Authors:Khaled Masmoudi, Ahmed Rebai, and Radhouane Ellouz
Bread wheat (
L.) is an economically and nutritionally important cereal crop in the Mediterranean region. Characterization of wheat germplasm by means of DNA fingerprinting techniques provides a tool to assess genetic diversity and to identify varieties. In this study, six Tunisian bread wheat cultivars were characterized by AFLP and SSR markers. Five AFLP primer pairs showed clear different patterns and seems to be the most suitable for analysis of the bread wheat varieties. Three SSR primers were polymorphic with more than two alleles. The pairwise genetic similarities (GS) based on these molecular markers were calculated and used to construct a dendrogram that allowed the discrimination of the six cultivars. The GS among the six varieties ranged from 0.79 to 0.36. The six varieties used in this work clustered into four groups using either AFLP or SSR markers. A high GS was found between Tebecca and Vaga Varieties which have a similar pedigree.
Authors:E. Nagy, G. Gyulai, Z. Szabó, Z. Hegyi, and L. C. Marton
Studies involving morphological description with both dominant (RAPD) and codominant (SSR, isoenzyme) molecular markers were made on 28 maize inbred lines of known genetic background with a final aim of prediction of heterosis. The genetic distance and degree of relationship between the lines was determined using cluster analysis. Only a very limited extent of allele polymorphism could be detected in isoenzyme analyses as the 28 lines formed only 16 gel electrophoretic groups, indicating that certain lines had identical isoenzyme patterns. On the basis of RAPD and gene-specific microsatellite (SSR) markers, however, all the lines could be distinguished from each other. When the lines were grouped according to genetic background it was found that although the individual marker systems only partially reflected the actual relationships between the lines, a joint processing of the data, supplemented with morphological data, revealed a close correlation between the groups formed on the dendrogram and the genetic background.
Aegiolops kotschyi cytoplasmic male sterile system often results in part of haploid plants in wheat (Triticum aestivum L.). To elucidate the origin of haploid, 235 wheat microsatellite (SSR) primers were randomly selected and screened for polymorphism between haploid (2n = 3x = 21 ABD) and its parents, male-sterile line YM21 (2n = 6x = 42 AABBDD) and male fertile restorer YM2 (2n = 6x = 42 AABBDD). About 200 SSR markers yielded clear bands from denatured PAGE, of which 180 markers have identifiable amplification patterns, and 20 markers (around 8%) resulted in different amplification products between the haploid and the restorer, YM2. There were no SSR markers that were found to be distinguishable between the haploid and the male sterile line YM21. In addition, different distribution of HMW-GS between endosperm and seedlings from the same seeds further confirmed that the haploid genomes were inherited from the maternal parent. After haploidization, 1.7% and 0.91% of total sites were up- and down-regulated exceeding twofold in the shoot and the root of haploid, respectively, and most of the differentially expressed loci were up/down-regulated about twofold. Out of the sensitive loci in haploid, 94 loci in the shoot, 72 loci in the root can be classified into three functional subdivisions: biological process, cellular component and molecular function, respectively.
It is well established that the ingestion of cereal prolamins, such as gluten, causes the characteristic symptoms of celiac disease (CD) in people predisposed to it. DNA-based PCR method provides new ways to detect gluten in processed foodstuffs, such as bread. The aim of this work was to adapt a new primer pair combination and to initiate a carefully elaborated PCR methodology to experiment with DNA-based analysis. At first, the purity of cleaned DNA was verified using B49317 and A49855 chloroplast DNA primer pair. Then TR01/2 wheat specific PCR primer pair was used for checking the origin of the DNA, and P1/2 microsatellite (SSR) adapted primer pair for detecting allergen (gluten) specific residues. Method optimisation was achieved with cereal flour samples, then bread and dry pasta products from wheat were used, which were analysed as heat-treated samples with three primer pairs. The gluten specific primer pair was tested on cross-reactive cereals such as rye, barley, triticale and on some questionable cereals, such as oat, and pseudo-cereals, e.g. buck wheat and amaranth.
The use of genetic markers allows the study of polymorphism and genetic distances between maize lines in greater depth than can be achieved on the basis of phenotype and DUS traits. The analysis of polymorphism between 46 maize inbred lines with known genetic background and the classification of these lines in related groups was carried out by means of morphological description, isoenzyme analysis, RAPD analysis, and identification using gene-linked microsatellite (SSR) markers. The genetic distance or degree of relationship between the lines was determined using cluster analysis. Only a very limited extent of allele polymorphism could be detected in isoenzyme analyses; the 46 lines formed only 18 gel electrophoresis groups. Nevertheless, on the basis of RAPD and SSR markers, all the lines could be distinguished from each other. This was reflected by the PIC (polymorphism index content) values, which ranged from 0.04 to 0.55 (mean 0.27) for the various enzyme loci, while far higher values were obtained for RAPD and SSR markers (0.20–0.91, mean 0.61, and 0.54–0.90, mean 0.73, respectively). Due to the large number of lines, two lines, derived from each other or from common parents, were chosen from each related group as the basis for grouping the lines according to genetic background. It was found that, while the individual marker systems only partially reflected the actual relationships between the lines, a joint processing of the genetic markers, supplemented with morphological data, revealed a close correlation between the groups formed on the dendrogram and the genetic background.