Disruption of the Gene Encoding Endo-β-1, 4-Xylanase Affects the Growth and Virulence of Sclerotinia sclerotiorum

Sclerotinia sclerotiorum (Lib.) de Bary is a devastating fungal pathogen with worldwide distribution. S. sclerotiorum is a necrotrophic fungus that secretes many cell wall-degrading enzymes (CWDEs) that destroy plant’s cell-wall components. Functional analyses of the genes that encode CWEDs will help explain the mechanisms of growth and pathogenicity of S. sclerotiorum. Here, we isolated and characterized a gene SsXyl1 that encoded an endo-β-1, 4-xylanase in S. sclerotiorum. The SsXyl1 expression showed a slight increase during the development and germination stages of sclerotia and a dramatic increase during infection. The expression of SsXyl1 was induced by xylan. The SsXyl1 deletion strains produce aberrant sclerotia that could not germinate to form apothecia. The SsXyl1 deletion strains also lost virulence to the hosts. This study demonstrates the important roles of endo-β-1, 4-xylanase in the growth and virulence of S. sclerotiorum

Thlaspi arvense suppresses gut microbiota related TNF inflammatory pathway to alleviates ulcerative colitis

IntroductionThlaspi arvense (TA), commonly known as “Ximi” or “Subaijiang,” is a traditional Chinese medicinal herb used to prevent and treat ulcerative colitis (UC). However, the precise mechanisms underlying its therapeutic effects remain unclear, necessitating further investigation to identify potential pharmaceutical applications for UC management. This study aims to elucidate the efficacy and mechanisms of TA and its active constituents in UC treatment.MethodsThis study first evaluated the effects of varying TA doses on 3% dextran sulfate sodium (DSS)-induced UC. Gut microbiota alterations in UC mice were analyzed via 16S rRNA sequencing, with correlation analyses to reveal the relationship between gut microbiota and cytokines. Then, network pharmacology was utilized to identified potential TA targets for UC treatment. Protein-protein interaction (PPI) networks, Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were employed to explore TA’s mechanisms. Molecular docking and dynamics simulations validated interactions between TA’s active compounds and UC-related targets. Finally, TNF pathway modulation by TA and its active component, isovitexin, was verified in vitro and in vivo.ResultsTA alleviated DSS-induced weight loss in a dose-dependent manner, reduced disease activity indices, and preserved intestinal mucosal barrier integrity. Subsequently, fluorescence in situ hybridization (FISH) revealed TA suppressed microbial translocation in intestinal tissues. To further characterize inflammatory responses, ELISA demonstrated that TA modulated levels of key cytokines (TNF-α, IL-1β, IL-6, IL-10) and oxidative stress markers (SOD, MDA), indicating systemic anti-inflammatory effects. Building on these findings, 16S rRNA sequencing analyses showed that TA regulated gut microbiota alpha/beta diversity and inhibited infectious disease-related pathways. Notably, correlation heatmaps highlighted a strong association between TNF-α levels and Escherichia-Shigella abundance, with high-dose TA significantly reducing this pathogenic bacterial genus. To systematically explore molecular mechanisms, network pharmacology identified 220 potential TA targets for UC treatment. Consistent with experimental data, PPI and KEGG analyses implicated TNF-α, IL-6, and AKT as key targets, primarily through TNF signaling pathway modulation. To validate these predictions, molecular docking confirmed stable interactions between TA compounds and identified targets, while dynamics simulations specifically emphasized isovitexin’s high affinity for TNF-α. Finally, experiments in vivo demonstrated TA’s inhibition of TNF-α-mediated NF-κB pathway activation, and in vitro studies confirmed that isovitexin directly mitigated TNF-α-induced intestinal epithelial damage. Furthermore, TA demonstrated potent inhibition of TNF-α-mediated NF-κB inflammatory pathway activation in intestinal tissues, while its active constituent isovitexin effectively mitigated TNF-α-induced epithelial cell damage, collectively highlighting their complementary anti-inflammatory mechanisms.DiscussionCollectively, Thlaspi arvense (TA) ameliorates ulcerative colitis through synergistic mechanisms involving gut microbiota modulation, inflammatory pathway suppression, and intestinal barrier preservation. By remodeling microbial communities to reduce Escherichia-Shigella colonization and microbial translocation. TA concurrently inhibits TNF-α/NF-κB-driven inflammation, and oxidative stress regulation. Furthermore, its active constituent isovitexin directly attenuates TNF-α-induced epithelial damage, demonstrating multi-scale therapeutic efficacy. These findings establish TA’s multi-target pharmacology spanning host-microbe interactions and intracellular signaling, while providing a rationale for standardizing TA-based formulations and advancing isovitexin as a precision therapeutic agent for inflammatory bowel diseases

Sclerotinia sclerotiorum Thioredoxin Reductase Is Required for Oxidative Stress Tolerance, Virulence, and Sclerotial Development

Sclerotinia sclerotiorum is a destructive ascomycete plant pathogen with worldwide distribution. Extensive research on different aspects of this pathogen’s capability to cause disease will help to uncover clues about new ways to safely control Sclerotinia diseases. The thioredoxin (Trx) system consists of Trx and thioredoxin reductase (TrxR), which play critical roles in maintenance of cellular redox homeostasis. In this study, we functionally characterized a gene encoding a TrxR (SsTrr1) in S. sclerotiorum. The amino acids of SsTrr1 exhibited high similarity with reported TrxRs in plant pathogens and targeted silencing of SsTrr1 lead to a decrease in TrxR activities of mycelium. SsTrr1 showed high expression levels during hyphae growth, and the levels decreased at the different stages of sclerotial development. SsTrr1 gene-silenced strains produced a smaller number of larger sclerotia on potato dextrose agar medium. The observations were consistent with the inhibitory effects on sclerotial development by the TrxR inhibitor, anrunofin. The expression of SsTrr1 showed a dramatic increase under the oxidative stress and the hyphal growth of gene-silenced strains showed more sensitivity to H2O2. SsTrr1 gene-silenced strains also showed impaired virulence in different hosts. Taken together, our results suggest that SsTrr1 encodes a TrxR that is of great important for oxidative stress tolerance, virulence, and sclerotial development of S. sclerotiorum

Genome-Wide Identification of the RhoGAP Gene Family and Main Function of OsRhoGAP2 in Seed Germination of Rice by Transcriptome Analysis

Abstract Rho GTPase-activating proteins (RhoGAPs) play crucial roles in regulating various biological processes. However, the functions of RhoGAP family genes in rice (Oryza sativa) remain largely unexplored. Here, we identified 19 RhoGAP genes in rice, and preliminarily analyzed the genes information, expression patterns, and evolutionary relationship with AtRhoGAPs in Arabidopsis. Using CRISPR/Cas9-mediated gene editing, we generated loss-of-function mutants of OsRhoGAP2 (rhogap2) and found that seed germination was significantly delayed compared to the wild type (WT). Further analysis revealed that α-amylase activity was reduced in rhogap2 germinating seeds. RNA-seq profiling identified 291 upregulated and 130 downregulated genes in the mutant, with differentially expressed genes (DEGs) primarily enriched in phenylpropanoid biosynthesis and other metabolic pathways. Notably, most phenylpropanoid biosynthesis-related genes exhibited increased expression in rhogap2 germinating seeds. These findings establish a foundational framework for future functional studies of RhoGAP genes in rice and provide novel insights into the molecular mechanisms by which RhoGAPs regulate seed germination in plants

Loop-Mediated Isothermal Amplification for the Rapid Detection of the Mutation of Carbendazim-Resistant Isolates in <i>Didymella bryoniae</i>

Gummy stem blight (GSB) caused by Didymella bryoniae (D. bryoniae) is a worldwide fungal soil-borne disease that can cause severe yield reduction of watermelon. To shorten the monitoring time of carbendazim-resistant strains of D. bryoniae in the field, in this study, we developed a loop-mediated isothermal amplification (LAMP) assay for rapid detection of carbendazim-resistant strains of D. bryoniae. The β-tubulin gene of carbendazim-resistant strains was selected as the target for primer design. Based on the color change of hydroxy naphthol blue (HNB) and gel electrophoresis, the optimal reaction conditions for LAMP were determined at 65 °C for 50 min. In specificity tests, the LAMP assay was able to distinguish between carbendazim-resistant and sensitive strains of D. bryoniae. Moreover, in sensitivity tests, the detection limit was 1 ng/μL D. bryoniae DNA of the carbendazim-resistant strain. In addition, the LAMP method was successfully applied to detect carbendazim-resistant strains in D. bryoniae-infested samples. Therefore, the developed LAMP assay provides a new method for the rapid detection of carbendazim-resistant strains of D. bryoniae

A Comparative Study on the Degradation Behaviors of Ferroelectric Gate GaN HEMT with PZT and PZT/Al2O3 Gate Stacks

In this paper, the degradation behaviors of the ferroelectric gate Gallium nitride (GaN) high electron mobility transistor (HEMT) under positive gate bias stress are discussed. Devices with a gate dielectric that consists of pure Pb(Zr,Ti)O3 (PZT) and a composite PZT/Al2O3 bilayer are studied. Two different mechanisms, charge trapping and generation of traps, both contribute to the degradation. We have observed positive threshold voltage shift in both kinds of devices under positive gate bias stress. In the devices with a PZT gate oxide, we have found the degradation is owing to electron trapping in pre-existing oxide traps. However, the degradation is caused by electron trapping in pre-existing oxide traps and the generation of traps for the devices with a composite PZT/Al2O3 gate oxide. Owing to the large difference in dielectric constants between PZT and Al2O3, the strong electric field in the Al2O3 interlayer makes PZT/Al2O3 GaN HEMT easier to degrade. In addition, the ferroelectricity in PZT enhances the electric field in Al2O3 interlayer and leads to more severe degradation. According to this study, it is worth noting that the reliability problem of the ferroelectric gate GaN HEMT may be more severe than the conventional metal&ndash;insulator&ndash;semiconductor HEMT (MIS-HEMT)