title: Parasponia: a novel system for studying mutualism stability.
abstract: Understanding how mutualistic interactions are stabilized in the presence of cheaters is a major question in evolutionary biology. The legume-rhizobia mutualism has become a model system for studying how plants control cheating partners. However, the generality and evolutionary origins of these control mechanisms are intensely debated. In this Opinion article, we argue that a novel system--the Parasponia-rhizobia mutualism--will significantly advance research in mutualism stability. Parasponia is the only non-legume lineage to have evolved a rhizobial symbiosis, which provides an evolutionary replicate to test how rhizobial exploitation is controlled. Evidence also suggests that this symbiosis is young. This allows studies at an earlier evolutionary stage in mutualisms, so the origin of control mechanisms can be better understood.
authors.affiliation: Department of Ecological Science, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1085, 1081HV Amsterdam, The Netherlands. Electronic address: jebehm@gmail.com.
authors.forename: Jocelyn E
authors.initials: JE
authors.lastname: Behm
authors.affiliation: Department of Plant Science, Laboratory of Molecular Biology, Wageningen University, Drovendaalsesteeg 1, 6709PB Wageningen, The Netherlands.
authors.forename: Rene
authors.initials: R
authors.lastname: Geurts
authors.affiliation: Department of Ecological Science, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1085, 1081HV Amsterdam, The Netherlands.
authors.forename: E Toby
authors.initials: ET
authors.lastname: Kiers
mesh_terms: D005075:Biological Evolution; D007887:Fabaceae / Q000382:microbiology; D012231:Rhizobium / Q000502:physiology*; D013559:Symbiosis / Q000502:physiology
keywords: Trema; cooperation; defection; partner choice; rhizobia; sanctions