María Rosario García-Gil - Forest Tree Genetics and Breeding

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The research of my group focuses on traits with economic value (e.g. growth, wood formation, wood calorimetric content, frost hardiness and pest resistance) and traits with clear adaptive value (e.g. timing of budset). These traits are very complex and called "quantitative trais" because they are controlled by a large number of genes and gene interactions.
Rosario_Garcia_portrait

Molecular tools to assist tree breeding
The main contribution of molecular tools to conventional tree breeding is the possibility they provide of early selection to shorten the breeding cycle.
The Quantitative Trait Loci (QTL)-Candidate Gene co-location approach prevents the loss of desired QTLs during recurrent selection, and its high resolution allows breeders to break up undesired trait correlations. We are building a genetic map on a Scots pine (Pinus sylvestris) full sib family of 500 offspring based on AFLP, SSR and SNP markers. We search for co-location of genes (SNPs) with QTLs for growth, spiral grain, timing of budset, frost hardiness and Heterobasidion resistance.
Association Mapping (AM) is another genetic strategy to unravel the genetics behind complex traits. This is a candidate gene-based method which tests for association between candidate genes and phenotypic variation at a population level. With this approach, we intend to identify genes underlying wood formation in Norway spruce and wood calorimetric content in Scots pine.
Genome Wide Selection (GWS) to detect genomic regions harbouring sequence variants that affect complex traits requires the development of arrays scanning for single molecule changes in the genome (SNP). Conceptually, this method is simple and opens the possibility to incorporate high-throughput genomic tools into operative tree breeding. In my group, we are developing a dense SNP array in Scots pine for its application in an advanced Scots pine breeding pedigree.


Bud formation in one-year-old Scots pine seedlings under greenhouse conditions.		Scots pine trees

Spatial Genetic Structure in Scots pine
Differences in genetic structure between tree species are due mainly to differences in life form and breeding system. The availability of highly variable molecular markers has facilitated fine-scale genetic structure analysis of natural tree populations. Inbreeding depression is an important issue in forestry, due to the poor performance of inbred trees. We investigate the impact of a common forest management strategy, natural seedling regeneration from seed trees, on fine-scale spatial genetic structure.

Genetics underlying forest tree adaptation

Single Nucleotidy Polymorphisms (SNPs) scoring

The southwards transfer of Scots pine leads leads to increased growth, but not sufficient to overcome the competitive advantages of the local southern trees. In other words, temperature is not the only factor limiting the growth potential of northern populations. There is much evidence that day length is another major environmental cue shaping the strong adaptive cline in Scots pine. Less attention has been devoted to the study of light composition (wavelength). We are therefore studying the effect of light quality on three month-old Scots pine seedlings. We aim to use proteomics, chemical analyses and microscopy as tools to identify strong associations with genes involved in local adaptation to light composition.

Conifer genome evolution
Gene families control important traits in forest trees, such as frost hardiness, pest resistance, and growth, so tree breeding success depends on a good understanding of the composition and function of those gene families'. Conifers have large genome sizes compared with most animal and plant species. However, how and why conifers have evolved such large genomes is not understood. Based on our work on the phytochrome gene family, we have found that conifer gene families can be very complex and contribute to the enormous size of the conifer genome. In the light of our recent findings, we are investigating the composition and function of another important gene family (LP3) involved in water deficit stress.

Svensk samanfattning

Key publications

Komulainen P, Brown GR, Mikkonen M, Karhu A, García-Gil MR, O'Malley D, Lee B, Neale DB and Savolainen O (2003). Comparing EST-based genetic maps between Pinus sylvestris and Pinus taeda. Theor App Genet 107: 667-678

García-Gil MR, Mikkonen M, Savolainen O (2003). Nucleotide diversity at two phytochrome loci along a latitudinal cline in Pinus sylvestris. Mol Ecol. 12: 1195-1206

Waldmann P, García-Gil MR, Sillanpaa MJ (2005). Comparing Bayesian estimates of genetic differentiation of molecular markers and quantitative traits: an application to Pinus sylvestris. Heredity 94: 623-629

Notivol E, García-Gil MR, Alía R, Savolainen O (2007). Genetic variation of growth rhythm traits in the limits of a latitudinal cline in Scots pine. Can J For Res 37: 540-551

García-Gil MR (2008) Evolutionary aspects of functional and pseudogene family in Scots pine. J Mol Evol 67(2): 222-232

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May 2012

Friday, May 18, 2012
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