-Amylase inhibitors of the coffee berry borer Hypothenemus hampei in different plant species

Abstract

Antibiosis is one of the mechanisms of plant resistance to insect attack in which plant defense proteins, like -amylase inhibitors, are involved. These inhibitors are found mainly in the seeds of leguminous and graminaceous plant species. In Phaseolus vulgaris L. var. Radical, an amylase inhibitor of the coffee berry borer Hypothenemus hampei Ferrari has been reported, with up to 80% inhibition, which also inhibits -amylase of mammals. It is necessary to search for new -amylase inhibitors in other plant species that have an effect similar to beans and with specificity to insect aamylases. Protein extracts were obtained from the seeds of eight plant species from  the families Gramineae and Leguminosae. With these extracts and a commercial -amylase inhibitor from wheat (Triticum aestivum L.), tests were conducted on the inhibitory activity in the coffee berry borer evaluated with spectrophotometry using the Bernfeld method and zymograms of  enzymatic inhibition. The species that showed more than 50% inhibition of -amylases in the coffee berry borer were maize (Zea mays L.), Brachiaria  decumbens Stapf and the commercial inhibitor from wheat, their activity corroborated with the inhibition zymograms. While No inhibition of mammal -amylases were found for Brachiaria or maize, while the commercial inhibitor from wheat -amylases showed more than 50% inhibition. In addition, the effect of Brachiaria and maize extracts were evaluated on different stages of the coffee berry borer in artificial diets, resulting in larval mortalities of 40 and 95%, respectively. Therefore, these two species are promising for the identification of a promissory source of genes coding that code for such these inhibitory proteins and to develop a genetic base that could conferfor resistance to the coffee berry borer.