BETWOOD · Identification of novel regulators of growth and wood formation by studying natural variation in Arabidopsis and Betula pendula, a novel model tree

My research aims to understand molecular mechanisms controlling growth and wood formation in plants. I will identify novel genes functioning in the regulation of cambial meristem activity by exploring its natural variation. I will use two complementary model species: herbaceous Arabidopsis and forest tree silver birch (Betula pendula). In Arabidopsis, I will identify genetic quantitative trait loci (QTL) associated with wood formation through a genome-wide association (GWA) study of sequenced accessions (ecotypes). I will further functionally study the role of causative genes in secondary development. I will also introduce a novel, second generation model species, B. pendula, into tree genetics. This tree is monoecious (both female and male flowers at the same tree), and tolerates inbreeding well. Even six months old trees can be induced to flower under greenhouse conditions, making advanced crossing schemes possible. Its small genome is currently being sequenced. Betula will bring the power of inbreeding and short generation times into tree genetics. A great resource for my Betula research is a collection of tree morphology and wood formation mutants established by my collaborator, Finnish Forest Research Institute. These mutants include trees with atypical tension wood formation, cambial activity, stem branching, branch morphology and secondary metabolite content. I will identify the causative mutations behind these phenotypes, and functionally study their role in tree development. For my future research, I will further explore natural variation in tree morphological and wood formation related traits. I will establish a collection of inbred tree lines, a QTL mapping population, a common garden of diverse birch ecotypes and a hybrid collection of interspecies crosses between different species of Betula genus. With Betula as a model tree, my project represents a novel approach of tree genetics, which has potential for ground-breaking insights into wood development.