**6. Fungal resistance**

Shi et al. [5] evaluated the mycotoxins from 20 of the most common *Fusarium* species and sorted them into the following three groups based on their molecular characterization (**Figure 2**). Group-1 comprised fusaric acid producers and was further divided into two subgroups. Subgroup-I comprised *F. fujikuroi*, *F. solani*, *F. verticillioides* and *F. proliferatum* that produce fusaric acid and fumonisins; subgroup-II comprised *F. musae*, *F. equiseti*, *F. temperatum*, *F. subglutinans*, *F. tricinctum*, *F. oxysporum*, *F. concentricum*, *F. sacchari* and *F. andiyazi* that produce only fusaric acid. According to the classification of *Fusarium* mycotoxins, type-A trichothecene producers comprising *F. polyphialidicum*, *F. sporotrichioides* and *F. langsethiae* formed the Group-II, and type-B trichothecene producers comprising *F. meridionale*, *F. culmorum*,

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

In the presence of *Fusarium* species in plants, the contamination with fumonisins was shown in wheat [26], garlic [27], and asparagus [28]. The most affected plants, that is, maize, beans, soybean [29], rice [30], and sorghum [31] were specifically infected by *Gibberella fujikuroi* spe-

Guidance values for *Fusarium* mycotoxins were set in Commission Recommendation 2006/576/ EC [33]. Recommended values for the *Fusarium* mycotoxins DON, ZEA and fumonisins were set in "Commission Recommendation 2006/576/EC" [33]. For T-2 and HT-2 toxin, indicative

**Figure 1.** Worldwide mycotoxin occurrence (μg/kg) in maize and wheat/bran samples (A, C: Median of positive samples;

*F. graminearum* and *F. poae* formed Group-III.

B, D: Maximum levels) [24, 25].

cies complex (*F. proliferatum, F. verticillioides* and *F. andiyazi*) [29, 32].

Resistance of *Fusarium* to antifungal drugs has been defined by many researchers. It is known that many FSSC members cause fusarial onychomycosis [36]. *F. solani* showed more resistance to antifungal agents than others [37]. The effect of azole antifungals used clinically is depend on a particular site, lanosterol-14α-demethylase. While imidazole or triazole rings are important for conferring the therapeutic effect in animals, epoxiconazole, propiconazole, difenoconazole, bromuconazole and tebuconazole are used for plants. *Fusarium* spp. are resistant to azoles [38].

Tupaki-Sreepurna et al. [39] reported that FSSC members, mainly *F. falciforme* and *F. keratoplasticum*, showed multi-drug resistance against caspofungin and azoles. Only a few antifungal agents (voriconazole, posaconazole and amphotericin B) showed *in-vitro* activity against *F. falciforme* and *F. keratoplasticum* [40].

Conversely, the echinocandins are lipopeptide molecules which effectively work by inhibiting 1,3-β-D-glucan synthase of the fungal membrane. If a change occurs in the amino acid residues of β-1,3-glucan synthase enzyme subunits (FKS subunits) in the treatment process, it may lead to increased drug resistance [41, 42].

Polyenes, which are fungicidal, are known as amphipathic drugs, such as nystatin and amphotericin-B. The complexes show efficacy via destroying the proton gradient, allowing for the leakage of ions and removal of ergosterol from phospholipids in the membrane, thus causing fungal cell death in the process [43, 44].

species level is not easy. Therefore, molecular methods are needed. Some of the most commonly used molecular methods are the genus-specific PCR, 28 s rRNA gene sequencing, sequencebased PCR, multiplex tandem PCR and automated repetitive sequence-based PCR [54].

Introductory Chapter: *Fusarium* - Pathogenicity, Infections, Diseases, Mycotoxins and Management

http://dx.doi.org/10.5772/intechopen.76507

7

As a biological control, Ben Amira et al. [55] showed that when *Trichoderma harzianum* was co-cultured with *F. solani*, the former happened to have an antagonistic effect *in-vitro*. Then, they repeated this experiment by inoculating olive tree roots with the same *T. harzianum* and *F.* solani combination. They reported that the former showed a mycoparasitic reaction and antagonistic effects on *F. solani*. Therefore, mycoparasitic fungi, such as *T. harzianum* may be

Notably, agricultural and chemical precautions cannot be completely successful in preventing *Fusarium-*related diseases in plants [56]. Therefore, synthetic fungicides are not a true approach for preventing the *Fusarium*-related diseases due to their harmful effects on the ecosystem and environment, and growing disease-resistant species to combat *Fusarium-*related diseases seems a more sustainable approach. Resolving the concern of plant diseases caused by *Fusarium* using biological control methods seems to be a more efficient and eco-friendly

Faculty of Sciences and Arts, Department of Biology, University of Balikesir, Balikesir,

[1] Lamprecht SC, Tewoldemedhin YT, Botha WJ, Calitz FJ. *Fusarium graminearum* species complex associated with maize crowns and roots in the KwaZulu-Natal Province of

[2] Chetouhi C, Bonhomme L, Lasserre-Zuber P, Cambon F, Pelletier S, Renou JP, et al. Transcriptome dynamics of a susceptible wheat upon *Fusarium* head blight reveals that molecular responses to *Fusarium graminearum* infection fit over the grain development processes. Functional & Integrative Genomics. 2016;**16**:183-201. DOI: 10.1007/

[3] McMullen M, Bergstrom G, De Wolf E, Dill-macky R, Hershman D, Shaner G, et al. Fusarium head blight disease cycle, symptoms, and impact on grain yield and quality frequency and magnitude of epidemics since 1997. Plant Disease. 2012;**96**:1712-1728.

South Africa. Plant Disease. 2011;**95**:1153-1158. DOI: 10.1094/PDIS-02-11-0083

used as a biocontrol agent against *Fusarium*.

approach for agricultural products.

Address all correspondence to: taskun@balikesir.edu.tr

**Author details**

Tulin Askun

**References**

s10142-016-0476-1

DOI: 10.1094/PDIS-03-12-0291-FE©

Turkey
