Targeted plant defense: silicon conserves hormonal defense signaling impacting chewing but not fluid‐feeding herbivores

Johnson, Scott N. and Hartley, Susan E. and Ryalls, James M. W. and Frew, Adam and Hall, Casey R. (2021) Targeted plant defense: silicon conserves hormonal defense signaling impacting chewing but not fluid‐feeding herbivores. Ecology, 102 (3):e03250. pp. 1-7. ISSN 0012-9658


Plants deploy an arsenal of chemical and physical defenses against arthropod herbivores, but it may be most cost efficient to produce these only when attacked. Herbivory activates complex signaling pathways involving several phytohormones, including jasmonic acid (JA), which regulate production of defensive compounds. The Poaceae also have the capacity to take up large amounts of silicon (Si) which accumulates in plant tissues. Si accumulation has anti‐herbivore properties, but it is poorly understood how Si defenses relate to defense hormone signaling. Here we show that Si enrichment causes the model grass Brachypodium distachyon to show lower levels of JA induction when attacked by chewing herbivores. Triggering this hormone even at lower concentrations, however, prompts Si uptake and physical defenses (e.g. leaf hairs) which negatively impact chewing herbivores. Removal of leaf hairs restored performance. Crucially, activation of such Si‐based defense is herbivore‐specific and occurred only in response to chewing and not fluid‐feeding (aphid) herbivores. This aligned with our meta‐analysis of 88 studies that showed Si defenses were more effective against chewing herbivores than fluid‐feeders. Our results suggest integration between herbivore defenses in a model Si‐accumulating plant, which potentially allows it to avoid unnecessary activation of other costly defenses.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Faculty/School / Institute/Centre: Current - Faculty of Health, Engineering and Sciences - School of Sciences (6 Sep 2019 -)
Faculty/School / Institute/Centre: Current - Institute for Life Sciences and the Environment - Centre for Crop Health (24 Mar 2014 -)
Date Deposited: 24 Nov 2020 03:14
Last Modified: 27 Apr 2021 01:26
Uncontrolled Keywords: herbivory, insects, jasmonic acid, plant defense, physical defense, silica, silicon
Fields of Research (2008): 05 Environmental Sciences > 0501 Ecological Applications > 050199 Ecological Applications not elsewhere classified
06 Biological Sciences > 0602 Ecology > 060202 Community Ecology(excl. Invasive Species Ecology)
06 Biological Sciences > 0607 Plant Biology > 060799 Plant Biology not elsewhere classified
Fields of Research (2020): 41 ENVIRONMENTAL SCIENCES > 4102 Ecological applications > 410299 Ecological applications not elsewhere classified
31 BIOLOGICAL SCIENCES > 3103 Ecology > 310302 Community ecology (excl. invasive species ecology)
31 BIOLOGICAL SCIENCES > 3108 Plant biology > 310899 Plant biology not elsewhere classified
Socio-Economic Objectives (2008): D Environment > 96 Environment > 9608 Flora, Fauna and Biodiversity > 960804 Farmland, Arable Cropland and Permanent Cropland Flora, Fauna and Biodiversity
D Environment > 96 Environment > 9604 Control of Pests, Diseases and Exotic Species > 960499 Control of Pests, Diseases and Exotic Species not elsewhere classified
Socio-Economic Objectives (2020): 18 ENVIRONMENTAL MANAGEMENT > 1806 Terrestrial systems and management > 180602 Control of pests, diseases and exotic species in terrestrial environments
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