Evolution and characterization of serine protease gene family and its association with the feeding behavior in Noctuidae moths

Abstract

Noctuidae moths (Lepidoptera) are known by damages caused to different plants. This insect family comprises important pests, some of them with diets ranging from one to many hosts. The evolutionary process that led closed species to adapt to specialist or generalist behavior is not completely elucidated, especially regarding to the molecular mechanisms involved. It is known that during evolution plants have developed a series of artifacts to their defense against herbivore insects. One of these strategies is the expression of protease inhibitors (PIs) that bind to insect digestive proteases and block their function. Among the proteases found in the midgut of Lepidoptera insects, the serine proteases (SPs) are the main endopeptidases in this organism. In previous studies, it was observed that in Spodoptera frugiperda (a generalist insect), the expression of some SPs is changed by the presence of plant IPs in the diet, occurring the increasing or even de novo synthesis of this enzymes. These results suggest that the regulation of SPs expression have important role in the response to plant IP ingestion. It is believed that these enzymes can be associated with adaptation to generalism in these insects. Using data of the midgut transcriptome of the three moths with three different feeding behaviors of the Noctuidae family, this project aims to analyze, considering evolutionary and structural characterization approaches, the SPs that are found in the midgut of this insects. We are seeking to understand if it is a correlation among the SP gene family diversification and the evolution of generalism inside the Noctuidae family. (AU)