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Azoxystrobin, a quinone outside inhibitor fungicide, reduced tobacco target spot caused by Rhizoctonia solani by 62%, but also affected the composition and diversity of other microbes on the surface and interior of treated tobacco leaves. High-throughput sequencing showed that the dominant bacteria prior to azoxystrobin treatment were Methylobacterium on healthy leaves and Pseudomonas on diseased leaves, and the dominant fungi were Thanatephorous (teleomorph of Rhizoctonia ) and Symmetrospora on healthy leaves and Thanatephorous on diseased leaves. Both bacterial and fungal diversity significantly increased 1 to 18 days post treatment (dpt) with azoxystrobin for healthy and diseased leaves. For bacteria on healthy leaves, the relative abundance of Pseudomonas , Sphingomonas, Unidentified-Rhizobiaceae and Massilia declined, while Methylobacterium and Aureimonas increased. On diseased leaves, the relative abundance of Sphingomonas and Unidentified-Rhizobiaceae declined, while Methylobacterium, Pseudomonas and Pantoea increased. For fungi on healthy leaves, the relative abundance of Thanatephorous declined, while Symmetrospora , Sampaiozyma , Plectosphaerella , Cladosporium and Cercospora increased. On diseased leaves, the relative abundance of Thanatephorous declined, while Symmetrospora , Sampaiozyma , Plectosphaerella , Cladosporium , Phoma , Pantospora and Fusarium , increased. Compared to healthy leaves, azoxystrobin treatment of diseased leaves resulted in greater reductions in Thanatephorous , Sphingomonas and Unidentified-Rhizobiaceae , a greater increase in Methylobacterium , and similar changes in Phoma, Fusarium , Plectosphaerella and Cladosporium . Azoxystrobin had a semi-selective effect altering the microbial diversity of the tobacco leaf microbiome, which could be due to factors, such as differences among bacterial and fungal species in sensitivity to quinone outside inhibitors, ability to use nutrients and niches as certain microbes are affected, and metabolic responses to azoxystrobin.

Tobacco target spot disease is caused by a ubiquitous soil-borne phytopathogen Rhizoctonia solani ; the pathogenic mechanisms underlying the effects of R. solani remain unclear. Deeper understanding of the functional responses to R. solani during host plant infection would help identify the molecular mechanisms essential for successful host invasion. In this study, we performed global transcriptional analysis of R. solani during various stages (12, 24, 48, 72, 96, and 120 h) of tobacco infection via an RNA sequencing method, while utilizing the pathosystem model R. solani AG3–tobacco ( Nicotiana tabacum L.). After R. solani inoculation, the number of differentially expressed genes of R. solani differed at the various time points. Moreover, several gene ontology and Kyoto encyclopedia of genes and genomes pathways were unique in different infection stages, especially with respect to the genes involved in plant cell wall degradation and catalysis of biotransformation reactions, such as the pectin metabolic process and pectin catabolic process. The overexpressing-PD8 N. benthamiana plants enhanced the susceptibility to R. solani. In addition, we found that large amounts of reactive oxygen species (ROS) were generated in tobacco after infected by R. solani . R. solani encoding FAD/NAD binding oxidoreductase and peroxidase gene family to eliminating ROS and counteract oxidative stress. Moreover, Perox3 was validated that can enhance the ability of scavenging ROS by co-injecting. Overall, our findings show that pectin-degrading enzymes and cytochrome P450 genes are critical for plant infection. These results provide comprehensive insights into R. solani AG3 transcriptome responses during tobacco invasion.

Spatial infrared spot target (SIST) discrimination based on infrared radiation sequences (IRSs) can be considered a univariate trending time series classification task. However, due to the complexity of actual scenarios and the limited opportunities for acquiring IRSs, resulting in noise interference, extremely small-scale datasets with imbalanced distribution of classes and widely varying sequence lengths range from a few hundred to several thousand time steps. Current research is primarily based on idealized simulation datasets, resulting in a performance gap when applied to actual applications. To address these issues, firstly, we construct a simulation dataset tailored to the challenges of actual scenarios. Secondly, we design a practical data preprocessing method to achieve uniform sequence length, coarse alignment of shapelets and filtering while preserving key points. Thirdly, we propose a residual network Res-LK-SLR for IRS classification based on large kernels (LKs, providing long-term dependence) and shapelet-level representations (SLRs, where the hidden layer features are aligned with the learned high-level representations to obtain the optimal segmentation and generate shapelet-level representations). Additionally, we conduct extensive evaluations and validations on both the simulation dataset and 18 UCR time series classification datasets. The results demonstrate the effectiveness and generalization ability of our proposed Res-LK-SLR.

Fungal diseases form perforated disease spots in tobacco plants, resulting in a decline in tobacco yield and quality. The present study investigated the antagonistic effect of CTXW 7-6-2 against , its ability to promote the growth of tobacco seedlings, and the expression of disease resistance-related genes for efficient and eco-friendly plant disease control. Our results showed that CTXW 7-6-2 had the most vigorous growth after being cultured for 96 h, and its rate of inhibition of growth was 94.02%. The volatile compounds produced by CTXW 7-6-2 inhibited the growth of significantly (by 96.62%). The fungal growthinhibition rate of the CTXW 7-6-2 broth obtained after high-temperature and no-high-temperature sterile fermentation was low, at 50.88% and 54.63%, respectively. The lipopeptides extracted from the CTXW 7-6-2 fermentation broth showed a 74.88% fungal growth inhibition rate at a concentration of 100 mg/l. Scanning and transmission electron microscopy showed some organelle structural abnormalities, collapse, shrinkage, blurring, and dissolution in the mycelia. In addition, CTXW 7-6-2 increased tobacco seedling growth and improved leaf and root weight compared to the control. After CTXW 7-6-2 inoculation, tobacco leaves showed the upregulation of the , , and genes, which are closely related to target spot disease resistance. In conclusion, CTXW 7-6-2 may be an efficient biological control agent in tobacco agriculture and enhance plant growth potential.

Rhizoctonia solani AG-3 TB primarily causes tobacco target spot disease by producing a large number of sexual spores. However, inducing sexual spore formation under in vitro conditions has been challenging, impeding further research on its control. In this study, field experiments were conducted to assess the effects of different concentrations of chemical and biological fungicides on the production of sexual spores of R. solani AG-3 TB on tobacco plants. The results demonstrated that four chemical fungicides (propiconazole-morpholine guanidine, bordeaux mixture, thiophanate-methyl, and mancozeb) significantly induced sexual spore formation. Among them, increasing the concentrations of the first three fungicides resulted in an increase in the number of sexual spores, while increasing the concentration of mancozeb led to a decrease in spore count. The pathogenic fungus produced more sexual spores during the night than during the day. Temperature, humidity, and light conditions influenced spore production. Additionally, the infection rate of sexual spores was directly proportional to their concentration and inoculation time, but their survival time did not exceed 6 h in vitro. Importantly, Streptomyces rectiolaceus A8 significantly suppressed sexual spore formation, achieving an 83.63% control efficacy in the field and producing antimicrobial substances against R. solani AG-3 TB. In conclusion, appropriate concentrations of chemical fungicides can induce sexual spore formation, while A8 can inhibit their production, showing potential value for controlling tobacco target spot disease.

Target leaf spot disease (TLS), caused by Corynespora cassiicola (Berk & Curt) Wei, ranks among the most serious fungal diseases affecting cucumber production. However, the genetic basis for TLS resistance in cucumber has not yet been determined. In this study, we evaluated TLS resistance in the adult plants of 130 cucumber accessions using a disease index (DI) in October 2021, June 2023, and October 2023. The accessions used in this study were representative collection selected from the global 3,342 accessions, and contain four ecotypes (the Eurasian, Indian, East Asian, and Xishuangbanna type). Cluster analysis suggested that 11 of the 130 accessions exhibited high levels of TLS resistance (CG28, CG70, CG84, CG86, CG100, CG104, CG98, R163, R61, CG64, CG71). A genome-wide association study (GWAS) analysis was then performed based on the BLUP value of the DI collected from these three seasons, and three loci ( gTLS5.1 , gTLS5.2 , and gTLS7.1 ) associated with TLS on two chromosomes were identified. Seven candidate genes linked to disease resistance and abiotic stress were identified through functional annotation with Arabidopsis orthologous genes and pairwise linkage disequilibrium (LD) correlation analysis. Sequence alignment, expression and haplotype analysis further indicated to five of these candidate genes as being potentially causal to TLS: CsaV3_5G010580 for gTLS5.1 , and CsaV3_7G026140, CsaV3_7G026180 , CsaV3_7G026200 and CsaV3_7G026220 for gTLS7.1 . These genes related to TLS resistance in cucumber, could be useful to promote cucumber breeding and development.

Background Cucumber downy mildew, caused by P. cubensis , is an important leaf disease that can severely affect cucumber production. In recent years, cucumber target spot, caused by C. cassiicola , has been reported in both Asia and Europe and is now considered as a major disease disrupting cucumber production. Single-disease-resistant cucumber varieties have been unable to satisfy production needs. To explore the molecular mechanisms of cucumber resistance to these two diseases, cucumber cultivars D9320 (resistant to downy mildew and target spot) and D0401 (susceptible to downy mildew and target spot) were used as experimental materials in this study. We used transcriptome sequencing technology to identify genes related to disease resistance and verified using transgenic technology. Results We screened out the cucumber resistance-related gene CsERF004 using transcriptome sequencing technology. Induction by pathogens, salicylic acid (SA), and ethylene (ET) resulted in the up-regulation of CsERF004 . Three treatments, namely, inoculation with C. cassiicola alone, inoculation with P. cubensis alone, and simultaneous inoculation with both pathogens, all resulted in the significant and sustained up-regulation of CsERF004 in the resistant cultivar D9320, during the early stage of infection. In the susceptible cultivar D0401, CsERF004 expression was also significantly up-regulated at the later stage of infection but to a lesser extent and for a shorter duration than in the resistant cultivar D9320. The CsERF004 gene encodes a protein localizes to the nucleus. The over-expression of CsERF004 in the susceptible cultivar D0401 resulted in the significant up-regulation of the CsPR1 and CsPR4 genes and increased the levels of SA and ET, which enhanced the resistance of cucumber to downy mildew and target spot. Conclusions Analyses of the CsERF004 expression pattern in disease-resistant and susceptible cucumber cultivars and transgenic validation indicate that CsERF004 confers resistance to P. cubensis and C. cassiicola . The findings of this study can help to better understanding of mechanisms of response to pathogens and in establishment the genetic basis for the development of cucumber broad-spectrum resistant cultivars.

Point mutation G143A in the cytochrome b (Cyt b) protein commonly confers resistance to quinone outside inhibitor (QoI) fungicides in phytopathogenic fungi, including Corynespora cassiicola, which causes cucumber target spot disease. However, the effect of G143A on the binding between the QoI fungicide and the Cyt b protein, and the use of LAMP (loop-mediated isothermal amplification) to detect this point mutation had not been reported previously in C. cassiicola. In this study, the sensitivity of 131 C. cassiicola isolates—collected from Shandong province, China in 2019 and 2020—to pyraclostrobin was determined. The EC50 values ranged from 1.67 to 8.82 μg/mL, and sequencing results showed that all C. cassiicola isolates contained the G143A mutation. Molecular docking results suggested that G143A significantly alters the affinity of pyraclostrobin to the Cyt b protein. Following development of three LAMP primer pairs, the best reaction condition for LAMP analysis was 65 °C for 60 min, and the detection limit was 0.01 ng/μL of DNA containing the point mutation. In conclusion, the G143A mutation conferring pyraclostrobin resistance is widespread in C. cassiicola from Shandong province, and the LAMP method can be used to monitor QoI resistance in C. cassiicola caused by the G143A mutation in the field.

Objectives Rhizoctonia solani AG-3 is the casual pathogen of tobacco target spot, a serious fungal disease of tobacco that severely decreases yield and quality. To examine the pathogenic mechanisms of this fungus, it is crucial to understand its genetics. The objective of this work was to generate the first fine mapping of a R. solani AG-3 strain from tobacco and to explore potential virulence genes, which will lay the foundation for genetic characterization and its interaction with tobacco. The functional genes involved in this study can be used as the candidates for follow-up experimental analyses. Data description Rhizoctonia solani AG-3 strain XEMS25-1 was isolated from disease leaves of tobacco target spot in Enshi, Hubei Province, China. The DNA was sequenced using Pacific Biosciences Sequel II (PacBio) and Illumina NovaSeq PE150 (Nova). Data from both sequencing platforms were combined, and the de novo assembly yielded an estimated 39.4 Mb genome. Completeness of the genome examined using Benchmarking Universal SingleCopy Orthologs (BUSCO) showed that the assembly had 93.7% of the 758 genes in fungi_odb10. PHI (Pathogen Host Interactions) database analysis revealed 519 reduced virulence genes, 91 loss of pathogenicity genes, 28 hypervirulence genes and 18 effectors might be the pathogenicity-related genes in R. solani AG-3 strain XEMS25-1. These genes could be selected as the RNA-silencing targets for exploring the molecular mechanisms of R. solani AG-3 pathogenicity on tobacco.

In this work we present a novel biostimulant for sustainable crop disease management named PSP1. PSP1 is based on the plant defense-elicitor AsES, an extracellular protease produced by the strawberry fungal pathogen Acremonium strictum. Fungal fermentation conditions and downstream processing were determined to maximize extracellular protein production, product stability and a high plant defense-eliciting activity, as monitored by anthracnose resistance in supernatant-treated strawberry plants subsequently infected with a viral strain of Colletotrichum acutatum. Fermentation batches were shown to reduce anthracnose development by 30 to 60% as compared to infected non-treated plants. Product formulation was shown to be stable for 6 months when stored at temperatures up to 45°C and toxicological tests showed that PSP1 was harmless to beneficial organisms and non-toxic to mammalian species at concentrations 50 times higher than those used in plant experiments. Furthermore, disease protection studies using dilutions of PSP1 indicated that there is a minimum threshold protease activity needed to induce pathogen defense in strawberry and that this induction effect is dose-independent. A significant characteristic of PSP1 is its broad-range protection against different diseases in various crop species. In soybean, PSP1 reduced the symptomatology by 70% of Corynespora cassiicola, etiological agent of the target spot. This protection effect was similar to the commercial inducer BION 500 WG based on BTH, and both products were shown to induce an oxidative burst and up-regulated PR1-gene expression in soybean. Furthermore, a double PSP1-treatment on greenhouse-grown sugarcane plants provided protection against bacterial red stripe disease caused by Acidovorax avenae and a double foliar application of PSP1 on field-grown wheat plants significantly increased resistance against Fusarium graminearum, causal agent of head blight disease, manifested mainly in an increased seed germination rate. In summary, these disease protection studies demonstrated an effective control against both bacterial and fungal pathogens in both monocot and dicot crop species, which together with its low production cost, effectiveness at low concentrations, long shelf-life, tolerance to high temperatures, harmlessness to non-target organisms and simple handling and application, make PSP1 a very promising candidate for effective and sustainable disease management in many crop species.