What do white spruce, spruce budworm andwhite pine blister rust have in common?

All three are the subject of forest ecogenomics researchunder way at the Canadian Forest Service.

Ecogenomics:From Laboratory to Landscape

Ecogenomics is a newdiscipline that studies the structureand function of a genome –the complete set of genes makingup an organism – to gain insightinto the relationship between anorganism and its environment. Ecogenomics tools can be used to monitor and predict how changesin the environment, the landscapeand the climate will affectpopulations and ecosystems.

One gene at a time________________________

Researchers in the fieldof ecogenomics begin bycharacterizing the genome of a particular tree, insect or pathogenspecies. This can be more orless time-consuming dependingon the size of the genome (see table).

Tools can then be developed to testthe organism’s responses to changesin its environment. By investigatingthese interactions in a numberof individuals, it is possible toidentify, for example, populationsor species that are vulnerable toenvironmental change.

Trees: victimsof their longevity?________________________

The adaptation of trees tonew environmental conditionsdepends primarily on the geneticdiversity present in existingpopulations since trees cannot“escape” from adverse changesin their environment. Knowledgeacquired about the molecularmechanisms involved in treeadaptation and stress responses is used in breeding programs.

For example, ecogenomicsresearch is used in marker-assistedselection, a socially acceptableapproach.

Current models for predictingthe impacts of climate changeon forest productivity considerall trees as being equaland therefore as exhibitinguniform responses to changesin environmental conditions.Thanks to ecogenomics, however,researchers can assess genomicvariability in trees and incorporatethis information into the models.This allows tree populations tobe mapped in relation to aspecific agent of change.

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* Rather than compare genomes based on thenumber of genes they comprise, geneticists preferto use the number of nitrogenous bases. Thegenome consists of a set of genes composed ofDNA, which itself contains nitrogenous bases.1 megabase = 100 million bases

White spruce trees growing under homogeneousenvironmental conditions but showing differencesin growth at the same age.Photo: A. Bertrand (Agriculture and Agri-Food Canada)

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Genome size

Number of megabases*

White spruce Between 10,000 and 20,000Human 3,000Poplar 520

SprucebudwormWhite pineblister rust About 100

450

Tree defence responses: identifying the enemy________________________

Trees can come underattack from a variety ofpests. Ecogenomics approachescan be used to study themolecular defence mechanismsthat are induced in treesin response to attacks byspecific pests. The informationthat is acquired can leadto the identification ofnew avenues for increasingtree resistance as well asto a better understandingof how a biological controlmethod influences thephysiological status of a tree.

In light of the globalizationof trade and the ever-greatervolumes of wood beingtransported, ecogenomics can provide diagnostic tools thatuse DNA fingerprinting toidentify insect and pathogenspecies. Some of the pestscurrently under investigationare the emerald ash borer,sudden oak death, scleroderriscanker and poplar canker.

At the heart ofthe tree: fibre________________________

Why are there diameterand height differences among trees in a given plantation?The answer to this questioncan be found by identifyingthe genes responsible forgrowth. Ecogenomics researcherscan also identify genetic traitsrelated to wood quality andselect trees with the desiredwood properties.

Exploiting wintersurvival genes________________________

Spruce budworm outbreaks cause major losses of timber.Researchers at the Canadian Forest Service and UniversitéLaval are working to crackthe genetic code of this insect species through DNA sequencing.They are focusing on genesthat can be exploited in orderto develop pest control tools, such as the genes involvedin winter survival.

Tracking trees atthe molecular level________________________

CFS researchers have developedmolecular tools and modelsto assess the short- and long-termeffects that hybrid trees withexotic components (poplars, for example) have on the geneticdiversity of native species. They can monitor gene flowfrom hybrid poplar plantationsto native trees, and thusprovide useful information forcompanies seeking to obtainor maintain ecocertification fortheir products.

Ecogenomics:a long-term perspective________________________

Because trees live a longtime, the results of geneexpression cannot be observedfor a number of years. Therefore,it is essential to continue forestecogenomics studies over thelong term in order to increasethe competitiveness of theCanadian forest sector.

Useful links________________________

Arborea:http://www.arborea.ulaval.ca/

The DNA barcode:a unique identifier forpathogenic forest fungi:http://cfs.nrcan.gc.ca/pubwarehouse/pdfs/31314.pdf

Impact of exoticpoplars on natural stands:http://cfs.nrcan.gc.ca/publications?id=31064

Using genomicsto enhance forests:http://www.nrcan.gc.ca/com/elements/issues/51/genom-eng.php

© Her Majesty the Queen in Right of Canada 2011 • Catalog Number Fo113-1/68-2011E-PDF • ISBN 978-1-100-19375-5 • ISSN 1705-5784For information regarding reproduction rights, please contact Public Works and

Government Services Canada at: 613-996-6886 or at: droitdauteur.copyright@tpsgc-pwgsc.gc.ca.

For more information, please contact:Nathalie Isabel

Natural Resources CanadaCanadian Forest Service

Laurentian Forestry Centre1055 du P.E.P.S., P.O. Box 10380, Stn. Sainte-Foy

Quebec City, Quebec G1V 4C7Phone: 418-648-7137

Fax: 418-648-5849E-mail: nathalie.isabel@nrcan.gc.ca

Website: cfs.nrcan.gc.ca

Partenariat innovation forêt

Elite white spruceseedlings used for

growth and adaptionstudies in genomics.

Photo: P. Sylvestre (NRCan)

Poplar trees/species showdifferent levels of susceptibilityto rust (Melampsoralarici-populina).Photo: R. Gal (CFS)

Photo: L. Lumley (CFS)

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