Search Results (53)

Fusarium circinatum poses severe threats to agroforestry ecosystem as a globally significant pathogenic fungus. This study utilized multi-source species distribution data and environmental variables (climatic, topographic, and soil factors) to predict the global potential habitat suitability of F. circinatum and its response to future climate change using an optimized MaxEnt model (RM = 1, FC = LQ). The results indicate that the current total suitable area spans approximately 69.29 million km², with highly suitable habitats (>0.493) accounting for 15.07%, primarily concentrated in East Asia, southwestern North America, western South America, the Mediterranean coast, and eastern Australia. The distribution of F. circinatum’s suitable habitats is primarily constrained by the following environmental factors, ranked by contribution rate: coldest quarter precipitation (29.4%), coldest quarter mean temperature (18.2%), annual mean temperature (17.2%), and annual precipitation (12%). Under future climate scenarios, the suitable habitats exhibited an overall contraction and poleward shift, with the most significant decline in highly suitable areas observed under SSP370-2050s (−52.1%). The centroid of suitable habitats continuously migrated northwestward from Gombe State, Nigeria, with the maximum displacement reaching 1077.6 km by SSP585-2090s. This study reveals a latitude gradient redistribution pattern of F. circinatum driven by climate warming, providing a scientific basis for transboundary biosecurity and early warning systems. Full article

Ruta graveolens L. has been described as possessing antifungal and nematicidal activity. Among the bioactive compounds present in this plant, alkaloids and furanocoumarins have attracted considerable attention. The aim of this study was to evaluate the in vitro biological activity of extracts from rue enriched in bioactive compounds against Fusarium oxysporum, F. circinatum, and Meloidogyne incognita, and to correlate the chemical profile of the extracts with their biological activities. Six extracts with contrasting chemical profiles, obtained by pressurized liquid extraction and supercritical fluid extraction using green solvents, were selected for biological evaluation. The highest F. oxysporum growth inhibition was achieved with the extracts enriched in fatty acids and furanocoumarins at concentrations of 4, 8, and 16 mg/mL, while for F. circinatum, the highest growth inhibition was obtained using the extract enriched in terpenes at 16 mg/mL; moreover, the six extracts evaluated caused mortality in M. incognita. Therefore, enriched extracts of R. graveolens might be considered as an alternative for pathogen control on economically important crops such as potatoes, tomatoes, and onions, among others. Correlations between biological activities and chemical compositions suggest the importance of fatty acids against F. oxysporum, fatty acids and terpenes against F. circinatum, and alkaloids, coumarins, and furanocoumarins for M. incognita. Full article

Mycoviruses are viruses that infect fungi, including plant pathogens. The infection of these mycoviruses is sometimes associated with impaired phenotypes of their fungal hosts, a phenomenon known as hypovirulence. Thus, using mycoviruses as biological control agents has emerged as a promising tool to combat forest diseases. The invasive ascomycete fungus Fusarium circinatum, which causes pine pitch canker (PPC) disease in Pinus tree species and other coniferous trees, is infected by the mycovirus Fusarium circinatum mitovirus 1 (FcMV1), FcMV2-1, and FcMV2-2. However, its impact on pathogen fitness remains unclear. The most accurate method used to identify the effect of a mycovirus on its host is the generation of isogenic lines with and without the mycovirus. The present study aimed to cure F. circinatum isolates infected by FcMV1 using different approaches. For this purpose, three replicates of each isolate were exposed to thermal treatment (38 °C) and antibiotic treatment (ribavirin, cycloheximide, kanamycin, and rifampicin mixed with cAMP)(cyclic adenosine monophosphate) for five successive passages. The viral titer of FcMV1 was then assessed using qPCR (quantitative polymerase chain reaction) after the first week and after the fifth week of the treatment. The results revealed differences in treatment efficacy among F. circinatum isolates, with some showing very low virus titers at the end of the experiment. Both thermal and antibiotic treatment effectively reduced the viral load in all isolates. In addition, the antibiotic cycloheximide and rifampicin +cAMP reduced the viral titer more than ribavirin and kanamycin. The isolate Fc179 was found to be more prone to antibiotic treatment than the other two isolates (001 and Va221). This study demonstrated the possibility of using some isolates of F. circinatum for fine-tuning cures for mitovirus, in order to create virus-free strains for biological control in the future. Full article

Malesherbia auristipulata is an endemic plant species of the Atacama Desert, with unique morphological and physiological adaptations. This research was conducted at Cuesta El Águila, Arica and Parinacota Region, Chile. Adult and juvenile plants were monitored, recording their growth, flowering, and fruiting phases. Additionally, plant community species were identified. For the study of endophytic mycoflora, samples of seeds, roots, stems, and leaves were collected, disinfected, and cultivated in specific media. The isolated fungi were analyzed morphologically and molecularly, determining their distribution in different plant organs. The diversity of endophytic fungi associated with M. auristipulata and the associated fungal community was determined. The presence of endophytic fungi varied depending on the organ studied, suggesting dynamic interactions in the structure of its fungal community. Among the identified endophytic fungi, Alternaria sorghi, A. alstroemeriae, and Fusarium nurragi stand out for their presence in the root and stem of the plant. Of particular interest is the presence of F. circinatum in the leaves. This study provides valuable information for the conservation of M. auristipulata and other organisms in the Atacama Desert, highlighting the importance of ecological interactions in the resilience of plants to extreme environmental conditions. Full article

This study addresses the challenge of finding novel ways to solubilize phosphorus and zinc for agricultural purposes. The aim was to isolate PSMs (phosphorous-solubilizing microbes) and ZnSMs (zinc-solubilizing microbes) from different environments (e.g., soil amendments, land uses, and crop rotation systems) and evaluate their ability to solubilize different insoluble P sources (e.g., β-tricalcium phosphate (β-TCP), calcium-phytate (CaP), and rock phosphate (RP)) and Zn sources (e.g., zinc carbonate (ZnC), zinc oxide (ZnO), and zinc phosphate (ZnP)). Here, 25 isolates capable of solubilizing either P or Zn sources were isolated and classified by species using 16S rRNA and ITS-region sequencing. Notably, Aspergillus awamori, Fusarium circinatum, Fusarium longifundum, and Mucor circinelloides, isolated from cultivated soils and soil amendments, emerged as the most efficient PSMs and ZnSMs. Mucor circinelloides exhibited the highest solubilization ability for broths containing β-TCP, CaP, RP, ZnO, and ZnP, with log2-fold changes of 3.7, 1.8, 8.9, 7.8, and 2.4, respectively, compared to the control. For ZnC and ZnO, Aspergillus awamori displayed the highest Zn solubilization, with a 2.1 and 3.0 log2-fold change. The study highlights the potential of these strains as biofertilizers and underscores the role of Mucor and Fusarium genera in zinc solubilization. Full article

Fusarium circinatum, the causative agent of pine pitch canker disease, is a pathogenic fungus that poses a significant threat to pine forests globally. It infects various Pinus species, causing resinous cankers, needle discoloration, and tree death. The disease severely impacts forest ecosystems, necessitating cost-effective and environmentally friendly management strategies. Contaminated pine seeds and seedlings are the main pathways for introducing this fungus to disease-free areas. To mitigate this disease and prevent its spread, it is crucial to implement new processes in forest plant production systems that align with the existing conditions of forest nurseries, ensuring effective and sustainable management. With this in mind, a national collaborative study involving 14 Portuguese partners was initiated to develop new prevention and mitigation strategies. In this work, four different treatments—MennoFlorades, Captan, ethanol, and hot water—were tested for their ability to eliminate F. circinatum from contaminated Pinus seeds in vitro. The most effective treatments were selected for further in vitro assays and real-context nursery germination trials to assess their impacts on seed germination, plant production, and certification. MennoFlorades, Captan, and hot water were tested in the nursery, with hot water showing the most promising results due to its negligible impact on seedlings, eco-friendly nature, ease of implementation, and cost-effectiveness. These findings offer promising prospects for preventing pine pitch canker outbreaks in nurseries and, consequently, in forests. Full article

In ascomycetous fungi, sexual mate recognition requires interaction of the Ste2 receptor protein produced by one partner with the α-factor peptide pheromone produced by the other partner. In some fungi, Ste2 is further needed for chemotropism towards plant roots to allow for subsequent infection and colonization. Here, we investigated whether this is also true for the pine pitch canker fungus, Fusarium circinatum, which is a devastating pathogen of pine globally. Ste2 knockout mutants were generated for two opposite mating-type isolates, after which all strains were subjected to chemotropism assays involving exudates from pine seedling roots and synthetic α-factor pheromone, as well as a range of other compounds for comparison. Our data show that Ste2 is not required for chemotropism towards any of these other compounds, but, in both wild-type strains, Ste2 deletion resulted in the loss of chemotropism towards pine root exudate. Also, irrespective of mating type, both wild-type strains displayed positive chemotropism towards α-factor pheromone, which was substantially reduced in the deletion mutants and not the complementation mutants. Taken together, these findings suggest that Ste2 likely has a key role during the infection of pine roots in production nurseries. Our study also provides a strong foundation for exploring the role of self-produced and mate-produced α-factor pheromone in the growth and overall biology of the pitch canker pathogen. Full article

Radiata pine is one of the most commonly planted tree species in Chile due to its fast growth and desirable wood and pulp properties. However, its productivity is hampered by several diseases. Pitch canker disease (PCC) caused by Fusarium circinatum, is considered the most damaging disease to the pine forest industry. Several control measures have been established, with biological control emerging as an environmentally friendly and effective way for F. circinatum control. Previous studies support the value of Clonostachys rosea in reducing PCC damage, with evidence suggesting a potential induced systemic resistance (ISR) triggered in radiata pines by this agent. Ten-month-old radiata pine plants were pre-treated with C. rosea on a substrate at 8 and 1 days before inoculation with F. circinatum on the stem tip, and expression levels were determined for DXS1, LOX, PAL, and PR3 genes 24 h later. Lesion length was 45% lower on plants pre-treated with C. rosea and infected with F. circinatum compared to non-pre-treated and infected plants. Additionally, LOX and PR3 were induced 23 and 62 times more, respectively, in comparison to untreated plants. Our results indicate that C. rosea causes an ISR response in pre-treated plants, significantly increasing the expression of resistance genes and reducing lesion length. Full article

Pine pitch canker, caused by the ascomycete Fusarium circinatum, poses a substantial threat to pine trees and Douglas firs (Pseudotsuga menziesii), and has been identified as a pervasive issue in forests and nurseries worldwide, particularly in regions where susceptible conifers are cultivated. Given its prevalence in the Iberian Peninsula, assessments of the susceptibility of diverse European provenances of Scots pine (Pinus sylvestris)—specifically those from Poland, Lithuania, and Ukraine—have been conducted. Preliminary evaluations of Polish provenances have raised concerns about the potential threat to Scots pine stands in Poland posed by pitch canker. Under controlled conditions, we examined the impact of F. circinatum inoculation on the survival of seeds and seedlings from ten provenances of Scots pine. In response, the initial assessment of F. circinatum pathogenicity was undertaken in a controlled greenhouse environment. This evaluation uncovered a heightened susceptibility of pine seedlings to pitch canker among the tested provenances. Notably, one Lithuanian provenance demonstrated superior resistance to pitch canker, while two Polish provenances exhibited a higher prevalence of symptomless seedlings. These findings underscore the need for further exploration and identification of resilient individuals within these provenances, offering valuable insights for developing strategies to mitigate the impact of pitch canker on Scots pine in Europe. Full article

The pine pitch canker pathogen, Fusarium circinatum, is globally regarded as one of the most important threats to commercial pine-based forestry. Although genome sequences of this fungus are available, these remain highly fragmented or structurally ill-defined. Our overall goal was to provide high-quality assemblies for two notable strains of F. circinatum, and to characterize these in terms of coding content, repetitiveness and the position of telomeres and centromeres. For this purpose, we used Oxford Nanopore Technologies MinION long-read sequences, as well as Illumina short sequence reads. By leveraging the genomic synteny inherent to F. circinatum and its close relatives, these sequence reads were assembled to chromosome level, where contiguous sequences mostly spanned from telomere to telomere. Comparative analyses unveiled remarkable variability in the twelfth and smallest chromosome, which is known to be dispensable. It presented a striking length polymorphism, with one strain lacking substantial portions from the chromosome’s distal and proximal regions. These regions, characterized by a lower gene density, G+C content and an increased prevalence of repetitive elements, contrast starkly with the syntenic segments of the chromosome, as well as with the core chromosomes. We propose that these unusual regions might have arisen or expanded due to the presence of transposable elements. A comparison of the overall chromosome structure revealed that centromeric elements often underpin intrachromosomal differences between F. circinatum strains, especially at chromosomal breakpoints. This suggests a potential role for centromeres in shaping the chromosomal architecture of F. circinatum and its relatives. The publicly available genome data generated here, together with the detailed metadata provided, represent essential resources for future studies of this important plant pathogen. Full article

Native wild yeasts from forest ecosystems represent an interesting potential source of biocontrol organisms in synergy with disease-tolerant forest materials. Yeasts have a combination of competitive mechanisms and low requirements for their biotechnological application as biocontrol agents. The current study aimed to increase the number of biocontrol candidates against Fusarium circinatum and Diplodia sapinea. The enzymatic and antagonistic activities of the biocontrol candidates were evaluated using different screening methods, in which the direct impact on the growth of the pathogen was measured as well as some properties such as cellulose and lignin degradation, tolerance to biocides, volatile compound production, or iron effect, which may be of interest in biotechnological processes related to the management of forest diseases. A total of 58 yeast strains belonging to 21 different species were obtained from oak forest and vineyard ecosystems and evaluated. The application of yeast treatment behaved differently depending on the pathogen and the plant clone. The 2g isolate (Torulaspora delbrueckii) showed the highest inhibitory activity for D. sapinea and 25q and 90q (Saccharomyces paradoxus) for F. circinatum. Clones IN416 and IN216 were the most susceptible and the most tolerant to D. sapinea, respectively, while the opposite was observed for F. circinatum. Full article

Overgrazing leads to the degradation of grazing lands, which seriously threatens the stability of grassland ecosystems. Root-invading fungi, as one of the main influencing factors, can cause plant diseases in grasslands, reduce the proportion of dominant plant species, increase the proportion of invasive poisonous weeds, and further aggravate degradation. In order to predict and improve the effects of root-invading fungi on grassland degradation, we conducted an in situ soil indoor control experiment using soils collected from non-degraded, moderately degraded, and severely degraded areas of Nanshan pasture in Hunan Province, China. We used monoculture or mixed grasslands of dominant plant species, including Lolium perenne, Trifolium repens, and the invasive weed Persicaria hydropiper, and inoculated them with local strains of pathogenic Fusarium species (Fusarium boothii and Fusarium circinatum) and beneficial fungi Arbuscular Mycorrhizal Fungi (AMF) and Trichoderma hamatum to explore how different strains of fungi affect plant growth and community dynamics. The results showed that Fusarium species (Fusarium boothii and Fusarium circinatum), as a major pathogenic fungus, inhibited the growth of the dominant grass Lolium perenne in moderately and severely degraded soils, which provided growth space and resources for invasive weeds Persicaria hydropiper and further aggravated the degree of grassland degradation. However, the collaborative effect of beneficial fungi (AMF and Trichoderma) and their inhibitory effect on Fusarium species (Fusarium boothii and Fusarium circinatum) could promote the growth of dominant plants and weeds in soils with varying degrees of degradation, which is beneficial to maintaining the stability and diversity of grassland plant communities. The collaborative effect of beneficial fungi could also increase the availability of nutrients in severely degraded soils. Therefore, using beneficial fungi (AMF and Trichoderma) for soil improvement and reducing the harm of pathogenic Fusarium species (Fusarium boothii and Fusarium circinatum) to plant growth is of great significance for promoting the protection and management of grassland ecosystems, as well as for the restoration and recovery of grasslands. Full article

Fusarium circinatum causes pine pitch canker (PPC) disease and associated symptoms such as resinous lesions, mechanical weakness, and crown dieback that may lead to mortality in Pinus and Pseudotsuga spp. There are no ameliorative techniques available for the disease, and the genetic resistance among populations to support commercial plantation deployment has not been well characterized. In this study, we characterize the genetic control of PPC disease tolerance (and/or resistance) and predict the tolerance of families in existing breeding populations: open-pollinated (OP) half-sib and control-pollinated full-sib (FS) slash pine (Pinus elliottii var. elliottii Engelm.), OP loblolly pine (Pinus taeda L.), and advanced-generation OP hybrid slash × P. caribaea (Pinus elliottii var. elliottii Engelm. × Pinus caribaea var. bahamensis, caribaea, and hondurensis) using F. circinatum isolates obtained from three locations in Georgia and FL, USA. We describe a new experimental design that improves the accuracy of breeding value predictions, provides more precise genetic parameter estimates, and facilitates comparisons within and among taxa as well as comparisons among isolates. We found strong evidence for genetic control of the ratio of stem damage by F. circinatum, especially in slash pine and slash × P. caribaea hybrids. Loblolly and slash × P. caribaea hybrids exhibited less damage than slash pine. We observed a spectrum of virulence among F. circinatum isolate sources, which were not equally virulent in different pine taxa. Full article

The genus Fusarium comprises more than 300 species, and many of them are pathogens that cause severe diseases in agricultural, horticultural and forestry plants in both antropogenic and natural ecosystems. Because of their importance as plant pathogens, the genomes of several Fusarium spp. have been sequenced. Within this genus, Fusarium circinatum is one of the most harmful pathogens of pine trees attacking up to 60 Pinus species. Till now, the genomes of 13 strains of F. circinatum have been sequenced. The strain GL1327 we studied lacks a twelfth chromosome, which allows the study of virulence genes on this chromosome. Although the genome of several strains of F. circinatum has been sequenced, it is still almost completely unannotated, which severely limits the possibilities to further investigate the molecular mechanisms of virulence of Fusarium. Therefore, this study aimed to annotate the 12th chromosome of F. circinatum and integrate currently available resources. In silico annotation of the 12th chromosome of F. circinatum revealed the presence of 118 open reading frames (ORFs) encoding 141 proteins which were predicted using an ab initio gene prediction tool. The InterProScan and SMART analyses identified known domains in 30 proteins and eggNOG additionally in 12 of them. Among them, four groups can be distinguished: genes possibly related to heterokaryon incompatibility (4 genes), regulation of transcription (5 genes), plant cell wall degrading enzymes (7 genes) and trichothecene synthesis (3 genes). This study also integrated data of F.circinatum reference strain CMWF1803 assembled to chromosome level but not annotated with currently best annotated but assembled only to scaffold level strain NRRL 25331. Full article

Fusarium circinatum is one of the many threats to forests and Pinus nurseries all over the world, being classified as a quarantine organism by several organizations and governing bodies, such as the European and Mediterranean Plant Protection Organization (EPPO) and the European Union (EU), with associated phytosanitary measures in place to prevent its spread through the various means of dispersal. One such means of dispersal is the water used for irrigation in nurseries, which can contain fungal propagules. Three different treatments, namely, Desogerme, Intra Hydrocare and sodium hypochlorite (NaClO), were tested for their efficacy in eliminating F. circinatum spores in water at several concentrations. Those that showed 100% disinfection rates were selected for further assays regarding seed germination and water quality impact. From these studies, Desogerme 1% and Intra Hydrocare 4% were then selected for large-scale seed germination and plant certification assays in nurseries, where they showed promising results in regard to the prevention of infections in nurseries, and in this way, contribute to the efforts of mitigating this disease. Full article