Svevo and bread wheat cv. Perzivan carrying a translocated segment of the short arm of chromosome... more Svevo and bread wheat cv. Perzivan carrying a translocated segment of the short arm of chromosome 1D containing the Gli-D1/Glu-D3 loci on the short arm of chromosome 1A. Lines expressing both the 5+10 subunits and Gli-D1/Glu-D3 proteins were isola... ...
Genes encoding D-genome related gliadins and glutenin subunits have been transferred to durum whe... more Genes encoding D-genome related gliadins and glutenin subunits have been transferred to durum wheat through chromosome engineering. In particular, segments containing genes corresponding to the pairs of high-molecular-weight glutenin subunits (HMW-GS) 5+10 or 2+12, normally present at the Glu-D1 locus in bread wheat, have been introgressed into chromosome 1A of different durum wheat cultivars, replacing the null allele present at the Glu-A1 locus. Using the same approach or the bread wheat cultivar Perzivan, carrying a translocation involving the short arm of chromosomes 1A and 1D, the two alleles present at Gli-D1/Glu-D3 loci in most bread wheat cultivars, encoding gliadin and low molecular weight glutenin subunits (LMW-GS), have also been introduced into durum wheat
Hordeum chilense Roem. et Schult. is a native South American diploid wild barley included in the ... more Hordeum chilense Roem. et Schult. is a native South American diploid wild barley included in the section Anisolepis Nevski. H. chilense occurs exclusively in Chile and Argentina and has been used in the synthesis of a new amphiploid named tritordeum (×Tritordeum Ascherson et Graebner). The HMW glutenin subunits of H. chilense have a great influence on gluten strength of tritordeum.
Electrophoretical analyses of the gliadin fraction extracted from seeds of the intervarietal subs... more Electrophoretical analyses of the gliadin fraction extracted from seeds of the intervarietal substitution lines of T. aestivum ssp. spelta in the T. aestivum ssp. vulgare cv 'Chinese Spring' for the homoeologous groups 1 and 6 and substitution lines of 6D chromosome of 'Chinese Spring' in the durum wheat cv 'Langdon' allowed the identification of seeds without gliadin proteins controlled by genes on chromosome 6A and 6B. A gliadin component of 'Chinese Spring', not previously assigned to any specific chromosome, is controlled by chromosome 6D in the 6D (6A) and 6D (6B) disomic substitution lines of 'Langdon'. Additional genes controlling the synthesis of this component may be present on other chromosomes, very likely 6A and 6B, since the analysis of the 'Chinese Spring' compensating nullisomic-tetrasomics involving the 6D chromosome does not show the loss of this component or any apparent change in staining intensity. Chromosomal location data and two-dimensional gliadin maps reveal close homologies between the two hexaploid wheats, 'Chinese Spring' (T. aestivum ssp. vulgare) and T. aestivum ssp. spelta, belonging to different subspecies in the hexaploid group of genomic formula AABBDD. The comparison of gliadin electrophoretic patterns aiding in the identification of evolutionary pathways in wheat is stressed.
Recently, electrophoretic analyses of waxy proteins in several hexaploid and tetraploid wheat acc... more Recently, electrophoretic analyses of waxy proteins in several hexaploid and tetraploid wheat accessions from worldwide collections have permitted the identification of new variants at the waxy loci, including allelic forms with different mobilities and partial null types. In this paper, the molecular characterization of mutated waxy loci in four bread wheat cultivars (two lacking the Wx-B1 and two lacking the Wx-D1 protein, respectively) and in four durum wheat cultivars (one lacking Wx-A1 and the remainder with Wx-B1 proteins showing different electrophoretic mobilities) was conducted by means of PCR, Southern and DNA sequence analyses. Three primer pairs were developed that identified six of the above-mentioned mutations and allowed their molecular description, providing a useful tool for further germplasm screening or marker assisted progeny selection in breeding programs involving the newly identified material. We have found that a complete gene deletion is responsible for a null allele at the Wx-B1 locus in one bread wheat line, whereas sequencing of the corresponding fragments showed a 724 bp deletion in the Wx-D1 locus in one line of bread wheat and an insertion of 89 bp in the Wx-A1 locus in one line of durum wheat, respectively. In addition, nucleotide substitutions and various insertions/ deletions ranging from 3 to 30 bp were detected in the PCR fragments of one durum wheat line with a Wx-B1 protein with a different electrophoretic mobility. A fourth primer set, specific for this mutation, was consequently derived.
Hemocyanin is a copper-containing respiratory protein that is widespread within the arthropod phy... more Hemocyanin is a copper-containing respiratory protein that is widespread within the arthropod phylum. Among the Crustacea, hemocyanins are apparently restricted to the Malacostraca. While well-studied in Decapoda, no hemocyanin sequence has been known from the 'lower' Malacostraca. The hemocyanin of the amphipod Gammarus roeseli is a hexamer that consists of at least five distinct subunits. The complete cDNA sequence of one subunit and a tentative partial sequence of another subunit have been determined. The complete G. roeseli hemocyanin subunit comprises 2,150 bp, which translates in a protein of 672 amino acids with a molecular mass of 76.3 kDa. Phylogenetic analyses show that, in contrast to previous assumptions, the amphipod hemocyanins do not belong to the alpha-type of crustacean hemocyanin subunits. Rather, amphipod hemocyanins split from the clade leading to alpha and gamma-subunits most likely at the time of separation of peracarid and eucarid Crustacea about 300 million years ago. Molecular clock analyses further suggest that the divergence of beta-type subunits and other crustacean hemocyanins occurred around 315 million years ago (MYA) in the malacostracan stemline, while alpha- and gamma-type subunits separated 258 MYA, and pseudohemocyanins and gamma-subunits 210 million years ago.
A large collection of accessions of the wild wheat progenitor Triticum tauschii, the donor of the... more A large collection of accessions of the wild wheat progenitor Triticum tauschii, the donor of the D genome of Triticum aestivum, was evaluated for the variability of high molecular weight (M r ) glutenin subunits by electrophoretic and chromatographic methods. A large range of allelic variation at the Glu-D t 1 locus was found in this collection and some novel subunits were observed in both x-and ytype glutenin subunits, including x-or y-type null forms. A few accessions showed three bands in the high M r glutenin subunit region. However, only two subunits were observed when monomeric proteins were removed before SDS-PAGE analysis of polymeric proteins. The presence of monomeric proteins in this region is discussed. Characterisation of these subunits was also carried out by reversed phase-high performance liquid chromatography (RP-HPLC). Very different surface hydrophobicities were observed between x-and y-type subunits and in some cases it was possible to identify glutenin subunits with the same apparent molecular weight but different surface hydrophobicity. Differences in elution times that were detected when the same subunit was either reduced or reduced and alkylated were related to the number of cysteine residues present in each glutenin subunit. The new Glu-D t 1 glutenin subunits have the potential to enhance the genetic variability available for improving the quality of bread wheat (T. aestivum).
Svevo and bread wheat cv. Perzivan carrying a translocated segment of the short arm of chromosome... more Svevo and bread wheat cv. Perzivan carrying a translocated segment of the short arm of chromosome 1D containing the Gli-D1/Glu-D3 loci on the short arm of chromosome 1A. Lines expressing both the 5+10 subunits and Gli-D1/Glu-D3 proteins were isola... ...
Genes encoding D-genome related gliadins and glutenin subunits have been transferred to durum whe... more Genes encoding D-genome related gliadins and glutenin subunits have been transferred to durum wheat through chromosome engineering. In particular, segments containing genes corresponding to the pairs of high-molecular-weight glutenin subunits (HMW-GS) 5+10 or 2+12, normally present at the Glu-D1 locus in bread wheat, have been introgressed into chromosome 1A of different durum wheat cultivars, replacing the null allele present at the Glu-A1 locus. Using the same approach or the bread wheat cultivar Perzivan, carrying a translocation involving the short arm of chromosomes 1A and 1D, the two alleles present at Gli-D1/Glu-D3 loci in most bread wheat cultivars, encoding gliadin and low molecular weight glutenin subunits (LMW-GS), have also been introduced into durum wheat
Hordeum chilense Roem. et Schult. is a native South American diploid wild barley included in the ... more Hordeum chilense Roem. et Schult. is a native South American diploid wild barley included in the section Anisolepis Nevski. H. chilense occurs exclusively in Chile and Argentina and has been used in the synthesis of a new amphiploid named tritordeum (×Tritordeum Ascherson et Graebner). The HMW glutenin subunits of H. chilense have a great influence on gluten strength of tritordeum.
Electrophoretical analyses of the gliadin fraction extracted from seeds of the intervarietal subs... more Electrophoretical analyses of the gliadin fraction extracted from seeds of the intervarietal substitution lines of T. aestivum ssp. spelta in the T. aestivum ssp. vulgare cv 'Chinese Spring' for the homoeologous groups 1 and 6 and substitution lines of 6D chromosome of 'Chinese Spring' in the durum wheat cv 'Langdon' allowed the identification of seeds without gliadin proteins controlled by genes on chromosome 6A and 6B. A gliadin component of 'Chinese Spring', not previously assigned to any specific chromosome, is controlled by chromosome 6D in the 6D (6A) and 6D (6B) disomic substitution lines of 'Langdon'. Additional genes controlling the synthesis of this component may be present on other chromosomes, very likely 6A and 6B, since the analysis of the 'Chinese Spring' compensating nullisomic-tetrasomics involving the 6D chromosome does not show the loss of this component or any apparent change in staining intensity. Chromosomal location data and two-dimensional gliadin maps reveal close homologies between the two hexaploid wheats, 'Chinese Spring' (T. aestivum ssp. vulgare) and T. aestivum ssp. spelta, belonging to different subspecies in the hexaploid group of genomic formula AABBDD. The comparison of gliadin electrophoretic patterns aiding in the identification of evolutionary pathways in wheat is stressed.
Recently, electrophoretic analyses of waxy proteins in several hexaploid and tetraploid wheat acc... more Recently, electrophoretic analyses of waxy proteins in several hexaploid and tetraploid wheat accessions from worldwide collections have permitted the identification of new variants at the waxy loci, including allelic forms with different mobilities and partial null types. In this paper, the molecular characterization of mutated waxy loci in four bread wheat cultivars (two lacking the Wx-B1 and two lacking the Wx-D1 protein, respectively) and in four durum wheat cultivars (one lacking Wx-A1 and the remainder with Wx-B1 proteins showing different electrophoretic mobilities) was conducted by means of PCR, Southern and DNA sequence analyses. Three primer pairs were developed that identified six of the above-mentioned mutations and allowed their molecular description, providing a useful tool for further germplasm screening or marker assisted progeny selection in breeding programs involving the newly identified material. We have found that a complete gene deletion is responsible for a null allele at the Wx-B1 locus in one bread wheat line, whereas sequencing of the corresponding fragments showed a 724 bp deletion in the Wx-D1 locus in one line of bread wheat and an insertion of 89 bp in the Wx-A1 locus in one line of durum wheat, respectively. In addition, nucleotide substitutions and various insertions/ deletions ranging from 3 to 30 bp were detected in the PCR fragments of one durum wheat line with a Wx-B1 protein with a different electrophoretic mobility. A fourth primer set, specific for this mutation, was consequently derived.
Hemocyanin is a copper-containing respiratory protein that is widespread within the arthropod phy... more Hemocyanin is a copper-containing respiratory protein that is widespread within the arthropod phylum. Among the Crustacea, hemocyanins are apparently restricted to the Malacostraca. While well-studied in Decapoda, no hemocyanin sequence has been known from the 'lower' Malacostraca. The hemocyanin of the amphipod Gammarus roeseli is a hexamer that consists of at least five distinct subunits. The complete cDNA sequence of one subunit and a tentative partial sequence of another subunit have been determined. The complete G. roeseli hemocyanin subunit comprises 2,150 bp, which translates in a protein of 672 amino acids with a molecular mass of 76.3 kDa. Phylogenetic analyses show that, in contrast to previous assumptions, the amphipod hemocyanins do not belong to the alpha-type of crustacean hemocyanin subunits. Rather, amphipod hemocyanins split from the clade leading to alpha and gamma-subunits most likely at the time of separation of peracarid and eucarid Crustacea about 300 million years ago. Molecular clock analyses further suggest that the divergence of beta-type subunits and other crustacean hemocyanins occurred around 315 million years ago (MYA) in the malacostracan stemline, while alpha- and gamma-type subunits separated 258 MYA, and pseudohemocyanins and gamma-subunits 210 million years ago.
A large collection of accessions of the wild wheat progenitor Triticum tauschii, the donor of the... more A large collection of accessions of the wild wheat progenitor Triticum tauschii, the donor of the D genome of Triticum aestivum, was evaluated for the variability of high molecular weight (M r ) glutenin subunits by electrophoretic and chromatographic methods. A large range of allelic variation at the Glu-D t 1 locus was found in this collection and some novel subunits were observed in both x-and ytype glutenin subunits, including x-or y-type null forms. A few accessions showed three bands in the high M r glutenin subunit region. However, only two subunits were observed when monomeric proteins were removed before SDS-PAGE analysis of polymeric proteins. The presence of monomeric proteins in this region is discussed. Characterisation of these subunits was also carried out by reversed phase-high performance liquid chromatography (RP-HPLC). Very different surface hydrophobicities were observed between x-and y-type subunits and in some cases it was possible to identify glutenin subunits with the same apparent molecular weight but different surface hydrophobicity. Differences in elution times that were detected when the same subunit was either reduced or reduced and alkylated were related to the number of cysteine residues present in each glutenin subunit. The new Glu-D t 1 glutenin subunits have the potential to enhance the genetic variability available for improving the quality of bread wheat (T. aestivum).
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Papers by B. Margiotta