Genetic diversity of Saccharum complex using ISSR markers.

Sugarcane (Saccharum sp, Poaceae) is native to Southeast Asia, and due to growing demand as raw material, its cultivation recently expanded to new frontiers. The genetic diversity analysis is essential for targeting strategies in the formation and maintenance of a germplasm. This study aimed to assess the genetic diversity of 26 accessions of sugarcane from the Active Germplasm Bank of Embrapa Coastal Tablelands, using inter-simple sequence repeat (ISSR) molecular markers. Sixteen primers were used, resulting in 87 fragments with 91.13% of polymorphism. The similarity of the individuals ranged between 0.22 and 0.87. Individuals RB867515 and RB92579 were closer genetically, and the most distant ones were PI240785 and NSL 291970. Four distinct clusters were formed, using UPGMA. This information can be used to prioritize the selection of accessions for the conduction of hybridization in breeding and germplasm exchange actions.

Diversity and genetic stability in banana genotypes in a breeding program using inter simple sequence repeats (ISSR) markers.

Banana (Musa spp) is a fruit species frequently cultivated and consumed worldwide. Molecular markers are important for estimating genetic diversity in germplasm and between genotypes in breeding programs. The objective of this study was to analyze the genetic diversity of 21 banana genotypes (FHIA 23, PA42-44, Maçã, Pacovan Ken, Bucaneiro, YB42-47, Grand Naine, Tropical, FHIA 18, PA94-01, YB42-17, Enxerto, Japira, Pacovã, Prata-Anã, Maravilha, PV79-34, Caipira, Princesa, Garantida, and Thap Maeo), by using inter-simple sequence repeat (ISSR) markers. Material was generated from the banana breeding program of Embrapa Cassava & Fruits and evaluated at Embrapa Coastal Tablelands. The 12 primers used in this study generated 97.5% polymorphism. Four clusters were identified among the different genotypes studied, and the sum of the first two principal components was 48.91%. From the Unweighted Pair Group Method using Arithmetic averages (UPGMA) dendrogram, it was possible to identify two main clusters and subclusters. Two genotypes (Garantida and Thap Maeo) remained isolated from the others, both in the UPGMA clustering and in the principal cordinate analysis (PCoA). Using ISSR markers, we could analyze the genetic diversity of the studied material and state that these markers were efficient at detecting sufficient polymorphism to estimate the genetic variability in banana genotypes.

Genetic diversity in natural populations of mangaba in Sergipe, the largest producer State in Brazil.

Mangaba (Hancornia speciosa Gomes) is found in areas of coastal tablelands in the Brazilian Northeast and Cerrado regions. This species has been subjected to habitat fragmentation that is mainly due to human activity, and requires conservation strategies. The aim of this study was to analyze the structure and inter- and intrapopulation genetic diversity of natural populations of H. speciosa Gomes using inter-simple sequence repeat (ISSR) molecular markers. A total of 155 individuals were sampled in 10 natural populations (ITA, PAC, IND, EST, BC, PIR, JAP, BG, NEO, and SANT) in the State of Sergipe, Brazil. Fifteen primers were used to generate 162 fragments with 100% polymorphism. Genetic analysis showed that the variability between populations (77%) was higher than within populations (23%). It was possible to identify five different groups by the unweighted pair group method with arithmetic mean and principal coordinate analysis, and only one individual (E10) remained isolated. Using ISSR markers it was possible to obtain a molecular profile of the populations evaluated, showing that these markers were effective and exhibited sufficient polymorphism to estimate the genetic variability of natural populations of H. speciosa Gomes.

Diversity and genetic structure of mangaba remnants in states of northeastern Brazil.

In this study, we analyzed the genetic diversity and structure of remnants of mangaba populations in states of northeastern Brazil by applying 9 microsatellite markers previously developed to establish conservation strategies for germplasm and species preservation. Six to 20 individuals per population were analyzed, with a total of 94 individuals and 6 populations from the states of Ceará, Pernambuco, and Sergipe, Brazil. The intra-population positive fixation index (f) in all populations indicated inbreeding resulting from the lack of random mating. The mean genetic diversity index values GST, FST, and RST estimated for divergence among the 6 populations were 0.14 (P < 0.05), revealing moderate genetic differentiation. The smallest FST value (P ≥ 0.05) was observed between the Jacarecoara and Tapera populations (0.005) and the highest between the Barra dos Coqueiros and Jacarecoara populations (0.287). The Jacarecoara population was the most divergent among the populations analyzed. According to analysis of molecular variance results, the largest variation percentage resulted from variability within populations (83.18%). Bayesian clustering analysis showed the formation of 2 sets (K = 2). Our results are important for developing strategies for in situ conservation of the species, seed collection, and ex situ conservation. For both methods, conservation of the greatest possible genetic variability of the species is essential.

New insights into opioid regulatory pathways: influence of opioids on Wnt1 expression in zebrafish embryos.

Opioids are the most potent analgesics known today, but their prolonged administration produces severe adverse effects such as constipation, bradycardia, besides addiction, a concept not fully understood at present, which represents one of the most important challenges of modern bioscience. Wnts constitute an important family of vertebrate genes that encode secreted signaling proteins implicated in various developmental processes (patterning of the neural tube, neuronal differentiation), and are extensively conserved through evolution. In this study we have focused on Wnt1, an essential signal in axis polarity, as well as in proliferation and the development and differentiation of the CNS, roles shared by opioid receptors. Our previous studies in zebrafish show that morphine, the most potent analgesic known today, increases cell proliferation and induces neuronal protection and dopaminergic differentiation by activating the opioid receptors. The aim of the present study is to determine whether these effects are a consequence of an interaction between Wnt1 and the endogenous opioid system, which may act as a transcription regulator of Wnt1. Hence, we have exposed embryos to morphine, the endogenous delta opioid agonist Met-Enkephalin-Glu-Tyr (MEGY) (it binds with high affinity to both zebrafish delta opioid receptors, ZfDORs), and SNC80, a highly specific delta agonist, which displays low affinity towards the ZfDORs. Although at earlier stages, all opioids reduced the expression level of Wnt1, further on development, mainly during the differentiation of the CNS (24-48 h post fertilization (hpf)), morphine and MEGY increased Wnt1 expression. Our results point to the possibility that opioid signaling controls the transcription of Wnt1 and that through Wnt1, the opioid system regulates cell proliferation and neuronal differentiation. The present work opens a door to the discovery of new mechanisms that regulate opioid activity and its adverse effects, and hence, it might provide a good target to design new drugs that prevent or avoid these effects.