Effect of Long-Term Feeding by Borers on the Antibiotic Properties of Corn Stems.

Plant long-term response against chewing insects could become stronger than initial reactions and even turn into systemic. The objectives of the present study were 1) to evaluate whether the long-running attack to the stem by corn borers can improve the stem antibiotic properties; 2) to check whether hydroxycinnamic acids could be involved in this antibiotic response; 3) and to check whether elicitation by Sesamia nonagrioides Lef. (Lepidoptera: Noctuidae) regurgitant could activate long-term plant responses. In this sense, we observed that long-term feeding by S. nonagrioides larvae induced genotype-dependent changes in stem antibiosis and phenolic profiles, but the hydroxycinnamate content does not have a significant role in the systemic defense induced by the attack. In addition, response to long-term feeding by larvae could not be fully mimicked by elicitation using S. nonagrioides regurgitant alone. For the first time, it has been demonstrated that 'long-term' attack to the stem by corn borers can increase the stem antibiotic properties, and this has to be considered attending to breeding strategies.