**2.2. Trichothecenes**

and contamination to diverse types of cereals mainly to maize being of toxicological concern the ear rot [2]. Therefore, the contamination prevention could be generated by the biosynthesis the *Fusarium* during the crop. Then, the development of *Fusarium* can be triggered by the environmental conditions, agricultural practices and range of susceptibility [3]. Biochemical resistance is directly associated with specific proteins and metabolites that focus on the biosynthetic analysis of mycotoxins explaining the sporadic occurrence of the mycotoxins as fungal metabolites. Several studies indicate that secondary metabolites present in cereals can modulate the production of mycotoxins, and these are important in plant response to fungal contaminations, such as, the phenolic compounds that control or prevent the response to mycotoxins [4]. Phenolic acids, including ferulic acid, tannins and proanthocyanidins, are the most abundant in cereal showing the highest potential to function as fungal growth inhibitor [1, 3]. In this sense, the objective of this chapter is the review of the main mycotoxins of the genus *Fusarium* that affects cereals, as well as the production of secondary metabolites that can modulate their production. The above will gather relevant information on possible inhibition options in cereal contamination by mycotoxins of the genus *Fusarium*, including major mycotoxin-producing species, cereal contamination by mycotoxins (economic losses, implications to food safety and health), cereal secondary metabolites with antifungal activity and possible mechanisms that

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

The genus *Fusarium* comprises an outsize cluster that includes animal and plant pathogenic species with great biological properties [5]. Some species are used as biocontrol agents, as industrially applicable enzymes, and some cause diseases in many agronomical crops and are probably the most prevalent toxin-producing fungi [6]. The genera *Aspergillus*, *Penicillium* and *Fusarium* are filamentous fungi and produce mycotoxins that are toxic and/or carcinogenic secondary metabolites produced under appropriate environmental conditions [7]. *Fusarium* produces three of the most important of mycotoxins, such as *fumonisins*, *trichothecenes* or *zearalenone*, and these furthermore produce emerging mycotoxins as well as *fusaproliferin*, *beauveri-*

Mycotoxins possess biological activities that represent a problem for both human and animal health (**Figure 1**). The ingestion of these compounds can cause chronic disease, morbidity and death and reduce the resistance to pathogens [9]. Most mycotoxin are stable during food processing, and these are commonly resistant to chemical and thermal changes. Mycotoxins

Aflatoxins (B1, B2, G1, G2) are difuranocoumarin synthesized by *Aspergillus flavus* and *Aspergillus parasiticus* present in soil and various organic materials. Aflatoxin-producing species has been reported in a wide variety of food commodities (maize, peanuts, barley oats, rice, cottonseed, spices and figs [12]. Optimal conditions for their propagation are high temperature

modulate inhibition of mycotoxin production of *Fusarium* species.

**2. Overview of major mycotoxin-producing species**

can also come to the human by animal products [10, 11].

*cin*, *enniatins* and *moniliformin* [8].

**2.1. Aflatoxins**

Trichothecenes can be divided into four types: A (T-2 and HT-2 toxins, diacetoxyscirpenol), B (deoxynivalenol, nivalenol), C and D, and these are the main and most diverse chemical groups of the three major classes of *Fusarium* mycotoxins [14, 15]. These are shaped by a set sesquiterpenoids with or without a tricyclic nucleus. Trichothecenes are small, amphipathic molecules that can move passively across cell membranes [16, 17]. The most prevalent contaminants in wheat, barley, oats and maize are trichothecenes of types A and B. Exposure to these toxins can cause immunological problems, vomiting, skin dermatitis, hemorrhagic lesions, acute diseases and gastroenteritis. Trichothecenes in wheat behaves as phytotoxic were causing chlorosis, inhibition of root elongation, and dwarfism [4, 9]. Trichothecenes show several inhibitory effects such as inhibition of proteins, DNA and RNA synthesis on the primary metabolism of eukaryotic cells [18].
