Thanise Nogueira Füller

Reference Genes for qPCR Analysis in Resin-Tapped Adult Slash Pine As a Tool to Address the Molecular Basis of Commercial Resinosis

Pine oleoresin is a major source of terpenes, consisting of turpentine (mono- and sesquiterpenes) and rosin (diterpenes) fractions. Higher oleoresin yields are of economic interest, since oleoresin derivatives make up a valuable source of materials for chemical industries. Oleoresin can be extracted from living trees, often by the bark streak method, in which bark removal is done periodically, followed by application of stimulant paste containing sulfuric acid and other chemicals on the freshly wounded exposed surface. To better understand the molecular basis of chemically-stimulated and wound induced oleoresin production, we evaluated the stability of 11 putative reference genes for the purpose of normalization in studying Pinus elliottii gene expression during oleoresinosis. Samples for RNA extraction were collected from field-grown adult trees under tapping operations using stimulant pastes with different compositions and at various time points after paste application. Statistical methods established by geNorm, NormFinder, and BestKeeper softwares were consistent in pointing as adequate reference genes HISTO3 and UBI. To confirm expression stability of the candidate reference genes, expression profiles of putative P. elliottii orthologs of resin biosynthesis-related genes encoding Pinus contorta β-pinene synthase [PcTPS-(−)β-pin1], P. contorta levopimaradiene/abietadiene synthase (PcLAS1), Pinus taeda α-pinene synthase [PtTPS-(+)αpin], and P. taeda α-farnesene synthase (PtαFS) were examined following stimulant paste application. Increased oleoresin yields observed in stimulated treatments using phytohormone-based pastes were consistent with higher expression of pinene synthases. Overall, the expression of all genes examined matched the expected profiles of oleoresin-related transcript changes reported for previously examined conifers.

Stimulant Paste Preparation and Bark Streak Tapping Technique for Pine Oleoresin Extraction

Tapping technique comprises the extraction of pine oleoresin, a non-wood forest product consisting of a complex mixture of mono, sesqui, and diterpenes biosynthesized and exuded as a defense response to wounding. Oleoresin is used to produce gum rosin, turpentine, and their multiple derivatives. Oleoresin yield and quality are objects of interest in pine tree biotechnology, both in terms of environmental and genetic control. Monitoring these parameters in individual trees grown in the field provides a means to examine the control of terpene production in resin canals, as well as the identification of genetic-based differences in resinosis. A typical method of tapping involves the removal of bark and application of a chemical stimulant on the wounded area. Here we describe the methods for preparing the resin-stimulant paste with different adjuvants, as well as the bark streaking process in adult pine trees.

Chemical diversity of wild populations of Elionurus muticus (Spreng.) and the allelopathic effect of its essential oil

Abstract Elionurus muticus is a native grass from Brazil that has been shown to have large variability in the chemical constituents of its essential oil. However, few studies have evaluated this species. The aims of this study were to chemically characterize four wild populations of E. muticus that were collected in southern Brazil as well as to evaluate the allelopathic effect of the essential oil, which is rich in citral. Chemical analyses were performed using gas chromatography and mass spectrometry. The phytotoxic activity was evaluated with onion and lettuce seeds. The results showed that the studied populations have chemical variability based on their geographic origin, which indicates the possibility of chemotypes. The results obtained with E. muticus essential oil, reveals phytotoxic activity on the germination and growth of lettuce and onion.

A Modified Protocol for High-Quality RNA Extraction from Oleoresin-Producing Adult Pines

RNA extraction resulting in good yields and quality is a fundamental step for the analyses of transcriptomes through high-throughput sequencing technologies, microarray, and also northern blots, RT-PCR, and RTqPCR. Even though many specific protocols designed for plants with high content of secondary metabolites have been developed, these are often expensive, time consuming, and not suitable for a wide range of tissues. Here we present a modification of the method previously described using the commercially available Concert™ Plant RNA Reagent (Invitrogen) buffer for field-grown adult pine trees with high oleoresin content.

Potencial inseticida de óleos de origem vegetal sobre Grapholita molesta (Busck) (Lepidoptera: Tortricidae)

As a result of the study on the chemical interactions between insects and herbivores and the advancement of phytochemical research studies, a variety of natural products with great insecticidal potential are described in the literature. The Grapholita molesta (Busck) (Lepidoptera: Tortricidae), commonly known as Oriental Fruit Moth, is a major peach pest damaging shoots and fruits. The purpose of this study was to assess the mortality, attractiveness and deterrence of vegetable oils in G. molesta. Insect eggs and pupae artificially created were immersed in the essential oils of Elionurus muticus (Spreng.) Kuntze and/or Cymbopogon winterianus Jowitt ex Bor at the concentrations of 0.25%, 0.5%, 1% and 0.5%, 1%, 5%, respectively. The attractiveness tests were performed in a Y-Tube olfactometer. Oviposition deterrence was tested in no-choice and dual-choice cages. Oil of E. muticus applied in eggs of G. molesta at three concentrations caused mortality above 30%, which differs significantly from controls (p<0.05). Mortality caused by citronella oil was approximately 70%, significantly higher than control (p<0.01). The application of citronella oil at 1% in pupae caused mortality of 99.8%. There was no attractiveness of adults in the olfactometer test for any of the oils. Citronella oil presented oviposition deterrence, as the mean number of eggs in the substrate with the treatment (0.33 ± 0.33) is significantly lower than in the control (7.3 ± 0.88) (p<0.01).