Shoot and Root Communication in Corn in Response to Insect Attack

Corn has natural defense mechanisms against insects, these mechanisms are orchestrated by communication between shoots and roots that uses the vascular system as an information highway for defense messages. At the onset of insect herbivory, corn roots and shoots are able to produce several messages that trigger direct defenses such as the production of the cysteine protease MIR1-CP, which accumulates in leaves and degrades the peritropic matrix of the attacking caterpillar’s midgut. Our hypothesis is that plant defense mechanisms have different features depending on the tissue under attack and the type of insect infesting the plant. We are studying protein profiles of the corn inbred lines, Tx601 (insect susceptible) and Mp708 (insect resistant), in response to leaf infestation by Spodoptera frugiperda (fall armyworm). The objective of this research is to observe plant responses to the pest in root, shoot and stem exudates by identifying proteins that have a vital impact on plant defense mechanisms in specific tissues. Future experiments will involve creating proteome profiles of these tissues from corn roots infested with Diabrotica virgifera virgifera (Western corn root worm) to compare with the Spodotera profiles. Identification of these protein profiles will facilitate building a communication network of corn defense mechanisms in shoots, roots and stem. Once this network is created, we will be able to understand several currently unknown pathways of corn insect resistance.  Ultimately this will facilitate the introduction of insect resistance traits into commercial corn lines and other crops.