Fusarium

A genus of fungus, also known as “scab,” that infests certain grains (e.g., wheat Triticum aestivum, com or maize Zea mays L., etc.) during growing seasons in which climate (e.g., high humidity, cool weather) and other conditions combine to enable rapid growth/proliferation of the fungus. In wheat, (fusarium head blight) fungus infestation causes the wheat plant to weaken and to produce empty seed heads, which reduces yield.

As a by-product of its metabolism, fusarium produces fumonisins (one of which is known as DON or “vomitoxin”), a group of mycotoxins. Fumonisin B1 is the most prevalent fusarium-produced mycotoxin in com (maize). Its presence can cause livestock to refuse to eat infested feed, decrease reproductive efficiency in swine, and even kill horses (via equine leukoencephalomalacia).

When consumed by humans, fumonisin B1 induces cell death via apoptosis; and the tissues that are adjacent to killed cells respond with cell replication/proliferation to replace the lost cells. Fumonisin B1 inhibits the enzyme ceramide synthetase (which is crucial to the biosynthetic pathway for the creation of sphingolipids in cells), resulting in accumulation of sphinganine in cells, and decreases ceramides and complex sphingolipids. These internal changes signal the cells to die via apoptosis (“programmed cell death”), especially liver and kidney cells.

Maximum fumonisin content allowed in flour (for U.S. bread) is one part per million. Maximum fumonisin content allowed in U.S. malting barley (Hordeum vulgare) is zero. In 1997, Iowa State University research showed that B.t. com varieties (which express the B.t. protoxin in the com ears) have significantly less ear mold caused by Fusarium fungi. That is because the European com
borer (ECB) is a vector (carrier) of Fusarium.

A genus of fungi, most of which are plant pathogens, and a few of which may be opportunistic in humans.