A comparative analysis of mitotic chromosomes of Theobroma cacao (cacao) and T. grandiflorum (cupuaçu) was performed aiming to identify cytological differences between the two most important species of this genus. Both species have symmetric karyotypes, with 2n = 20 metacentric chromosomes ranging in size from 2.00 to 1.19 μm (cacao) and from 2.21 to 1.15 μm (cupuaçu). The interphase nuclei of both species were of the arreticulate type, displaying up to 20 chromocentres, which were more regularly shaped in cacao than in cupuaçu. Prophase chromosomes of both species were more condensed in the proximal region, sometimes including the whole short arm. Both species exhibited only one pair of terminal heterochromatic bands, positively stained with chromomycin A 3 , which co-localized with the single 45S rDNA site. Each karyotype displayed a single 5S rDNA site in the proximal region of another chromosome pair. Heterochromatic bands were also observed on the centromeric/pericentromeric regions of all 20 chromosomes of cacao after C-banding followed by Giemsa or DAPI staining, whereas in cupuaçu they were never detected. These data suggest that the chromosomes of both species have been largely conserved and their pericentromeric chromatin is the only citologically differentiated region.

Podocarpus sellowii (Podocarpaceae) is one of only a few gymnosperms native to Brazil and the sole species of the genus found in the northeastern region of that country. It has a very restricted distribution in this region, with only three known populations in highland forests (called Brejos de Altitude), which apparently have been isolated from each other since the Pleistocene. Due to this long-term isolation and the fact that these populations have few adult individuals and suffer great anthropogenic pressure, low genetic variability is expected, compromising their long-term viability. The present work assessed the genetic variability and structure of northeastern populations of P. sellowii to investigate the role of Pleistocene glaciations on the genetic relationships between them and to propose strategies for their conservation by analyzing the SSR and ISSR markers of adult and juvenile individuals. Low genetic diversity was found with both markers, associated with a high differentiation of the Brejo de Baturité population in relation to the others-suggesting their isolation at different points in time, probably during the Pleistocene. Actions directed towards increasing the genetic diversity of these populations will be needed, such as planting seedlings with high genetic variability-but the high degrees of differentiation observed between the populations must be taken into account.

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Ten microsatellite markers were developed using next-generation sequencing data for Alibertia edulis (Rubiaceae), a widely distributed species typical of Cerrado (Brazilian savanna) vegetation. The markers were polymorphic in the two populations analyzed. The numbers of alleles, and observed (H O ) and expected (H E ) heterozygosities per polymorphic locus ranged from 2 to 11, 0.091 to 1.0, and 0.100 to 0.937 respectively. The SSR loci demonstrated moderate to high polymorphism values in both populations analyzed, with PIC values ranging from 0.26 to 0.91, and total allele numbers ranging from three to 16. The inbreeding coefficient values were generally higher in the Piauí population (ranging from − 0.593 to 0.762) than in the Mato Grosso population (ranging from − 1 to 0.575). The differences observed between those disjunct populations suggest they harbor different alleles, which has implications for Cerrado conservation strategies. Those loci will be useful for population studies of A. edulis.

Coniferous trees of the genus Pinus (Pinaceae) are under continuous threats by numerous herbivorous insect species and pathogens attacking nearly all parts and tissues of the plants. To defend themselves, pine trees produce large amounts of oleoresin that is accumulated in a highly developed network of specialized resin ducts, which are distributed in the wood, bark, and needles. Such defense reactions in pines can be induced by the attack of herbivores. The banded pine weevil, Pissodes castaneus (De Geer, 1775) (Coleoptera, Curculionidae), is an important pest of Pinus in Brazil, where it has been an invasive species since 2001. The female lays its eggs under the tree bark of trees and the larvae feed in the phloem of the trunk and branches, interrupting the sap circulation and eventually causing its death. In the present study, we conducted detailed GC–MS analyses of volatiles emitted by twigs of Pinus taeda L. We analyzed how the attack by P. castaneus males and females affects the volatile pattern emitted by the twigs. When comparing volatiles produced by healthy plants and by female- and male-attacked P. taeda, qualitative and quantitative differences were detected, as the decreased production of limonene, germacrene D and (E)-caryophyllene and the increase of α-pinene. Laboratory bioassays showed that plants attacked by male and female P. castaneus were more attractive to the insects. Understanding about what compounds may attract or repel the insects may help in the development of more effective traps, as well as preventing stress to avoid infestation.

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