Genetic diversity of the species Cnesterodon hypselurus (Cyprinodontiformes: Poeciliidae) in Cinzas River basin: new record and headwater capture evidences

Cnesterodon hypselurus is a small fish that has a restricted distribution in southern Brazil, including headwaters of the Tibagi and Itararé river basins (Upper Paraná River). This study reported C. hypselurus in a headwater of Cinzas River basin, where there were no previous records of this species, and employed microsatellite loci and mitochondrial haplotypes in a population genetic analysis. A total of 57 specimens was analyzed, including 30 from Cinzas River basin, 25 from Itararé River basin and two from Tibagi River basin. Results indicated low genetic diversity levels (HE = 0.334 and h = 0.246) for the sample from Cinzas River, suggesting reflections of a founder effect after the species had dispersed from one watershed to another, possibly by headwater captures. Since different populations were detected between the Cinzas and Itararé rivers (DEST = 0.248, P-value < 0.05) and other occurrence sites are still unknown in the Cinzas River basin, the data herein have great relevance and should be taken into account in future management and conservation actions, as well as in evolutionary studies of C. hypselurus.(AU)

Cnesterodon hypselurus é um pequeno peixe que possui distribuição restrita no sul do Brasil, incluindo cabeceiras das bacias dos rios Tibagi e Itararé (alto rio Paraná). Este estudo reportou C. hypselurus na cabeceira da bacia do rio das Cinzas, onde não havia registros prévios desta espécie, e empregou locos microssatélites e haplótipos mitocondriais em uma análise genética de populações. Um total de 57 espécimes foi analisado, incluindo 30 do rio das Cinzas, 25 da bacia do rio Itararé e dois da bacia do rio Tibagi. Os resultados indicaram baixos níveis de diversidade genética (HE = 0,334 e h = 0,246) para a amostra do rio das Cinzas, sugerindo reflexos de um efeito fundador após a espécie ter dispersado de uma bacia para a outra, possivelmente a partir de captura de cabeceiras. Uma vez que diferentes populações foram detectadas entre os rios das Cinzas e Itararé (DEST = 0,248, valor de P < 0,05) e que outros pontos de ocorrência ainda são desconhecidos na bacia do rio das Cinzas, os dados do presente estudo mostram grande relevância e deveriam ser considerados em futuras ações de manejo e conservação, bem como em estudos evolutivos de C. hypselurus.(AU)

Genetic connectivity in the spotted rose snapper Lutjanus guttatus (Lutjaniformes: Lutjanidae) between Mexico and Panama throughout the Tropical Eastern Pacific

The spotted rose snapper, Lutjanus guttatus, is an important fishery species with high potential for aquaculture. Genetic characterization of its natural populations is necessary to avoid stock collapse and loss of genetic diversity. Previous studies carried out in the Tropical Eastern Pacific (TEP), however, have shown contrasting results in the genetic structure of fish populations, particularly in species of Lutjanidae. Therefore, to understand the genetic structure of spotted rose snapper in the TEP, twelve microsatellite loci were used to assess the genetic diversity and explore the hypothesis of population genetic structure in samples of the species collected throughout the TEP. Fin clips from 186 sampled individuals (27 to 49 per site) were analyzed from five sites in the three regional biogeographic provinces, delimited by shoreline reef habitat breaks: La Paz (Cortez province), Colima and Oaxaca (Mexican province), Chiriqui and Port of Panama (Panamic province). Results of global Analysis of Molecular Variance (AMOVA), population pairwise FST, hierarchical AMOVA, and a discriminant analysis of principal components (DAPC) reflected a panmictic population involving the entire set of sampled sites. The role of larval dispersal, post-recruitment migration, and marine current dynamics as drivers of genetic connectivity in this species is discussed.(AU)

Genetic structure simulation for Hancornia speciosa populations in Northeast Brazil / Simulação da estrutura genética de populações de Hancornia speciosa no nordeste brasileiro

ABSTRACT: Mangaba tree is a fruit tree species whose natural populations are fragmented by anthropic actions. For this reason, studies assessing the impact of fragmentation on the diversity and genetic structure of these populations are required in order to establish suitable conservation strategies. In our study, we used data from analyzes through microsatellite markers in computer simulations to estimate the rates of migration and selfing of six mangaba populations. The studied populations are located in the northeastern states of Ceará, Pernambuco and Sergipe. We tested different selfing and migration rates and selected the combination that showed values of observed and expected heterozygosity closest to those previously obtained with microsatellite markers. According to our simulations, selfing and migration were moderate. This may have led to an increase in inbreeding and genetic drift, resulting in low genetic diversity. We recommend expanding the area and reducing disturbance to promote the occurrence of pollinators, which play an important role in increasing genetic diversity.

RESUMO: A mangabeira é uma espécie frutífera cujas populações naturais se encontram fragmentadas por ações antrópicas. Desse modo, são necessários estudos sobre a avaliação do impacto da fragmentação sobre a diversidade e estrutura genética dessas populações para o estabelecimento de estratégias de conservação adequadas. No presente estudo, foram utilizados dados de análises com marcadores microssatélites em simulações computacionais para estimar as taxas de migração e autofecundação de seis populações de mangaba. As populações estudadas estão localizadas nos estados nordestinos do Ceará, Pernambuco e Sergipe. Foram testadas diferentes taxas de autofecundação e migração, e selecionada a combinação que apresentou valores de heterozigosidade observada e esperada mais próximos dos obtidos com marcadores microssatélites. Com base nas simulações, a autofecundação foi de 0,3 e a taxa de migração variou de 0,5 a 0,6, valores que podem ter conduzido ao aumento da endogamia e deriva genética, resultando em baixa diversidade genética. Recomenda-se a expansão da área e a redução de perturbações para promover a ocorrência de polinizadores, que desempenham um papel importante no aumento da diversidade genética.

Genetic structure simulation for Hancornia speciosa populations in Northeast Brazil / Simulação da estrutura genética de populações de Hancornia speciosa no nordeste brasileiro

Mangaba tree is a fruit tree species whose natural populations are fragmented by anthropic actions. For this reason, studies assessing the impact of fragmentation on the diversity and genetic structure of these populations are required in order to establish suitable conservation strategies. In our study, we used data from analyzes through microsatellite markers in computer simulations to estimate the rates of migration and selfing of six mangaba populations. The studied populations are located in the northeastern states of Ceará, Pernambuco and Sergipe. We tested different selfing and migration rates and selected the combination that showed values of observed and expected heterozygosity closest to those previously obtained with microsatellite markers. According to our simulations, selfing and migration were moderate. This may have led to an increase in inbreeding and genetic drift, resulting in low genetic diversity. We recommend expanding the area and reducing disturbance to promote the occurrence of pollinators, which play an important role in increasing genetic diversity.

A mangabeira é uma espécie frutífera cujas populações naturais se encontram fragmentadas por ações antrópicas. Desse modo, são necessários estudos sobre a avaliação do impacto da fragmentação sobre a diversidade e estrutura genética dessas populações para o estabelecimento de estratégias de conservação adequadas. No presente estudo, foram utilizados dados de análises com marcadores microssatélites em simulações computacionais para estimar as taxas de migração e autofecundação de seis populações de mangaba. As populações estudadas estão localizadas nos estados nordestinos do Ceará, Pernambuco e Sergipe. Foram testadas diferentes taxas de autofecundação e migração, e selecionada a combinação que apresentou valores de heterozigosidade observada e esperada mais próximos dos obtidos com marcadores microssatélites. Com base nas simulações, a autofecundação foi de 0,3 e a taxa de migração variou de 0,5 a 0,6, valores que podem ter conduzido ao aumento da endogamia e deriva genética, resultando em baixa diversidade genética. Recomenda-se a expansão da área e a redução de perturbações para promover a ocorrência de polinizadores, que desempenham um papel importante no aumento da diversidade genética.

Genetic structure analysis of Mauritia flexuosa natural population from the Lençóis Maranhenses region using microsatellite markers

Buriti (Mauritia flexuosa L.f), a palm tree native to South America and widely distributed in Brazil, displays significant ecological, economic and biotechnological importance. However, the disorderly extractivism and environmental degradation of its endemic areas are leading to reductions in, and/or extinction of the buriti palm tree, causing ecological imbalance with significant economic losses for rural communities and genetic diversity. Consequently, populational genetic diversity studies have become relevant as a strategy for conserving the species. Therefore, this study evaluated the genetic structure of 10 populations from the Lençóis Maranhenses region, in the state of Maranhão, Brazil, using microsatellite markers. Results indicated that eight pairs displayed a high level of polymorphism in the populations evaluated (98.5 %). The genetic diversity estimations allowed for identifying 220 alleles (average of 9.5 alleles/loci), and the heterozygosity averages observed (Ho) were lower than the heterozygosity expected (He) in the population (0.16 and 0.64) and loci levels (0.15 and 0.65), respectively. The Shannon Index (I) mean value of 1.36 indicated high diversity and genotypic richness in the populations evaluated, while the population index (FST) indicated a low value (0.05) and the fixation index pertaining to individuals indicated a high value (FIS = 0.79) exhibiting a moderate population distribution structure, and pointing to greater diversity between individuals. Based on these results, populations denominated as PA and PB presented a high genetic similarity (0.219), while populations denominated as PF and PJ exhibited more distant genetic characteristics (0.519). These results can be correlated based on prioritization of conservation of this non­domesticated species, influenced by environmental characteristics, suggesting that the genetic diversity found should be conserved in a germplasm bank, and subsequently exploited in breeding programs.(AU)

Transferability of microssatellite markers to Trichogramma pretiosum Riley, 1879 (Hymenoptera: Trichogrammatidae) / Transferibilidade de marcadores microssatélites para Trichogramma pretiosum Riley, 1879 (Hymenoptera: Trichogrammatidae)

The biological pest control has expanded in Brazil with the Trichogramma pretiosumas the main natural enemy. The microsatellite molecular markers Simple Sequence Repeat (SSR) have been the most used, as they are multiallelic, robust and reproducible, in several species. In order to optimize future processes of identification and analysis of the parasitoid's genetic diversity, twenty markers, isolated and characterized for the parasitoid wasp Trichogramma dendrolimi,were tested in 15 generations of T. pretiosum. Those markers, ten have been transferred and can be used to evaluate the genetic variation of T. pretiosum.(AU)

O controle biológico de pragas tem expandido no Brasil com o Trichogramma pretiosumcomo o principal inimigo natural. Os marcadores moleculares microssatélites de repetição de sequência simples (SSR) temsido os mais utilizados, por serem multialélicos, robustos e reprodutíveis, em várias espécies. No intuito de otimizar futuros processos de identificação e análise de diversidade genética do parasitoide, 20marcadores, isolados e caracterizados para a vespa parasitoide Trichogramma dendrolimi, foram testados em 15 gerações de T. pretiosum. Destes marcadores, dez foram transferidos e podem ser utilizados para avaliar a variação genética de T. pretiosum.(AU)

Combining disease resistance and postharvest quality traits by early marker-assisted backcrossing in carioca beans

Common bean is a worldwide important crop. The development of varieties with durable resistance to diseases is a major challenge in common bean breeding. The present study aimed at evaluating the phenotypic and molecular selection of anthracnose resistance in a population obtained by assisted backcrossing from IAC Formoso (resistant, donor parent) × BRS Pérola (susceptible, recurrent parent). Nine microsatellites (SSRs) and one Sequence Tagged Sites (STS) markers previously linked to ANT resistance were used to genotype this progeny, and the results showed that the selection of the genotypes closest to the donor parent in the BC1F1 population decreased the number of backcrossing cycles necessary to obtain advanced isogenic lines, potentiating the use of this tool for early selection of resistant cultivars. A total of 31 % of the BC1F1 progeny was selected and backcrossed again. The progeny derived from the second backcross (BC2F3) was selected for the Carioca grain ideotype, and 42 % of the genotypes showed high resistance to anthracnose under controlled conditions of infection for races 65 and 81. Superior resistant plants were selected and evaluated under natural conditions of infection to fusarium wilt and angular leaf spot, allowing the selection of two inbred lines with higher resistance to anthracnose, fusarium wilt, angular leaf spot and postharvest quality traits such as yield, 100 seed weight, L value at seed harvest grain darkening and cooking time. The approach outlined in this paper proved to be effective to simultaneously select for disease resistance without losing technological quality aspects of the bean.

Genetic structure analysis of Mauritia flexuosa natural population from the Lençóis Maranhenses region using microsatellite markers

Buriti (Mauritia flexuosa L.f), a palm tree native to South America and widely distributed in Brazil, displays significant ecological, economic and biotechnological importance. However, the disorderly extractivism and environmental degradation of its endemic areas are leading to reductions in, and/or extinction of the buriti palm tree, causing ecological imbalance with significant economic losses for rural communities and genetic diversity. Consequently, populational genetic diversity studies have become relevant as a strategy for conserving the species. Therefore, this study evaluated the genetic structure of 10 populations from the Lençóis Maranhenses region, in the state of Maranhão, Brazil, using microsatellite markers. Results indicated that eight pairs displayed a high level of polymorphism in the populations evaluated (98.5 %). The genetic diversity estimations allowed for identifying 220 alleles (average of 9.5 alleles/loci), and the heterozygosity averages observed (Ho) were lower than the heterozygosity expected (He) in the population (0.16 and 0.64) and loci levels (0.15 and 0.65), respectively. The Shannon Index (I) mean value of 1.36 indicated high diversity and genotypic richness in the populations evaluated, while the population index (FST) indicated a low value (0.05) and the fixation index pertaining to individuals indicated a high value (FIS = 0.79) exhibiting a moderate population distribution structure, and pointing to greater diversity between individuals. Based on these results, populations denominated as PA and PB presented a high genetic similarity (0.219), while populations denominated as PF and PJ exhibited more distant genetic characteristics (0.519). These results can be correlated based on prioritization of conservation of this non–domesticated species, influenced by environmental characteristics, suggesting that the genetic diversity found should be conserved in a germplasm bank, and subsequently exploited in breeding programs.

Combining disease resistance and postharvest quality traits by early marker-assisted backcrossing in carioca beans

Common bean is a worldwide important crop. The development of varieties with durable resistance to diseases is a major challenge in common bean breeding. The present study aimed at evaluating the phenotypic and molecular selection of anthracnose resistance in a population obtained by assisted backcrossing from IAC Formoso (resistant, donor parent) × BRS Pérola (susceptible, recurrent parent). Nine microsatellites (SSRs) and one Sequence Tagged Sites (STS) markers previously linked to ANT resistance were used to genotype this progeny, and the results showed that the selection of the genotypes closest to the donor parent in the BC1F1 population decreased the number of backcrossing cycles necessary to obtain advanced isogenic lines, potentiating the use of this tool for early selection of resistant cultivars. A total of 31 % of the BC1F1 progeny was selected and backcrossed again. The progeny derived from the second backcross (BC2F3) was selected for the Carioca grain ideotype, and 42 % of the genotypes showed high resistance to anthracnose under controlled conditions of infection for races 65 and 81. Superior resistant plants were selected and evaluated under natural conditions of infection to fusarium wilt and angular leaf spot, allowing the selection of two inbred lines with higher resistance to anthracnose, fusarium wilt, angular leaf spot and postharvest quality traits such as yield, 100 seed weight, L value at seed harvest grain darkening and cooking time. The approach outlined in this paper proved to be effective to simultaneously select for disease resistance without losing technological quality aspects of the bean.

Temporal genetic structure of a stock of Prochilodus lineatus (Characiformes: Prochilodontidae) in the Mogi-Guaçu River ecosystem, São Paulo, Brazil

Prochilodus lineatus is a species of migratory fish widely distributed in the Paraná River basin, found mainly in the Grande, Pardo and Mogi-Guaçu rivers located in a well-developed region of the state of São Paulo. This study analyzes the genetic diversity and population structure in shoals of P. lineatus based on temporal analysis of specimens sampled over the years 2003, 2005, 2006, 2009, 2010, and 2015 in the Mogi-Guaçu River, São Paulo, at the region of Cachoeira de Emas. Genetic analysis performed using the D-Loop and seven microsatellite marker revealed significant genetic variability in all sampled groups. Moderate levels of structuring between groups were identified with the microsatellite markers (Fst = 0.14), while the mitochondrial marker did not reveal patterns of genetic structuring (Fst = 0.01). The genetic variability fluctuated over time, characterizing patterns of structuring among the analyzed samples. The occurrence of environmental alterations resulting in increased mortality rates, as well as changes in the water level in the ecosystem, among other factors, could determine changes in the reproductive behavior of species. The lack of favorable environmental conditions for reproduction in the basin, as reflected by tests of population bottlenecks, could have resulted in the differentiation of populations of P. lineatus over time.(AU)

Prochilodus lineatus é uma espécie de peixe migratório amplamente distribuído na bacia do rio Paraná, principalmente nos rios Grande, Pardo e Mogi-Guaçu localizados em uma região bem desenvolvida do estado de São Paulo. Este estudo analisou a diversidade genética e a estrutura populacional em cardumes de P. lineatus com base na análise temporal de espécimes amostrados ao longo dos anos de 2003, 2005, 2006, 2009, 2010 e 2015 na Cachoeira de Emas no rio Mogi-Guaçu, São Paulo, Brasil. A análise genética realizada com o marcador D-Loop e sete microssatélites revelou variabilidade genética significativa em todos os grupos amostrados. Níveis moderados de estruturação entre os grupos foram identificados com os marcadores microssatélites (Fst = 0.14), enquanto o marcador mitocondrial não revelou padrões de estruturação genética (Fst = 0.01). A variabilidade genética identificada no estoque oscilou ao longo do tempo, caracterizando padrões de estruturação entre as amostras analisadas. A ocorrência de alterações ambientais resultando em aumento das taxas de mortalidade, bem como mudanças no nível de água no ecossistema, entre outros fatores, podem determinar mudanças no comportamento reprodutivo das espécies. A falta de condições ambientais favoráveis para a reprodução na bacia, pode ter resultado na diferenciação das populações de P. lineatus ao longo do tempo.(AU)

Analysis of the genetic diversity of Dragon fruit based on ISSR markers in Colombia / Análise da diversidade genética da fruta do dragão com base em marcadores ISSR na Colômbia

Selenicereus megalanthus H. is a tropical fruit belonging to the family Cactaceae, is rich in essential nutrients, antioxidants and bioactive components. It presents wide variability in different characteristics and a great demand in the market; however, genetic studies in Colombia are scarce. The main of this study was to characterize the genetic diversity of 76 yellow pitahaya genotypes with eight ISSR markers. Genetic parameters expected average heterozygosity (He), percentage of polymorphic loci, genetic distances and Fst were estimated with TFPGA. The analysis of the population genetic structure was carried out with the STRUCTURE 2.3.4. As a result, 225 alleles were generated and the number of polymorphic loci ranged 85 (CT, AG) to 90 (GT). High genetic diversity was found, with an average value of heterozygosity was 0.34 with a genetic differentiation coefficient (Fst) of 0.26, indicating that there was a great genetic diversity, similar values than those reported in other studies of pitahaya genetic diversity in Colombia. The 76 genotypes were grouped into K=3 according to geographic location, however, in some groups a mixture of individuals from different origins was observed. The analysis of molecular variance (AMOVA) showed higher variation (75%) within groups than among groups (25%). These results provide information that can be used to develop conservation strategies for dragon fruit and breeding programs to obtain more productive pitahaya genotypes with superior quality, high yield and with resistance to biotic and abiotic factors.

Selenicereus megalanthus H. é uma fruta tropical pertencente à família Cactaceae, rica em nutrientes essenciais, antioxidantes e componentes bioativos. Apresenta grande variabilidade em diferentes características e uma grande demanda no mercado; no entanto, os estudos genéticos na Colômbia são escassos. O principal deste estudo foi caracterizar a diversidade genética de 76 genótipos de pitahaya amarela com oito marcadores ISSR. Parâmetros genéticos esperados de heterozigosidade média (He), porcentagem de locos polimórficos, distâncias genéticas e Fst foram estimados com TFPGA. A análise da estrutura genética da população foi realizada com a ESTRUTURA 2.3.4. Como resultado, 225 alelos foram gerados e o número de loci polimórficos variou de 85 (CT, AG) a 90 (GT). Foi encontrada alta diversidade genética, com um valor médio de heterozigosidade de 0,34 com coeficiente de diferenciação genética (Fst) de 0,26, indicando que havia uma grande diversidade genética, valores semelhantes aos relatados em outros estudos de diversidade genética de pitahaya na Colômbia. Os 76 genótipos foram agrupados em K = 3 de acordo com a localização geográfica, porém, em alguns grupos foi observada uma mistura de indivíduos de diferentes origens. A análise de variância molecular (AMOVA) mostrou maior variação (75%) dentro dos grupos do que entre os grupos (25%). Esses resultados fornecem informações que podem ser utilizadas para desenvolver estratégias de conservação da fruta do dragão e programas de melhoramento para a obtenção de genótipos de pitahaya mais produtivos, com qualidade superior, alto rendimento e com resistência a fatores bióticos e abióticos.

Genetic comparison of populations of Piaractus brachypomus and P. orinoquensis (Characiformes: Serrasalmidae) of the Amazon and Orinoco basins

Recently, the large migratory fishes of the family Serrasalmidae (Piaractus brachypomus and P. orinoquensis) were described as restricted to the Orinoco and Amazon basins. Both species provide important ecosystem services. They also are an important fisheries resource, which has caused that their populations have decreased in recent years. National fisheries policies still consider both species as one, which leads to inefficiencies in their management and conservation. The aim of this study was to genetically characterize these two species, using microsatellite and mitochondrial markers, and discuss the implication of these results for conservation and management. We found that both species have moderate genetic diversity and varied patterns of genetic distribution in the fluvial landscape. Piaractus brachypomus presented genetic diversity of A=6.5; He=0.72; Ho=0.67; H=1.000; á´«=0.0092, three management units related to the evolutionary process of the Amazon basin and the effective sizes of local populations were smaller compared to P. orinoquensis, which presented genetic diversity of A=6.1; He=0.66; Ho=0.55; H=0.968; á´«=0.010 and comprises only one management unit. These results demonstrate the need to design management policies that focus on species and geographically restricted populations.

Recientemente, los grandes peces migratorios Serrasalmidae (Piaractus brachypomus y P. orinoquensis) fueron diferenciados en las cuencas del Orinoco y Amazonas. Ambas especies brindan importantes servicios ecosistémicos, entre ellos la pesca para la dieta humana, lo que ha provocado que sus poblaciones hayan disminuido en los últimos años. Las políticas pesqueras nacionales aún consideran a ambas especies como una sola, lo que conduce a ineficiencias en su gestión y conservación. El objetivo de este estudio fue caracterizar genéticamente estas dos especies de Piaractus, usando marcadores microsatélites y mitocondriales, y discutir la implicación de estos resultados para la conservación y el manejo. Encontramos que ambas especies tienen una diversidad genética moderada y patrones variados de distribución genética en el paisaje fluvial. Piaractus brachypomus presentó diversidad genética de A=6.5; He=0.72; Ho=0.67; H=1.000; á´«=0.0092, tres unidades de manejo relacionadas con el proceso evolutivo de la cuenca Amazónica y los tamaños efectivos de las poblaciones locales fueron menores en comparación con P. orinoquensis, que presentó diversidad genética de A=6.1; He=0.66; Ho=0.55; H=0.968; á´«=0,010 y comprende una sola unidad de gestión. Estos resultados demuestran la necesidad de diseñar políticas de manejo que se enfoquen en especies y poblaciones geográficamente restringidas.

Diagnostic locus for identification of silverside hybrids (Odontesthes humensis and Odontesthes bonariensis) in a natural population / Locus diagnóstico para identificação de híbridos de peixe-rei (Odontesthes humensis and Odontesthes bonariensis) em população natural

Hybridization is a natural phenomenon that occurs more often in fish than in other vertebrates. The use of nuclear and mitochondrial molecular markers provides valuable results in the detection of these events. The aim of this study was to investigate the occurrence of interspecific hybrids in natural populations of silverside. The samples of Odontesthes humensis, Odontesthes bonariensis, and indivi-duals that were morphologically different from pure species were collected in the Mangueira lagoon, located in southern Brazil. Result: Six tetranucleotide microsatellite loci were synthesized and tested. The UFPEL_OH3 locus proved to be diagnostic for the detection of silverside hybrids, and it was possi-ble to distinguish between pure and hybrid species. The mitochondrial marker gene cytb synthesized from conserved Odontesthes sequences in the GenBank genetic database showed no differences in the genetic sequence of the samples, needing further studies to confirm the hypothesis.(AU)

A hibridação é um fenômeno natural que ocorre mais frequentemente em peixes do que em outros vertebrados. Para detectá-la, são utilizados marcadores moleculares nucleares e mitocondriais, os quais fornecem resultados valiosos. O objetivo deste estudo foi investigar a ocorrência de híbridos in-terespecíficos em populações naturais de peixe-rei. As amostras de Odontesthes humensis, Odontesthes bonariensis e de indivíduos morfologicamente diferentes das espécies puras foram coletadas na lagoa Mangueira, localizada no Sul do Brasil. Foram sintetizados e testados seis loci microssatélites tetranu-cleotídeos. O locus UFPEL_OH3 mostrou-se um diagnóstico para detectar híbridos de peixe-rei, pos-sibilitando a distinção de espécies puras de híbridas. O marcador mitocondrial gene cytb, sintetizado com base nas sequências conservadas de Odontesthes no banco de dados genéticos do GenBank, não apresentou diferenças na sequência genética das amostras, portanto, são necessários mais estudos para confirmar a hipótese de hibridação.(AU)

Molecular profiling of bacterial blight resistance in Malaysian rice cultivars / Perfil molecular da resistência à ferrugem bacteriana em cultivares de arroz da Malásia

Bacteria blight is one of the most serious bacterial diseases of rice worldwide. The identification of genetic potential against bacterial blight in the existing rice resources is a prerequisite to develop multigenic resistance to combat the threat of climate change. This investigation was conducted to evaluate alleles variation in 38 Malaysian cultivars using thirteen Simple Sequences Repeats markers and one Sequence Tagged Sites (STS) marker which were reported to be linked with the resistance to bacterial blight. Based on molecular data, a dendrogram was constructed which classified the rice cultivars into seven major clusters at 0.0, 0.28 and 0.3 of similarity coefficient. Cluster 5 was the largest group comprised of ten rice cultivars where multiple genes were identified. However, xa13 could not be detected in the current rice germplasm, whereas xa2 was detected in 25 cultivars. Molecular analysis revealed that Malaysian rice cultivars possess multigenic resistance.

A ferrugem bacteriana é uma das doenças bacterianas mais graves do arroz em todo o mundo. A identificação do potencial genético contra a ferrugem bacteriana nos recursos de arroz existentes é um pré-requisito para desenvolver resistência multigênica no combate à ameaça da mudança climática. Esta investigação foi conduzida para avaliar a variação de alelos em 38 cultivares da Malásia usando 13 marcadores Simple Sequences Repeats (SSR) e 1 marcador Sequence Tagged Sites (STS), que foram relatados como associados à resistência à ferrugem bacteriana. Com base em dados moleculares, foi construído um dendrograma que classificou as cultivares de arroz em sete grandes agrupamentos a 0,0, 0,28 e 0,3 de coeficiente de similaridade. O Cluster 5 foi o maior grupo composto por 10 cultivares de arroz, no qual múltiplos genes foram identificados. No entanto, xa13 não pôde ser detectado no germoplasma atual de arroz, enquanto xa2 foi detectado em 25 cultivares. A análise molecular revelou que as cultivares de arroz da Malásia possuem resistência multigênica.

Combining disease resistance and postharvest quality traits by early marker-assisted backcrossing in carioca beans

ABSTRACT: Common bean is a worldwide important crop. The development of varieties with durable resistance to diseases is a major challenge in common bean breeding. The present study aimed at evaluating the phenotypic and molecular selection of anthracnose resistance in a population obtained by assisted backcrossing from IAC Formoso (resistant, donor parent) × BRS Pérola (susceptible, recurrent parent). Nine microsatellites (SSRs) and one Sequence Tagged Sites (STS) markers previously linked to ANT resistance were used to genotype this progeny, and the results showed that the selection of the genotypes closest to the donor parent in the BC1F1 population decreased the number of backcrossing cycles necessary to obtain advanced isogenic lines, potentiating the use of this tool for early selection of resistant cultivars. A total of 31 % of the BC1F1 progeny was selected and backcrossed again. The progeny derived from the second backcross (BC2F3) was selected for the Carioca grain ideotype, and 42 % of the genotypes showed high resistance to anthracnose under controlled conditions of infection for races 65 and 81. Superior resistant plants were selected and evaluated under natural conditions of infection to fusarium wilt and angular leaf spot, allowing the selection of two inbred lines with higher resistance to anthracnose, fusarium wilt, angular leaf spot and postharvest quality traits such as yield, 100 seed weight, L value at seed harvest grain darkening and cooking time. The approach outlined in this paper proved to be effective to simultaneously select for disease resistance without losing technological quality aspects of the bean.

Outbreak of toxoplasmosis associated with muscular lesions in finishing pigs caused by an atypical Toxoplasma gondii genotype / Surto de toxoplasmose associado a lesões musculares em suínos de terminação causado por um genótipo atípico de T. gondii

Toxoplasma gondii infections are usually asymptomatic in pigs, and an acute clinical disease is rare in this host. This study aimed to determine the pathological and molecular aspects of an outbreak of fatal systemic toxoplasmosis in finishing pigs in Brazil. The outbreak occurred on a commercial finishing pig farm in the state of Santa Catarina in southern Brazil. The farm had 1500 pigs and 3.8% of mortality rate during the outbreak. The pigs had fever, anorexia, apathy, and locomotor deficits. Seven pigs were necropsied. Gross findings included multifocal to coalescent pale areas in skeletal muscles, lymphadenomegaly, hepatosplenomegaly, and non-colapsed lungs. The histological findings included granulomatous lymphadenitis, hepatitis and splenitis, necrotizing myositis, and lymphoplasmacytic interstitial pneumonia. Lung and liver lesions were occasionally accompanied by T. gondii parasitic structures. Positive immunolabeling for T. gondii tachyzoites and encysted bradyzoites was detected in all examined pigs. PCR-RFLP (11 markers) and microsatellite analysis (15 markers) identified the non-archetypal genotype #278 in pigs. This is the first report of systemic toxoplasmosis in pigs with muscle lesions and additionally shows the diversity of disease-causing T. gondii genotypes circulating in animals in Brazil.(AU)

As infecções por Toxoplasma gondii são geralmente assintomáticas em suínos, e uma doença clínica aguda é rara nessa espécie. Este estudo teve como objetivo determinar os aspectos patológicos e moleculares de um surto de toxoplasmose sistêmica fatal em suínos em terminação no Brasil. O surto ocorreu em uma granja comercial de suínos em terminação no estado de Santa Catarina, no sul do Brasil. A granja tinha 1500 suínos e a taxa de mortalidade durante o surto foi de 3,8%. Os suínos apresentaram febre, anorexia, apatia e déficits locomotores. Sete suínos foram necropsiados. Os achados macroscópicos incluíram áreas pálidas multifocais a coalescentes nos músculos esqueléticos, linfadenomegalia, hepatoesplenomegalia e pulmões não colapsados. Os achados histológicos incluíram linfadenite, hepatite, esplenite granulomatosa e miosite necrosante, assim como pneumonia intersticial linfoplasmocítica. Lesões pulmonares e hepáticas foram ocasionalmente acompanhadas por estruturas parasitárias de T. gondii. A imunomarcação positiva para taquizoítos e bradizoítos encistados de T. gondii foi observada em todos os suínos examinados. PCR-RFLP (11 marcadores) e análise de microssatélites (15 marcadores) identificaram o genótipo não arquetípico #278 em suínos. Este é o primeiro relato de toxoplasmose sistêmica em suínos com lesões musculares e, adicionalmente, demonstra a diversidade de genótipos de T. gondii causadores de doenças circulantes em animais no Brasil.(AU)

Técnicas biomoleculares aplicadas em hospedeiros intermediários da esquistossomose / Biomolecular techniques applied to intermediate hosts of Schistosomiasis

A esquistossomose é uma doença parasitária acometida por milhões de pessoas no mundo. Essa parasitose é transmitida por caramujos que servem de hospedeiros intermediários de helmintos digenéticos. A identificação correta das espécies transmissoras pode auxiliar no conhecimento epidemiológico da doença. Contudo, métodos convencionais de classificação podem ter resultado duvidoso, devido à variação intraespecífica entre os espécimes. Em virtude disso, esta revisão teve como objetivo descrever as principais técnicas moleculares que podem ser aplicadas, assim como o aprimoramento dos métodos ao longo do tempo. A PCR é uma técnica desenvolvida através da polimerização de DNA em cadeia realizada in vitro, onde se amplifica o DNA em múltiplas cópias, por replicação enzimática, sem necessidade de um organismo vivo. Na PCR, em tempo real, as fases de amplificação, detecção e quantificação são totalmente automatizadas, ocorrendo em simultâneo. Com a evolução da técnica convencional, foi surgindo a Proteína C Reativa ­ Polimorfismo de Comprimento de Fragmento de Restrição (PCR-RFLP), os microssatélites, e a PCR-RAPD. Através dessas variantes foi possível classificar, com precisão, as espécies transmissoras, fazer as análises da variabilidade genética intraespecífica e ampliar os estudos filogenéticos das populações. O conhecimento da aplicação de técnicas moleculares pode auxiliar em pesquisas relacionadas à epidemiologia e ao controle populacional dos vetores transmissores da esquistossomose mansônica.

Schistosomiasis is a parasitic disease that affects millions of people worldwide. This parasitosis is transmitted by snails that serve as intermediate hosts for digenetic helminths. The correct identification of the transmitting species can help in the epidemiological knowledge of the disease. However, conventional methods of classification may present questionable results due to intraspecific variation between specimens. As a result, this review aimed to describe the main molecular techniques that can be applied, as well as describe the improvement of the methods over time. PCR is a technique developed through the polymerization of DNA strands carried out in vitro, where it amplifies the DNA in multiple copies by enzymatic replication, without needing a living organism. In real-time PCR, amplification, detection and quantification phases are fully automated, occurring simultaneous. The evolution of the conventional technique resulted in the advent of Protein C Reactive - Restriction Fragment Length Polymorphism (PCR-RFLP), microsatellites, and Protein C Reactive ­ Random Amplification of Polymorphic DNA (PCR-RAPD). Through these variants it was possible to accurately classify the transmitting species, perform the analysis of intraspecific genetic variability and expand the phylogenetic studies of the populations. Knowledge of the application of molecular techniques can assist in research related to the epidemiology and population control of these vectors that transmit schistosomiasis mansoni.

Metapopulation dynamics of the migratory fish Prochilodus lineatus (Characiformes: Prochilodontidae) in a lotic remnant of the Grande River, Southeastern Brazil

River impoundments for electricity generation lead to environmental changes which severely affect fish migration and species richness. However, little is known about their effect on the genetic structure and population dynamics downstream from the reservoir. Here, we analyzed a set of ten microsatellite loci of Prochilodus lineatus, an important South American migratory fish. Specimens (n = 150) were sampled from five sites in a remnant lotic system that includes sections of the Grande, Pardo and Mogi Guaçu rivers, southeastern Brazil. The data showed that all microsatellites were polymorphic with the allele number per locus ranging from 5 to 32, and genetic diversity (H e ) varied from 0.74 to 0.80. Indices of genetic differentiation and Bayesian analysis showed a significant genetic structure and three genetic clusters inhabiting this river system. An asymmetric gene flow suggests source-sink metapopulation dynamics from tributaries (genetic source) to the main river (genetic sink). A genetic cluster that was not detected in the upper Mogi and Pardo rivers tributaries may indicate there is a "trapped gene pool" downstream from the Porto Colômbia dam. Thus, here we provide new insights into the genetic structure and population dynamics of a migratory fish species in a highly dammed river basin.(AU)

Represamento de rios para geração de eletricidade levam a mudanças ambientais que afetam severamente a migração de peixes e riqueza de espécies. No entanto, pouco se sabe sobre seu efeito na estrutura genética e dinâmica populacional a jusante de reservatórios. Aqui, analisamos um conjunto de dez loci de microssatélites de Prochilodus lineatus, um importante peixe migratório sul-americano. Os espécimes (n = 150) foram amostrados em cinco locais de um sistema lótico remanescente que inclui seções dos rios Grande, Pardo e Mogi Guaçu, sudeste do Brasil. Os dados mostraram que todos microssatélites eram polimórficos com o número de alelos por locus variando de 5 a 32 e diversidade genética (H e ) variou de 0,74 a 0,80. Índices de diferenciação genética e análise de agrupamento baseada em modelo bayesiano indicou a presença de três agrupamentos genéticos habitando este sistema fluvial. Um fluxo gênico assimétrico sugere dinâmica metapopulacional de fonte-sumidouro dos tributários (fonte genética) para o rio principal (sumidouro genético). Um agrupamento genético que não foi detectado nos tributários rio Mogi e rio Pardo parecem indicar que há um "trapped gene pool" a jusante da represa de Porto Colômbia. Assim, nós provemos aqui novos conhecimentos sobre a estrutura genética e dinâmica populacional de uma espécie de peixe migratório em um rio altamente fragmentado por barramentos.(AU)

Metapopulation dynamics of the migratory fish Prochilodus lineatus (Characiformes: Prochilodontidae) in a lotic remnant of the Grande River, Southeastern Brazil

River impoundments for electricity generation lead to environmental changes which severely affect fish migration and species richness. However, little is known about their effect on the genetic structure and population dynamics downstream from the reservoir. Here, we analyzed a set of ten microsatellite loci of Prochilodus lineatus, an important South American migratory fish. Specimens (n = 150) were sampled from five sites in a remnant lotic system that includes sections of the Grande, Pardo and Mogi Guaçu rivers, southeastern Brazil. The data showed that all microsatellites were polymorphic with the allele number per locus ranging from 5 to 32, and genetic diversity (H e ) varied from 0.74 to 0.80. Indices of genetic differentiation and Bayesian analysis showed a significant genetic structure and three genetic clusters inhabiting this river system. An asymmetric gene flow suggests source-sink metapopulation dynamics from tributaries (genetic source) to the main river (genetic sink). A genetic cluster that was not detected in the upper Mogi and Pardo rivers tributaries may indicate there is a "trapped gene pool" downstream from the Porto Colômbia dam. Thus, here we provide new insights into the genetic structure and population dynamics of a migratory fish species in a highly dammed river basin.(AU)

Represamento de rios para geração de eletricidade levam a mudanças ambientais que afetam severamente a migração de peixes e riqueza de espécies. No entanto, pouco se sabe sobre seu efeito na estrutura genética e dinâmica populacional a jusante de reservatórios. Aqui, analisamos um conjunto de dez loci de microssatélites de Prochilodus lineatus, um importante peixe migratório sul-americano. Os espécimes (n = 150) foram amostrados em cinco locais de um sistema lótico remanescente que inclui seções dos rios Grande, Pardo e Mogi Guaçu, sudeste do Brasil. Os dados mostraram que todos microssatélites eram polimórficos com o número de alelos por locus variando de 5 a 32 e diversidade genética (H e ) variou de 0,74 a 0,80. Índices de diferenciação genética e análise de agrupamento baseada em modelo bayesiano indicou a presença de três agrupamentos genéticos habitando este sistema fluvial. Um fluxo gênico assimétrico sugere dinâmica metapopulacional de fonte-sumidouro dos tributários (fonte genética) para o rio principal (sumidouro genético). Um agrupamento genético que não foi detectado nos tributários rio Mogi e rio Pardo parecem indicar que há um "trapped gene pool" a jusante da represa de Porto Colômbia. Assim, nós provemos aqui novos conhecimentos sobre a estrutura genética e dinâmica populacional de uma espécie de peixe migratório em um rio altamente fragmentado por barramentos.(AU)

Population genetics of the endangered catfish Pseudoplatystoma magdaleniatum (Siluriformes: Pimelodidae) based on species-specific microsatellite loci

The Neotropical catfish genus Pseudoplatystoma comprises eight species of large size, widely distributed in South American basins. The endangered species P. magdaleniatum is endemic to Magdalena basin (Colombia), experiences high fishing pressure and its population genetics is relatively unknown. To study the genetic status and structure of P. magdaleniatum, 25 species-specific polymorphic microsatellite loci were developed using next-generation sequencing and then tested in samples collected in the Magdalena-Cauca basin. Based on 15 of these loci, P. magdaleniatum showed a high number of alleles per locus (9-10), high values of observed (0.762-0.798) and expected (0.770-0.791) heterozygosities, recent reduction of population size and gene flow. These findings constitute a baseline to measure potential changes in genetic diversity and structure of this commercially important species in a basin undergoing high anthropogenic activities.(AU)

El género de bagres neotropicales Pseudoplatystoma comprende ocho especies de gran tamaño, ampliamente distribuidas en las cuencas de Suramérica. La especie en peligro de extinción P. magdaleniatum es endémica de la Cuenca del Magdalena (Colombia), experimenta una alta presión pesquera y su genética poblacional es relativamente desconocida. Para estudiar el estado y estructura genética de P. magdaleniatum, se desarrollaron 25 loci microsatélites polimórficos especie específicos utilizando secuenciación de próxima generación y se evaluaron en muestras recolectadas en la Cuenca del Magdalena-Cauca. Con base en 15 loci, P. magdaleniatum mostró un alto número de alelos por locus (9-10), valores altos de heterocigosidad observada (0.762-0.798) y esperada (0.770-0.791), reducción reciente del tamaño poblacional y flujo génico. Estos hallazgos constituyen una línea de base para medir cambios potenciales en la diversidad y estructura genética de esta especie comercialmente importante en una cuenca sometida a altas actividades antropogénicas.(AU)