Guarana (Paullinia cupana var. sorbilis) is a plant native to the central Amazon basin. Roasted seed extracts have been used as medicinal beverages since pre-Colombian times, due to their reputation as stimulants, aphrodisiacs, tonics, as well as protectors of the gastrointestinal tract. Guarana plants are commercially cultivated exclusively in Brazil to supply the national carbonated soft-drink industry and natural product stores around the world. In this report, we describe and discuss the annotation of 15,387 ESTs from guarana seeded-fruits, highlighting sequences from the flavonoid and purine alkaloid pathways, and those related to biotic stress avoidance. This is the largest set of sequences registered for the Sapindaceae family.

Rosewood (Aniba rosaeodora Ducke, lauraceae) is an amazonian evergreen tree and a source of the purest linalool, the main component of its essential oil, which is very valuable in the international perfumery market. after decades of over-exploitation it is currently considered as threatened. We evaluated the genetic diversity and its distribution in four populations in Central amazonia. thirty-five reliable RaPD markers were generated, of which 32 were polymorphic (91.4%). variation was higher within the populations (76.5%; p < 0.0001) and geographic distribution contributed to population differentiation (23.4%; p < 0.0001). the amazon River had a small influence on gene flow (3.3%; p < 0.0001), but we identified evidence of gene flow across the river. there were significant differences in marker frequencies (p < 0.05), in agreement with the low gene flow (Nm = 2.02). the correlation between genetic distance and gene flow was -0.95 (p = 0.06) and between geographic distance and gene flow was -0.78 (p = 0.12). there was a geographic cline of variability across an east-West axis, influenced as well by the amazon River, suggesting the river could be a barrier to gene flow. although threatened, these Rosewood populations retain high diversity, with the highest levels in the manaus population, which has been protected for over 42 years in a Reserve.Keywords: RaPD, linalool, gene flow, amazon Rainforest.Padrão geográfico de diversidade genética em populações naturais de Pau-rosa (Aniba rosaeodora), na Amazônia Central resumo o Pau-rosa (Aniba rosaeodora Ducke, lauraceae) é uma árvore amazônica fonte do mais puro linalol, o qual é o principal componente do seu óleo essencial e muito valioso no mercado internacional de perfumaria. após várias décadas de intensa exploração, a espécie foi levada à categoria de ameaçada de extinção. Quatro populações naturais distribuídas na bacia amazônia Central foram avaliadas quanto ao nível e a distribuição da diversidade genética. trinta e cinco marcadores RaPD reprodutíveis foram gerados, dos quais 32 foram polimórficos (91,4%). a diversidade foi maior dentro das populações (76,5%; p < 0,0001) e a distribuição geográfica contribuiu para a diferenciação entre as populações (23,4%; p < 0,0001). a amova indicou que pode haver uma influência parcial do Rio amazonas no fluxo gênico (3,3%; p < 0,0001), mas foram identificadas evidências de fluxo gênico atravessando o rio. Houve diferenças significativas nas freqüências dos marcadores (p < 0,05) e o fluxo gênico estimado foi relativamente baixo (Nm = 2,02). a correlação entre a distância genética e o fluxo gênico foi de -0,95 (p = 0,06) e para a distância geográfica e o fluxo gênico foi de -0,78 (p = 0,12). Houve um padrão geográfico de variabilidade ao longo do eixo leste -oeste, influenciado também pelo Rio amazonas, o que sugere que o rio poderia funcionar como uma barreira para o fluxo gênico. apesar de ameaçadas, estas populações de Pau-rosa possuem alta diversidade, com o maior valor na população de manaus, que vem sendo prot...

No abstract

O Pau-rosa (Aniba rosaeodora Ducke) é uma espécie importante economicamente para a Região Amazônica, porque sua madeira é fonte de linalol, insumo utilizado pelas perfumarias. Esta espécie foi explorada durante décadas e, ainda assim, o conhecimento acerca da diversidade genética intra-específica é muito restrito. Foram objetivos deste trabalho: 1) validar um protocolo para coleta de folhas de pau-rosa que permitisse preservar a integridade do DNA até a estocagem em "freezer"; 2) selecionar um protocolo para extração de DNA em quantidade e qualidade adequadas para geração de bandas RAPD e 3) desenvolver um critério para avaliar o grau de reprodutibilidade que pudesse auxiliar a seleção de bandas RAPD úteis para análises de diversidade genética. Imediatamente após a coleta, as folhas foram acondicionadas em tubos de polietileno com sílica gel e aí permaneceram por até 10 dias. Foram testados três protocolos para a extração de ácidos nucléicos destas folhas, condições ideais para as PCR e a reprodutibilidade dos padrões RAPD. Critérios para a eliminação das bandas que mais contribuíram para o afastamento dos resultados do ideal da reprodutibilidade total foram desenvolvidos e a significância estatística das diferenças geradas pela aplicação dos critérios ao conjunto de dados foi testada. DNA com qualidade e em quantidade suficiente para a geração de padrões RAPD, nas condições ideais definidas para as PCRs, foi obtido. A eliminação de bandas com reprodutibilidade menor que 70% não diferiu do controle. A eliminação de bandas com reprodutibilidade menor que 90% diferiu dos demais tratamentos em todos os arranjos testados (P < 5%).

ABSTRACT. Fusarium oxysporum f. sp cubense (Foc), the causal agent of Panama disease, is responsible for economic losses in banana crops worldwide. The identification of genes that effectively act on pathogenicity and/or virulence may contribute to the development of different strategies for disease control and the production of resistant plants. The objective of the current study was to analyze the importance of SGE1 gene expression in Foc virulence through post-transcriptional silencing using a double-stranded RNA hairpin. Thirteen transformants were selected based on different morphological characteristics, and sporulation in these transformants was significantly reduced by approximately 95% (P < 0.05) compared to that of the wild-type strain. The relative SGE1 expression levels in the transformant strains were reduced by 27 to 47% compared to those in the wild-type strain. A pathogenicity analysis revealed that the transformants were able to reach the rhizomes and pseudostems of the inoculated banana plants. However, the transformants induced initial disease symptoms in the banana plants approximately 10 days later than that by the wild-type Foc, and initial disease symptoms persisted even at 45 days after inoculation. These results indicate that the SGE1 gene is directly involved in the virulence of Foc. Therefore, SGE1 may be a potential candidate for host-induced gene silencing in banana plants.

ABSTRACT. Chromobacterium violaceum is a Gram-negative proteobacteria found in water and soil; it is widely distributed in tropical and subtropical regions, such as the Amazon rainforest. We examined protein expression changes that occur in C. violaceum at different growth temperatures using electrophoresis and mass spectrometry. The total number of spots detected was 1985; the number ranged from 99 to 380 in each assay. The proteins that were identified spectrometrically were categorized as chaperones, proteins expressed exclusively under heat stress, enzymes involved in the respiratory and fermentation cycles, ribosomal proteins, and proteins related to transport and secretion. Controlling inverted repeat of chaperone expression and inverted repeat DNA binding sequences, as well as regions recognized by sigma factor 32, elements involved in the genetic regulation of the bacterial stress response, were identified in the promoter regions of several of the genes coding proteins, involved in the C. violaceum stress response. We found that 30°C is the optimal growth temperature for C. violaceum, whereas 25, 35, and 40°C are stressful temperatures that trigger the expression of chaperones, superoxide dismutase, a probable small heat shock protein, a probable phasing, ferrichrome-iron receptor protein, elongation factor P, and an ornithine carbamoyltransferase catabolite. This information improves our comprehension of the mechanisms involved in stress adaptation by C. violaceum.

Microsatellite markers were developed for Dicksonia sellowiana (Dicksoniaceae), an overexploited and endangered tree-fern species native to Brazil. From an enriched genomic library, 11 primer pairs were selected and used to characterize 36 D. sellowiana individuals from six Brazilian populations. Eight primer pairs amplified dinucleotide and hexanucleotide repeats with two to ten alleles per locus; three primer pairs were monomorphic. For the set of polymorphic markers, the mean observed and expected heterozygosity ranged from 0.29 to 0.44 and from 0.27 to 0.56, respectively. Eight of the primer pairs were also successfully amplified for Cyathea vestita (Cyatheaceae). These molecular markers can be useful tools for genetic studies aiming to analyze the impact of deforestation and overexploitation on the population structure and genetic diversity of fern species from various botanical families.

-The hybridization between oil palm (Elaeis guineensis)