plant, but also between different plants in a landscape. The main groups include ectomycorrhizae, arbuscular mycorhizae, ericoid mycorrhizae, orchid mycorrhizae, and monotropoid mycorrhizae. Monotropoid mycorrhizae are associated with plants in the monotropaceae, which lack chlorophyll. Many Orchids are also achlorophyllous for at least part of their life cycle. Thus these mycorrhizal-plant relationships are unique because the fungus provides the host with carbon as well as other nutrients, often by parasitizing other plants. Achlorophyllous plants forming these types of mycorrhizal associations are called mycoheterotrophs. Endophytes Endophytes grow inside the plant tissues - roots, stems, leaves - mostly symptomless, however when plant ages they can become slightly pathogenic. They may colonize inter-cellular spaces, the root cells themselves, or both. Rhizobia and dark septate endophytes (which produce melanin, an antioxidant that may provide resilience against a variety of environmental stresses) are famous examples. Bacteria Zone of soil surrounding the roots is rich in nutrients released by plants and is therefore attractive growth medium for both beneficial and pathogenic bacteria. Root associated beneficial bacteria promote plant growth and provide protection from pathogens. They are mostly rhizobacteria that belong to Pseudomonadota and Bacillota, with many examples from Pseudomonas and Bacillus genera. Rhizobium species colonize legume roots forming nodule structures. In response to root exudates, rhizobia produce Nod signalling factors that are recognized by legumes and induce formation of nodules on plant roots. Within these structures Rhizobium perform nitrogen fixation that proves plant with nitrogen source. In turn, plants provide bacteria with carbon source to energize the nitrogen fixation. In addition to nitrogen fixation, Azospirillum species promote plant growth through production of growth phytohormones (auxins, cytokinins, gibberellins). Due to these phytohormones root hairs expand to occupy larger area and better acquire water and nutrients. Pathogenic bacteria that infect plants infect plant roots are most commonly from Pectobacterium, Ralstonia, Dickeya and Agrobacterium genera. Among the most notorious are Pectobacterium carotovorum, Pectobacterium atrosepticum, Ralstonia solanacearum, Dickeya dadanthi, Dickeya solani and Agrobacterium tumefaciens. Bacteria attach to roots in a certain biphasic mechanism with two steps – first weak, non-specific binding and then switch to second – strong irreversible residence phase. Both beneficial and pathogenic bacteria attach in this fashion. Bacteria can stay attached to the outer surface or, certain endophytes or pathogens can colonize the inner root. Primary attachment is governed by chemical forces or certain extracellular structures such as pili or flagella. Secondary attachment is mainly characterized by