Genome-Enabled Modification of Poplar Root Developme...

Genome-Enabled Modification of Poplar Root Development for Increased Carbon SequestrationMore than 90% of total root lengthproduced by mature temperate trees can be accounted for by small lateral roots. In order to enhance carbon storage in therhizosphere, we need a better understanding of the way in which trees regulate lateral root formation. The goal of this project isto use the poplar genome sequence to identify and functionally characterize key regulators of lateral root proliferation in poplar,as means of increasing carbon storage in the soil. Objectives are: 1) use the poplar genome to isolate poplar orthologs of allknown root development regulators; 2) identify novel genes affecting lateral root formation by screening existing activation taggingand gene/enhancer trap populations in Populus; 3) test the effects of over-expressing and silencing all candidate genes in twogenotypes of poplar exhibiting contrasting rooting behavior; 4) evaluate the effects of these genetic manipulations on rootformation and architecture under greenhouse conditions; and 5) conduct metabolic profiling to identify metabolic alterationsassociated with our genetic manipulations. ORNL is primarily responsible for task 5 which includes conducting metabolic profiling onall transgenic and non-transformed control lines, and expanding the mass spectral database of profiled metabolites to 1000metabolites.