Rabea Schweiger1,2, Anna-Maria Heise1, Marcus Persicke2, Caroline Müller1,2

1Department of Chemical Ecology,1,2Center for Biotechnology (CeBiTec),

Bielefeld University

Specificity of metabolic plant responses to salicylic and jasmonic acid and impacts on chewing and sucking herbivores

Herbivores

Piercing-sucking

Chewing-biting

Pathway interference metabolic outcome ?

JA-mediated defences

Jasmonic acid (JA)

Schweiger, Heise, Persicke, Müller - Chemical Ecology - Bielefeld University, Germany

Feedback onherbivores?

SA-mediated defences

Salicylic acid (SA)

Theoretical effects of phytohormones on plant chemistry

JA-mediated pathway SA-mediated pathway

JA-specific targets

SA-specific targets

Interaction targets

Common targets

-

SA targets inhibited by JA

JA targets inhibited by

SA

Schweiger, Heise, Persicke, Müller - Chemical Ecology - Bielefeld University, Germany

Theoretical effects of phytohormones on plant chemistry

JA-mediated pathway SA-mediated pathway

JA-specific targets

SA-specific targets

Interaction s

Common targets

-

SA targets inhibited by JA

JA targets inhibited by

SA

Schweiger, Heise, Persicke, Müller - Chemical Ecology - Bielefeld University, Germany

Analyses of leaf AND phloem exudate metabolites

Plantago lanceolata

Daily application of phytohormones Control (0.01% Triton, pH 3.1) JA (0.5 mM) SA (0.5 mM) JA + SA (0.5 mM each) JA + SA (0.25 mM each)

Schweiger, Heise, Persicke, Müller - Chemical Ecology - Bielefeld University, Germany

JA (0.5 mM)

Effects of phytohormones on leaf / phloem metabolomeafter 72 h (2 treatments)

significance (U test, P < 0.05)

Volcano plots

fold change (<0.5, >2)

Leaves: 1,414 features, phloem: 36 metabolites N = 10; Mann-Whitney U-tests

Schweiger, Heise, Persicke, Müller - Chemical Ecology - Bielefeld University, Germany

JA (0.5 mM)

SA (0.5 mM)

Phytohormone-specific modulation of metabolic pool sizes

Effects of phytohormones on leaf / phloem metabolomeafter 72 h (2 treatments)

Some overlap in responses

Leaves: 1,414 features, phloem: 36 metabolites N = 10; Mann-Whitney U-tests

Effects of phytohormones on leaf / phloem metabolomeafter 72 h (2 treatments)

Schweiger, Heise, Persicke, Müller - Chemical Ecology - Bielefeld University, Germany

JA + SA (0.25 mM)

JA + SA (0.5 mM)

• Changes in metabolite pool sizes depend on applied conc.

Leaves: 1,414 features, phloem: 36 metabolites N = 10; Mann-Whitney U-tests

No effects on typical targets (iridoid glycosides)

Effects of phytohormones on leaf / phloem metabolomeafter 72 h (2 treatments with 0.5 mM concentrations)

Increased

Schweiger, Heise, Persicke, Müller - Chemical Ecology - Bielefeld University, Germany

Effects of phytohormones on leaf / phloem metabolomeafter 72 h (2 treatments with 0.5 mM concentrations)

Increased

Decreased

Schweiger, Heise, Persicke, Müller - Chemical Ecology - Bielefeld University, Germany

• Induction pattern fits to theoretical framework• In phloem exudates mainly down-regulation

-

Effects of phytohormones on leaf / phloem metabolomeafter 72 h (2 treatments with 0.5 mM concentrations)

Down-regulated

Effects on chewing / sucking herbivores

Schweiger, Heise, Persicke, Müller - Chemical Ecology - Bielefeld University, Germany

Daily application of phytohormones 0.5 mM (150 pmol)

Heliothis virescens

Effects of phytohormone-treatmentson survival of chewing herbivore

Kaplan-Meier, log-rank tests + Bonferroni , N = 10

Schweiger, Heise, Persicke, Müller - Chemical Ecology - Bielefeld University, Germany

X - censoring

• Negative impact of both JA and SA• Attenuation of negative effects when hormones applied simultaneously

Myzus persicae

• Negative impact of JA and SA on herbivores of both feeding types• Intermediate survival on plants treated with both phytohormones

Effects of phytohormone-treatmentson survival of sucking herbivore

Schweiger, Heise, Persicke, Müller - Chemical Ecology - Bielefeld University, Germany

X - censoring

Kaplan-Meier, log-rank tests + Bonferroni , N = 10

Summary• Responses of Plantago lanceolata are highly treatment-specific

• Complementary, synergistic and antagonistic phytohormone effects fine-tune the plant metabolome

-

• Partial attenuation of effects when hormones applied together → strong interactions between both phytohormone pathways

Schweiger, Heise, Persicke, Müller - Chemical Ecology - Bielefeld University, Germany

• Herbivores of both feeding types negatively affected by both phytohormones when applied individually → complementary effects of the hormones

Schweiger et al. (2014) Plant Cell Environ 37: 1574-1585

Thanks Chemical Ecology group, Bielefeld University

Karsten Niehaus, CeBiTec, Bielefeld University

Effects of phytohormone-treatmentson population dynamics of aphids

Schweiger, Heise, Persicke, Müller - Chemical Ecology - Bielefeld University, Germany

Start: N = 10 x 10 adults

• negative impact of JA and SA on population growth

Schweiger, Heise, Persicke, Müller - Chemical Ecology - Bielefeld University, Germany

Start: N = 10 x 10 adults

Effects of phytohormone-treatmentson population dynamics of aphids

partial attenuation of negative effects when hormones applied simultaneously

→ No induction of iridoid glycosides

Schweiger, Heise, Persicke, Müller - Chemical Ecology - Bielefeld University, Germany

Kruskal-Wallis test, X² = 8.254, df = 4, P = 0.935, N = 10

Effects of phytohormones on target compoundsafter 72 h (2 treatments)

JA/SA pathway crosstalk

Adapted from Pieterse et al. (2009) Nat Chem Biol