| Title: | Silencing an N-acyltransferase-like involved in lignin biosynthesis in Nicotiana attenuata dramatically alters herbivory-induced phenolamide metabolism |
| Author(s): | Gaquerel E; Kotkar H; Onkokesung N; Galis I; Baldwin IT; |
| Address: | "Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Jena, Germany. egaquerel@ice.mpg.de" |
| DOI: | 10.1371/journal.pone.0062336 |
| ISSN/ISBN: | 1932-6203 (Electronic) 1932-6203 (Linking) |
| Abstract: | "In a transcriptomic screen of Manduca sexta-induced N-acyltransferases in leaves of Nicotiana attenuata, we identified an N-acyltransferase gene sharing a high similarity with the tobacco lignin-biosynthetic hydroxycinnamoyl-CoA:shikimate/quinate hydroxycinnamoyl transferase (HCT) gene whose expression is controlled by MYB8, a transcription factor that regulates the production of phenylpropanoid polyamine conjugates (phenolamides, PAs). To evaluate the involvement of this HCT-like gene in lignin production as well as the resulting crosstalk with PA metabolism during insect herbivory, we transiently silenced (by VIGs) the expression of this gene and performed non-targeted (UHPLC-ESI/TOF-MS) metabolomics analyses. In agreement with a conserved function of N. attenuata HCT-like in lignin biogenesis, HCT-silenced plants developed weak, soft stems with greatly reduced lignin contents. Metabolic profiling demonstrated large shifts (up to 12% deregulation in total extracted ions in insect-attacked leaves) due to a large diversion of activated coumaric acid units into the production of developmentally and herbivory-induced coumaroyl-containing PAs (N',N''-dicoumaroylspermidine, N',N''-coumaroylputrescine, etc) and to minor increases in the most abundant free phenolics (chlorogenic and cryptochlorogenic acids), all without altering the production of well characterized herbivory-responsive caffeoyl- and feruloyl-based putrescine and spermidine PAs. These data are consistent with a strong metabolic tension, exacerbated during herbivory, over the allocation of coumaroyl-CoA units among lignin and unusual coumaroyl-containing PAs, and rule out a role for HCT-LIKE in tuning the herbivory-induced accumulation of other PAs. Additionally, these results are consistent with a role for lignification as an induced anti-herbivore defense" |
| Keywords: | "Acyltransferases/*genetics Amides/chemistry/*metabolism Animals Coumaric Acids/chemistry/metabolism *Gene Silencing Herbivory/*physiology Lignin/*biosynthesis Manduca/physiology Mass Spectrometry Models, Biological Nicotine/metabolism Phenols/chemistry/*m;" |
| Notes: | "MedlineGaquerel, Emmanuel Kotkar, Hemlata Onkokesung, Nawaporn Galis, Ivan Baldwin, Ian T eng Research Support, Non-U.S. Gov't 2013/05/25 PLoS One. 2013 May 21; 8(5):e62336. doi: 10.1371/journal.pone.0062336. Print 2013" |
