Search Results (112)

Organic vegetable cultivation requires soil management strategies that improve carbon balance and suppress soilborne diseases. This study evaluated the efficacy of acidified microbial biochar pellets (ABPM) in enhancing net ecosystem carbon balance (NECB) and suppressing clubroot disease (Plasmodiophora brassicae) during organic Chinese cabbage (Brassica rapa ssp. pekinensis) cultivation. In a field-scale evaluation, three treatments were compared: guano fertilizer (control), ABPM 27 (inoculated with Pseudomonas fluorescens 22BCO027), and ABPM 86 (inoculated with Bacillus megaterium 22BCO086). Soil incorporation of ABPM 27 and ABPM 86 significantly increased soil carbon sequestration by 29.1% and 22.4%, respectively, while simultaneously reducing cumulative greenhouse gas emissions under the experimental conditions. This resulted in positive NECB values of 2.63 and 2.94 t CO₂-eq ha⁻¹, suggesting enhanced carbon retention potential within the studied cultivation system. Beyond its impact on carbon dynamics, ABPM 27 increased marketable yield by 8.6% (77.4 t ha⁻¹) and reduced clubroot incidence by 46.2%. Rhizosphere microbial analysis revealed that ABPM 27 promoted late-season microbial diversity and the persistence of beneficial Bacillus spp. and Pseudomonas spp. populations. These findings suggest the potential multifunctional role of microbially engineered biochar pellets in improving crop production, carbon retention, and pathogen suppression under organic cultivation conditions. However, these findings are based on a single-season field experiment and NECB-based carbon balance estimates, and therefore require validation across multiple growing seasons and cultivation environments. Full article

Rapeseed is a major source of vegetable oil and contains a wide variety of metabolites. Recent advances, particularly the integration of metabolomics with other omics approaches, have enabled not only comprehensive but also detailed analyses of key metabolites that respond to specific conditions. To date, these recent advances in the metabolomics of Brassica crops have not yet been fully clarified. In this review, we seek to summarize the recent progresses in metabolomics studies of Brassica rapa, B. napus and B. juncea, introduce the key metabolites spanning nucleic acids, amino acids, fatty acids, lipids, organic acids, alkaloids, phenylpropanoids, terpenoids, flavonoids and glucosinolates uncovered by this approach, focusing on those associated with growth and development, and abiotic/biotic stresses, including macronutrient availability, temperature, water stress, salt stress, aluminum and cadmium toxicity, and infection of Sclerotinia sclerotiorum, Leptosphaeria maculans, and Plasmodiophora brassicae. Future perspectives and current challenges in metabolomics integrating with other omics are also discussed, along with its potential for breeding applications, especially in new marker discovery, trait prediction, and even metabolic selection, aimed at developing new rapeseed varieties with stable, high-yielding, and quality traits. Full article

Plant immune genes are traditionally classified as resistance genes, susceptibility genes, or positive/negative regulators of defense. However, this framework does not fully explain a subset of immune-associated genes that display paradoxical disease phenotypes, in which genetic disruption enhances resistance despite the normal involvement of these genes in defense-related processes. GSL5/PMR4 is a representative example. As a pathogen-induced callose synthase, GSL5 contributes to papillary callose deposition and structural defense. Paradoxically, loss of GSL5 confers resistance to powdery mildew through salicylic acid- and N-hydroxypipecolic acid-associated pathways, as well as broad-spectrum resistance to Plasmodiophora brassicae through jasmonic acid-dependent immunity. Here, we refer to such genes as dual-state immune regulators, whose functional presence and genetic disruption promote resistance through distinct immune states. Similar regulatory patterns have been reported in several immune-related processes, including MAPK signaling, calcium influx, membrane trafficking, and receptor-proximal immune signaling. Representative examples include the MEKK1–MKK1/MKK2–MPK4 module, CNGC2/CNGC4, EXO70B1 and BIK1. This review uses GSL5 as a central example to discuss paradoxical immune phenotypes and dual-state immune regulators in plants, focusing on their biological features, potential mechanisms, and implications for resistance breeding. Full article

Brassica napus L. is a globally important crop and its productivity is constrained by multiple abiotic stresses (salinity, drought, and heat). Calcineurin B-like proteins (CBLs) act as calcium sensors and play key roles in regulating ion homeostasis and stress-responsive signaling pathways, thereby contributing to plant adaptation under unfavorable environmental conditions. Here, through detailed bioinformatics analyses, the BnCBL gene family has been identified along with its role in tolerance to multiple abiotic stresses. The identified 17 BnCBLs comprised four groups, as in Arabidopsis thaliana. The predicted molecular weights of the CBL proteins ranged from approximately 24.35 kDa (BnCBL3 and -9) to 29.7 kDa (BnCBL5), with protein lengths spanning 213 (BnCBL3, -9, -10, -12 and -15) to 260 amino acids (BnCBL5). Sequence, promoter, and structural analyses showed that BnCBL proteins harbor palmitoylation and myristoylation motifs in their EF-hand domains, contain hormone- and stress-responsive cis-elements, and exhibit characteristic post-translational modification sites and tertiary structures. RNA-seq and RT-qPCR expression analyses showed that several BnCBL genes (BnCBL2, -6, -9, -10, and -15) exhibit differential expression (3~6-fold) under NaCl, drought, and heat stresses, as well as in response to phytohormones (IAA, GA₃, ABA, and JA). In addition, BnCBL2, -3, -6, -8, -9, -11, -12 and -16 showed significant expression (around 7-fold) against biotic stresses (Sclerotinia sclerotiorum (Lib.) de Bary and Plasmodiophora brassicae (Woronin, 1877), indicating their roles in both biotic and abiotic stress tolerance and potential utility in biotechnological breeding of stress-enduring B. napus cultivars. Full article

Salicylic acid (SA) is a key regulator of plant immunity and contributes to defence against Plasmodiophora brassicae, the causal agent of clubroot disease in canola (Brassica napus) and other crucifers. Exogenous SA applications have reduced clubroot severity in some Brassica pathosystems, yet the effectiveness of foliar SA treatment against the predominant resistance-breaking pathotype 3A in western Canada remains unclear. This study evaluated the effects of weekly foliar applications of 0, 1, 5, or 10 mM SA on clubroot development in two B. napus var. napobrassica cultivars under greenhouse and growth chamber conditions. Plants inoculated with pathotype 3A were assessed for disease severity, pathogen resting spore load, plant height, and transcript accumulation of SA-responsive genes. Overall, SA treatments resulted in modest reductions in disease severity and resting spore concentrations; however, treatment effects did not reach statistical significance in most cases. Collectively, foliar SA applications provided limited suppression of clubroot caused by pathotype 3A. Further optimization of SA concentration, timing, and delivery, particularly when targeting the root zone, may be required before SA can be considered a complementary tool in integrated clubroot management. Full article

Clubroot caused by Plasmodiophora brassicae is a devastating soil-borne disease of oilseed rape, and physiological race differentiation of the pathogen greatly hinders disease control. The differential regulatory mechanisms of different P. brassicae races on the rhizosphere microecology remain unclear. This study aimed to reveal the race-specific effects of P. brassicae on the rhizosphere microenvironment, microbial community and nitrogen cycling of oilseed rape. A pot inoculation experiment was conducted with two typical races from Sichuan Province (race 4 CZ and race 2 KD), combined with soil physicochemical determination, high-throughput sequencing and functional prediction. The results showed that CZ exhibited a higher infection rate but a lower disease index than KD. Both races significantly decreased soil pH and reshaped soil nutrient profiles. Notably, CZ treatment caused a more pronounced pH decrease and was characterized by NH₄⁺-N accumulation, whereas KD treatment was dominated by NO₃⁻-N enrichment. Bacterial alpha diversity was increased by both races, following the order KD > CZ > CK. In contrast, fungal alpha diversity was decreased by both races, showing the pattern CK > KD > CZ. Distinct rhizosphere microbial community structures were formed under different race infections, and both races reduced the abundance of nitrogen-fixing bacteria and related functional genes. These findings indicate that distinct P. brassicae races shape race-specific rhizosphere microenvironments by differentially regulating soil acidification, nutrient availability and nitrogen-cycling functional microorganisms, thereby driving divergent pathogenic outcomes. This study is the first to reveal differential regulation of the rhizosphere microecology by distinct physiological races of P. brassicae, offering new insights for region-specific management of clubroot disease. Full article

Disease resistance breeding is an important direction for the genetic improvement of Chinese cabbage. The traditional elite variety ‘Yutian Baojian’ Chinese cabbage is highly regarded for its tall cylindrical head with a pointed tip, tightly twisted wrapper leaves, and sweet taste. However, long-term cultivation has led to a significant decline in its resistance to clubroot caused by Plasmodiophora brassicae. To restore clubroot resistance while maintaining its desirable horticultural traits, this study used the clubroot-susceptible ‘Yutian Baojian’ as the recurrent parent and the resistant donor ‘Shaocai’, which carries the CRd resistance gene, to develop backcross populations. Using marker-assisted selection (MAS), plants were comprehensively screened based on foreground selection with markers tightly linked to the CRd gene, background selection with 73 genome-wide polymorphic markers, and phenotypic evaluation of horticultural traits, including plant height, plant spread, head shape, and soluble solids content. In the BC₁ population, three individuals showing high genetic similarity were selected. From the BC₂ population, four elite individuals were obtained, exhibiting 99.32% genetic similarity, stable clubroot resistance, and typical horticultural characteristics. Furthermore, three homozygous resistant inbred lines (BC₂S₂) with the ‘Yutian Baojian’ phenotype were developed. These results enrich the clubroot-resistant germplasm resources of Chinese cabbage and provide an effective MAS-based strategy for the precise improvement and germplasm innovation of local cultivars. Full article

Calcium cyanamide (CaCN₂), commercially known as Perlka^®, is re-emerging as a multifunctional nitrogen (N) fertilizer with significant agronomic and environmental advantages. Composed of 19.8% nitrogen and 50% calcium oxide (CaO), CaCN₂ not only supplies slow-release nitrogen but also acts as a liming agent, improving soil pH and structure. Its transformation pathway: cyanamide → urea → ammonium → nitrate—ensures a gradual nitrogen release that aligns with crop demand, enhances nitrogen use efficiency, and minimizes nitrate leaching and nitrous oxide emissions. Additionally, the presence of dicyandiamide, a known nitrification inhibitor, further stabilizes nitrogen in the soil. Field studies across diverse cropping systems, including curly endive and short-day onions, have demonstrated that CaCN₂ improves yield, crop quality, and soil health. In onions, preplant application of 80 kg ha⁻¹ N from CaCN₂ increased bulb yield by up to 18%, enhanced phytochemical content (e.g., phenolics and flavonoids), and reduced nitrate leaching by over 40% compared to urea and limestone ammonium nitrate (LAN). In curly endive, CaCN₂ significantly improved ascorbic acid, total soluble solids, and phenolic content, particularly in fall-grown crops, while reducing nitrate accumulation and improving physiological and recovery efficiency of applied nitrogen. Beyond its role as a nutrient supplier, CaCN₂ exhibits biocidal properties that suppress soil-borne pathogens such as Sclerotinia and Plasmodiophora brassicae, reduce weed pressure, and stimulate beneficial microbial activity. Its high calcium content also addresses physiological disorders linked to calcium deficiency, such as tip-burn and blossom-end rot. However, proper application timing and dosage are critical to avoid phytotoxicity, especially in sensitive crops. This review synthesizes current knowledge on CaCN₂’s chemical behavior, agronomic performance, and environmental implications, and identifies research gaps to guide its optimized use in climate-smart and resource-efficient agriculture. Full article

Clubroot disease caused by Plasmodiophora brassicae has greatly affected the quality and yield of Chinese cabbage. Excavating the key resistance genes and verifying their function is important for clarifying disease resistance mechanisms. Virus-induced gene silencing (VIGS) technology has been widely used in gene function research. However, the VIGS system specifically designed for the functional analysis of clubroot resistance genes is currently unavailable. In this study, it was found that the vacuum infiltration VIGS method is more effective for gene silencing than the seed soaking method. When seedlings were VIGS-treated using vacuum infiltration for 10 min, genes were effectively silenced on the 6th-35th days (d) after treatment, ensuring high seedling survival rate and plant transformation rate. To investigate the optimal inoculation time with P. brassicae, plants were inoculated 3, 6, 9, and 15 d after VIGS treatment. Results showed that the difference of clubroot resistance between gene-silenced and control plants was most significant when plants were inoculated 6 d after VIGS treatment. This result suggests that, when the target gene began to silence (6 d after VIGS), immediate inoculation with P. brassicae should be suitable for the functional study of clubroot-resistance genes. Full article

Clubroot disease, caused by Plasmodiophora brassicae, is a major global threat, causing severe yield losses of up to 100% in heavily infested fields. Interspecific hybridization is essential for the transfer of clubroot resistance genes among the Brassica species. This review aimed to describe the sources of clubroot resistance, categorize their types in Brassica crops, and identify the most effective techniques and underutilized sources for both intergeneric and interspecific hybridization. A systematic literature review served as the foundation for expert analysis, encompassing a comprehensive list of known sources of resistance and a detailed description of their characteristics, including monogenic, polygenic, dominant, and recessive traits. In addition, this review specifies techniques suitable for gene transfer, such as markers, embryo rescue, somatic hybridization, and CRISPR/Cas. Based on the literature, underutilized directions for genetic crosses have been proposed. These conclusions suggest that combining biotechnological methods, including markers, CRISPR/Cas, and embryo rescue, with intergeneric crosses offers the potential to transfer resistance genes from previously untapped sources. Full article

Clubroot, caused by Plasmodiophora brassicae, is a destructive disease of Chinese cabbage (Brassica rapa ssp. pekinensis) at all growing stages. Early detection of the disease is essential to mitigate the impact of clubroot. Here, we established an optimal algorithm for multispectral imaging combined with machine learning to detect leaf responses of highly susceptible cultivar YoulvNo.3 at different day after inoculation (DAI). Spectral data at 19 wavelengths were collected from leaf multispectral images, and key characteristic wavelengths were further extracted. Principal Component Analysis (PCA) revealed a clear separation between healthy and infected samples at 11 DAI. Four classification algorithms, including Random Forest (RF), Partial Least Squares Discriminant Analysis (PLS-DA), Support Vector Machine (SVM) and Extreme Learning Machine (ELM), were employed to construct early detection model for clubroot. SVM achieved over 81% accuracy with full-spectrum data, while ELM based on characteristic wavelengths provided the best performance, accuracy exceeding 84%. Stratified five-fold cross-validation was used to validate the optimal model. An average accuracy of 83.79% (±1.04%) and macro-averaged F1-score of 82.13% (±1.12%) across validation folds were obtained, confirming stable performance. Our findings, for the first time, identified detectable spectral differences between the healthy and infected plants at 11 DAI using leaf multispectral combined with machine learning, providing a potential application for early detection of clubroot and timely control in Chinese cabbage. Full article

Clubroot in cruciferous plants remains a significant threat to growers worldwide. We investigated whether humic acid material (HAM) could control clubroot in Chinese cabbage and broccoli as an alternative to fungicides. Six independent experiments were conducted, and the results were analyzed using a general liner mixed model (GLMM) and a network meta-analysis (NMA). Some HAM treatments significantly controlled clubroot incidence on Chinese cabbage in three experiments, but no significant effects were observed in the others. HAM treatment effects varied across experiments. The GLMM indicated that HAM treatment and the interaction between the HAM amount and planting timing were significantly associated with disease incidence. HAM effectiveness depended on application amount and planting timing after treatment. The NMA estimated a statistically significant risk ratio of 0.85 for planting four weeks after HAM treatment, suggesting low efficacy in suppressing clubroot. Two field trials aligned with the greenhouse results. Full article

Clubroot disease, caused by Plasmodiophora brassicae, is a threat to Brassica crops; therefore, understanding of host-resistance is important for developing clubroot-resistant cultivars. Using multi-omics analysis of clubroot-resistant (CR) and -susceptible (CS) near-isogenic lines (NILs) of B. napus, carrying the resistance of turnip (B. rapa var. rapifera), we characterized the host resistance mechanisms. Through proteome analysis, we identified 6626 differentially abundant proteins (DAPs) (2353 in CR-NILs, 4273 in CS-NILs) (q < 0.05), of which 50 in CR- and 62 in CS-NILs were detected across the disease developmental stages. Notable proteins included those involved in reactive oxygen species scavenging (BnaA09T0647200WE)], cell-wall modifications (BnaA04T0244300WE) and glucosinolate biosynthesis (BnaA01T0266700WE) in the CR-NILs. Additionally, disease-resistance proteins like ENHANCED DISEASE RESISTANCE 2-like (BnaA03T0055600WE) and hairpin-induced family protein YLS9 (BnaA08T0237900WE) showed increased abundance in CR-NILs. In contrast, CS-NILs exhibited decreased abundance of defense-related proteins, including proteins containing CUPIN domain (BnaA09T0578800WE) and LACCASE (BnaA02T0019200WE). Integration of proteome data with transcriptome data revealed 33 genes in CR- and 32 in CS-NILs showing a consistent pattern, including the genes related to PLANT INVERTASE/PECTIN METHYLESTERASE INHIBITOR (BnaC04T0003100WE), KELCH MOTIF (BnaC02T0374800WE), LACCASE (BnaA02T0019200WE), and antioxidant-related transcripts [GLUTATHIONE S-TRANSFERASES (BnaA03T0280900WE) and 4-HYDROXYPHENYLPYRUVATE DIOXYGENASE (BnaA09T0641500WE)]. Our findings offer valuable new targets for breeding clubroot-resistant B. napus. Full article

Clubroot, caused by the obligate parasite Plasmodiophora brassicae, is a soilborne disease affecting canola (Brassica napus) and other crucifers. Although planting resistant cultivars remains the primary strategy for managing clubroot, the emergence of resistance-breaking P. brassicae pathotypes continues to threaten canola production. In this context, soil and root microorganisms may play a role in suppressing the disease. This study investigated the impact of P. brassicae infection on the microbial communities of soil, seeds, roots, and the rhizosphere in susceptible and resistant canola lines, with the aim of analyzing host–pathogen–microbiome interactions and identifying microbial taxa potentially associated with disease resistance. Our findings showed that resistant canola lines inoculated with P. brassicae (pathotype 3A) exhibited reduced disease severity compared to their susceptible counterparts. Diversity analyses of microbial communities revealed that clubroot-resistant canola lines tended to maintain more stable and diverse fungal communities, with a higher Shannon index than susceptible lines. Inoculation with P. brassicae induced more pronounced changes in the root microbiome than in the rhizosphere. Additionally, the seed microbiomes of resistant and susceptible lines displayed distinct bacterial and fungal profiles, suggesting that clubroot susceptibility may influence seed-associated microbial community composition. Differential abundance analysis of root and rhizosphere microbiomes indicated that certain microbial taxa, including bacterial genera such as Acidovorax, Bacillus, Cupriavidus, Cytophaga, Duganella, Flavobacterium, Fluviicola, Luteimonas, Methylotenera, Pedobacter, and Peredibacter, as well as fungal genera such as Aspergillus, Candida, Fusicolla, Paecilomyces, and Rhizophlyctis, may be recruited or enriched in resistant canola lines following P. brassicae inoculation, potentially contributing to reduced clubroot severity. Full article

Clubroot disease, caused by Plasmodiophora brassicae, poses a serious threat to global Brassica crop production. Orphan genes (OGs), which are species or lineage-specific and lack detectable homologs in other taxa, have been implicated in various biotic stress responses. Here, we identified a novel Brassica rapa-specific orphan gene, designated CROG1, that confers resistance to clubroot. Heterologous overexpression of CROG1 in Arabidopsis thaliana significantly enhanced resistance to P. brassicae. Transcriptomic profiling of CROG1-overexpressing lines highlighted the essential role of the phenylpropanoid biosynthesis pathway, showing upregulation of key lignin synthesis genes (including CCoAMT, CAD6, PER4, and AZI1) and defense-related regulators (RBOHC and WAKs). Weighted co-expression network analysis further corroborated the link between CROG1-mediated resistance and enhanced lignin deposition and cell wall reinforcement. Our findings establish CROG1 as a Brassica-specific orphan gene that enhances clubroot resistance via phenylpropanoid pathway activation. These results highlight the potential of orphan genes as novel genetic resources for breeding clubroot-resistant Brassica varieties, offering a sustainable strategy to mitigate yield losses caused by this devastating disease. Full article