Diversidade genética, caracterização e atividade de óleos essenciais em Psidium spp
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Data
2017-04-25
Autores
Bernardes, Carolina de Oliveira
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Universidade Federal do Espírito Santo
Resumo
Myrtaceae is one of the most important families in the ecosystems of Brazil presenting as an important characteristic being rich in essential oil. The genus Psidium is one of the most explored in the family and it represents 100 species, approximately, where P. guajava, P. brownianum and P. guineense are detached. It was aimed with this work to study the genetic diversity of P. guajava, P. brownianum and P. guineense, to identify the terpenic profile of essential oils of Psidium species and to use the essential oils properties from P. guajava as an alternative to the control of Spodoptera frugiperda. For the diversity studies, the same group of microsatellite markers was used in populations from the three species. The higher number of alleles was detected for P. guajava populations and elevated values of He and H’ were found for the populations of the three species. Among 73 and 80% of variation occurred within populations, reflecting elevated values of genetic divergence (P. guajava, FST = 0.1996; P. brownianum, ØST: 0.2636; P. guineense, ØST: 0.2034). Populations of the three studied species were moderately structured, with the formation of two main groups, representing the South and North regions of the state of Espírito Santo. Regarding the terpene variability of the leaves essential oils, eleven species were analyzed with GC-FID and GC-MS, as well as by leaf microbiology analysis and herbivory index. Fifty-nine components were identified, with the predominance of sesquiterpenes. Literature data was obtained and fourteen species were included in this study. Elevated diversity for the oil’s components was observed, as well as the predominance of ß-caryophyllene and caryophyllene oxide. Additionally, 1,8-cineole, apinene and (E)-nerolidol were also responsible for distinguishing groups of species in cluster analysis. The herbivory index was low for all the species; it is explained by the fact that sesquiterpenes are directly related to the defense against microorganisms and predators. The presence of trichomes and coriaceous leaves, also contributed for the herbivory reduction. At last, the effect of two chemotypes of guava essential oil was studied in Spodoptera frugiperda caterpillars. The chemical composition of the essential oils showed the presence of thirteen components in both genotypes. The major components identified in Paluma were caryophyllene oxide (15.9%), ß-caryophyllene (12.1%) and selin-11-en-4-a-ol (10.3%) and in Cortibel VII, ß-bisabolol (12.3%). Both essential oils presented repellency effect, under the concentrations of 10 and 100 ppm to S. frugiperda caterpillars. This way, the knowledge of genetic diversity is an important tool that may show the real situation of species regarding their conservation status in determined environments. Besides, with the information about Psidium spp. essential oils composition, it is possible to understand what chemotypes may be present in such species and this way, indicate the correct use of the essential oil.
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Palavras-chave
SSR markers , Genetic structure , Volatile oils , Chromatography , Biological activity , Myrtaceae , Marcadores SSR , Estrutura genética , Óleos voláteis , Cromatografia , Atividade biológica