Phospholipid-derived fatty acids microbial classes when in fact those PLFAs are present in a broad range of life forms. Phospholipids can occur in many biological classes (such as in plant roots, fungi, as well as in soil bacteria), so care has to be taken in over-assigning PLFA biomarkers to the wrong class. Even though phospholipids occur in many different life forms, the fatty acid side chains between differing life forms can be quite unique. Polyunsaturated fatty acids ("e.g." 18:3 ω3c) are found in plants, algae and cyanobacteria, but are often not present in bacteria. Monounsaturated fatty acids (particularly at the omega-7 position), odd-chain
Mycorrhiza helper bacteria they found that the bacteria helped ectomycorrhizal fungi promote a symbiotic relationship with the plant by examining an increase in formation of mycorrhiza. Some bacteria improve root colonization and plant growth when associated with arbuscular mycorrhiza. The improvement of growth has been hypothesized that MHB aid the plant to defend against pathogens by improving the nutrient uptake. However, the mechanism these species use to help both of the fungi is still unknown and needs to be further investigated. Actinobacteria are gram-positive bacteria, and they are found in the soil. In this phylum, "Streptomyces" is the largest genus of bacteria, and