Development and characterization of microsatellite loci for Campomanesia xanthocarpa (Myrtaceae) and cross amplification in related species

Campomanesia xanthocarpa is a native tree, of common occurrence in almost all Brazilian Forest formations, which has its fruits and timber with high commercial value. Using an enriched genomic library we isolated and characterized microsatellite loci for C. xanthocarpa (Myrtaceae), in order to estimate genetic diversity parameters for this and related species. Twenty-eight microsatellite loci were identified and ten of them successfully amplified and showed polymorphism in a sample of 96 individuals, from four natural populations. The number of alleles per locus ranged from two to eight, and the observed and expected heterozygosities varied from 0.042 to 1.000 and from 0.294 to 0.855, respectively. These markers were tested and validated in two related species (C. eugenioides and C. guazumifolia). The microsatellite markers will be used in further studies of population genetics of C. xanthocarpa, in order to understand the genetic variability and to define the strategies needed for the conservation of the species.

O alagamento do solo afeta a sobrevivência, o crescimento e o metabolismo de Aegiphila sellowiana Cham. (Lamiaceae) / Soil flooding affects the survival, growth and metabolism of Aegiphila sellowiana Cham. (Lamiaceae)

Visando a elucidar aspectos da tolerância à hipoxia, plantas de Aegiphila sellowiana Cham. (Lamiaceae) foram submetidas a diferentes períodos de inundação. A sobrevivência, o crescimento, a condutância estomática e a fotossíntese foram avaliados. Houve mortalidade de 33,3% das plantas alagadas. Dentre as 66,7% sobreviventes, a taxa de crescimento relativo (TCR) de raízes, caule, folhas e da planta inteira foi inferior à TCR das plantas cultivadas em solo drenado. As plantas alagadas apresentaram produção de raízes diageotrópicas, maior abscisão foliar e baixa produção de novas folhas. O alagamento provocou redução na condutância estomática e na taxa fotossintética. Sugere-se que A. sellowiana possui intolerância ao alagamento do solo.

In order to elucidate aspects of tolerance to hypoxia, Aegiphila sellowiana Cham. (Lamiaceae) plants were submitted to different periods of flooding. The survival, growth, stomatal conductance and photosynthesis were evaluated. There was 33,3% of mortality of flooded plants. Among the 66,7% of survivors, the relative growth rate (RGR) of roots, stems, leaves and whole plant was lower than the RGR of plants cultivated in drained soil. Flooded plants presented diageotrophic root production, increased leaf abscission and low production of new leaves. Flooding caused a reduction in stomatal conductance and photosynthetic rate. It is suggested that A. sellowiana has intolerance to soil flooding.

Genetic variability of three natural populations of Maytenus aquifolium (Celesteraceae) from Telêmaco Borba, Paraná, Brazil

Three populations of Maytenus aquifolium from Monte Alegre farm, Telemaco Borba county, Paraná, Brazil were analyzed by RAPD markers. A total of 13 primers were applied wich yielded 283 well amplified markers in all the studied populations (Mortandade, Vila Preta and Trinita), producing different values of gene diversity and polymorphic loci. The analysis of molecular variance (AMOVA) indicated that 21.77 percent of the genetic variation was among the population. Pairwise F ST analysis showed that the most divergent populations were closer geographically, demonstrating that other factors such as different soil types could explain this variation. Bayesian analysis for K number of clusters and the Principal Coordinate indicated that these three populations were highly structured, corroborating the high values found for the F ST and indicating that for conservation purposes all populations should be maintained.

Três populações de Maytenus aquifolium coletadas na fazenda Monte Alegre, localizada no município de Telêmaco Borba, Paraná, Brasil foram analisadas por marcadores de RAPD. Treze primers de RAPD foram amplificados produzindo 283 bandas com alta capacidade de repetição nas três populações estudadas (Mortandade, Trinita e Vila Preta), com as quais valores diferentes de diversidade gênica e locos poplimórficos foram calculados. Análise da variância molecular (AMOVA) mostrou que 21,77 por cento da variabilidade genética é encontrada entre populações. Análise do Fst entre pares de populações mostrou que as mais divergentes são geograficamente mais próximas, demonstrando que outros fatores tais como tipos distintos de solos podem explicar estas variações. Análise Bayesiana para número K de clusters e a Análise da Coordenada Principal mostraram que estas três populações estão altamente estruturadas, corroborando os altos valores encontrados para o Fst e indicando que para propósitos de conservação todas as populações devem ser mantidas.

Genetic diversity among forty coffee varieties assessed by RAPD markers associated with restriction digestion

A variabilidade genética de 40 acessos de cafeeiros de fenótipo arabica foi obtida usando a técnica de RAPD associada a uma digestão prévia do DNA genômico com endonucleases. A variabilidade genética e a relação entre os accessos foram inicialmente avaliadas pela amplificação de 195 primers. Para incrementar a eficiência na detecção de polimorfismo, o DNA genômico de cada acessos foi submetido a digestão com endonucleases antes da PCR. Um total de 24 primers combinados com restrição do DNA gerou 318 bandas, das quais 266 (83,65%) foram polimórficas. A associação entre os 40 acessos foi estimada pelo método de clusters UPGMA, sendo os acessos agrupados de acordo com seu pedigree e aspectos agronômicos. Os resultados mostraram que o uso de enzimas de restrição antes da reação de amplificação pode ser considerada uma ferramenta eficiente para incrementar o número de bandas informativas, possibilitando a diferenciação entre os 40 acessos de C. arabica.

Genetic polymorphism among 14 elite Coffea arabica L. cultivars using RAPD markers associated with restriction digestion

Knowledge of the genetic variability among genotypes is important for the transfer of useful genes and to maximize the use of available germplasm resources. This study was carried out to assess the genetic variability of 14 elite Coffea arabica cultivars using random amplified polymorphic DNA (RAPD) associated with a prior digestion of genomic DNA with restriction endonucleases. The accessions were obtained from the Coffea collection maintained at the Instituto Agronomico do Parana (IAPAR), located in Londrina, Parana, Brazil. Twenty-four informative RAPD primers, used in association with restriction enzymes, yielded 330 reproducible and scorable DNA bands, of which 224 (68 per cent) were polymorphic. The amplified products were used to estimate the genetic variability using Dice's similarity coefficient. The data matrix was converted to a dendrogram and a three-dimensional plot using principal coordinate analysis. The accessions studied were separated into clusters in a manner that was consistent with the known pedigree. The associations obtained in the dendrogram and in the principal coordinate analysis plot suggest the probable origin of the Kattimor cultivar. The RAPD technique associated with restriction digestion was proved to be a useful tool for genetic characterization of C. arabica genotypes making an important contribution to the application of molecular markers to coffee breeding