RuBPCase activase (RCA) mediates growth-defense trade-offs: silencing RCA redirects jasmonic acid (JA) flux from JA-isoleucine to methyl jasmonate (MeJA) to attenuate induced defense responses in Nicotiana attenuata.
• RuBPCase activase (RCA), an abundant photosynthetic protein, is strongly down-regulated in response to Manduca sexta's oral secretion (OS) in Nicotiana attenuata. RCA-silenced plants are impaired not only in photosynthetic capacity and growth, but also in jasmonic acid-isoleucine (JA-Ile) signaling, and herbivore resistance mediated by JA-Ile-dependent defense traits. These responses are consistent with a resource-based growth-defense trade-off. • As JA + Ile supplementation of OS restored wild-type (WT) levels of JA-Ile, defenses and resistance to M. sexta, but OS supplemented individually with JA or Ile did not, the JA-Ile deficiency of RCA-silenced plants could not be attributed to lower JA or Ile pools or JAR4/6 conjugating activity. Similar levels of JA-Ile derivatives after OS elicitation indicated unaltered JA-Ile turnover, and lower levels of other JA conjugates ruled out competition from other conjugation reactions. • RCA-silenced plants accumulated more methyl jasmonate (MeJA) after OS elicitation, which corresponded to increased jasmonate methyltransferase (JMT) activity. RCA silencing phenocopies JMT overexpression, wherein elevated JMT activity redirects OS-elicited JA flux towards inactive MeJA, creating a JA sink which depletes JA-Ile and its associated defense responses. • Hence, RCA plays an additional non-photosynthetic role in attenuating JA-mediated defenses and their associated costs, potentially allowing plants to anticipate resource-based constraints on growth before they actually occur.
Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745, Jena, Germany.
Sirsha
S
Mitra
Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745, Jena, Germany.
Ian T
IT
Baldwin
D000085:Acetates / Q000378:metabolism*; D000818:Animals; D003517:Cyclopentanes / Q000378:metabolism* / Q000494:pharmacology; D020868:Gene Silencing / Q000187:drug effects; D060434:Herbivory / Q000187:drug effects; D007532:Isoleucine / Q000378:metabolism*; D018402:Manduca / Q000187:drug effects / Q000502:physiology; D008745:Methylation; D008780:Methyltransferases / Q000378:metabolism; D054883:Oxylipins / Q000378:metabolism* / Q000494:pharmacology; D010940:Plant Proteins / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D014026:Nicotiana / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development* / Q000276:immunology*
D000085:Acetates; D003517:Cyclopentanes; D054883:Oxylipins; D010940:Plant Proteins; C054765:rca protein, plant; D007532:Isoleucine; C011006:jasmonic acid; C072239:methyl jasmonate; D008780:Methyltransferases
Manduca sexta; Nicotiana attenuata; RuBPCase activase; herbivory; jasmonate methyl transferase; jasmonate signaling; methyl jasmonate; plant defense