identified from the same EMS-mutagenized population, and the phenotype of nhm2 was consistent with that of nhm1. We crossed mutants nhm1 and nhm2, and their F1 plants exhibited the mutant phenotype, which indicated that their mutant genes were allelic. A single non-synonymous mutation in the fourth exon of BrKS in mutant nhm1 and another single non-synonymous mutation in the tenth exon of BrKS in mutant nhm2. The same gene mutation in mutants nhm1 and nhm2 produced a similar non-heading phenotype, which confirmed the role of BrKS in the leafy head formation of Chinese cabbage. RNA-Seq analysis indicated that a transcription factor gene, BrERF1A, which is associated with leaf development, significantly down-regulated expression in mutant nhm1, and after the mutant was treated with GA3, the expression level of BrERF1A was recovered, which indicated that BrKS might be involved in leafy head formation through regulating the expression level of BrERF1A. Our findings provide important clues for revealing the molecular mechanism of leafy head formation in Chinese cabbage. [ABSTRACT FROM AUTHOR]

Climate change exacerbates drought, globally impacting crop production and necessitating the adoption of sustainable strategies. This study investigates the potential synergistic effects of salicylic acid (SA) and Bacillus butanolivorans KJ40 (KJ40) on napa cabbage (Brassica rapa subsp. pekinensis) under water-deficit stress conditions by watering withheld for five days. Results demonstrate that the combined application of KJ40 and SA, particularly at concentrations of 0.5 mM and 1 mM, significantly enhances plant growth and mitigates the negative impacts of water deficit. Moreover, the combination treatment with SA (0.5 mM) and KJ40 (1 × 108 cells/mL) reduces lipid oxidation and enhances antioxidant enzyme activity, indicating improved plant stress tolerance. Analysis of soil microbial profiles reveals alterations in metabolic activity and substrate utilization patterns, suggesting potential changes in rhizosphere dynamics. Additionally, this study examines the impact of SA on KJ40 population dynamics in soil, revealing concentration-dependent effects on bacterial survival. Overall, the combination of KJ40 and SA was effective in mitigating water-deficit stress in napa cabbage. These findings highlight the combination as a novel synergistic strategy to enhance plant resilience to water-deficit stress, offering insights into plant–microbe interactions and soil ecosystem dynamics. [ABSTRACT FROM AUTHOR]

Leaves are the predominant photosynthetic and edible organs in non-heading Chinese cabbage (Brassica campestris ssp. chinensis, NHCC), contributing significantly to yield, appearance, and desirability to consumers. However, the genetic basis of leaf shape and size in non-heading Chinese cabbage remains unclear. In this study, we developed a RIL population using 'Maertou', with slender leaves and narrow petioles, and 'Suzhouqing', with oval leaves and wide petioles, to construct a genetic linkage map and detect QTLs. To obtain stable and reliable QTLs, the 11 leaf-related traits, including the leaf length, leaf width, and fresh weight of the lamina and petiole and the thickness of petiole was observed on two locations—while the leaf shape, petiole shape, index of lamina/petiole length, and index of petiole fresh weight were calculated based on 7 leaf-related traits. QTL mapping illustrated that a total of 27 QTLs for leaf-related traits were preliminarily detected. The candidate genes were annotated and several genes involved in leaf development and leaf shape appeared in the overlapping regions of multiple loci, such as KRP2, GRF4, ARGOS, and SAUR9. This study lays the foundation for further exploration of the genetic mechanisms and development of effective molecular markers for leaf shape and size in NHCC. [ABSTRACT FROM AUTHOR]

Chinese flowering cabbage is an important bolting stem vegetable widely grown in southern China, but severe losses caused by soft rot disease are very common in this crop. The MYB transcription factor (TF) family is the largest TF family in plants and plays diverse roles in response to stresses. However, the responses of MYB TFs to biotic stress in Chinese flowering cabbage have not been systematically studied. Herein, 255 R2R3-MYB genes were identified in the genome of Chinese flowering cabbage and classified into 29 subgroups based on phylogenetic comparisons with Arabidopsis thaliana. Gene duplication events involved 182 gene duplication pairs, and we found that two tandem duplication events involving R2R3-MYB genes in Chinese flowering cabbage may also affect gene family expansion. Transcriptome data analysis indicated that MYB TF genes are highly enriched in differentially expressed gene (DEG) sets. Combined with phylogenetic and transcriptome analysis, we identified 12 R2R3-MYB genes that potentially play a role in the response to soft rot stress. Our research provides a foundation for further research on the response of R2R3-MYB genes to soft rot stress in Chinese flowering cabbage. [ABSTRACT FROM AUTHOR]

Brassinosteroids (BRs) play critical roles in plant growth by promoting cell elongation and division, leading to increased leaf inclination angles. BRASSINAZOLE RESISTANT 1 (BZR1) and BRI1-EMS-SUPPRESSOR 1 (BES1) act as transcription factors in the brassinosteroid signaling pathway and are involved in several physiological activities regulated by BRs. In this study, we identified and cloned BcBZR1 from the heitacai non-heading Chinese cabbage (NHCC) cultivar. The sequence analysis showed that the coding sequence length of BcBZR1 is 996 bp, encoding 331 amino acid residues. Subcellular localization assays showed that BcBZR1 is localized in the nucleus and cytoplasm and that BcBZR1 protein is transported to the nucleus after receiving BR signals. Compared with Col-0, the leaf inclination angle was smaller in BcBZR1-OX. The EBR treatment experiment indicated that BRs regulate the differential expression of paclobutrazol resistance1 (PRE1) and ILI1 binding bHLH1 (IBH1) in the adaxial and abaxial cells of the petiole through BZR1, thus regulating the leaf inclination angle. The bimolecular fluorescence complementation (BiFC) assay indicated that BcBZR1 interacts with C-repeat Binding Factor2 (BcCBF2) and CBF3. Taken together, our findings not only validate the function of BcBZR1 in leaf inclination angle distribution in non-heading Chinese cabbage, but also contribute to the mechanism of leaf inclination angle regulation in this species under cold stress. [ABSTRACT FROM AUTHOR]

The purple-leaf phenotype in pak choi is due to the accumulation of anthocyanin. The main regulated genes are unclear. The gene controlling the purple-leaf phenotype was mapped on A03 using BSA-seq, but the candidate interval was not further narrowed with InDel markers. Based on our previous study, we hypothesized that the candidate gene that regulates purple leaves in pak choi may also be the Dark_Pur gene from B. juncea. Using the Dark_Pur-1 marker to identify P1, P2, F1, and F2, it was confirmed that the purple trait in purple-leaf pak choi was controlled by the Dark_Pur gene from B. juncea through distant hybridization. A DNA segment of approximately 514 Kb containing the Dark_Pur gene was reintroduced into pak choi from B. juncea. Meanwhile, a new purple pak choi germplasm line was created with green pak choi × purple B. juncea via distant hybridization, which proved that distant hybridization is an effective method for creating new germplasms. Furthermore, the purple-leaf phenotypes of 20 pak choi varieties were identified, and the purple-leaf traits of all lines were derived from B. juncea via distant hybridization. At present, few studies have focused on the background of the purple trait in pak choi; however, in this study, our results suggest that there is a high probability that the purple trait in pak choi may be completely derived from purple B. juncea via distant hybridization. This study also lays a good foundation for research on the creation of new germplasms through distant hybridization among the Brassica species. [ABSTRACT FROM AUTHOR]

Sapium sebiferum is a tree with socioeconomic, environmental, and medicinal value. S. sebiferum seeds possess physiological dormancy, which is induced by endogenous inhibitors and can be broken by cold stratification. However, the putative spatiotemporal changes in inhibitor activity are currently unknown, which can hinder the propagation of S. sebiferum seeds. The objective of this study was to investigate the spatiotemporal dynamics of inhibitor activity and its effect on germination during the cold stratification of S. sebiferum seeds. An extractant consisting of 80% methanol was used to extract the inhibitory substance from the seed coat and endosperm at different stages of cold stratification. The extract was then applied to both the Chinese cabbage seeds and excised embryos of S. sebiferum. The germination percentage and germination index were used to assess the inhibitor activity of S. sebiferum seeds. The germination of non-stratified S. sebiferum seeds was completely inhibited (0% germination). As the stratification duration was extended, the germination percentage of S. sebiferum seeds gradually increased. However, dormancy persisted until the stratification duration reached 120 d; at this point, the mean germination was 81.3%. The germination test on Chinese cabbage seeds revealed a significant increase from 10.0% (stratified for 0 d) to 91.2% (stratified for 120 d) when treated with endosperm extracts. The germination indexes also increased from 0.0 to 40.3, indicating a decrease in the inhibitory activity of endosperm extracts. The seed coat extracting solution showed varying dynamic changes. The lowest germination was observed after 60 d of stratification, with no significant differences among the results of 0 d, 30 d, and 60 d. However, after stratification for 90 d, the germination percentage of Chinese cabbage seeds increased. The germination percentage of excised embryos exhibited similar changes to those of Chinese cabbage seeds. This study discovered that endogenous inhibitors were present in both the seed coat and endosperm of S. sebiferum seeds, and the inhibitor activity was higher in the endosperm. The spatiotemporal patterns of inhibitor activity suggest that the endogenous inhibitors move from the endosperm to the seed coat during early cold stratification stages, aiding in the physiological dormancy release of S. sebiferum seeds. These findings enhance our understanding of seed biology in S. sebiferum and will facilitate high-efficiency seed propagation. [ABSTRACT FROM AUTHOR]

Chinese cabbage (Brassica rapa L. ssp. pekinensis) is an important food crop. However, its growth and development are commonly impacted by black spot disease. To examine the response mechanisms of Chinese cabbage to black spot disease, transcriptome and metabolome sequencing were performed on the leaves of Chinese cabbage genotypes J405 (resistant) and B214 (susceptible), 48 h post-infection (hpi) with Alternaria brassicicola. Expression of essential genes in the jasmonic acid, cytokinin, and auxin signaling pathways of both Chinese cabbage genotypes was inhibited. The expression of the pathogenesis-related protein 1 (PR1) gene mediated by the salicylic acid pathway is inhibited in the Chinese cabbage genotype B214. The basic endochitase B (CHIB) gene in the ethylene pathway of both Chinese cabbage genotypes was upregulated. The accumulation of reactive oxygen species in the disease spots of Chinese cabbage genotype J405 was greater than in genotype B214. The respiratory burst oxidase (RBOH) gene in the reactive oxygen species metabolic pathway was significantly upregulated in genotype J405, while no change was observed in genotype B214. We found that oxidation-reduction-related genes such as type-2 peroxiredoxin genes, NADPH-dependent thioredoxin reductase genes, glutathione peroxidase genes, and glutathione S-transfer genes were differentially expressed across both Chinese cabbage genotypes at 48 hpi. Metabolomics demonstrated that delta-tocopherol and S-hexyl glutathione were all downregulated in genotype J405, while they were upregulated in genotype B214. This approach also identified differential expression of genes in the carotenoid biosynthesis pathway, the glycinebetaine biosynthesis pathway, as well as in the specific sulfur glycoside metabolism pathway. These findings indicate that ethylene signaling is important in the hormone signaling regulatory network-mediated disease resistance and defense in Chinese cabbage. When facing pathogen infection, hormone transduction pathways associated with growth and development in Chinese cabbage are inhibited. The accumulation of reactive oxygen species and the outbreak of various secondary metabolites may endow the Chinese cabbage genotype J405 with increased resistance to black spot disease.

Non-heading Chinese cabbage (cabbage) is an essential green leafy vegetable, and bolting and flowering are necessary for reproduction. However, further research is needed to study the effect of photoperiod on the bolting and flowering of cabbage, particularly on the development of the stem. In this study, we performed phenotypic analysis and measured endogenous gibberellin levels in the cabbage. We carried out these experiments under four different photoperiodic treatments, 12 h (light)/12 h (dark), 14 h (light)/10 h (dark), 16 h (light)/8 h (dark), and 18 h (light)/6 h (dark). The results showed that the time of bolting and flowering gradually decreased with increasing light duration. The development of stems was optimal under the 16 h (light)/8 h (dark) photoperiod treatment, and the same result was obtained via cytological observation. In addition, the changes in the endogenous gibberellin3 (GA3) content under different photoperiodic treatments were consistent with the development of stems and peaked at 16 h (light)/8 h (dark). At the same time, qRT-PCR analysis showed that the relative expression of the key gibberellin synthase genes, BcGA3ox2 and BcGA20ox2, exhibited upregulation. When treated with exogenous GA3 and its synthesis inhibitor, paclobutrazol (PAC), exogenous gibberellins significantly promoted bolting; conversely, gibberellin inhibitors suppressed the bolting, flowering, and stem elongation of cabbage. Therefore, the photoperiod may regulate cabbage bolting by regulating endogenous GA3. [ABSTRACT FROM AUTHOR]

Currently, facility cultivation produces almost a third of all vegetables in China. The intensive production style has led to serious soil problems that need to be tackled. In this paper, a pot experiment was set up to evaluate the effects of optimized fertilization on vegetable growth and soil properties. Specifically, calcium, magnesium, boron and molybdenum were added on the basis of soil testing. The results showed that the growth of Chinese cabbage was significantly increased by optimized fertilization. The soil pH increased (by 3.82%), and EC decreased (by 8.54%). The abundance of culturable bacteria increased by 33.86%, whereas that of fungi decreased by 70.7%. The optimized fertilization increased the richness but not the evenness of soil microorganisms, increased the relative abundance of Proteobacteria, Firmicutes, Bacillus and Bacteroidetes, and decreased the relative abundance of Actinobacteria, Chloroflexi, and superphyla. Optimized fertilization inhibited the growth of Chytridiomycota and Mortierellomycota, especially the plant pathogen Fusarium. Moreover, balanced fertilization was beneficial in promoting various metabolic processes of soil bacteria. Soil water-soluble Ca, Mg, and available Mo might be the main factors driving the change in microbial groups. [ABSTRACT FROM AUTHOR]

In recent times, there has been an increasing demand for the development of rapid and non-destructive assessment of the growth and quality of seedlings before transplanting. This study was conducted to examine the growth and quality of Chinese cabbage seedlings that can be determined via the image data acquired using a multispectral camera. Chinese cabbage seedlings were cultivated in five different plug trays (72, 105, 128, 162, and 200 cells/tray) for 30 days after sowing (DAS). The growth of seedlings had no significant difference in the early stage of cultivation; however, it decreased with increasing the number of cells in the plug tray due to the restricted root zone volume in the mid to late stages. Individual leaf area was predicted by analyzing of image data with high accuracy (R2 > 0.8) after 15 DAS; however, the accuracy of leaf area prediction per tray decreased due to overlapping and twisting leaves. Among six different vegetation indices, mrNDVI showed a high correlation (R2 > 0.6) with the dry weight of seedlings at 25 and 30 DAS. We confirmed that the leaf area of seedlings can be predicted non-destructively by analyzing the acquired image data per seedling and tray and suggested the applicability of vegetation indices for predicting the growth and quality of vegetable seedlings. [ABSTRACT FROM AUTHOR]

In order to make the identification and utilization of nutritional quality components in Chinese cabbage more predictive, to obtain ideal raw materials, and to help screen functional Chinese cabbage varieties that have high nutritional value, we conducted a comprehensive evaluation of the nutritional quality of different Chinese cabbage varieties. In this study, 17 nutritional quality indexes of 35 Chinese cabbage varieties, including crude fiber (CF), crude protein (CP), vitamin C (VC), glucose (Glc), fructose (Fru), malic acid (MA), citric acid (CA), oxalic acid (OA), total amino acid (TAA) and CA, K, Mg, P, Cu, Fe, Mn and Zn, were analyzed using diversity analysis, correlation analysis, principal component analysis, membership function analysis and cluster analysis. The results showed that there were different degrees of variation in the 17 nutritional quality indexes, and the coefficients of variation ranged from 11.45% to 91.47%. The correlation analysis found that there were significant or extremely significant correlations between different nutrient elements of Chinese cabbage, which indicated that principal component analysis could be carried out, and the comprehensive score (D value) of different materials could be obtained using principal component analysis and the membership function method. The nutritional quality of Chinese cabbage was classified into five grades by cluster analysis. Finally, a mathematical model for evaluating the nutritional quality of Chinese cabbage was established using the D value and multiple stepwise regression methods, and 10 key indexes were selected from the 17 indexes, which could be used for the rapid identification of the nutritional quality of Chinese cabbage. This study provided a theoretical basis for the nutritional quality evaluation and variety breeding of Chinese cabbage. [ABSTRACT FROM AUTHOR]

This document, titled "Morphology, Palynology and Phytochemicals of Medicinal Plants," discusses the importance of studying plant morphology, palynology, and phytochemicals in understanding the medicinal properties of plants. The Special Issue focuses on investigating new phytochemicals, changes in morphology and palynology across various plant families, and utilizing traditional and sophisticated techniques for plant identification and analysis. It emphasizes the potential of plants as sources of new medications and therapies, highlighting the wide variety of phytochemicals they contain. The document also emphasizes the relevance of integrative techniques in botanical research and the significance of biodiversity for medical research. The Special Issue features 15 research articles and one review article that explore the structural, genetic, and chemical diversity of medicinal plants. [Extracted from the article]

Considering that the presence of a leafy head is a key morphological characteristic that determines the yield and quality of Chinese cabbage, identifying the major genes regulating the formation of a leafy head is crucial for variety improvement. A heading-related gene, BrKS, was previously predicted from a non-heading mutant, nhm1, derived from a heading variety, which encodes a key enzyme involved in gibberellin biosynthesis. Here, another mutant, nhm2, was identified from the same EMS-mutagenized population, and the phenotype of nhm2 was consistent with that of nhm1. We crossed mutants nhm1 and nhm2, and their F1 plants exhibited the mutant phenotype, which indicated that their mutant genes were allelic. A single non-synonymous mutation in the fourth exon of BrKS in mutant nhm1 and another single non-synonymous mutation in the tenth exon of BrKS in mutant nhm2. The same gene mutation in mutants nhm1 and nhm2 produced a similar non-heading phenotype, which confirmed the role of BrKS in the leafy head formation of Chinese cabbage. RNA-Seq analysis indicated that a transcription factor gene, BrERF1A, which is associated with leaf development, significantly down-regulated expression in mutant nhm1, and after the mutant was treated with GA3, the expression level of BrERF1A was recovered, which indicated that BrKS might be involved in leafy head formation through regulating the expression level of BrERF1A. Our findings provide important clues for revealing the molecular mechanism of leafy head formation in Chinese cabbage.

Chinese cabbage is a popular leaf vegetable, and many cultivars have been developed for different regions and growing seasons. For the identification of the cultivars, many marker systems have been applied, but they usually require a large number of markers and expensive equipment. Therefore, it is necessary to develop an efficient and economical method for identifying Chinese cabbage cultivars. In this study, we aimed to develop a marker system with the minimum number of markers using simple PCR and gel electrophoresis. A total of 48 simple sequence repeats (SSRs) in a previous study were screened based on their chromosomal location and applied to 105 Chinese cabbage cultivars. The minimum number of markers was selected based on their genomic location, polymorphic information content, and allele frequency. To validate the cultivar identification capability of selected SSRs, they were applied to genetically similar cultivar pairs from a previous study. Eleven SSRs were finally selected, and they successfully identified cultivars with high genetic similarity, as well as all 105 Chinese cabbage cultivars tested. The proposed SSRs require only 11 primer sets, simple PCR, and gel electrophoresis, which need less time and resources compared to previous ones. These SSRs can be used not only in small seed companies and laboratories but also in large-scale seed companies. [ABSTRACT FROM AUTHOR]

Determining plant responses to hazardous air pollutants is critical in predicting food security programs and challenges in the future. This study aimed to determine the effects of various ozone levels on plant growth responses (leaf area, dry matter, and number of leaves) and biochemical quality (photopigments and glucosinolates) on Brassica campestris L. ssp. chinensis (Pak-Choi). The experiment was conducted within test chambers under different ozone concentrations (60, 150, and 240 ppb for 2 h/day). Leaf area and dry matter were negatively correlated with increasing ozone concentrations, but the number of leaves was not affected by ozone treatment. Lycopene and chlorophylls also showed the same tendency. Even if the ambient ozone concentration was only elevated for a short time, various glucosnilates (GLS) have been diversely affected. The total aliphatic GLS content was reduced. In contrast, the total indole GLS increased at the highest ozone concentration, and the aromatic GLS significantly increased and then decreased as the ozone concentration level increased. These results provide evidence of the strong effect of ozone stress on the plant quality of Pak-Choi with respect to certain secondary plant metabolites. These findings provide an understanding of elevated ozone effects in urban horticulture sites on the growth and metabolite profiling of Brassica plants. [ABSTRACT FROM AUTHOR]

Elaborating on the methods and means of enriching nutrition, including that of plants, with a number of microelements that are vital for humans is now very important due to the unresolved acute problems of micronutrient deficiency and imbalance, which affect the majority of the population of various countries in the world. Promising solutions for the implementation of biofortification in terms of safety, efficiency, size, biocompatibility, and transportability are the water-soluble derivatives of C60 or C70 fullerene. By now, the use of water-soluble fullerenes (C60(OH)22–24 or C70(OH)12–14 fullerenols, C60 fullerene with glycine or with arginine: C60-L-Gly or C60-L-Arg) with various functional groups for plant enrichment is pioneering. Experimental research work was carried out at the agrobiopolygon of the Agrophysical Research Institute under controlled microclimate conditions. This work constituted an assessment of the influence of C60(OH)22–24 fullerenol introduction into the soil on the content of macro- and microelements in the soil and in plants, for example, cucumber, as well as on the plants' physiological state (photosynthetic pigments, the intensity of lipid peroxidation, the activity of peroxidase and catalase enzymes), growth, and element content. Its aim was to study the possibility of enriching the plants' production (Chinese cabbage, tomato, and cucumber) with compositions of the fullerene derivatives (C60-L-Gly or C60-L-Arg, C60(OH)22–24 or C70(OH)12–14 fullerenols) and selenium or zinc compounds by introducing them into a nutrient solution or by foliar treatment of plants. It was revealed that the introduction of solutions of C60 fullerenol in various concentrations (1 mg/kg, 10 mg/kg, and 100 mg/kg) into soddy-podzolic sandy loamy soil contributed to the activation of the processes of nitrogen transformation in the soil, in particular, the enhancement of the process of nitrification, and to the increase in the content of mobile forms of some macro- and microelements in the soil as well as of the latter in plant organs, for example, in cucumber plants, especially in their leaves. Along with this, the plants showed an increase in the content of photosynthetic pigments, a predominant decrease in the activity of the oxidative enzyme peroxidase and in the intensity of lipid peroxidation, and an increase in the content of the reducing enzyme catalase. The improvement in the physiological state of plants had a positive effect on the growth rates of cucumber plants. The compositions of solutions of amino acid fullerenes (C60-L-Gly or C60-L-Arg) and sodium selenate as well as C60 or C70 fullerenols and zinc sulfate, selected on the basis of different charges of molecules or functional groups of fullerene derivatives, showed higher efficiency at low concentrations in enriching the plant products of Chinese cabbage, tomato, and cucumber with selenium and zinc, respectively, compared with mineral salts of the indicated elements and control (edible part of Chinese cabbage: by 31.0−89.0% relative to that in the control and by 26.0–81.0% relative to the treatment of plants with a sodium selenate; tomato fruits: by 33.7–42.2% relative to that in the control and by 10.2–17.2% relative to the treatment of plants with a sodium selenate; cucumber fruits: by 42.0–59.0% relative to that in the control and by 10.0–23.0% relative to the treatment of plants with a zinc sulfate). At the same time, the quantitative characteristics of growth, productivity, and/or quality of the obtained products increase and improve accordingly. The prospects for further research include an in-depth study into the mechanisms of the compositions of fullerene derivatives and various compounds of trace elements' influence on the plants, as well as the synthesis and study of the various exo- and endo derivatives of fullerenes' properties, including C60 complex compounds with transition metals and fullerenes, which, inside their carbon networks, contain atoms of various chemical elements, such as lanthanum and others. [ABSTRACT FROM AUTHOR]

It is well known that some plants have the capability of taking up sulfur as a nutrient from the atmosphere through foliar absorption and can survive well in polluted environments. In order to observe the effects of the relationship between atmospheric hydrogen sulfide (H2S) deposition and soil sulfur nutrition, the current study used Brassica pekinensis as a model plant. The objective in conducting this study was to understand the regulatory mechanisms engaged in the uptake and assimilation of sulfate (SO42−) in plants by studying the modulation of transcription levels of sulfate transporter genes (STGs) (Sultr1;1 and Sultr1;2), changes in growth physiology, and the potential of roots to uptake the SO42− when allowed to grow in the presence or absence of SO42− in a hydroponic nutrient solution. Changes in growth, physico-chemical parameters, and gene expression levels of Group 1 STGs were observed when sulfur-treated and non-treated plants were exposed to phytotoxic H2S levels in the air. Sulfur deficiency enhanced nitrate and free amino acid (FAA) concentrations in the shoot and root regions of the plant. However, there was a significant decrease in the biomass, shoot/root ratio (SRR), chlorophyll content, and thiol content, with p-values < 0.01. This, in turn, increased the sulfur-uptake capacity of plants from the atmosphere through foliar absorption. When the sulfur-uptake capacity of plants increased, there was an increase in the expression level of Group 1 sulfate transporter genes (Sultr1;1 and Sultr1;2), which regulate sulfur transportation through roots. The growth, physico-chemical characteristics, and level of gene expression of Group 1 STGs were unaffected by the availability of excess sulfur in the atmosphere of up to 0.3 μL l−1. [ABSTRACT FROM AUTHOR]

Affected by global warming, continuous high temperature has a negative impact on plant growth and development and become a major constraint to crop production. Germplasm resource identification has become a research hotspot in many fields, and it is also necessary to establish effective identification methods. In this study, twenty Brassica rapa varieties were selected to investigate the physiological and biochemical characteristics under heat stress, explore the relationship between physiological response and the heat resistance mechanism, and select some typical heat-resistant and heat-sensitive varieties. The effects of photosynthetic electron transfer and antioxidant pathway on the heat resistance of Brassica rapa were identified. These findings will provide important guidance for the physiological regulation and identification method of heat stress in plants. [ABSTRACT FROM AUTHOR]

Clubroot disease caused by Plasmodiophora brassicae Woronin (P. brassicae) has seriously influenced the production of Brassica rapa crops, but the interaction mechanism between P. brassicae and Brassica rapa is not clear. In our previous study, a differentially expressed protein, G15, was found between the roots of Chinese cabbage inoculated and un-inoculated with P. brassicae through two-dimensional electrophoresis (2-DE) and mass spectrometry, and G15 was matched with Bra011464. In this study, Bra011464 was found to have a 94% percent identity with Arabidopsis thaliana CAP, named BrCAP. The expression of BrCAP was the highest in the root compared with the stems and leaves of Chinese cabbage, and its expression in the roots of Chinese cabbage inoculated with P. brassicae was significantly higher than that in the control. The results were verified by real-time quantitative polymerase chain reaction (RT-qPCR) and in situ hybridization. Subcellular localization showed that BrCAP was localized on chloroplasts of leaf epidermal cells. To verify the function of BrCAP, it was found that the Arabidopsis thaliana mutant cap was more susceptible to infection with P. brassicae than the wild type (WT), which suggested that BrCAP has a potential role in the resistance progress of Chinese cabbage to P. brassicae. [ABSTRACT FROM AUTHOR]

The species Brassica rapa includes enormous leafy vegetables with extreme leaf morphological diversity. Leaf traits such as size, shape, weight, and ratio of the leaf blade to the petiole contribute to yield, appearance, and desirability to consumers. These leaf-related traits are controlled by quantitative trait loci (QTLs). The construction of high-density bin maps using low-coverage sequencing is a powerful method for QTL fine-mapping and gene identification. In this study, we performed whole-genome re-sequencing of Wutacai 'Zhongbaye' and Chinese cabbage 'HN53' and 150 F2 individuals to construct a high-density bin map for QTL mapping of 11 leaf-related traits. The parental lines and F2 population were re-sequenced at 10x and 1x coverage, respectively. A map containing 565 bin markers was constructed based on parental single-nucleotide polymorphisms and a modified sliding window approach. The total map length was 944.6 cM and the average distance of the bins was 1.65 cM. In total, 60 significant QTLs controlling 11 leaf-related traits were detected. We further identified candidate genes responsible for these complex leaf-related traits. These findings suggest that this cost-effective bin-mapping approach is capable of rapid identification of QTLs and candidate genes, and will thus facilitate the dissection of the underlying molecular basis of leaf morphological variations and accelerate the improvement of B. rapa vegetable breeding. [ABSTRACT FROM AUTHOR]

The nutritional quality and biomass of various sprouts can be enhanced by Zn and red-blue light, especially the Brassica sprouts. However, the combined effects of this two on sprouts are rarely reported. In this study, different Zn concentrations (0, 1.74, 3.48, 10.43 and 17.39 mM) were combined with two ratios of red-blue light-emitting diodes (LEDs) (R: B = 1:2, 1R2B; R: B = 2:1, 2R1B, at 70 μmol m−2 s−1 PPFD, 14 h/10 h, light/dark) to investigate their mutual effects on the growth, mineral elements, and nutritional quality in flowering Chinese cabbage sprouts (FCCS). Fresh weight, dry weight, contents of organic Zn, soluble sugar, vitamin C, total flavonoids, total polyphenol, FRAP (ferric ion-reducing antioxidant power) and DPPH (radical inhibition percentage of 1,1-diphenyl-2-picrylhydrazyl) were significantly increased by Zn supplement (10.43 and 17.39 mM) and 2R1B, while hypocotyl length and moisture content were decreased remarkably by Zn supplement. Total glucosinolates contents in the sprouts increased dramatically under 2R1B compared with 1R2B, while photosynthetic pigments contents decreased. Heat map and principal component analysis showed that 2R1B + 17.39 mM Zn was the optimal treatment for the accumulation of biomass and health-promoting compound in FCCS, suggesting that a suitable combination of light quality and Zn supplement might be beneficial to zinc-biofortified FCCS production. [ABSTRACT FROM AUTHOR]

Purple heading Chinese cabbage has become popular in recent years due to its attractive color and health benefits. However, purple varieties remain rare, and the regulation mechanism of anthocyanin accumulation in Chinese cabbage is still largely unknown. By introducing the purple color trait from Brassica juncea, a new purple heading Chinese cabbage cultivar (18M-245) was generated with deep purple leaves at both the seedling and adult stages. Anthocyanin accumulation in 18M-245 increased when grown at low temperatures. FISH and genotyping results showed that the purple trait was caused by an alien chromosome addition line derived from the Brassica B genome. The LDOX coding gene BjuB014115 from the addition line was highly expressed in 18M-245, consistent with the results of anthocyanin accumulation. Meanwhile, several MYB and bHLH transcriptional factors from the Brassica A genome were found to directly bind to the promoter of BjuB014115, suggesting that interactions between the Brassica A and B genomes are involved in the regulatory network of anthocyanin biosynthesis in Chinese cabbage. Our results provide new insights into the regulation mechanism of anthocyanin biosynthesis in purple heading Chinese cabbage. [ABSTRACT FROM AUTHOR]

Currently, facility cultivation produces almost a third of all vegetables in China. The intensive production style has led to serious soil problems that need to be tackled. In this paper, a pot experiment was set up to evaluate the effects of optimized fertilization on vegetable growth and soil properties. Specifically, calcium, magnesium, boron and molybdenum were added on the basis of soil testing. The results showed that the growth of Chinese cabbage was significantly increased by optimized fertilization. The soil pH increased (by 3.82%), and EC decreased (by 8.54%). The abundance of culturable bacteria increased by 33.86%, whereas that of fungi decreased by 70.7%. The optimized fertilization increased the richness but not the evenness of soil microorganisms, increased the relative abundance of Proteobacteria, Firmicutes, Bacillus and Bacteroidetes, and decreased the relative abundance of Actinobacteria, Chloroflexi, and superphyla. Optimized fertilization inhibited the growth of Chytridiomycota and Mortierellomycota, especially the plant pathogen Fusarium. Moreover, balanced fertilization was beneficial in promoting various metabolic processes of soil bacteria. Soil water-soluble Ca, Mg, and available Mo might be the main factors driving the change in microbial groups.

In order to make the identification and utilization of nutritional quality components in Chinese cabbage more predictive, to obtain ideal raw materials, and to help screen functional Chinese cabbage varieties that have high nutritional value, we conducted a comprehensive evaluation of the nutritional quality of different Chinese cabbage varieties. In this study, 17 nutritional quality indexes of 35 Chinese cabbage varieties, including crude fiber (CF), crude protein (CP), vitamin C (VC), glucose (Glc), fructose (Fru), malic acid (MA), citric acid (CA), oxalic acid (OA), total amino acid (TAA) and CA, K, Mg, P, Cu, Fe, Mn and Zn, were analyzed using diversity analysis, correlation analysis, principal component analysis, membership function analysis and cluster analysis. The results showed that there were different degrees of variation in the 17 nutritional quality indexes, and the coefficients of variation ranged from 11.45% to 91.47%. The correlation analysis found that there were significant or extremely significant correlations between different nutrient elements of Chinese cabbage, which indicated that principal component analysis could be carried out, and the comprehensive score (D value) of different materials could be obtained using principal component analysis and the membership function method. The nutritional quality of Chinese cabbage was classified into five grades by cluster analysis. Finally, a mathematical model for evaluating the nutritional quality of Chinese cabbage was established using the D value and multiple stepwise regression methods, and 10 key indexes were selected from the 17 indexes, which could be used for the rapid identification of the nutritional quality of Chinese cabbage. This study provided a theoretical basis for the nutritional quality evaluation and variety breeding of Chinese cabbage.

Nitrogen (N) is a major limiting factor for plant growth and vegetable production. Understanding the regulatory mechanisms of N uptake, transport, and assimilation is key to improving N use efficiency in plants. Ammonium transporters (AMTs) play an important role in plant N metabolism. In this study, we isolated an important AMT1 subfamily member (BcAMT1;5) with a highly conserved signatural AMT1 subfamily motif from flowering Chinese cabbage. Based on functional complementation in yeast mutant 31019b and overexpression of BcAMT1;5 in Arabidopsis, BcAMT1;5 is a functional AMT. Tissue expression analysis showed that BcAMT1;5 was mainly expressed in roots and showed multiple N regime transcript patterns to respond to varying nutritional conditions. This was up-regulated by N-deficiency and down-regulated by supplying NH4+. The glucuronidase (GUS) activities of BcAMT1;5pro::GUS showed a similar change in response to different N conditions. Overexpression of BcAMT1;5 accelerated the growth of transgenic seedlings, increased NH4+ net influxes, and enhanced the content and accumulation of NH4+ and NO3− at low N concentrations. Additionally, it increased the transcript levels of N assimilation-related genes in shoots. These results indicate that BcAMT1;5 may participate in N uptake and assimilation under various N conditions in flowering Chinese cabbage, but it was differed obviously from other AMT1s. [ABSTRACT FROM AUTHOR]

As an important genetic improvement technique in current production practice, heterosis is widely used to enhance the productive traits of hybrid progeny from their parents. Alternative splicing (AS) analysis can be used as a method for exploring the molecular manifestations of heterosis. In our research, 16 hybrids and their parents were utilized to analyze the heterosis performance and AS events. Statistics of plant gross weight (PGW) showed that these hybrids had prominent heterosis, with the mid-parent heterosis values (MPV) ranging from 15.69% to 233.98%. Through pairwise comparison among the female parent, male parent, and hybrid, there were 2980–3205 AS events in each combination, with intron retention being the most common type followed by alternate 3' splice site, alternative 5' splice site, skipped exon, and mutually exclusive exon.There were 263–409 differential AS genes (DASGs) between the female parent and the hybrid, and 234–425 DASGs between the male parent and the hybrid in cross combinations. The DASGs were significantly enriched in 33 metabolic pathways in 16 cross combinations, and DASGs of different cross combinations were enriched in different metabolic pathways. Moreover, 76 DASGs in the strong heterosis combinations were identified and significantly enriched in the metabolic pathways related to amino acid metabolism. Further analysis revealed that most of these DASGs in amino acid metabolism were expressed differently in strong heterosis combinations. In addition, the expression levels of BraA06g014310.3C and BraA03g041700.3C in amino acid metabolism significantly correlated with PGW. These results could provide an index for future studies of the genetic and molecular mechanism of heterosis in hybrids. [ABSTRACT FROM AUTHOR]

Hydroponics has become a popular production technology for leafy greens in greenhouses. However, year-round production of cool-season leafy greens remains challenging due to costly heating and cooling during winter and summer seasons, depending on location. Therefore, the objective of this study is to investigate the effect of nutrient solution cooling and heating in deep-water hydroponic systems on the performance of several leafy green vegetables. Two experiments of nutrient solution cooling during the summer season and another two experiments of nutrient solution heating during the winter season were conducted in Texas, USA in 2020–2021. Lettuce (Lactuca sativa L.) 'Bergams Green' and 'Red Mist', Pak Choi (Brassica rapa subsp. chinensis) 'Purple Magic' and 'White Stem', and spinach (Spinacia oleracea L.) 'Mandolin' and 'Seaside' were grown in the summer experiments, and only the two lettuce cultivars were grown for the winter experiments. For both cooling and heating studies, six deep-water culture systems were used with two treatments: cooling (23 °C) vs. no cooling, and heating (22 °C) vs. no heating, with three replications in each experiment. In the nutrient solution cooling study, spinach was the most heat-sensitive species, and 'Mandolin' was more heat-tolerant than 'Seaside,' as evidenced by its lower mortality rate in both experiments. Lettuce and pak choi grew well and solution cooling increased shoot fresh weight in both lettuce cultivars and in 'White Stem' pak choi but not in 'Purple Magic' pak choi. Conversely, during the winter season, solution heating increased shoot fresh weight of both lettuce cultivars; however, 'Red Mist' was more responsive than 'Bergams Green' lettuce. These results indicate the potential to increase crop yield by controlling nutrient solution temperature throughout the year, depending on the season. Also, there were genotypic differences in both cooling and heating experiments, indicating that more research is needed to determine the species-dependent and even cultivar-dependent nutrient solution temperature control strategies to achieve optimum year-round production. [ABSTRACT FROM AUTHOR]

Despite the steadily increasing area under protected agriculture there is a current lack of knowledge about the effects of the insect-proof screen (IPS) on microclimate and crop water requirements in arid and semi-arid regions. Field experiments were conducted in two crop cycles in Ningxia of Northwest China to study the impact of IPS on microclimate, reference evapotranspiration (ET0) and growth of Chinese Flowering Cabbage (CFC). The results showed that IPS could appreciably improve the microclimate of the CFC field in the two crop cycles. During the first crop cycle (C1), compared with no insect-proof screen (NIPS) treatment, the total solar radiation and daily wind speed under the IPS treatment were reduced by 5.73% and 88.73%. IPS increased the daily average air humidity, air, and soil temperature during C1 by 11.84%, 15.11% and 10.37%, respectively. Furthermore, the total solar radiation and daily wind speed under the IPS treatment during the second crop cycle (C2) were markedly decreased by 20.45% and 95.73%, respectively. During C2, the daily average air temperature and air humidity under the IPS treatment were increased slightly, whereas the daily average soil temperature was decreased by 4.84%. Compared with NIPS treatment, the ET0 under the IPS treatment during C1 and C2 was decreased by 6.52% and 21.20%, respectively, suggesting it had great water-saving potential when using IPS. The plant height, leaf number and leaf circumference of CFC under the IPS treatment were higher than those under the NIPS treatment. The yield under the IPS treatment was significantly increased by 36.00% and 108.92% in C1 and C2, respectively. Moreover, irrigation water use efficiency (IWUE) was significantly improved under the IPS treatment in the two crop cycles. Therefore, it is concluded that IPS can improve microclimate, reduce ET0, and increase crop yield and IWUE in arid and semi-arid areas of Northwest China. [ABSTRACT FROM AUTHOR]

Drought can seriously hinder the growth of plants, resulting in reduced crop yield and quality. At present, the tolerance of DEAD-box helicases (DHC) to abiotic stresses, such as drought, high salinity, low temperature, and high temperature, has been confirmed in a variety of plants; therefore, using DEAD-box helicases to develop stress-resistant plants has great application prospects. In this study, Brassica rapa was used as a model to explore the response of the BrDHC1 gene to drought stress by creating RNA interference and overexpressing lines in B. rapa. The mechanism of BrDHC1 involved in drought resistance was revealed by the analysis of morphological characteristics, physiological indicators, and expression analysis of related stress response genes. The results showed that the overexpression of the BrDHC1 gene was more conducive to enhancing the resilience of plants under drought stress in B. rapa. Taken together, these results confirmed BrDHC1 as a newly identified DEAD-box helicase gene that could actively regulate plant growth and development under drought stress in B. rapa. [ABSTRACT FROM AUTHOR]

Elaborating on the methods and means of enriching nutrition, including that of plants, with a number of microelements that are vital for humans is now very important due to the unresolved acute problems of micronutrient deficiency and imbalance, which affect the majority of the population of various countries in the world. Promising solutions for the implementation of biofortification in terms of safety, efficiency, size, biocompatibility, and transportability are the water-soluble derivatives of C60 or C70 fullerene. By now, the use of water-soluble fullerenes (C60(OH)22–24 or C70(OH)12–14 fullerenols, C60 fullerene with glycine or with arginine: C60-L-Gly or C60-L-Arg) with various functional groups for plant enrichment is pioneering. Experimental research work was carried out at the agrobiopolygon of the Agrophysical Research Institute under controlled microclimate conditions. This work constituted an assessment of the influence of C60(OH)22–24 fullerenol introduction into the soil on the content of macro- and microelements in the soil and in plants, for example, cucumber, as well as on the plants’ physiological state (photosynthetic pigments, the intensity of lipid peroxidation, the activity of peroxidase and catalase enzymes), growth, and element content. Its aim was to study the possibility of enriching the plants’ production (Chinese cabbage, tomato, and cucumber) with compositions of the fullerene derivatives (C60-L-Gly or C60-L-Arg, C60(OH)22–24 or C70(OH)12–14 fullerenols) and selenium or zinc compounds by introducing them into a nutrient solution or by foliar treatment of plants. It was revealed that the introduction of solutions of C60 fullerenol in various concentrations (1 mg/kg, 10 mg/kg, and 100 mg/kg) into soddy-podzolic sandy loamy soil contributed to the activation of the processes of nitrogen transformation in the soil, in particular, the enhancement of the process of nitrification, and to the increase in the content of mobile forms of some macro- and microelements in the soil as well as of the latter in plant organs, for example, in cucumber plants, especially in their leaves. Along with this, the plants showed an increase in the content of photosynthetic pigments, a predominant decrease in the activity of the oxidative enzyme peroxidase and in the intensity of lipid peroxidation, and an increase in the content of the reducing enzyme catalase. The improvement in the physiological state of plants had a positive effect on the growth rates of cucumber plants. The compositions of solutions of amino acid fullerenes (C60-L-Gly or C60-L-Arg) and sodium selenate as well as C60 or C70 fullerenols and zinc sulfate, selected on the basis of different charges of molecules or functional groups of fullerene derivatives, showed higher efficiency at low concentrations in enriching the plant products of Chinese cabbage, tomato, and cucumber with selenium and zinc, respectively, compared with mineral salts of the indicated elements and control (edible part of Chinese cabbage: by 31.0−89.0% relative to that in the control and by 26.0–81.0% relative to the treatment of plants with a sodium selenate; tomato fruits: by 33.7–42.2% relative to that in the control and by 10.2–17.2% relative to the treatment of plants with a sodium selenate; cucumber fruits: by 42.0–59.0% relative to that in the control and by 10.0–23.0% relative to the treatment of plants with a zinc sulfate). At the same time, the quantitative characteristics of growth, productivity, and/or quality of the obtained products increase and improve accordingly. The prospects for further research include an in-depth study into the mechanisms of the compositions of fullerene derivatives and various compounds of trace elements’ influence on the plants, as well as the synthesis and study of the various exo- and endo derivatives of fullerenes’ properties, including C60 complex compounds with transition metals and fullerenes, which, inside their carbon networks, contain atoms of various chemical elements, such as lanthanum and others.

The turnip and the Chinese cabbage belong to the Brassica rapa subspecies, yet they have evolved marked differences in morphology. The turnip has a distinct swelled taproot, while the Chinese cabbage has a big leafy head. The turnip's taproot is developed mainly by the hypocotyl. To explore the taproot formation, we firstly compared the vascular structure of the hypocotyl during the early developmental stages of the turnip and the Chinese cabbage, finding that there were observable differences in the number of xylem cells and the cell-wall lignification in the hypocotyl vascular tissues after the transition from primary to secondary growth. Laccases (LAC) play an important role in lignification by polymerizing monolignols in the cell wall, however, it is not clear whether differences in the lignification levels in the hypocotyl xylem cell walls are related to the genetic variations of the LAC gene family, between the turnip and the Chinese cabbage. Therefore, we systematically characterized the LAC genes from the turnip and the Chinese cabbage, and 27 LAC genes were identified in each. These LAC genes can be divided into six groups, and each LAC in the turnip is closely adjacent to that in the Chinese cabbage. Gene structure, conserved motif, and chromosomal localization were highly conserved between the turnip and the Chinese cabbage. We also compared the expression pattern of the laccases in the different tissues and hypocotyl's early development stage, and the results clearly showed the different profiles between the turnip and the Chinese cabbage. Following a comprehensive analysis of these results, we predicted that LAC17.1 and LAC17.3 are two candidate genes that participate in the regulation of lignin synthesis during taproot formation. Our results provide a valuable clue for uncovering the regulation mechanism of the lower lignification level in the turnip's hypocotyl and fundamental information for further studies of the LAC gene family in Brassica rapa. [ABSTRACT FROM AUTHOR]

The purpose of this study was to explore the regulation of BcMYB44 on anthocyanin synthesis and drought tolerance of non-heading Chinese cabbage. The BcMYB44 gene was cloned from the purple inbred line 'NJZX1-3' and its green mutant 'NJZX1-0'. Sequence analysis confirmed that BcMYB44 belongs to the R2R3-MYB family and has the highest homology with BnMYB44. Subcellular localization revealed that BcMYB44 is a nuclear protein. Yeast two-hybrid (Y2H) and Bimolecular Fluorescent Complimentary (BiFC) experiments showed that BcMYB44 interacts with BcPAP1 and BcEGL3. Pigment detection of BcPAP1 and BcMYB44 protein activity in N. benthamiana indicates that BcMYB44 plays a negative regulatory role by inhibiting the expression of key structural genes (F3H, DFR, etc.) in anthocyanin synthesis. Virus-induced gene silencing (VIGS) further confirmed this inhibition. Analysis of drought tolerance of non-heading Chinese cabbage based on VIGS showed that pTY-S plants are more resistant to drought than pTY-BcMYB44 plants. The results indicate that BcMYB44 has a positive regulatory role in drought stress, which most likely is achieved by inhibiting anthocyanin accumulation, regulating stomatal movement, and improving osmotic regulation and homeostasis of reactive oxygen species (ROS). [ABSTRACT FROM AUTHOR]

Previous research has shown that miR398 contributed to plant thermotolerance by silencing its target gene COPPER/ZINC SUPEROXIDE DISMUTASE1 (CSD1) in Arabidopsis thaliana. However, the phylogenesis of miR398 and CSD1 in Brassica crop and their role in regulating leaf cell death under heat stress remains unexplored. Here, we characterized the homologous genes of miR398a and CSD1 in Brassica rapa ssp. pekinensis (Chinese cabbage) and found miR398a abundance was accumulated under heat stress (38 °C and 46 °C for 1 h) in Chinese cabbage, while the expression level of its targets BraCSD1-1 and BraCSD2-1 were downregulated. To further explore their role in heat response, we constructed the transgenic plants overexpressing artificial miR398a (aBra-miR398a), Bra-miR398a target mimic (Bra-MIM398a), and BraCSD1-1 in Chinese cabbage for genetic study. Under high temperatures, p35S::aBra-miR398a lines reduced the areas of leaf cell death and delayed the leaf cell death. By contrast, p35S::Bra-MIM398a and p35S::BraCSD1-1 plants enlarged the areas of leaf cell death and displayed the earliness of leaf cell death. Finally, we found that the expression level of stress-responsive genes BraLEA76, BraCaM1, BraPLC, BraDREB2A, and BraP5CS increased in transgenic plants overexpressing aBra-miR398a, which may contribute to their resistance to heat-induced leaf cell death. Taken together, these results revealed the function of Bra-miR398a in attenuating leaf cell death to ensure plant thermotolerance, indicating that the miR398-CSD1 module could be potential candidates for heat-resistant crop breeding. [ABSTRACT FROM AUTHOR]

Mutagenesis is an important tool for breeding and genomic research. In this study, the germinated seeds and isolated microspores of a double haploid line 'FT' were treated with EMS, respectively, with the aim of comparing the effects of the two approaches on generating mutants in Chinese cabbage. For microspore EMS mutagenesis, the isolated microspores were treated with 0.12% EMS for 20 min, a total of 1268 plantlets were obtained, and 15 M1 mutants were screened with a mutation frequency of 1.2%. For seed EMS mutagenesis, 7800 germinated seeds were treated with 0.8% EMS for 12 h, and a total of 701 M2 mutants were screened, with a mutation frequency of 18.78%. In total, 716 mutants with heritable morphological variation including leaf color, leaf shape, leafy head, bolting, and fertility, were obtained from the EMS mutagenesis experiments. Homozygous mutant plants could be screened from M1 lines by microspore mutagenesis, and M2 lines by seed mutagenesis. The mutation frequency was higher in seed mutagenesis than in microspore mutagenesis. Based on these results, we propose that seed EMS mutagenesis is more suitable to generate a large-scale mutant library, and the microspore EMS mutagenesis is conducive to rapidly obtaining homozygous mutants. [ABSTRACT FROM AUTHOR]

There is a dearth of information on the effect of macadamia husk compost (MHC) on the productivity of short-season, shallow-rooted annual crops. We assessed the response of yield and nutrient uptake of Chinese cabbage (Brassica rapa L. Chinensis) to MHC application. The treatments (zero control, inorganic fertilizer (100:60:60 kg NPK ha−1), and 15 and 30 t ha−1 MHC) were arranged in a randomized complete block design and replicated three times. Number of leaves, leaf area index, leaf biomass, and leaf nutrient concentration (N, P, K, Ca, Mg, Zn, Cu, Mn, and B) were determined at 28, 46, and 74 days after transplanting (DAT), and root length and root biomass were determined at 74 DAT. Inorganic fertilizer and MHC increased root biomass and root length with greater increases recorded at the higher MHC rates. Number of leaves, leaf area index, leaf biomass, and nutrient concentration were greater with application of inorganic fertilizer (28 DAT) and 30 t ha−1 (74 DAT) suggesting that the effect of organic soil amendments is more pronounced over the long run compared with inorganic fertilizers. The concentration of macronutrients in the leaf increased with application of MHC and inorganic fertilizer. Clearly, MHC may be beneficial in improving the leaf yield and nutrient uptake of Chinese cabbage in a loamy sand soil, but the effect varies with time of harvesting. [ABSTRACT FROM AUTHOR]

Nitrate transporters (NRTs) play an important role in nitrate absorption and internal distribution in plant roots and other parts. Experiments were carried out to explore the sequences and expression characteristics of NRT genes, and their correlation with the N uptake in flowering Chinese cabbage. We have isolated three important BcNRTs (BcNRT1.1, BcNRT1.2, and BcNRT2.1) from flowering Chinese cabbage. Spatio-temporal expression analysis found that BcNRT1.1 and BcNRT2.1 were mainly expressed in roots, while BcNRT1.2 was more expressed in roots than in leaves during vegetative growth and was mainly expressed in leaves during reproductive growth. The NO3− uptake rate of the entire growth period was significantly correlated with BcNRT1.1 and BcNRT1.2 expression in roots. In addition, the total N content was increased with the increase in NO3− concentration in flowering Chinese cabbage. The NH4+ uptake was slightly induced by NH4+, but the total N content had no significant difference under the NH4+ concentration of 1–8 mmol/L. We also found that lower concentrations of NH4+ promoted the expression of BcNRT1.1 and BcNRT1.2 while inhibiting the expression of BcNRT2.1 in the roots of flowering Chinese cabbage. The amount of total N uptake in the treatment with 25/75 of NH4+/NO3− was significantly higher than that of the other two treatments (0/100 and 50/50). In the mixture of NH4+ and NO3−, total N uptake was significantly correlated with the BcNRT1.2 expression. We concluded that mixed nutrition with an NH4+/NO3− of 25/75 could significantly increase total nitrogen uptake in flowering Chinese cabbage, in which two members of the NRT1 subfamily (BcNRT1.1 and BcNRT1.2) might play a major regulatory role in it. This study is a beneficial attempt to dig deeper into the NRT genes resources and lays the foundation for the ultimate use of genetic improvement methods to increase the NUE with less nitrogen fertilizer in flowering Chinese cabbage. [ABSTRACT FROM AUTHOR]

Use of season extension tools such as high tunnels and diverse vegetable crops have been crucial in improving competitiveness of vegetable growers in Mississippi who operate on small- to medium-sized farms. Chinese cabbage, also known as pak choy or bok choy, has become increasingly popular due to numerous cultivar choices, fast maturity, high productivity, tolerance for frost, and its potential use for winter production in high tunnels in a subtropical climate. Five Chinese cabbage cultivars including ‘Asian Delight’, ‘Black Summer’, ‘Red Pac’, ‘Rosie’, and ‘Tokyo Bekana’ were evaluated for plant growth, yield, and mineral nutrient concentrations when grown with three types of biodegradable plastic mulches (BDMs) and one polyethylene (PE, or plastic) mulch in a high tunnel in two experiments from 30 October 2019 to 18 March 2020. The five tested cultivars varied in plant height, widths, leaf SPAD, fresh and dry plant weights, marketable yield, and macro- and micro-nutrient concentrations. ‘Tokyo Bekana’ produced the highest marketable yield and fresh and dry plant weights in both experiments. The three BDMs resulted in similar marketable yield and mineral nutrients in tested cultivars and similar temperatures of leaf, mulch, and substrate compared to the PE mulch. The high tunnel provides a viable way for the winter production of selected Chinese cabbage cultivars in a subtropical climate with possible different yields between production cycles due to varying microenvironment in those months. [ABSTRACT FROM AUTHOR]

Purple heading Chinese cabbage has become popular in recent years due to its attractive color and health benefits. However, purple varieties remain rare, and the regulation mechanism of anthocyanin accumulation in Chinese cabbage is still largely unknown. By introducing the purple color trait from Brassica juncea, a new purple heading Chinese cabbage cultivar (18M-245) was generated with deep purple leaves at both the seedling and adult stages. Anthocyanin accumulation in 18M-245 increased when grown at low temperatures. FISH and genotyping results showed that the purple trait was caused by an alien chromosome addition line derived from the Brassica B genome. The LDOX coding gene BjuB014115 from the addition line was highly expressed in 18M-245, consistent with the results of anthocyanin accumulation. Meanwhile, several MYB and bHLH transcriptional factors from the Brassica A genome were found to directly bind to the promoter of BjuB014115, suggesting that interactions between the Brassica A and B genomes are involved in the regulatory network of anthocyanin biosynthesis in Chinese cabbage. Our results provide new insights into the regulation mechanism of anthocyanin biosynthesis in purple heading Chinese cabbage.

As an important genetic improvement technique in current production practice, heterosis is widely used to enhance the productive traits of hybrid progeny from their parents. Alternative splicing (AS) analysis can be used as a method for exploring the molecular manifestations of heterosis. In our research, 16 hybrids and their parents were utilized to analyze the heterosis performance and AS events. Statistics of plant gross weight (PGW) showed that these hybrids had prominent heterosis, with the mid-parent heterosis values (MPV) ranging from 15.69% to 233.98%. Through pairwise comparison among the female parent, male parent, and hybrid, there were 2980–3205 AS events in each combination, with intron retention being the most common type followed by alternate 3’ splice site, alternative 5’ splice site, skipped exon, and mutually exclusive exon.There were 263–409 differential AS genes (DASGs) between the female parent and the hybrid, and 234–425 DASGs between the male parent and the hybrid in cross combinations. The DASGs were significantly enriched in 33 metabolic pathways in 16 cross combinations, and DASGs of different cross combinations were enriched in different metabolic pathways. Moreover, 76 DASGs in the strong heterosis combinations were identified and significantly enriched in the metabolic pathways related to amino acid metabolism. Further analysis revealed that most of these DASGs in amino acid metabolism were expressed differently in strong heterosis combinations. In addition, the expression levels of BraA06g014310.3C and BraA03g041700.3C in amino acid metabolism significantly correlated with PGW. These results could provide an index for future studies of the genetic and molecular mechanism of heterosis in hybrids.

Leafy head formation is one of the most important characteristics of Chinese cabbage, and the process is regulated by a series of genes and environmental factors. In this study, a non-heading short leaf mutant slm was identified from an ethyl methane sulfonate mutagenesis (EMS) population of the heading Chinese cabbage line FT. The most significant phenotypic characteristics of slm was shortening leaves and increasing leaf numbers, which led to failure to form a leafy head. Genetic analysis showed that a single recessive gene Brslm was responsible for the mutant phenotype. Mutmap analysis suggested that Brslm was located on chromosome A07, and four candidate genes were predicted. KASP analysis demonstrated that BraA07g039390.3C was the target gene of the candidates. BraA07g039390.3C is a homologous to Arabidopsis CLV1 encoding receptor kinase with an extracellular leucine-rich domain. Sequencing analysis revealed that a single SNP from G to A occurred in 904th nucleotide of Brclv1, which resulted in the change of the 302nd amino acid from Asp to Asn. The SNP was co-segregated with the mutant phenotype in F2 individuals and located on the conserved domains. These results indicated that BrCLV1 was the mutant gene for slm which led to shortening leaves and increasing leaf numbers, disrupting the leafy heading formation in FT. These findings contribute to revealing the BrCLV1 function in leafy head formation in Chinese cabbage.

With increasing nitrogen application in soil, the problem of nitrate accumulation in soil and vegetable bodies has become increasingly serious. In this study, Bacillus subtilis (B. subtilis) Strain11 was isolated and studied for its effects in combination with Molybdenum (Mo) on the growth of Chinese cabbage and soil nitrate content. The results showed that the strain effectively increased the growth, height, and moisture content of Chinese cabbage by 27% and 2.5%, respectively, compared to the control. Mo application alone reduced soil nitrate accumulation and increased root length, height, chlorophyll content, and moisture content of Chinese cabbage, with an optimal rate of 0.8–1.2 mg/kg soil. The application of Mo fertilizer in combination with the Bacillus strain was the most effective in increasing plant height and root length of Chinese cabbage, which were 1.49 times and 1.68 times that of the control, respectively. The proportion of dry matter, the average fresh weight, and the dry weight under this treatment were 9.01%, 5.83 g/plant, and 0.53 g/plant, respectively, higher than the rest. At harvest, the highest ammonium-nitrogen content in this treatment group was 8.56 mg/kg, and the soil nitrate reduction reached 40.68%. In conclusion, Mo fertilizer at a rate of 0.8 mg Mo/kg soil, in combination with B. subtilis Strain11, was recommended for the remediation of nitrate-contaminated soils.

Ogura cytoplasmicmale sterility (Ogura CMS), originally identified in wild radish (Raphanus sativus), has enabled complete pollen sterility in Brassica plants, but the underlying mechanism in Ogura CMS Chinese cabbage (Brassica rapa ssp. pekinensis) remains unclear. In this study cytological analysis showed that during microsporogenesis the meiosis occurred normally, and the uninucleated pollens subsequently formed, but the development of both binucleated and trinucleated pollens was obviously disrupted due to defects of pollen mitosis in the Ogura CMS line (Tyms) compared with the corresponding maintainer line (231–330). In transcriptome profiling a total of 8052 differentially expressed genes (DEGs) were identified, among which 3890 were up-regulated and 4162 were downregulated at the pollen abortion stages in an Ogura CMS line. KOG cluster analysis demonstrated that a large number of DEGs were related to the cytoskeleton’s dynamics, which may account for the failure of pollen mitosis during development in the Ogura CMS line. The pivotal genes related to the phenylpropane synthesis pathway (PAL, 4CL and CAD) were significantly down-regulated, which probably affected the formation and disposition of anther lignin and sporopollenin, and eventually led to abnormality in the pollen exine structure. In addition, several key up-regulated genes (GPX7, G6PD and PGD1) related to the glutathione oxidation-reduction (REDOX) reaction indicated that the accumulation of peroxides in Ogura CMS lines during this period affected the pollen development. Taken together, this cytological and molecular evidence is expected to advance our understanding of pollen abortion induced by Ogura cytoplasmic action in Chinese cabbage. [ABSTRACT FROM AUTHOR]

Mutagenesis is an important tool for breeding and genomic research. In this study, the germinated seeds and isolated microspores of a double haploid line ‘FT’ were treated with EMS, respectively, with the aim of comparing the effects of the two approaches on generating mutants in Chinese cabbage. For microspore EMS mutagenesis, the isolated microspores were treated with 0.12% EMS for 20 min, a total of 1268 plantlets were obtained, and 15 M1 mutants were screened with a mutation frequency of 1.2%. For seed EMS mutagenesis, 7800 germinated seeds were treated with 0.8% EMS for 12 h, and a total of 701 M2 mutants were screened, with a mutation frequency of 18.78%. In total, 716 mutants with heritable morphological variation including leaf color, leaf shape, leafy head, bolting, and fertility, were obtained from the EMS mutagenesis experiments. Homozygous mutant plants could be screened from M1 lines by microspore mutagenesis, and M2 lines by seed mutagenesis. The mutation frequency was higher in seed mutagenesis than in microspore mutagenesis. Based on these results, we propose that seed EMS mutagenesis is more suitable to generate a large-scale mutant library, and the microspore EMS mutagenesis is conducive to rapidly obtaining homozygous mutants.

Chinese cabbage (Brassica rapa L. ssp. pekinensis) is one of the most widely cultivated and economically important vegetables in China. Constructing an effective genetic linkage map and mapping quantitative trait loci (QTLs) related to yield and leafy head morphology is of great importance for molecular breeding of Chinese cabbage. Using two diverse Chinese cabbage inbred lines, ZHB and G291, as parents, an F2 segregating population consisting of 240 individuals was prepared for genetic map construction and phenotype investigation in this study. The two parents are significantly different in both shape and size. Sixteen important agronomic traits of F2 individuals were investigated. A genetic map of 105 intragenic simple sequence repeat (SSR) markers distributed across 10 linkage groups (LGs) was constructed, which was 2034.1 cM in length and had an average inter-locus distance of 21.75 cM. We identified 48 QTLs for the tested important agronomic traits on the studied LGs, with LOD scores of 2.51–12.49, which explained the phenotypic variance of 3.41–26.66%. The QTLs identified in this study will facilitate further genetic analysis and marker-assisted genetic improvement of Chinese cabbage.

Chinese cabbage (Brassica rapa L. ssp. pekinensis) is one of the most widely cultivated and economically important vegetables in China. Constructing an effective genetic linkage map and mapping quantitative trait loci (QTLs) related to yield and leafy head morphology is of great importance for molecular breeding of Chinese cabbage. Using two diverse Chinese cabbage inbred lines, ZHB and G291, as parents, an F2 segregating population consisting of 240 individuals was prepared for genetic map construction and phenotype investigation in this study. The two parents are significantly different in both shape and size. Sixteen important agronomic traits of F2 individuals were investigated. A genetic map of 105 intragenic simple sequence repeat (SSR) markers distributed across 10 linkage groups (LGs) was constructed, which was 2034.1 cM in length and had an average inter-locus distance of 21.75 cM. We identified 48 QTLs for the tested important agronomic traits on the studied LGs, with LOD scores of 2.51–12.49, which explained the phenotypic variance of 3.41–26.66%. The QTLs identified in this study will facilitate further genetic analysis and marker-assisted genetic improvement of Chinese cabbage. [ABSTRACT FROM AUTHOR]

Molecular marker-assisted gene pyramiding combined with backcrossing has been widely applied for crop variety improvement. Molecular marker identification could be used in the early stage of breeding to achieve the rapid and effective pyramiding of multiple genes. To create high-quality germplasm for Chinese cabbage breeding, multi-gene pyramiding for self-compatibility, multilocular, and clubroot resistance was performed through molecular marker-assisted selection. The results showed that self-compatibility and multilocular traits were controlled by a pair of recessive genes. Two flanking markers, sau_um190 and cun_246a, and marker Teo-1, based on the gene sequence related to multilocular ovaries, were used for multilocular ovary trait selection. Two flanking markers, SCF-6 and SC-12, and marker Sal-SLGI /PK1+PK4, based on the gene sequence, were used for self-compatibility selection. Two flanking markers, TCR74 and TCR79, closely linked to clubroot resistance gene CRb, were used as foreground selection markers. Based on Chinese cabbage genomic information, 111 SSR markers covering 10 chromosomes were applied for background selection. After multiple generations of selection, a multi-gene pyramided line from a BC4F2 population with self-compatibility, multilocular ovaries, and clubroot resistance was obtained with a high genomic background recovery rate. The improved pyramided line is expected to be utilized as a potential material in further breeding programs. [ABSTRACT FROM AUTHOR]