D3243: Binding site model for Cry proteins in the eucalypt defoliator Thyrinteina arnobia

The eucalyptus brown looper, Thyrinteina arnobia (Lepidoptera: Geometridae), is one of the most critical caterpillar defoliators of eucalyptus plantations in Brazil. Biopesticides and releasing natural enemies, such as parasitoids and predatory bugs, are the current primary control methods. However, severe outbreaks in Brazil have led to the prospection of alternative approaches for effective management, including the development of transgenic Eucalyptus-producing Cry pesticidal proteins from Bacillus thuringiensis active against T. arnobia. We report binding competition assay results in the midgut of T. arnobia that disclose a binding model specifying pesticidal Cry proteins that do not share binding sites. These results suggest a distinct mode of action of each Cry protein in T. arnobia and identify a set of pesticidal protein candidates for gene pyramiding in transgenic Eucalyptus, hindering resistance evolution.