**4.1. Phenylpropanoids**

by deoxynivalenol added the ribosome in eukaryotic cells [20]. The impact of deoxynivalenol on the immune system ranges from immunosuppression to immunostimulation, according to its

Nivalenol are the main mycotoxins produced by *F. cerealis*, *F. poae*, *F. nivale*, *F. culmorum* and *F. graminearum*. Maize red ear rot throughout is caused by nivalenol [21]. As expected, they reportedly also share many toxicological properties, such as the inhibition of cell proliferation, induction of interleukin-8 secretion and the involvement of stress-activated MAPKs and

Zearalenone is a mycotoxin, which have a structure of estrogenic lactone; they have sufficient structural similarity and these synthesized by various *Fusarium* species—*F. graminearum*, *F. culmorum* and *F. crookwellense*. Zearalenone is found in cereals, mainly maize, and processed foods and these are a non-highly toxic mycotoxin [10, 22]. These mycotoxins have been producing of estrogenic effects in animals and the stimulation of human breast cancer cells growth. Zearalenone is a mycotoxin producing of host-contaminated corn [9]. Also, inhibiting the gene expression caused by zearalenone produced severe hepatic illness. Zearalenone has been shown to be immunotoxin

*Fusarium verticillioides* and *F. moniliforme* produced by Fumonisins (A, B, C, P) are toxic secondary metabolites, mycotoxins non-fluorescent, common fungal contaminants in grains and agricultural commodities [24]. These are analogous to sphingolipids, and intake of contaminated foods with fumonisins B1 has been associated with equine leukoencephalomalacia, porcine pulmonary edema and liver cancer in rats and decreased body weights in chickens [8, 23]. The exposure levels ranging from 0.02 to 0.2 mg/kg in body weight have been found of fumonisin concentration; these are within the limit of intake. Although fumonisins are relatively thermal stability, these may undergo reactions in food systems that alter their chemical structure and

Mycotoxin contamination can occur pre-harvest when the crop plant is growing or postharvest during processing. Storage of cereals at temperatures over 37°C increases humidity during prolonged storage times is a factor for crops and cereals to be susceptible to mold growth and mycotoxin contamination [16]. The susceptibility of the grain is another factor to consider, presenting greater susceptibility maize and lower rice. Animal pests, weeds and pathogens impact yield and quality of cereals. *F. graminearum* mostly affects cereals, including maize, wheat and barley. The predominant *Fusarium* species associated with ear and stalk

nuclear factor-κΒ in the signal transduction pathways of toxicities [15].

26 Fusarium - Plant Diseases, Pathogen Diversity, Genetic Diversity, Resistance and Molecular Markers

and hepatotoxic and nephrotoxic and an enhancer of lipid peroxidation [19, 23].

toxicity and is potentially hazardous to the health of both humans and animals [25].

**3. Overview of mycotoxin-contaminating cereals**

concentration, duration and time of exposure [19].

**2.4. Nivalenol**

**2.5. Zearalenone**

**2.6. Fumonisins**

Phenolic compounds are secondary metabolites that are produced by descend from the phenylpropanoid pathway and are synthesized by plants from the amino acid phenylalanine. Plant biosynthesis produces various phenols that can be grouped commonly as flavonoids and phenolics. Flavones, flavonols, flavanones, flavan-3-ols, anthocyanidins, isoflavones, coumarins, stilbenes and lignans are the main flavonoids. These are structurally distinct because of their specific hydroxylation, methylation and conjugation patterns, with various monosaccharides and disaccharides. Phenolic acids found in cereals exist in both soluble (free) and insoluble

lemmas and paleas of the spring cultivar concluding that phenolic compounds appear to play a role in the resistance of the cultivars to *F. culmorum* [35]. In the same way, a study with date palm roots showed that date palm roots contain four cell wall-bound phenolics identified as *p*-hydroxybenzoic acid, *p*-coumaric acid, ferulic acid and sinapic acid. The contents of *p*-coumaric acid and ferulic acid, *p*-hydroxybenzoic acid, sinapic acid and lignin in the resistant cultivars to *F. oxysporum* were about 2, 8.4, 4.5 and 1.8 times higher than those in the

*Fusarium* Mycotoxins and Metabolites that Modulate Their Production

http://dx.doi.org/10.5772/intechopen.72874

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Regarding mycotoxin production, cinnamic acid derivatives such as sinapic, caffeic, *p*-coumaric, chlorogenic and ferulic acids are efficient inhibitors of TCTB (type B trichothecenes) production by *F. graminearum* and *F. culmorum.* It is important to mention that the effect of

An amount of studies support that phenolic compounds have a role in enhanced plant resistance to *Fusarium* [38–43]. Besides, number of studies related to phenolic acids supports that in cereals, cell wall-bound ferulic acid along with its dehydrodimers and free chlorogenic acid

Terpenes are the most numerous and structurally diverse plant natural products. The plethora of terpenoid compounds is biosynthetically assembled from only two simple precursors, isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP). Plant terpenoids include compounds ranging from C5 hemisesquiterpenes to C40 tetraterpenes, with diverse physical and chemical properties leading to lipophilic or hydrophilic, volatile or non-volatile metabolites [44].

Several terpenoids have their roles in plant defense against biotic and abiotic stresses, or they are treated as signal molecules to attract the insects of pollination. In a study using cyclic terpenes (limonene, menthol, menthone and thymol) against *F. verticillioides*, limonene and thymol showed the highest inhibitory effects on *F. verticillioides* development. Thymol was the

In the last year, essential oils, which composition mainly include terpenes and terpenoids, from different plants were used in the prevention of fungi and mycotoxins accumulation in cereals. A study using *Melissa officinalis*, *Salvia officinalis*, *Coriandrum sativum*, *Thymus vulgaris*, *Mentha piperita* and *Cinnamomum zeylanicum* showed that all these essential oils have an inhibitory effect on fungal contamination of wheat seeds. This ability was dose-dependent. Regarding mycotoxin development, the best control on fumonisins production was recorded for *Cinnamomum zeylanicum* [46]. Similar findings regarding essential oils were done by Daferera et al. [47]; *Fusarium* sp. was completely inhibited by oregano, thyme, dictamnus and marjoram essential oils at moderately low concentrations (85–300 μg/mL). Also, oils from *Cymbopogon citratus*, *Ocimum basilicum* and *Ocimum gratissimum* were the most effective *in vitro*, completely inhibiting the growth of *F. verticillioides*. The application of these oils at concentrations of 8, 6.4 and 4.8 μL/g inhibit the growth of *F. verticillioides* in maize for a period of 21 days. It was also observed that the production of fumonisin was not affected by the lower concentration (4.8 μL/g) [48].

could be pivotal components of the resistance to toxigenic *Fusarium* species [34].

phenolic compounds is strain and molecule dependent [37].

most active inhibitor of fumonisin B1 biosynthesis [45].

susceptible cultivars [36].

**4.2. Terpenoids**

**Figure 2.** Cereal secondary metabolites with antifungal activity.

(cell wall-bound) forms [31]. The major portion of phenolic compounds is in the outer part of grains. Moreover, phenolic acids, predominantly ferulic and coumaric acid, play an important role in limiting polysaccharide degradation by exogenous enzymes, where they act as a cross-link between polysaccharides and between polysaccharides and lignin [32].

Phenolic compounds in plants are involved in the interaction between the pathogen and the plant. For example, the phenolic acids accumulated throughout the development of wheatkernel development impact positively the resistance to *Fusarium* [33]. It has been reported the fungicidal efficiency of phenolic compound considering IC50 values. These values rank between 0.7 and >10 mM [30].

It has been stated that the most maize-resistant genotypes exhibited high levels of phenylpropanoids, which were related to low levels of disease severity and grain fumonisin (FUMO) concentration [34]. In a study using wheat cultivars (winter and spring), significantly higher amounts of free phenolic compounds were found in the glumes, lemmas and paleas of the spring cultivar prior to and at all sampling times after inoculation, in comparison to the winter wheat cultivar. The spring cultivar exhibited resistance against initial infection by the fungus. It was found that the amount of *p*-coumaric acid increased significantly in the glumes, lemmas and paleas of the spring cultivar concluding that phenolic compounds appear to play a role in the resistance of the cultivars to *F. culmorum* [35]. In the same way, a study with date palm roots showed that date palm roots contain four cell wall-bound phenolics identified as *p*-hydroxybenzoic acid, *p*-coumaric acid, ferulic acid and sinapic acid. The contents of *p*-coumaric acid and ferulic acid, *p*-hydroxybenzoic acid, sinapic acid and lignin in the resistant cultivars to *F. oxysporum* were about 2, 8.4, 4.5 and 1.8 times higher than those in the susceptible cultivars [36].

Regarding mycotoxin production, cinnamic acid derivatives such as sinapic, caffeic, *p*-coumaric, chlorogenic and ferulic acids are efficient inhibitors of TCTB (type B trichothecenes) production by *F. graminearum* and *F. culmorum.* It is important to mention that the effect of phenolic compounds is strain and molecule dependent [37].

An amount of studies support that phenolic compounds have a role in enhanced plant resistance to *Fusarium* [38–43]. Besides, number of studies related to phenolic acids supports that in cereals, cell wall-bound ferulic acid along with its dehydrodimers and free chlorogenic acid could be pivotal components of the resistance to toxigenic *Fusarium* species [34].
