Antioxidant Secondary Metabolites in Cereals: Potential Involvement in Resistance to Fusarium and Mycotoxin Accumulation

Abstract

Gibberella and Fusarium Ear Rot and Fusarium Head Blight are major diseases affecting European cereals. These diseases are mainly caused by fungi of the Fusarium genus, primarily Fusarium graminearum and Fusarium verticillioides. These Fusarium species pose a serious threat to food safety because of their ability to produce a wide range of mycotoxins, including type B trichothecenes and fumonisins. Many factors such as environmental, agronomic or genetic ones may contribute to high levels of accumulation of mycotoxins in the grain and there is an urgent need to implement efficient and sustainable management strategies to reduce mycotoxin contamination. Actually, fungicides are not fully efficient to control the mycotoxin risk. In addition, because of harmful effects on human health and environment, their use should be seriously restricted in the near future. To durably solve the problem of mycotoxin accumulation, the breeding of tolerant genotypes is one of the most promising strategies for cereals. A deeper understanding of the molecular mechanisms of plant resistance to both Fusarium and mycotoxin contamination will shed light on plant-pathogen interactions and provide relevant information for improving breeding programs. Resistance to Fusarium depends on the plant ability in preventing initial infection and containing the development of the toxigenic fungi while resistance to mycotoxin contamination is also related to the capacity of plant tissues in reducing mycotoxin accumulation. This capacity can result from two mechanisms: metabolic transformation of the toxin into less toxic compounds and inhibition of toxin biosynthesis. This last mechanism involves host metabolites able to interfere with mycotoxin biosynthesis. This review aims at gathering the latest scientific advances that support the contribution of grain antioxidant secondary metabolites to the mechanisms of plant resistance to Fusarium and mycotoxin accumulation.

Rising atmospheric CO2 concentration may imply higher risk of Fusarium mycotoxin contamination of wheat grains

“…Highly increased ZEN concentrations at elevated CO2, however, could not be associated with the number of dead spikelets. Plant resistance to Fusarium and mycotoxin production is a highly complex mechanism, including also antioxidant secondary metabolites, which can be toxic to the fungi, participate in cell wall reinforcement as well as interfere with toxin biosynthesis (Atanasova-Penichon et al 2016). Fast activation of the antioxidant defence system was also matched with better resistance levels of plants (Khaledi et al 2016, Spanic et al 2017.…”

Metabolic profiling of wheat rachis node infection by Fusarium graminearum – decoding deoxynivalenol‐dependent susceptibility

“…Phenylalanine is the direct precursor of cinnamic acid and p-coumaric acid, respectively. Interestingly, cinnamic acid and p-coumaric acid are potent inhibitors of trichothecene biosynthesis (Atanasova-Penichon et al, 2016). The activation of the phenylpropanoid pathway is well described during pathogen infection (Divon & Fluhr, 2007;H€ uckelhoven, 2007).…”

Showcasing the application of synchrotron‐based X‐ray computed tomography in host–pathogen interactions: The role of wheat rachilla and rachis nodes in Type‐II resistance to Fusarium graminearum

“…Some studies suggest cell‐wall lignification to be an important component of FHB resistance in moderately resistant wheat genotypes and have concluded that FTIR‐based markers can be used to differentiate genotypes (Atanasova‐Penichon et al, ; Gunnaiah & Kushalappa, ; Lahlali et al, ; Lahlali et al, ). In contrast, our study did not find any consistent results for some important bipolymeric compounds such as cellulose, pectin, and xylan.…”

“…Earlier, histopathology studies were mostly aimed at understanding the host–pathogen interaction and pathogen infection processes (Anderson, ; Arthur, ; Atanasoff, ; Brown et al, ; Jansen et al, ; Kang & Buchenauer, ; Miller et al, ; Pugh et al, ; Ribichich et al, ). More recent studies have focussed on metabolomics, proteome, or gene expression profiling of the host–pathogen interaction (Gunnaiah & Kushalappa, ; Atanasova‐Penichon, Barreau, & Richard‐Forget, ; reviewed in Kazan, Gardiner, & Manners, ; Shah et al, ). A large number of candidate genes in resistant cultivars are associated with the phenotypic expression and temporal and spatial profiling of the genes.…”