Oxylipins Other Than Jasmonic Acid Are Xylem-Resident Signals Regulating Systemic Resistance Induced by Trichoderma virens in Maize

Plant Cell. 2020 Jan;32(1):166-185. doi: 10.1105/tpc.19.00487. Epub 2019 Nov 4.


Multiple long-distance signals have been identified for pathogen-induced systemic acquired resistance, but mobile signals for symbiont-induced systemic resistance (ISR) are less well understood. We used ISR-positive and -negative mutants of maize (Zea mays) and the beneficial fungus Trichoderma virens and identified 12-oxo-phytodienoic acid (12-OPDA) and α-ketol of octadecadienoic acid (KODA) as important ISR signals. We show that a maize 13-lipoxygenase mutant, lox10, colonized by the wild-type T. virens (TvWT) lacked ISR response against Colletotrichum graminicola but instead displayed induced systemic susceptibility. Oxylipin profiling of xylem sap from T. virens-treated plants revealed that 12-OPDA and KODA levels correlated with ISR. Transfusing sap supplemented with 12-OPDA or KODA increased receiver plant resistance in a dose-dependent manner, with 12-OPDA restoring ISR of lox10 plants treated with TvWT or T. virens Δsm1, a mutant unable to induce ISR. Unexpectedly, jasmonic acid (JA) was not involved, as the JA-deficient opr7 opr8 mutant plants retained the capacity for T. virens-induced ISR. Transcriptome analysis of TvWT-treated maize B73 revealed upregulation of 12-OPDA biosynthesis and OPDA-responsive genes but downregulation of JA biosynthesis and JA response genes. We propose a model that differential regulation of 12-OPDA and JA in response to T. virens colonization results in ISR induction.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Cyclopentanes / metabolism*
  • Disease Resistance / physiology*
  • Fatty Acids, Unsaturated
  • Gene Expression Regulation, Plant
  • Isomerism
  • Lipoxygenase / genetics
  • Oxylipins / metabolism*
  • Plant Diseases / microbiology
  • Trichoderma / pathogenicity
  • Xylem / metabolism*
  • Zea mays / genetics
  • Zea mays / physiology*


  • Cyclopentanes
  • Fatty Acids, Unsaturated
  • Oxylipins
  • octadecadienoic acid
  • 12-oxophytodienoic acid
  • jasmonic acid
  • 13-lipoxygenase
  • Lipoxygenase