Brassica Rapa Research Articles

Novel sources of resistance to bacterial leaf blight in the USDA Brassica rapa collection

Bacterial leaf blight (BLB), caused by Pseudomonas cannabina pv. alisalensis (Pcal), is a devastating disease that has spread worldwide over the past twenty years. Pcal can infect all Brassica crops and leads to yield losses of Brassica leafy greens across the Southeastern US every year. There are no commercial cultivars of turnip greens with resistance to Pcal and no effective bactericides available. We report the first identification of resistant sources in Brassica rapa L. against bacterial leaf blight, caused by Pcal. The USDA accessions of B. rapa (275 accessions) were screened through multiple tests in greenhouse trials. The three commercial cultivars tested exhibited an intermediate response across all tests and re-tests. Three accessions (Ames 7572, PI 649171, and PI 649183) with significant resistance were identified in the B. rapa germplasm collection. The identified accessions are an important source for development of B. rapa cultivars resistant to Pcal and introgression of the resistant loci into B. napus cultivars.

Comprehensive genome-wide identification of Snf2 gene family and their expression profile under salt stress in six Brassica species of U's triangle model.

We comprehensively identified and analyzed the Snf2 gene family. Some Snf2 genes were involved in responding to salt stress based on the RNA-seq and qRT-PCR analysis. Sucrose nonfermenting 2 (Snf2) proteins are core components of chromatin remodeling complexes that not only alter DNA accessibility using the energy of ATP hydrolysis, but also play a critical regulatory role in growth, development, and stress response in eukaryotes. However, the comparative study of Snf2 gene family in the six Brassica species in U's triangle model remains unclear. Here, a total of 405 Snf2 genes were identified, comprising 53, 50, and 46 in the diploid progenitors: Brassica rapa (AA, 2n = 20), Brassica nigra (BB, 2n = 16), and Brassica oleracea (CC, 2n = 18), and 93, 91, and 72 in the allotetraploid: Brassica juncea (AABB, 2n = 36), Brassica napus (AACC, 2n = 38), and Brassica carinata (BBCC, 2n = 34), respectively. These genes were classified into six clades and further divided into 18 subfamilies based on their conserved motifs and domains. Intriguingly, these genes showed highly conserved chromosomal distributions and gene structures, indicating that few dynamic changes occurred during the polyploidization. The duplication modes of the six Brassica species were diverse, and the expansion of most Snf2 in Brassica occurred primarily through dispersed duplication (DSD) events. Additionally, the majority of Snf2 genes were under purifying selection during polyploidization, and some Snf2 genes were associated with various abiotic stresses. Both RNA-seq and qRT-PCR analysis showed that the expression of BnaSnf2 genes was significantly induced under salt stress, implying their involvement in salt tolerance response in Brassica species. The results provide a comprehensive understanding of the Snf2 genes in U's triangle model species, which will facilitate further functional analysis of the Snf2 genes in Brassica plants.

Utilizing recycled pumice and oyster shell waste for cost-effective treatment to mitigate pollutants and toxicity in swine wastewater

Despite the abundant nutrients that could be reutilized in swine wastewater, inadequate wastewater management leads to excessive metals and organic matter, causing environmental impacts on aquatic and terrestrial ecosystems. In this study, we recycled waste pumice and oyster shells for the cost-effective treatment and reclamation of swine wastewater. The toxicity of the treated wastewater was assessed using the soil nematode Caenorhabditis elegans and Chinese cabbage Brassica rapa chinensis. Our findings showed significant removal of suspended solids, biochemical oxygen demand, chemical oxygen demand, total phosphorus, and heavy metals (As, Cu, Ni, and Zn) from the swine wastewater after treatment with pumice and oyster shells. Moreover, untreated wastewater significantly inhibited the germination of Chinese cabbage, a trend that was reversed in treated wastewater. Both treated and untreated swine wastewater stimulated the growth of Chinese cabbage. Additionally, untreated swine wastewater exhibited high toxicity to the growth and reproduction of C. elegans after 72 hours of exposure, whereas treated wastewater showed notably reduced toxicity. The recycled pumice and oyster shells significantly induced growth and showed no toxicity in Chinese cabbage. These results suggest that pumice and oyster shell waste can effectively reduce environmental toxicity in raw swine wastewater, offering a cost-effective wastewater treatment solution for small-scale pig farms.

Defense of cabbages against herbivore cutworm Spodoptera litura under Cd stress and insect herbivory stress simultaneously

Biotic (e.g., heavy metal) and abiotic stress (e.g., insect attack) can affect plant chemical defense, but little is known about the changes in plant defense when they occur concurrently. Herein, the impacts of heavy metal cadmium (Cd) stress and insect herbivory stress on the direct and indirect defense of two cultivar cabbages of Brassica campestris, the low-Cd cultivar Lvbao701 and the high-Cd cultivar Chicaixin No.4, against the herbivore cutworm Spodoptera litura were investigated. Although 10 mg kg−1 Cd stress alone inhibited leaf secondary metabolites (total phenolics, flavonoids), it reduced the feeding rate and odor selection of S. litura towards both cultivar cabbages, especially for Lvbao701, by increasing leaf Cd content and repellent volatile organic compounds (VOCs) (6-methyl-5-hepten-2-one, 7,9-di-tert-butyl-1-oxaspiro (4,5)deca-6,9-diene-2,8-dione), and reducing soluble sugar and attractive VOCs (3-methyl-3-pentanol, 2,5-hexanedione, tetradecanal). Under 2.5 mg kg−1 Cd and herbivory stress, although leaf total phenolics and flavonoids increased significantly, the feeding rate and odor selection of S. litura towards both cultivar cabbages increased, especially for Chicaixin No.4, indicating that the chemical defense of cabbages was depressed. Therefore, Cd stress alone improved the insect resistance of cabbages, whereas herbivory stress weakened the enhanced cabbages defence by Cd stress. The low-Cd cultivar Lvbao701 presented stronger insect resistance than Chicaixin No.4, suggesting that Lvbao701 application in Cd-polluted soil can not only decrease Cd transmission to higher levels in the food chain but also reduce pest occurrence.

Characterization of Probiotic Potential Lactic Acid Bacteria Isolated from Chinese Cabbage Brassica rapa subsp. Pekinensis

ABSTRACT This study aimed to isolate and evaluate the probiotic potential of lactic acid bacteria (LAB) from Chinese cabbage (Brassica rapa subsp. pekinensis) that is typically used in Kimchi, a Korean fermented product. Lactococcus lactis VLC.1 and VLC.2, and Lactococcus garvieae VLC.3 were identified and further assessed for their probiotic properties. These strains exhibited biological activity such as antioxidant capabilities, antimicrobial activity against pathogenic bacteria, hydrophobicity, and co-aggregation. These findings suggest their potential as probiotics to alleviate oxidative stress and maintain gastrointestinal flora balance. Significantly, the cell-free supernatants derived from LAB isolates exhibited synergistic antimicrobial activity with effectiveness against Escherichia coli, providing novel strategies to address antibiotic resistance challenges. The LAB isolates showed no antibiotic resistance and lacked hemolytic activity, underscoring their safety and efficacy as probiotics. In summary, our findings contribute valuable insights into the biological and safety properties of LAB strains isolated from Chinese cabbage, highlighting their functional benefits.

BcWRKY1 confers Botrytis cinerea susceptibility via inhibiting JA biosynthesis.

WRKYs play important roles in plant stress resistance. However, the role of WRKYs in non-heading Chinese cabbage (Brassica campestris ssp. chinensis) against Botrytis cinerea (B. cinerea) remains poorly understood. Herein, the expression of BcWRKY1 was induced by B. cinerea. Further, the role of BcWRKY1 in B. cinerea infection was identified. Silencing of BcWRKY1 in non-heading Chinese cabbage enhanced plant resistance to B. cinerea. After B. cinerea inoculation, BcWRKY1-silencing plants exhibited lower reactive oxygen species (ROS) content, higher jasmonic acid (JA) content, and the expression level of JA biosynthesis genes, BcOPR3, BcLOX3-1 and BcLOX3-2 were upregulated. Overexpression of BcWRKY1 in Arabidopsis exhibited a complementary phenotype. By directly targeting W-boxes in the promoter of BcLOX3-2, BcWRKY1 inhibited the transcription of this gene. In addition, 13 candidate interacting proteins of BcWRKY1 were identified by yeast two-hybrid (Y2H) screening, and the interaction between BcWRKY1 and BcCaM6 weakened the inhibition of BcLOX3-2. In summary, our findings suggest that BcWRKY1 interacts with BcCaM6 to negatively regulate disease resistance.

Methyl jasmonate-induced bHLH42 mediates tissue-specific accumulation of anthocyanins via regulating flavonoid metabolism-related pathways in Caitai.

Anthocyanin is a type of plant secondary metabolite beneficial to human health. The anthocyanin content of vegetable and fruit crops signifies their nutritional quality. However, the molecular mechanism of anthocyanin accumulation, especially tissue-specific accumulation, in Caitai, as well as in other Brassica rapa varieties, remains elusive. In the present study, taking advantage of three kinds of Caitai cultivars with diverse colour traits between leaves and stems, we conducted a comparative transcriptome analysis and identified the molecular pathway of anthocyanin biosynthesis in Caitai leaves and stems, respectively. Our further investigations demonstrate that bHLH42, which is robustly induced by MeJA, closely correlates with tissue-specific accumulation of anthocyanins in Caitai; bHLH42 upregulates the expression of flavonoid/anthocyanin biosynthetic pathway genes to activate anthocyanin biosynthesis pathway, importantly, overexpression of bHLH42 significantly improves the anthocyanin content of Caitai. Our analysis convincingly suggests that bHLH42 induced by jasmonic acid signalling plays a crucial role in tissue-specific accumulation of anthocyanins in Caitai.

The Formulation and Characterization of Antimicrobial Packaging from Chitosan and Curry Leaf (Murraya Koenigii) Essential Oil for Vegetables Packaging

This study formulated chitosan-based antimicrobial films incorporating curry leaf (Murraya koenigii) essential oil using the film casting method. The films were characterized with 0%, 1%, and 2% concentrations of essential oil, and evaluated through physical, mechanical, and biological tests. Physical and mechanical tests included tensile testing, film thickness, pH, and water solubility. The film thickness ranged from 0.04 mm to 0.08 mm, and pH values ranged from 3.84 to 4.93. Water solubility was 22.7%, 20.56%, and 40.17% for films with 0%, 1%, and 2% essential oil, respectively. Tensile strength was assessed alongside antimicrobial properties using the zone of inhibition method against E. coli and Bacillus cereus. The films showed significant inhibition zones for the gram-negative E. coli and minimal inhibition for the gram-positive B. cereus. Shelf-life tests on dwarf pak choi (Brassica rapa chinensis) and baby kailan (Brassica oleracea L.) demonstrated an extended shelf-life of up to 14 days using common storage methods such as on-top placement and wrapping. This study concludes that chitosan-based films infused with curry leaf essential oil exhibit promising antimicrobial properties, making them a viable food packaging material with considerable strength, elongation, and flexibility, effectively inhibiting foodborne pathogens.

Temperature-dependent jumonji demethylase modulates flowering time by targeting H3K36me2/3 in Brassica rapa

Global warming has a severe impact on the flowering time and yield of crops. Histone modifications have been well-documented for their roles in enabling plant plasticity in ambient temperature. However, the factor modulating histone modifications and their involvement in habitat adaptation have remained elusive. In this study, through genome-wide pattern analysis and quantitative-trait-locus (QTL) mapping, we reveal that BrJMJ18 is a candidate gene for a QTL regulating thermotolerance in thermotolerant B. rapa subsp. chinensis var. parachinensis (or Caixin, abbreviated to Par). BrJMJ18 encodes an H3K36me2/3 Jumonji demethylase that remodels H3K36 methylation across the genome. We demonstrate that the BrJMJ18 allele from Par (BrJMJ18Par) influences flowering time and plant growth in a temperature-dependent manner via characterizing overexpression and CRISPR/Cas9 mutant plants. We further show that overexpression of BrJMJ18Par can modulate the expression of BrFLC3, one of the five BrFLC orthologs. Furthermore, ChIP-seq and transcriptome data reveal that BrJMJ18Par can regulate chlorophyll biosynthesis under high temperatures. We also demonstrate that three amino acid mutations may account for function differences in BrJMJ18 between subspecies. Based on these findings, we propose a working model in which an H3K36me2/3 demethylase, while not affecting agronomic traits under normal conditions, can enhance resilience under heat stress in Brassica rapa.

Karakterisasi dan Potensi Acremonium sp. Secara In Vitro Terhadap Cendawan Patogen Fusarium oxysporum

Various natural interactions exist between fungi and plants, including mutualism and pathogenesis. This study evaluated the interaction of fungi Acremonium sp. to plants and pathogenic fungi. Acremonium sp. was isolated from the root tissue of an oil palm plant using surface sterilization methods before isolation. The potential pathogenicity interaction of Acremonium sp. was assayed towards Chinese white cabbage (Brassica rapa L. var. pekinensis) in vitro. Based on the PDA medium assay, isolated Acremonium sp. exhibited pathogenic traits against Chinese white cabbage within 14 days post-inoculation. Interestingly, Acremonium sp. showed antifungal activity against Fusarium oxysporum IPBCC.19.1468, with an average inhibition rate of 69.11%. Our data suggest the pathogenicity interaction of Acremonium sp. toward cabbage plant and fungi F. oxysporum IPBCC.19.1468.

Genome-Wide Identification and Expression Analysis of BrBASS Genes in Brassica rapa Reveals Their Potential Roles in Abiotic Stress Tolerance.

The bile acid sodium symporter (BASS) family plays an important role in transporting substances and coordinating plants' salt tolerance. However, the function of BASS in Brassica rapa has not yet been elucidated. In this study, eight BrBASS genes distributed on five chromosomes were identified that belonged to four subfamilies. Expression profile analysis showed that BrBASS7 was highly expressed in roots, whereas BrBASS4 was highly expressed in flowers. The promoter element analysis also identified several typical homeopathic elements involved in abiotic stress tolerance and stress-related hormonal responses. Notably, under salt stress, the expression of BrBASS2 was significantly upregulated; under osmotic stress, that of BrBASS4 increased and then decreased; and under cold stress, that of BrBASS7 generally declined. The protein-protein interaction analysis revealed that the BrBASS2 homologous gene AtBASS2 interacted with Nhd1 (N-mediated heading date-1) to alleviate salt stress in plants, while the BrBASS4 homologous gene AtBASS3 interacted with BLOS1 (biogenesis of lysosome-related organelles complex 1 subunit 1) via co-regulation with SNX1 (sorting nexin 1) to mitigate an unfavorable growing environment for roots. Further, Bra-miR396 (Bra-microRNA396) targeting BrBASS4 and BrBASS7 played a role in the plant response to osmotic and cold stress conditions, respectively. This research demonstrates that BrBASS2, BrBASS4, and BrBASS7 harbor great potential for regulating abiotic stresses. The findings will help advance the study of the functions of the BrBASS gene family.

Influence of different pre-cooling methods on the freshness preservation of bok choi(Brassica rapa var. chinensis)

Several pre-cooling methods for bok choi were used, such as natural convection pre-cooling (NCPC), strong wind pre-cooling (SWPC), vacuum pre-cooling (VPC), cold water pre-cooling (CWPC), electrolyzed water pre-cooling (EWPC), and fluid ice pre-cooling (FIPC), in order to determine the most suitable precooling method. It was found that VPC reduced the respiration rate, inhibited the increase of malondialdehyde (MDA) and relative electrolyte leakage, and significantly decreased the total bacterial count. This may be due to the rapid decompression process during vacuum pre-cooling, which disrupts the microbial structure and has a certain sterilizing effect. Bok choi pre-cooled by VPC had the best color, hardness value, chlorophyll, titratable acid (TA) content, vitamin C (VC) content, total phenolic (TP) content, soluble sugar content, superoxide dismutase (SOD) activity, ascorbate peroxidase (APX) activity, and catalase (CAT) activity. Therefore, the most suitable pre-cooling method for bok choi among the above pre-cooling methods was the VPC method.

A comprehensive review on the chemical constituents and pharmacological activities of Mustard plants

Medicinal plants are used worldwide to combat and treat various deadly diseases. Among them, mustard plants (Brassica campestris and B. nigra) are two very common plants of medicinal value in the Asia region. These plans are used to treat neuralgia, spasms, snakebite, alopecia, epilepsy, toothache, etc. They also have some history of spiritual usage. According to various scientific studies B. campestris and B. nigra possess anticancer, antioxidant, and antibacterial activity, antiepileptic effect, antidiabetic effect, neuroprotective effect, antifungal and, anti-obesity activities, etc. Glucosinolates, polyphenols, condensed tannins, vitamins, palmitic, oleic and linolenic acids, etc. were isolated from these plants. This study makes a comprehensive review of different aspects of these plants including their description, uses, chemical constituents, pharmacological activities, with a special focus on their anti-cancer activity, adverse effects and contraindications. The chemical constituents responsible for their anticancer activity have also been highlighted. The review also covered anti-nutritional property of the plants. Jahangirnagar University J. Biol. Sci. 12(1 & 2): 107-125, 2023 (June & December)

Methyl-Sensitive Amplification Polymorphism (MSAP) Analysis Provides Insights into the DNA Methylation Changes Underlying Adaptation to Low Temperature of Brassica rapa L.

DNA methylation can change rapidly to regulate the expression of stress-responsive genes. Previous studies have shown that there are significant differences in the cold resistance of winter rapeseed (Brassica rapa L.) after being domesticated in different selection environments; however, little is known about the epigenetic regulatory mechanisms of its cold resistance formation. Four winter rapeseed materials ('CT-2360', 'MXW-1', '2018-FJT', and 'DT-7') domesticated in different environments were selected to analyze the DNA methylation level and pattern changes under low temperature using methylation-sensitive amplified polymorphism technology with 60 primer pairs. A total of 18 pairs of primers with good polymorphism were screened, and 1426 clear bands were amplified, with 594 methylation sites, accounting for 41.65% of the total amplified bands. The total methylation ratios of the four materials were reduced after low-temperature treatment, in which the DNA methylation level of 'CT-2360' was higher than that of the other three materials; the analysis of methylation patterns revealed that the degree of demethylation was higher than that of methylation in 'MXW-1', '2018-FJT', and 'DT-7', which were 22.99%, 19.77%, and 24.35%, respectively, and that the methylation events in 'CT-2360' were predominantly dominant at 22.95%. Fifty-three polymorphic methylated DNA fragments were randomly selected and further analyzed, and twenty-nine of the cloned fragments were homologous to genes with known functions. The candidate genes VQ22 and LOC103871127 verified the existence of different expressive patterns before and after low-temperature treatment. Our work implies the critical role of DNA methylation in the formation of cold resistance in winter rapeseed. These results provide a comprehensive insight into the adaptation epigenetic regulatory mechanism of Brassica rapa L. to low temperature, and the identified differentially methylated genes can also be used as important genetic resources for the multilateral breeding of winter-resistant varieties.

Too hot to handle: temperature-induced plasticity influences pollinator behaviour and plant fitness.

Increased temperature can induce plastic changes in many plant traits. However, little is known about how these changes affect plant interactions with insect pollinators and herbivores, and what the consequences for plant fitness and selection are. We grew fast-cycling Brassica rapa plants at two temperatures (ambient and increased temperature) and phenotyped them (floral traits, scent, colour and glucosinolates). We then exposed plants to both pollinators (Bombus terrestris) and pollinating herbivores (Pieris rapae). We measured flower visitation, oviposition of P. rapae, herbivore development and seed output. Plants in the hot environment produced more but smaller flowers, with lower UV reflectance and emitted a different volatile blend with overall lower volatile emission. Moreover, these plants received fewer first-choice visits by bumblebees and butterflies, and fewer flower visits by butterflies. Seed production was lower in hot environment plants, both because of a reduction in flower fertility due to temperature and because of the reduced visitation of pollinators. The selection on plant traits changed in strength and direction between temperatures. Our study highlights an important mechanism by which global warming can change plant-pollinator interactions and negatively impact plant fitness, as well as potentially alter plant evolution through changes in phenotypic selection.

Editing of eIF(iso)4E.c confers resistance against Turnip mosaic virus in Brassica rapa

Turnip mosaic virus (TuMV) constitutes one of the primary diseases affecting Brassica rapa, severely impacting its production and resulting in crop failures in various regions worldwide. Recent research has demonstrated the significance of plant translation initiation factors, specifically the eIF4E and eIF4G family genes, as essential recessive disease resistance genes. In our study, we conducted evolutionary and gene expression studies, leading us to identify eIF(iso)4E.c as a potential TuMV-resistant gene. Leveraging CRISPR/Cas9 technology, we obtained mutant B. rapa plants with edited eIF(iso)4E.c gene. We confirmed eIF(iso)4E.c confers resistance against TuMV through phenotypic observations and virus content evaluations. Furthermore, we employed ribosome profiling assays on eif(iso)4e.c mutant seedlings to unravel the translation landscape in response to TuMV. Interestingly, we observed a moderate correlation between the fold changes in gene expression at the transcriptional and translational levels (R2 = 0.729). Comparative analysis of ribosome profiling and RNA-seq data revealed that plant–pathogen interaction, and MAPK signaling pathway–plant pathways were involved in eIF(iso)4E.c-mediated TuMV resistance. Further analysis revealed that sequence features, coding sequence length, and normalized minimal free energy, influenced the translation efficiency of genes. Our study highlights that the loss of eIF(iso)4E.c can result in a highly intricate translation mechanism, acting synergistically with transcription to confer resistance against TuMV.

Microplastic and cadmium contamination: Impact on the soil by inhibiting the growth of pak choi (Brassica rapa subsp. chinensis)

Microplastics are persistent pollutants that elicit significant environmental and health concerns; however, little is known about their interactions with cadmium (Cd) and their toxic effects on soil and plant growth. A pot study was conducted to examine the effects of polyethylene (PE; 0.05 % w/w), polylactic acid (PLA; 0.05 % w/w), and Cd application (5 mg kg−1 soil) in a soil-plant system. Sole application of PE and soil contamination with Cd negatively influenced the biomass, soil properties, Cd accumulation, photosynthetic properties, chlorophyll content, root growth traits, and antioxidant enzyme activity. PE+Cd exerted stronger adverse effects on biomass, soil properties, Cd accumulation, photosynthetic properties, chlorophyll content, root growth traits, and antioxidant enzyme activity. PLA+Cd decreased Cd uptake and accumulation in leaves and roots. PE+Cd upregulated the antioxidant activities (APX, CAT, POD, and SOD contents) in the root and leaves, compared to that by PLA. Both types of microplastics, especially PE, are affected by oxidative stress caused by Cd-contaminated soil. In conclusion, PE+Cd had stronger adverse effects on soil health and pak choi physiology, thereby affecting roots and leaf biomass. Long-term experiments are required to enhance our understanding of microplastic in bioremediation.

Do flower-colonizing microbes influence floral evolution? A test with fast-cycling Brassica.

Pollinators are thought to be the main drivers of floral evolution. Flowers are also colonized by abundant communities of microbes that can affect the interaction between plants and their pollinators. Very little is known, however, about how flower-colonizing microbes influence floral evolution. Here we performed a 6-generation experimental evolution study using fast-cycling Brassica rapa, in which we factorially manipulated the presence of pollinators and flower microbes to determine how pollinators and microbes interact in driving floral evolution. We measured the evolution of 6 morphological traits, as well as the plant mating system and flower attractiveness. Only one of the 6 traits (flower number) evolved in response to pollinators, while microbes did not drive the evolution of any trait, nor did they interact with pollinators in driving the evolution of morphological traits. Moreover, we did not find evidence that pollinators or microbes affected the evolution of flower attractiveness to pollinators. However, we found an interactive effect of pollinators and microbes on the evolution of autonomous selfing, a trait that is expected to evolve in response to pollinator limitations. Overall, we found only weak evidence that microbes mediate floral evolution. However, our ability to detect an interactive effect of pollinators and microbes might have been limited by weak pollinator-mediated selection in our experimental setting. Our results contrast with previous (similar) experimental evolution studies, highlighting the susceptibility of such experiments to drift and to experimental artefacts.

In Brassica rapa meiotic recombination; chromosome axis remodeling is critical

The primary mechanism by which breeders generate biodiversity is meiotic recombination, which permits genetic rearrangement at every generation. It facilitates the accumulation of advantageous alleles and eliminates harmful mutations. With the development of one to very rarely more than three crossovers that are not randomly distributed, this mechanism is highly regulated. To ensure correct parental chromosomal segregation and the creation of unique allelic combinations, meiotic recombination is essential. Finding the variables affecting the rate and distribution of meiotic crossings (COs) is crucial because this process is strictly regulated, especially for plant breeding initiatives. Nevertheless, few high-resolution recombination maps exist for most crops, including the Brassica genus, and little is known regarding sex differences and intraspecific variation. Here, using progenies of cross populations from the crossed F1s population, we reveal fine-scale resolution recombination landscapes for two female and one male cross in Brassica rapa. Parents are from very different lines, which stands for higher quality and yield.

Enhancing Bok Choy growth through synergistic effects of hydrogel and different nitrogen fertilizer forms

The application of hydrogel to sandy soil has shown promise in enhancing crop production, offering alternative solutions to address the growing food demand. Here, we investigated the impact of hydrogel and different nitrogen (N) fertilizer forms (NH4+, NO3− and Urea) on Bok Choy (Brassica rapa var. chinensis) production through the evaluation of the plant growth parameters, photosynthesis, nutrient uptake, and soil physicochemical properties. Our findings reveal that the application of hydrogel significantly increased plant height (16.27 %), fresh weight (FW) (61.14 %), dry weight (DW) (65.69 %) weight, plant nutrient concentration, and uptake. Additionally, it improved photosynthetic parameters and induced alterations in soil physicochemical properties. The synergistic effects of hydrogel varied with different nitrogen forms, with NH4+–N fertilizer demonstrating the most efficiency in enhancing Bok Choy production (119.65 % FW) compared to control. Pearson correlation analysis established close associations between Bok Choy growth parameters, photosynthesis, nutrient accumulation, and soil physicochemical properties. Principal component analysis (PCA) underscored the significant influence of hydrogel and NH4+–N on various growth parameters in Bok Choy. The stimulated growth observed can be attributed to increased nutrient uptake, improved photosynthesis, and the maintenance of soil physicochemical properties. These findings carry significant implications for the practical application of hydrogel in the field, providing a valuable strategy to enhance nutrient use efficiency and crop production in sandy soil.