M. A. Martín

Molecular characterization and diversity of the Pina and Pinb genes in cultivated and wild diploid wheat

Grain hardness is one of the most important characteristics of wheat quality. Soft endosperm is associated with the presence of two proteins in the wild form, puroindoline a and b. The puroindoline genes and their derived proteins are present in the putative wheat diploid ancestors which are thought to be the donors of the A, B and D genomes in common and durum wheat. In this study, we investigated the variability of grain hardness in einkorn, along with the nucleotide diversity of Pina and Pinb genes in a collection of einkorn wheat and T. urartu, in addition to studying the neutrality and linkage disequilibrium of these genes. Various alleles were detected for Pina and Pinb genes including three novel alleles for the Pinb locus: Pinb-Am1i, Pinb-Am1j and Pinb-Am1k. Some differences were found in grain hardness between the different genotypes. The neutrality test showed a different pattern of variation between the two Pin genes. The genetic analysis of a diploid wheat collection has demonstrated that these species are a potential source of novel puroindoline variants. Our data suggest that, although further studies must be carried out, these variants could be used to expand the range of grain texture in durum and common wheat, which would permit the development of new materials adapted to novel uses in the baking and pasta industry.

Genetic diversity of Spanish fir (Abies pinsapo Boiss.) populations by means of megagametophyte storage proteins

Abstract• The Spanish fir (Abies pinsapo Boiss.) is a conifer endemic to southern Spain and belongs to a Mediterranean basin group of firs considered to be relict. Megagametophyte storage proteins are a useful tool for the evaluation of genetic variability due to the haploid nature of megagametophytes in conifers.• In this paper, we report for the first time, the usefulness of megagametophyte storage proteins marker in A. pinsapo as a first investigation of the level of genetic diversity conserved in the extant stands of this relict conifer. For this, four populations were analysed from the three areas in which the species is still found. A total of thirty trees and ten megagametophytes per tree were analysed. In addition, 191 megagametophytes from two trees were assessed to identify polymorphic bands and to confirm Mendelian inheritance 1:1.• Albumins have proved to be a good marker to assess the genetic variability in this species, due to their high level of variation. Fourteen polymorphic bands adjusted to the expected 1:1 segregation ratio, two cases of allelism and eight of linkage were detected.• The genetic diversity study showed that, in the four populations, approximately half of the genetic diversity was among trees and the other half among seeds of each tree. Differentiation between populations was less than 6.0%. Results from this study could be useful for determining appropriate conservation management strategies for this endangered species.

Polymorphisms at the Gli-Au1 and Gli-Au2 loci in wild diploid wheat (Triticum urartu)

Triticum urartu is a wild diploid wheat that has been identified as the donor of the A genome in polyploid wheats. The gliadins of this species were analysed by acid-PAGE in accessions from Armenia, Iran, Iraq, Lebanon, former-Soviet Union and Turkey. Up to twenty-six different alleles for each locus (Gli-Au1 and Gli-Au2) implicated in the synthesis of these proteins, were found. The genetic diversity was high, although a great part of this diversity is in danger of erosion given that the distribution of the combinations is not random. Consequently, loss of these accessions could mean loss of the allelic variants. These results provide new basic knowledge regarding the genetic variability of the seed storage proteins synthesised by the Au genome, as well as their potential to obtain novel germplasm for the improvement of wheat quality in breeding programmes.

Genetic diversity for seed storage proteins in Lebanon and Turkey populations of wild diploid wheat (Triticum urartu Thum. ex Gandil.)

Triticum urartu is a wild diploid wheat identified as donor of the A genome in the durum and bread wheats. This species has its natural distribution zone in the Fertile Crescent. Nine populations from this zone (five Lebanese and four Turkish) were analysed for the variation in the loci coding of endosperm storage proteins: glutenins (Glu-Au1 and Glu-Au3) and gliadins (Gli-Au1 and Gli-Au2). Up to 10 alleles for the Glu-Au1 locus, 16 for the Glu-Au3 locus, 15 for the Gli-Au1 locus and 18 for the Gli-Au2 locus were found. The Turkish populations showed greater diversity than the Lebanese populations, distributing mainly within populations, whereas the inverse process takes place for the Lebanese populations. The values of the genetic diversity indicated that, although these materials showed high level of variability, exist a real risk of genetic erosion.

Primeros resultados en el desarrollo de un marcador genético basado en las proteínas de reserva en dos especies del género Nothofagus

El genero Nothofagus (Nothofagaceae) comprende 12 especies y algunos hibridos entre las mismas. Algunas de estas especies se encuentran seriamente amenazadas, presentando una distribucion reducida y una gran erosion genetica. En este estudio fue desarrollado un marcador molecular basado en las proteinas de reserva de la semilla de especies del genero Nothofagus. Para ello se tomaron muestras de semilla de dos especies del genero, N. alessandrii y N. glauca. De las diferentes fracciones de proteinas de la semilla (albuminas, globulinas, prolaminas y glutelinas), las glutelinas mostraron los mejores resultados al presentar bandas mas conspicuas. Hasta 39 bandas fueron detectadas entre las dos especies, 22 en N. alessandrii (14 de ellas polimorficas) y 26 en N. glauca (21 polimorficas), siendo siete de ellas comunes a ambas especies. Se encontro una clara diferencia entre los perfiles proteicos de ambas especies, detectandose mayor diversidad genetica en N. glauca que en N. alessandrii. Aunque estos resultados son preliminares, sugieren que este marcador podria ser util para la evaluacion de la diversidad genetica en especies del genero Nothofagus.