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12 April
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31 December 2006

Mise au point de méthodes de caractérisation de céréales basées sur les marqueurs moléculaires

Setting of cereal characterization methods based on molecular markers

Context

The plant productions are now currently generated with a perspective of traceability, authentification and different agricultural products are under certification process. Therefore, reliable techniques of analysis must permit their characterization and their follow-up in the different channels. Concerning the cereals, the official criteria’s of identification and analyses, notably those used at the time of the enrolment of varieties in the official catalogue in view of commercial use, are those of the UPOV (DHS tests: distinction, heritability and stability); these criterias rest on expressed characters, of morphological type. Other expressed characters as biochemical markers like the seed proteins in cereals (glutenins, gliadins) are also officially recognized. Moreover, high molecular weight glutenins are also associated to the baking quality of bread and therefore the determination of allelic composition of the variety should permit a prediction of the technological value of the baking quality.
The development of molecular biology techniques, mainly those linked to the analysis of the DNA support of the heredity, offer the possibility to increase fields and the number of the molecular markers. Every marker permitting the visualization of a polymorphism at a locus informs on the genotype of the individual at this locus or at the adjacent one. These markers permit the characterization of the plant variety independently of external culture conditions, using a genetic profile achieved on DNA extract from any plant organ (leaves, seeds,…). Different markers exist; the most current are the microsatellites and the EST.
These different molecular markers are considered therefore as complementary and are in trials on several species in the DHS tests notably for wheat.

Objectives

Objectives of this project aim to develop as routine way the application of protein and molecular markers on wheat in the accreditation setting according to the 17025 norm. The project intend to establish the identity of varieties and the prediction of the baking quality.
We will develop analyses of high molecular weight glutenin by electrophoresis on acrylamide gel. Considering the molecular markers, we will privilege in a first time markers of microsatellites and the EST types.

Expected results

The objective is to exploit these markers in the scoop of analyses done under accreditation according to the ISO 17025 norm. The routine analyses using the different markers are in progress on cereals in different research programs of the department. We also proceed to comparisons and to the assessment of the different molecular markers. Finally, it could be able to characterize a variety and the alleles composition of high molecular weight glutenin, and on the other hand with the help of molecular markers and by comparison with controls or data bases, to permit the identification of a variety.

Results obtained

The molecular techniques are developed since several years in the laboratory. Protein markers are used in the prediction tests of the baking quality of wheat flour. Indeed, it has been demonstrated that some alleles of high molecular weight glutenin are associated preferentially to the technological properties of the flour. These glutenins constitute one of the 4 classes of the wheat seed proteins. They are following grain grinding and extraction, separated by electrophoresis on acrylamide gel. The presence of alleles of quality allows to infer the baking quality of the variety. This test achieved during a screening performed in a selection design, constitutes a help to the decision at the time of the choice of family lines under selection (at F3-F5); the breeder can direct the selection of the line toward the yield or the quality channel . This analysis on acrylamide gel also provides a typical profile, reference of the variety, that can also be used to characterize it subsequently.
During the last years, various molecular markers have been developed and have been used in the laboratory in wheat, barley and spelt research programs. We used the RFLP, RAPD, AFLP microsatellites and EST markers. These EST, or expressed sequence tags, were sequenced and some have been shown to contain microsatellites repeats. These microsatellite markers, located in an expressed sequence, are very easy to analyse.

Partners

Ducourouble M , Jorion et Fils Frasnes-lez-Buissenal
Dekeyser A., Département de Lutte biologique et Ressources Phytogénétiques, CRA-W
Dr Sinnaeve G., Département qualité, CRA-W
Herman J.L., Département Production végétale, CRA-W

Funding

  • DGARNE

Team

Laurence KUTTEN Yordan MUHOVSKI
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