ABSTRACT
Mycotoxin contamination of crops in the US occurs most frequently in specific regions and on specific crops (1) which strongly suggests that the growth environment (that is, moisture, temperature, and light), the genotype of the host plant, and the genotype of the fungal pathogen (or saprophyte) all play important roles in determining the degree of mycotoxin contamination. These factors directly or indirectly control the expression of genes involved in mycotoxin synthesis. An understanding of the genetic mechanisms that regulate mycotoxin gene expression will lead to novel control methods to reduce or eliminate contamination of food and feed crops. This chapter will provide the reader with current information regarding the genetic mechanisms that regulate mycotoxin gene expression in response to the growth environment. Although many mycotoxins are important from an economic and health standpoint, we provide examples primarily from the aflatoxins, trichothecenes, and fumonisins to illustrate key points, because a significant body of information has accumulated regarding the genes involved in their synthesis (23,118,142). Less is known about other groups of mycotoxins and these will be discussed only to a limited extent.
