10.5061/DRYAD.DR7SQV9VH
Hall, Casey
0000-0002-6671-1273
Western Sydney University
Mikhael, Meena
Western Sydney University
Hartley, Susan
University of Sheffield
Johnson, Scott
Western Sydney University
Elevated atmospheric CO2 suppresses jasmonate and silicon-based defences
without affecting herbivores
Dryad
dataset
2020
silica
elevated CO<sub>2</sub>
Australian Research Council
https://ror.org/05mmh0f86
ARC FT170100342
2020-03-04T00:00:00Z
2020-03-04T00:00:00Z
en
https://doi.org/10.1111/1365-2435.13549
5399 bytes
2
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
1. Elevated atmospheric CO2 (eCO2) not only increases plant growth but can
also interfere with defence against insect herbivory through the
disruption of the jasmonic acid (JA) pathway. Silicon (Si) plays an
important role in plant stress tolerance and resistance to herbivory,
particularly in grasses, many of which accumulate high amounts of Si.
Activation of the JA pathway has been reported to stimulate Si uptake,
while Si supplementation can alter both constitutive and induced
phytohormone levels. A reduction in JA concentration under eCO2 has the
potential to reduce Si uptake in plants. 2. Using both Si supplemented
(Si+) and control (Si-) plants (Brachypodium distachyon) grown under
ambient (400 ppm) and elevated (640 ppm) CO2 concentrations, we tested how
plant growth, foliar Si concentration and endogenous JA responded to
methyl jasmonate (MeJA) application and the subsequent effects on insect
herbivore performance (Helicoverpa armigera). 3. Elevated CO2 reduced Si
concentration by 19% and endogenous JA by 70% on average. MeJA
significantly increased Si concentration in Si+ plants. Si+ plants had
higher baseline JA levels compared to Si- plants under control conditions
(i.e. no stress), however, when plants were chemically induced with MeJA,
the JA response was on average 84% lower in Si+ plants compared to Si-
plants. Plants without MeJA treatment showed the opposite response, i.e.
Si+ plants had higher baseline JA levels compared to Si- plants. Si
significantly reduced herbivore consumption and growth rate. Despite eCO2
significantly reducing both Si and endogenous JA, no effect was seen on
herbivores feeding on eCO2 plants. 4. Collectively our results suggest
that Si alters the JA response of plants. We show that JA induces Si
uptake, however Si then reduces the JA response of plants under induced
stress conditions. However, predicted increases in CO2 levels within this
century may significantly reduce Si-based mechanical defences against
herbivory via a reduction in endogenous JA.
Data associated with this publication: Hall C, Mikhael M, Hartley S,
Johnson S. (2020) Elevated atmospheric CO2 suppresses jasmonate and
silicon-based defences without affecting herbivores. Functional Ecology.
Files: - Hall_2020_Helicoverpa_JA_data.csv (file containing plant biomass,
caterpillar weights and jasmonic acid data) - Hall_2020_Si_data.csv (plant
silicon measurements) - README_Hall_2020.txt