The calmodulin-binding transcription factor SIGNAL RESPONSIVE1 is a novel regulator of glucosinolate metabolism and herbivory tolerance in Arabidopsis

Plant Cell Physiol. 2012 Dec;53(12):2008-15. doi: 10.1093/pcp/pcs143. Epub 2012 Oct 16.

Abstract

The Arabidopsis Ca(2+)/calmodulin (CaM)-binding transcription factor SIGNAL RESPONSIVE1 (AtSR1/CAMTA3) was previously identified as a key negative regulator of plant immune responses. Here, we report a new role for AtSR1 as a critical component of plant defense against insect herbivory. Loss of AtSR1 function impairs tolerance to feeding by the generalist herbivore Trichoplusia ni as well as wound-induced jasmonate accumulation. The susceptibility of the atsr1 mutant is associated with decreased total glucosinolate (GS) levels. The two key herbivory deterrents, indol-3-ylmethyl (I3M) and 4-methylsulfinylbutyl (4MSOB), showed the most significant reductions in atsr1 plants. Further, changes in AtSR1 transcript levels led to altered expression of several genes involved in GS metabolism including IQD1, MYB51 and AtST5a. Overall, our results establish AtSR1 as an important component of plant resistance to insect herbivory as well as one of only three described proteins involved in Ca(2+)/CaM-dependent signaling to function in the regulation of GS metabolism, providing a novel avenue for future investigations of plant-insect interactions.

Publication types

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

MeSH terms

  • Animals
  • Arabidopsis / genetics
  • Arabidopsis / metabolism
  • Arabidopsis / physiology*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Calcium Signaling
  • Calmodulin / metabolism
  • Cyclopentanes / metabolism
  • Disease Resistance
  • Gene Expression Regulation, Plant
  • Glucosinolates / metabolism*
  • Herbivory
  • Moths / physiology*
  • Mutation
  • Oxylipins / metabolism
  • Plant Diseases / immunology*
  • Plant Diseases / parasitology
  • Plant Growth Regulators / metabolism
  • Plants, Genetically Modified
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism*
  • RNA, Plant / genetics
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • Wounds and Injuries

Substances

  • Arabidopsis Proteins
  • Calmodulin
  • Cyclopentanes
  • Glucosinolates
  • Oxylipins
  • Plant Growth Regulators
  • RNA, Plant
  • Transcription Factors
  • jasmonic acid
  • AtSR1 protein, Arabidopsis
  • Protein-Serine-Threonine Kinases