DIRECT DEFENSES IN DEVELOPING SEEDS OF SOYBEAN AGAINST GREEN STINK BUGS (Nezara viridula)

BARNETO, J; ZAVALA J.A.; PAGANO, E

Potrero de los Funes

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

Insect attack increases the production of defenses, which are regulated by the phytohormone jasmonic acid (JA). Southern green stink bug (<i>Nezara viridula</i>) is one of the main pests in soybean and affects both yield and seed quality. However, little is known about soybean response to stink bug attack on developing seeds. Developing seeds of soybean contain only lipoxygenases 1, 2, and 3, which probably regulates JA accumulation in these organs. Our aim was to determine the role of JA in the regulation of induced defenses, such as proteinase inhibitors (PI), when soybean seeds are attacked by stink bugs. We used the Williams mutant BRM 926600 genotype, without expression of <i>lox</i>1, 2 and 3; and Williams <i>wt</i> as a control. Four treatments were applied on seed pods: i) without damage; ii) mechanical damage; iii) damage produced by stink bugs attack and; iv) application of methyl jasmonate (MeJA). The transcriptional expression of <i>lox</i> genes and pi were estimated by the RT-PCR reaction. Stink bug attack and mechanical damage induced gene expression of <i>lox</i>1, 2 and 3, and pi in control. <i>Lox</i>3 expression explained better the variation in the expression of inhibitors than <i>lox</i>2 and 3. Although, no expression of either <i>lox</i>1, 2, 3 or pi were found in the mutant BRM, application of MeJA recuperated the expression of these genes, suggesting that JA regulate PI en developing seeds of soybeans.