Responses of developing seeds of soybean to stink bug (Nezara viridula) attack and its effects on insect preference? Illini

JORGE A. ZAVALA; BARRIGA LUCÍA G.; DILLON FRANCISCO M.; BARNETO JÉSICA A.; PEDRO M. SARDOY; DI SANTO CAROLINA; PAGANO EDUARDO A.; CHLUDIL HUGO

illinois

Congreso; 30th meeting of the International Society of Chemical Ecology; 2014

University of Illinois at Urbana-Champaign

Soybean (Glycine max), the most important legume crop in South and North America, is attacked by the southern green stink bug (Nezara viridulaL. Hemiptera: Pentatomidae). Temperate regions of Brazil and Argentina and the southern of U.S. states are invaded by stink bugs, which reduce soybean crop yield. Stink bugs can puncture most aboveground plant parts with their piercing-sucking mouthparts but preferentially feed on young developing seeds. Although studies have shown that plants respond to insect damage by up-regulation of defenses, most of the available evidence comes from studies that focused on leaf damage. Here we present the responses of developing seeds to stink bug damage and the effects of plant defenses on insect behavior. While stink bug attack induced early accumulation of the defense hormone jasmonic acid (JA) in seeds, 72 h after attack salicylic acid (SA) accumulation increased and JA decreased. The hormonal changes induced expression and activity of cysteine and trypsin proteases inhibitors, and expression of genes related to synthesis and perception of JA and genes related to isoflavonoid synthesis were up-regulated. Preference choice experiments demonstrated that stink bugs feed on developing seeds with low defense levels. Our results suggest that seeds respond to stink bug attack, inducing chemical defenses regulated by both SA and JA, and insects avoid seeds with induced defenses