Integration of ethylene and jasmonic acid signaling pathways in the expression of maize defense protein mir1-CP

A. Ankala, D. S. Luthe, W. P. Williams, J. R. Wilkinson

Research output: Contribution to journalArticlepeer-review

33 Scopus citations

Abstract

In plants, ethylene and jasmonate control the defense responses to multiple stressors, including insect predation. Among the defense proteins known to be regulated by ethyl-ene is maize insect resistance 1-cysteine protease (Mir1-CP). This protein is constitutively expressed in the insect-resistant maize (Zea mays) genotype Mp708; however, its abundance significantly increases during fall armyworm (Spodoptera frugiperda) herbivory. Within 1 h of herbivory by fall army-worm, Mir1-CP accumulates at the feeding site and continues to increase in abundance until 24 h without any increase in its transcript (mir1) levels. To resolve this discrepancy and elucidate the role of ethylene and jasmonate in the signaling of Mir1-CP expression, the effects of phytohormone biosynthesis and perception inhibitors on Mir1-CP expression were tested. Immunoblot analysis of Mir1-CP accumulation and quantitative reverse-transcriptase polymerase chain reaction examination of mir1 levels in these treated plants demonstrate that Mir1-CP accumulation is regulated by both transcript abundance and protein expression levels. The results also suggest that jasmonate functions upstream of ethylene in the Mir1-CP expression pathway, allowing for both low- level constitutive expression and a two-stage defensive response, an immediate response involving Mir1-CP accumulation and a delayed response inducing mir1 transcript expression.

Original languageEnglish (US)
Pages (from-to)1555-1564
Number of pages10
JournalMolecular Plant-Microbe Interactions
Volume22
Issue number12
DOIs
StatePublished - Dec 2009

All Science Journal Classification (ASJC) codes

  • Physiology
  • Agronomy and Crop Science

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