Methyl jasmonate and yeast elicitor induce differential transcriptional and metabolic re-programming in cell suspension cultures of the model legume Medicago truncatula.
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.
Suzuki
Hideyuki
H
Plant Biology Division, Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK 73401, USA.
Reddy
M S Srinivasa
MS
Naoumkina
Marina
M
Aziz
Naveed
N
May
Gregory D
GD
Huhman
David V
DV
Sumner
Lloyd W
LW
Blount
Jack W
JW
Mendes
Pedro
P
Dixon
Richard A
RA
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
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