Atividades bioquímicas induzidas por herbivoria de percevejo em feijoeiro (Phaseolus vulgaris L.)

Abstract

Common bean (Phaseolus vulgaris L.) is one of the most important agricultural crops in Brazil and is frequently affected by insect pests, particularly stink bugs (Nezara viridula, Dichelops furcatus, and Euschistus heros). Feeding by these insects can significantly reduce grain yield and quality while triggering physiological and biochemical responses in plants. This study aimed to evaluate the biochemical changes induced by stink bug herbivory in common bean, focusing on protein content, free amino acid content, and phenylalanine ammonia-lyase (PAL) activity. The experiment was conducted in a completely randomized design using a 3 × 2 factorial arrangement. Plants were subjected to different levels of herbivory, with two and four stink bugs per experimental unit, and samples were collected before and after five days of insect exposure. The results showed a significant increase in protein content and a significant reduction in free amino acid content after the herbivory period, regardless of herbivory intensity. No statistically significant differences were observed for PAL activity. These findings suggest that herbivory promotes metabolic reorganization in common bean, possibly associated with the synthesis of proteins involved in plant defense mechanisms. This study contributes to the understanding of the biochemical responses induced by stink bug herbivory and provides valuable information to support the development of sustainable pest management strategies.