Camphora officinarum Nees (camphor tree) is an economically and ornamentally important native tree species in China. In recent years, a destructive wilt disease characterized by leaf desiccation, xylem discoloration and tree death has threatened the camphor populations, especially ancient camphor resources, in several southern provinces, yet its causal agents remain unclear. In this study, the samples of diseased plants from Anhui, Jiangxi, Hunan and Guangxi province were collected and 46 fungal isolates belonging to four morphological types were obtained. Pathogenicity tests confirmed that 12 representatives of dominate type (29 isolates) colonized vascular tissues of camphor seedlings and reproduced field disease symptoms. Based on the formation of long-necked globose perithecia and helmet-shaped ascospores among 19 isolates, the pathogens were identified as members of genus Ceratocystis. The mating-type and phylogenetic analysis determined that 29 isolates were self-sterility or self-fertility Ceratocystis fimbriata, Ce. manginecans and Ce. eucalypticola. Cross-pathogenicity tests further confirmed their potential to infect other Cinnamomum spp. In addition, owing to the conserved 198E residue in β-tubulin, three species of Cerarocystis were sensitive to benomyl. These results provide the first comprehensive characterization of the pathogens causing Ceratocystis wilt of camphor trees in southern China, revealing diversity in species, morphology, mating types, hosts and virulence. The benomyl sensitivity of Ceratocystis spp.,offers an effective strategy for disease management. © 2026 Society of Chemical Industry.

Ceratocystis fimbriata, the causal agent of black rot in sweetpotato, compromises the phytosanitary integrity of vegetative propagation and persists through poorly understood inoculum sources. Although crop rotation is widely used to reduce pathogen pressure, the ability of alternative hosts and reservoirs to sustain inoculum has not been clearly defined. This study investigated (i) the susceptibility of commonly rotated crop species to C. fimbriata using no-wounding, wounding, and seedling inoculation assays and (ii) the extent to which inoculum from infested soil or inoculated roots independently initiates infection in sweetpotato slips. Our study revealed significant crop × time interactions across all host assays (P < 0.001). Under no-wounding conditions, squash and watermelon supported high infection incidence, serving as asymptomatic reservoirs. Conversely, wounding and seedling assays increased disease development and mortality in the most susceptible hosts (sweetpotato and morning glory), whereas most rotation crops showed low or no mortality. Survival analysis identified sweetpotato as the most vulnerable host (log-rank test, P < 0.001), whereas most alternative hosts exhibited a significantly reduced hazard relative to sweetpotato (hazard ratio < 1; P < 0.05). In the slip experiment, inoculum from both infested soil and infected roots independently caused infection. Pathogen detection via qPCR confirmed colonization up to 76 mm from the stem base, with the T3G9 marker exhibiting significantly higher sensitivity than T5G26 (P = 0.0079). Together, these findings identify alternative hosts, infested soil, and infected roots as independent inoculum reservoirs that drive black rot epidemiology and threaten the sustainability of sweetpotato propagation systems.

The spoVF operon, encoding the dipicolinic acid (DPA) synthase, is critical for sporulation in Bacillus subtilis. A recent study suggested that spoVF expression in vegetative cells promotes biofilm formation, yet the detailed regulatory pathways and the underlying metabolic connections remain to be fully elucidated. In this study, deletion of spoVF subunits spoVFA and spoVFB severely reduced DPA synthesis, downregulated mreB gene expression, and impaired biofilm formation, with mutant ΔA showing stronger effects than mutant ΔB. Although wild type B. subtilis 168 cells exhibited rod shape, double mutant ΔAΔB cells were spherical. In the MT strain, engineered for enhanced spoVF expression during vegetative growth, the upregulation of key TCA cycle genes (e.g., citC) and glutamate synthesis genes (e.g., gltA) was observed. This metabolic reprogramming was accompanied by the promotion of Spo0A phosphorylation. The activated Spo0A~P then inhibited the SinR and AbrB repressors, which led to the activation of the eps and tasA biofilm operons. The MT strain showed superior stress tolerance to high temperature (42 °C), salt, acidic and alkaline pH, and UV-A and UV-B radiation. Additionally, the MT strain exhibited higher nutrient competition ability, and in vitro and in vivo antifungal activities against the sweet potato (Ipomoea batatas L. Lam) storage root pathogen Ceratocystis fimbriata compared to mutant ΔA, ΔB, and ΔAΔB strains. This study elucidates how the spoVF operon links the central metabolic pathways with B. subtilis cell morphology and biofilm formation, offering a novel target for engineering advanced Bacillus-based biocontrol agents. © 2026 Society of Chemical Industry.

The Characterization and Antifungal Efficacy of NJ-62 Protein from Weizmannia coagulans CGMCC 9951 against Ceratocystis fimbriata.

Insect vectors are increasingly recognized as overlooked drivers of postharvest disease spread. Ceratocystis fimbriata, the causal agent of sweetpotato black rot, can spread rapidly in postharvest environments. Previous work established that Drosophila hydei can acquire viable C. fimbriata propagules both externally and internally, identifying this fly as a potential vector in storage facilities. Here, we expand on that finding by testing whether vector density influences disease transmission and by developing molecular diagnostic assays to improve pathogen detection. Transmission assays were conducted with four fly densities (10, 30, 50, and 80 flies) exposed to inoculum sources and then transferred to clean targets (sterile agar and uninfected sweetpotatoes, with and without wounds). Transmission occurred regardless of fly density, indicating that even small populations are sufficient to spread the inoculum, although incidence was significantly higher in wounded roots. To complement these assays, we standardized qPCR assays using dual-quencher probes targeting two C. fimbriata-specific markers (T3G9 and T5G26). Pathogen DNA was detected in both flies and asymptomatic roots, with the more sensitive marker identifying latent infections that were not visible through symptoms. Together, these results demonstrate that D. hydei vectors C. fimbriata in a density-independent manner, that wounding increases the success of infection, and that qPCR diagnostics can detect transmission events that are overlooked by visual assessment. These findings provide new epidemiological insight into postharvest black rot and support integrated management strategies that combine vector suppression with molecular surveillance.

Biocontrol potential of Bacillus velezensis ATC-AL against Ceratocystis fimbriata and its application in sweetpotato postharvest preservation

Sweetpotato black rot, caused by the fungus Ceratocystis fimbriata, adversely affects yield and postharvest quality. We applied integrated transcriptomic and metabolomic profiling to elucidate resistance mechanisms in the black rot–resistant cultivar SS23 versus the susceptible cultivar GS08. Phenotypically, SS23 developed substantially milder symptoms and smaller lesions, whereas GS08 suffered extensive root damage. Multi-omics integration revealed that SS23 mounted a rapid defense response characterized by the upregulation of defense-related genes (e.g., peroxidase, chitinase) and a coordinated metabolic reprogramming that increased levels of resistance-associated compounds, including the amino acids leucine and proline and sesquiterpenoids such as plumericin. By contrast, GS08 exhibited a delayed transcriptional response and suppression of amino acid metabolic pathways. Our analyses highlight the central role of terpenoid biosynthesis in resistance: SS23 activated terpene synthases (IbTPS) together with cytochrome P450s to promote production of antifungal terpenoids, whereas GS08 primarily upregulated the upstream mevalonate pathway enzyme HMG-CoA reductase (IbHMGR) without corresponding downstream specialization. Volatile profiling detected 13 terpenoids in SS23 following infection (including isoterpinolene) versus 6 in GS08. To the best of our knowledge, we are the first to report the identification of specific antifungal terpenoids, such as isoterpinolene, being induced in sweetpotato roots in response to black rot. Tightly interconnected gene–metabolite networks in SS23 appear to constrain pathogen progression, whereas metabolic dysregulation in GS08 strongly correlated with susceptibility. These findings emphasize terpenoid-pathway manipulation as a promising strategy for developing black rot–resistant sweetpotato and nominate several core genes as candidate molecular markers for precision breeding.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12870-025-07862-3.

The GATA transcription factors regulate plant growth, development, and stress responses, but our knowledge of their functions in sweetpotato and related Ipomoea species remains limited. Through analytical methods of bioinformatics, this study identified 410 GATA genes across seven sequenced Ipomoea species: sweetpotato (158), I. trifida (54), I. triloba (62), I. nil (39), I. purpurea (32), I. cairica (32), and I. aquatica (33). Phylogenetic analysis revealed that these GATA genes clustered into four distinct subfamilies (I-IV). Chromosomal mapping showed an uneven distribution pattern, with complete absence of GATA genes on certain chromosomes in each species. Duplication analysis indicated differential expansion mechanisms: tandem duplications primarily drove GATA gene expansion in I. triloba, I. trifida, and I. nil, whereas segmental duplications were predominant in sweetpotato and I. cairica. Promoter analysis identified multiple stress-responsive cis-regulatory elements, including ABRE, ARE, CGTCA-motif, GC-motif, LTR, MBS, TCA-element, TC-rich repeats, and TGACG-motif. Expression profiling under various stresses (salt, drought, Ceratocystis fimbriata and Ditylenchus destructor) detected 29–60 differentially expressed GATA genes (DEGs). Three representative DEGs (IbGATA33, IbGATA38, and IbGATA126) were validated by qRT-PCR, with results corroborating the transcriptome data. This study may contribute to further understanding of the evolution and function of GATA genes among the Ipomoea species, including sweetpotato.

Postharvest biocontrol ability and antagonistic mechanism of Streptomyces djakartensis MEPS155 against Ceratocystis fimbriata in sweetpotato

Drosophila hydei (Diptera: Drosophilidae) is an emerging pest within sweetpotato storage facilities in North Carolina because of their ability to mechanically transmit Ceratocystis fimbriata, a fungal pathogen of sweetpotato roots. Information about D. hydei population dynamics in sweetpotato storage facilities is limited. To address this knowledge gap, this study conducted laboratory and field behavioral choice experiments to assess the most attractive bait for pest monitoring. Laboratory reared flies were placed in arenas containing 2 liter plastic bottle traps each baited with a single treatment: (i) banana and yeast mixture, (ii) fermented sugar water with yeast, (iii) apple cider vinegar, and (iv) water control. Flies captured in each bait treatment were counted after 24 h. The most effective bait was the banana yeast mixture. Field bait assays included the same baits distributed across 20 10 × 15 m storage rooms at two different times spaced 7 d apart (N = 40 replications per treatment). Sticky cards were placed in each room to estimate Drosophila spp. abundance and total arthropod diversity. Field bait experiments showed that apple cider vinegar was a preferred bait for D. hydei and D. funebris, which were the two most common species in sweetpotato storage facilities. In contrast to a previous study of Drosophila spp. in sweetpotato storage, our study found that D. funebris was the most common species. Further research will be necessary to assess D. funebris and its impact on sweetpotatoes. Determining the optimal bait will enable synthesis of chemical baits for population monitoring in sweetpotato storage facilities.

Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins play evolutionarily conserved roles in intracellular vesicle trafficking and membrane fusion across eukaryotes. In pathogenic fungi, various SNARE homologs have been shown to critically regulate host infection processes. Here, we characterize the functional roles of CfSec22 in the sweet potato black rot pathogen Ceratocystis fimbriata. Phylogenetic and domain analyses demonstrate that CfSec22 shares homology with Sec22 proteins from Saccharomyces cerevisiae (ScSec22), Magnaporthe oryzae (MoSec22), and other fungi, containing both the characteristic Longin homology domain and V-SNARE domain. Functional studies reveal that CfSec22 regulates growth, conidiation, and virulence of C. fimbriata. Deletion of CfSEC22 resulted in abnormal vacuole morphology and impaired endocytosis. The ΔCfsec22 mutant displayed heightened sensitivity to diverse stress conditions: oxidative, endoplasmic reticulum, and cell wall stressors. Subcellular localization studies confirmed the endoplasmic reticulum residence of CfSec22. Finally, we established that CfSec22 regulates the secretion of virulence-associated proteins and is required for the induction of ipomeamarone in infected sweet potato tissues. Together, our findings demonstrate that CfSec22-mediated vesicle trafficking serves as a critical regulatory mechanism supporting growth, conidiogenesis, and pathogenicity in C. fimbriata.

BackgroundSweet potato (Ipomoea batatas) production is threatened by fungal diseases like Fusarium wilt and black rot, causing yield losses. Remedies like fungicides pose environmental and health risks, prompting the need for sustainable biocontrol solutions.ResultsIn this study, an endophytic bacterium strain CMML21-49 isolated from sweet potato roots in Naju-si, Korea exhibited strong in vitro antifungal activity against Fusarium oxysporum, Ceratocystis fimbriata, Sclerotinia sclerotiorum, and Rhizoctonia solani. Based on 16S rRNA and gyrB gene sequencing, the strain CMML21-49 was identified as Bacillus velezensis. Lipopeptides (bacillomycin D, fengycin A, surfactin A) were identified by UPLC-QTOF-MS and these crude lipopeptides drove the antifungal effects, achieving strong inhibition of F. oxysporum and C. fimbriata. Optimized culture conditions yielded 0.93 g/L lipopeptides, scaled to 0.96 g/L in a 1.5 kL fermenter, and a spray-dried formulation maintained high viability (6.4–8.9 × 1010 CFU/g) over six weeks at 4–54℃. Application of CMML21-49 reduced F. oxysporum and C. fimbriata diseased areas in storage root assays and showed 61.54% and 53.85% control efficiencies against Fusarium wilt and black rot, respectively, in field trials. Additionally, postharvest assays achieved over 50% disease reduction by treatment of the strain.ConclusionThis study presents optimized large scale culture conditions for the B. velezensis strain as well as excellent storage stability and suitability for long-term transport and on-farm use. The findings highlight the B. velezensis strain as a promising and sustainable biocontrol agent, offering a scalable, eco-friendly biocontrol solution for sweet potato fungal diseases.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12866-025-04334-4.

Sweetpotato, a vital global crop, cash, and fodder crop, faces significant threats from black rot disease caused by Ceratocystis fimbriata (C. fimbriata). Benzyl isothiocyanate (BITC) is a biologically active essential oil derived from cruciferous plants, widely used for food preservation and exhibiting antimicrobial and antitumor properties. In this study, BITC significantly inhibited C. fimbriata growth and induced cellular damage. Furthermore, through proteomics and bioinformatics analyses, mitochondrial peroxiredoxin PRX1 (PRX1) was identified as a potential target protein of BITC in C. fimbriata, confirming its role in regulating the response of BITC-treated C. fimbriata to oxidative damage. Finally, sweetpotato storage simulation experiments demonstrated that BITC effectively prevents and controls the growth of C. fimbriata during sweetpotato storage. These results provide the basis for using BITC to control sweetpotato black rot, offering insights into developing highly selective and low-negative-impact antisweetpotato black rot disease compounds, and presenting a new strategy for controlling C. fimbriata contamination in sweetpotatoes.

North Carolina is the top producer of sweetpotatoes in the United States and accounts for more than 50% of the nation's yearly production. The presence of fungal pathogens such as Ceratocystis fimbriata, the causal agent of black rot, remains a major concern for sweetpotato producers and is commonly managed through the application of fungicides. As a result of the European Union's (EU) restricted residue tolerances for import products treated with pesticides, the use of fungicides for management of sweetpotato diseases is limited. Identifying fungicides and application practices that ensure disease-free sweetpotatoes while meeting export residue requirements is critical for effective disease management and export marketability. Field experiments were executed in 2022 and 2023 to quantify residue values of three active ingredients (thiabendazole, azoxystrobin, and difenoconazole) when applied at either bedding, transplant, or both bedding and transplant when managing sweetpotato black rot. Root and vine samples were collected at harvest to analyze the detectable residue levels of the applied active ingredients at different stages of sweetpotato production. High-performance liquid chromatography analyses revealed that the average detected residues for all the tested active ingredients and application timings fell under the maximum residue level thresholds for the United States, Canada, and the EU but not the United Kingdom. In the field experiments, fungicide treatments were not significantly different from nontreated plots for plot vigor, percentage disease incidence, or yield. Although the residues from the three tested products in this study were not a concern for U.S., EU, and Canadian markets when applied during sweetpotato field production, further research is needed to determine their potential as an effective management tool for sweetpotato black rot.

Antifungal activity of volatile organic compounds produced by Weizmannia coagulans CGMCC 9951 on Ceratocystis fimbriata in postharvest sweet potatoes and its potential biocontrol.

Ceratocystis fimbriata is a destructive fungal pathogen that infects various economic crops. Nevertheless, the infection mechanism of this fungus is still unclear. Our previous studies have shown that the transcription factor CfSwi6 downstream of the cell wall integrity pathway is involved in regulating the pathogenicity of C. fimbriata. To further clarify the pathogenic mechanism of this pathway, upstream MAPKs (CfBck1-CfMkk1-CfSlt2) were characterised in this study. Deletion of CWI-MAPK genes resulted in an almost complete loss of pathogenicity of C. fimbriata. Importantly, CWI-MAPKs are associated with the formation of hyphopodia, which are infection structures required for C. fimbriata, and are reported for the first time in this work. Mutants lacking CWI-MAPK genes had defects in forming hyphopodia. The ability of mutants to penetrate cellophane membranes and host cells was reduced. CWI-MAPKs or CfSwi6 deletion affected CfSep4 assembly at penetration pegs, while CfSep4 was important for septin-ring and penetration peg formation. These results indicate that CWI-MAPKs regulate infection structure formation by modulating septin-ring organisation. RNA-seq analysis revealed that some downstream genes co-regulated by CfSlt2 and CfSwi6 are cellophane surface-induced genes. Knockout of PHH50197 and CfHSP30_1, two CfSlt2-CfSwi6-dependent genes, affected hyphopodium formation and pathogenicity. Additionally, other downstream genes, including PHH51274, CfHSP30_0, CfSTE11 and PHH55780, are not necessary for hyphopodium morphogenesis but are important for pathogenicity. Our study reveals a molecular mechanism by which CWI-MAPKs regulate pathogenicity through downstream genes mediated by CfSwi6 in C. fimbriata.

Abstract Citronellol is a kind of terpene produced by plants in response to external stress, thus can be used as a gas biomarker to detect black spot Ceratocystis fimbriata infection in sweetpotato. However, many contemporary analytical methods, exemplified by gas chromatography-mass spectrometry (GC-MS), are technically demanding, time-consuming, and require complex sample preparation procedures. In this study, a quartz crystal microbalance (QCM)-based gas sensor fabricated via a surface molecular imprinting technique was modified with a Co/Zn-ZIF@MIP composite, in which cobalt-zinc bimetallic ZIF (Co/Zn-ZIF) served as the support material. A linear relationship was observed between the frequency shift and citronellol concentrations ranging from 0.88 to 22 mg/L, with a sensitivity of –6.08 Hz/(mg·L) and a limit of detection (LOD) of 1.35 mg/L. This result indicated that this sensor has excellent selectivity for citronellol and demonstrates high repeatability, as evidenced by R² value of 0.97. In evaluations with real samples, the sensor reliably identified citronellol among the complex volatile organic compounds (VOCs) emitted from black spot-infected sweetpotato, indicating a high level of selectivity. Our research achieved the rapid characterization of sweetpotato black spot disease within 4 min and provided new insights into the development of QCM-based gas sensors for the rapid assessment of agricultural product quality and safety.

Abstract Ceratocystis wilt, caused by the fungus Ceratocystis fimbriata, is one of the most important problems in teak (Tectona grandis) production, negatively affecting yield and wood quality. In this study, we aimed to use whole-genome sequencing to identify single-nucleotide polymorphisms (SNPs) associated with teak resistance to the fungus C. fimbriata in T. grandis. The resistance of 130 teak genotypes to the fungus was evaluated using the bark substitution method, and lesion area was assessed at 120 dpi. Through genotyping-by-sequencing analysis, 1.4 million high-quality SNPs were obtained and used for genome-wide association studies via FarmCPU model. The model demonstrated a good fit for the data and showed high levels of significance for the identified SNP variations. We identified three candidate SNP variations linked to the lesion area trait associated with teak resistance to Ceratocystis wilt. Specifically, one SNP variation is located on pseudochromosome 2, while two SNP variations are found on pseudochromosome 15. These findings can be applied in teak breeding programs aimed at enhancing resistance to the fungus C. fimbriata, either by using resistant clones directly or by incorporating these SNPs as markers for assisted selection in breeding programs.

Sweet potato black rot caused by the pathogenic fungus Ceratocystis fimbriata is a destructive disease that can result in severe agricultural losses. This study explores the antifungal efficacy and underlying mechanisms of Bacillus licheniformis BL06 against C. fimbriata. The plate antagonism assay revealed that BL06 significantly suppressed the radial growth of C. fimbriata mycelia, achieving inhibition rates of 39.53%, 53.57%, 64.38%, and 69.11% after 7, 10, 13, and 16 days, respectively. In vivo experiments demonstrated that BL06-treated sweet potato tissues exhibited markedly smaller lesions than the control, indicating effective suppression of black rot. Microscopic observations indicated that BL06 treatment altered the morphology and activity of C. fimbriata mycelia, causing swelling and deformation. Additionally, BL06 markedly reduced spore production and germination in a dose-dependent manner, with complete inhibition observed at the highest concentrations tested. The cell-free supernatant (CFS) of BL06 was identified as the primary antifungal agent, achieving an inhibition rate of 76.11% on mycelial growth. Transcriptome analysis of C. fimbriata treated with BL06 CFS revealed significant downregulation of genes involved in cell wall and membrane biosynthesis, spore development, protein processing in the endoplasmic reticulum, and energy metabolism. These findings suggest that BL06 is a potent biocontrol agent against C. fimbriata, exerting its effects through multiple molecular pathways.

Abstract. Pratama R, Suwandi S, Muslim A, Mulawarman. 2025. Diversity of Ceratocystis fimbriata causing canker and wilt disease on Cupressus sempervirens (Italian cypress) in Indonesia. Biodiversitas 26: 278-287. In 2022-2023, new diseases were observed on Cupressus sempervirens in South Sumatra, Indonesia, with the disease incidence increasing from 17.6% to 26.5% in 2023. Initial symptoms, included stem cankers, black lesions on sapwood and vascular tissue, discoloration and partial wilting of leaves, and eventual complete drying, leading to plant death. The objective of this study was to isolate and identify the fungal pathogen causing wilt disease in C. sempervirens trees using morphological characterization and DNA sequencing. In 2022-2023, a disease survey was conducted in six districts of South Sumatra. The results showed that six out of ten locations were infected, with disease incidence ranging from 4.1% to 17.6% in 2022, increasing to 2% to 26.5% in 2023. Pathogen identification employed a polyphasic approach, combining morphological and molecular characteristics from specific genomic regions (the internal transcribed spacer (ITS) and ?-tubulin). Both the morphological features (including a globose base with a long neck-ended tip with ostiolar hyphae, cylindrical conidia, and hat-shaped ascospores) and phylogenetic analysis identified the isolates as Ceratocystis fimbriata. ITS gene sequences indicated that all the isolates belonged to the ITS5 haplotype. In pathogenicity test, pathogen caused mortality in C. sempervirens, Acacia mangium, and Artocarpus heterophyllus plants. The implications of these findings are significant, as they can potentially lead to the development of effective control measures. To our knowledge, this is the first report of Ceratocystis spp. causing wilt disease on C. sempervirens in South Sumatra.