DIMBOA action in corn

​2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one, also known as DIMBOA is known as insect growth inhibitor in corn.  It has been shown to reduce the digestibility of food by European corn borer by acting as a digestion toxin.  DIMBOA degrades into a related product in corn called MBOA that reduces the digestibility of food in the corn borer. Not all varieties produce the same amount of DIMBOA.  In the popular hybrid B73 x Mo17, B73 was very low in DIMBOA content and Mo17 was very high.  The hybrid was intermediate to these two parents.  Selection for higher DIMBOA content was shown to be possible.  Highest concentration was in young plants, including the roots.
 
Fall armyworm (Spodoptera) have been shown to detoxify DIMBOA but the plant responds by synthesizing a related compound (HDMBOA-glc) to defend against this insect (Plant J 68: 901–911).  Another indication of plant’s metabolic interaction with potential predators.
 
High concentrations of DIMBOA in the corn root tissue are released into the soil surrounding the root tissue.  This inhibits some potential pathogens of the root.  A few beneficial bacteria have evolved tolerance to DIMBOA, allowing them to invade and dominate the area around the corn roots. (http://dx.doi.org/10.1371/journal.pone.0035498)
 
There is a lot of unseen biology going on in a corn field.