Genetic characterization of 12 heterologous microsatellite markers for the giant tropical tree Cariniana legalis (Lecythidaceae)

Twelve microsatellite loci previously developed in the tropical tree Cariniana estrellensis were genetically characterized in Cariniana legalis. Polymorphisms were assessed in 28 C. legalis individuals found between the Pardo and Mogi-Guaçu River basins in the state of São Paulo, Brazil. Of the 12 loci, 10 were polymorphic and exhibited Mendelian inheritance. The allelic richness at each locus ranged from 2-11, with an average of 7 alleles per locus, and the expected heterozygosity ranged from 0.07-0.88. These loci showed a high probability of paternity exclusion. The characteristics of these heterologous microsatellite markers indicate that they are suitable tools for investigating questions concerning population genetics in C. legalis

Genetic characterization of 12 heterologous microsatellite markers for the giant tropical tree Cariniana legalis (Lecythidaceae)

Twelve microsatellite loci previously developed in the tropical tree Cariniana estrellensis were genetically characterized in Cariniana legalis. Polymorphisms were assessed in 28 C. legalis individuals found between the Pardo and Mogi-Guaçu River basins in the state of São Paulo, Brazil. Of the 12 loci, 10 were polymorphic and exhibited Mendelian inheritance. The allelic richness at each locus ranged from 2-11, with an average of 7 alleles per locus, and the expected heterozygosity ranged from 0.07-0.88. These loci showed a high probability of paternity exclusion. The characteristics of these heterologous microsatellite markers indicate that they are suitable tools for investigating questions concerning population genetics in C. legalis

Genetic Studies Of Forest Species Cariniana estrellensis (Raddi) Kuntez: Diversity, Mating System and Contemporary Gene Flow.

Cariniana estrellensis (Raddi) Kuntez (Lecythidaceae), popularmente conhecida como jequitibá branco, é uma espécie arbórea climácica neotropical cuja sobrevivência encontra-se ameaçada devido aos processos de degradação de seus ambientes naturais e exploração indevida. Visando contribuir para a conservação in situ e ex situ deste recurso genético, o objetivo deste trabalho foi investigar a diversidade genética, o sistema de reprodução, a estrutura genética espacial e o fluxo gênico contemporâneo de C. estrellensis em um pequeno remanescente florestal (8 ha) localizado na Região de Ribeirão Preto SP (município de Cravinhos), usando como ferramenta de análise um conjunto de nove marcadores microssatélites (SSR) desenvolvidos para a espécie. Todas as árvores adultas reprodutivas (30) e regenerantes (39) existentes no referido fragmento foram mapeadas e tiveram tecidos foliares amostrados para as análises genéticas. Sementes de polinização natural foram também aleatoriamente coletadas em algumas destas árvores adultas durante dois eventos reprodutivos, obtendo-se um total de 644 progênies. Através das análises SSR constatou-se que todas as gerações de C. estrellensis apresentaram altos níveis de diversidade genética e ausência de endogamia, evidenciando a alogamia da espécie. Em concordância, as taxas de cruzamentos (tm) estimadas para os dois eventos reprodutivos não diferiram estatisticamente da unidade, permitindo afirmar que C. estrellensis é uma espécie perfeitamente alógama, com indícios de mecanismos de auto-incompatibilidade. Estimativas da correlação de paternidade (rp(m) (evento 1) = 0,121 e rp(m) (evento 2) = 0,145) e do coeficiente de coancestralidade médio dentro de progênies (xy (evento 1) = 0,140 e xy (evento 2) = 0,141) indicaram a ocorrência de pequenos desvios de cruzamentos aleatórios na população de C. estrellensis. O número efetivo de doadores de pólen estimado foi mais alto entre frutos de uma mesma árvore (10,20(evento 1); 10,31(evento 2) ) do que dentro de um mesmo fruto (1,33(evento 1); 1,17(evento 2)). Os resultados também revelaram que não existe estruturação genética espacial na população de C. estrellensis. As análises de parentesco em C. estrellensis revelaram distâncias médias curtas do fluxo de pólen dentro do fragmento tanto para as progênies (69,95±60 m(evento 1); 112,02±94 m (evento 2)) quanto para os regenerantes (146,94±98 m). Além disso, os resultados das análises de parentesco nos regenerantes apontaram ausência de imigração de sementes na população e indicaram que a taxa de imigração de pólen realizado (variando entre 53 % e 62 %) foi maior que as taxas de imigração de pólen efetivo (variando entre 23,5 % e 37 %) para os dois eventos reprodutivos estudados. Os altos níveis de imigração de pólen detectados no fragmento em estudo sugeriram que a população de C. estrellensis não está isolada reprodutivamente, o que pode ser essencial para prevenir perdas de diversidade genética da espécie, garantindo sua sobrevivência em longo prazo. Em termos gerais, a população estudada mostrou resiliência aos efeitos adversos da fragmentação e potencial para fins de conservação in situ e ex situ.Cariniana estrellensis (Raddi) Kuntze (Lecythidaceae), commonly known as jequitibá branco, is a large neotropical tree, characteristic of the climax forest whose survival is threatened due to processes of degradation of natural environments and improper exploitation. In this study, it was investigated the temporal patterns of genetic variability, reproductive systems, spatial genetic structure and contemporary gene flow in the remaining population of the tropical forest species C. estrellensis that occurs naturally in a small fragment (8 ha) located in the Ribeirão Preto region-SP (municipality of Cravinhos), using nine pairs of microsatellite loci. All adult trees (30) and saplings (39) found in the fragment were mapped and sampled. Naturally-pollinated seeds were randomly collected from seed-trees that were reproductive for two consecutive years resulting in a total of 644 offspring. Through the analysis with SSR, all generations of C. estrellensis (adults, saplings and offspring) showed high levels of genetic diversity and no inbreeding. Estimates of multi-locus outcrossing rates (tm) suggested that C. estrellensis is a perfectly allogamus species, with evidence of selfincompatibility. Estimates of the correlation of paternity (rp(m) (event 1) = 0.121 and rp(m) (event 2) = 0.145) and the average of the coefficient of coancestry within progenies (xy (event 1) = 0.140 and xy (event 2) = 0.141) indicated a small deviation from random mating. The effective number of pollen donors was higher among fruits from the same tree (10.20(event 1), 10.31(event 2)) than within the same fruit (1.33(event 1), 1.17(event 2)). The results also revealed a lack of spatial genetic structure in C. estrellensis population. Parentage analyses revealed short average distances of pollen flow within the fragment for both offspring generations (69.95 ± 60 m (event 1); 112.02 ± 94 m (event 2)) as well as for saplings (146.94 ± 98 m). Furthermore, the parentage analyses in the saplings pointed no seed immigration in the population studied and indicated that the realized pollen immigration (ranging between 53 % and 62 %) was higher than the rates of effective pollen immigration (ranging between 23.5 % and 37 %) for both reproductive events studied. High levels of pollen immigration from outside study site suggested that the population of C. estrellensis is not reproductively isolated, which may be essential to prevent losses of genetic diversity in the species, ensuring its long-term survival. Overall, the studied population shows resilience to adverse effects of fragmentation and potential for in situ and ex situ conservation

Depicting the mating system and patterns of contemporary pollen flow in trees of the genus Anadenanthera (Fabaceae)

Anadenanthera (Fabaceae) is endemic to the Neotropics and consists of two tree species: A. colubrina (Vell.) Brenan and A. peregrina (L.) Speg. This study examined the mating system and contemporary gene flow of A. colubrina (Acol) and A. peregrina (Aper) in a highly fragmented area of the Atlantic Forest to provide valuable information that informs conservation strategies. Reproductive adults from forest remnants [nA. colubrina = 30 (2.7 ha), nA. peregrina = 55 (4.0 ha)] and progeny-arrays (nA. colubrina = 322, nA. peregrina = 300) were genotyped for seven nuclear microsatellite markers. Mating system analyses revealed that A. colubrina is a mixed mating species (tm = 0.619) while A. peregrina is a predominantly outcrossing species (tm = 0.905). For both Anadenanthera species, high indices of biparental inbreeding were observed (Acol = 0.159, Aper = 0.216), resulting in low effective pollination neighborhood sizes. Categorical paternity analysis revealed different scales of pollen dispersal distance: the majority of crossings occurring locally (i.e., between nearby trees within the same population), with moderate pollen dispersal coming from outside the forest fragments boundaries (Acolmp = 30%, Apermp = 35%). Nevertheless, pollen immigration from trees outside the populations for both species suggests that the populations are not reproductively isolated. This study highlights the importance of evaluating both mating system and contemporary gene flow for a better understanding of the biology of Anadenanthera species. This information should be considered to ensure the effective conservation and management practices of these plant species

Microsatellite diversity and effective population size in a germplasm bank of Hymenaea courbaril var. stilbocarpa (Leguminosae), an endangered tropical tree: recommendations for conservation

Deforestation in southeast Brazil has led to the extinction of Hymenaea courbaril var. stilbocarpa and ex situ conservation has been established. In this study, the levels of genetic diversity and the effective population size of H. courbaril in a germplasm bank were investigated using six nuclear microsatellite loci. A total of 79 and 91 alleles were found in 65 seed-trees and their 176 offspring, respectively. Offspring have a higher average number of alleles per locus (A = 15.2) than seed-trees (A = 13.2), but lower observed heterozygosity (offspring: H (o) = 0.566; seed-trees: H (o) = 0.607). The estimate of outcrossing rate shows that the study population is perfectly outcrossed (t (m) = 0.978, P > 0.05). Significant deviations from random mating were detected through mating among relatives and correlated matings. The average variance in effective population size for each family was 2.63, with a total effective population size retained in the bank of 170.1. These results confirm that the preserved population of H. courbaril retains substantial genetic variability.FAPESP[03/04199-4]Sao Paulo University (USP)FAEPACAPE