When the fungal pathogen Gibberella moniliformis (anamorph, Fusarium verticillioides) colonizes maize and maize-based prod- ucts, it produces class B fumonisin (FB) mycotoxins, which are a significant threat to human and animal health. FB biosynthetic enzymes and accessory proteins are encoded by a set of clustered and cotranscribed genes collectively named FUM, whose molec- ular regulation is beginning to be unraveled by researchers. FB accumulation correlates with the amount of transcripts from the key FUM genes, FUM1, FUM21, and FUM8. In fungi in general, gene expression is often partially controlled at the chromatin level in secondary metabolism; when this is the case, the deacetylation and acetylation (and other posttranslational modifica- tions) of histones are usually crucial in the regulation of transcription. To assess whether epigenetic factors regulate the FB path- way, we monitored FB production and FUM1, FUM21, and FUM8 expression in the presence of a histone deacetylase inhibitor and verified by chromatin immunoprecipitation the relative degree of histone acetylation in the promoter regions of FUM1, FUM21, and FUM8 under FB-inducing and noninducing conditions. Moreover, we generated transgenic F. verticillioides strains expressing GFP under the control of the FUM1 promoter to determine whether its strength under FB-inducing and noninducing conditions was influenced by its location in the genome. Our results indicate a clear and differential role for chromatin remodel- ing in the regulation of FUM genes. This epigenetic regulation can be attained through the modulation of histone acetylation at the level of the promoter regions of the key biosynthetic genes FUM1 and FUM21, but less so for FUM8.
A. Maize Seeds Health Testing: The testing result of maize seeds health with blotter test showed that there were 11 species maize seed-born fungi. There were yaitu Fusarium verticillioides (40%), Penici- llium oxalicum (24%), Penicillium sp. (14%), Aspergillus niger (4%), Aspergillus flavus (3.5%), Curvularia sp. (1.5%), Rhizoctonia sp. (1.5%), Rhizopus sp. (1.5%), Alternaria sp. (1.5%), Clado- sporium sp. (1%), and Drechslera sp. (0.5%). Schutless et al., (2002) said that fungi which are frequently found to infect maize in Indonesia are Aspergillus flavus, Fusarium verticillioides, Asper- gillus niger, Eurotium rubrum. Furthermore, F. verticillioides and P. oxalicum are used as fungi model in fungal detection using fluorescence spectroscopy method.
Introduction Fusarium verticillioides (Sacc.) Nirenberg. (synonym F. moniliforme J. Sheld) is commonly associated with maize kernels and under favorable conditions causes an ear rot known as Fusarium ear rot (White, 1999). The disease reduces seed quality and recently the fungus has been shown to produce the mycotoxin fumonisin, which is toxic to animals and an implicated human carcinogen. Maize growers in North Carolina have experienced elevated fumonisin levels in harvested grain in the past 5 years. This problem came to the forefront in 1998 when loads of maize were rejected at the grain-buying stations. Some stations had purchased ELISA tests to determine fumonisin content of the grain and set an arbitrary limit at 15 ppm for the grain they would purchase. Several loads of maize were rejected and one load was found to contain fumonisin contamination of 278 ppm. Other stations were assaying maize and rejecting loads of grain based on elevated levels of rotten kernels. While fumonisin contamination has not been as severe in recent years as compared to 1998, maize growers have been requesting information on seed resistance to F. verticillioides. Because no hybrids contain adequate levels of resistance to the fungus, cultural methods may be the only way to limit fumonisin in harvested grain.
99 Read more
The secondary metabolite gene clusters of euascomycete fungi are among the largest known clusters of functionally related genes in eukaryotes. Most of these clusters are species specific or genus specific, and little is known about how they are formed during evolution. We used a comparative genomics approach to study the evolutionary origins of a secondary metabolite cluster that synthesizes a polyketide derivative, namely, the fumonisin (FUM) cluster of Fusarium verticillioides, and that of Aspergillus niger another fumonisin (fumonisin B) producing species. We identified homologs in other euascomycetes of the Fusarium verticillioides FUM genes and their flanking genes. We discuss four models for the origin of the FUM cluster in Fusarium verticillioides and argue that two of these are plausible: (i) assembly by relocation of initially scattered genes in a recent Fusarium verticillioides; or (ii) horizontal transfer of the FUM cluster from a distantly related Sordariomycete species. We also propose that the FUM cluster was horizontally transferred into Aspergillus niger, most probably from a Sordariomycete species.
Sugarcane plant samples affected by the disease pokkah boeng were collected from the major sugarcane produc- ing areas in Iran. Fifty isolates of Fusarium verticillioides were recovered from diseased sugarcanes. Results of pathogenicity tests revealed that all isolates were pathogenic to sugarcane. Four hundred and eighty-five nitrate non-utilising mutants were generated from F. verticillioides isolates. Media used for nit mutant generation in- cluded potato dextrose agar, minimal medium and Czapeck agar amended with 1.8%, 2%, 2.5%, and 3% potassium chlorate. Nit mutants were divided into three phenotypic (nit1, nit3, and nitM) classes based on their growth on different nitrogen sources in the culture media. Among the isolates tested, 280, 115 and 90 nit1, nit3, and nit M were generated, respectively. Nit mutants were used to force the heterokaryon formation to determine the distribution of VCGs and their relation to pathogenicity and geographic origin. Forty-eight VCGs of F. verticil- lioides were isolated from sugarcane. Forty-six of the VCGs were represented by a single isolate, whereas the remaining two comprised two isolates. None of the VCGs was common.
Abstract: Fusarium verticillioides is a widely distributed mitosporic pathogen of maize, able to cause corn seedling blight, root rot, stalk rot and kernel or ear rot. Synthetic fungicides and some crop management practices are also not advisable in the control of this pathogen because chemical fungicide result in environmental pollution or hazards. Antagonistic micro-biological agents (bioagents) can be recommended to farmers because it is cheaper and environmental friendly. This aim of this study was to assess the efficiency of antagonistic micro organisms in the control of Fusarium verticillioides of maize. The efficacy of micro-biological agents: Trichoderma viride, T. pseudokoningii, T. harzianum and Bacillus subtilis were assessed in vitro. Laid in the laboratory in a Completely Randomized Design (CRD) and subjected to analysis of variance using SAS, 2001. The four antagonistic bioagents showed different inhibitory effect in the control of F.verticillioides. T. viride and T. pseudokoningii were the most effective antagonists; they caused significant inhibitory effect on the growth of F.verticillioides by 0.75cm and 0. 72cm compared to the control which was 2.57cm respectively at 120 hours of incubation. T. harzianum and B. subtilis had the least inhibitory effect against the pathogen. There was a significant inhibition in the growth of F. verticillioides at < 0.05 when paired with all the micro-biological agents used. The introduction of the antagonist before the pathogen in vitro was observed to be the best followed by the simultaneous pairing, and the least inhibition was when the introduction of the antagonist 24 hours after the pathogen. It was observed that all the antagonists tested had good inhibitory potentials on the pathogen, F. verticillioides.
Due to the absence of aerial hyphae, the hydrophobicity of the cell surface was investigated. Water droplets (30 l each) with or without acid fuchsin were placed on the surfaces of 7-day-old colonies of wild-type, Fvve1, FvvelB, FvvelC, and complemented strains grown on PDA medium. On colonies of wild-type, FvvelC, and complemented strains, the water droplets remained on the surface of the mycelium without extending or being absorbed for quite a long time (at least 1 h). In contrast, the strains carrying mutations in Fvve1 and FvvelB displayed a phenotype quite different from those of wild-type and FvvelC strains. The water droplets on the Fvve1 and FvvelB strains were immediately spread and absorbed (Fig. 2A). FvVE1 regulates expression of hydrophobin genes (28). Transcriptional analysis by qRT-PCR showed that compared with findings for the wild-type strain and the FvvelB[FvVELB] strain, the transcriptional levels of HYD3 and HYD4 were dramatically low in the FvvelB strain, and HYD1 and HYD2 were completely blocked by FvvelB (Fig. 2D). These data, FIG 1 Identification of FvVE1-associated proteins in Fusarium verticillioides. (A) Proteins interacting with FvVE1 from the FvVE1–5 ⫻ c-Myc– 6 ⫻ His strain (FvVE1 ko : FvVE1-MYC-HIS) were isolated with 4 to 15% gradient SDS polyacrylamide gels and stained with silver. Proteins from the wild type (WT) isolated by
10 Read more
The maize pathogen Fusarium verticillioides (teleomorph Gibberella moniliformis) can infect maize throughout the world and can cause disease of ears, stalks, and seedlings (29). On some occasions, this fungus can synthesize the fumonisin fam- ily of mycotoxins, which, after ingestion, have been associated with a number of animal diseases, including cancer (15), and have been epidemiologically associated with human esopha- geal cancer in some regions of the world (23). Of recent con- cern are findings that fumonisins can disrupt neural tube de- velopment in rodents and, based on human epidemiological surveys, may increase the risks of human neural tube defects (24). Fumonisins are structurally similar to the sphingolipid sphinganine and disrupt sphingolipid metabolism by inhibiting the enzyme ceramide synthase (37 and references therein). Sphingolipids play a critical role in cell membranes and a variety of cell signaling pathways. Thus, disruption of sphingo-
DOI: 10.4236/ajps.2019.105055 757 American Journal of Plant Sciences Even though T. harzianum strain 2 seemed to be the most effective antagonist against the pathogen within the stem tissues in another experiment , seeds from the plants that received “Inoculation of T. harzianum strain 2 alone” and two other different treatment combinations of the fungus ( i.e. “Inoculation of pathogen before T. harzianum strain 2” and “Inoculation of T. harzianum strain 2 and pathogen simultaneously”) contained a comparatively high content of fu- monisin. The same could be said of two of the treatment combinations of T. hamatum ( i.e. “Inoculating pathogen before T. hamatum ” and “Inoculating T. hamatum and pathogen simultaneously”) even though “Inoculating T. hamatum alone ” gave the lowest fumonisin concentration in the seeds. Even though this might be interpreted that the treatments applied on the stem had little or no ef- fect on the fumonisin content and hence Fusarium occurrence in the seeds, this, however could not be said to be totally true. This is because seeds with the lowest fumonisin content were also obtained from plants whose stems received treat- ments involving the same fungi ( i.e. “Inoculation of T. hamatum alone” and “Inoculation of T. harzianum strain 2 before pathogen”). This low fumonisin content might not be unconnected with the presence of the two Trichoderma species. The antagonists might have moved up the stem through the parenchyma tissue into the cob as concluded by  thereafter reducing Fusarium occur- rence in the seeds. Perhaps T. hamatum and/or T. harzianum strain 2 isolated from maize plant parts might be used, just like T. viride employed by  to suppress the radial colony extension of Fusarium verticillioides on agar as well as the fumonisin B 1 (FB 1 ) on corn kernels. In line with their suggestions for T.
The present study was conducted to identify the antifungal activity of phenolic compounds extracted from the mangrove, Rhizophora mangle against the Fusarium verticillioides isolates DA42, F64 and PO3. The total phenolic content was calculated using the Folin-Ciocalteu method. The in vitro inhibition test was performed according to the poisoned food technique. Stem extracts had the highest total phenolic content (9.5 mg gallic acid equivalents/g dry biomass) and displayed major inhibition percentages against all Fusarium verticillioides isolates. Furthermore, the concentration of the stem extract required to inhibit the three fungal isolates by 50 %, is 2 to 3 times greater on average than that required for leaf and root extracts. This study demonstrated the inhibitory activity of ethanol extracts of Rhizophora mangle roots, stems and leaves against different isolates of Fusarium verticillioides.
Aspergillus flavus and Fusarium verticillioides are capable of infecting maize kernels and producing mycotoxins. Pathogenesis and host response in these host-parasite interactions remain poorly understood. In this study, we monitored colonization by these two fungi in the kernel. Visible colonization of the kernel was evident at 48 hours post inoculation (hpi) and both fungi reached the germ by 72 hpi, but colonization patterns by the two fungi differed. We also analyzed transcriptome changes of kernels during infection by these two fungi at 24, 48, and 72 hpi using RNA sequencing (RNA-seq). The results show that a set of defense- related genes was associated with both pathosystems, indicating a conserved response to fungal infection. Pathway analysis revealed that the signaling network regulated by plant hormones played an important role in shaping maize responses to these two pathogens. Of the known plant defense pathways, genes in the jasmonic acid (JA) and ethylene (ET) pathways appeared to be the most highly expressed during infection by both fungi. Infection by these two fungi also induced other changes in primary and secondary metabolism
263 Read more
Fusarium verticillioides reduces corn yield and contaminates infected kernels with the toxin fumonisin, which is harmful to humans and animals. Previous research has demonstrated that F. verticillioides can be controlled by the azole fungi- cide prochloraz. Currently, prochloraz is used as a foliar spray to control maize disease in China, which will increase the risk of resistance. Although F. verticillioides resistance to prochloraz has not been reported in the field, possible resis- tance risk and mechanisms resulting in prochloraz resistance were explored in the laboratory. Four prochloraz-resistant strains of F. verticillioides were generated by successive selection on fungicide-amended media. The mycelial growth rates of the mutants were inversely related to the level of resistance. All four mutants were cross-resistant to the triazole fungicides triadimefon, tebuconazole and difenoconazole, but not to the multisite fungicide chlorothalonil or to the MAP/histidine-kinase inhibitor fungicide fludioxonil. Based on the Y123H mutation in FvCYP51B, the four resistant mutants were subdivided into two genotypes: PCZ-R1 mutants with wildtype FvCYP51B and PCZ-R2 mutants with substitution Y123H in FvCYP51B. Wildtype FvCYP51B complemented the function of native ScCYP51 in Saccharomy- ces cerevisiae YUG37::erg11, whereas Y123H-mutated FvCYP51B did not. For the PCZ-R1 mutants, induced expression of FvCYP51A increased resistance to prochloraz. For the PCZ-R2 mutants, disruption of FvCYP51B function by the Y123H substitution caused constitutive up-regulation of FvCYP51A expression and thus resistance to prochloraz.
10 Read more
In filamentous fungi, the GATA-type transcription factor AreA plays a major role in the transcriptional activation of genes needed to utilize poor nitrogen sources. In Fusarium fujikuroi, AreA also controls genes involved in the biosynthesis of gibberellins, a family of diterpenoid plant hormones. To identify more genes responding to nitrogen limitation or sufficiency in an AreA-dependent or -independent manner, we examined changes in gene expression of F. fujikuroi wild-type and ⌬ areA strains by use of a Fusarium verticillioides microarray representing ⬃ 9,300 genes. Analysis of the array data revealed sets of genes significantly down- and upregulated in the areA mutant under both N starvation and N-sufficient conditions. Among the downregulated genes are those involved in nitrogen metabolism, e.g., those encoding glutamine synthetase and nitrogen permeases, but also those involved in secondary metabolism. Besides AreA-dependent genes, we found an even larger set of genes responding to N starvation and N-sufficient conditions in an AreA-independent manner. To study the impact of NMR on AreA activity, we examined the expression of several AreA target genes in the wild type and in areA and nmr deletion and overexpression mutants. We show that NMR interacts with AreA as expected but affects gene expression only in early growth stages. This is the first report on genome-wide expression studies examining the influence of AreA on nitrogen-responsive gene expression in a genome-wide manner in filamentous fungi.
16 Read more
According to Braun (2007), maize (Zea mays L.) is a staple food for the majority of the world’s population as well as wheat and rice. This important food source can be infested by mycotoxin produced by Fusarium spp. Fusarium verticillioides (synonym: F. moniliforme) belongs to a large genus of filamentous fungi which is prevalent in the midwestern and southeastern United States with some species producing mycotoxins in cereal crops that can affect human and animal. F. proliferatum, a closely related fungus also occurs regularly and has been isolated from infected maize (Abbas et al., 2002). These species produce high levels of fumonisin (Leslie, 1991, 2004); even in plants that do not show symptoms of infestation.
Etcheverry et al.  demonstrated the potential bio- control agents M. oleovorans and B. amyloliquefaciens influenced the growth rate and increased the lag phase of F. verticillioides strains assayed in vitro at different water activities. In this study we obtained a similar result, con- sequently we can infer that the physiological adaptation leaving a clear unaffected biocontrol potential, by con- trary the reduction effect on the growth rate of F. verticil- lioides was higher with cells previously adapted to low water activities.
There is a great interest in applying RNAi to patho- genic fungi. Specific inhibition of gene expression by RNAi has been shown to be suitable for a multitude of phytopathogenic filamentous fungi, such as Magna- porthe oryzae , Sclerotinia sclerotiorum , Phy- tophthora sojae , Aspergillus nidulans , A. fumigatus [25-28], A. oryzae , Bipolaris oryzae , Colletotrichum lagenarium , Coprinus cinereus [32,33], Fusarium solani , Mucor circinelloides , which were transformed with plasmid constructs to express self-complementary hairpin RNA molecules . It has also been shown that simply adding syn- thetic siRNA molecules to the culture medium can result in specific suppression of the corresponding target gene in Aspergillus nidulans . In addition, the repor- ter gfp transgene and the endogenous genes coding for hydrophobins and a peroxiredoxin were silenced in Moniliophthora perniciosa transfected with in vitro synthesized specific dsRNA . However, the dsRNA/ siRNA silencing effect has not been observed in vivo. Here we show that the gus gene expression can be spe- cifically silenced in Fusarium verticillioides (= F. monili- forme) interacting with a transgenic plant engineered with a gus gene-inferring cassette [hairpin (hp)GUS].
11 Read more
The most frequent species causing fusariosis are Fusarium solani, Fusarium oxysporum, and Fusarium verticillioides (1, 16, 47), but several other species are also found to cause human infections, although less frequently. Some of these species are Fusarium chlamydosporum, Fusarium dimerum, Fusarium incarnatum, and the following other species that are included into the Gibberella fujikuroi species complex: Fusarium napiforme, Fusarium nygamai, Fusarium prolifera- tum, and Fusarium sacchari (30, 31). These species have been associated with different types of infection, in partic- ular with keratomycoses and other ocular infections (10) and with disseminated infections in immunocompromised patients (2, 6, 17, 20, 23, 24, 26, 39, 41, 43, 44). The real incidence of these species is unknown since they are poorly known and laboratorians and clinical microbiologists are not generally aware of their possible presence in human infec- tions.
A total of 300 one day old quail chicks (Coturnix coturnix japonica) were divided into 4 groups (3 replicates per teatment), viz. control (CX), fumonisin B 1 (FX), ochratoxin A (OX) and combination (FO) containing 75 birds in each group. Birds in the control group (CX) were fed quail mash alone, where as birds in group FX were fed 200 ppm of fumonisin B 1 (FB 1 ) from Fusarium verticillioides culture material; group OX was fed 2 ppm of ochratoxin A from Aspergillus ochraceous NRRL-3174; and group FO was fed a combination of 200 ppm of FB 1 and 2 ppm of OTA. Diets were fed from day 1 to 28 to study serum biochemistry. Birds in general showed anorexia, dullness, diarrhoea, depression in body weight, poor feathering and incoordinated movements. Significantly increased serum creatinine and uric acid values were observed in our study.
Fusarium oxysporum f. sp. Lycopersici was identified in the surveyed region and causes vascular wilt in tomatoes in the coastal region. Farmers use susceptible cultivars has aggravated the problem hence the use of resistant cultivars could be successful in decreasing the vascular wilt. Fusarium wilt, the disease is controlled by preventing introduction of the pathogen, destruction of the diseased plant and isolation of susceptible plants from the infested site (Simone and Cashion, 1996). Resistant tomato and melons cultivars have been successful in conferring resistance to races of F. oxysporum f.sp. lycopersici and F. oxysporum f.sp. melonis respectively (Joobeur et al., 2004). Tomato cultivation in the coastal region has encouraged the multiplication of F. oxysporum f.sp. lycopersici in the coastal region due to the substate produced by tomato. Husain and Dimond (1960) reported that the action of cellulase produced by the tomato wilt pathogen F. oxysporum f.sp. lycopersici may be conceived to act in pathogenesis in three ways. Firstly, it is involved in wilt induction. In addition, hydrolytic products of cellulase activity may provide Fusarium with carbohydrates for its continued development in the host, and thirdly, it is involved in the escape of the pathogen from vascular tissue in advanced stages of disease when the host is in dying condition.
133 Read more
Three plant species namely Vernonia polysphaera, Syzygium aromaticum, and Allium sativum effectively inhibited the mycelia growth and conidial germination of Cercospora coffeicola, Colletotrichum gloeosporioides, Fusarium oxysforum, Phoma tarda, Rhizoctonia solani, and Hemileia vastatrix . Ethanol and acetone extract of leaves of nine medicinal plants namely Piper betel, Lowsonia inermis, Psidium guajava, Carica papaya, Moringa oleifera, Mimosa pudica, Cathanthus roseus, Adhatoda vasica, and Andrographis paniculata were tested for their inhibitory activities against Fusarium oxysforum the causal agent of Fusarium wilt in tomato . Among them, ethanol extracts of two plants viz. Lowsonia inermis, and Psidium guajava showed superior inhibitory activity (100%) at concentration 15%.
13 Read more