Digestive responses of Anticarsia gemmatalis larvae to soybean (Glycine max) protease inhibitors

TEJEDOR, D; PAGANO, E; ZAVALA J.A.

Potrero de los Funes

Congreso; XLVII Reunión anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular.; 2011

Anticarsia gemmatalis is a major pest of soybean (Glycine max). However, soybean has digestive protease inhibitors (PI) as a defense against insects attack. Although these PI are an effective defense many herbivores, the mortality of A. gemmatalis is very low. Thioredoxins proteins (Trxs) are able to reduce disulfide bonds in some proteins such as those found in PI. The Trx in the gut of A. gemmatalis could be a component of the resistance to the soybean PI. The aim of this study was to sequence Trx from A. gemmatalis to analyze Trx expression from guts of larvae that fed on diets with different levels of PI. We designed primers from Trxs of related species and specific cDNA were obtained and sequenced. Larvae were fed on diets containing different percentages of soybean seeds. We obtained total coding sequence with 98% of similitude to related species, and its conserved active site. Trx expression increase 120% in larvae that fed on diet containing 80% of seeds, and 70% expression in larvae that fed diet with 20% of seeds compared to PI-free diet (control). Survival and weight gain of larvae was also measure. Larvae that fed on 80% raw soybean had 60% survival compared to the control, and a weight gain 90% less, in the case of larvae that fed with 20% of raw soybeans showed 8% lower weight gain. This suggests a direct involvement of the A. gemmatalis’ Trx against soybeans PI.