Search Results (326)

Hyperspectral sensors have emerged as a promising approach in the study of plant diseases. The objective was to distinguish between healthy and inoculated seeds, and also to distinguish between genera of plant-pathogenic fungi in soybean seeds, using hyperspectral sensors combined with machine learning. The experimental design was a fully randomized factorial design with six algorithms (Simple Logistic Regression, Support Vector Machine, Artificial Neural Network, Random Forest, REPTree and J48 decision trees) and four phytopathogens (Sclerotinia sclerotiorum, Macrophomina phaseolina, Rhizoctonia solani, and Colletotrichum sp.) plus the control. Spectral analysis of the seeds was performed using a spectroradiometer (Ocean Optics) consisting of two sensors: NIR and Flame, covering the spectrum from 350 to 2500 nm. It was possible to distinguish between healthy and inoculated seeds, as well as identify the type of phytopathogen, based on each spectral signature. The Simple Logistic Regression and Support Vector Machine algorithms performed best. Hyperspectral sensors combined with machine learning constitute a promising tool for the detection of phytopathogens in seeds, enabling rapid and non-destructive analysis. This promising tool could serve as a complementary alternative to traditional diagnostic methods, which, although accurate, are time-consuming and rely on specialized labor. Full article

Sclerotinia sclerotiorum causes destructive sclerotinia stem rot and severe yield losses in global rapeseed production. The Bacillus biocontrol strain YZUS007 serves as an eco-friendly alternative to synthetic fungicides, yet its control efficacy fluctuates under complex field conditions. This study aimed to investigate whether low-dose ZnO NPs could enhance the biocontrol efficacy of YZUS007 and to elucidate the underlying mechanisms. We isolated and identified the antagonistic strain Bacillus siamensis YZUS007 from the rhizosphere soil of healthy Brassica napus, which exhibited an in vitro pathogen inhibition rate of 78.4 ± 0.7%. Pot tests showed that YZUS007 (BC) achieved 60.79% control efficacy, whereas the YZUS007 + 20 μg/mL ZnO NPs group (BZ) reached 74.68%. Cell-free filtrate of YZUS007 (EC) had a 50.44% control efficacy, and filtrate with ZnO NPs (EZ) increased efficacy to 58.08%. LC-MS/MS identified four extracellular metabolites with increased relative abundances: cinnamic acid, sesamol, patchouli alcohol and 2-phenylbutyric acid. The combined treatment boosted defense enzyme activities and induced higher expression of the defense-related genes RBOH, PR1 and WRKY33. Collectively, low-concentration ZnO NPs significantly enhanced the biocontrol performance of YZUS007 by promoting antifungal metabolite accumulation, providing a low-dose, nanomaterial-assisted strategy for sustainable sclerotinia rot management. Full article

Sclerotinia sclerotiorum is a broad-spectrum soilborne fungal pathogen, causing substantial yield losses in crops worldwide. Auxiliary Activity Family 5 (AA5) copper radical oxidases (CROs) are members of the carbohydrate active enzymes (CAZymes), valued for their potential as biocatalysts. Although they were reported to contribute to fungal development and disease progression in some phytopathogenic fungi such as Colletotrichum graminicola, the roles of AA5 enzymes in S. sclerotiorum remain largely unexplored. Here, we systematically investigated S. sclerotiorum AA5 genes through reverse genetics and biochemical approaches. Phylogenetic analysis grouped the S. sclerotiorum AA5 proteins into two subfamilies, including three subfamily 1 (AA5_1) members and one subfamily 2 (AA5_2) member. Enzymatic characterization revealed that one AA5_1 enzyme, SsAA5c, exhibited the highest catalytic specificity towards D-glyceraldehyde compared with methylglyoxal and glycerol. In addition, a predicted peroxidase gene (SsPX1) was identified in tandem with the putative AA5_2 gene, SsAA5d. Phenotypic analysis of gene deletion mutants demonstrated that these genes differentially affect fungal development and virulence. While their exact physiological substrates await identification, our findings highlight important roles of AA5 oxidases and the associated peroxidase in the biology of S. sclerotiorum, providing insights that may contribute to future improved disease management strategies. Full article

As a major fungal pathogen of Brassica napus, Sclerotinia sclerotiorum causes significant yield reductions worldwide. Receptor-like proteins (RLPs) are essential components of plant immunity, but the functions of many RLPs in B. napus still remain unclear. In this study, three BnaSOBIR1-interacting leucine-rich repeat RLPs (LRR-RLPs), named BnaRLP-G13-2, BnaRLP-G13-3, and BnaRLP-G13-4, were identified by yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays. Promoter analysis revealed diverse cis-acting elements involved in stress and phytohormone responses. Overexpression of these genes significantly improved resistance to S. sclerotiorum in both Arabidopsis thaliana and B. napus. Consistently, BnaRLP-G13-2/3/4 restored disease resistance and NLP-induced ROS production in the rlp23-1 mutant. Furthermore, BiFC assays suggested an association between BnaRLP-G13-2/3/4 and Ssnlp24_SsNEP2-associated perception, although direct biochemical binding remains to be demonstrated. These findings advance the understanding of BnaSOBIR1-associated BnaRLP-G13-2/3/4-mediated immunity and provide new insights into enhancing disease resistance in oilseed crops. Full article

Endophytic bacteria of the Bacillus subtilis species complex are known for plant growth promotion and antifungal activity, although strain-specific traits remain poorly understood. This study characterized the Bacillus siamensis strain BACIII, isolated from asymptomatic soybean roots in a charcoal rot-affected area, using whole-genome analysis and phenotypic assays. Genome sequencing identified BACIII as Bacillus siamensis and revealed a metabolically versatile genome containing twelve biosynthetic gene clusters linked to antimicrobial compounds such as difficidin, fengycin, and surfactin. Additionally, genomic islands associated with mobile elements, regulation, and stress response suggest adaptive potential. Inoculation with the BACIII strain significantly accelerated germination and increased early growth, biomass accumulation, and chlorophyll content in soybean and sunn hemp (p < 0.05), whereas no significant effects were observed in cotton or sunflower, indicating host-dependent responses. In vitro assays demonstrated consistent inhibition of several phytopathogenic fungi, including Sclerotinia sclerotiorum, Fusarium spp., and Macrophomina phaseolina, with variable intensity. Overall, BACIII combines host-specific plant growth promotion with broad antifungal activity, supporting its potential for biological control in sustainable agriculture. Full article

Salvia somalensis Vatke is a source of specialized metabolites with potential biological and agrochemical applications. Previous studies on the dichloromethane plant surface extract demonstrated strong antifungal activity associated with abietane diterpenoids. Building on these findings, the present study aimed to characterize the methanolic extract of S. somalensis and evaluate its antifungal potential against major phytopathogenic fungi, with the broader goal of exploring the extract as a sustainable source of antifungal metabolites for crop protection. LC-MS analysis of the methanolic extract revealed a diverse phytochemical profile comprising phenolic acids, including caffeic acid, ferulic acid, and rosmarinic acid, as well as abietane-type diterpenoids such as carnosol, rosmanol, and carnosic acid. Quantitative analysis showed that carnosic acid was present only at low levels (0.09% w/w of fresh biomass). The extract exhibited antifungal activity against Botrytis cinerea, Colletotrichum coccodes, Fusarium oxysporum, Rhizoctonia solani, and Sclerotinia sclerotiorum. More than 80% inhibition of mycelial growth was observed against B. cinerea and C. coccodes at 1000 μg/mL. In addition, as in vitro cultivation of this species has not previously been explored, micropropagated plants and callus culture were established. Phytochemical profiling revealed distinct chemical compositions in the in vitro biomass. Extracts obtained from micropropagated plants inhibited mycelial growth of the tested phytopathogens by 60–70% at 1000 μg/mL, except for F. oxysporum, which showed 35.29% inhibition at the same concentration. Collectively, these findings highlight S. somalensis as a source of bioactive metabolites with antifungal potential. Full article

Receptor-like cytoplasmic kinases (RLCKs) constitute a core family of signaling proteins that modulate diverse cellular activities and participate in multiple physiological and biochemical processes in plants. As a unique subclade of RLCKs, the receptor-like cytoplasmic kinases VII (RLCK VII) subfamily features a conserved kinase domain but lacks extracellular and transmembrane domains, and has been proven to exert crucial functions in plant immunity, growth and development, and yield formation. Background/Objectives: This study systematically identified and characterized RLCK VII family genes in the rapeseed (Brassica napus) genome, and explored their biological functions in plant resistance to Sclerotinia sclerotiorum. Methods: Multiple bioinformatics databases and online tools were employed to conduct a comprehensive analysis of the identified BnaRLCK VII genes, including their physicochemical properties, signal peptide characteristics, subcellular localization, phylogenetic relationships, gene structure, conserved motifs and domains, cis-regulatory elements, tissue-specific expression patterns, and gene duplication events. Transcriptome profiling (RNA-seq) and transient overexpression assays in Nicotiana tabacum were further performed to verify the function of BnaRLCK VII genes in S. sclerotiorum resistance. Results: A total of 173 RLCK VII family members were identified from the B. napus genome and designated as BnaRLCK VII genes. These genes were clustered into 10 distinct subgroups based on phylogenetic analysis. We further comprehensively analyzed their gene structures, conserved motifs, cis-acting elements, duplication patterns, and tissue expression profiles. RNA-seq analysis revealed that 31 BnaRLCK VII genes were significantly differentially expressed following S. sclerotiorum infection. Among these differentially expressed genes (DEGs), a homolog of Arabidopsis thaliana BIK1 was selected for functional validation and named BnaBIK1. Agrobacterium-mediated transient infiltration assays on tobacco leaves demonstrated that overexpression of BnaBIK1 could improve plant tolerance to S. sclerotiorum, which indicates that BnaBIK1 is a promising candidate gene for regulating rapeseed resistance against this pathogen. Conclusions: Collectively, these findings indicate that BnaRLCK VII family genes, particularly BnaBIK1, serve as key positive regulators of S. sclerotiorum resistance in B. napus. Full article

Microbial biocontrol agents often exhibit limited shelf life, which restricts their commercialization, storage, and large-scale agricultural application. In this study, freeze-drying (FD) microencapsulation was evaluated as a strategy to improve the stability of a wettable powder (WP) formulation based on Bacillus subtilis fermented broth using maltodextrin (MD) as a carrier. The physicochemical, structural, morphological, and antifungal properties of the resulting formulation were characterized. Physical characterization revealed complete solubility (100% at 0.1 g mL⁻¹), rapid wettability (2 s), and low hygroscopicity (3.86%), indicating favorable properties for handling and application. Scanning electron microscopy revealed irregular glass-like particles of different sizes, while Fourier transform infrared spectroscopy indicated the distribution of components within the maltodextrin matrix. The antifungal activity of the WP and the effects of its volatile organic compounds (VOCs) were evaluated against the phytopathogenic fungi Fusarium oxysporum, Fusarium solani, Fusarium graminearum, Rhizoctonia solani, and Sclerotinia sclerotiorum. The formulation inhibited fungal growth within the tested concentration range (0.1–0.2 g mL⁻¹), although no clear inhibition zone was observed for S. sclerotiorum. Furthermore, the WP maintained 65% viability after 24 months of storage at 4 °C. These results demonstrate the potential of FD microencapsulation to enhance the storage stability of Bacillus subtilis formulations while preserving their antifungal activity. 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

Sclerotinia sclerotiorum is a formidable soilborne fungus that wreaks havoc on numerous crops globally. While the role of ADP-ribosylation factor-like 1 (Arl1) small GTPases in vesicular trafficking and fungal development is well-documented, their specific impact on S. sclerotiorum remains unclear. Through reverse genetic techniques, we identified and characterized SsArl1, a typical Arl small GTPase conserved across fungi. Deleting SsArl1 hampers the hyphal growth of S. sclerotiorum, but leads to higher oxalic acid buildup and boosts cellulase activity. This speeds up the infection of host plants, yet increases their sensitivity to certain environmental stresses, particularly ionic and cell wall-related stress. Our results reveal that SsArl1 acts as a negative regulator of oxalic acid accumulation and virulence, while playing a positive role in enhancing resistance to environmental stresses in S. sclerotiorum. Full article

Necrosis- and ethylene-inducing peptide 1 (Nep1)-like proteins (NLPs) are conserved microbial proteins that contain immunogenic patterns capable of activating plant pattern-triggered immunity (PTI). NLP patterns from Sclerotinia sclerotiorum (SsNLPs), a destructive necrotrophic fungal pathogen with a broad host range, have been identified, and their roles in PTI have been revealed. Nevertheless, the molecular mechanisms by which SsNLPs stimulate plant immunity remain largely unknown. In this study, we phylogenetically characterized SsNLPs and demonstrated the involvement of the phytocytokine receptor-like kinases PEPRs in SsNLP1-triggered immunity. SsNLPs contained the NPP1 domain and GHRHDWE motif and were phylogenetically closely associated with Botrytis cinerea NLPs. SsNLP1 treatment strongly induced the expression of PEPR genes. Further genetic analyses using Arabidopsis wild-type, pepr1 pepr2 double mutant, and PEPR1 overexpression lines showed that SsNLP1 elicited diverse immune responses, including reactive oxygen species (ROS) accumulation and defense gene activation, and induced plant resistance to S. sclerotiorum. Notably, the induced plant resistance and immune responses were strengthened in PEPR1 overexpression lines and significantly reduced in the pepr1 pepr2 mutant, indicating a positive role of PEPR signaling in SsNLP1-triggered immunity. Overall, our results revealed that phytocytokine PEPR1 signaling amplifies PAMP SsNLP1-triggered immunity, thereby enhancing resistance against S. sclerotiorum. Our findings provide an example of the coordination between PAMP- and phytocytokine-triggered immunity for robust resistance to a necrotrophic pathogen. 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

Plant hormones and their synthetic analogueues offer sustainable alternatives for crop protection, yet the direct antifungal activity of strigolactone (SL) and its analogues against necrotrophic pathogens remain largely unexplored. Here, we screened eight phytohormones and related analogues for treatments of Botrytis cinerea and identified the SL analogue rac-GR24 (racemic GR24) as a concentration-dependent growth inhibitor active at low micromolar concentrations. Given the stereochemical complexity of SLs and their analogues, we evaluated multiple enantiopure isomers and found that ent-5DS and GR24^ent-5DS, which differ in configuration from natural SLs, exhibited the strongest inhibitory activity. This stereospecific response was further validated using another filamentous fungus, Sclerotinia sclerotiorum, which displayed an identical susceptibility profile. Combinatorial treatments with enantiopure isomers and double-concentration rac-GR24 revealed that the antifungal effect of the racemate is primarily attributable to the GR24^ent-5DS enantiomer, whereas the opposite enantiomer GR24^5DS is almost inactive. Collectively, our findings uncover a stereospecific response in fungal pathogens, demonstrating that B. cinerea and S. sclerotiorum respond to exogenous SL analogues in a chirally selective manner. This work establishes a stereochemically defined framework for developing enantioselective fungicidal agents with potential applications in sustainable agriculture. Full article

The necrotrophic pathogen Sclerotinia sclerotiorum compromises the physiological and anatomical integrity of cotton, leading to substantial economic losses due to rapid tissue necrosis, stem blight, boll rot, and leaf wilting. In this context, the use of endophytic microorganisms emerges as a promising strategy for the biocontrol of white mold. This study tested the hypothesis that endophytic fungal strains isolated from the roots of Butia purpurascens, a palm tree endemic to the Cerrado biome, could mitigate disease symptoms in Gossypium hirsutum L. To evaluate this, cotton plants were subjected to biotic stress imposed by S. sclerotiorum to assess the effectiveness of seven fungal strains in attenuating disease. The impact of the pathogen was monitored through growth variables, gas exchange, leaf temperature, chlorophyll a fluorescence, antioxidant enzyme activity, proline and malondialdehyde (MDA) levels, and the incidence of rot in petioles, leaves, and flower buds. Overall, inoculation with endophytic fungi significantly alleviated the effects of the phytopathogen, promoting vegetative growth and optimizing physiological performance. Treated plants exhibited alleviated stress in primary photochemistry, reduced non-photochemical energy dissipation, and stable carbon fixation. Additionally, efficient modulation of the antioxidant system and preservation of anatomical structures were observed, minimizing the severe symptoms of white mold. Notably, the non-pathogenic strains BP10EF (Gibberella moniliformis), BP16EF (Penicillium purpurogenum), and BP33EF (Hamigera insecticola) acted as potent physiological modulators, yielding responses similar to those of healthy plants. These results highlight the biotechnological potential of these endophytic strains, which can be explored as both growth promoters and resistance inducers in cotton against white mold. Full article

Traditional disease management, which is based on the application of synthetic chemical products, has negatively affected human health and the environment. A sustainable approach based on the application of natural compounds and microorganisms is potentially better for consumer health. Thus, the aim of this study was to evaluate the efficacy of plant-based and/or organic products against soilborne fungal pathogens of tomato. A preliminary in vitro experiment was performed to select potential putative inhibitory products (PIPs) and fungal pathogens that were then used in an in vivo experiment conducted inside a greenhouse that mimics real-world field conditions. For the greenhouse experiment, bergamot and pomegranate wastes and the commercial product EP5 were selected as the PIPs to control Agroathelia rolfsii, Fusarium oxysporum and Sclerotinia sclerotiorum growth. Each pot was artificially inoculated three days before the low-dose treatment, and one tomato seedling was transplanted into each pot four days after the treatment. Data regarding the phytosanitary status of the plants and roots, as well as their length and weight, were collected after 45 days, and the results obtained demonstrate that plant-derived products were able to mitigate fungal diseases, with pomegranate waste being the most effective. Also, the EP5 product, as a resistant inducer, was able to significantly improve the natural defense of tomato plants, resulting in it being the best PIP used. Mycological analyses were performed on the roots to assess the presence of inoculated fungal pathogens after natural product treatment. Overall, the results confirm that the PIPs are suitable for crop management, but the outcomes are variable. In general, pomegranate waste and EP5 significantly protected the roots against fungal attacks, while bergamot waste showed lower efficacy. This trend was not observed for plant length and weight, as the treated plants showed results similar to those of the untreated controls. In conclusion, natural products are a valid alternative to chemicals, as they demonstrate both efficacy and safety, but their potential should be further investigated in field trials. Full article