CIS-JASMONE RESISTANCE INDUCER FOR Aphis craccivora Koch 1854 IN Vigna unguiculata L. Walp

Abstract

Cowpea, Vigna unguiculata (L.) Walp. (Fabaceae), is an important dietary legume in Brazil, with an annual production of about 850 thousand tons. One of the limiting factors for its production is the black aphid, Aphis Craccivora Koch 1854 (Hemiptera: Aphididae), as it is a mechanical vector of viruses. In order to study cis-jasmone (CJ) action as resistance inducer in cowpea plants, a compound described in the literature that this plant defense elicitor activates plant defense mechanisms by altering the composition and emission of Volatile Organic Compounds. The present work aims to study the action of CJ and its role in the activation of the defense mechanism in cowpea plants, contributing to the development of a methodology for the control of black aphid. Two cowpea genotypes were used: Vita 7 (susceptible) and BRS-Guariba (resistant) to evaluate the VOC profiles were submitted to the following treatments: Control, Infested, Control with CJ application and infested with CJ application. The extracts obtained were analyzed by gas chromatography coupled with mass spectrometer (MS) to identify the compounds present in each treatment. The plants of cultivated cowpea showed distinct VOC profiles in the four treatments. In the comparison between treatments the cultivated Guariba with application of CJ showed an increase in the intensity of its compounds when compared to its control plants. In the treatments, infested and infested with application of CJ the Vita 7 presented the VOC profile similar to that of BRS-Guariba, possibly related to activation of resistance mechanisms mediated by CJ. This study provides an example of variation in VOC profiles and intensity caused by the use of resistance inducing CJ.