Characterization among and within Sicilian Tetraploid Wheat Landraces by Gluten Protein Analysis for Traceability Purposes.

The criteria of "Distinctness, Uniformity and Stability" as well as a high "overall quality index" are used to register the Italian modern varieties to the national register. Differently, local conservation varieties can be certified under different EU Directives that facilitate, as an overall objective, the preservation of biodiversity and the containment of genetic erosion. In recent years, products derived from ancient grains are perceived to be healthier and more sustainable by consumers, especially in Italy, with consequent higher market prices. The ancient tetraploid wheat varieties registered in the national register of conservation varieties amount to 28, 24 of which are Sicilian. They are supposed to have wide genetic variability compared to modern ones, making them vulnerable to fraud because they are difficult to trace. It is therefore important to have tools able to discriminate between autochthonous Sicilian varieties. This can be completed by gluten proteins composition, which also provides information on the technological properties of derived products. Fifty-one accessions belonging to twenty-two ancient varieties of Sicilian tetraploid (mostly durum) wheat were analyzed. Although wide intra-accession and intra-varietal variability measurements were assessed, the gliadin pattern of bulks of seeds belonging to each variety was discriminatory. Moreover, differences in technological attitudes were found between landraces. This paves the way to use gluten protein patterns for traceability, allowing local farmers and producers to valorize their products and assure consumers regarding the transparency of the entire supply chain.

A Digital PCR Assay to Quantify the Percentages of Hulled vs. Hulless Wheat in Flours and Flour-Based Products.

Several food products, made from hulled wheats, are now offered by the market, ranging from grains and pasta to flour and bakery products. The possibility of verifying the authenticity of wheat species used at any point in the production chain is relevant, in defense of both producers and consumers. A chip digital PCR assay has been developed to detect and quantify percentages of hulless (i.e., common and durum wheat) and hulled (i.e., einkorn, emmer and spelt) wheats in grains, flours and food products. The assay has been designed on a polymorphism in the miRNA172 target site of the AP2-5 transcription factor localized on chromosome 5A and involved in wheat spike morphogenesis and grain threshability. The assay has been evaluated even in a real-time PCR system to assess its applicability and to compare the analytical costs between dPCR and real-time PCR approaches.

Digital PCR for Genotype Quantification: A Case Study in a Pasta Production Chain.

Digital polymerase chain reaction (dPCR) is a breakthrough technology based on the partitioning of the analytical sample and detection of individual end-point amplifications into the separate compartments. Among the numerous applications of this technology, its suitability in mutation detection is relevant and characterized by unprecedented levels of precision. The actual applicability of this analytical technique to quantify the presence of a specific plant genotype, in both raw materials and transformed products, by exploiting a point polymorphism has been evaluated. As proof of concept, an Italian premium pasta production chain was considered and a dPCR assay based on a durum wheat target variety private point mutation was designed and evaluated in supply-chain samples. From the results obtained, the assay can be applied to confirm the presence of a target variety and to quantify it in raw materials and transformed products, such as commercial grain lots and pasta. The performance, costs, and applicability of the assay has been compared to analytical alternatives, namely simple sequence repeats (SSRs) and genotype-by-sequencing based on Diversity Arrays Technology sequencing (DArTseqTM).

Digital PCR: What Relevance to Plant Studies?

Digital PCR (dPCR) is a breakthrough technology that able to provide sensitive and absolute nucleic acid quantification. It is a third-generation technology in the field of nucleic acid amplification. A unique feature of the technique is that of dividing the sample into numerous separate compartments, in each of which an independent amplification reaction takes place. Several instrumental platforms have been developed for this purpose, and different statistical approaches are available for reading the digital output data. The dPCR assays developed so far in the plant science sector were identified in the literature, and the major applications, advantages, disadvantages, and applicative perspectives of the technique are presented and discussed in this review.

Evaluation of amplified fragment length polymorphism and simple sequence repeats for tomato germplasm fingerprinting: utility for grouping closely related traditional cultivars.

Cultivated tomato (Solanum lycopersicum L.) germplasm shows limited genetic variation. Many DNA marker systems have been used for genetic diversity studies in wild and cultivated tomatoes, but their usefulness for characterizing phenotypic differences among very closely related cultivars remains uncertain. We have used 19 selected simple sequence repeat (SSR) markers and 7 amplified fragment length polymorphism (AFLP) primer combinations to characterize 48 cultivars of tomato, mainly traditional cultivars from the south-east of Spain. The main types were Solanum lycopersicum L. 'Muchamiel', 'De la pera', and 'Moruno'. The robustness of the dendrograms and the discrimination power reached with each marker type were similar. Unique fingerprinting even of the most closely related tomato cultivars could be obtained using a combination of some SSR and AFLP markers. A better grouping of the 'Muchamiel' cultivars was observed with SSR markers, whereas the grouping of cultivars of 'De la pera' type was best achieved with AFLPs. However, both types of markers adequately grouped cultivars of the main types, confirming the utility of SSR and AFLP markers for the identification of traditional cultivars of tomato.