Vesicular-arbuscular mycorrhizal (VAM) fungi
VAM form a beneficial interaction with a wide range of plants, including horticultural and forage field crops. The fungi promote efficient nutrient absorption and increase plant growth and yield. VAM interactions with the soil play an important role in controlling soil fertility, soil erosion and plant water stress. Overall, using VAM fungi in crop production should reduce fertilizer amounts applied to farmland. The importance of VAM fungi to sustainable agriculture and the ecosystem has led to its commercial development. However, for the past thirty years, progress on VAM cultivation has not been very successful, partly because the research is very difficult and time consuming. ARS researchers have found optimal conditions for propagating the dual culture of root and fungus. Pure and clean VAM fungi can be grown on gel plates in a completely reproducible manner. As a result of this breakthrough, many billions of fungal spores may be produced in test tubes.
http://www.ars.usda.gov/research/patents/patents.htm?serialnum=09737975
