FAIR-CT96-5004 Genetic fingerprinting of hardwood trees and application of molecular techniques to characterise gene expression and physiological states

Contacts




To find similar Items, click on a keyword below:
Crops for Solid Wood Products : FAIR Area 1.3 - Forestry-Wood Chain : FAIR Marie Curie Research Training Grants

Objectives:

The initial aim of the project was to produce arbitrary molecular markers (RAPDS) for five species of broadleaved trees (Quercus petreae, Q. robur, Fraxinus excelsior, Prunus avium and Acer pseudoplatanus) by the use of the PCR method and arbitrary oligonucleotide primers. The technique although useful for a great number of species has been widely criticised for the lack of reproducibility from laboratory to laboratory and from user to user. It was also judged inappropriate as a tool for evaluating biodiversity. At the start of the prject, the general trend in plant genetics was a move to the characterisation and the use of microsatellite loci as molecular markers. It was said that these microsatellite polymorphisms displayed all the required criteria to make them the best markers available. A molecular marker must be highly polymorphic, display a co-dominant inheritance allowing homo- and heterozygotic states in diploid organisms to be identified, occur frequently, be evenly distributed in the genome and display a selectively neutral behaviour. It also must be of easy access, quickly assayed, be highly reproducible and must allow easy exchange of data between laboratories. All these qualities are displayed by the microsatellite loci.

Activities and Results:

The emphasis shifted slightly from a project entirely based on RAPD to a new approach involving the analysis of microsatellites. Thee reasons behind this change were: the first sequences of microsatellite regions for Quercus robur and Quercus macrocarpa were published or available in GenBank; the development and the accessibility of the more recent method of DNA library enrichment in microsatellites; and the recent availability of a new sequencing device with precast sequencing gels.

Activities and results: The elite collections of different trees, made available by the Irish forestry company, Coillte, enabled the analysis of a greater genetic diversity which could be improved and optimised in the future for the benefit of new forests management, with the use of these microsatellite markers. The choice of microsatellites against RAPD has proved to be right and very rewarding in terms of knowledge that was gained. The results, particularly the Fraxinus microsatellite sequences and amplifying primers, have been made available as quickly as possible for the benefit of the scientific community through publication in GenBank and the publication of primers in TreeGenes Database.

Conclusions:

This new knowledge will be very useful for genetic structure, pollen dispersal, parentage analysis and taxonomy studies in a broad range of Fraxinus species and other Oleaceae species in which some of these microsatellites markers of F. excelsior have been shown to amplify. These microsatellites are already being used by one French team and one Greek team. Three other European teams have the expressed intention of using these sequences.

Keywords: Genetic fingerprinting, hardwood trees, molecular markers

Contacts

Scientific Supervisor

• Gerry (Gerard) DOUGLAS / TEAGASC Kinsealy Research Centre / IRELAND