ABSTRACT
ABSTRACT: The objective of this paper was to estimate the genetic divergence among 49 soybean ( Glycine max L. Merrill .) genotypes to assist grain quality-focused breeding programs in the choice of progenitors. The genetic divergence was estimated using the Mahalanobis generalized distance from the percentages of protein, oil, and fatty acids oleic, linoleic and linolenic after cultivation of genotypes in different environments. Genotypes were grouped by agglomerative methods and the two and three-dimensional projections of the distance matrix were obtained. The average protein and oil contents in the four environments ranged from 34.25 to 45.18% and from 16.48 to 23.01%, respectively. The average contents of the fatty acids oleic, linoleic and linolenic ranged from 20.2 to 42.41%, from 44.17 to 63.18%, and from 5.89 to 10.39%, respectively. The genetic distances ranged from 0.11 to 251.02 and indicated genetic variability among the accessions. The most divergent pair of accessions was PI417360/CD01RR8384, followed by PI417360/B3PTA213-3-4 and PI417360/BARC-8. The most similar par of accessions was CS3032PTA276-1-2/CS3032PTA190-5-1, followed by UFV18/M-SOY8914 and BRSMG Garantia/CD983321RR. In this study we indicated as promising in terms of genetic variability the hybridizations involving BARC-8, CD2013PTA, CD01RR8384, CS303TNKCA, PI181544, and PI417360. Among these genotypes we can stand out BARC-8 and CD2013PTA, with protein contents above 43%, and CD01RR8384 and CS303TNKCA, with oil contents above 20%. The use of these genetically divergent genotypes and with high phenotypic means in future crosses should produce desirable recombinants for grain quality.
RESUMO: O objetivo deste trabalho foi estimar a divergência genética entre 49 genótipos de soja ( Glycinemax L. Merrill.), visando auxiliar programas de melhoramento voltados à qualidade do grão na escolha de progenitores. A divergência genética foi estimada por meio da distância generalizada de Mahalanobis a partir dos percentuais de proteína, óleo e ácidos graxos oleico, linoleico e linolênico após cultivo dos genótipos em diferentes ambientes. Os genótipos foram agrupados por métodos aglomerativos e as projeções bi e tridimensional da matriz de distância foram obtidas. Os teores médios de proteína e óleo nos quatro ambientes variaram de 34,25 a 45,18% e de 16,48 a 23,01%, respectivamente. Os teores médios dos ácidos graxos oleico, linoleico e linolênico variaram de 20,2 a 42,41%, de 44,17 a 63,18% e de 5,89 a 10,39%, respectivamente. As distâncias genéticas variaram de 0,11 a 251,02 e indicaram variabilidade genética entre os acessos. O par de acessos mais divergente foi PI417360/CD01RR8384, seguido por PI417360/B3PTA213-3-4 e PI417360/BARC-8. Já o par de acessos mais similar foi CS3032PTA276-1-2/CS3032PTA190-5-1, seguido por UFV18/M-SOY8914 e BRSMG Garantia/CD983321RR. Neste estudo, são indicadas como promissoras em termos de variabilidade genética as hibridações envolvendo BARC-8, CD2013PTA, CD01RR8384, CS303TNKCA, PI181544 e PI417360. Dentre esses genótipos, destacam-se BARC-8 e CD2013PTA, com teores proteicos acima de 43%, e CD01RR8384 e CS303TNKCA, com teores de óleo acima de 20%. A utilização desses genótipos geneticamente divergentes e com elevadas médias fenotípicas em futuros cruzamentos deverá produzir recombinantes desejáveis para a qualidade do grão.
ABSTRACT
As lipoxigenases (LOX) são responsáveis pelo "beany flavor", sabor característico da soja [Glycine max. (L.) Merrill], que é o maior obstáculo ao consumo da soja nos países ocidentais. O inibidor de tripsina Kunitz (KTI) é responsável por 80 por cento da inibição da atividade tríptica, além de provocar hiperplasia pancreática em animais monogástricos. Essas duas características são muito importantes em programas de melhoramento que visam à melhoria da qualidade da soja. Objetivou-se, neste trabalho verificar o efeito do inibidor de protease (KTI), sobre níveis de LOX em sementes de soja, nos seguintes genótipos: KTI+/LOX+, KTI+/LOX-, KTI-/LOX+ e KTI-/LOX-. As LOXs foram identificadas por teste colorimétrico, atividade enzimática e eletroforese em gel de poliacrilamida. O teor de proteína foi quantificado pelo método do ácido bicinconínico para determinação da atividade específica de LOX. Observou-se que, para o genótipo KTI+/LOX+, a atividade específica de LOX 1 foi alta, variando de 177,92 a 206,94 UA/mg de proteína e para LOX 3 variou de 17,90 a 19,85 UA/mg de proteína; para KTI+/LOX- e KTI-/LOX- não foi detectada atividade de LOX e que para o genótipo KTI-/LOX+ a atividade específica para LOX 1 variou de 117,24 a 124,64 UA/mg de proteína, e de 17,35 a 20,29 UA/mg de proteína para LOX 3. Houve uma redução de 40 por cento na atividade específica de LOX1 e de 1 por cento para LOX 3, no genótipo KTI-/LOX+, quando comparados ao KTI+/LOX+. Esses resultados comprovam uma associação negativa entre o inibidor de tripsina Kunitz e a atividade de lipoxigenases.
Lipoxygenases (LOX) are responsible for the beany flavor, which is the most important obstacle for the consumption of soybean [Glycine max. (L.) Merrill] products in Western countries. The Kunitz trypsin inhibitor (KTI) is responsible for 80 percent of the inhibition of tryptic activity in soybean seeds, and besides it can cause pancreatic hyperplasia in monogastric animals. These two traits are very important in soybean breeding programs that aim the improvement of soy protein quality. The objective of this study was to verify the influence of KTI on LOX levels in soybean seeds by analyzing the following genotypes: KTI+/LOX+, KTI+/LOX-, KTI-/LOX+ and KTI-/LOX-. LOX 1 and LOX 3 were identified by colorimetric, activity and electrophoretic assays. Protein content was determined by the bicinchoninic method for determination of LOX specific activity. For genotype KTI+/LOX+, LOX 1 specific activity was high varying from 177.92 to 206.94 AU/mg of protein and LOX 3 activity varied from 17.90 to 19.85 AU/mg of protein. No LOX activity was detected in genotypes KTI+/LOX- and KTI-/LOX-. For genotype KTI-/LOX+, LOX 1 activity varied from 117.24 to 124.64 AU/mg of protein, and the activity of LOX 3 from 17.35 to 20.29 AU/mg of protein. There was a reduction of 40 percent on LOX 1 specific activity and 1 percent for LOX 3 in the KTI-/LOX+ genotype in comparison to genotype KTI+/LOX+. These results indicate an inverse relationship between the presence of the Kunitz trypsin inhibitor in soybean seeds and lipoxygenase activity.
ABSTRACT
Various population sizes and number of markers have been used to obtain genetic maps. However, the precise number of individuals and markers needed for obtaining reliable maps is not known. We used data simulation to determine the influence of population size, the effect of the degree of marker saturation of the genome, and the number of individuals required for mapping of recombinant inbred lines (RILs). Three genomes with 11 linkage groups were generated with saturation levels of 5, 10 and 20 cM. For each saturation level populations were generated with 50, 100, 154, 200, 300, 500 and 800 individuals with 100 replications for each population size. A total of 2100 populations was generated and mapped. Small marker numbers and small population sizes produced maps with more than 11 linkage groups. As population size and marker saturation increased, marker inversion and non-linked markers decreased, moreover, between-marker distance estimates were improved. In this study, a minimum size of 200, 300 and 500 individuals were necessary for obtaining reliable maps when they were evaluated over the saturation levels of 5, 10 and 20 cM, respectively.
ABSTRACT
Genetic diversity and the relationship between varieties are of great importance for cotton breeding. Our work was designed to estimate the informativeness of the cotton (Gossypium hirsutum L.) simple sequence repeat (SSR) microsatellite locus and to estimate the genetic distance between 53 cotton cultivars as well as to select a set of SSR primers able to differentiate between the 53 cotton cultivars studied. After extracting DNA from the 53 cultivars and characterized it using 31 pairs of SSR primers we obtained a total of 66 alleles with an average of 2.13 alleles per SSR locus and values of polymorphism information content (PIC) varying from 0.18 to 0.62, the dissimilarity coefficient varying from zero to 0.41. Statistical analysis using the unweighted pair-group method using arithmetic average (UPGMA) revealed seven subgroups which were consistent with the genealogical information available for some of the cultivars. The SSR genetic profile obtained for each of the cultivars made it possible to discriminate 52 of the 53 cultivars. This study of the genetic diversity of cotton cultivars with SSR markers support the need to introduce new alleles into the gene pool of the breeding cultivars.
Subject(s)
Genetic Variation , Gossypium/genetics , Microsatellite Repeats , Minisatellite Repeats , Polymorphism, Genetic , Random Amplified Polymorphic DNA Technique , Data Interpretation, StatisticalABSTRACT
OBJETIVO: Avaliar a qualidade protéica de farinhas de soja, que diferem entre si com relação à presença de lipoxigenases e/ou Inibidor de Tripsina Kunitz. MÉTODOS: Procedeu-se aos ensaios biológicos com ratos, em que foram avaliados a Razão da Eficiência Protéica, Razão Protéica Líquida, Utilização Protéica Líquida e a digestibilidade. Determinou-se a composição aminoacídica das farinhas e cálculo do Escore Químico Corrigido pela Digestibilidade. RESULTADOS: Os valores de Razão da Eficiência Protéica, Razão Protéica Líquida, Utilização Protéica Líquida para as variedades de soja foram inferiores aos valores obtidos para caseína. Para as farinhas sem Inibidor de Tripsina Kunitz foram obtidos valores de digestibilidade maiores que para as farinhas com Inibidor de Tripsina Kunitz, e esses foram bem próximos aos da caseína. Com relação ao teor aminoacídico, constatou-se que o aminoácido limitante dessa soja é lisina e não metionina, ao contrário do que aponta a literatura. CONCLUSAO: A eliminação genética do Inibidor de Tripsina Kunitz melhora consideravelmente a digestibilidade da proteína de soja. Os resultados do Escore Químico Corrigido pela Digestibilidade não indicaram diferença entre as farinhas sem Inibidor de Tripsina Kunitz das farinhas derivadas de linhagens com Inibidor de Tripsina Kunitz, como foi observado pelos resultados da digestibilidade in vivo.
Subject(s)
Animals , Rats , Plant Proteins, Dietary , Trypsin Inhibitor, Kunitz Soybean , Lipoxygenase , Glycine max/chemistry , Glycine max/enzymology , FlourABSTRACT
Seven soybean cultivars (Bossier, Cristalina, Davis, Kent, Lincoln, Paraná and Uberaba), with different levels of resistance to Cercospora sojina, race 04, were crossed according to a diallel design, with no reciprocals, to determine the general and the specific combining abilities for the resistance. The evaluations of the reaction to the disease were performed 20 days after the inoculation of the fungus on the most infected leaflet of the plant, in the parents and in the F1 hybrids. To quantify the resistance, the following characteristics were evaluated: infection degree (ID); number of lesions per leaflet (NLL); lesion mean diameter (LMD); lesioned leaf area (LLA); percentage of lesioned leaf area (PLLA); number of lesions per square centimeter (NLC) and disease index (DI). The relative importance of each characteristic was evaluated by the canonical variables analysis and the LLA and NLL characteristics were eliminated from the multivariate function. With the remaining five characteristics, a multivariate index was created using the first canonical vector, which was submitted to the diallel analysis, according to Griffings fixed model, method 2. The most important characters to discriminate resistant from susceptible soybean plants to C. sojina were: ID, LMD, NLC, DI and PLLA. Cristalina, Davis and Uberaba cultivars are the best ones among those tested that can be recommended as parents in soybean breeding programs seeking resistance to Cercospora sojina. The additive, dominant and epistatic genetic effects were important for the expression of the resistance, although the additive genetic effect was the most important component.
Subject(s)
Fungi , Glycine max , Multivariate AnalysisABSTRACT
The genetic reduction of linolenic acid levels increases the quality and stability of soybean oil. The objective of this study was to determine the inheritance and evaluate the nature and magnitude of gene effects on soybean seed linolenic acid level. Means and variances of F-1, F-2, and F-3 generations were made from the cross between accession BARC-12 (low linolenic acid content) and the commercial Brazilian cultivar CAC-1 (normal linolenic acid content). The results demonstrated that linolenic acid content in soybean is under the genetic control of a small number of genes. The additive model explained the means for the three generations and for the parents. Non-allelic gene interactions had little effect on the determination of genotypic values for the individuals. The generation means and population variation analyses demonstrated that the dominance deviations contribute little to the trait. These results showed that backcross breeding programs can be used to introduce the low linolenic acid content trait into soybean seeds, since it is possible to identify with very high accuracy the desired genotypes in segregating populations
Subject(s)
Biometry , Glycine max/genetics , Linolenic AcidsABSTRACT
The soybean (Glycine max (L.) Merrill) frogeye leaf spot is caused by the fungus Cercospora sojina Hara and is a widespread disease in Brazil and other countries, causing severe losses in grain yield and also affecting seed quality. The availability of DNA markers linked to genes for resistance to this disease would accelerate breeding programs, particularly when other traits are also being evaluated. Bulked segregant analysis was applied to 3 F2 populations derived from crosses between the resistant cultivars Parana, Cristalina and Uberaba, and the susceptible cultivar Bossier. In the cross 'Parana' x 'Bossier', 2 RAPD markers were identified, CSOPA1800C and CSOPA21,250C, located at 4.4 1.8 centiMorgans (cM) and 3.4 1.7 cM respectively from the resistance locus. DNA fragments of similar molecular weight were observed in the population derived from the cross 'Cristalina' x 'Bossier' at 2.3 1.2 and 4.7 1.5 cM from the resistance locus, respectively. In the offspring of the cross 'Uberaba' x 'Bossier', a DNA fragment corresponding to marker CSOPA1800C was detected at 5.6 2.1 cM from the resistance locus. Although marker CSOPA21,250C was not observed in this population, an additional marker was detected (CSOUB11,100C) at 6.7 2.2 cM from the resistance locus. The 1,250 bp fragment of CSOPA21,250C was cloned and converted into a SCAR marker, which amplified a single fragment whose size corresponded to the cloned segment of the crosses involving cultivars Cristalina and Parana. Markers CSOPA1800C, CSOPA21,250C and CSOUB11,100C were mapped to soybean linkage group J with the aid of known SSRs linked to the Rcs3 locus, indicating that the RAPD and SCAR markers identified in our research also tag this resistance gene
Subject(s)
Glycine max/microbiology , Fungi , Biomarkers , Plant DiseasesABSTRACT
We have started a breeding program to genetically eliminate the lipoxygenase isozymes (LOX) from soybean seeds. These enzymes are believed to be the main cause of off-flavors in soybean products. LOX are present in the seed as three isozymes encoded by three different genes, which are inherited in a simple mendelian fashion. Mutants lacking each one of these isozymes have been identified in the world germplasm. To introduce these null alleles into the Brazilian variety Cristalina, three mutant progenitors were chosen: PI 408.251 (LOX1 minus), PI 86.023 (LOX2 minus), and Ichigowase (LOX3 minus). The random amplified polymorphic DNA (RAPD) technique was used to charactetize these progenitors, as well as lines lacking LOX1 (CR1), LOX3 (CR3), LOX1 and 3 (CR1,3), and LOX2 and 3 (UFV 91-263, UFV 91-401 and UFV 91-717). The results enabled us to establish the fingerprint of each genotype and the genetic distances among them.
Subject(s)
Glycine max/genetics , Lipoxygenase , Random Amplified Polymorphic DNA Technique , Chromosome Banding , GenotypeABSTRACT
O fungo termo-celulolítico Humicola sp apresentou alta atividade de exo-ß-D-glucanase (C1) ligada a célula e baixa atividade de endo ß-Glucanase (Cx) ligada a célula e no sobrenadante. Celulose microcristalina foi melhor indutor de celulase e melhor fonte de carbono do que carboximetil celulose. A atividade de ß-glucosidase foi medida somente so sobrenadante da cultura e seu valor foi maior quando carboximetil celulose foi usada como fonte de carbono em pH 7.0
Subject(s)
Trichoderma/enzymology , Carboxymethylcellulose Sodium/metabolism , Cellulase/metabolism , Cellulose/metabolism , Trichoderma/metabolism , Glucosidases/metabolismABSTRACT
A espécie termofílica do fungo Humicola sp, capaz de crescer em celulose como fonte de carbono, foi isolada de composto. O fungo apresentou melhor crescimento a temperatura de 40-C e pH 6.0. A ausência de K+ ou a presença de citrato a 10mM em meio de cultura inibiram seu crescimento. A inibiçäo na presença de citrato foi devida a seu efeito quelante de Mg++. O fungo foi capaz de utilizar as seguintes fontes de carbono: acetato, ágar-ágar, amido, carboximetilcelulose, celobiose, glucose, lactose, manose e xilose
Subject(s)
Cellulose/metabolism , Citrates/metabolism , Colony Count, Microbial , Temperature , Yeasts/growth & development , Yeasts/enzymology , Carbon/analysis , Culture MediaABSTRACT
A soybean breeding program has been undertaken at the Federal University of Viçosa aiming to reduce lipoxygenase lelvels ib the seeds of commercial varieties. A direct ELISA (Enzyme Linked Immunosorbent Assay) procedure has been developed to quantify lipoxygenases L1 and L2 in soybean seeds. Polyclonal antibodies were reised in rabbits against pure L1 and L2 and purified further by affinity chromatography. The best conditions to perform the analaysis were determined as foloow: coating antibody dilution 1:100, crude soybean protein extract 1:2 x 105 and conjugate 1:100 for both L1 and L2 isozymes. The method proved to be sensible enough to identify homozygous and heterozygous genotypes in the breeding program performing single non destructive analysis of seeds or even cotileldones right after germination. Besides, L1 was quantified in about 120 soybean Brazilian cultivars an L2 in some of them. The results showed a significant variability in the level of lipoxygenase-1 among the cultivars analysed. With respect to L2, it was found that the level of this isozyme was significantly greater in the seeds than observed for L1, in spite of its lower "in vitro" specific activity
Subject(s)
Glycine max/enzymology , Lipoxygenase/analysis , Enzyme-Linked Immunosorbent AssayABSTRACT
In the effort to genetically manipulate soybean seeds aiming to improve flavor quality toward human consuption, lipoxygenase null alleles are being transferred to a brazilian commercial variety. Immunochemical approach has been taken to perform analysus of hundred of seeds derived from the breeding program. For that reason lipoxygenases L1 and L2 were puridied to hemogeneity by gel filtration and affinity chromatography. Policlonal antibodies were prepared in rabbits and purified further by affinity chromatogrphy. By using the purified anti-L1 and anti-L2 an Ouchterlony double immunodifusion method has been developed in our lab to detect the presence/absence of the isozymes simultaneously in soybean seeds. The method proved to be highly specific and efficient enought to perform single non destructive seed analysis