Effect of intraspecific competition among soy plants (Glycine max L.) on the defensive responses induced by Anticarsia gemmatalis H.

REPETTO, A; 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

Plants respond to insect attack with an increase in the production of toxic compounds which decrease or stop the attacks. Jasmonic acid plays an important role in the induction of defensive responses and its biosynthesis is regulated by the enzyme lipoxigenase (LOX). However, production of defenses against insect attack can be diminished as a consequence of intraspecific competition. Increase in plant density reduce red / far red ratio detected by phytochrome resulting in the promotion of a less capacity of plants to defend theirselves against insect. One of the most anti herbivore defenses studied are the proteinse inhibitors. The aim of this work was analyze the effects of intraespecific competition in the production of insect-induced defenses. The commercial soy genotype DM 4670 was sown with three different distancing between plants: 20, 40 and 60 cm. Leafs attacked and no attacked by Anticarsia gemmatalis H. were harvested at 24 and 72 hours to study the expression of Lox8 and proteinase inhibitors N2, L1, R1 y Bowman-Birk I (BB1) by RT-PCR. Lox8, N2, L1, R1 y BB1 were induced by the attacks of A. gemmatalis suggesting that Lox8 regulates the level of expression of N2. It was identified a high rate of responses in plants sown under low density in contrast with the high level of expression observed in plants sown under high density.