Tobacco bacterial wilt caused by Ralstonia solanacearum is a devastating soil-borne disease, with conventional controls limited by pathogen resistance and environmental pollution. This study investigated the biocontrol potential of Bacillus subtilis strain SNC-183 against tobacco bacterial wilt caused by R. solanacearum. SNC-183, isolated from rhizosphere soil in Luzhou, China, demonstrated 83.33% inhibition efficiency against the pathogen at 56 h fermentation. Field trials revealed that SNC-183 application reduced Ralstonia abundance by 24.66% while enriching beneficial genera like Gemmatimonadaceae and Nitrospira. Soil microbial diversity including ACE and Shannon indices increased significantly, with upregulated functional genes for antibiotic biosynthesis and secondary metabolites. Additionally, treated soils exhibited improved physicochemical properties: alkali-hydrolyzable nitrogen, quick-acting potassium, and elevated pH. These findings highlight SNC-183 as a sustainable alternative for modulating rhizosphere microecology and suppressing tobacco bacterial wilt.

Rice sheath blight (ShB), induced by the necrotrophic fungus Rhizoctonia solani, causes substantial losses in rice (Oryza sativa L.) production, and elucidating the resistance mechanisms is key to controlling pathogen spread. In this study, transcriptomics analysis of rice cultivar Shennong 9816 responding to R. solani AG1-IA infection identified 4542 differentially expressed genes (DEGs; p < 0.05, |log2FC| ≥ 1). Subsequently, gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) analyses of the DEGs revealed significant enrichment in "protein phosphorylation", "plant-pathogen interaction", and "plant-type hypersensitive response". The calcium-binding protein 45 (CML45), calcium-binding protein 36 (CML36), CPK35, wall-associated kinase 2 (WAK2), MSL, Ca2+-binding protein, and WRKY70 genes were upregulated. Overexpression of OsCML45 and OsCML36 was associated with enhanced resistance to R. solani in rice. Moreover, the rice plants overexpressing OsCML45 and OsCML36 showed increased physiological traits. Taken together, these results indicate that OsCML45 and OsCML36 are candidate regulators in rice responses to sheath blight.

Chilli veinal mottle virus (ChiVMV) has been reported to infect Solanaceous crops in recent years, causing severe damage to crop yields. Previous studies have demonstrated that various nutrient elements can improve plant resistance through different strategies. However, there are no reports on the regulation of the resistance to ChiVMV infection by nutrient elements in tobacco. In this study, we found that viral infection decreased calcium (Ca) content in tobacco plants. Interestingly, exogenous application of Ca(NO3)2 improved tobacco resistance to ChiVMV infection. Meanwhile, the key genes and pathways of Ca-induced resistance to ChiVMV infection were verified through transcriptome sequencing analysis. Among them, NtTPS9–2 related to trehalose synthesis and NtEIN3–5 related to ethylene signal transduction were up-regulated in ChiVMV-infected plants and regulated by Ca spraying. Further research demonstrated that silencing the homologous genes of these two genes enhanced the resistance of Nicotiana benthamiana to ChiVMV infection. Our research reveals that Ca element is involved in the regulatory network of viral disease resistance in tobacco, providing a worthy foundation for the cultivation management and molecular design breeding of tobacco plants.

Rhizoctonia solani AG-3 is a major pathogen of solanaceous crops, with subgroups PT, TB, and TM causing potato black scurf and tobacco target spot in China, yet their population structures remain unexplored. Here, we used microsatellite markers to genotype 160 PT isolates from Northeast China, 189 TB and 124 TM isolates from tobacco-growing areas nationwide, and assessed their baseline sensitivity to fludioxonil. The three subgroups exhibited contrasting structures. PT showed high gene diversity (Hexp = 0.634) but significant linkage disequilibrium and low differentiation (FST = 0.008-0.033) without isolation-by-distance, suggesting clonal reproduction and dispersal via contaminated seed tubers. TB displayed moderate diversity (Hexp = 0.385), linkage equilibrium, and significant isolation-by-distance, indicating sexual reproduction with gene flow constrained by geography. The Yunnan population may represent a diversity center. TM showed the lowest gene diversity (mean Hexp = 0.273), low differentiation (FST = 0.005-0.051), and a mixed reproductive mode: Liaoning populations exhibited linkage equilibrium (P > 0.05), while Heilongjiang and Jilin populations showed significant disequilibrium (P < 0.01). High genetic differentiation (FST = 0.269-0.549) confirmed PT, TB, and TM as distinct lineages, with PT and TM most closely related. Fludioxonil effectively inhibited all subgroups (mean EC50 = 0.054-0.090 mg·L-1), with six resistant isolates detected. Sensitivity was independent of origin or genetic background. This study reveals contrasting population structures among AG-3 subgroups, and provides a foundation for subgroup-specific disease management and resistance monitoring.

Tomato yellow leaf curl virus (TYLCV) poses a serious threat to global tomato production. Current management strategies remain limited, highlighting the need for novel antiviral agents. In this study, we evaluated the efficacy of a newly synthesized pyrimidine-guanidine derivative, YYH-6, against TYLCV in tomato (Solanum lycopersicum cv. Micro-Tom) and investigated its underlying mechanisms. Foliar application of YYH-6 significantly reduced viral accumulation and alleviated disease symptoms. Transcriptomic analysis revealed that YYH-6 treatment upregulates defense-related pathways such as plant-pathogen interaction, MAPK signaling, and phenylpropanoid biosynthesis. Results of TRV-based virus-induced gene silencing (VIGS) further indicate that RPP13 and ALS2 function as important resistance genes induced by YYH-6. Activity-based protein profiling, LC-MS/MS, and reverse genetic verification by VIGS indicate that serine hydroxymethyltransferase and STI1 domain-containing proteins are potential target proteins of YYH-6 for TYLCV inhibition. Our findings demonstrate that YYH-6 suppresses TYLCV infection through multitarget modulation of host defense pathways, making it a promising candidate for sustainable management of tomato viral diseases.

Identification of pesticide targets is of great significance for the development of new pesticides. The new compound GLY-15, containing a pyrimidine heterocycle and a moroxydine skeleton structure, has good anti-TMV activity, but the underlying molecular targets and mechanism of action remain elusive. Here, host malate dehydrogenase (MDH), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and tobacco mosaic virus (TMV) coat protein (CP) were identified as potential targets of GLY-15 using activity-based protein profiling (ABPP) and drug affinity responsive target stability (DARTS), and their interactions with GLY-15 were validated by microscale thermophoresis (MST) and pull-down analysis. Functional analyses demonstrate that MDH silencing significantly reduces TMV accumulation, while transient overexpression of MDH results in elevated viral infection. Meanwhile, yeast two-hybrid (Y2H), co-immunoprecipitation (Co-IP), and bimolecular fluorescence complementation (BiFC) analysis uncover that MDH interacts with CP, and their interaction is effectively inhibited by GLY-15. Site-directed mutagenesis identifies E225 as a critical residue for both GLY-15/MDH binding and MDH/CP interaction. Further investigations reveal that GLY-15 functions as an MDH inhibitor and affects its interaction with CP. Meanwhile, we showed that GLY-15 targeting MDH indicates broad antiviral activity against pepper mild mottle virus (PMMoV) and potato virus Y (PVY). This investigation systematically reveals novel insights into the anti-TMV mechanisms of GLY-15, establishing a valuable theoretical basis for antiviral target discovery and plant disease resistance breeding.

Watermelon diseases have become increasingly severe in Liaoning Province, which is a major watermelon-growing region in China. To investigate the occurrence of watermelon virus diseases and identify the predominant virus types, 330 symptomatic samples from three major producing areas in Liaoning Province (Yingkou City, Xinmin City, Chaoyang City) were tested by seven specific primer pairs using reverse transcription-polymerase chain reaction (RT-PCR). The detection results indicated that the incidence of cucumber green mottle mosaic virus (CGMMV) was 54.85% (181/330), followed by watermelon mosaic virus (WMV) with an incidence of 15.76% (52/330). Considering CGMMV’s predominance and the extensive application of grafting in watermelon production, the disease resistance of nine commercially available rootstocks with diverse Cucurbitaceae backgrounds was evaluated. The results showed that all three pumpkin-type rootstocks uniformly exhibited robust resistance to CGMMV, with significantly lower viral accumulation. The bottle gourd rootstock also demonstrated strong resistance to CGMMV. However, wild watermelon rootstocks, due to intraspecific variation and genetic diversity within their germplasm, display a bimodal distribution of high resistance and high susceptibility. These results confirm that CGMMV is the primary watermelon virus in Liaoning Province and highlight the use of pumpkin-type rootstocks as an effective grafting strategy to enhance CGMMV resistance.

Tomato mottle mosaic virus (ToMMV) is a major threat to cultivating tomatoes and other solanaceous plants. Here, an infectious clone of the ToMMV Huludao isolate was constructed, and ToMMV infection significantly reduces soluble sugar, soluble phenolic, and vitamin C contents, while increases titratable acid content in Micro-Tom fruits, thus altering their flavor profile and quality. Integrated transcriptomic and metabolomic analysis indicate that ToMMV infection induced 2090 differentially expressed genes and 709 differentially accumulated metabolites in Micro-Tom fruits. Then, functional analysis using gene silencing validated that bifunctional 3-dehydroquinate dehydratase/shikimate dehydrogenase and glyceraldehyde-3-phosphate dehydrogenase induced by ToMMV in the amino acid biosynthesis pathway play critical roles in tomato fruit quality, while 4-coumarate-CoA ligase, phenylalanine ammonia-lyase and scopoletin glucosyltransferase in the phenylpropanoid biosynthesis pathway were required for host resistance. Our findings elucidate molecular mechanisms of ToMMV-induced fruit quality alteration and highlight metabolic targets for enhanced viral resistance in tomatoes.

Rhizoctonia solani AG3-TB is a destructive necrotrophic pathogen causing tobacco target spot disease. WRKY70 acts as a key regulator integrating salicylic acid (SA) and jasmonic acid (JA) signals in plant immunity. Our previous study found that NtWRKY70 in Nicotiana tabacum L. is significantly induced by R. solani AG3-TB infection; however, its functional mechanism remains elusive. In this study, bioinformatics analysis showed that NtWRKY70 is a nuclear localized protein with conserved domains and transcriptional autoactivation activity. Further investigations using virus-induced gene silencing (VIGS), CRISPR/Cas9-mediated knockout and overexpression transgenic plants confirmed that NtWRKY70 acts as a positive regulator against R. solani AG3-TB. Based on RNA-seq data and differential expression genes (DEGs) screening, the total of 11 defense-related genes were significantly upregulated. Exogenous application of SA and methyl jasmonate (MeJA) induced NtWRKY70 expression and decreased the lesion diameter, which indicated that NtWRKY70 is potentially linked to the activation of downstream SA and JA signaling pathways. Collectively, our findings suggest that NtWRKY70 participates in tobacco defense against R. solani AG3-TB, potentially by coordinating SA and JA signaling to activate defense-related genes, which provides a valuable candidate for tobacco disease-resistant breeding.

Nanocarrier-mediated delivery of double-stranded RNA (dsRNA) is a promising strategy for plant disease control. Our previous study has shown that the self-assembled ε-poly-l-lysine/carboxymethyl chitosan (ε-PL@CMCS) nanocarrier significantly improves the efficiency of RNA interference (RNAi) against Rhizoctonia solani AG3 TB. However, the molecular mechanisms underlying this enhancement and the potential ecological impacts on phyllosphere microbial communities remain unclear. In this study, we confirmed that dsRsGH1@ε-PL@CMCS had no adverse effects on the growth and development of plants. Transcriptome analysis revealed that DEGs were significantly enriched in ‘SNARE interactions in vesicular transport’ pathway. Among them, dsRsGH1@ε-PL@CMCS specifically upregulate the vesicle transport protein SEC22 in Nicotiana tabacum. Surface plasmon resonance (SPR) assay demonstrated that the dsRsGH1@ε-PL@CMCS binds to SEC22 protein with 7.6-fold higher affinity than that of the naked dsRsGH1. Silencing SEC22 in the dsRsGH1@ε-PL@CMCS treatment reduced the silencing efficiency of RsGH1 from 53.3% to 39%, confirming its essential role. Concurrently, high-throughput sequencing revealed that SIGS treatments did not disrupt bacterial community structure but increased fungal diversity and suppressed the pathogen, while enriching beneficial fungi such as Tulasnella. Our findings elucidate a molecular link between nano-bioprotectant dsRsGH1@ε-PL@CMCS-enhanced RNAi and host vesicle transport, while confirming the biocompatible and microbiome-modulating potential. This provides a dual perspective for developing efficient and sustainable RNAi-based strategies for protecting plants.

This study analyzed the transcriptome, proteome and ubiquitylome of ToBRFV-infected tomato plants and verified the antiviral roles of SlCHS, SlPAO, and SlCCoAOMT in tomato plants through TRV-VIGS assays. Tomato brown rugose fruit virus (ToBRFV) infection causes leaf mottling and fruit wrinkling, significantly affecting tomato quality. Understanding the mechanisms of tomato plants in combating ToBRFV infection is fundamental to the development of effective strategies for viral disease control and management. To investigate the effects of ToBRFV infection on the gene regulatory network of tomato plants, we performed transcriptome, proteome and ubiquitylome sequencing on ToBRFV-infected tomato plants. A total of 874 differentially expressed genes (DEGs) and 675 differentially expressed proteins (DEPs) were identified. Most of them were involved in hormone signal transduction, MAPK signaling pathway, flavonoid biosynthesis, arginine and proline metabolism, and phenylalanine metabolism, and some of these proteins were modified by ubiquitination. Furthermore, virus-induced gene silencing (VIGS) assays revealed that silencing SlCCoAOMT or SlCHS, two flavonoid biosynthesis-related genes, enhanced tomato resistance to ToBRFV infection, while silencing SlPAO, an arginine and proline metabolism-related gene, promoted ToBRFV infection. These results reveal the key regulatory networks of tomato in response to ToBRFV infection, and identify SlCCoAOMT, SlCHS and SlPAO as potential candidate genes for disease-resistant breeding.

Tomato leaf curl New Delhi virus (ToLCNDV) is a bipartite begomovirus (family Geminiviridae) originally isolated from tomatoes and later evolved to cross-infect cucurbit crops, causing severe economic damage in Asia and Europe. In this study, we sequenced and characterized complete genomes of two ToLCNDV isolates collected from Hebei (ToLCNDV-HB) and Jiangsu (ToLCNDV-JS) provinces of China infecting melon. We constructed infectious clones for ToLCNDV-HB and ToLCNDV-JS, which could systemically infect Nicotiana benthamiana, tomato, and four species of cucurbitaceous plants. Notably, ToLCNDV-HB induced more severe symptoms and accumulated higher viral DNA and protein accumulation than ToLCNDV-JS in N. benthamiana, melon, and bottle gourd. Sequence analysis showed that sequence variations are present only in AV2, AC1, and AC4. However, only the AV2 ORF from ToLCNDV-HB was more efficient than that from that ToLCNDV-JS in enhancing potato X virus’s pathogenicity and suppressing post-transcriptional gene silencing (PTGS). An AV2-swapping experiment between ToLCNDV-HB and ToLCNDV-JS confirmed its vital role in determining the differential pathogenicity. Further evidence shows that virions from both clones are mechanically transmissible. This is the first report comparing the differential pathogenicity of two Chinese ToLCNDV isolates in cucurbits. The AV2 protein, a key pathogenicity determinant, represents a potential target for breeding ToLCNDV-resistant cucurbit varieties.

Tobacco root rot caused by Fusarium spp. infection results in significant losses to tobacco production. The disease is primarily prevalent in southern and central China, particularly in Fujian, Shandong, and Shanxi (Qiu et al. 2018). In July 2023, tobacco samples (n=10) exhibiting root rot symptoms were collected from Maodianzi Town (40.67°N, 124.62°E; cv. Liaoyan 21) and Qingyishan Town (40.68°N, 124.62°E; cv. Liaoyan 21) in Kuandian, Liaoning Province, China. The disease incidence in the surveyed fields reached approximately 60% to 70% based on the five-point sampling method. The symptoms exhibited blackening and rotting of the main root, stem base, and sparse fibrous roots. To isolate and identify the pathogen, the diseased tissues (2 × 2 mm) were cut from the edge of root lesions, treated with 75% alcohol rinsed with sterile water, and then incubated on potato dextrose agar (PDA) medium at 28 ℃. A total of 21 isolations were obtained through the single-spore isolation method. The experiment was conducted in a laminar flow cabinet and replicated three times. Two morphological types were observed among the colonies and spores of these strains. One type exhibited white, fluffy colonies. Large conidia were sickle-shaped, slightly rounded at both ends, and mostly had two to five septa (16.2×2.1 μm). Small conidia were spindle-shaped to ovate (8.2×2.3 μm) and generally had one septum (Qiu et al. 2024). Another type showed colonies with pink and slightly purple hues, and the spores were sickle-shaped, slightly curved spores with pointed somewhat ends, small conidia were mostly without septa or one septum (15.1×2.0 μm), and large conidia were unequally septate or sickle-shaped (39.4×4.2 μm), mostly with three to five septa (Sang et al. 1998). The mycelia of both fungal isolates had a small number of branches. Two isolates (GF11, GF12) were selected from two different morphologies, and subjected to DNA extraction using the CTAB method (Sagar et al. 2014). Sequencing analysis of the two strains was performed using the nuclear ribosomal internal transcribed spacer region (ITS, GenBank accession no. PQ608542 and PQ608543), translation elongation factor (TEF-1a, PQ671287 and PQ671288), and the second largest subunit of RNA polymerase II (RPB2, PQ671289 and PQ671290) (O'Donnell et al. 2000, 2015). Upon comparison with NCBI database sequences, the ITS and EF-1α sequences of strain GF11 were found to exhibit a maximum homology of 100% with the corresponding sequences of F. oxysporum, while the RPB2 sequence showed a maximum homology of 99.66%. For strain GF12, its ITS, EF-1α, and RPB2 sequences were determined to have maximum homologies of 100%, 99.72%, and 99.55% respectively with the corresponding sequences of F. solani. According to Koch's postulates, GF11 and GF12 were used for pathogenicity testing. Nicotiana tabacum cv. K326 were cultivated at the 26°C growth chamber and used at the four-leaf stage. The base of the stem of ten plants was wrapped in sterile cotton treated with a spore suspension (1×106 conidia/mL) of GF11 and GF12. The control group was treated with sterile water. After 10 days, the GF11 and GF12 treated groups showed symptoms consistent with those observed in the field, with the fibrous roots becoming sparse and the leaves turning yellow, and the F. oxysporum and F. solani were successfully re-isolated and identified by sequencing. This is the first report of tobacco root rot caused by Fusarium spp. in northeast China.

Rhizoctonia solani Kühn is an important fungal pathogen that causes serious crop yield losses worldwide. The application of nanoscale strategies based on RNA interference (RNAi) represents an environmentally friendly and efficient approach for plant disease control. In this study, R. solani glycosyl hydrolase family 1 (RsGH1), which functions as a cell wall degrading enzyme (CWDE), and was screened as a prospective RNAi target gene for managing R. solani AG3 TB. Additionally, a novel nanosystem for loading and stabilization of double-stranded RNA (dsRNA) was developed. When the mass ratio of ε-poly-L-lysine (ε-PL) to carboxymethyl chitosan (CMCS) is 1:1, ε-PL can spontaneously conjugate with CMCS to form nanoscale spherical particles by electrostatic interaction, hydrogen bonding and Van der Waals forces. Compared with ε-PL alone, the introduction of CMCS resulted in more regular and uniform nanoparticles. dsRsGH1 spontaneously binds with ε-PL@CMCS, which is referred to as dsRsGH1@ε-PL@CMCS. ε-PL@CMCS protected dsRNA from RNase A degradation effectively. The combination of dsRsGH1 with ε-PL@CMCS remarkably improved the deposition and adhesion of dsRsGH1 droplets on Nicotiana tabacum (N. tabacum) leaves. The application of ε-PL@CMCS improved the RNAi efficiency of dsRsGH1 and prolonged its protective duration on crops. dsRsGH1 derived from R. solani AG3 TB also exhibited broad-spectrum activity against R. solani AG1-IA in rice and maize plants. In this study, a self-assembled multi-component nano-fungicide was designed based on dsRNA and nanocarriers. This work proposes an eco-friendly strategy to manage R. solani.

Tobacco wildfire disease, caused by Pseudomonas syringae pv. tabaci, severely reduces tobacco yield and quality, yet the host response remains poorly understood. Here, a comprehensive transcriptomic analysis of Nicotiana tabacum infected with P. syringae pv. tabaci YH3 was performed at four developmental stages. Among the top 12 KEGG pathway enrichment analysis, the differentially expressed genes (DEGs) involved in the MAPK signaling pathway-plant, carbon fixation in photosynthetic organisms, plant hormone signal transduction, ribosome, plant-pathogen interaction, and RNA degradation were significantly enriched at three time points. Notably, among the identified DEGs, leucine-rich repeat receptor-like protein kinase (LRR-RLK), indole-3-acetic acid (IAA), and cysteine synthase (CS) emerged as potential key regulatory genes involved in the tobacco response to P. syringae pv. tabaci YH3 infection. These findings provide a molecular framework for understanding the transcriptomic response of N. tabacum to P. syringae pv. tabaci infection and offer promising candidate genes for investigations into the interaction mechanisms between this pathogen and its host plants.

Potato black scurf and tobacco target spot are significant agricultural diseases primarily caused by Rhizoctonia solani AG-3, which is further classified into potato type (PT), tomato type (TM), and tobacco type (TB) subgroups, with the naming of these subgroups originally indicating their respective infection hosts potato, tomato, and tobacco. This study determined the subgroup classification of 129 R. solani AG-3 isolates recovered from tobacco leaves exhibiting target spot disease in major tobacco-cultivating regions of China, as well as 80 R. solani AG-3 isolates obtained from potato stem cankers and tuber sclerotia in Liaoning, Jilin, and Heilongjiang provinces, and Inner Mongolia autonomous region of China. Sequence analysis of the internal transcribed spacer (ITS) regions revealed that all potato isolates belonged to the R. solani AG-3 PT subgroup, whereas the tobacco isolates were classified into TM and TB subgroups. Specifically, 51 strains from the northeast (Liaoning, Jilin, and Heilongjiang provinces) belonged to the TM subgroup, whereas the others belonged to the TB subgroup. Phylogenetic analysis indicated a closer relationship between AG-3 TM and AG-3 PT compared with AG-3 TB. Population genetic analysis highlighted distinct genetic variations among the subgroups, with the AG-3 TB subgroup isolates exhibiting fewer ITS1 variable sites and the AG-3 PT subgroup displaying a higher number of ITS2 variable sites. Furthermore, comparisons were made regarding macroscopic vegetative interactions, biological characteristics, pathogenicity to potato and tobacco, and susceptibility to thifluzamide among the three subgroups. The results indicated no macroscopic somatic interactions among the subgroups, with the highest frequency of somatic incompatibility observed within AG-3 PT, followed by AG-3 TM and AG-3 TB. Additionally, the three subgroups differed in colony color, sclerotium morphology, production time, and distribution location on potato dextrose agar medium, with AG-3 TM being the least likely to produce sclerotia. Regarding temperature, optimal growth conditions varied among the subgroups. Regarding pathogenicity, the AG-3 PT subgroup strains were more pathogenic on tobacco and potato stem bases compared with the AG-3 TB subgroup, whereas the AG-3 TB and TM subgroup strains were more pathogenic on leaves. Notably, AG-3 TM exhibited remarkable virulence toward both the stem base and leaves. The AG-3 PT subgroup strains exhibited the highest susceptibility to thifluzamide, with a susceptibility baseline of 0.037 +/- 0.013 mgliter-1, followed by the AG-3 TM subgroup strains with a baseline of 0.111 +/- 0.034 mgliter-1 and the AG-3 TB subgroup strains with a baseline of 0.137 +/- 0.035 mgliter-1. This study contributes to a deeper understanding of the biology and etiology of the three subgroups of R. solani AG-3, providing a valuable theoretical basis for the scientific control and management of tobacco target spot and potato black scurf diseases in China.

The necrotrophic fungal pathogen Rhizoctonia solani anastomosis group 3 (AG3-TB) is a major cause of global tobacco crop yield losses. Secreted proteins produced by filamentous fungi, as important virulence factors, play a core role in the interaction between plants and pathogens. In this study, we identified a secretory protein, RsDN3377, which localised to the intercellular space and induced cell death in Nicotiana benthamiana. Heterologous expression in Escherichia coli coupled with matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry analysis confirmed RsDN3377 possessed deacetylase activity. In addition, RsDN3377 was an essential pathogenicity factor for mycelial development by double-stranded RNA-mediated gene silencing. Through yeast two-hybrid and bimolecular fluorescence complementation assays, we demonstrated that RsDN3377 interacted with the calcium-binding protein NtCML19. In addition, transgenic Yunyan 87 overexpressing NtCML19 exhibited enhanced resistance to R. solani AG3-TB infection. Microscale thermophoresis analysis verified the calcium-binding activity of NtCML19. These lines of evidence indicate that the deacetylase RsDN3377 is secreted by R. solani AG3-TB, and this protein, critical for promoting fungal mycelial development and pathogenicity, was disrupted by its resistance-related interaction with NtCML19.

BACKGROUNDBotrytis cinerea is one of the most serious plant diseases and severely threatens agricultural production. The rapidly intensifying resistance makes most commercial chemical fungicides lose control efficacy. Developing new fungicides with novel structures and modes of action is an effective measure to solve this problem.RESULTSIn this work, 29 novel sulfonamide compounds containing pinacolone scaffolds were designed and synthesized based on the active substructure splicing strategy. The biological activity assay on three kinds of Botrytis cinerea strains manifested that these compounds exhibit moderate to excellent antifungal activity. Compounds 3a-1 and 3a-11 displayed the highest in vitro antifungal activity similar to control agents carbendazim, procymidone, and boscalid. Compound 3c had the lowest EC50 value of 1.96 mu g/mL against strain PJ-02 compared to boscalid (6.90 mu g/mL). Bioassay results on strawberry fruits and tomato pots indicated that compounds 3a-1 and 3a-11 also possess superb in vivo antifungal activity compared to control agents. The electronic conductivity measurement results showed that compound 3a-1 can significantly increase the membrane permeability of Botrytis cinerea mycelium. Scanning electron microscopy observation revealed that compound 3a-1 could cause the Botrytis cinerea mycelium to twist and break, and inhibit mycelium branching. Density functional theory calculation and molecular electrostatic potential distribution were also used to analyze the activity mechanism of target compounds.CONCLUSIONDue to their excellent antifungal activity against Botrytis cinerea, these novel sulfonamide derivatives containing pinacolone scaffolds could be considered qualified fungicide candidates. Preliminary exploration of the mechanism suggests that this kind of compound may possess a novel mode of action. (c) 2025 Society of Chemical Industry.

Cytidine peptide compounds have emerged as promising candidates for antiviral agents, but their large-scale production and mode of action remain underexplored. By optimizing temperature control and stirring efficiency, and replacing trifluoroacetic acid with an HCl/dioxane system for tert-butyloxycarbonyl (Boc) deprotection, efficient preparation of SN15 was achieved with a 78.47 % yield without the need for column chromatographic purification. Antiviral assays showed that SN15 inhibited TMV accumulation in single cells by 53.44 % at 250 μg/mL and significantly suppressed systemic infections by PVY, PMMoV, and TuMV, reducing viral RNA accumulation by 54.16 %, 41.14 %, and 61.85 %, respectively. Transcriptomic analysis identified 9676 differentially expressed genes (DEGs), with ribosomal protein-related pathways significantly upregulated and hormone signaling/ubiquitination pathways downregulated. Proteomic analysis revealed 216 differentially expressed proteins (DEPs), including ribosomal components and stress-response proteins, consistent with transcriptomic trends. Results of TRV-VIGS showed that silencing of 60S ribosomal protein L6 or lipid transfer-like protein VAS significantly increased TMV accumulation, confirming its critical role in antiviral defense, while silencing of peroxidase N1 precursor and E3 ubiquitin-protein ligase CIP8-like isoform X1 inhibited viral replication. This study reveals the molecular mechanism by which SN15 exerts antiviral effects through multi-pathway synergistic regulation, and provides a theoretical basis for the industrial production and broad-spectrum antiviral application of the fluorinated cytidine peptide compound SN15.

BACKGROUND:Our laboratory participated in the development of a 10.5 billion colony-forming units (CFU) g-1 Paenibacillus polymyxa and Bacillus subtilis wettable powder (PBM), which has been registered in China as a novel microbial fungicide. Subsequent research has demonstrated that PBM exhibits significant inhibitory effects on tobacco target spot disease caused by Rhizoctonia solani, yet the underlying mechanisms remain unclear. RESULTS:PBM effectively inhibits the mycelial growth of R. solani and induces morphological distortions in the fungal hyphae. Field trials demonstrated that PBM provid a control efficiency of 86.03 ± 1.76% against R. solani. Additionally, PBM enhanced agronomic traits of the plants, including height, leaf length and leaf width. Analysis of the phyllosphere microbial community revealed that application of PBM to the abaxial surface of leaves under high humidity conditions at 28 °C facilitates the colonization of biocontrol bacteria. Moreover, PBM not only significantly reducedthe abundance of pathogenic microorganisms including R. solani, but also promote the enrichment of beneficial microbial communities on the leaf surface, thereby restoring the microbial community structure to a state resembling that of healthy plants. Furthermore, PBM treatment stimulated host resistance responses by inducing the expression of defense-related genes and upregulating the activity of defense-related enzymes. CONCLUSION:This study elucidates the functions and mechanisms of the composite microbial pesticide PBM, underscoring its potential as an environmentally friendly biological control agent against plant diseases caused by R. solani. © 2025 Society of Chemical Industry.