Search Results (93)

Fusarium oxysporum f. sp. niveum is an increasingly threatening fungal pathogen that systemically colonizes watermelon plants and severely compromises their productivity by causing destructive vascular wilt disease. While its nonribosomal peptide synthetase NPS6 has been identified as a key virulence factor, the regulatory mechanisms through which it controls downstream gene networks to cause disease remain unclear. To elucidate this regulatory pathway, we constructed a ΔFW-NPS6 knockout mutant and conducted a comparative genome-wide analysis using RNA sequencing, with the wild-type strain as a control. The results revealed 66 NPS6-dependent differentially expressed genes, which were primarily associated with secondary-metabolite biosynthesis (e.g., genes encoding nonribosomal peptide synthetases like NPS2) and pathogen–host interactions (e.g., components of the MAPK signaling pathway), and were enriched in key pathogenic pathways. This finding reveals the virulence regulatory network mediated by NPS6, providing a direct theoretical foundation and crucial molecular targets for developing novel control strategies, such as targeted fungicides or genetic interventions, against Fusarium wilt in watermelon by highlighting NPS6 itself as a potential fungicide target and its downstream pathways (e.g., siderophore biosynthesis) as points for intervention. Full article

Verticillium wilt (VW) of cotton caused by the soilborne pathogen Verticillium dahliae is a major disease across cotton production worldwide. The disease can result in yield reductions up to 80% on some occasions. V. dahliae is an asexual fungus and belongs to a relatively small Verticillium genus in the Ascomycota, though both of the mating type idiomorphs are present within some populations. The diversity of V. dahliae is widely associated with vegetative compatibility groups (VCGs), of which six different VCGs are recognised. Of these, isolates belonging to VCGs 1, 2, and 4 are globally distributed and associated with a broad host range, including cotton. Approximately 400 plant species have been recorded as hosts of V. dahliae. The pathogenicity and virulence of V. dahliae in many cases are correlated with VCG designations and hosts of origin. Disease management of VW of cotton still relies on accurate, rapid detection and quantification of V. dahliae using both conventional and molecular approaches. The use of resistant cultivars is the most effective and economical control strategy; however, no cultivars confer complete resistance to the disease. Control strategies including cultural, biological, chemical, and induced-resistance approaches have indicated certain degrees of success in minimising disease damage and diminishing the build-up of pathogen inoculum. In this review, we discuss insights into the VW disease of cotton, and the associated pathogen and current control approaches, as well as future research perspectives. Full article

Verticillium wilt of olive (VWO), caused by the vascular soilborne fungus Verticillium dahliae, is one of the most devastating diseases of olive cultivation in the Mediterranean area. The adoption of tolerant genotypes is considered an efficient strategy to reduce its impact in the absence of effective chemical control. In the present study we assessed the response of seventy-seven olive cultivars (Olea europaea L.) to the defoliating pathotype of V. dahliae under controlled inoculation conditions. Five plants per cultivar were inoculated and compared with non-inoculated controls. Disease progression was monitored weekly for ten weeks and measured through three complementary parameters: Relative Area Under the Disease Progress Curve (RAUDPC), Final Mean Severity (FMS), and Percentage of Dead Plants (PDP). Statistical analyses, including ANOVA followed by Tukey’s HSD, correlation evaluation, and principal component analysis (PCA), were applied to classify cultivars into five susceptibility classes. Notable variability was observed among cultivars, with 7.8% classified as Highly Resistant (HR), 24.7% as Resistant (R), 46.8% as Moderately Susceptible (MS), and 20.8% as Susceptible (S) or Extremely susceptible (E). The cultivar Ghiacciolo showed the highest level of tolerance, displaying only slight symptoms and no statistically significant difference from the non-inoculated control, whereas ‘Carbuncion’, ‘Giogolino’, and ‘Pampagliosa’ exhibited more severe disease than the susceptible reference ‘Picual’. Strong correlations among RAUDPC, FMS, and PDP confirmed the consistency of the disease assessment framework, while PCA revealed distinct clustering patterns according to resistance level. Overall, these findings provide reliable evidence for the selection of olive cultivars suitable for areas vulnerable to V. dahliae. Full article

Banana and plantain crops are essential for food security; Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense (FOC), is one of the most devastating disease affecting these crops worldwide. The pathogen infects the radicular system and subsequently colonizes and collapses the vascular tissue, leading to wilting and plant death. The aims of our study were to determinate the chemical composition of the essential oil from Origanum vulgare obtained by hydro-distillation, and to evaluate its antifungal activity against FOC race 1. GC/MS analysis identified 31 compounds in the oil. Eugenol (76.3%) and D-Limonene (6.13%) were the main components. Antifungal activity was evaluated in vitro and OEO inhibited the mycelial growth of FOC race 1 at 500 µL L⁻¹. The minimum inhibitory concentrations (MIC₅₀ and MIC₉₅) were 111.1 and 174.1 µL L⁻¹, respectively. Fusarium wilt control evaluated in Silk banana vitroplants was analyzed by disease severity in the internal corm, controlled by oregano essential oil at 3000 µL L⁻¹. OEO treatments had no detrimental effects on Silk banana vitroplants. This paper provides knowledge to use oregano-derived compounds to develop bioproducts aimed at the integral and sustainable management of Fusarium wilt in banana and plantain crops. Full article

Management of invasive species is especially difficult when the organisms involved are endophagous and their interactions complex. Such is the case with laurel wilt disease (LWD), a lethal vascular condition caused by Harringtonia lauricola, the fungal symbiont of the non-native redbay ambrosia beetle (RAB), Xyleborus glabratus Eichoff (Coleoptera: Curculionidae). LWD has caused extensive mortality of coastal redbay, Persea borbonia, and is expanding to utilize additional lauraceous hosts, including sassafras, Sassafras albidum. Current management has not been successful in preventing its spread, warranting investigation into additional techniques. RNA interference (RNAi) is a highly specific gene-silencing mechanism used for integrated pest management of crop pests and currently being investigated for use in forests. When targeting essential genes, RNAi can cause rapid insect mortality. Here we focus on RAB, identifying for the first time species-specific reference genes for quantitative real-time PCR (qPCR) and assessing mortality and gene expression after oral ingestion of double-stranded RNAs (dsRNAs) targeting essential genes (hsp, shi, and iap). Our study validates reference genes for expression analyses and shows significant mortality and changes in gene expression for all three target genes. Our research aims to contribute to the development of innovative management strategies for this invasive pest complex. Full article

Background/Objectives: Fusarium wilt of cotton, caused by Fusarium oxysporum f. sp. vasinfectum (FOV), is a destructive vascular disease that severely impacts cotton production. Among its variants, race 4 (FOV4) is especially aggressive, leading to early season stand losses and yield reductions. While resistant cultivars of Gossypium barbadense (pima cotton) have been developed, the molecular basis of this resistance remains unclear. This study aimed to characterize transcriptomic responses associated with FOV4 resistance in pima cotton. Methods: We conducted an in vitro infection assay using two G. barbadense cultivars with contrasting phenotypes: the highly resistant ‘DP348RF’ and the highly susceptible ‘GB1031’. Root tissues were sampled at multiple stages of infection, and RNA sequencing was performed to identify differentially expressed genes and pathways contributing to resistance. Results: Resistant plants ‘DP348RF’ showed strong induction of genes related to reactive oxygen species (ROS) metabolism, chitinase activity, and lignification compared to the susceptible cultivar. Notably, genes involved in the biosynthesis and reinforcement of the Casparian strip, a critical biochemical barrier limiting pathogen penetration into vascular tissues, were uniquely and significantly upregulated in resistant roots. These transcriptional responses suggest that fortification of cell wall barriers and enhanced antimicrobial defenses contribute to effective restriction of FOV4 colonization. Conclusions: Our findings identify a distinct molecular signature of resistance to FOV4 in pima cotton, with Casparian strip reinforcement emerging as a potential mechanism limiting vascular infection. These insights provide a foundation for breeding strategies aimed at improving Fusarium wilt resistance in cotton. Full article

Fusarium wilt, caused by Fusarium oxysporum f. sp. ciceris (Foc), is a devastating disease of chickpea (Cicer arietinum L.), leading to vascular necrosis and plant death. This study evaluated 120 chickpea genotypes under natural infection field conditions during spring sowing in southeastern Kazakhstan, assessing disease incidence (DI) and severity (DS) to identify resistant germplasm. Molecular screening using eight SSR markers linked to Foc-1, Foc-2, Foc-3, and Foc-5 loci detected resistant alleles in 18, 26, 19, and 42 genotypes, respectively. The correlation between molecular marker data and phenotypic resistance evaluations confirmed UBC-170 (Foc-2) and TA-194 (Foc-5) as the most predictive diagnostic markers (p < 0.01). Ten genotypes showed complete disease resistance (DI < 5%, R), corresponding to the resistant control (cultivar “WR-315”), with confirmed presence of multiple Foc resistance genes. The results of this study revealed valuable genetic resources for marker-assisted breeding programs aimed at developing Fusarium wilt-resistant chickpea cultivars adapted to Central Asian agroclimatic conditions. Full article

Fig (Ficus carica) orchards in the Salento peninsula (southeastern Apulia region, Italy) are increasingly affected by decline syndromes whose etiology remains poorly resolved. In this paper, we provide a first characterization of a complex disease outbreak, integrating field surveys, fungal isolation, molecular phylogenetics, and pathogenicity assays. Symptomatic trees displayed chlorosis, defoliation, cankers, vascular discoloration, and wilting, frequently associated with bark beetle galleries. Mycological analyses revealed a diverse assemblage of fungi, dominated by Botryosphaeriaceae (including Neofusicoccum algeriense, and Lasiodiplodia theobromae), the Fusarium solani species complex (notably Neocosmospora perseae), and Ceratocystis ficicola. While C. ficicola was isolated with lower frequency, its recovery from adult beetles—including Cryphalus dilutus—supports a role in insect-mediated dissemination in addition to soilborne infection. Pathogenicity tests demonstrated that N. algeriense and N. perseae, together with C. ficicola, caused severe vascular lesions and wilting, confirming their contribution to fig decline. By contrast, other Fusarioid strains showed no pathogenicity, consistent with their role as latent or stress-associated pathogens. This study provides the first evidence that N. algeriense and N. perseae act as pathogenic agents on fig, highlights their interaction with C. ficicola within a multifactorial decline syndrome, and identifies dual epidemiological pathways involving both soil/root infection and insect-facilitated dissemination via beetles such as C. dilutus. These findings redefine fig decline in the Salento peninsula (southern Italy) as a multifactorial disease rather than a single-pathogen outbreak, with significant implications for diagnosis, epidemiology, and integrated management strategies. Full article

The soil-borne fungal pathogen Verticillium dahliae causes devastating vascular wilt disease in numerous crops, including cotton. In this study, we reveal that VdSOX1, a highly conserved sarcosine oxidase gene, is significantly upregulated during host infection and plays a multifaceted role in fungal physiology and pathogenicity. Functional deletion of VdSOX1 leads to increased fungal virulence, accompanied by enhanced microsclerotia formation, elevated carbon source utilization, and pronounced upregulation of effector genes, including over 50 predicted secreted proteins genes. Moreover, the VdSOX1 knockout strains suppress the expression of key defense-related transcription factors in cotton, such as WRKY, MYB, AP2/ERF, and GRAS families, thereby impairing host immune responses. Transcriptomic analyses confirm that VdSOX1 orchestrates a broad metabolic reprogramming that links nutrient acquisition to immune evasion. Our findings identify VdSOX1 as a central regulator that promotes V. dahliae virulence by upregulating effector gene expression and suppressing host immune responses, offering novel insights into the molecular basis of host–pathogen interactions and highlighting potential targets for disease management. Full article

Watermelon (Citrullus lanatus), a vital economic crop, is severely threatened by Fusarium wilt (FW), which is caused by the soil-borne fungal pathogen Fusarium oxysporum f. sp. niveum (Fon). To elucidate the molecular mechanisms underlying FW resistance in watermelon, we tracked the infection process via microscopy, identifying three critical time points (1, 6, and 8 days post-inoculation) corresponding to spore germination, hyphal invasion of the xylem vascular system, and symptom onset, respectively. Transcriptional profiling at these stages revealed six disease-resistance-associated gene modules through differential expression analysis, expression pattern clustering, weighted gene co-expression network analysis, and functional enrichment. These modules exhibited strong correlations with distinct infection phases. Protein–protein interaction networks identified 35 hub genes, including receptor-like kinases; WRKY and ethylene-responsive factor transcription factors; and genes involved in cell wall reinforcement, hormone signaling, defense metabolism/detoxification, programmed cell death regulation, and antimicrobial compound biosynthesis. Differential expressions of these genes across infection stages likely underpin the observed phenotypic disparities. Five hub regulatory genes were identified by quantitative real-time PCR in the SRgreen and SRblack modules, namely, Cla97C01G014990 (WRKY transcription factor 42), Cla97C02G042360 (calcium-transporting ATPase), Cla97C08G155710 (AIG2), Cla97C09G170380 (ethylene-responsive factor 1B-like), and Cla97C06G121810 (receptor kinase, putative). These genes mediate early rapid defense responses via SRgreen and sustain long-term resistance through SRblack. By validating the expression patterns of hub genes, the study elucidated the watermelon resistance response and provided insights into transcriptional regulation during different stages of Fon–watermelon interactions. Additionally, it identified candidate genes that could enhance watermelon resistance to wilt disease. Full article

Background: Verticillium wilt, which is a soil-borne vascular disease, causes serious economic losses worldwide. Various toxins secreted by V. dahliae are key factors that lead to wilt symptoms. Methods: The Vd-toxins CIA, indazole, and 3ICD were labeled with fluorescence groups, respectively, to observe the transport pathway. Transcriptome sequencing and qRT-PCR were employed to assess the expression patterns under Vd-toxin treatment. Results: AtALA1 and AtALA7 were up-regulated by V. dahliae and LC-toxins, and overexpression of either AtALA1 or AtALA7 increased Arabidopsis resistance against LC-toxins. Overexpression of AtALA1 improved the resistance of Arabidopsis to 4MBA, 3ICD, and indazole, while AtALA7 enhanced resistance to 4MBA, 3ICD, and CIA. AtALA7-overexpressing plants showed a stronger capability to transport CIA^FITC and 3ICD^5-FAM into vacuoles, while AtALA1-overexpressing plants accumulated indazole^5-FAM and 3ICD^5-FAM. Aggregation of AtALA1 and AtALA7 enhances the resistance of plants to V. dahliae. Conclusions: Arabidopsis P4-ATPase genes AtALA1 and AtALA7 mediated cell detoxification by transporting different Vd-toxins to vacuoles for degradation, thereby increasing resistance to Verticillium wilt. Full article

Fusarium wilt in bitter gourd caused by Fusarium oxysporum f. sp. momordicae (Fomo) is a severe plant disease that affects the world’s bitter gourd (Momordica charantia L.) cultivation. This study evaluated nine luffa hybrids for their performance as rootstocks with bitter gourd to control Fusarium oxysporum f. sp. luffae (Folu) isolate Fomh16 and Fomo isolate Fomo33. In the first evaluation, five hybrids (LF1, LF2, LF3, LF15, and LF16) exhibited resistance to the Fomh16 isolate and showed no symptoms. One hybrid, LF10, was resistant with a mean disease rating (MDR) of 0.9 at 28 days post-inoculation (dpi). Seven luff hybrids that displayed resistant and moderate resistance in the first evaluation were used as rootstocks with susceptible bitter gourd cultivars. Five rootstocks exhibited high resistance to Fomh16 and Fomo33 isolates, with their MDR ranging from 0.0 to 0.7. In addition, the findings revealed that both isolates could colonize the vascular bundle of all resistant luffa rootstocks at 28 dpi. However, the Fomo33 isolate could extend and colonize the vascular bundle of bitter gourd scion when grafted only with rootstock LF5 and LF11. The quantitative PCR results indicated that there were significant differences in the amount of the Fomo33 DNA between the bitter gourd grafted onto LF15 and LF16 rootstocks and the self-grafted plants; however, the pathogen cannot be detected in the bitter gourd scions grafted with resistant rootstocks. These findings provide valuable resistant sources that can be used as rootstocks to manage Fusarium wilt disease in bitter gourd. Full article

The olive tree is one of the most important fruit crops grown in Morocco, yet extensive decline associated with the root rot of this crop has been observed in many regions. This study aimed to identify and characterize the oomycetes associated with root rot disease in olive trees. During the 2021 and 2022 growing seasons, symptomatic root tissues and soil samples were collected for isolation. Based on morphological traits and the sequencing of the internal transcribed spacer (ITS) region of rDNA, 10 oomycete species were identified, belonging to the Phytophthora and Pythium sensu lato (s.l.) genera. Seven species were assigned to Phytophthora, namely, P. palmivora, P. plurivora, P. acerina, P. oleae, P. cactorum, P. gonapodyides, and P. megasperma. The Pythium s.l. genus was represented by three species, including P. schmitthenneri, P. aphanidermatum, and P. irregulare. A pathogenicity assay was conducted by soil infestation to evaluate the effect of these pathogens on one-year-old olive saplings (var. Picholine Marocaine). Results revealed that all 10 species were pathogenic to olive saplings. Inoculated saplings exhibited symptoms, such as root rot, vascular discoloration, and wilting. The pathogens were successfully re-isolated from necrotic roots, thereby fulfilling Koch’s postulates. These findings highlight the complex etiology of root rot disease in olive trees, as multiple species can induce similar symptoms. This study represents the first detailed report of Phytophthora and Pythium s.l. species associated with olive root rot disease in Morocco. Full article

Verticillium wilt and Fusarium wilt cause significant losses in cotton (Gossypium hirsutum) production and have a significant economic impact. This study determined the functional role of GhSTR1, a member of the ABCG subfamily of ATP-binding cassette (ABC) transporters, that mediates cotton defense responses against various plant pathogens. We identified GhSTR1 as a homolog of STR1 from Medicago truncatula and highlighted its evolutionary conservation and potential role in plant defense mechanisms. Expression profiling revealed that GhSTR1 displays tissue-specific and spatiotemporal dynamics under stress conditions caused by Verticillium dahliae and Fusarium oxysporum. Functional validation using virus-induced gene silencing (VIGS) showed that silencing GhSTR1 improved disease resistance, resulting in milder symptoms, less vascular browning, and reduced fungal growth. Furthermore, the AtSTR1 loss-of-function mutant in Arabidopsis thaliana exhibited similar resistance phenotypes, highlighting the conserved regulatory role of STR1 in pathogen defense. In addition to its role in disease resistance, the mutation of AtSTR1 in Arabidopsis also enhanced the vegetative and reproductive growth of the plant, including increased root length, rosette leaf number, and plant height without compromising drought tolerance. These findings suggest that GhSTR1 mediates a trade-off between defense and growth, offering a potential target for optimizing both traits for crop improvement. This study identifies GhSTR1 as a key regulator of plant–pathogen interactions and growth dynamics, providing a foundation for developing durable strategies to enhance cotton’s resistance and yield under biotic and abiotic stress conditions. Full article

Strawberries are planted globally as an important crop. Fusarium oxysporum f. sp. fragariae (Fof), a haploid mitosporic, pathogenic fungus with obvious host specificity, is responsible for an economically devastating soil-borne disease seriously threatening strawberry. Fusarium oxysporum is distributed in soils worldwide and causes vascular wilt and root rot disease in over 100 plant species. However, the formae speciales of F. oxysporum commonly have a very narrow host range, often restricted to a single host plant species. We isolated and identified pathogenic F. oxysporum from diseased strawberry samples collected from different provinces in China. Further analysis showed that among the 55 F. oxysporum isolates, only 70.91% belonged to Fof, and the remaining 29.09% were named Fo. The mycelial growth of Fof was faster than that of Fo at 20, 30, and 35 °C. The sporulation ability of Fof was weaker than that of Fo, and Fof presented a significantly higher germination rate under high temperatures. Fof and Fo from strawberry were not pathogenic to tomato or cucumber plants, and Fof showed significantly higher pathogenicity on strawberry than Fo. To explore the pathogenic mechanism of Fof, we knocked out SIX10 in Fof. The mycelial growth rate of ΔFofSIX10 was significantly slower than that of the wild type, but there were no significant differences in spore production. The pathogenicity of ΔFofSIX10 to strawberry was significantly weakened, showing decreased severity of symptoms, indicated by root and crown rot, and wilt. Our research provides a basis for understanding the interaction between F. oxysporum and the host strawberry and the occurrence and management of Fusarium disease on strawberry. Full article