title: Methyl jasmonate and yeast elicitor induce differential transcriptional and metabolic re-programming in cell suspension cultures of the model legume Medicago truncatula.
abstract: Exposure of cell suspension cultures of Medicago truncatula Gaerth. to methyl jasmonate (MeJA) resulted in up to 50-fold induction of transcripts encoding the key triterpene biosynthetic enzyme beta-amyrin synthase (betaAS; EC 5.4.99.-). Transcripts reached maximum levels at 24 h post-elicitation with 0.5 mM MeJA. The entry point enzymes into the phenylpropanoid and flavonoid pathways, L: -phenylalanine ammonia-lyase (PAL; EC 4.3.1.5) and chalcone synthase (CHS; EC 2.3.1.74), respectively, were not induced by MeJA. In contrast, exposure of cells to yeast elicitor (YE) resulted in up to 45- and 14-fold induction of PAL and CHS transcripts, respectively, at only 2 h post-elicitation. betaAS transcripts were weakly induced at 12 h after exposure to YE. Over 30 different triterpene saponins were identified in the cultures, many of which were strongly induced by MeJA, but not by YE. In contrast, cinnamic acids, benzoic acids and isoflavone-derived compounds accumulated following exposure of cultures to YE, but few changes in phenylpropanoid levels were observed in response to MeJA. DNA microarray analysis confirmed the strong differential transcriptional re-programming of the cell cultures for multiple genes in the phenylpropanoid and triterpene pathways in response to MeJA and YE, and indicated different responses of individual members of gene families. This work establishes Medicago cell cultures as an excellent model for future genomics approaches to understand the regulation of legume secondary metabolism.
authors.affiliation: Plant Biology Division, Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK 73401, USA.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Suzuki
authors.forename: M S Srinivasa
authors.initials: MS
authors.lastname: Reddy
authors.forename: Marina
authors.initials: M
authors.lastname: Naoumkina
authors.forename: Naveed
authors.initials: N
authors.lastname: Aziz
authors.forename: Gregory D
authors.initials: GD
authors.lastname: May
authors.forename: David V
authors.initials: DV
authors.lastname: Huhman
authors.forename: Lloyd W
authors.initials: LW
authors.lastname: Sumner
authors.forename: Jack W
authors.initials: JW
authors.lastname: Blount
authors.forename: Pedro
authors.initials: P
authors.lastname: Mendes
authors.forename: Richard A
authors.initials: RA
authors.lastname: Dixon
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D000085:Acetates / Q000494:pharmacology*; D000217:Acyltransferases / Q000096:biosynthesis; D002478:Cells, Cultured; D003517:Cyclopentanes / Q000494:pharmacology*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D019751:Intramolecular Transferases / Q000096:biosynthesis; D046913:Medicago truncatula / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D054883:Oxylipins; D010650:Phenylalanine Ammonia-Lyase / Q000096:biosynthesis; D010937:Plant Growth Regulators / Q000494:pharmacology*; D012441:Saccharomyces cerevisiae; D020156:Salicylic Acid / Q000494:pharmacology; D012503:Saponins / Q000096:biosynthesis; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D000085:Acetates; D003517:Cyclopentanes; D054883:Oxylipins; D010937:Plant Growth Regulators; D012503:Saponins; D000040:Abscisic Acid; C072239:methyl jasmonate; D000217:Acyltransferases; C020141:flavanone synthetase; D010650:Phenylalanine Ammonia-Lyase; D019751:Intramolecular Transferases; C039924:2,3-oxidosqualene-beta-amyrin-cyclase; D020156:Salicylic Acid