Changes in the volatile organic profile of Schinus polygamus (Anacardiaceae) and Baccharis spicata (Asteraceae) induced by galling psyllids

Abstract

Baccharis spicata (Asteraceae) e Schinus polygamus (Anacardiaceae) são plantas nativas do Rio Grande do Sul e são hospedeiras de dois psilídeos galhadores (Hemiptera, Psyllidae) ainda não identificados. As duas plantas em estudo produzem óleo essencial e seus compostos voláteis podem ter um importante papel na interação inseto-planta. A extração e análise dos voláteis das folhas, folhas galhadas e galhas foram realizadas por microextração em fase sólida no modo "headspace" e por cromatografia gasosa com detector de espectrometria de massas. Verificou-se que a composição do "headspace" das galhas de B. spicata e S. polygamus é diferente daquela do "headspace" das folhas sadias. A principal alteração observada foi o aumento da contribuição de monoterpenos no "headspace" das galhas comparativamente ao que se verificou nos tecidos saudáveis. Algumas mudanças também foram observadas na produção de voláteis verdes, em ambas as espécies, mas especialmente na S. polygamus. O possível papel ecológico desses compostos químicos também é discutido.Baccharis spicata (Asteraceae) and Schinus polygamus (Anacardiaceae) are plants native from Rio Grande do Sul and are hosts of two unidentified galling psyllids (Hemiptera, Psyllidae). Both plant species produce essential oil and their volatile compounds play an important role related to this kind of plant-insect interaction. Extraction and analysis of volatiles produced by leaves, galled leaves and galls were performed using headspace solid phase microextraction and gas chromatography coupled to mass spectrometry detector. Composition of the headspace of B. spicata and S. polygamus galls showed a significant change in their volatile profile when compared to healthy leaves. These changes were mainly related to a higher production of monoterpenes in galled tissue, compared to what was found in healthy samples. Some changes on the production of green leaf volatiles were also observed in both plant species, especially in S. polygamus. The possible ecological role of these chemical changes was discussed. Keywords: galls, leaves, Baccharis spicata, Schinus polygamus, headspace solid phase microextraction IntroductionGalls are the result of histological alterations in plant organs, mainly hypertrophy and hyperplasy, caused by the activity of an inductor which can be virus, bacteria, nematodes, insects and other plants. These organisms can interfere with the normal development of cells and tissues leading to several physiological and morphological changes. Gall-inducing insects (insect gallmakers) are masters in the art of beguiling or compelling the host plant to provide food and shelter with a minimum expenditure of effort on their part and galls induced by insect are one of most diverse plant galls.1 Galls are found on all plant organs, such as flowers, leaves, stems and roots. They provide food and shelter to the inducer which lives in a microenvironment relatively safe from natural enemies.2 The leaf galls are variable in form and occur in the majority of plant hosts. 2Plant volatil...

Sedative effects of essential oils obtained fromBaccharis uncinella

“…The volatile metabolites in Baccharis are likely to be influenced by ecological and geographical factors as luminosity (Silva et al, 2006), rainfall regime (Ferracini et al, 1995), ground mineral content (Silva et al, 2007) and/or interaction with insects and predators (Damasceno et al, 2010), and the occurrence of chemotypes based on sesquiterpenes has been also reported (Frizzo et al, 2008). It is therefore arguable that the distinct composition of BU-SC and BU-PR are related to ecological or genetics factors; it is to be expected that the differences observed in these samples CNS activities are consequent to these differences in composition.…”

Chemical composition similarity between the essential oils isolated from male and female specimens of each five Baccharis species

“…1,2 On the other hand, the available data show that about 52 species from the Baccharis genus have been characterized on the basis of the chemical composition of their essential oils. The seasonal variability of the chemical composition of essential oils from some Baccharis species cultivated or growing in natura has already been reported, and it is widely accepted that ecological and geographical factors, such as luminosity, 3 rainfall regimes, 4 mineral content in the soil, 5 interaction with insects and predators, 6 and location and altitude, 7 exert influence on the content of volatile metabolites in plants of this genus. In addition, the extraction method used to obtain the essential oil may affect its chemical composition.…”

Insect Gallers and Their Plant Hosts: From Omics Data to Systems Biology

“…The involvement of this mechanism in plant-galler interactions has been demonstrated in a few systems. For example, Damasceno et al [72] showed that feeding by unidentified galling psyllids caused a change in the volatile profile of Schinus polygamous (peppertree) and Baccharis spicata . Similarly, Oates et al [23] showed that the blue gum chalcid wasp, Leptocybe invasa , induced changes in the volatile terpene profile of a resistant or susceptible host.…”