Current issues

Table of contents: 2019

Research Article

Diallel analysis and field tests have not been used in selecting for resistance to fusarium wilt in common beans (dry beans, Phaseolus vulgaris). Our goal was to select parents and segregating populations of dry bean (common bean) with black seed coat that are resistant to fusarium wilt and have high yield and high seed weight. Eight common bean cultivars and elite lines with some level of resistance to fusarium wilt based on previous evaluations, were used to make crosses in a complete diallel scheme. The 28 populations obtained were evaluated with two controls in trials in the F3 (winter/2012), F4 (winter/2013), and F5 (winter/2014) generations in randomized blocks, with three replications, in plots of two 4-meter rows. The trials were conducted in Santo Antônio de Goiás, GO, Brazil, in a field infested by Fusarium oxysporum f. sp. phaseoli in the winter growing season. Data were obtained on reaction to fusarium wilt, yield, and 100 seed weight. Individual and joint analyses of variance and diallel analysis were conducted on these data regarding reaction to fusarium wilt. Mean values were clustered using the Scott-Knott test. Genetic variability was detected for the three traits. There were significant differences among the general combining abilities of the parents and specific combining abilities of the populations for reaction to fusarium wilt, and the additive and non-additive effects were significant. The CNFP 15867 line is recommended for performing new crosses, because it exhibited a positive estimate of general combining ability (0.39), which indicates that it contributes to obtaining more resistant populations. The populations BRS Esplendor x BRS Expedito and BRS Expedito x CNFP 15867 were the most promising for extraction of lines, because they present high resistance to fusarium wilt (-2.6 and -2.8) and high grain yield (2212 and 2270 kg.ha-1), and acceptable seed weight (21.1 and 20.5 g/100grains).

Genet. Mol. Res. 18(3): GMR18276
DOI: 10.4238/gmr18276
Research Article

The CYP2C19*2 polymorphism is the result of a point mutation leading to an alternative splicing defect, generating an enzyme with a reduced function. The enzyme CYP2C19 is responsible for the activation of the prodrug Clopidogrel and the loss of its function leads to an increase in platelet aggregation. We compared the ARMS-PCR (Amplification Refraction Mutation System) and RFLP-PCR (Restriction Fragment Length Polymorphism) to determine which of the techniques was more efficient for identifying the CYP2C19*2 polymorphism. We analyzed 200 samples from patients with atherosclerosis and 100 samples from a control group, free from the disease. The polymorphic allele was not observed in any of the samples analyzed by the ARMS-PCR technique, but was present in more than 70% of the samples when analyzed by RFLP-PCR. Thus, RFLP-PCR generated more satisfactory results for the analysis of CYP2C19*2 polymorphism, and it should be used, despite the lower cost of ARMS-PCR, as the latter did not detect this polymorphism. 

Genet. Mol. Res. 18(3): GMR18268
DOI: 10.4238/gmr18268
Research Article

Polycystic ovarian syndrome (PCOS) is the most prevalent endocrine disorder affecting females. It is a common cause of menstrual irregularities and infertility during a woman’s reproductive years. Many factors may play a crucial role in the pathogenesis of POCS. One of these factors is related to immunogenetics. Cytokines are significant immunomodulatory proteins for regulating and controlling cell functions involved in the immune system. The imbalance between pro- and anti-inflammatory pathways plays a role in PCOS etiology. We investigated the relationship between gene polymorphisms interleukin (IL-10) (rs1800871, rs1800872, rs1800896) and tumor necrosis (TNF-α) (rs1799724) in Saudi women with PCOS. The study group consisted of 93 Saudi females (mean age 31.05 ± 0.590, range 18 - 40 years) with PCOS. The control group consisted of 98 Saudi women without PCOS. Blood was obtained, and DNA was extracted for each patient and control. Single nucleotide polymorphisms (SNPs) of promoter regions were determined using Taq Man genotyping assays. The polymorphism frequencies in IL-10 (rs1800871) A/A, A/G, and G/G genotypes were 7.5%, 38.7%, and 53.76%, respectively in PCOS patients and 5.1%, 45.9%, and 49.0%, respectively in controls with no significant differences between the groups. No significant differences in IL-10 polymorphism frequencies in C/C, C/T, and T/T between groups were noted. No significant differences were seen between groups with respect to the sample parameters for TNF TNF-α. The differences in frequencies of alleles and genotypes were not significant between Saudi women with PCOS and controls. We conclude that though in some populations, meta-analyses showed an association between IL-10 and TNF-α gene polymorphisms and PCOS, this association is not apparent in Saudi females.

Genet. Mol. Res. 18(3): GMR18270
DOI: 10.4238/gmr18270
Research Article

Cassava (Manihot esculenta) is a traditional crop in tropical and subtropical regions that is used for human consumption and in animal feed. This studied cassava landraces cultivated in northern Mato Grosso State, Brazil, to detect the variability in family farms, aiming at the preservation and use potential of these genetic resources. A total of 120 M. esculenta individuals were evaluated at the rate of 40 per location (population), where each landrace was represented by 10 plants. The 14 microsatellite markers examined showed genetic diversity. The average polymorphic information content (PIC) was 0.621 and the average number of alleles per locus was seven. Genetic diversity parameters indicated that Ho was higher than He for the three populations, showing negative fixation indices and a lack of inbreeding. AMOVA revealed greater molecular variation within the populations (92%). Bayesian analysis and the UPGMA clustering method resulted in two main groups formed with the individuals distributed randomly; i.e., regardless of collection site (location). The gene flow found in this study is a consequence of the introduction and exchange of genetic material (landraces) performed by the farmers, who act on their farms as maintainers of local diversity. Manihot esculenta cultivation in northern Mato Grosso State ensure the on-farm conservation of genetic variability of the species and constitutes a source of genetic resources such as genes of resistance and adaptation, which can be exploited and utilized in breeding programs.

 

Genet. Mol. Res. 18(3): GMR18315
DOI: 10.4238/gmr18315
Research Article

Anacardium occidentale (cashew) is a tropical tree species that occurs mainly in northeastern Brazil. The species has great socioeconomic importance for rural populations. We investigated the genetic diversity of a natural cashew population in a rural area of ​​Floriano, State of Piauí, Brazil. We quantitatively evaluated 12 natural variables related to the inflorescence, the cashew nut (fruit), and the peduncle (pseudofruit) in 35 trees (numbered sequentially G1-35). The characteristics of the peduncle (pseudofruit) appeared as the variables that most contributed to genetic divergence, while characteristics related to the inflorescence contributed less to the morphological differentiation. Multivariate statistics, employing principal component analysis evidenced that the first three principal components explained 81.72% of the total variance. Cashews G-3 and G-8 were identified as the most divergent, with G-3 demonstrating the greatest peduncle lengths and weights.

 

Genet. Mol. Res. 18(3): GMR18348
DOI: 10.4238/gmr18348
Research Article

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 evaluated the agronomic performance of open pollinated genotypes, used by small scale family farmers, compared to commercial hybrid genotypes in various growing environments. The experimental design was a randomized block and the treatments were arranged in four replicates. Eight maize genotypes were used: three open-pollinated varieties and five simple hybrids. The following characters were measured plant height, ear insertion height, stem diameter, ear length, number of seed rows of the ear, number of seeds per row of ear, thousand seed weight and seed yield. The best yields of seeds were obtained in Entre-Ijuís, RS. Seed yield varied according to the genotype and growing environment; in Pelotas, RS the highest yields were obtained with the HC2 and HC1 genotypes (9090 and 9002 kg.ha-1, respectively). Genotypes with a narrow genetic base express less variation in their responses to the environments, in contrasting environments. Under limiting conditions the open pollinated varieties responded favorably. The use of biometric approaches allows us to reveal patterns in the grouping of genotypes.

Genet. Mol. Res. 18(3): GMR18180
DOI: 10.4238/gmr18180
Research Article

The angiotensin-converting enzyme (ACE) insertion (I)/deletion (D) polymorphism could influence predisposition for diabetic nephropathy (DN) by vascular modulation in the kidney, through a direct effect on cellular hypertrophy. However, studies on the association between this polymorphism and DN report conflicting results. To help determine if this association exists, we conducted a meta-analysis. Published studies until 2018 were researched from electronic databases PubMed/NCBI and Cochrane Library. Thirty studies including 4774 DN cases and 4357 individuals without DN were included in this meta-analysis. Extraction of data from all eligible publications was performed by two investigators independently, according to the inclusion and exclusion criteria. We used the statistical software “R” by the overall odds ratio (OR) with a 95% confidence interval to evaluate the association of ACE I/D polymorphism with a possible risk towards DN development. We included various genetic model analyses, sensitivity analyses, and assessments of bias in our meta-analysis. We found a significant association for ACE I/D polymorphism; the D allele is a predisposing factor for DN in diabetic patients. The risk for development of diabetes complications, such as DN, is highly complex and could be considered multifactorial. In summary, our meta-analysis shows that the ACE I/D polymorphism is associated with susceptibility to DN.

 

Genet. Mol. Res. 18(3): GMR18378
DOI: 10.4238/gmr18378
Research Article

Efficient analysis of datasets from multi-environment trials (MET) is of paramount importance in plant breeding programs. Several methods have been proposed for this purpose, each of them having advantages and disadvantages, depending on the objectives of the study. We examined the robustness in the predictive power of models that have been widely used in the study of genotype-by-environment interaction such as AMMI (additive main-effects and multiplicative interaction) models via EM algorithm, Bayesian AMMI models with homogeneity (BAMMI), heterogeneity of variances (BAMMI-H) and the Analytical Factorial model (FA). To check the efficiency of these methods, genotype and genotype- by- environment interaction effects were simulated and further unbalances were included at levels of 10, 33 and 50% loss of genotypes in the environments. To evaluate the predictive power of the proposed models, the PRESS (prediction error sum square) statistics and the Cor (correlation between predicted and observed value) were used. The genotype-environment interaction models had low sensitivity to missing data since all models showed correlations above 0.5 in all scenarios - even with high unbalance levels (50%). In general, there were differences in predictive accuracy among the models in different scenarios, with a slight advantage for the Bayesian models in the correlation among observed and predicted data ranging from 0.79 to 0.855 compared to 0.591 to 0.853 obtained from the competing models. Similar results were observed for the PRESS (4.988 to 8.027) in Bayesian models compared to competing models (5.411 to 23,361). Overall, there was slight advantage of the Bayesian models in unbalanced scenarios.

 

Genet. Mol. Res. 18(3): GMR18176
DOI: 10.4238/gmr18176
Research Article

Deterioration and loss of seed germination in the germplasm are related to the aging that occurs during the conservation process. The mechanisms related to the aging and death of seeds are not yet fully understood, but it is known that longevity can be affected by moisture content and temperature. We examined the effects of accelerated aging (A.A.) on the DNA of seeds of three different cultivars of cowpea (Vigna unguiculata) and compared the data to data from vigor and germination tests. The DNA of A.A.-seeds of BR 17 Gurgueia, BRS-Marataoã and BRS-Guariba cowpea cultivars were extracted and subjected to agarose gel electrophoresis. The increase in temperature, relative humidity and time used in A.A. culminated in a progressive and increasing degradation of seed DNA, which was expressed by continuous bands of DNA molecules with different lengths in the electrophoresis gel under all but the most extreme conditions (combinations 45°C/72 h and 45°C/96 h at 100% relative humidity) under which total disintegration of the  DNA band was observed. This, in turn, was reflected in a progressive decrease in seed vigor. The combination of 35ºC/48 h was the most efficient for evaluating vigor in cowpea. The BR 17 Gurgueia and BRS-Guariba cultivars showed the highest values of vigor. A lack of DNA degradation in the laddering pattern on an electrophoresis gel is an indicator that DNA degradation and cell death in cowpea seeds did not occur by apoptosis but by non-programmed processes, such as Maillard reactions, lipid peroxidation and hydrolysis of sugars.

Genet. Mol. Res. 18(3): GMR18304
DOI: 10.4238/gmr18304
Research Article

The common bean is widely distributed throughout Brazil and within Mato Grosso state. It has wide genetic variability and adaptability to various environmental conditions. We evaluated the genetic divergence and agronomic performance of common bean genotypes in order to initiate a bean breeding program in the region of Cáceres, MT. We included 58 genotypes (40 traditional accessions, 14 lines and four cultivars) using a randomized block design with three replications, at Empresa de Pesquisa, Assistência e Extensão Rural do Mato Grosso, evaluating 10 morphological and agronomic characteristics. The data were submitted to analysis of variance and cluster analysis based on Mahalanobis distance; we used the Tocher and UPGMA grouping methods to group to the genotypes. Through analysis of variance, we detected significant differences at 1% probability for all traits. The shortest genetic distance was found between genotypes 13 and 26 (= 1.51) as the most similar, while 20 and 4 ( = 346.00) were the most dissimilar. The Tocher and UPGMA clustering methods were similar in grouping the genotypes, with the most divergence in different groups. Crossing of the earliest genotypes (11, 13 and 16) with the improved genotypes (43 and 51) resulted in the greatest heterotic effect, increasing the likelihood of the emergence of superior genotypes in the progenies, which is beneficial for the initiation of the bean breeding program for the Cerrado region of Cáceres in Mato Grosso.

 

Genet. Mol. Res. 18(2): GMR18299
DOI: 10.4238/gmr18299
Research Article

Serum paraoxonase (PON1) and hemochromatosis (HFE) genes may play important roles in lead toxicity owing to their role in xenobiotic and iron metabolism, respectively. The association between PON1 and HFE genotypes and blood lead levels (BLLs) was examined in lead exposed subjects from Saudi Arabia. The polymorphisms at PON1 L55M, PON1 Q192R, HFE H63D and HFE C282Y (using PCR-RFLP) and their relation to BLLs was evaluated. The recruited subjects (N = 127) were categorized into low BLL group (<10 μg/dL) and high BLL group (>10 μg/dL) according to CDC guidelines. The low BLL group had a mean level of 3.94 µg/dL, while the high BLL group had levels of 15.33 µg/dL (P < 0.001). Overall, the genetic variants, TA and AA in the PON1 L55M were significantly (P = 0.00002 and P = 0.00322, respectively) associated with a risk of lead toxicity and the allele ‘A’ was a risk factor (P = 0.00002). However, the Q192R genotype of PON1 along with HFE H63D and HFE C282Y did not significantly increase the risk of developing lead poisoning. Our findings suggest that L55M gene polymorphism influences the susceptibility of subjects to lead exposure and thus it could be a useful biomarker of genetic susceptibility in assessing an individual’s risk of damage from heavy metal exposure.

 

Genet. Mol. Res. 18(2): GMR18317
DOI: 10.4238/gmr18317
Research Article

Several strategies have been employed in the breeding of passion fruit with a view to the generation of superior progeny. In an effort to develop more precise methods in breeding, we compared the efficiency of the Post-Hoc Blocking Row-Col technique, which is an a posteriori technique that consists of the overlapping of a block structure on the original-field design, with a randomized-block design and compared different selection strategies within and among half-sib families, using the REML/BLUP mixed-model methodology. Twenty-three half-sib families from the third cycle of recurrent selection of the breeding program of Universidade Estadual do Norte Fluminense Darcy Ribeiro - UENF were evaluated. The trial took place in the experimental unit of UENF, in Itaocara - RJ, Brazil. Plants were trained on vertical stakes, with four replicates and three plants per plot. They were assessed individually for the traits number of fruits per plant, fruit mass per plant, fruit length, fruit diameter, peel thickness, total soluble solids, pH, pulp percentage, and production per plant. No significant difference was found in the test of efficiency of the designs for any of the evaluated traits. Within-family heritability (h2ad) had a similar magnitude to individual heritability (h2a), indicating that even in the 4th cycle of recurrent selection, genetic variability still exists within the evaluated progeny. Selection within half-sib families provided superior gains when compared with selection among families for the traits number of fruits; production; fruit mass, length, and diameter; total soluble solids; pH; and pulp percentage. The best selection strategy was within families, as it generated higher selection-gain estimates than those obtained with selection between families and the direct-selection and index-selection approach.

Genet. Mol. Res. 18(2): GMR18305
DOI: 10.4238/gmr18305
Research Article

The development of common bean cultivars with upright plant architecture and high grain yield meets the needs of bean growers by facilitating culture management and mechanized harvest. The objectives of this study were to evaluate whether Mesoamerican common bean lines differ for upright plant architecture traits and grain yield, analyze correlations between these traits, and to select superior common bean lines based on a selection index. Four experiments were carried out in different years and growing seasons at low altitude (95 m above sea level) in southern Brazil. These experiments were composed of 17 carioca and black bean inbred lines, which are representative of the most widely produced and consumed common bean classes in Brazil. Upright plant architecture was assessed by 12 characters, and the resulting data were subjected to individual and joint analyses of variance, correlation, and selection index (rank sum). A significant effect for genotype and/or genotype x environment interaction was observed for all traits, except for the length of the first internode and hypocotyl diameter. Most plant architecture traits were correlated, indicating that it is possible to reduce the number of traits that need to be evaluated. Grain yield was negatively correlated with the lengths of the fourth (r = -0.574) and fifth internodes (r = -0.641). General adaptation score, insertion of the first pod, and lengths of the fourth and fifth internodes were efficient to characterize upright plant architecture in the common bean. Indirect selection by the shortest length of the fourth and fifth internodes was efficient to increase grain yield. The genotypes LP 11-117, SM 0312, BRS Valente, and Guapo Brilhante were selected based on a rank sum index. These genotypes present upright plant architecture and high grain yield, which is a common bean ideotype suitable for cultivation at low altitude in southern Brazil.

 

Genet. Mol. Res. 18(2): GMR18323
DOI: 10.4238/gmr18323
Research Article

VIRB proteins from Brucella spp. constitute the type IV Secretion System (T4SS), a key virulence factor that mediates the intracellular survival of these bacteria. We investigated the immunogenicity and protection of proteins produced by the virB9 and virB12 genes in the DNA vaccine and DNA prime-protein boost strategies. Groups of 10 mice were vaccinated with pcDNAvirB9, pcDNAvirB12, pcDNAvirB9+rVIRB9 or pcDNAvirB12+rVIRB12. The latter two groups were vaccinated with the proteins rVIRB9 and rVIRB12, respectively, during the third immunization. Three weeks after the last immunization, six animals from each group were challenged intraperitoneally with B. abortus strain S2308, and the efficacy of the vaccines was calculated as the log10 of protection by subtracting the mean log CFU of the vaccinated group from the mean log CFU of the negative control group (injected with sterile saline). Most of the vaccinated mice produced total IgG and the subclasses IgG1 and IgG2a against the respective protein, except for the mice vaccinated with pcDNAvirB12. Cytokines IFN-γ and IL-10 were produced, but without a significant difference between the vaccinated and negative control groups. The vaccines did not induce significant levels of protection, in contrast to the immunization obtained with the S19 vaccine strain (Log10, 1.48). In conclusion, the virB9 and virB12 genes of B. abortus, using DNA vaccine and DNA prime-protein boost strategies, were able to induce both humoral and cellular immune responses, but not enough to induce significant protection in the immunized mice. However, given the response in this system, further investigations using the virB9 and virB12 genes of Brucella spp., together with different immune modulators, are warranted. An effort should be made to direct and enhance the immune response, in order to identify a combination that stimulates a better immune response and, consequently, a better level of protection.

Genet. Mol. Res. 18(2): GMR18295
DOI: 10.4238/gmr18295
Research Article

Xanthomonas albilineans causes leaf scald disease, one of the most economically important diseases of sugarcane. Leaf scald is a systemic and vascular disease that can severely reduce productivity. The best and primary method of leaf scald control is the use of tolerant cultivars. Knowing that cell wall lignification is a plant defense mechanism and that chorismate mutase is relevant in this process, we analyzed the expression pattern of the chorismate mutase 2 (SoCM2) gene in two contrasting sugarcane cultivars by RT-qPCR.  A similar pattern of downregulation for the SoCM2 gene was observed in both cultivars; however, after 72h, the tolerant cultivar (RB867515) showed repression of the SoCM2 gene, while for the susceptible cultivar (SP78-4467), SoCM2 gene downregulation occurred only after 144h. Here we propose that early repression of the SoCM2 gene is responsible for tolerance to X. albilineans infection in the sugarcane cultivar RB867515.

 

Genet. Mol. Res. 18(2): GMR18262
DOI: 10.4238/gmr183262

Pages