The Functional Characterization of the SLC Gene in Populus trichocarpa, and its Potential Role in Lignin Biosynthesis




Irwin, Tyler
Tran, Lan
Ehlting, Jürgen

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Wood is an extraordinary, sustainable feedstock for construction, pulp and paper, and potentially for bioenergy production. Wood is largely composed of secondary cell walls containing carbohydrates (such as cellulose) and lignin. The latter provides mechanical stability, but negatively impacts pulp and bioethanol generation. To better understand the genetic architecture of wood biogenesis, genome wide genetic association studies have been performed previously, linking genetic variation within a population of poplar trees with wood trait variations. Among other genes, it was suggested that a putative solute carrier gene, named SLC, in Populus trichocarpa was genetically associated with secondary cell wall biogenesis and lignin biosynthesis. SLC belongs to a large family of transporters involved in nitrate, peptide, and secondary metabolite transport, but its actual physiological function is unknown. The connection and possible role of SLC in secondary cell wall biogenesis will be examined in my Honours research by using reverse genetic approaches: Poplar trees and isolated roots will be used to characterize transgenic plants overexpressing or down-regulating SLC. The mutants will be analyzed through chemical analysis using HPLC to test for changes in secondary metabolites in the mutants compared to wild-type. Furthermore, a nutrient experiment will be performed by growing mutant whole plants under different nitrogen fertilization regimes. This will test the hypothesis that differences in nutrient uptake efficiencies may indirectly explain the observed association of SLC with wood chemistry traits. In summary, the purpose of this project is to gain insight into the biological role of SLC using a functional genomics approach.



lignin, reverse-genetics, poplar, solute carrier, transporter