Chemical defense responses in Eucalyptus globulus (Labill) plants

Abstract

This study evaluated the expression of defense compounds by the secondary metabolism of Eucalyptus globulus plants subjected to attacks by the insect Ctenarytaina eucalypti (blue gum psyllid) and abiotic mechanical damage using gas chromatography with flame ionization detection (GC-FID) and mass detection (MS). The results show that both biological and mechanical attacks activated defense responses in the plants. We identified 34 compounds in the leaves of the treated plants. In the case of the plants damaged by C. eucalypti, four of the compounds differed from those of the control: three oxygenated monoterpenes (borneol, exo-2-hydroxy cineole and thymol) and one quinone (6-acethyl- flaviolin). In the case of the mechanical damage, five compounds differed from the control: three sesquiterpenes (alloaromadendrene, eremophilene, and caryophyllene-oxide), borneol, and 6-acethyl-flaviolin. According to the results, different compounds are biosynthesized when faced with biotic and abiotic inductions, indicating a certain level of specificity in the response of the plants to different types of damage.