Poster Title: Below ground regulation of stress response genes in hybrid poplar
Authors: Joshua R. Herr, Christopher J. Frost, Teodora Orendovici-Best and John E. Carlson
Poster Abstract: Poplar trees, important for woody biomass, respond to biotic and abiotic stresses by inducing defenses that simultaneously confer resistance and tolerance. Jasmonic acid (JA), a plant signaling hormone critical for biotic and abiotic stress response, is also involved in non-defense whole plant carbon allocation. Below-ground ectomycorrhizal fungi increase water and nutrient acquisition in their host plants, but in addition to these benefits they may increase expression of genes within the JA biosynthesis pathway. Key genes involved in the JA pathway have not been characterized. Allene oxide synthase (AOS), a member of the large CYP74 cytochrome P450 family, converts lipoxygenase-derived fatty acid hydroperoxide to allene epoxide, the first dedicated step in JA synthesis. We are characterizing the AOS gene family in Poplar and are investigating biomass allocation shifts and ozone-induced early senescence in Populus-Laccaria model system associated with the expression of AOS.