“Symbiosis, a range of intimate relationships Plants, animals, and diverse microbes engage in a wide range of interactions that can be characterized as symbiotic, that is, the living together of unlike NVP-AUY922 organisms [1–5]. The Plant-Associated Microbe Gene Ontology (PAMGO) Consortium
 has been developing an extensive set of Gene Ontology (GO)  terms that describe processes and structures underlying symbiotic interactions between organisms, ranging from mutualists through parasites . This mini-review focuses on the nutrient acquisition selleckchem strategies of a range of symbiotic organisms. Here “”nutrient”" is defined as any chemical substance required for metabolism or development. GO terms that describe gene products related to nutrient exchange during symbiosis are discussed along with examples of symbioses involving bacteria, protozoans, fungi, animals, oomycetes, algae, and plants. The Gene Ontology The GO is a controlled vocabulary consisting of GO terms that describe gene product attributes in any organism . GO terms are arranged as directed acyclic graphs (DAGs) within three ontologies, “”GO: 0005575 cellular
component”", “”GO: 0008150 biological process”", and “”GO: 0003674 molecular function”". DAGs differ from hierarchies in that each term (child) may be related to more than one less specific term (parent). Three specific relationships among parent and child terms within a DAG are currently recognized by the GO: “”is_a”", “”part_of”", and “”regulates”". For example, “”GO: 0052010 catabolism by symbiont of host cell wall I BET 762 cellulose”" Methocarbamol is a type of “”GO: 0052009 disassembly by symbiont of host cell wall”", and thus these terms would be
connected by the “”is_a”" relationship (for more information on term-term relationships and ontology structure, see ). The concept of symbiosis in the Gene Ontology In the GO, the concept of symbiosis is represented by the term “”GO: 0044403 symbiosis, encompassing mutualism through parasitism”", which is defined as: “”An interaction between two organisms living together in more or less intimate association. The term host is usually used for the larger (macro) of the two members of a symbiosis. The smaller (micro) member is called the symbiont organism”" . The various forms of symbiosis include parasitism, in which the association is disadvantageous or destructive to the host organism; mutualism, in which the association is advantageous to both; and commensalism, in which the symbiont benefits while the host is not affected . However, mutualism, parasitism, and commensalism are not discrete categories of interactions but rather a continuum. In fact, the nature of a symbiotic interaction may vary due to developmental changes in the host or symbiont, changes in the biotic or abiotic environment, or variation in host genotype . Correspondingly, the exchange of nutrients between symbiotic partners may be context dependent and may be bidirectional or heavily unidirectional.