Nitrogen-fixing plants provide the major biological source of nitrogen for the biosphere, and are particularly important in low-nutrient environments. Actinorhizal symbiosis is a strong contributor to global biological nitrogen fixation process. These soil bacteria are plant symbionts that have a broad host-recognition-specificity. Inter-planting actinorhizal plants with suitable tree crops allows nurse cropping of valuable tree species such as walnut. These rapidly growing plants have been used as biomass for fuel or pulp. Actinorhizal plants have been successfully used to re-colonize and reclaim land that has been industrial wasteland including lands spoiled by metaliferous mine spoils and smelter waste. Frankia will bind and sequester several toxic heavy metals and it has potential bioremediation and phytoremediation applications especially on heavy-metal-contaminated land.
Symbiotic interactions between Frankia and the host plant are not well understood. By sequencing several strains of Frankia, researchers hope to identify common core genes and genes involved in adaptation to stressful environmental conditions. Aside from learning more about the plant-microbe interactions and applying the information to breeding and management of bioenergy crops, another potential application of the genome sequences is in bioremediation to sequester heavy toxic metals and clean lands contaminated with heavy metals.
Principal Investigators: Louis Tisa, University of New Hampshire
Program: CSP 2010