Functional discovery and characterization of genes and alleles affecting wood biomass yield and quality in poplar using activation tagging and association genetics
Investigators: Busov, V; Tuskan, G, Yordanov, Y; Sykes, R; Muchero, W.
Institutions: Michigan Technological University, Oak Ridge National Laboratory, National Renewable Energy Laboratory
Non-Technical Summary: The goal of this project is to discover and characterize novel genes and alleles that affect wood biomass yield and quality in Populus. These discoveries can enable knowledge-based approaches for development of specialized bioenergy poplar cultivars. We will employ a two stage approach, using activation tagging as a functional gene discovery tool followed by intensive search and validation of functional alleles that can be deployed through traditional breeding or genetic engineering. Our approach is combining the strengths of mutagenesis for functional identification of genes with the power of next generation sequencing technologies for identification of alleles with breeding values.
Objectives: (1) Screen a population of 5,000 activation tagged lines for changes in woody biomass quality and yield. (2) Identify tagged genes in all mutants through positioning in the genome and validation of activation. (3) Recapitulate through retransformation the effect of 20 tagged genes prioritized by novelty and severity of the phenotype. (4) Use the resequencing and phenotypic data for 1,100 Populus trichocarpa individuals to identify rare genotype-phenotype associations in the population of the +160 tagged genes. (5) Validate the effect of approximately 20 rare alleles prioritized by strength of genotype by phenotype associations through transformation experiments.
Approach: Biomass yield will be estimated through stem biometric measurements of greenhouse-grown plants. Screening for changes in cell wall composition will be performed by molecular beam mass spectrometry (PyMBMS) Modifications in physical wood properties like green wood density, basic wood density, moisture content and modulus of elasticity (MOE) will also be determined. For all mutants, we will clone the gene that caused the phenotype via mapping the position of the activation tag insertion in the poplar genome, followed by validation of the proximal gene(s) activation. For all tagged genes we will identify alleles which are tightly associated with biomass yield and quality traits. We will utilize a population encompassing 1,100 natural Populus trichocarpa genotypes clonally propagated in replicated common gardens in four Pacific north-west locations as a population-based validation step. We will select approximately 20 alleles prioritized by the strength of the genotype-phenotype associations and validate their effect through transgenic transfers.
Name: Victor Busov