A novel R2R3 MYB transcription factor NtMYBJS1 is a methyl jasmonate‐dependent regulator of phenylpropanoid‐conjugate biosynthesis in tobacco

Abstract

SummaryTarget metabolic and large-scale transcriptomic analyses of tobacco (Nicotiana tabacum L.) Bright Yellow-2 (BY-2) cells were employed to identify novel gene(s) involved in methyl jasmonate (MJ)-dependent function in plants. At the metabolic level, we describe the specific accumulation of several phenylpropanoid-polyamine conjugates in MJ-treated BY-2 cells. Furthermore, global gene expression analysis of MJ-treated cells using a 16K cDNA microarray containing expressed sequence tags (ESTs) from BY-2 cells revealed 828 genes that were upregulated by MJ treatment within 48 h. Using time-course expression data we identified a novel MJinducible R2R3 MYB-type transcription factor (NtMYBJS1) that was co-expressed in a close temporal pattern with the core phenylpropanoid genes phenylalanine ammonia-lyase (PAL) and 4-coumarate:CoA ligase (4CL). Overexpression of NtMYBJS1 in tobacco BY-2 cells caused accumulation of specific phenylpropanoid conjugates in the cells. Subsequent microarray analysis of NtMYBJS1 transgenic lines revealed that a limited number of genes, including PAL and 4CL, were specifically induced in the presence of the NtMYBJS1 transgene. These results, together with results of both antisense expression analysis and of gel mobility shift assays, strongly indicate that the NtMYBJS1 protein functions in tobacco MJ signal transduction, inducing phenylpropanoid biosynthetic genes and the accumulation of phenylpropanoid-polyamine conjugates during stress.

The R2R3-MYB Transcription Factors MYB14 and MYB15 Regulate Stilbene Biosynthesis in Vitis vinifera

“…This domain, designated as SG2 DxSFW-MxFWFD (see Supplemental Figure 2A, Supplemental Methods 1, and Supplemental References 1 online) appears to be associated with stress responses in Arabidopsis (Stracke et al, 2001). Indeed, all of the Arabidopsis, tobacco, and carrot TFs belonging to the Vv-MYB14/15 cluster have been shown to respond to abiotic stresses (Maeda et al, 2005;Chen et al, 2006;Gális et al, 2006). Interestingly, homologous MYB-factors from other stilbene-producing plants, such as Poaceae (Sb_06g022660, Sb_04g026480, and Sb_01g019270) and Pinaceae (Pg-MYB11 and Pg-MYB12), have been identified and also cluster with Vv-MYB14/MYB15 (see Supplemental Figure 2A, Supplemental Methods 1, and Supplemental References 1 online).…”

“…Nt-LBM2, Nt-MYBJS1, and Dc-MYB1 have also been shown to be involved in regulating upstream genes in the core PP pathway, such as PAL and C4H (Sugimoto et al, 2000;Gális et al, 2006), which are key genes in the production of p-coumaroyl-CoA, the main substrate for flavonoid and stilbene biosynthesis. Grapevine hairy roots ectopically expressing Vv-MYB15 showed a marked increase in the expression of Vv-PAL ( Figure 5A).…”

Transcription Factors of Lotus: Regulation of Isoflavonoid Biosynthesis Requires Coordinated Changes in Transcription Factor Activity

“…The expression of R2R3MYB subgroup 2 genes in other species is known to be induced in response to biotic and abiotic stress, and some subgroup 2 TFs have been shown to bind to the promoters of genes encoding enzymes of the GPP (PAL [Sugimoto et al, 2000;Maeda et al, 2005] and 4CL [Gális et al, 2006]). Generally, these TFs are thought to induce shikimate and phenylpropanoid metabolism in response to stress (Chen et al, 2006;Ding et al, 2009).…”

Mapping methyl jasmonate-mediated transcriptional reprogramming of metabolism and cell cycle progression in cultured Arabidopsis cells

“…Combined transcript and metabolite profiling approaches to tackle the MeJA-mediated regulation of secondary metabolism resulted in the establishment of gene-to-metabolite networks involved in the biosynthesis of the pharmaceutically valuable terpenoid indole alkaloids in periwinkle (Catharanthus roseus) cells (7), in the characterization of enzymatic steps in the isoflavone and triterpene biosynthetic pathways in barrel medic (Medicago truncatula) cells (8,9), and in the isolation of novel regulators of nicotine and phenylpropanoid conjugate biosynthesis in tobacco (Nicotiana tabacum) cells (10)(11)(12)(13) or of aliphatic glucosinolate biosynthesis in Arabidopsis thaliana cells (14).…”