The ectomycorrhizae formed between the fungus and host plant can be influenced by soil microorganisms present in the mycorrhizosphere. For example, soil bacteria from the genera "Paenibacillus" and "Burkholderia" alter the branching structure of the root, whereas "Bacillus" species increase root growth and mycorrhizal colonization. The fungus does not require a specific soil but seems to prefer acidic and nutrient-deficient soil. "Suillus luteus" produces hydroxamic acid-based siderophores, which are compounds that can chelate iron and extract it from the soil in nutrient-poor conditions. Ignacio Chapela and colleagues analysed the carbon uptake of "S. luteus" in Ecuador, concluding pine plantations accompanied by "S. luteus" deplete carbon stored in the soil and raising concerns that these might not be a remedy for rising carbon dioxide levels in the atmosphere.