Table of contents: 2019
In order to facilitate corn production, herbicides such as nicosulfuron and topramezone are commonly used. Though they offer great advantages, they can affect crop productivity and induce DNA damage. The genotoxic activity of nicosulfuron was evaluated at two concentrations (40,000 and 80,000 ppm) and topramezone at four concentrations (1480, 148, 14.8 and 1.48 ppm) respectively, in sweet corn and hybrid accessions from Mexico and South America using a comet assay system. Sweet corn apical meristematic cell nuclei were tested in 113 accessions from Mexico and South America and five commercial hybrids for nicosulfuron and nine accessions and a hybrid for topramezone. Both nicosulfuron concentrations induced significant genetic damage to sweet corn and normal hybrids. Topramezone showed significant genotoxic activity in both sweet corn and normal hybrids. Normal hybrid corn was subject to genetic damage caused by the herbicides, and all showed significant genetic damage compared to their corresponding untreated controls. Genotoxic activity of nicosulfuron and topramezone was evident; additionally, the comet assay study demonstrated that corn can be used as a biomonitor for genotoxicity assessment.
Genetic diversity is the basis for genetic improvement as it can provide the basis for new cultivars. Stylosanthes scabra is a grasslands legume that presents potential economic importance in tropical and subtropical regions. Plants of the genus Stylosanthes naturally occur in semiarid native pastures in northeastern Brazil and are highly favored by grazing animals; therefore Brazil's Northeast stands out as an center of this genus. We evaluated the genetic diversity of S. scabra using ISSR molecular markers; naturally occurring samples were harvested from Santa Cruz do Capibaribe, Floresta, Sertânia and Petrolina in Pernambuco state, Brazil. We selected seven ISSR primers for amplification and analyzed 75 individuals, obtaining 88 bands, which amplified with 95% polymorphism at the species level. The AMOVA test revealed that 40% of the total genetic variation occurs within populations and 60% among populations. Population differentiation was 0.332 and the migrant number per generation was 0.5. Grouping analysis confirmed a high level of differentiation among populations and that the greatest variability was in Santa Cruz do Capibaribe and Petrolina regions. The ISSR markers were efficient for genetic diversity quantification in S. scabra, which presented greater variability among populations than within them. Overall, the population variability found will be useful for breeding programs for this species.
Coffea canephora shows considerable variability for several agronomic traits, including nutritional efficiency. Beside the intrinsic nutritional efficiency of a genotype, the availability of water in the soil is another factor that can cause different responses, which suggests the possibility of selection of genotypes to enhance the nutritional efficiency under different scenarios, such as plantings in areas with low natural fertility or subjected to drought. We evaluated the genetic diversity of genotypes of C. canephora that compose the cultivar “BRS Ouro Preto”, the first available clonal cultivar recommended for Rondonia State, based on parameters of nutritional status of the plants subjected to cultivation under conditions of abundant water supply or subjected to water deficit. To this end, the experiment was developed with two trials where the 15 genotypes of this cultivar were cultivated in a greenhouse, under conditions of abundant water supply or subjected to water deficit. The trials followed a completely randomized design, with four replications and the mineral status of the plants was evaluated based on the content of N, P, K, Ca, Mg and S of their green tissues. The genotypes presented high variability for these nutritional parameters, making it possible to identify distinct patterns and to group them according to their nutritional status. Variability was affected by drought, showing that the water supply can cause changes in patterns of nutritional status and affect the clustering of genotypes. The genotypic effect surpassed the environmental influence for most mineral parameters, resulting in a desirable scenario for a possible selection to enhance nutritional efficiency, for both irrigated and rainfed systems, within the group of genotypes that already present high yield in Rondonia state.
The development of common bean cultivars with biofortified grains for macrominerals and a seed coat color pattern that satisfies consumer preference is a new demand of breeding programs. However, combined selection for seed coat color and macromineral concentrations in common beans is unprecedented. The objectives of this work were to obtain estimates of genetic parameters for seed coat color and macromineral concentrations in a recombinant inbred line population of Mesoamerican common beans and to select superior common bean lines for a biofortification program. A biparental cross BRS Esteio × SCS 205 Riqueza resulted in 100 Mesoamerican common bean lines that were evaluated in the F5:6 and F5:7 generations. Seed coat color was evaluated in a colorimeter by values L* (white to black), a* (green to red), and b* (blue to yellow). Macromineral concentrations (potassium, calcium, and magnesium) were quantified by nitric‐perchloric acid digestion. A significant treatment effect for all traits evaluated at the F5:6 and F5:7 generations was observed. Seed coat color (L*, a*, and b* values) presented high heritability estimates (h2: 95.99 to 99.72%) and qualitative inheritance. Heritability estimates from intermediate to high magnitude (h2: 34.08 to 99.50%) were obtained for the concentrations of potassium, calcium, and magnesium. Transgressive segregation and quantitative inheritance for the macromineral concentrations were observed in the F5:7 generation. The four superior common bean lines selected by the index were L 83-17, L 69-17, BRS MG Pioneiro, and L 24-17. The lines L 83-17 and L 69-17 of black beans have darker grains (lower L*, a*, and b* values) and high concentrations of potassium, calcium, and magnesium. The lines BRS MG Pioneiro and L 24-17 of carioca beans present lighter grains (L* ≥ 55, a* ≤ 7 and b* ≤ 16), and high mineral concentration. These lines will be selected for a common bean biofortification program.
Cancer is a public health problem of increasing concern worldwide due to the growing increase in mortality rates. The identification of natural compounds with cytotoxic activity is important due to the ready availability and their ability to act effectively in reducing the incidence of cancer, without adverse side effects. Whole grape juice (Vitis labrusca) is often consumed by the population, which is an example of a product with a high content of bioactive compounds, such as flavonoids and resveratrol. To help determine the suitability of this natural product as a health aid, we evaluated the cytotoxic activity of organic and conventional whole grape juices, exposed or not to UV-C irradiation, on human liver tumor cells (HepG2/C3A) and on non-tumor lung cells (MRC-5), by the MTT assay (a colorimetric assay for assessing cell metabolic activity), for 24 and 48 h. All of the juices, at the highest concentrations (50-100 µL/mL), showed significant cytotoxic activity on HepG2/C3A cells, reducing cell proliferation from 78 to 47%, in relation to the control, especially, after 48 h of treatment. Both conventional grape juices had cytotoxic effects on MRC-5 cells at 24 h of treatment, but cell proliferation was reestablished after 48 h. Furthermore, organic grape juice stimulated the proliferation of this cell line, especially that produced from grape exposed to UV-C, possibly in consequence of the increased amount of antioxidants, such as anthocyanins, resveratrol and flavonoids in the fruits, which probably stimulated cell metabolism. This data supports the use of whole grape juice, due to it’s nutraceutical potential, mainly because of antioxidant activity, in particular organic juice, and our findings demonstrate the benefit of food production techniques that add nutritional value, such as post-harvest exposure to UV-C.
The efficiency of a selection index generally depends on the quality of the variance matrixes, which demands controlled experiments. Using Artificial Neural Networks (ANNs) trained from a selection index is advantageous for selecting genotypes since an ANN has the capacity to classify genotypes in an automated way. We propose the use of ANNs for the selection of alfalfa genotypes, based on a selection index. Data were collected from 77 alfalfa genotypes evaluated based on nine traits from four cuttings. The traits were divided into forage yield and nutritive value groups. In order for the ANNs to learn the classification pattern, the Tai index was used, which allows secondary traits to be included in the index to improve the gains of the main traits. An index was established for each group of traits, and based on the index scores the genotypes were subdivided into four classes (optimal, good, medium, and bad). After testing different topologies, ANNs were established for each index, according to the apparent error rates. The chosen ANNs were efficient in classifying the genotypes since the highest apparent error rate reached 15%, meaning that the ANNs efficiently captured the data pattern. Considering the ANN classification for both groups of traits, there was a high degree of agreement with the classification obtained from the Tai index, as expected. Even in the cuttings where the ANNs presented the worst performance, their potential to classify alfalfa genotypes was clear, because the wrong classifications were placed in groups close to the correct ones. This ensured that the best genotypes did not run the risk of being discarded, since they would not be classified in the group of bad genotypes. The ANNs that were developed have good potential for use in alfalfa breeding programs.
Endometriosis is a chronic disease with adverse implications for fertility. We investigated the G894T polymorphism in the endothelial nitric oxide synthase gene in fertile and infertile women with endometriosis. This prospective study included a group of 52 women with a laparoscopic diagnosis of endometriosis. DNA was extracted from blood obtained from 47 patients and analyzed by PCR. The overall cohort was divided into infertile (n = 24) and fertile (n = 23) subgroups and compared in terms of genotypic and allelic frequencies. The genotypic distribution followed Hardy-Weinberg equilibrium (c2 = 2.21, P = 0.137) and included the GG genotype in 28/47 GT in 14/47, and TT in 5/47 of the samples. Genotypic and allelic frequencies between fertile and infertile women with endometriosis showed that absence of the TT genotype was associated with fertility in endometriosis patients (P = 0.0623). The T allele was present in 17 patients of the infertile group and 7 patients of the fertile group (P = 0.025). This allele was significantly associated with infertility (relative risk = 2.21, 95% confidence interval 1.56 - 3.08) for the recessive model of inheritance. Our findings suggest that women with endometriosis and the G894T polymorphism in the endothelial nitric oxide synthase gene are at increased risk of infertility.
Corn is considered one of the most important crops in the world agricultural scenario. In order to improve production, it is crucial to understand and quantify the genetic variation involved in the phenotypic manifestation of this species. We characterized corn genotypes using a multivariate approach and examined canonical interrelations between characters of agronomic importance. The study was carried out in the 2016/2017 crop year in the southernmost state of Brazil, in the northwest region of Rio Grande do Sul. The treatments were composed of six open-pollinated corn genotypes (PL 712, PL 725, PL 796, PL 804 and PL 861). The experimental design was a randomized block with four replications. Analysis of variance revealed a significant difference at 5% of probability by the F test for the attributes plant height, ear insertion height, stem diameter, ear length, number of seed rows per ear, number of seeds per row of ear, thousand seed weight, seed yield, percentage of germination, first germination count, emergency percentage and cold test. Genetic variability analysis showed genotype PL 712 to have superior seed productivity. The physiological quality of the seeds produced was variable among the genotypes, but it followed the trend of superiority for PL 712. Linear associations revealed a tendency for tall stature plants to increase seed yield of open pollinated corn. The most polymorphic characters were plant height and ear insertion, response to cold test, and thousand seed weight. The productivity and seed quality trends that were observed will allow us to plan further research on open pollinated varieties to allow selection and development of superior genotypes for seed productivity and quality in the extreme south of Brazil.
Several genes have been identified as important in athletic performance. The angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism has been related to improvements in performance and exercise duration. However, there are large divergences among studies on the influence of ACE I/D polymorphism on physical performance. Other studies have demonstrated that strenuous exercise generally overloads the endogenous antioxidant system’s capacity, leading to oxidative damage to muscles and other tissues in athletes. Few studies have reported significant associations between glutathione S-transferase (GST) deletion polymorphisms and resistance performance in athletes. We examined the effects of ACE I/D and GST deletion polymorphisms in young soccer players in central Brazil. We included 65 soccer players from under-20 (18 to 20 years old) soccer teams and 60 non-athletes in a case-control study. All subjects had their physical performance investigated through the Running-based Anaerobic Sprint Test (RAST). Genotyping was performed using real-time PCR. We found that the I/D genotype was significantly more frequent in athletes compared with the non-athletes. Individuals with the ID and DD genotypes had an approximately 3.13-fold and 4.37-fold increase in strength and power-orientated performance, respectively. The DD genotype in athletes presented RAST-test results considered as excellent to good when compared with non-athletes. When we examined a possible association of the GST deletion polymorphisms and RAST test, we found no influence on athletic performance. We did find association between ACE I/D polymorphism and athletic performance. However, there was no association between GST polymorphisms and risk of oxidative damage in the muscles. Our findings may help to select young players with the most favorable genetic potential to succeed as soccer athletes.
The search for genetic material of snap beans with desirable yield traits is of utmost importance for yield increase in Brazil. We evaluated 12 snap bean genotypes by diallel crosses that presented characteristics of interest, so as to select the best genitors to generate productive populations in the snap bean breeding program of the Universidade Estadual do Norte Fluminense in Rio de Janeiro state, Brazil. Diallel crosses were performed applying Method 2 of Griffing. The F1 generation, composed of 36 hybrid combinations, was evaluated in a greenhouse, in a completely randomized design with two replicates. The traits evaluated were: pod weight, length, width and thickness, number of seeds and seed weight. There were significant differences among genotypes for most variables, indicating genetic variability between snap bean lines. The following genitor genotypes proved to be the most suitable when the trait to be improved was yield: Top Seed Blue Line, UENF 1445, UENF 7-20-1, and UENF 7-10-1. The hybrids with higher values of combining ability estimates are indicated to generate promising segregating populations. Thus L3 (Top Seed Blue Line) × L18 (UENF 9-24-2), and L12 (UENF 7-14-1) × L1 (UENF 1445) hybrid combinations showed the best estimates of specific combining ability for the traits under evaluation, suggesting a high probability of obtaining superior genotypes. The efficiency of selection for these traits is based on additive genic action and demonstrates progress in the of snap bean breeding program.
Strawberry (Fragaria x ananassa) stands out among small fruits as the most planted in Brazil, generating considerable income and employment. However, producers are dependent on cultivars originating from international breeding programs and imported seedlings. This entails high costs and plants poorly adapted to the edaphoclimatic conditions of Brazil. In addition, the consumer market demands superior organoleptic and nutritional qualities. We assessed the potential of 194 hybrids for production and physicochemical characteristics from a population of seedlings obtained from intraspecific crosses of the short-day cultivars Dover, Camarosa, Sweet Charlie, Oso Grande, Milsei Tudla, and Festival Florida and the day-neutral cultivar Aromas. The experimental design was an augmented block design that had as control treatments the cultivars Camarosa and Camino Real. Five production and nine physicochemical characteristics were assessed. The mean comparison was performed by the Dunnett test. Among the 14 characteristics analyzed, eight presented significance. The significant production characteristics were the number of commercial fruits, mass of commercial fruits, mass of non-commercial fruits, and the total mass of fruits, with values of 45.03 fruits/plant, 13.17 g, 72.22 g/plant, and 720.77 g/plant, respectively. The physicochemical characteristics that varied significantly were soluble solids to titratable acidity ratio, pectin, ascorbic acid, and anthocyanin, which presented values of 10.23, 2.06 g total pectin/100 g pulp, 71.12 mg ascorbic acid/100 g pulp, and 39.51 mg cyanidin 3-glycoside/100 g pulp, respectively. The crosses that involved Camarosa and Aromas gave a greater number of hybrids with superior positive effects when compared to the controls in terms of production and physicochemical characteristics, respectively. Among the 194 hybrids, 30 were superior to the controls and were selected to advance in the breeding program.
Inheritance of fertility traits in cattle is complex since they are controlled by multiple loci. Genome-wide association studies are an efficient tool to detect genomic regions that explain the phenotypic variation for a trait of interest. The aim of this study was to identify genomic regions that affect the age at first calving (AFC) and the calving interval (CI) in the Romosinuano (ROMO) and Costeño con Cuernos (CCC) creole cattle breeds and nominate candidate genes that influence these reproductive traits. AFC and CI records were obtained from 4,063 ROMO and 3,922 CCC, and a total of 962 animals were genotyped using the BovineSNP50. Based on the single-step GBLUP methodology, the effects of 54K single nucleotide polymorphisms (SNPs) were grouped within windows of eight adjacent SNPs to explain the genetic variance. Sixty-six SNP windows were significantly associated with AFC (31 regions) and CI (35 regions). Of these regions, 17 were associated with AFC in ROMO, 14 with AFC in CCC, 17 with CI in ROMO and 18 with CI in CCC. From these, nine candidate genes (CACNA1A, CACNA1D, CACTIN, IARS2, PGRMC2, PTGDR, SYT10, UBE4A, RNF17) were identified as possible candidates involved in molecular mechanism that affect physiological mechanisms, such as hormonal regulation, ovarian cyclicity, growth rate, gametogenesis, acceleration of puberty, regulation of immune system, early embryonic development and the pathways to embryo-maternal recognition and maintenance of pregnancy. Furthermore, some genomic regions located in BTA1, BTA5 and BTA14 showed a pleiotropic effect on both AFC and CI. The polymorphisms identified in this study can help determine gene networks involved in the physiology of reproduction in cattle and to explain the inherent genetic variance of traits that measure reproductive performance in cattle. Some of these polymorphisms might be considered for breeding selection strategies to improve complex traits such as AFC and CI in beef and dairy cattle production systems.
Several theories have been proposed to explain the etiology of adolescent idiopathic scoliosis (AIS), but none is conclusive. One such theory suggests the primary involvement of muscles due to myopathy, mainly affecting the erector and paravertebral rotator muscles. Studies indicate that there may be an association of AIS with genetic polymorphisms previously associated with physical performance and muscle power through their effects on muscle tissue. One of these is the gene coding for the angiotensin converting enzyme (ACE). We compared the expression of ACE gene polymorphisms in the concave and convex sides of the scoliotic curve in patients with AIS. We evaluated ACE gene expression in the multifidus muscles of the spine of 21 patients operated for AIS correction who had signs of asymmetric myopathy (worse in the concavity). Tissue samples were collected during corrective surgery. There was no significant difference in ACE gene expression in multifidus muscle samples from the two sides of the apex of the thoracic AIS deformity. There were also no differences in the expression of insertion/deletion polymorphisms.
Sickle cell anemia is one of the most common genetic diseases in Brazil. This disease has an autosomal recessive inheritance pattern with a point mutation on chromosome 11, which is the substitution of an adenine by thymine. This mutation leads to the exchange of a glutamic acid for a valine at residue 6 of the beta globin chain, resulting in an abnormal form of hemoglobin, the so-called hemoglobin S (Hb S). The polymerization of Hb S produces reactive oxygen species, oxidizing agents that promote the oxidation of macromolecules, such as lipids, proteins and DNA. GSTs are enzymes that participate in the conjugation reactions of glutathione to a variety of electrolytic compounds that are potentially toxic and carcinogenic. The We analyzed the GSTT1 and GSTM1 gene polymorphisms in a patient with sickle cell anemia in order establish a more efficient clinical approach to treat the patient. The patient under study was 11 years old and sickle cell anemia was confirmed by the Guthrie test. Polymorphism identification was performed by PCR. The genotype identified in the patient was null for GSTT1 and present for GSTM1. In addition, the patient has a recurrent need for blood transfusion.
Endometriosis is a pathology that affects women in Brazil and around the world. It is characterized by the presence of endometrial cells outside the uterine cavity, leading to chronic pain, infertility and hormonal cycle deregulations. Ectopic endometrial foci may be responsible for changes in anatomy, in hormonal metabolism, immune and inflammatory systems and the pelvic peritoneum, causing pain and infertility. CYP2C19 is an important gene of the cytochrome p450 family that encodes an aromatase associated with estrogen metabolism. The CYP2C19*3 polymorphism is related to a higher susceptibility for endometriosis in women. This gene is overexpressed in chronic inflammation. The CYP2C19 gene is associated with drug metabolism, detoxification of potential carcinogenic agents and steroid metabolism . We analyzed the prevalence of the CYP2C19*3 polymorphism in women with endometriosis. The control group comprised 14 health women and the case group 19 patients with endometriosis. We found that the CYP2C19*3 polymorphism at a significantly higher rate in endometriosis patients. No individual in the control group presented had this polymorphism and we found no association between this polymorphism and any social habits in patients with endometriosis.