Search Results (230)

Sacha inchi (Plukenetia volubilis) is a high-value crop due to its high content of omega-3 fatty acids and its outstanding nutritional, pharmaceutical, and cosmetic properties. However, this species faces challenges from diseases, particularly root rot. In this study, we identified one of the causal agents of root rot in sacha inchi using morphological observations, molecular methods, and pathogenicity tests. The pathogen was isolated from root tissues showing symptoms of Fusarium infection, observed in a plot in the Picota province. Morphological identification, DNA sequencing, and phylogenetic analysis using the ITS and TEF-1α markers revealed that the isolate causing root rot was Fusarium suttonianum (FSSC 20). Analysis of the PQ636870 (ITS) and PQ639345 (TEF-1α) sequences in the NCBI database, together with phylogenetic analysis, revealed 99.58% and 99.51% similarity with the ITS and TEF sequences, respectively, corresponding to F. suttonianum. Pathogenicity tests confirmed that this species induced the same symptoms observed in the field, fulfilling Koch’s postulates. This study represents the first report of F. suttonianum as a pathogen causing root rot in sacha inchi in Peru. This finding is critical for developing effective strategies for disease management and control, contributing to the sustainability and improvement of sacha inchi production in the region. Full article

The application of biochar and beneficial microorganisms has gained attention as a sustainable strategy to enhance soil health and plant resistance to pathogens. Trichoderma spp. play critical roles in nutrient mobilization, rhizosphere colonization, and suppression of soilborne diseases. However, little is known about the interactive effects of biochar and Trichoderma on the suppression of Fusarium equiseti (P1I3)-induced root rot in grapevine seedlings. In this study, we investigated the effects of two Trichoderma aureoviride strains (URM 6668 and URM 3734), with and without grapevine pruning-derived biochar (BVP), on disease severity, plant growth, and soil properties. Our results revealed that the combination of biochar and Trichoderma significantly reduced disease incidence and promoted biomass accumulation. Notably, BVP and T. aureoviride URM 3734 were the most effective at reducing leaf disease severity, resulting in a 53% decrease. Conversely, the combination of BVP and T. aureoviride URM 6668 led to the greatest reduction in root disease severity, with a 56% decrease. These findings suggest a synergistic relationship between biochar and beneficial fungi, reinforcing the role of organic soil amendments in promoting plant health. The integrated use of biochar and Trichoderma strains offers a viable, environmentally sound approach for managing grapevine root rot and enhancing seedling health in sustainable viticulture systems. Full article

Fusarium culmorum is the causal agent of root rot and crown rot in soft wheat. The aim of this study was to investigate the control mechanism of Talaromyces pinophilus HD25G2 as a biocontrol agent against F. culmorum. This involved the isolation and molecular identification of Fusarium and Talaromyces strains from soft wheat. The assay included the inhibition test of F. culmorum mycelial growth on potato dextrose agar and soft wheat media at two water activity values (0.98 and 0.95), its production of mycotoxins, and the fungal cell wall-degrading enzymes implicated in the antagonistic effect of T. pinophilus. The results showed that T. pinophilus and its extract free of cells reduced the growth of F. culmorum by over 55%. Interestingly, the T. pinophilus HD25G2 showed high chitinase, protease, and cellulose production on solid media. In addition, chitinolytic and proteolytic activities were estimated at the values of 1.72 ± 0.02UI and 0.49 ± 0.01UI, respectively. However, the mycotoxin evaluation assay revealed that F. culmorum HD15C10 produced zearalenone (ZEA) and the biocontrol agent enhanced its production, but the early inoculation of T. pinophilus, before F. culmorum growth onset, inhibited 100% its growth and, therefore, prevented the presence of ZEA. Hence, this strain can be proposed as a biocontrol agent against F. culmorum, and it can be further investigated for biocontrol of Fusarium root and crown rot in vivo. Full article

Wheat (Triticum aestivum L.) is a crucial global food crop. The intensive crop farming, monoculture cultivation, and impact of climate change affect the susceptibility of wheat cultivars to biotic stresses, mainly caused by soil fungal pathogens, especially those belonging to the genus Fusarium. This situation threatens yield and grain quality through root and crown rot. While conventional chemical fungicides face resistance issues and environmental concerns, biological alternatives like seed priming with natural metabolites are gaining attention. Polyamines, including putrescine, spermidine, and spermine, are attractive priming agents influencing plant development and abiotic stress responses. Spermine in particular shows potential for in vitro antifungal activity against Fusarium. Optimising spermine concentration for seed priming is crucial to maximising protection against Fusarium infection while ensuring robust plant growth. In this research, we explored the potential of the polyamine spermine as a seed treatment to enhance wheat resilience, aiming to identify a sustainable alternative to synthetic fungicides. Our findings revealed that a six-hour seed soak in spermine solutions ranging from 0.5 to 5 mM did not delay germination or seedling growth. In fact, the 5 mM concentration significantly stimulated root weight and length. In complementary in vitro assays, we evaluated the antifungal activity of spermine (0.5–5 mM) against three Fusarium species. The results demonstrated complete inhibition of Fusarium culmorum growth at 5 mM spermine. A less significant effect on Fusarium graminearum and little to no impact on Fusarium oxysporum were found. The performed analysis revealed that the spermine had a fungistatic effect against the pathogen, retarding the mycelium growth of F. culmorum inoculated on the seed surface. A pot experiment with Bulgarian soft wheat cv. Sadovo-1 was carried out to estimate the effect of seed priming with spermine against infection with isolates of pathogenic fungus F. culmorum on plant growth and disease severity. Our results demonstrated that spermine resulted in a reduced distribution of F. culmorum and improved plant performance, as evidenced by the higher fresh weight and height of plants pre-treated with spermine. This research describes the efficacy of spermine seed priming as a novel strategy for managing Fusarium root and crown rot in wheat. Full article

In chili cultivation, obstacles to continuous cropping significantly compromise crop yield and soil health, whereas crop rotation can enhance the microbial environment of the soil and reduce disease incidence. However, its effects on the diversity of rhizosphere soil microbial communities are not clear. In this study, we analyzed the composition and characteristics of rhizosphere soil microbial communities under chili continuous cropping (CC) and chili–cotton crop rotation (CR) using high-throughput sequencing technology. CR treatment reduced the alpha diversity indices (including Chao1, Observed_species, and Shannon index) of bacterial communities and had less of an effect on fungal community diversity. Principal component analysis (PCA) revealed distinct compositional differences in bacterial and fungal communities between the treatments. Compared with CC, CR treatment has altered the structure of the soil microbial community. In terms of bacterial communities, the relative abundance of Firmicutes increased from 12.89% to 17.97%, while the Proteobacteria increased by 6.8%. At the genus level, CR treatment significantly enriched beneficial genera such as RB41 (8.19%), Lactobacillus (4.56%), and Bacillus (1.50%) (p < 0.05). In contrast, the relative abundances of Alternaria and Fusarium in the fungal community decreased by 6.62% and 5.34%, respectively (p < 0.05). Venn diagrams and linear discriminant effect size analysis (LEfSe) further indicated that CR facilitated the enrichment of beneficial bacteria, such as Bacillus, whereas CC favored enrichment of pathogens, such as Firmicutes. Fusarium solani MG6 and F. oxysporum LG2 are the primary chili root-rot pathogens. Optimal growth occurs at 25 °C, pH 6: after 5 days, MG6 colonies reach 6.42 ± 0.04 cm, and LG2 5.33 ± 0.02 cm, peaking in sporulation (p < 0.05). In addition, there are significant differences in the utilization spectra of carbon and nitrogen sources between the two strains of fungi, suggesting their different ecological adaptability. Integrated analyses revealed that CR enhanced soil health and reduced the root rot incidence by optimizing the structure of soil microbial communities, increasing the proportion of beneficial bacteria, and suppressing pathogens, providing a scientific basis for microbial-based soil management strategies in chili cultivation. Full article

Root rot, mainly caused by Fusarium oxysporum, is one of the most destructive diseases and leads to significant economic loss of Astragalus membranaceus. To develop an effective strategy for the management of this serious disease, a bacterial strain 2-12 was screened from A. membranaceus rhizosphere soil and identified as Bacillus paralicheniformis based on the phylogenetic analyses of gyrase subunit B gene (gyrB) and RNA polymerase gene (rpoB) sequences. Interestingly, the volatile organic compounds (VOCs) produced by B. paralicheniformis 2-12 exhibited potent antifungal activities against F. oxysporum, as well as fifteen other plant pathogens. Under scanning electron microscopy observation, hyphae treated with the VOCs exhibited abnormal variation such as distortion, twist, and vesiculation, leading to distinctive protoplasm shrinkage. After treatment with B. paralicheniformis 2-12 VOCs, the lesion diameter and disease incidence both reduced significantly compared to control (p < 0.05), thus demonstrating prominent biological efficiency. Moreover, B. paralicheniformis 2-12 VOCs were composed of 17 VOCs, including 9 alkanes, 3 alcohols, 3 acids and esters, 1 aromatic compound, and 1 alkyne compound. A total of 1945 DEGs, including 1001 up-regulated and 944 down-regulated genes, were screened via transcriptome analysis. These DEGs were mainly associated with membranes and membrane parts, amino acid metabolism, and lipid metabolism. The findings in this work strongly suggested that B. paralicheniformis 2-12 VOCs could be applied as a new candidate for the control of A. membranaceus root rot. Full article

Oregano (Origanum vulgare) cultivation is of great economic importance in Peru. Tacna stands out as its main producer. However, the presence of phytopathogenic fungi represents a challenge for its production. This study aimed to characterize both the morphological and molecular levels of the causal agent of crown and root rot in a crop field in the Camilaca district, Candarave, Tacna. To this end, systematic sampling was carried out using the five-gold method, collecting plants with typical symptoms. Fungi were isolated from diseased roots and characterized using macroscopic and microscopic morphological analysis as well as sequencing and multilocus phylogenetic analysis (ITS, 28S, HIS3, TEF1, TUB2). In addition, pathogenicity tests were performed on healthy plants to confirm the infectivity of the isolates. The results demonstrated that root rot was caused by a complex of phytopathogenic fungi through phylogenetic analysis of Dactylonectria torresensis, Fusarium oxysporum, F. iranicum, and F. redolens. These findings represent the first report of these species as causal agents of oregano root rot in Peru, highlighting the need for integrated management strategies that reduce the economic impact of these diseases and contribute to the sustainability of the crop in key producing regions such as Tacna. Full article

Fusarium root rot, caused by Fusarium equiseti, poses a significant threat to soybean production. This study aimed to explore the genetic basis of resistance to Fusarium equiseti root rot (FERR) by evaluating the resistance phenotype of 346 soybean germplasms and conducting a genome-wide association study (GWAS) using 698,949 SNP markers obtained from soybean germplasm resequencing data. GWAS analysis identified 101 SNPs significantly associated with FERR resistance, distributed across nine chromosomes, with the highest number of SNPs on chromosomes 13 and 20. Further gene-based association and allele variation analyses identified candidate genes whose mutations are closely related to FERR resistance. To accelerate soybean FERR resistance breeding screening, we developed CAPS markers S13_14464319-CAPS1 and S15_9215524-CAPS2, targeting these SNP sites, and KASP markers based on the S15_9205620-G/A, providing an effective tool for marker-assisted selection (MAS). This study offers a valuable theoretical foundation and molecular marker resources for the functional validation of FERR resistance genes and soybean disease resistance breeding. Full article

The cultivation of cowpea (Vigna unguiculata), a vital vegetable crop, faces significant threats from Fusarium spp.-induced root rot. In this study, three fungal pathogens (Fusarium falciforme HKFf, Fusarium incarnatum HKFi, and Fusarium oxysporum HKFo) were isolated from symptomatic cowpea plants, and we screened 90 rhizobacteria from healthy rhizospheres using six culture media. Among these pathogens, Priestia megaterium TSA-10E showed a notable suppression of F. oxysporum HKFo (63.21%), F. incarnatum HKFi (55.16%), and F. falciforme HKFf (50.93%). In addition, Bacillus cereus KB-6 inhibited the mycelial growth of F. incarnatum HKFi and F. oxysporum HKFo by 42.39% and 47.93%, respectively. Critically, cell-free filtrates from P. megaterium TSA-10E and B. cereus KB-6 cultures reduced conidial germination in F. oxysporum HKFo and F. incarnatum HKFi, highlighting their role in disrupting the early infection stages. In greenhouse trials, TSA-10E and KB-6 reduced disease severity by 48.7% and 40.4%, respectively, with treated plants maintaining healthy growth while untreated controls succumbed to wilting. Broad-spectrum assays revealed that B. subtilis TSA-6E and P. megaterium TSA-10E were potent antagonists against both economic and grain crop pathogens. These findings underscore the potential of rhizobacteria as sustainable biocontrol agents for managing root rot disease caused by Fusarium spp. in cowpea cultivation. Full article

Root rot is one of the most serious diseases affecting Astragalus membranaceus, significantly reducing its yield and quality. This study focused on root rot in Astragalus membranaceus var. mongholicus. Pathogenic fungi were isolated and identified. The pathogenicity of seven strains of pathogenic fungi was verified according to Koch’s postulates. The inhibitory effects of eight classic fungicides and nine strains of biocontrol agents on the pathogenic fungi were determined using the mycelial growth rate method. Through morphological and ITS phylogenetic analyses, strains CDF5, CDF6, and CDF7 were identified as Fusarium oxysporum, while strains CDF1, CDF2, CDF3, and CDF4 were identified as Fusarium solani. Indoor virulence tests showed that, among the eight tested fungicides, carbendazim exhibited the strongest inhibitory effect on the mycelial growth of both F. oxysporum and F. solani, with a half-maximal effective concentration (EC₅₀) value of (0.44 ± 0.24) mg/mL, making it a highly promising chemical agent for the control of A. membranaceus var. mongholicus root rot. Among the nine biocontrol agents, KRS006 showed the best inhibitory effect against the seven pathogenic strains, with an inhibition rate ranging from 42.57% to 55.51%, and it can be considered a candidate strain for biological control. This study identified the biocontrol strain KRS006 and the chemical fungicide carbendazim as promising core agents for the biological and chemical control of A. membranaceus var. mongholicus root rot, respectively, providing a theoretical foundation for establishing a dual biocontrol–chemical control strategy. Based on the excellent performance of the biocontrol bacteria and fungicides in the pathogen control tests, future research should focus on field trials to verify the synergistic effect of this integrated control strategy and clarify the interaction mechanism between the antibacterial metabolites produced by the biocontrol bacteria KRS006 and carbendazim. Additionally, continuous monitoring of the evolution of Fusarium spp. resistance to carbendazim is critical to ensure the long-term sustainability of the integrated control system. Full article

Wheat (Triticum aestivum L.) is a major cereal crop globally, but its production is increasingly threatened by fungal pathogens, particularly Fusarium culmorum (Wm. G. Sm.) Sacc., which causes seedling blight and root rot, leading to yield losses and mycotoxin contamination. Conventional control strategies, such as crop rotation and the use of fungicides, are often inadequate and contribute to the development of resistance, particularly with the overuse of similar modes of action. This study investigated quaternary pyridinium salts—nicotinamide and isonicotinamide derivatives—as potential sustainable antifungal agents. In vivo tests involved treating sterilized wheat seeds grown in sterile sand that had been inoculated with F. culmorum, using compounds previously confirmed to be active in vitro. Disease index, shoot and root length, and fresh and dry biomass were measured. Among the tested compounds, nicotinamide derivatives (2) and (3) showed the lowest disease index (0.9) at a concentration of 10 µg/mL. Most compounds promoted plant and root growth. Isonicotinamide derivatives (6) and (7) at 100 µg/mL increased root dry weight, while compound (6) at 10 µg/mL resulted in the most significant increase in plant length. These findings highlight the dual antifungal and growth-promoting potential of certain eco-friendly derivatives for managing F. culmorum and supporting wheat seedling development. Full article

Soilborne diseases cause losses of 45–70% in faba bean in Ethiopia. Studies were undertaken to define soilborne pathogens and their complexes in Ethiopia. First, the severity of root rot was assessed in 150 field sites across seven Ethiopian regions. Soil samples were collected, and the DNA of 29 pests and pathogens was quantified using a commercial quantitative PCR (qPCR) soil testing service. There was a very high incidence rate of Macrophomina phaseolina, as well as Pythium clades F and I. The other detected species in order of incidence included Fusarium redolens, Rhizoctonia solani, Aphanomyces euteiches, Phytophthora megasperma, Sclerotinia sclerotiorum and S. minor, and Verticillium dahliae, as well as low levels of Thielaviopsis basicola. Five anastomosis groups (AG) of R. solani, namely AG2.1, AG2.2, AG3, AG4, and AG5, were detected, of which AG2.2 and AG4 were most prevalent. We believe this is the first report of occurrence for Ethiopia of A. euteiches, Ph. megasperma, T. basicola, and the five AGs for R. solani. There were very high incidence rates of the foliar pathogens Botrytis cinerea, B. fabae, Didymella pinodes, and Phoma pinodella and of the nematode Pratylenchus thornei, followed by P. neglectus and P. penetrans. The root rot severity and distribution varied significantly across regions, as well as with soil types, soil pH, and soil drainage. Subsequently, metabarcoding of the soil DNA was undertaken using three primer pairs targeting fungi (ITS2), Fusarium species (TEF1 α), and Oomycetes (ITS1Oo). The ITS2 and TEF1α primers emphasized F. oxysporum as the most abundant soilborne fungal pathogen and highlighted F. ananatum, F. brachygibbosum, F. brevicaudatum, F. clavum, F. flagelliforme, F. keratoplasticum, F. napiforme, F. nelsonii, F. neocosmosporiellum, F. torulosum, and F. vanettenii as first reports of occurrence for Ethiopia. The ITS1Oo primer confirmed Pythium spp. as the most prevalent of all Oomycetes. Full article

Common buckthorn (Rhamnus cathartica L.) is a small tree that forms dense stands, displacing native plant species and threatening natural forest habitats in its introduced range in North America. Removal via cutting is labor intensive and often ineffective due to vigorous resprouting. Although chemical control methods are effective, they can negatively affect sensitive ecosystems. A mycoherbicide that selectively kills buckthorn would provide an additional method for control. In the present study, fungi were collected from dying buckthorn species (Frangula alnus Mill., Rhamnus cathartica, Ventia alnifolia L’Hér) located at 19 sites across Minnesota and Wisconsin for their potential use as mycoherbicides for common buckthorn. A total of 412 fungi were isolated from samples of diseased tissue and identified via DNA extraction and sequencing. These fungi were identified as 120 unique taxa belonging to 81 genera. Of these fungi, 46 species belonging to 26 genera were considered to be canker or root-rot pathogens of woody plants, including species in Cytospora, Diaporthe, Diplodia, Dothiorella, Eutypella, Fusarium, Hymenochaete, Irpex, Phaeoacemonium, and others. A future study testing the pathogenicity of these putative pathogens of buckthorn is now needed to assess their utility as potential mycoherbicide agents for control of common buckthorn. Full article

Root rot, a globally devastating disease of common bean (Phaseolus vulgaris L.), remains a major constraint on bean production across China. Despite its agricultural impact, the pathogen complex associated with this disease has been poorly characterized in most provinces. To address this critical knowledge gap, we conducted nationwide surveys during 2016–2018, systematically sampling 1–10 symptomatic plants from each of 121 (2016) and 170 (2018) field sites across 17 provinces in China’s major vegetable production regions. Isolates obtained from symptomatic root tissues underwent morphological screening, followed by molecular identification using partial sequences of EF1-α for Fusarium species and ITS regions for other genera. Pathogenicity of representative isolates was subsequently confirmed through controlled greenhouse assays. This integrated approach revealed fourteen fungal and oomycete genera, with Fusarium (predominantly F. oxysporum and F. solani) and Rhizoctonia (R. solani) emerging as the most prevalent pathogens. Notably, pathogen composition exhibited significant regional variation and underwent temporal shifts across developmental stages. Additionally, F. oxysporum, F. solani, and R. solani demonstrated significant interspecies associations with frequent co-occurrence in bean root rot systems. Collectively, this first comprehensive characterization of China’s common bean root rot complex not only clarifies spatial–temporal pathogen dynamics but also provides actionable insights for developing region- and growth stage-specific management strategies, particularly through targeted control of dominant pathogens during key infection windows. Full article

Potato early dying disease complex (PED) leads to premature senescence and rapid decline in potato plants. Unlike potato wilt caused solely by Verticillium species, PED symptoms are more severe due to the synergistic effects of multiple pathogens, including root-lesion nematodes, fungi such as Colletotrichum and Fusarium, and soft-rot bacteria. To investigate the microbiome responsible for PED, soil and stem samples from healthy-looking and symptomatic plants were analyzed using amplicon-targeted next-generation sequencing (Illumina MiSeq and PacBio technologies). Samples were collected from four locations in New Brunswick, Canada from fields previously rotated with barley or oat. Comparative analysis of the bacterial, fungal, and eukaryotic diversity in soil samples showed minimal differences, with only bacterial alpha diversity influenced by the plant health status. Verticillium dahliae was abundant in all soil samples, and its abundance was significantly higher in the stems of diseased plants. Additional fungal species implicated in PED, including Plectosphaerella cucumerina, Colletotrichum coccodes, Botrytis sp., and Alternaria alternata, were also identified in the stems. This study highlights the complex, plant-associated microbial interactions underlying PED and provides a foundation for microbiome-informed disease management strategies. Full article