title: Reduction of rare soil microbes modifies plant-herbivore interactions.
abstract: Rare species are assumed to have little impact on community interactions and ecosystem processes. However, very few studies have actually attempted to quantify the role of rare species in ecosystems. Here we compare effects of soil community assemblages on plant-herbivore interactions and show that reduction of rare soil microbes increases both plant biomass and plant nutritional quality. Two crop plant species growing in soil where rare microbes were reduced, had tissues of higher nutritional quality, which theoretically makes them more susceptible to pest organisms such as shoot-feeding aphids and root-feeding nematodes. Reduction of rare microbes increased aphid body size in the absence of nematodes; nematodes always reduced aphid body size independent of the soil microbial community. This study is the first to show that rare soil microbes are not redundant but may play a role in crop protection by enhancing aboveground and belowground plant defence. It remains to be tested whether these are direct effects of rare soil microbes on plants and herbivores, or indirect effects via shifts in the microbial soil community assemblages.
authors.affiliation: Netherlands Institute of Ecology (NIOO-KNAW), Department of Terrestrial Ecology, Boterhoeksestraat 48, 6666 GA Heteren, The Netherlands. g.hol@nioo.knaw.nl
authors.forename: W H Gera
authors.initials: WH
authors.lastname: Hol
authors.forename: Wietse
authors.initials: W
authors.lastname: de Boer
authors.forename: Aad J
authors.initials: AJ
authors.lastname: Termorshuizen
authors.forename: Katrin M
authors.initials: KM
authors.lastname: Meyer
authors.forename: Johannes H M
authors.initials: JH
authors.lastname: Schneider
authors.forename: Nicole M
authors.initials: NM
authors.lastname: van Dam
authors.forename: Johannes A
authors.initials: JA
authors.lastname: van Veen
authors.forename: Wim H
authors.initials: WH
authors.lastname: van der Putten
mesh_terms: D000818:Animals; D001042:Aphids / Q000382:microbiology / Q000502:physiology*; D001419:Bacteria / Q000145:classification* / Q000302:isolation & purification; D018407:Bacterial Physiological Phenomena; D027461:Beta vulgaris / Q000382:microbiology / Q000502:physiology*; D001937:Brassica / Q000382:microbiology / Q000502:physiology*; D005658:Fungi / Q000145:classification* / Q000302:isolation & purification / Q000502:physiology; D009348:Nematoda / Q000254:growth & development* / Q000382:microbiology / Q000502:physiology; D012988:Soil Microbiology; D013242:Sterilization