Reduction of rare soil microbes modifies plant-herbivore interactions.
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.
Hol
W H Gera
WH
Netherlands Institute of Ecology (NIOO-KNAW), Department of Terrestrial Ecology, Boterhoeksestraat 48, 6666 GA Heteren, The Netherlands. g.hol@nioo.knaw.nl
de Boer
Wietse
W
Termorshuizen
Aad J
AJ
Meyer
Katrin M
KM
Schneider
Johannes H M
JH
van Dam
Nicole M
NM
van Veen
Johannes A
JA
van der Putten
Wim H
WH
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