Effect of allelic variation at the Glu-3/Gli-1 loci on breadmaking quality parameters in hexaploid wheat (Triticum aestivum L.)

Low molecular weight glutenin subunits (LMW-GS) encoded by the Glu-3 loci are known to contribute to wheat breadmaking quality. However, the specific effect of individual Glu-3 alleles is not well understood due to their complex protein banding patterns in SDS-PAGE and tight linkage with gliadins at the Gli-1 locus. Using DNA markers and a backcross program we developed a set of nine near isogenic lines (NILs) including different Glu-A3/GliA-1 or Glu-B3/Gli-B1 alleles in the genetic background of the Argentine variety ProINTA Imperial. The nine NILs and the control were evaluated in three different field trials in Argentina. Significant genotype-by-environment interactions were detected for most quality parameters indicating that the effects of the Glu-3/Gli-1 alleles are modulated by environmental differences. None of the NILs showed differences in total flour protein content, but relative changes in the abundance of particular classes of proteins cannot be ruled out. On average, the Glu-A3f, Glu-B3b, Glu-B3g and Glu-B3i(Man) alleles were associated with the highest values in gluten strength-related parameters, while Glu-A3e, Glu-B3a and Glu-B3i(Chu) were consistently associated with weak gluten and low quality values. The value of different Glu3/Gli-1 allele combinations to improve breadmaking quality is discussed

The upgrade of base orcadas magnetic observatory

In January 2012 new absolute magnetometers, fluxgate variometers and recording hardware to monitor and record changes in the Earth’s magnetic field have been installed at Base Orcadas Observatory, in a collaborative project between the Argentine National Weather Service (SMN), the British Geological Survey (BGS) in Edinburgh and the Institut Royal Météorologique de Belgique, Dourbes as part of the INTERMAGNET Digital Geomagnetic Observatory (INDIGO) program. This observatory is located on the Argentine Antarctic Base on the South Orkney Islands (Orcadas del Sur), with the new equipment replacing existing photographic recording equipment which was damaged by an earthquake in 2003. The equipment is designed to meet INTERMAGNET standards for data quality providing a one-minute data set which will be corrected to absolute through a program of absolute observations. The original magnetic observatory at Base Orcadas (the oldest in Antarctica) was installed by the Scottish National Antarctic Expedition in (SNAE) 1902-04 and recordings of variations in the Earth’s magnetic field have continued since that time at this remote location

Biochemical and molecular characterisation of Glu-1 loci in Argentinean wheat cultivars.

The high molecular weight glutenin subunit (HMW-GS) composition of a collection of 107 Argentinean bread wheat cultivars was analysed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Allelic variation at the Glu-1 loci was identified and its frequency calculated. Eleven alleles were detected, three encoded at the Glu-A1 locus, six at the Glu-B1 locus and two at the Glu-D1 locus. A low frequency of the null allele at the Glu-A1 locus and a high frequency of subunits 5+10 at the Glu-D1 locus were observed. Reversed phase-high performance liquid chromatography (RP-HPLC) analysis was used to further characterise HMW-GS. Two different types of Bx subunit 8 (named subunits 8 and 8*) were detected, the latter having shorter elution time. Subunit 8* was not identifiable by SDS-PAGE. According to quantification by RP-HPLC analysis, two groups of subunit 7 were observed. One group, with a relatively high proportion of subunit 7 (approximately 39% of the total amount of HMW-GS) appeared in cultivars with allele 7+8* at the Glu-B1 locus; a second group of subunit 7 (around 24% of the total amount of HMW-GS), was found in alleles 7+8, 7+8* and 7+9. Restriction fragment length polymorphisms (RFLP) analyses of HMW-GS genes were also carried out after digestion of genomic DNA with HindIII and TaqI restriction enzymes. The relationship between DNA fragment size and glutenin subunits, as estimated by electrophoretic mobility in SDS-PAGE, was also examined. The restriction enzyme TaqI demonstrated to be a useful tool to detect homozygous plants in selection programs against the Glu-A1 null allele

Effect of Triticum monococcum glutenin loci on cookie making quality and on predictive tests for bread making quality

The effects of Triticum monococcum glutenin loci on cookie making quality and predictive tests for bread making quality were evaluated in recombinant substitution lines (RSLs) between chromosome 1A from T. monococcum and chromosome 1A from Chinese Spring. All four combinations of high molecular weight (HM -GS) and low molecular weight glutenin alleles (LM -GS) were studied in a factorial design to evaluate their interactions. Grain protein content was used as a covariable to evaluate the effect of these loci independently of the variation in protein content among lines. No significant interactions were detected indicating an additive effect. RSLs carrying the HM -GS from T. monococcum showed a 13.6% increase in SDS sedimentation volume (p=0.004) and a significant reduction in cookie diameter (-5.2%, p=0.02), and cookie quality (-6.8%, p=0.02). RSLs carrying the LM -GS from T. monococcum showed a significant decrease in the proportion of polymeric protein (-2.8%, p<0.0001), SDS sedimentation volume (-8.1%, p=0.03) and gluten strength (-16.5%, p=0.01), and a significant increase in cookie quality (5.9%, p=0.05). The T. monococcum LM -GS allele has potential value to be used in soft wheat breeding programs. These results suggest that diploid T. monococcum could be a valuable source for new allelic variation for storage proteins loci and new quality characteristics. © 2002 Elsevier Science Ltd. m r r r r

Effect of Triticum monococcum glutenin loci on cookie making quality and on predictive tests for bread making quality

The effects of Triticum monococcum glutenin loci on cookie making quality and predictive tests for bread making quality were evaluated in recombinant substitution lines (RSLs) between chromosome 1Am from T. monococcum and chromosome 1A from Chinese Spring. All four combinations of high molecular weight (HMr-GS) and low molecular weight glutenin alleles (LMr-GS) were studied in a factorial design to evaluate their interactions. Grain protein content was used as a covariable to evaluate the effect of these loci independently of the variation in protein content among lines. No significant interactions were detected indicating an additive effect. RSLs carrying the HMr-GS from T. monococcum showed a 13.6% increase in SDS sedimentation volume (p=0.004) and a significant reduction in cookie diameter (-5.2%, p=0.02), and cookie quality (-6.8%, p=0.02). RSLs carrying the LMr-GS from T. monococcum showed a significant decrease in the proportion of polymeric protein (-2.8%, p<0.0001), SDS sedimentation volume (-8.1%, p=0.03) and gluten strength (-16.5%, p=0.01), and a significant increase in cookie quality (5.9%, p=0.05). The T. monococcum LMr-GS allele has potential value to be used in soft wheat breeding programs. These results suggest that diploid T. monococcum could be a valuable source for new allelic variation for storage proteins loci and new quality characteristics. © 2002 Elsevier Science Ltd

Allelic variations in high and low molecular weight glutenins at the Glu-Dt locus of Aegilops tauschii as a potential source for improving bread wheat quality

Aegilops tauschii, the donor of the D genome of hexaploid wheat, is accepted as a major contributor of disease resistance and bread-making quality attributes in cultivated wheat. High molecular weight (HMW) glutenins have a significant effect on the bread-making qualities of cultivated wheat. A large range of allelic variation in 424 Ae. tauschii accessions at the Glu-D1t locus for both x- and y-type glutenin subunits as well as at Glu-D3t was observed with SDS-PAGE using the total endosperm protein fraction. Only 4 accessions revealed more than 2 bands on SDS-PAGE. Seventeen new allelic combinations of both x- and y-type glutenin subunits at GluD-1t and 30 new allelic profiles at Glu-D3 were detected. These combinations comprise some lines with x- or y-type null forms. RP-HPLC analysis of accession Aus 18882, which showed 5 bands when the total endosperm protein fraction was resolved on SDS-PAGE, revealed 2 x-types and 1 y-type subunit banding pattern. RP-HPLC of the gliadin fraction exhibited an omega gliadin-like subunit. SDS-PAGE processing of the gliadin-free fraction of the same accession still exhibited the gliadin-like protein. An N-terminal protein sequence of the first 7 amino acids of the slowest moving novel x- type band of accession Aus18882 indicated its uniqueness, as no entries were found to contain this internal sequence. Demonstration of novel allelic combinations at Glu-D1 and Glu-D3 loci implies the potential for exploiting Ae. tauschii to increase the genetic variability of hexaploid wheat, particularly for bread-making qualities