VOLATILE ORGANIC COMPOUNDS FROM FUSARIUM VERTICILLIOIDES AS NATURAL INDUCTOR OF MAIZE KERNEL DEFENSE

JACQUAT, AG; ZYGADLO, JA; PORPORATTO, C; JACQUAT, AG; PIZZOLITTO, RP; ZYGADLO, JA; ARECO, VA; PORPORATTO, C; DAMBOLENA, JS; PIZZOLITTO, RP; ARECO, VA; DAMBOLENA, JS; USSEGLIO, VL; ZUNINO, MP; BOH, LP; USSEGLIO, VL; ZUNINO, MP; BOH, LP

Valparaíso

Congreso; V Congress of the Latin American Association of Chemical Ecology (ALAEQ),; 2018

Asociación Latinoamericana de Ecología Química

The silo is a man-made environment where a large number of biological interactions, such as insect-fungal associations, are produced and these cause significant economic losses. This is the case of the interaction between the maize weevil (Sitophilus zeamais) and the maize-infecting fungus Fusarium verticillioides. Due to the problems caused by synthetic pesticides, interest has grown in the use of alternative strategies based on semiochemicals such as those derived from communication between attacked plants and healthy neighboring plants, activating the defense system. In this work it is proposed that volatile organic compounds (VOCs) emitted by F. verticillioides, could condition healthy maize kernels, increasing the activity of the LOX path, affecting the behavior of S. zeamais. In tests of susceptibility to attack of the insect, made in two-way olfactometers in which unconditioned maize grains (control) with conditioned grains (treatment) was observed that, after 20 days, the treatment kernels are less attacked by S. zeamais. In a second instance, the LOX activity, from treated and control corn kernels, was measured spectrophotometrically. In these tests, a 1.755-fold increase in the activity of the LOX enzymes of treated kernels with respect to control kernels was obtained. In agreement with this result, when a semi-quantitative analysis of the polypeptide profile of the treated and control maize kernels was made, an increase was observed in the area of the band whose molecular weight corresponds to the LOX enzymes, in conditioned kernels. Finally, the results of gene expression analysis confirmed an increase in the expression of genes coding for LOXs in conditioned kernels with fungal VOCs. Together these experiments allow to suppose an induction of the defense system of maize kernel when exposed to VOCs produced by F. verticillioides, suggesting that the kernels could identify these compounds and increase their defense mechanisms and the production of VOCs derived from the LOX pathway.