Lactate dehydrogenase (LDH) isozyme 1 (B4), 5 (A4), and “X” (Testis or Sperm type) have been part... more Lactate dehydrogenase (LDH) isozyme 1 (B4), 5 (A4), and “X” (Testis or Sperm type) have been partially purified from mouse tissues.The following studies were carried out on the three isozymes: Km and optimum substrate concentration for pyruvate, α-oxo-butyrate, α-oxo-valerate, lactate, α-OH-butyrate, and α-OH-valerate, inhibition by substrate and product, effect of malate, N-(4-carboxy-2-hydroxyphenyl) maleimide, some citric acid cycle metabolites, urea, trypsin and pH.The mouse testicular LDH isozyme clearly differs from the common lactate dehydrogenases and from the tesficular isozymes from other species. It shows distinct sensitivity to inhibition by substrate or product whether the direct (pyruvate lactate) or reverse reactions are studied. There is no effect of increasing concentrations of pyruvate or lactate on the direct reaction, while a clear inhibition by lactate or pyruvate is demonstrated on the reverse reaction. Citric acid cycle metabolites, specially malate and succinate, inhibit the direct reaction catalyzed by the “X” isozyme.These peculiar characteristics suggest a high degree of specialization for the principal testicular isozyme of lactate dehydrogenase.
Electrophoretic resolution of lactate dehydrogenase in mature testes from a variety of animals re... more Electrophoretic resolution of lactate dehydrogenase in mature testes from a variety of animals revealed one or more unusual isozymes in addition to the usual five forms. Dissociation of the enzyme and recombination of the polypeptide subunits led to the formation of new isozymes and to a redistribution of activity among those normally present, indicating that lactate dehydrogenase synthesis in postpubertal testis is controlled by more than two genes.
One or more electrophoretically unusual isozymes of LDH have been demonstrated in homogenates of ... more One or more electrophoretically unusual isozymes of LDH have been demonstrated in homogenates of mature testes from some species. Analyses of the isozymic composition of many other tissues, developing testes, and seminal fluid revealed that these unusual forms, or “band X” isozymes, are present only in postpubertal testes and are localized in the differentiating germ cells of the seminiferous tubules. Rates of reactivity with certain alpha-hydroxy acids and analogs of nicotinamide adenine dinucleotide differentiated some of the “band X” isozymes from the usual LDH isozymes. Results of dissociation and recombination studies on homogenates of human and rabbit testes indicated a similarity in structure between “band X” and the other isozymes.The ontogeny and characteristic distribution of the “band X” isozymes suggested that each fulfills a specific metabolic function. As yet the nature of this metabolic assignment has not been determined.
In order to evaluate the efficiency of inter-simple sequence repeat (ISSR) markers for Olea europ... more In order to evaluate the efficiency of inter-simple sequence repeat (ISSR) markers for Olea europaea L. varietal identification purposes, ten primers constituted by simple sequence repeats were tested against drupes and leaves from ten Italian O. europaea cultivars. Leaf DNA was initially used to assess optimal PCR conditions as well as to screen the effectiveness of the primers. Subsequently, DNA extraction from drupes, rich in PCR interfering substances such as phenolic compounds and lipids, was set up. An analysis of primer informativeness in the chosen set of cultivars was also carried out. By combining the amplification patterns from two primers, namely UBC-841 and UBC-808, that were the most polymorphic in terms of both polymorphic/amplified bands ratio and resolving power, it was possible to distinguish the drupes from all the examined cultivars.
Seventy nine microsatellite markers from hexaploid bread wheat (T. aestivum L.) were integrated ... more Seventy nine microsatellite markers from hexaploid bread wheat (T. aestivum L.) were integrated into a genetic linkage map of durum wheat (T. turgidum ssp. durum (Desf.) Huns.) created by RFLP segregation data from a population of 65 recombinant inbred lines. The results indicate a relatively even distribution of microsatellite loci and demonstrate that microsatellite markers from hexaploid wheat provide an excellent source of molecular markers for use in the genetics and breeding of durum wheat.
DNA analysis enables genome fingerprinting with consequent identification of different individual... more DNA analysis enables genome fingerprinting with consequent identification of different individuals. In the agro-food industry, this can have interesting applications for the identification of species and cultivars of both raw materials and processed food. In this investigation, the efficiency of DNA microsatellite analysis in identifying virgin olive oils from different cultivars was evaluated. Ten virgin oils were obtained in the laboratory from olives of 10 different cultivars and the DNA extracted from the cell residues, recovered by oil centrifugation, was used as a template with seven different primer pairs of microsatellite sequences. The electrophoretic patterns showed an adequate level of amplification and were identical to those obtained from leaves and drupes of the same cultivar. By analyzing all the patterns obtained, the smallest number of microsatellites able to distinguish the examined oils was established and an identification key for the different oils was developed.
Seed storage protein content of durum wheat (Triticum turgidum var. durum) has an important effec... more Seed storage protein content of durum wheat (Triticum turgidum var. durum) has an important effect on nutritional value and pasta-making characteristics. The objective of this study was to determine by association with genetic markers the number, chromosomal location, and magnitude of effect of quantitative trait loci (QTLs) controlling protein concentration in kernels. A set of 65 recombinant inbred lines (RIs) was developed by single seed descent from a cross between cultivated durum wheat cv. ‘Messapia’ (low protein content) and accession MG4343 of the wild tetraploid wheat var. dicoccoides (high protein content). This population was characterized for eight morphological, six storage protein, one isozyme and 124 RFLP loci. Field trials were conducted in one location in 1993 and two locations in 1994. QTLs were mapped by regression analysis on each marker locus for each location and for the average across environments. A total of six putative QTLs were located on chromosome arms 4BS, SAL, 6AS, 6BS and 7BS. The number and size of QTLs detected varied across environments. The marker with the highest r2 value per QTL in each environment and across environments was chosen for a multiple linear regression analysis, which explained 49.2- 56.4% of the phenotypic variation for protein content. Only some of the markers were found to be negatively associated with plant grain yield and/or seed weight in one or two of the environments.
SDS-sedimentation volume (SV) is a biochemical index widely used to evaluate flour quality in dur... more SDS-sedimentation volume (SV) is a biochemical index widely used to evaluate flour quality in durum and bread wheats. Significant association between SV and endosperm proteins (gliadin, high-molecular-weight- and low-molecular-weight-glutenin subunits) have been reported. Protein loci, however, account for only a portion of the total genetic variability. The objective of this study was to identify and locate quantitative trait loci (QTLs) associated with SV in a set of recombinant inbred (RI) lines, derived from a cross between the cv.‘Messapia’ of durum wheat and the accession MG4343 of the var. dicoccoides, and characterized for 259 genetic and molecular (RFLP) markers. Significant differences were detected for the quality index in the six environments examined, while the pattern of variability was that of a quantitative trait. Regression analysis of marker loci and sedimentation volume indicated, as expected, that chromosome 1B, on which are located the Gli-B 1/Glu-B 3 loci for some gliadin and glutenin subunits, is important for wheat quality. Two additional regions located on chromosomes 6AL and 7BS, and four regions on 1AL, 3AS, 3BL and 5AL, were shown to have single-factor effects on sedimentation volume at P < 0.001 and P < 0.01, respectively. Positive effects were contributed by both parents. A multiple linear regression model consisting of seven significant loci on different chromosomes explained 62–91% of the genotypic variation of the trait. The availability of linked markers to QTLs may facilitate the genetic dissection of quantitative traits and the early selection in wheat breeding programmes.
In order to evaluate the efficiency of inter-simple sequence repeat (ISSR) markers for Olea europ... more In order to evaluate the efficiency of inter-simple sequence repeat (ISSR) markers for Olea europaea L. varietal identification purposes, ten primers constituted by simple sequence repeats were tested against drupes and leaves from ten Italian O. europaea cultivars. Leaf DNA was initially used to assess optimal PCR conditions as well as to screen the effectiveness of the primers. Subsequently, DNA extraction from drupes, rich in PCR interfering substances such as phenolic compounds and lipids, was set up. An analysis of primer informativeness in the chosen set of cultivars was also carried out. By combining the amplification patterns from two primers, namely UBC-841 and UBC-808, that were the most polymorphic in terms of both polymorphic/amplified bands ratio and resolving power, it was possible to distinguish the drupes from all the examined cultivars.
Seventy nine microsatellite markers from hexaploid bread wheat (T. aestivum L.) were integrated ... more Seventy nine microsatellite markers from hexaploid bread wheat (T. aestivum L.) were integrated into a genetic linkage map of durum wheat (T. turgidum ssp. durum (Desf.) Huns.) created by RFLP segregation data from a population of 65 recombinant inbred lines. The results indicate a relatively even distribution of microsatellite loci and demonstrate that microsatellite markers from hexaploid wheat provide an excellent source of molecular markers for use in the genetics and breeding of durum wheat.
DNA analysis enables genome fingerprinting with consequent identification of different individual... more DNA analysis enables genome fingerprinting with consequent identification of different individuals. In the agro-food industry, this can have interesting applications for the identification of species and cultivars of both raw materials and processed food. In this investigation, the efficiency of DNA microsatellite analysis in identifying virgin olive oils from different cultivars was evaluated. Ten virgin oils were obtained in the laboratory from olives of 10 different cultivars and the DNA extracted from the cell residues, recovered by oil centrifugation, was used as a template with seven different primer pairs of microsatellite sequences. The electrophoretic patterns showed an adequate level of amplification and were identical to those obtained from leaves and drupes of the same cultivar. By analyzing all the patterns obtained, the smallest number of microsatellites able to distinguish the examined oils was established and an identification key for the different oils was developed.
Seed storage protein content of durum wheat (Triticum turgidum var. durum) has an important effec... more Seed storage protein content of durum wheat (Triticum turgidum var. durum) has an important effect on nutritional value and pasta-making characteristics. The objective of this study was to determine by association with genetic markers the number, chromosomal location, and magnitude of effect of quantitative trait loci (QTLs) controlling protein concentration in kernels. A set of 65 recombinant inbred lines (RIs) was developed by single seed descent from a cross between cultivated durum wheat cv. ‘Messapia’ (low protein content) and accession MG4343 of the wild tetraploid wheat var. dicoccoides (high protein content). This population was characterized for eight morphological, six storage protein, one isozyme and 124 RFLP loci. Field trials were conducted in one location in 1993 and two locations in 1994. QTLs were mapped by regression analysis on each marker locus for each location and for the average across environments. A total of six putative QTLs were located on chromosome arms 4BS, SAL, 6AS, 6BS and 7BS. The number and size of QTLs detected varied across environments. The marker with the highest r2 value per QTL in each environment and across environments was chosen for a multiple linear regression analysis, which explained 49.2- 56.4% of the phenotypic variation for protein content. Only some of the markers were found to be negatively associated with plant grain yield and/or seed weight in one or two of the environments.
SDS-sedimentation volume (SV) is a biochemical index widely used to evaluate flour quality in dur... more SDS-sedimentation volume (SV) is a biochemical index widely used to evaluate flour quality in durum and bread wheats. Significant association between SV and endosperm proteins (gliadin, high-molecular-weight- and low-molecular-weight-glutenin subunits) have been reported. Protein loci, however, account for only a portion of the total genetic variability. The objective of this study was to identify and locate quantitative trait loci (QTLs) associated with SV in a set of recombinant inbred (RI) lines, derived from a cross between the cv.‘Messapia’ of durum wheat and the accession MG4343 of the var. dicoccoides, and characterized for 259 genetic and molecular (RFLP) markers. Significant differences were detected for the quality index in the six environments examined, while the pattern of variability was that of a quantitative trait. Regression analysis of marker loci and sedimentation volume indicated, as expected, that chromosome 1B, on which are located the Gli-B 1/Glu-B 3 loci for some gliadin and glutenin subunits, is important for wheat quality. Two additional regions located on chromosomes 6AL and 7BS, and four regions on 1AL, 3AS, 3BL and 5AL, were shown to have single-factor effects on sedimentation volume at P < 0.001 and P < 0.01, respectively. Positive effects were contributed by both parents. A multiple linear regression model consisting of seven significant loci on different chromosomes explained 62–91% of the genotypic variation of the trait. The availability of linked markers to QTLs may facilitate the genetic dissection of quantitative traits and the early selection in wheat breeding programmes.
A genetic linkage map of tetraploid wheat [Triticum turgidum (L.) Thell.] was constructed using ... more A genetic linkage map of tetraploid wheat [Triticum turgidum (L.) Thell.] was constructed using segregation data from a population of 65 recombinant inbred lines (RILs) derived from a cross between the durum wheat cultivar Messapia and accession MG4343 of T. turgidum (L.) Thell. ssp dicoccoides (Korn.) Thell. A total of 259 loci were analysed, including 244 restriction fragment length polymorphisms (RFLPs), one PCR (polymerase chain reaction) marker (a sequence coding for a LMW (low-molecular-weight) glutenin subunit gene located at the Glu-B3 locus), seven biochemical (six seed-storage protein loci and one isozyme locus) and seven morphological markers. A total of 213 loci were mapped at a LOD≥3 on all 14 chromosomes of the A and B genomes. The total length of the map is 1352 cM and the average distance between adjacent markers is 6.3 cM. Forty six loci could not be mapped at a LOD≥3. A fraction (18.6%) of the markers deviated significantly from the expected Mendelian ratios; clusters of loci showing distorted segregation were found on chromosomes 1B, 3AL, 4AL, 6AL and 7AL. The durum wheat map was compared with the published maps of bread wheat using several common RFLP markers and general features are discussed. The markers detected the known structural rearrangements involving chromosomes 4A, 5A and 7B as well as the translocation between 2B-6B, but not the deletion on 2BS. This map provides a useful tool for analysing and breeding economically important quantitative traits and for marker-assisted selection, as well as for studies of genome organisation in small grain cereal species.
Carotenoids are essential components in all plants. Their accumulation in wheat seed determines t... more Carotenoids are essential components in all plants. Their accumulation in wheat seed determines the endosperm colour, which is an important quality trait in wheat. In this study, we report the isolation of BAC clones containing genes coding for three different enzymes of the carotenoid biosynthesis pathway: phytoene synthase (PSY), phytoene desaturase (PDS), and zeta-carotene desaturase (ZDS). Primers were designed on the basis of wheat ESTs similar to the sequences of these three genes in other species, and used to screen a BAC library from Triticum turgidum var. durum (2n = 28, genomes AABB). Eight, six, and nine 384-well plates containing at least one positive clone were found for PSY, PDS, and ZDS, respectively. BACs selected for each of these genes were then divided in two groups corresponding to the A and B genomes of tetraploid wheat, based on differences in the length of the PCR amplification products, conformation-sensitive gel electrophoresis (CSGE), or cleavage amplification polymorphisms. Positive clones were then assigned to chromosomes using a set of D genome substitution lines in T. turgidum var. durum &amp;amp;amp;amp;#39;Langdon&amp;amp;amp;amp;#39;. PSY clones were localized on chromosomes 5A and 5B, PDS on chromosomes 4A and 4B, and ZDS on chromosomes 2A and 2B. The strategies used for the PCR screening of large BAC libraries and for the differentiation of BAC clones from different genomes in a polyploid species are discussed.
Lactate dehydrogenase (LDH) isozyme 1 (B4), 5 (A4), and “X” (Testis or Sperm type) have been part... more Lactate dehydrogenase (LDH) isozyme 1 (B4), 5 (A4), and “X” (Testis or Sperm type) have been partially purified from mouse tissues.The following studies were carried out on the three isozymes: Km and optimum substrate concentration for pyruvate, α-oxo-butyrate, α-oxo-valerate, lactate, α-OH-butyrate, and α-OH-valerate, inhibition by substrate and product, effect of malate, N-(4-carboxy-2-hydroxyphenyl) maleimide, some citric acid cycle metabolites, urea, trypsin and pH.The mouse testicular LDH isozyme clearly differs from the common lactate dehydrogenases and from the tesficular isozymes from other species. It shows distinct sensitivity to inhibition by substrate or product whether the direct (pyruvate lactate) or reverse reactions are studied. There is no effect of increasing concentrations of pyruvate or lactate on the direct reaction, while a clear inhibition by lactate or pyruvate is demonstrated on the reverse reaction. Citric acid cycle metabolites, specially malate and succinate, inhibit the direct reaction catalyzed by the “X” isozyme.These peculiar characteristics suggest a high degree of specialization for the principal testicular isozyme of lactate dehydrogenase.
Electrophoretic resolution of lactate dehydrogenase in mature testes from a variety of animals re... more Electrophoretic resolution of lactate dehydrogenase in mature testes from a variety of animals revealed one or more unusual isozymes in addition to the usual five forms. Dissociation of the enzyme and recombination of the polypeptide subunits led to the formation of new isozymes and to a redistribution of activity among those normally present, indicating that lactate dehydrogenase synthesis in postpubertal testis is controlled by more than two genes.
One or more electrophoretically unusual isozymes of LDH have been demonstrated in homogenates of ... more One or more electrophoretically unusual isozymes of LDH have been demonstrated in homogenates of mature testes from some species. Analyses of the isozymic composition of many other tissues, developing testes, and seminal fluid revealed that these unusual forms, or “band X” isozymes, are present only in postpubertal testes and are localized in the differentiating germ cells of the seminiferous tubules. Rates of reactivity with certain alpha-hydroxy acids and analogs of nicotinamide adenine dinucleotide differentiated some of the “band X” isozymes from the usual LDH isozymes. Results of dissociation and recombination studies on homogenates of human and rabbit testes indicated a similarity in structure between “band X” and the other isozymes.The ontogeny and characteristic distribution of the “band X” isozymes suggested that each fulfills a specific metabolic function. As yet the nature of this metabolic assignment has not been determined.
In order to evaluate the efficiency of inter-simple sequence repeat (ISSR) markers for Olea europ... more In order to evaluate the efficiency of inter-simple sequence repeat (ISSR) markers for Olea europaea L. varietal identification purposes, ten primers constituted by simple sequence repeats were tested against drupes and leaves from ten Italian O. europaea cultivars. Leaf DNA was initially used to assess optimal PCR conditions as well as to screen the effectiveness of the primers. Subsequently, DNA extraction from drupes, rich in PCR interfering substances such as phenolic compounds and lipids, was set up. An analysis of primer informativeness in the chosen set of cultivars was also carried out. By combining the amplification patterns from two primers, namely UBC-841 and UBC-808, that were the most polymorphic in terms of both polymorphic/amplified bands ratio and resolving power, it was possible to distinguish the drupes from all the examined cultivars.
Seventy nine microsatellite markers from hexaploid bread wheat (T. aestivum L.) were integrated ... more Seventy nine microsatellite markers from hexaploid bread wheat (T. aestivum L.) were integrated into a genetic linkage map of durum wheat (T. turgidum ssp. durum (Desf.) Huns.) created by RFLP segregation data from a population of 65 recombinant inbred lines. The results indicate a relatively even distribution of microsatellite loci and demonstrate that microsatellite markers from hexaploid wheat provide an excellent source of molecular markers for use in the genetics and breeding of durum wheat.
DNA analysis enables genome fingerprinting with consequent identification of different individual... more DNA analysis enables genome fingerprinting with consequent identification of different individuals. In the agro-food industry, this can have interesting applications for the identification of species and cultivars of both raw materials and processed food. In this investigation, the efficiency of DNA microsatellite analysis in identifying virgin olive oils from different cultivars was evaluated. Ten virgin oils were obtained in the laboratory from olives of 10 different cultivars and the DNA extracted from the cell residues, recovered by oil centrifugation, was used as a template with seven different primer pairs of microsatellite sequences. The electrophoretic patterns showed an adequate level of amplification and were identical to those obtained from leaves and drupes of the same cultivar. By analyzing all the patterns obtained, the smallest number of microsatellites able to distinguish the examined oils was established and an identification key for the different oils was developed.
Seed storage protein content of durum wheat (Triticum turgidum var. durum) has an important effec... more Seed storage protein content of durum wheat (Triticum turgidum var. durum) has an important effect on nutritional value and pasta-making characteristics. The objective of this study was to determine by association with genetic markers the number, chromosomal location, and magnitude of effect of quantitative trait loci (QTLs) controlling protein concentration in kernels. A set of 65 recombinant inbred lines (RIs) was developed by single seed descent from a cross between cultivated durum wheat cv. ‘Messapia’ (low protein content) and accession MG4343 of the wild tetraploid wheat var. dicoccoides (high protein content). This population was characterized for eight morphological, six storage protein, one isozyme and 124 RFLP loci. Field trials were conducted in one location in 1993 and two locations in 1994. QTLs were mapped by regression analysis on each marker locus for each location and for the average across environments. A total of six putative QTLs were located on chromosome arms 4BS, SAL, 6AS, 6BS and 7BS. The number and size of QTLs detected varied across environments. The marker with the highest r2 value per QTL in each environment and across environments was chosen for a multiple linear regression analysis, which explained 49.2- 56.4% of the phenotypic variation for protein content. Only some of the markers were found to be negatively associated with plant grain yield and/or seed weight in one or two of the environments.
SDS-sedimentation volume (SV) is a biochemical index widely used to evaluate flour quality in dur... more SDS-sedimentation volume (SV) is a biochemical index widely used to evaluate flour quality in durum and bread wheats. Significant association between SV and endosperm proteins (gliadin, high-molecular-weight- and low-molecular-weight-glutenin subunits) have been reported. Protein loci, however, account for only a portion of the total genetic variability. The objective of this study was to identify and locate quantitative trait loci (QTLs) associated with SV in a set of recombinant inbred (RI) lines, derived from a cross between the cv.‘Messapia’ of durum wheat and the accession MG4343 of the var. dicoccoides, and characterized for 259 genetic and molecular (RFLP) markers. Significant differences were detected for the quality index in the six environments examined, while the pattern of variability was that of a quantitative trait. Regression analysis of marker loci and sedimentation volume indicated, as expected, that chromosome 1B, on which are located the Gli-B 1/Glu-B 3 loci for some gliadin and glutenin subunits, is important for wheat quality. Two additional regions located on chromosomes 6AL and 7BS, and four regions on 1AL, 3AS, 3BL and 5AL, were shown to have single-factor effects on sedimentation volume at P < 0.001 and P < 0.01, respectively. Positive effects were contributed by both parents. A multiple linear regression model consisting of seven significant loci on different chromosomes explained 62–91% of the genotypic variation of the trait. The availability of linked markers to QTLs may facilitate the genetic dissection of quantitative traits and the early selection in wheat breeding programmes.
In order to evaluate the efficiency of inter-simple sequence repeat (ISSR) markers for Olea europ... more In order to evaluate the efficiency of inter-simple sequence repeat (ISSR) markers for Olea europaea L. varietal identification purposes, ten primers constituted by simple sequence repeats were tested against drupes and leaves from ten Italian O. europaea cultivars. Leaf DNA was initially used to assess optimal PCR conditions as well as to screen the effectiveness of the primers. Subsequently, DNA extraction from drupes, rich in PCR interfering substances such as phenolic compounds and lipids, was set up. An analysis of primer informativeness in the chosen set of cultivars was also carried out. By combining the amplification patterns from two primers, namely UBC-841 and UBC-808, that were the most polymorphic in terms of both polymorphic/amplified bands ratio and resolving power, it was possible to distinguish the drupes from all the examined cultivars.
Seventy nine microsatellite markers from hexaploid bread wheat (T. aestivum L.) were integrated ... more Seventy nine microsatellite markers from hexaploid bread wheat (T. aestivum L.) were integrated into a genetic linkage map of durum wheat (T. turgidum ssp. durum (Desf.) Huns.) created by RFLP segregation data from a population of 65 recombinant inbred lines. The results indicate a relatively even distribution of microsatellite loci and demonstrate that microsatellite markers from hexaploid wheat provide an excellent source of molecular markers for use in the genetics and breeding of durum wheat.
DNA analysis enables genome fingerprinting with consequent identification of different individual... more DNA analysis enables genome fingerprinting with consequent identification of different individuals. In the agro-food industry, this can have interesting applications for the identification of species and cultivars of both raw materials and processed food. In this investigation, the efficiency of DNA microsatellite analysis in identifying virgin olive oils from different cultivars was evaluated. Ten virgin oils were obtained in the laboratory from olives of 10 different cultivars and the DNA extracted from the cell residues, recovered by oil centrifugation, was used as a template with seven different primer pairs of microsatellite sequences. The electrophoretic patterns showed an adequate level of amplification and were identical to those obtained from leaves and drupes of the same cultivar. By analyzing all the patterns obtained, the smallest number of microsatellites able to distinguish the examined oils was established and an identification key for the different oils was developed.
Seed storage protein content of durum wheat (Triticum turgidum var. durum) has an important effec... more Seed storage protein content of durum wheat (Triticum turgidum var. durum) has an important effect on nutritional value and pasta-making characteristics. The objective of this study was to determine by association with genetic markers the number, chromosomal location, and magnitude of effect of quantitative trait loci (QTLs) controlling protein concentration in kernels. A set of 65 recombinant inbred lines (RIs) was developed by single seed descent from a cross between cultivated durum wheat cv. ‘Messapia’ (low protein content) and accession MG4343 of the wild tetraploid wheat var. dicoccoides (high protein content). This population was characterized for eight morphological, six storage protein, one isozyme and 124 RFLP loci. Field trials were conducted in one location in 1993 and two locations in 1994. QTLs were mapped by regression analysis on each marker locus for each location and for the average across environments. A total of six putative QTLs were located on chromosome arms 4BS, SAL, 6AS, 6BS and 7BS. The number and size of QTLs detected varied across environments. The marker with the highest r2 value per QTL in each environment and across environments was chosen for a multiple linear regression analysis, which explained 49.2- 56.4% of the phenotypic variation for protein content. Only some of the markers were found to be negatively associated with plant grain yield and/or seed weight in one or two of the environments.
SDS-sedimentation volume (SV) is a biochemical index widely used to evaluate flour quality in dur... more SDS-sedimentation volume (SV) is a biochemical index widely used to evaluate flour quality in durum and bread wheats. Significant association between SV and endosperm proteins (gliadin, high-molecular-weight- and low-molecular-weight-glutenin subunits) have been reported. Protein loci, however, account for only a portion of the total genetic variability. The objective of this study was to identify and locate quantitative trait loci (QTLs) associated with SV in a set of recombinant inbred (RI) lines, derived from a cross between the cv.‘Messapia’ of durum wheat and the accession MG4343 of the var. dicoccoides, and characterized for 259 genetic and molecular (RFLP) markers. Significant differences were detected for the quality index in the six environments examined, while the pattern of variability was that of a quantitative trait. Regression analysis of marker loci and sedimentation volume indicated, as expected, that chromosome 1B, on which are located the Gli-B 1/Glu-B 3 loci for some gliadin and glutenin subunits, is important for wheat quality. Two additional regions located on chromosomes 6AL and 7BS, and four regions on 1AL, 3AS, 3BL and 5AL, were shown to have single-factor effects on sedimentation volume at P < 0.001 and P < 0.01, respectively. Positive effects were contributed by both parents. A multiple linear regression model consisting of seven significant loci on different chromosomes explained 62–91% of the genotypic variation of the trait. The availability of linked markers to QTLs may facilitate the genetic dissection of quantitative traits and the early selection in wheat breeding programmes.
A genetic linkage map of tetraploid wheat [Triticum turgidum (L.) Thell.] was constructed using ... more A genetic linkage map of tetraploid wheat [Triticum turgidum (L.) Thell.] was constructed using segregation data from a population of 65 recombinant inbred lines (RILs) derived from a cross between the durum wheat cultivar Messapia and accession MG4343 of T. turgidum (L.) Thell. ssp dicoccoides (Korn.) Thell. A total of 259 loci were analysed, including 244 restriction fragment length polymorphisms (RFLPs), one PCR (polymerase chain reaction) marker (a sequence coding for a LMW (low-molecular-weight) glutenin subunit gene located at the Glu-B3 locus), seven biochemical (six seed-storage protein loci and one isozyme locus) and seven morphological markers. A total of 213 loci were mapped at a LOD≥3 on all 14 chromosomes of the A and B genomes. The total length of the map is 1352 cM and the average distance between adjacent markers is 6.3 cM. Forty six loci could not be mapped at a LOD≥3. A fraction (18.6%) of the markers deviated significantly from the expected Mendelian ratios; clusters of loci showing distorted segregation were found on chromosomes 1B, 3AL, 4AL, 6AL and 7AL. The durum wheat map was compared with the published maps of bread wheat using several common RFLP markers and general features are discussed. The markers detected the known structural rearrangements involving chromosomes 4A, 5A and 7B as well as the translocation between 2B-6B, but not the deletion on 2BS. This map provides a useful tool for analysing and breeding economically important quantitative traits and for marker-assisted selection, as well as for studies of genome organisation in small grain cereal species.
Carotenoids are essential components in all plants. Their accumulation in wheat seed determines t... more Carotenoids are essential components in all plants. Their accumulation in wheat seed determines the endosperm colour, which is an important quality trait in wheat. In this study, we report the isolation of BAC clones containing genes coding for three different enzymes of the carotenoid biosynthesis pathway: phytoene synthase (PSY), phytoene desaturase (PDS), and zeta-carotene desaturase (ZDS). Primers were designed on the basis of wheat ESTs similar to the sequences of these three genes in other species, and used to screen a BAC library from Triticum turgidum var. durum (2n = 28, genomes AABB). Eight, six, and nine 384-well plates containing at least one positive clone were found for PSY, PDS, and ZDS, respectively. BACs selected for each of these genes were then divided in two groups corresponding to the A and B genomes of tetraploid wheat, based on differences in the length of the PCR amplification products, conformation-sensitive gel electrophoresis (CSGE), or cleavage amplification polymorphisms. Positive clones were then assigned to chromosomes using a set of D genome substitution lines in T. turgidum var. durum &amp;amp;amp;amp;#39;Langdon&amp;amp;amp;amp;#39;. PSY clones were localized on chromosomes 5A and 5B, PDS on chromosomes 4A and 4B, and ZDS on chromosomes 2A and 2B. The strategies used for the PCR screening of large BAC libraries and for the differentiation of BAC clones from different genomes in a polyploid species are discussed.
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Papers by Antonio Blanco