Adaptation of Fusarium Head Blight Pathogens to Changes in Agricultural Practices and Human Migration.

Fusarium head blight (FHB) is one of the most destructive wheat diseases worldwide. To understand the impact of human migration and changes in agricultural practices on crop pathogens, here population genomic analysis with 245 representative strains from a collection of 4,427 field isolates of Fusarium asiaticum, the causal agent of FHB in Southern China is conducted. Three populations with distinct evolution trajectories are identifies over the last 10,000 years that can be correlated with historically documented changes in agricultural practices due to human migration caused by the Southern Expeditions during the Jin Dynasty. The gradual decrease of 3ADON-producing isolates from north to south along with the population structure and spore dispersal patterns shows the long-distance (>250 km) dispersal of F. asiaticum. These insights into population dynamics and evolutionary history of FHB pathogens are corroborated by a genome-wide analysis with strains originating from Japan, South America, and the USA, confirming the adaptation of FHB pathogens to cropping systems and human migration.

Population genomics of Fusarium graminearum isolates from the Americas.

Fusarium head blight (FHB) is a major disease of wheat and barley worldwide and is caused by different species in the genus Fusarium, Fusarium graminearum being the most important. We conducted population genomics analyses using SNPs obtained through genotyping by sequencing of over 500 isolates of F. graminearum from the US Upper Midwest, New York, Louisiana, and Uruguay. PCA and STRUCTURE analyses group our isolates into four previously described populations: NA1, NA2, Southern Louisiana (SLA) and Gulf Coast (GC). Some isolates were not assigned to populations because of mixed ancestry. Population structure was associated with toxin genotype and geographic origin. The NA1, NA2, and SLA populations are differentiated (FST 0.385 - 0.551) but the presence of admixed isolates indicates that the populations are not reproductively isolated. Patterns of linkage disequilibrium (LD) decay suggest frequent recombination within populations. Fusarium graminearum populations from the US have great evolutionary potential given the high recombination rate and a large proportion of admixed isolates. The NA1, NA2, and Southern Louisiana (SLA) populations separated from their common ancestral population roughly at the same time in the past and are evolving with moderate levels of subsequent gene flow between them. Genome-wide selection scans in all three populations revealed outlier regions with the strongest signatures of recent positive natural selection. These outlier regions include many genes with unknown function and some genes with known roles in plant-microbe interaction, fungicide/drug resistance, cellular transport and genes that are related to cellular organelles. Only a very small proportion of outlier regions are shared as outliers among the three populations, suggesting unique host-pathogen interactions and environmental adaptation.

Analyzing the defense response mechanism of Atractylodes macrocephala to Fusarium oxysporum through small RNA and degradome sequencing.

Introduction: Fusarium oxysporum is a significant soil-borne fungal pathogen that affects over 100 plant species, including crucial crops like tomatoes, bananas, cotton, cucumbers, and watermelons, leading to wilting, yellowing, growth inhibition, and ultimately plant death. The root rot disease of A. macrocephala, caused by F. oxysporum, is one of the most serious diseases in continuous cropping, which seriously affects its sustainable development. Methods: In this study, we explored the interaction between A. macrocephala and F. oxysporum through integrated small RNA (sRNA) and degradome sequencing to uncover the microRNA (miRNA)-mediated defense mechanisms. Results: We identified colonization of F. oxysporum in A. macrocephala roots on day 6. Nine sRNA samples were sequenced to examine the dynamic changes in miRNA expression in A. macrocephala infected by F. oxysporum at 0, 6, and 12 days after inoculation. Furthermore, we using degradome sequencing and quantitative real-time PCR (qRT-PCR), validated four miRNA/target regulatory units involved in A. macrocephala-F. oxysporum interactions. Discussion: This study provides new insights into the molecular mechanisms underlying A. macrocephala's early defense against F. oxysporum infection, suggesting directions for enhancing resistance against this pathogen.

Phytotoxic Isocassadiene-Type Diterpenoids from Tomato Fusarium Crown and Root Rot Pathogen Fusarium oxysporum f. sp. radicis-lycopersici.

Fusarium crown and root rot (FCRR) has emerged as a highly destructive soil-borne disease, posing a significant threat to the safe cultivation of tomatoes in recent years. The pathogen of tomato FCRR is Fusarium oxysporum f. sp. radicis-lycopersici (Forl). To explore potential phytotoxins from Forl, eight undescribed diterpenoids namely fusariumic acids A-H (1-8) were isolated. Their structures were elucidated by using spectroscopic data analyses, quantum chemical calculations, and X-ray crystallography. Fusariumic acids A (1) and C-H (3-8) were typical isocassadiene-type diterpenoids, while fusariumic acid B (2) contained a cage-like structure with an unusual 7,8-seco-isocassadiene skeleton. A biosynthetic pathway of 2 was proposed. Fusariumic acids A (1) and C-H (3-8) were further assessed for their phytotoxic effects on tomato seedlings at 200 µg/mL. Among them, fusariumic acid F (6) exhibited the strongest inhibition against the hypocotyl and root elongation of tomato seedlings, with inhibitory rates of 61.3 and 45.3%, respectively.

Fusarium graminearum effector FgEC1 targets wheat TaGF14b protein to suppress TaRBOHD-mediated ROS production and promote infection.

Fusarium head blight (FHB), caused by Fusarium graminearum, is a devastating disease of wheat globally. However, the molecular mechanisms underlying the interactions between F. graminearum and wheat remain unclear. Here, we identified a secreted effector protein, FgEC1, that is induced during wheat infection and is required for F. graminearum virulence. FgEC1 suppressed flg22- and chitin-induced callose deposition and reactive oxygen species (ROS) burst in Nicotiana benthamiana. FgEC1 directly interacts with TaGF14b, which is upregulated in wheat heads during F. graminearum infection. Overexpression of TaGF14b increases FHB resistance in wheat without compromising yield. TaGF14b interacts with NADPH oxidase respiratory burst oxidase homolog D (TaRBOHD) and protects it against degradation by the 26S proteasome. FgEC1 inhibited the interaction of TaGF14b with TaRBOHD and promoted TaRBOHD degradation, thereby reducing TaRBOHD-mediated ROS production. Our findings reveal a novel pathogenic mechanism in which a fungal pathogen acts via an effector to reduce TaRBOHD-mediated ROS production.

Enhancing tomato plant immune responses to Fusarium wilt disease by red seaweed Jania sp.

The novelty of this study lies in demonstrating a new approach to control wilt diseases using Jania ethyl acetate extract. In the current investigation, the potential impacts of Jania sp. ethyl acetate extract (JE) on Tomato Fusarium oxysporum wilt (FOW) have been studied. The in vitro antifungal potential of JE against F. oxysporum (FO) was examined. GC-MS investigation of the JE revealed that, the compounds possessing fungicidal action were Phenol,2-methoxy-4-(2-propenyl)-,acetate, Eugenol, Caryophyllene oxide, Isoespintanol, Cadinene, Caryophylla-4(12),8(13)-dien-5à-ol and Copaen. Jania sp. ethyl acetate extract exhibited strong antifungal potential against FO, achieving a 20 mmzone of inhibition. In the experiment, two different methods were applied: soil irrigation (SI) and foliar application (FS) of JE. The results showed that both treatments reduced disease index present DIP by 20.83% and 33.33% respectively. The findings indicated that during FOW, proline, phenolics, and the antioxidant enzymes activity increased, while growth and photosynthetic pigments decreased. The morphological features, photosynthetic pigments, total phenol content, and antioxidant enzyme activity of infected plants improved when JE was applied through soil or foliar methods. It is interesting to note that the application of JE had a substantially less negative effect on the isozymes peroxidase and polyphenol oxidase in tomato plants, compared to FOW. These reactions differed depending on whether JE was applied foliarly or via the soil. Finally, the use of Jania sp. could be utilized commercially as an ecologically acceptable method to protect tomato plants against FOW.

Cytochrome c Oxidase Influences Pyraclostrobin Sensitivity in Fusarium graminearum by Regulating FgAox Through Transcription Factors FgAod2 and FgAod5.

Cytochrome c oxidase (Cox) is a crucial terminal oxidase in the electron transport chain. In this study, we generated 14 Cox gene deletion or overexpression mutants in Fusarium graminearum. Fungicide sensitivity tests revealed that 11 Cox gene deletion mutants displayed resistance to pyraclostrobin, while 10 overexpression mutants showed hypersensitivity. RNA-Seq and RT-qPCR analyses demonstrated the upregulation of FgAox (alternative oxidase in F. graminearum), FgAod2, and FgAod5 (alternative oxidase deficiency in F. graminearum) in ΔFgCox4-2 and ΔFgCox17-75 mutants. In 11 Cox gene deletion mutants, FgAox expression was significantly upregulated, whereas in 10 Cox gene overexpression mutants, it was significantly downregulated. FgAox overexpression mutants exhibit resistance to pyraclostrobin, while FgAox deletion mutants show hypersensitivity to pyraclostrobin. FgAod2 and FgAod5 were identified as transcription factors for FgAox. Our findings reveal that FgCox influences pyraclostrobin sensitivity by regulating FgAox through FgAod2 and FgAod5. Understanding pyraclostrobin resistance mechanisms in F. graminearum could help develop better fungicide rotation and application strategies to manage resistance and guide the creation of new fungicides targeting different pathways.

First Report of Fusarium kyushuense Causing Leaf Spot on Sweet Persimmon in China.

Sweet persimmon (Diospyros kaki L.) is a fruit of significant nutritional and commercial value in Asia. In summer 2023, leaf spots were observed affecting 20 to 30% of sweet persimmon trees in a commercial orchard located in Gongcheng City, Guangxi, China. Initially, the infected leaves exhibited sparse light brown spots on their upper surface, which subsequently evolved into brown circular to irregular lesions encircled by a yellow halo. Eventually, these lesions became densely distributed across the leaves leading to insufficient nutrient accumulation in the fruit. To isolate the pathogen, diseased leaves were cut into small pieces (5×5 mm), disinfected with 75% ethanol for 15 seconds, followed by 1% NaClO for 1minute, rinsed three times with sterile water, and then transferred onto potato dextrose agar (PDA) plates. The plates were then incubated in darkness for 3 days at 25°C. Pure cultures were obtained using the hyphal-tip method and single-spore isolation. On PDA, the colonies initially appeared fluffy and white after 24 hours, turning yellowish or red after 3 days. Macroconidia (average length of 26.1 µm in length × 4.3 µm in width, n = 50) exhibited dorsiventral curvature and were hyaline, with 3 to 5 septa. Microconidia (average length of 9.45 µm in length × 3.4 µm in width, n = 50) were hyaline, aseptate, and oval. Two representative isolates, Gxfky1 and Gxfky2, were selected for further molecular analyses. Their internal transcribed spacer (ITS) region rDNA gene were amplified via PCR and sanger sequenced (GenBank Accession Nos. PP506475, PP506593) using the primer pair ITS1/ITS4 (White et al. 1990), showing more than 99% sequence identity with Fusarium kyushuense type-material strain NRRL3509 (NR_152943) according to BLASTn analysis in NCBI. To further confirm the identity of the isolates, four gene sequences were amplified: RPB1 (PP532864, PP532865), RPB2 (PP532866, PP532867), TEF1 (PP580505, PP580506), and TUB2 (PP532862, PP532863), using the F5/G2R, 5f2/11ar, EF1/EF2, and T1/T2 primer sets, respectively (O'Donnell et al., 1997; O'Donnell et al., 2010). A multi-locus maximum likelihood phylogenetic analysis revealed that Gxfky1 and Gxfky2 clustered with strains F. kyushuense with 100% bootstrap support. Pathogenicity tests using Gxfky1 and Gxfky2 were conducted on leaves of two-year-old sweet persimmon plants using non-wound inoculation. Specifically, 5-mm mycelial plugs and sterile agar plugs were placed on six leaves and secured with cling film, with six plugs each for the inoculation treatment and negative control, respectively. They were then incubated in a greenhouse at room temperature (25 ± 2°C) with a relative humidity of 70 to 80%. After 5 days, the same symptoms on naturally infected plants were observed on leaves inoculated with mycelium, while no symptoms were observed on the controls. The same fungus were reisolated from the inoculated leaves and identified based on morphology and the TEF1 gene sequence, thus fulfilling Koch's postulates. Fusarium kyushuense has previously been reported to cause diseases in various plant species, including maize (Cao et al., 2021), rice (Wang et al., 2024), and tobacco (Wang et al., 2013). To our knowledge, this is the first report of F. kyushuense causing leaf spot on sweet persimmon in China, which expands the known host range of this pathogen.

Spray-induced gene silencing (SIGS) as a tool for the management of Pine Pitch Canker forest disease.

Global change is exacerbating the prevalence of plant diseases caused by pathogenic fungi in forests worldwide. The conventional use of chemical fungicides, which is commonplace in agricultural settings, is not sanctioned for application in forest ecosystems, so novel control strategies are imperative. SIGS (Spray-Induced Gene Silencing) is a promising approach that can modulate the expression of target genes in eukaryotes in response to double-stranded RNA (dsRNA) present in the environment that triggers the RNA interference (RNAi) mechanism. SIGS exhibited notable success in reducing virulence when deployed against some crop fungal pathogens, such as Fusarium graminearum, Botrytis cinerea and Sclerotinia sclerotiorum, among others. However, there is a conspicuous dearth of studies evaluating the applicability of SIGS for managing forest pathogens. This research aimed to determine whether SIGS could be used to control Fusarium circinatum, a widely impactful forest pathogen that causes Pine Pitch Canker disease. Through a bacterial synthesis, we produced dsRNA molecules to target fungal essential genes involved to vesicle trafficking (Vps51, DCTN1, and SAC1), signal transduction (Pp2a, Sit4, Ppg1, and Tap42), and cell wall biogenesis (Chs1, Chs2, Chs3b, Gls1) metabolic pathways. We confirmed that F. circinatum is able to uptake externally applied dsRNA, triggering an inhibition of the pathogen's virulence. Furthermore, this study pioneers the demonstration that recurrent applications of dsRNAs in SIGS are more effective in protecting plants than single applications. Therefore, SIGS emerges as an effective and sustainable approach for managing plant pathogens, showcasing its efficacy in controlling a globally significant forest pathogen subject to quarantine measures.

Mycotoxins and coccidiosis in poultry - co-occurrence, interaction, and effects.

Avian coccidiosis, a common disease caused by Eimeria species, results in significant losses in global poultry production. Mycotoxins are low-molecular-weight natural products (i.e., small molecules) produced as secondary metabolites by filamentous fungi and they have the potential to economically and significantly affect global poultry production. Little is known about the relationship between mycotoxins and avian coccidiosis, although they often co-occur in the field. This comprehensive review examines the intricate relationship between mycotoxins and avian coccidiosis, in particular how mycotoxins, including aflatoxins, ochratoxins, trichothecenes as well as Fusarium mycotoxins, compromise the health of the poultry flock and open the door to Eimeria parasites in the gut. In addition, this review sheds light on the immunosuppressive effects of mycotoxins, their disruption of cellular signaling pathways, and the consequent exacerbation of coccidiosis infections. The mechanisms of mycotoxin toxicity are also reviewed, emphasizing direct damage to intestinal epithelial cells, impaired nutrient absorption, inflammation, oxidative stress, and changes in the gut microbiota. Finally, the consequences for the prevention and treatment of coccidiosis when mycotoxins are present in the feed are discussed. This review emphasizes the need for effective management strategies to mitigate the combined risks of mycotoxins and coccidiosis and highlights the complexity of diagnosing and controlling these interrelated problems in poultry. The review advocates a holistic approach that includes strict feed management, disease prevention measures and regular monitoring to maintain the health and productivity of poultry against these significant challenges.

A ribonuclease T2 protein FocRnt2 contributes to the virulence of Fusarium oxysporum f. sp. cubense tropical race 4.

Banana Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4), is a major disease of banana plants worldwide. Effector proteins play critical roles in banana-Foc TR4 interaction. Our previous studies highlighted a ribonuclease protein belonging to the T2 family (named as FocRnt2) in the Foc TR4 secretome, which was predicted to be an effector. However, its biological function in Foc TR4 infection is still unclear. Herein, we observed significant expression of FocRnt2 during the early stage of fungal infection in planta. A yeast signal sequence trap assay showed that FocRnt2 contained a functional signal peptide for secretion. FocRnt2 possessed ribonuclease activity that could degrade the banana total RNA in vitro. Subcellular localization showed that FocRnt2 was localized in the nucleus and cytoplasm of Nicotiana benthamiana leaves. Transient expression of FocRnt2 suppressed the expression of salicylic acid- and jasmonic acid-signalling marker genes, reactive oxygen species accumulation, and BAX-mediated cell death in N. benthamiana. FocRnt2 deletion limited fungal penetration, reduced fusaric acid biosynthesis in Foc TR4, and attenuated fungal virulence against banana plants, but had little effect on Foc TR4 growth and sensitivity to various stresses. Furthermore, FocRnt2 deletion mutants induced higher expression of the defence-related genes in banana plants. These results suggest that FocRnt2 plays an important role in full virulence of Foc TR4, further improving our understanding of effector-mediated Foc TR4 pathogenesis.

Genome-wide search and gene expression studies reveal candidate effectors with a role in pathogenicity and virulence in Fusarium graminearum.

Fusarium graminearum causes Fusarium head blight (FHB) disease in wheat worldwide. Although F. graminearum is reported to secrete several effectors, their role in virulence and pathogenicity is unknown. The study aimed at identifying candidate genes with a role in pathogenicity and virulence using two different host systems, Arabidopsis thaliana and wheat, challenged with F. graminearum TN01. Detached leaf assay and histological studies revealed the virulent nature of TN01. A genome-wide in silico search revealed several candidate genes, of which 23 genes were selected based on reproducibility. Gene expression studies by reverse transcriptase-polymerase chain reaction (RT-PCR) in leaf tissues of Arabidopsis and the two wheat genotypes, the susceptible (Sonalika) and the resistant (Nobeoka Bozu/Nobeoka), compared with mock-treated controls in a time-course study using fungal- and plant-specific genes as internal controls revealed that these genes were differentially regulated. Further, expression of these candidates in F. graminearum-inoculated Sonalika and Nobeoka spikes compared with mock-treated controls revealed their role in pathogenicity and virulence. Gene ontology studies revealed that some of these secretory proteins possessed a role in apoptosis and ceratoplatanin and KP4 killer toxin syntheses. A three-dimensional protein configuration was performed by homology modeling using trRosetta. Further, real-time quantitative PCR (RT-qPCR) studies in F. graminearum-inoculated Arabidopsis and wheat at early time points of inoculation revealed an increased expression of the majority of these genes in Sonalika, suggesting their possible role in pathogenicity, whereas low mRNA abundance was observed for 11 of these genes in the resistant genotype, Nobeoka, compared with Sonalika, indicating their role in virulence of F. graminearum.

Impact of IPM practices on microbial population and disease development in transplanted and direct-seeded rice.

Integrated pest management (IPM) is a comprehensive approach to managing diseases, focusing on combining various strategies to reduce pathogen populations effectively and in an environmentally conscious way. We investigated the effects of IPM on beneficial microbial populations and its relationship with pathogen populations in both direct-seeded rice (DSR) and transplanted rice (TR) systems. This study demonstrates that IPM practices have significantly higher populations of beneficial microbes, such as Trichoderma harzianum and Pseudomonas fluorescens, and lower level of the pathogen Fusarium verticillioides compared to non-IPM (farmer practices). The average mean population of T. harzianum was 6.38 × 103 CFU/g in IPM compared to 3.22 × 103 CFU/g in non-IPM during 2019 in TR at Bambawad. P. fluorescens mean population in 2019 was significantly higher in IPM (4.67 × 103 CFU/g) than in non-IPM (3.82 × 103 CFU/g) at the Karnal location in DSR. The F. verticillioides populations were significantly lower in IPM fields (9.46 × 103 CFU/g) compared to non-IPM fields (11.48 × 103 CFU/g) during 2017 at Haridwar in TR. Over three years, a significant increase in the populations of beneficial microbes in IPM plots was observed in all three locations of both TR and DSR, highlighting the sustainable impact of IPM practices. Disease dynamics analysis revealed that IPM effectively managed key diseases in both DSR and TR systems, with significant correlations between microbial density and disease severity. A significant positive correlation was recorded between F. verticillioides population and bakanae incidence at all three locations. Sheath blight incidence was negatively correlated with P. fluorescens population in both TR and DSR. In DSR, bacterial blight and brown spot diseases are reduced with the increased population of T. harzianum. Bioagents T. harzianum and P. fluorescens reduced disease incidence, underscoring the role of beneficial microbes in disease suppression and their importance for sustainable production using IPM practices.

Analysis of Ginkgo biloba Root Exudates and Inhibition of Soil Fungi by Flavonoids and Terpene Lactones.

Ginkgo biloba is abundant in secondary metabolites, including flavonoids and terpenoids. While the majority of research has focused on the role of these compounds in disease resistance, their specific contribution to pathogen defense has been rarely explored. In this study, we collected root exudates from hydroponically cultivated ginkgo seedlings and conducted a metabolomic analysis. We identified several primary metabolites mainly comprising amino acids and nucleotides, while secondary metabolites consisted of various compounds, including bioactive compounds such as flavonoids and terpenoids. Focusing on the secondary metabolites with relatively higher abundance in the exudates, we selected a mixture of flavonoids and terpenoids for in vitro inhibition experiments against two soil-borne fungal pathogens, Fusarium oxysporum f. sp. cucumerinum that causes cucumber wilt and Rhizoctonia solani AG-8 that causes wheat root rot. The results indicated that the growth rate of both fungus cells was significantly reduced with the increasing concentration of the flavonoid and terpenoid mixture extracted from ginkgo and was completely inhibited at a concentration of 5 mg/mL. Further experiments revealed that this mixture of flavonoids and terpenoids had a destructive effect on the cellular structure of both fungi, thereby reducing cell viability and achieving an antifungal effect. These findings provide a foundation for further research into the use of ginkgo extracts in biological control.

Fusarium Wilt of Coriander: Root Cause Analysis and Varietal Tolerance Development.

Since 2012, growers of coriander, Coriandrum sativum L., in Israel have been suffering from summer wilting that can result in entire fields collapsing. The current study aimed to determine the cause of the phenomenon and find a genetic solution to the problem. The disease was reproduced in a growth chamber using naturally-infested soil from a commercial field. Wilt became apparent within two weeks, and after ten weeks, all plants died compared to plants in sterilized soil from the same source. Fusarium oxysporum was isolated from infected plants, and Koch's postulates were completed. Sequence analysis of the Elongation Factor (EF1α) encoding gene of the pathogen had a 99.54% match to F. oxysporum f. sp. coriandrii. Several coriander varieties were screened for resistance or tolerance to the disease. In four independent experiments, only the cultivar 'Smadi' showed high tolerance, while other genotypes were susceptible. In a trial in a naturally infested field, the cultivar 'Smadi' outperformed the commercial cultivar 'Blair'. 'Smadi' provides a cropping solution to many Israeli farmers, yet this winter cultivar bolts early in the summer. There is a further need to characterize the tolerance mechanism and inheritance for informed breeding of late-bolting Fusarium-resistant coriander.

Chitinase Gene FoChi20 in Fusarium oxysporum Reduces Its Pathogenicity and Improves Disease Resistance in Cotton.

Chitinase genes, as a class of cell wall hydrolases, are essential for the development and pathogenesis of Fusarium oxysporum f.sp. vasinfectum (F. ox) in cotton, but related research focused on chitinase genes are limited. This study explored two island cotton root secretions from the highly resistant cultivar Xinhai 41 and sensitive cultivar Xinhai 14 to investigate their interaction with F. ox by a weighted correlation network analysis (WGCNA). As a result, two modules that related to the fungal pathogenicity emerged. Additionally, a total of twenty-five chitinase genes were identified. Finally, host-induced gene silencing (HIGS) of FoChi20 was conducted, and the cotton plants showed noticeably milder disease with a significantly lower disease index than the control. This study illuminated that chitinase genes play crucial roles in the pathogenicity of cotton wilt fungi, and the FoChi20 gene could participate in the pathogenesis of F. ox and host-pathogen interactions, which establishes a theoretical framework for disease control in Sea Island cotton.

Fusarium mycotoxins: The major food contaminants.

Mycotoxins, which are secondary metabolites produced by toxicogenic fungi, are natural food toxins that cause acute and chronic adverse reactions in humans and animals. The genus Fusarium is one of three major genera of mycotoxin-producing fungi. Trichothecenes, fumonisins, and zearalenone are the major Fusarium mycotoxins that occur worldwide. Fusarium mycotoxins have the potential to infiltrate the human food chain via contamination during crop production and food processing, eventually threatening human health. The occurrence and development of Fusarium mycotoxin contamination will change with climate change, especially with variations in temperature, precipitation, and carbon dioxide concentration. To address these challenges, researchers have built a series of effective models to forecast the occurrence of Fusarium mycotoxins and provide guidance for crop production. Fusarium mycotoxins frequently exist in food products at extremely low levels, thus necessitating the development of highly sensitive and reliable detection techniques. Numerous successful detection methods have been developed to meet the requirements of various situations, and an increasing number of methods are moving toward high-throughput features. Although Fusarium mycotoxins cannot be completely eliminated, numerous agronomic, chemical, physical, and biological methods can lower Fusarium mycotoxin contamination to safe levels during the preharvest and postharvest stages. These theoretical innovations and technological advances have the potential to facilitate the development of comprehensive strategies for effectively managing Fusarium mycotoxin contamination in the future.

Development and application of multiplex PCR for the rapid identification of four Fusarium spp. associated with Fusarium crown rot in wheat.

Fusarium crown rot (FCR), caused by Fusarium spp., is a devastating disease in wheat growing areas. Previous studies have shown that FCR is caused by co-infection of F. graminearum, F. pseudograminearum, F. proliferatum and F. verticillioides in Hubei Province, China. In this study, a method was developed to simultaneously detected DNAs of F. graminearum, F. pseudograminearum, F. proliferatum and F. verticillioides that can efficiently differentiate them. Whole genome sequence comparison of these four Fusarium spp. was performed and a 20 bp sequence was designed as an universal upstream primer. Specific downstream primers of each pathogen was also designed, which resulted in a 206, 482, 680, and 963 bp amplicon for each pathogen, respectively. Multiplex PCR specifically identified F. graminearum, F. pseudograminearum, F. proliferatum and F. verticillioides but not from other 46 pathogens, and the detection limit of target pathogens is about 100 pg/µl. Moreover, we accurately determined the FCR pathogen species in wheat samples using the optimized multiplex PCR method. These results demonstrate that the multiplex PCR method established in this study can efficiently and rapidly identify F. graminearum, F. pseudograminearum, F. proliferatum, and F. verticillioides, which should provide technical support for timely and targeted prevention and control of FCR.

Isolation and characterization of native antagonistic rhizobacteria against Fusarium wilt of chilli to promote plant growth.

In the eastern coastal regions of Odisha, wilt caused by Fusarium oxysporum f. sp.capsici is an extremely damaging disease in chilli. This disease is very difficult to manage with chemical fungicides since it is soil-borne in nature. The natural rhizosphere soil of the chilli plant was used to isolate and test bacterial antagonists for their effectiveness and ability to promote plant growth. Out of the fifty-five isolates isolated from the rhizosphere of healthy chilli plants, five isolates, namely Iso 01, Iso 17, Iso 23, Iso 24, and Iso 32, showed their highly antagonistic activity against F. oxysporum f. sp. capsici under in vitro. In a dual culture, Iso 32 (73.3%) and Iso 24 (71.5%) caused the highest level of pathogen inhibition. In greenhouse trials, artificially inoculated chilli plants treated with Iso 32 (8.8%) and Iso 24 (10.2%) had decreased percent disease incidence (PDI), with percent disease reduction over control of 85.6% and 83.3%, respectively. Iso 32 and Iso 24 treated chilli seeds have shown higher seed vigor index of 973.7 and 948.8, respectively, as compared to untreated control 636.5. Furthermore, both the isolates significantly increased plant height as well as the fresh and dry weight of chilli plants under the rolled paper towel method. Morphological, biochemical, and molecular characterization identified Bacillus amyloliquefaciens (MH491049) as the key antagonist. This study demonstrates that rhizobacteria, specifically Iso 32 and Iso 24, can effectively protect chilli plants against Fusarium wilt while promoting overall plant development. These findings hold promise for sustainable and eco-friendly management of Fusarium wilt in chilli cultivation.

A smooth vetch (Vicia villosa var.) strain endogenous to the broad-spectrum antagonist Bacillus siamensis JSZ06 alleviates banana wilt disease.

Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense Tropical Race 4 (Foc TR4), poses a significant threat to banana production globally, thereby necessitating effective biocontrol methods to manage this devastating disease. This study investigates the potential of Bacillus siamensis strain JSZ06, isolated from smooth vetch, as a biocontrol agent against Foc TR4. To this end, we conducted a series of in vitro and in vivo experiments to evaluate the antifungal activity of strain JSZ06 and its crude extracts. Additionally, genomic analyses were performed to identify antibiotic synthesis genes, while metabolomic profiling was conducted to characterize bioactive compounds. The results demonstrated that strain JSZ06 exhibited strong inhibitory activity against Foc TR4, significantly reducing mycelial growth and spore germination. Moreover, scanning and transmission electron microscopy revealed substantial ultrastructural damage to Foc TR4 mycelia treated with JSZ06 extracts. Genomic analysis identified several antibiotic synthesis genes, and metabolomic profiling revealed numerous antifungal metabolites. Furthermore, in pot trials, the application of JSZ06 fermentation broth significantly enhanced banana plant growth and reduced disease severity, achieving biocontrol efficiencies of 76.71% and 79.25% for leaves and pseudostems, respectively. In conclusion, Bacillus siamensis JSZ06 is a promising biocontrol agent against Fusarium wilt in bananas, with its dual action of direct antifungal activity and plant growth promotion underscoring its potential for integrated disease management strategies.