Carotenoids Occurring in Maize Affect the Redox Homeostasis of Fusarium graminearum and Its Production of Type B Trichothecene Mycotoxins: New Insights Supporting Their Role in Maize Resistance to Giberella Ear Rot

Abstract

Fusarium graminearum is the causal agent of Gibberella ear rot (GER) in maize, a devastating fungal disease resulting in yield reduction and contamination of grains with type B trichothecene (TCTB) mycotoxins. Reducing GER damage requires the implementation of an integrated management strategy in which the use of resistant maize genotypes is a key factor. The present study aimed at providing new phenotyping tools to improve breeding pipelines by investigating the yet understudied contribution of carotenoids to GER resistance. Here, we demonstrated for the first time the efficiency of carotenoid extracts from various maize genotypes to inhibit the production of TCTB by F. graminearum. We further suggested that zeaxanthin could be a key actor of this inhibition efficiency, notably via a negative transcriptional control of several biosynthetic genes of the TCTB pathway. Besides, we demonstrated that zeaxanthin treatments led to profound perturbations in the fungal redox homeostasis by affecting the expression of key genes encoding ROS detoxifying enzymes, several of them being involved in F. graminearum virulence during plant infection. Altogether, our data support the contribution of carotenoids to the mechanisms employed by maize to counteract F. graminearum infection and its production of TCTB.

Advances in Genetic Enhancement of Nutritional Quality of Tropical Maize in West and Central Africa

“…Understanding the interactions between the genetic factors governing nutritional and antinutritional traits is valuable for precise and simultaneous genetic manipulations to expand the double benefit from both traits. A recent report showed that carotenoid extracts from various maize genotypes could efficiently inhibit the production of certain mycotoxins [35]. To efficiently exploit such unintended benefits from increased carotenoids in maize genotypes, understanding the underlying genetic mechanisms conditioning the desirable association of the two traits is critical.…”

Genetics and Environmental Factors Associated with Resistance to Fusarium graminearum, the Causal Agent of Gibberella Ear Rot in Maize

“…Other important compounds effective against fungal infection are carotenoids. In corn, zeaxanthin has been demonstrated to be effective in the inhibition of DON production due to its effect on the DON biosynthetic pathway [140]. Physical defenses are another type of resistance, and the two major characteristics in maize correlated with the reduction in GER damage are husk tightness and ear attitude.…”

Investigating Metabolic Plant Response toward Deoxynivalenol Accumulation in Four Winter Cereals

“…8,11−15 Following a comparative approach, many studies have pointed out a wide spectrum of primary and secondary metabolites whose production differs in resistant and susceptible cultivars or that are differently accumulated upon Fusarium infection in the field. 14,16,17 Many reports support for instance the involvement of phenylpropanoids and phenols such as alkylresorcinols (ARs) in plant resistance to fungal pathogens, 18 which mainly results from their antimicrobial properties, their key role as plant defense mediators and their participation to cell wall reinforcement. Similarly, soluble and cell-wall bound phenolic acids have been described as involved in cell-thickening processes following pathogen insult.…”

“…Together with genomics and transcriptomics studies, metabolomics has recently emerged as a technique of election for diving into such genetic pools and to explore plant adaptation to biotic and abiotic stresses. − It is indeed recognized that a large set of constitutive as well as inducible defense metabolites could play a pivotal role in the resistance of cereals against pathogenic fungi. ,− Following a comparative approach, many studies have pointed out a wide spectrum of primary and secondary metabolites whose production differs in resistant and susceptible cultivars or that are differently accumulated upon Fusarium infection in the field. ,, …”