Genome-Wide Identification, Expression, and Response to Fusarium Infection of the SWEET Gene Family in Garlic (Allium sativum L.).

Proteins of the SWEET (Sugar Will Eventually be Exported Transporters) family play an important role in plant development, adaptation, and stress response by functioning as transmembrane uniporters of soluble sugars. However, the information on the SWEET family in the plants of the Allium genus, which includes many crop species, is lacking. In this study, we performed a genome-wide analysis of garlic (Allium sativum L.) and identified 27 genes putatively encoding clade I-IV SWEET proteins. The promoters of the A. sativum (As) SWEET genes contained hormone- and stress-sensitive elements associated with plant response to phytopathogens. AsSWEET genes had distinct expression patterns in garlic organs. The expression levels and dynamics of clade III AsSWEET3, AsSWEET9, and AsSWEET11 genes significantly differed between Fusarium-resistant and -susceptible garlic cultivars subjected to F. proliferatum infection, suggesting the role of these genes in the garlic defense against the pathogen. Our results provide insights into the role of SWEET sugar uniporters in A. sativum and may be useful for breeding Fusarium-resistant Allium cultivars.

Two regulators of G-protein signaling (RGS) proteins FlbA1 and FlbA2 differentially regulate fumonisin B1 biosynthesis in Fusarium verticillioides.

Fumonisins are a group of mycotoxins produced by maize pathogen Fusarium verticillioides that pose health concerns to humans and animals. Yet we still lack a clear understanding of the mechanism of fumonisins regulation during pathogenesis. The heterotrimeric G protein complex, which consists of canonical subunits and various regulators of G-protein signaling (RGS) proteins, plays an important role in transducing signals under environmental stress. Earlier studies demonstrated that Gα and Gß subunits are positive regulators of fumonisin B1 (FB1) biosynthesis and that two RGS genes, FvFlbA1 and FvFlbA2, were highly upregulated in Gß deletion mutant ∆Fvgbb1. Notably, FvFlbA2 has a negative role in FB1 regulation. While many fungi contain a single copy of FlbA, F. verticillioides harbors two putative FvFlbA paralogs, FvFlbA1 and FvFlbA2. In this study, we further characterized functional roles of FvFlbA1 and FvFlbA2. While ∆FvflbA1 deletion mutant exhibited no significant defects, ∆FvflbA2 and ∆FvflbA2/A1 mutants showed thinner aerial hyphal growth while promoting FB1 production. FvFlbA2 is required for proper expression of key conidia regulation genes, including putative FvBRLA, FvWETA, and FvABAA, while suppressing FUM21, FUM1, and FUM8 expression. Split luciferase assays determined that FvFlbA paralogs interact with key heterotrimeric G protein components, which in turn will lead altered G-protein-mediated signaling pathways that regulate FB1 production and asexual development in F. verticillioides.

Inhibiting miR-129-5p alleviates inflammation and modulates autophagy by targeting ATG14 in fungal keratitis.

To investigate the role of miR-129-5p in inflammation and autophagy in fungal keratitis, we established a keratitis mouse model infected with Fusarium solani (F. solani) and conducted experiments on corneal stromal cells infected with F. solani. The expression of miR-129-5p was detected via quantitative real-time polymerase chain reaction (PCR). The miR-129-5p antagomir was used to transfect cells and mice to study the regulatory role of miR-129-5p in autophagy and inflammation after fungal infection. The expression of Beclin1 and LC3B and colocalization of LC3B with lysosomes were detected via Western blotting and immunofluorescence. CCK-8 was used to determine the viability of corneal stromal cells. The expression of IL-1ß were detected by ELISA. Bioinformatics software was used to predict the potential targets of miR-129-5p, which were verified by a luciferase reporter gene assay. RT-PCR showed that miR-129-5p expression in mouse corneas was significantly increased after infection with F. solani. Subconjunctival injection of the miR-129-5p antagomir significantly enhanced the proteins Beclin-1 and LC3B. At the same time, inhibiting miR-129-5p expression could reduce the inflammatory response in FK and significantly increase the viability of corneal stromal cells infected with F. solan. Moreover, the dual luciferase reporter assay indicated that Atg14 was a direct target of miR-129-5p. Our study shows that miR-129-5p is a novel small molecule that regulates autophagy by targeting Atg14, indicating that it may be a proinflammatory and therapeutic target for fungal keratitis.

Expression Analysis of MaTGA8 Transcription Factor in Banana and Its Defence Functional Analysis by Overexpression in Arabidopsis.

TGA transcription factor is a member of the D subfamily of the basic region-leucine zippers (bZIP) family. It is a type of transcription factor that was first identified in plants and is the main regulator in plant development and physiological processes, including morphogenesis and seed formation in response to abiotic and biotic stress and maintaining plant growth. The present study examined the sequence of the MaTGA8 transcription factor, the sequence of which belonged to subfamily D of the bZIP and had multiple cis-acting elements such as the G-box, TCA-element, TGACG-element, and P-box. Quantitative real time polymerase chain reaction (qRT-PCR) analyses showed that MaTGA8 was significantly down-regulated by the soil-borne fungus Fusarium oxysporum f. sp. cubense race 4 (Foc TR4). Under the induction of salicylic acid (SA), MaTGA8 was down-regulated, while different members of the MaNPR1 family responded significantly differently. Among them, MaNPR11 and MaNPR3 showed an overall upward trend, and the expression level of MaNPR4, MaNPR8, and MaNPR13 was higher than other members. MaTGA8 is a nuclear-localized transcription factor through strong interaction with MaNPR11 or weaker interaction with MaNPR4, and it is implied that the MaPR gene can be activated. In addition, the MaTGA8 transgenic Arabidopsis has obvious disease resistance and higher chlorophyll content than the wild-type Arabidopsis with the infection of Foc TR4. These results indicate that MaTGA8 may enhance the resistance of bananas to Foc TR4 by interacting with MaNPR11 or MaNPR4. This study provides a basis for further research on the application of banana TGA transcription factors in Foc TR4 stress and disease resistance and molecular breeding programs.

Fusarium infection alters the m6A-modified transcript landscape in the cornea.

N6-methyladenosine (m6A) is the most common post-transcriptional modification of RNA in eukaryotes that regulates the post-transcriptional expression level of genes without changing the base sequence. The role of m6A in fungal keratitis has not yet been elucidated. Here, we aimed to identify m6A modification changes and their potential roles in fungal keratitis. The murine model of fungal keratitis was established by inoculating mice with Fusarium solani (F. solani). The overall m6A level was detected via an m6A RNA methylation assay kit. The expression levels of key m6A modification-related genes were estimated by quantitative real-time polymerase chain reaction (PCR). The expression and localization of METTL (methyltransferase like)3, the key component of the m6A methyltransferase complex, was determined by immunostaining and Western blotting (WB). Immunoprecipitation methylation microarray was used to describe the changes in m6A modification in F. solani-infected corneal tissue. The overall m6A level in corneal tissue on the 5th day in the F. solani-treated group was upregulated compared with that in the control group. The demethylase levels were unaltered, but the level of the methylase METTL3 was increased significantly after fungal infection. Additionally, differences were found in m6A modifications in 1137 mRNAs, of which 780 were hypermethylated and 357 were hypomethylated. To the best of our knowledge, the present work is the first investigation on the m6A modification profiles in experimental fungal keratitis, and it may provide a potential therapeutic target.

Metabolic Changes of Fusarium graminearum Induced by TPS Gene Deletion.

Fusarium head blight (FHB) mainly resulting from Fusarium graminearum (Fg) Schwabe is a notorious wheat disease causing huge losses in wheat production globally. Fg also produces mycotoxins, which are harmful to human and domestic animals. In our previous study, we obtained two Fg mutants, TPS1- and TPS2-, respectively, with a single deletion of trehalose 6-phosphate synthase (TPS1) and trehalose 6-phosphate phosphatase (TPS2) compared with the wild type (WT). Both mutants were unable to synthesize trehalose and produced fewer mycotoxins. To understand the other biochemical changes induced by TPS gene deletion in Fg, we comprehensively analyzed the metabolomic differences between TPS- mutants and the WT using NMR together with gas chromatography-flame ionization detection/mass spectrometry. The expression of some relevant genes was also quantified. The results showed that TPS1- and TPS2- mutants shared some common metabolic feature such as decreased levels for trehalose, Val, Thr, Lys, Asp, His, Trp, malonate, citrate, uridine, guanosine, inosine, AMP, C10:0, and C16:1 compared with the WT. Both mutants also shared some common expressional patterns for most of the relevant genes. This suggests that apart from the reduced trehalose biosynthesis, both TPS1 and TPS2 have roles in inhibiting glycolysis and the tricarboxylic acid cycle but promoting the phosphopentose pathway and nucleotide synthesis; the depletion of either TPS gene reduces the acetyl-CoA-mediated mycotoxin biosynthesis. TPS2- mutants produced more fatty acids than TPS1- mutants, suggesting different roles for TPS1 and TPS2, with TPS2- mutants having impaired trehalose biosynthesis and trehalose 6-phosphate accumulation. This may offer opportunities for developing new fungicides targeting trehalose biosynthesis in Fg for FHB control and mycotoxin reduction in the FHB-affected cereals.

Intron-mediated regulation of ß-tubulin genes expression affects the sensitivity to carbendazim in Fusarium graminearum.

The plant pathogenic fungus, Fusarium graminearum, is known to have two ß-tubulin genes (named Fg-ß1tub and Fg-ß2tub). Mutations in Fg-ß2tub rather than in Fg-ß1tub have been shown to confer resistance to carbendazim (MBC), even though Fg-ß1tub has higher homology than Fg-ß2tub to the ß-tubulin isotypes related to benzimidazole resistance in other fungi. However, sequence alignment of ß-tubulin isotypes related to benzimidazole resistance showed that the number and position of introns in Fg-ß2tub are more consistent than Fg-ß1tub to those in other ß-tubulin genes. In detail, Fg-ß1tub lacks three introns, i.e., intron i3, i4, and i6 corresponding to positions in Fg-ß2tub of F. graminearum. To investigate the effects of the divergence introns on the function of ß-tubulins in F. graminearum, a strategy of intron deletion and insertion was used. Our results showed that deletion of the second intron from Fg-ß1tub gene increased Fg-ß1tub expression levels leading to increased sensitivity to MBC. Besides, inserting the divergence introns into Fg-ß1tub can increase Fg-ß1tub expression leading to increased sensitivity to MBC. In addition, intron-mediated Fg-ß1tub gene expression requires a splicing-competent intron within the body of the host gene. Furthermore, the insertion and deletion of introns in Fg-ß1tub gene have no significant effect on hyphal growth, conidiation and virulence in F. graminearum. Thus, we proposed that introns may be among the factors contributing to the evolution and functional divergence of two ß-tubulin genes and also significantly regulate the expression of ß-tubulin genes, which, in turn, affects sensitivity to MBC fungicides in F. graminearum.

Comparative genomics of geographically distant Fusarium fujikuroi isolates revealed two distinct pathotypes correlating with secondary metabolite profiles.

Fusarium fujikuroi causes bakanae ("foolish seedling") disease of rice which is characterized by hyper-elongation of seedlings resulting from production of gibberellic acids (GAs) by the fungus. This plant pathogen is also known for production of harmful mycotoxins, such as fusarins, fusaric acid, apicidin F and beauvericin. Recently, we generated the first de novo genome sequence of F. fujikuroi strain IMI 58289 combined with extensive transcriptional, epigenetic, proteomic and chemical product analyses. GA production was shown to provide a selective advantage during infection of the preferred host plant rice. Here, we provide genome sequences of eight additional F. fujikuroi isolates from distant geographic regions. The isolates differ in the size of chromosomes, most likely due to variability of subtelomeric regions, the type of asexual spores (microconidia and/or macroconidia), and the number and expression of secondary metabolite gene clusters. Whilst most of the isolates caused the typical bakanae symptoms, one isolate, B14, caused stunting and early withering of infected seedlings. In contrast to the other isolates, B14 produced no GAs but high amounts of fumonisins during infection on rice. Furthermore, it differed from the other isolates by the presence of three additional polyketide synthase (PKS) genes (PKS40, PKS43, PKS51) and the absence of the F. fujikuroi-specific apicidin F (NRPS31) gene cluster. Analysis of additional field isolates confirmed the strong correlation between the pathotype (bakanae or stunting/withering), and the ability to produce either GAs or fumonisins. Deletion of the fumonisin and fusaric acid-specific PKS genes in B14 reduced the stunting/withering symptoms, whereas deletion of the PKS51 gene resulted in elevated symptom development. Phylogenetic analyses revealed two subclades of F. fujikuroi strains according to their pathotype and secondary metabolite profiles.

Genetic diversity of Fusarium mexicanum, causal agent of mango and big-leaf mahogany malformation in Mexico.

In Mexico, Fusarium mexicanum has been reported causing mango malformation disease and big-leaf mahogany malformation disease. Our objective was to determine the genetic diversity of F. mexicanum isolates obtained from malformed big-leaf mahogany and mango trees, using an internal simple sequence repeat (ISSR) analysis. A total of 61 isolates of F. mexicanum, 32 from mango and 29 from big-leaf mahogany, were initially genotyped using fourteen ISSR primers. Data from five primers that produced the highest number of polymorphic bands were selected for further analysis. The primers generated 49 polymorphic bands (85.96%) from a total of 57 fragments ranging in size from 250 to 2800 bp, with an average of 11.4 bands per primer. An analysis of molecular variance (AMOVA) indicated that the variation within populations, isolates grouped by host and geographic origin, was significant (43%), followed by the variation between the big-leaf mahogany versus mango isolates (34%), while among populations the variation was the lowest (22%). The genetic fingerprints suggested that genetic variability of F. mexicanum populations are structured by the host of origin rather than the geographic region.

Combined De Novo Transcriptome and Metabolome Analysis of Common Bean Response to Fusarium oxysporum f. sp. phaseoli Infection.

Molecular changes elicited by common bean (Phaseolus vulgaris L.) in response to Fusarium oxysproum f. sp. Phaseoli (FOP) remain elusive. We studied the changes in root metabolism during common bean-FOP interactions using a combined de novo transcriptome and metabolome approach. Our results demonstrated alterations of transcript levels and metabolite concentrations in common bean roots 24 h post infection as compared to control. The transcriptome and metabolome responses in common bean roots revealed significant changes in structural defense i.e., cell-wall loosening and weakening characterized by hyper accumulation of cell-wall loosening and degradation related transcripts. The levels of pathogenesis related genes were significantly higher upon FOP inoculation. Interestingly, we found the involvement of glycosylphosphatidylinositol- anchored proteins (GPI-APs) in signal transduction in response to FOP infection. Our results confirmed that hormones have strong role in signaling pathways i.e., salicylic acid, jasmonate, and ethylene pathways. FOP induced energy metabolism and nitrogen mobilization in infected common bean roots as compared to control. Importantly, the flavonoid biosynthesis pathway was the most significantly enriched pathway in response to FOP infection as revealed by the combined transcriptome and metabolome analysis. Overall, the observed modulations in the transcriptome and metabolome flux as outcome of several orchestrated molecular events are determinant of host's role in common bean-FOP interactions.

Two Cdc2 Kinase Genes with Distinct Functions in Vegetative and Infectious Hyphae in Fusarium graminearum.

Eukaryotic cell cycle involves a number of protein kinases important for the onset and progression through mitosis, most of which are well characterized in the budding and fission yeasts and conserved in other fungi. However, unlike the model yeast and filamentous fungi that have a single Cdc2 essential for cell cycle progression, the wheat scab fungus Fusarium graminearum contains two CDC2 orthologs. The cdc2A and cdc2B mutants had no obvious defects in growth rate and conidiation but deletion of both of them is lethal, indicating that these two CDC2 orthologs have redundant functions during vegetative growth and asexual reproduction. However, whereas the cdc2B mutant was normal, the cdc2A mutant was significantly reduced in virulence and rarely produced ascospores. Although deletion of CDC2A had no obvious effect on the formation of penetration branches or hyphopodia, the cdc2A mutant was limited in the differentiation and growth of infectious growth in wheat tissues. Therefore, CDC2A plays stage-specific roles in cell cycle regulation during infectious growth and sexual reproduction. Both CDC2A and CDC2B are constitutively expressed but only CDC2A was up-regulated during plant infection and ascosporogenesis. Localization of Cdc2A- GFP to the nucleus but not Cdc2B-GFP was observed in vegetative hyphae, ascospores, and infectious hyphae. Complementation assays with chimeric fusion constructs showed that both the N- and C-terminal regions of Cdc2A are important for its functions in pathogenesis and ascosporogenesis but only the N-terminal region is important for its subcellular localization. Among the Sordariomycetes, only three Fusarium species closely related to F. graminearum have two CDC2 genes. Furthermore, F. graminearum uniquely has two Aurora kinase genes and one additional putative cyclin gene, and its orthologs of CAK1 and other four essential mitotic kinases in the budding yeast are dispensable for viability. Overall, our data indicate that cell cycle regulation is different between vegetative and infectious hyphae in F. graminearum and Cdc2A, possibly by interacting with a stage-specific cyclin, plays a more important role than Cdc2B during ascosporogenesis and plant infection.

Fusarium Toxins in Cereals: Occurrence, Legislation, Factors Promoting the Appearance and Their Management.

Fusarium diseases of small grain cereals and maize cause significant yield losses worldwide. Fusarium infections result in reduced grain yield and contamination with mycotoxins, some of which have a notable impact on human and animal health. Regulations on maximum limits have been established in various countries to protect consumers from the harmful effects of these mycotoxins. Several factors are involved in Fusarium disease and mycotoxin occurrence and among them environmental factors and the agronomic practices have been shown to deeply affect mycotoxin contamination in the field. In the present review particular emphasis will be placed on how environmental conditions and stress factors for the crops can affect Fusarium infection and mycotoxin production, with the aim to provide useful knowledge to develop strategies to prevent mycotoxin accumulation in cereals.

Interleukin 17 expression in peripheral blood neutrophils from fungal keratitis patients and healthy cohorts in southern India.

Interleukin 17A (IL-17) production by peripheral blood neutrophils was examined in patients with fungal keratitis and in uninfected individuals in southern India, which has high levels of airborne Aspergillus and Fusarium conidia. Il17a gene expression and intracellular IL-17 were detected in all groups, although levels were significantly elevated in neutrophils from patients with keratitis. There were no significant differences in plasma IL-17 and IL-23 between patients with keratitis and uninfected individuals; however, combined data from all groups showed a correlation between the percentage IL-17 producing neutrophils and plasma IL-23, and between plasma IL-17 and IL-6 and IL-23.

Identification of differentially expressed genes from Trichoderma harzianum during growth on cell wall of Fusarium solani as a tool for biotechnological application.

BACKGROUND: The species of T. harzianum are well known for their biocontrol activity against many plant pathogens. However, there is a lack of studies concerning its use as a biological control agent against F. solani, a pathogen involved in several crop diseases. In this study, we have used subtractive library hybridization (SSH) and quantitative real-time PCR (RT-qPCR) techniques in order to explore changes in T. harzianum genes expression during growth on cell wall of F. solani (FSCW) or glucose. RT-qPCR was also used to examine the regulation of 18 genes, potentially involved in biocontrol, during confrontation between T. harzianum and F. solani. RESULTS: Data obtained from two subtractive libraries were compared after annotation using the Blast2GO suite. A total of 417 and 78 readable EST sequence were annotated in the FSCW and glucose libraries, respectively. Functional annotation of these genes identified diverse biological processes and molecular functions required during T. harzianum growth on FSCW or glucose. We identified various genes of biotechnological value encoding to proteins which function such as transporters, hydrolytic activity, adherence, appressorium development and pathogenesis. Fifteen genes were up-regulated and sixteen were down-regulated at least at one-time point during growth of T. harzianum in FSCW. During the confrontation assay most of the genes were up-regulated, mainly after contact, when the interaction has been established. CONCLUSIONS: This study demonstrates that T. harzianum expressed different genes when grown on FSCW compared to glucose. It provides insights into the mechanisms of gene expression involved in mycoparasitism of T. harzianum against F. solani. The identification and evaluation of these genes may contribute to the development of an efficient biological control agent.

Use of molecular markers to compare Fusarium verticillioides pathogenic strains isolated from plants and humans.

Fusarium verticillioides is a pathogen of agriculturally important crops, especially maize. It is considered one of the most important pathogens responsible for fumonisin contamination of food products, which causes severe, chronic, and acute intoxication in humans and animals. Moreover, it is recognized as a cause of localized infections in immunocompetent patients and disseminated infections among severely immunosuppressed patients. Several molecular tools have been used to analyze the intraspecific variability of fungi. The objective of this study was to use molecular markers to compare pathogenic isolates of F. verticillioides and isolates of the same species obtained from clinical samples of patients with Fusarium mycoses. The molecular markers that we used were inter-simple sequence repeat markers (primers GTG5 and GACA4), intron splice site primer (primer EI1), random amplified polymorphic DNA marker (primer OPW-6), and restriction fragment length polymorphism-internal transcribed spacer (ITS) from rDNA. From the data obtained, clusters were generated based on the UPGMA clustering method. The amplification products obtained using primers ITS4 and ITS5 and loci ITS1-5.8-ITS2 of the rDNA yielded fragments of approximately 600 bp for all the isolates. Digestion of the ITS region fragment using restriction enzymes such as EcoRI, DraI, BshI, AluI, HaeIII, HinfI, MspI, and PstI did not permit differentiation among pathogenic and clinical isolates. The inter-simple sequence repeat, intron splice site primer, and random amplified polymorphic DNA markers presented high genetic homogeneity among clinical isolates in contrast to the high variability found among the phytopathogenic isolates of F. verticillioides.

Mapping of quantitative trait loci for traits linked to fusarium head blight in barley.

Fusarium head blight (FHB) is a devastating disease occurring in small grain cereals worldwide. The disease results in the reduction of grain yield, and mycotoxins accumulated in grain are also harmful to both humans and animals. It has been reported that response to pathogen infection may be associated with the morphological and developmental traits of the host plant, e.g. earliness and plant height. Despite many studies, effective markers for selection of barley genotypes with increased resistance to FHB have not been developed. In the present study, we investigated 100 recombinant inbred lines (RIL) of spring barley. Plants were examined in field conditions (three locations) in a completely randomized design with three replications. Barley genotypes were artificially infected with spores of Fusarium culmorum before heading. Apart from the main phenotypic traits (plant height, spike characteristic, grain yield), infected kernels were visually scored and the content of deoxynivalenol (DON) mycotoxin was investigated. A set of 70 Quantitative Trait Loci (QTLs) were detected through phenotyping of the mapping population in field conditions and genotyping using a barley Ilumina 9K iSelect platform. Six loci were detected for the FHB index on chromosomes 2H, 3H, 5H, and 7H. A region on the short arm of chromosome 2H was detected in which many QTLs associated with FHB- and yield-related traits were found. This study confirms that agromorphological traits are tightly related to FHB and should be taken into consideration when breeding barley plants for FHB resistance.

Unravelling the genetic basis of Fusarium seedling rot resistance in the MAGIC maize population: novel targets for breeding.

Fungal infection by Fusarium verticillioides is cause of prevalent maize disease leading to substantial reductions in yield and grain quality worldwide. Maize resistance to the fungus may occur at different developmental stages, from seedling to maturity. The breeding of resistant maize genotypes may take advantage of the identification of quantitative trait loci (QTL) responsible for disease resistance already commenced at seedling level. The Multi-parent Advance Generation Intercross (MAGIC) population was used to conduct high-definition QTL mapping for Fusarium seedling rot (FSR) resistance using rolled towel assay. Infection severity level, seedling weight and length were measured on 401 MAGIC maize recombinant inbred lines (RILs). QTL mapping was performed on reconstructed RIL haplotypes. One-fifth of the MAGIC RILs were resistant to FSR and 10 QTL were identified. For FSR, two QTL were detected at 2.8 Mb and 241.8 Mb on chromosome 4, and one QTL at 169.6 Mb on chromosome 5. Transcriptomic and sequencing information generated on the MAGIC founder lines was used to guide the identification of eight candidate genes within the identified FSR QTL. We conclude that the rolled towel assay applied to the MAGIC maize population provides a fast and cost-effective method to identify QTL and candidate genes for early resistance to F. verticillioides in maize.

Multiplex Polymerase Chain Reaction Assay for Screening of Mycotoxin Genes From Ocular Isolates of Fusarium species.

PURPOSE: To identify mycotoxin genes among clinical ocular isolates of Fusarium species and to correlate these with clinical outcomes of Fusarium keratitis. METHODS: Fifty-four clinical isolates of Fusarium were retrieved from the Bascom Palmer Eye Institute Ocular Microbiology Laboratory data bank. Multiplex polymerase chain reactions were run to confirm the identification of Fusarium species [internal transcribed spacer sequence, translation elongation factor 1-α (TEF) and ß-tubulin] and to detect the presence of genes encoding production of fumonisin B mycotoxins (FUM1 and FUM8) and trichothecene mycotoxins (deoxynivalenol and nivalenol). The presence or absence of mycotoxins was compared with patient outcomes. RESULTS: Forty-three (79%) of the 54 isolates were confirmed as Fusarium species, by an internal transcribed spacer sequence in 3 (5.6%) and by TEF in 43 (79.6%) of the 54 isolates. Fumonisin biosynthetic gene 1 (FUM1) was detected in 57.4% (n = 31/54) of the Fusarium isolates. No FUM8, deoxynivalenol genes, and nivalenol genes were detected among these in the clinical isolates group. Initial best-corrected visual acuity ranged from 20/25 to 20/80 in the FUM1 gene-negative group and from 20/20 to light perception in the FUM1 gene-positive group. There was no difference in the time to cure between both groups. The presence of FUM1 genes in 5 fungal isolates seemed to be associated with progression to penetrating keratoplasty in the 5 patients from whom the fungi were isolated. Fusarium solani was recovered from all patients requiring penetrating keratoplasty. CONCLUSIONS: Fumonisin B biosynthetic gene 1 may be common among clinical Fusarium isolates and contribute to worse initial visual acuity and high-risk progression to penetrating keratoplasty.