Drought tolerance and growth enhancement of hybrid poplar by inoculation with an endophyte consortium
S. DOTY (1), Z. Khan (1), H. Rho (1), A. Firrincieli (2), S. Hung (1), V. Luna (3), O. Masciarelli (3), S. Kim (1) (1) University of Washington, U.S.A.; (2) University of Tuscia, Italy; (3) Universidad Nacional de Río Cuarto, Argentina

With increasing effects of global climate change, there is a strong interest in developing biofuels from trees that have high C sequestration rates and relatively low chemical inputs. Using plant-microbe symbiosis to maximize plant growth and increase host stress tolerance may improve the economic viability and environmental sustainability of poplar as a feedstock. Based on our previous research, a consortium of microbial endophyte strains of 10 different species were selected to investigate the effects of inoculation on commercial hardwood cuttings of Populus deltoides X Populus nigra clone OP-367. After 1.5 months of non-stress conditions followed by one month of water stress, plants inoculated with the consortium had 28% greater total biomass than mock-inoculated control plants. Inoculation also improved photosynthesis (Fv/Fm) by 33% and reduced damage by reactive oxygen species (ROS). Inoculated plants had higher chlorophyll content (66%) and lower stomatal conductance (33%) compared to the mock-inoculated plants. To begin to determine the mechanisms involved, in vitro production of phytohormones by the strains was assayed. As the genomes of several of the strains were recently sequenced, a genomic analysis was conducted for the presence of genes implicated in being involved in conferring drought tolerance. The results suggest the potential role of endophytes in the modulation of the plant host stress response by multiple mechanisms.

Abstract Number: P2-22
Session Type: Poster