Reducing production of fumonisin mycotoxins in Fusarium verticillioides by RNA interference

AbstractThe fungusFusarium verticillioides is a maize pathogen that can produce fumonisin mycotoxins in ears under certain environmental conditions. Because fumonisins pose health risks to humans and livestock, control strategies with minimal risk to the environment are needed to reduce fumonisin contamination. Host-induced gene silencing is a promising technique in which double-stranded RNA expressed in the plant host is absorbed by an invading fungus and down-regulates genes critical for pathogenicity or mycotoxin production in the fungus. A key preliminary step of this technique is identification of DNA segments within the targeted fungal gene that can effectively silence the gene. Here, we used segments of the fumonisin biosynthetic geneFUM1 to generate double-stranded RNA inF.verticillioides. Several of the resulting transformants exhibited reducedFUM1 gene expression and fumonisin production (24- to 3675-fold reduction in fumonisin FB1). Similar reductions in fumonisin production resulted from double-stranded RNA constructs with segments ofFUM8, another fumonisin biosynthetic gene (3.5- to 2240-fold reduction in fumonisin FB1).FUM1 orFUM8 silencing constructs were transformed into three isolates ofF.verticillioides. Whole genome sequence analysis of seven transformants revealed that reductions in fumonisin production were not due to mutation of the fumonisin biosynthetic gene cluster and revealed a complex pattern of plasmid integration. These results suggest the cloned...
Source: Mycotoxin Research - Category: Toxicology Source Type: research