Welcome back to our Mycotoxin Series!
With wheat harvest mostly complete for the eastern United States, it only seems fitting that I write about deoxynivalenol (DON). DON is produced by Fusarium graminearum (amongst others) and can be found in products made with wheat, barley and corn. DON has been dubbed the “most commonly encountered” mycotoxin. This is likely due to our diets (wheat and corn are staple crops in many cultures and are used in many food products) and much of the wheat we grow is rather susceptible to F. graminearum.
F. graminearum is the causal agent of Fusarium head blight of small grains (also known as Scab). The disease is characterized by premature “bleaching” of the wheat heads (see above), shriveled kernels, reduced yield and DON contamination. F. graminearum also causes a disease in corn called Gibberella ear rot (more of a concern for livestock). DON serves as a virulence factor for F. graminearum which means DON is a powerful “weapon” for this pathogen as it infects the plant.
DON is a mycotoxin that is harmful to both plants and animals (any eukaryotic cell, for that matter). DON binds to ribosomes, preventing cells from translating genes to proteins (remember, Bio 101: DNA –> mRNA –> amino acids/proteins). Without essential proteins, cells are unable to carryout basic function and die (e.g. bleached, dead tissue on wheat heads).
DON is also known as “vomitoxin”. This gives you a pretty specific idea about what sort of symptoms we observe in humans and animals suffering from DON poisoning. DON may also cause other gastro-intestinal distress, poor nutrient absorption, reduced weight gain, feed refusal and impaired immunity. Despite being the most commonly encountered mycotoxin, we don’t have a good handle on the effects of chronic exposure to low doses of DON that may be in our breakfast cereals, breads, pretzels, pastas, etc.
PS – A fact sheet I co-wrote on DON in corn in Ohio