Development and characterization of microsatellite markers in Stryphnodendron adstringens (Leguminosae).

In this study, we report the development and characterization of 15 new microsatellite markers for Stryphnodendron adstringens (Leguminosae) in order to support future analyses of genetic diversity in populations of this species. In screening with 48 individuals from three different populations of S. adstringens, we tested the amplification of 20 microsatellite loci, of which five are not useful for population genetic studies due to the lack of polymorphisms or amplification failures. For the final set of 15 loci, the number of alleles ranged from 2 to 15, with a total of 116 alleles. The expected heterozygosity ranged from 0.1219 to 0.8965, with an average of 0.6694 per locus. The combined probability of genetic identity (PI = 8.12 × 10-15) and paternity exclusion (Q = 0.99999) estimations showed that the loci may be useful to discriminate between individuals of S. adstringens. Initial cross-amplification tests were satisfactory in three species of the genus Stryphnodendron: S. rotundifolium, S. coriaceum and S. polyphyllum. This new set of markers will be a useful tool for population genetic studies, contributing to the knowledge about the evolutionary history of S. adstringens and, additionally, correlated species.

The complete chloroplast genome of Stryphnodendron adstringens (Leguminosae - Caesalpinioideae): comparative analysis with related Mimosoid species.

Stryphnodendron adstringens is a medicinal plant belonging to the Leguminosae family, and it is commonly found in the southeastern savannas, endemic to the Cerrado biome. The goal of this study was to assemble and annotate the chloroplast genome of S. adstringens and to compare it with previously known genomes of the mimosoid clade within Leguminosae. The chloroplast genome was reconstructed using de novo and referenced-based assembly of paired-end reads generated by shotgun sequencing of total genomic DNA. The size of the S. adstringens chloroplast genome was 162,169 bp. This genome included a large single-copy (LSC) region of 91,045 bp, a small single-copy (SSC) region of 19,014 bp and a pair of inverted repeats (IRa and IRb) of 26,055 bp each. The S. adstringens chloroplast genome contains a total of 111 functional genes, including 77 protein-coding genes, 30 transfer RNA genes, and 4 ribosomal RNA genes. A total of 137 SSRs and 42 repeat structures were identified in S. adstringens chloroplast genome, with the highest proportion in the LSC region. A comparison of the S. adstringens chloroplast genome with those from other mimosoid species indicated that gene content and synteny are highly conserved in the clade. The phylogenetic reconstruction using 73 conserved coding-protein genes from 19 Leguminosae species was supported to be paraphyletic. Furthermore, the noncoding and coding regions with high nucleotide diversity may supply valuable markers for molecular evolutionary and phylogenetic studies at different taxonomic levels in this group.

Genetic and chemical diversity of Uncaria tomentosa (Willd. ex. Schult.) DC. in the Brazilian Amazon.

Uncaria tomentosa (Willd. ex Schult.) DC., a plant native to the Amazon region, is used widely in popular medicine and by the pharmaceutical industry because of its anti-inflammatory activity. However, the survival of this species is endangered by deforestation and indiscriminate collection, and a preservation plan is urgently required. The objectives of this study were to determine the genetic and chemical variability between and within eight populations of U. tomentosa from the Brazilian states of Acre, Pará and Amapá, and to investigate possible correlations between genetic and geographical distances, and between geographical distances or altitude and the accumulation of bioactive oxindole alkaloids. Three sequence-related amplified polymorphism (SRAP) markers were employed to fingerprint genomic DNA, and the amounts of mitraphylline and isomitraphylline in leaf samples were established by high-performance liquid chromatography. Although significant divergence existed between the tested populations (FST = 0.246), the largest genetic diversity and the highest percentage of polymorphism (95.68%) was found within the population from Mâncio Lima, Acre. Gene flow was considered rather limited (Nm = 1.57), and no correlations between genetic and geographical distances were detected, suggesting that population structure followed an island model. Accumulations of mitraphylline and isomitraphylline varied in the range 32.94 to 0.57 and 3.75 to 0.36 mg g-1 dry weight, respectively. The concentration of isomitraphylline was positively influenced by altitude, such that the population collected at the site with the highest elevation (Tarauacá, Acre) exhibited the greatest alkaloid content. SRAP markers were very efficient in fingerprinting genomic DNA from U. tomentosa populations and clearly showed that genetic variability within populations was greater than between populations. A conservation and management plan should prioritize the creation of germplasm banks to prevent the loss of existing genetic variability, particularly within alkaloid-rich populations such as those of Tarauacá.