Background: Anthocyanins contribute to coloration and antioxidation effects in different plant tissues. MYB transcription factors have been demonstrated to be a key regulator for anthocyanin synthesis in many plants. However, little information was available about the MYB genes in the halophyte species Eutrema salsugineum. Result: Here we report the identification of an important anthocyanin biosynthesis regulator EsMYB90 from Eutrema salsugineum, which is a halophyte tolerant to multiple abiotic stresses. Our phylogenetic and localization analyses supported that EsMYB90 is an R2R3 type of MYB transcription factor. Ectopic expression of EsMYB90 in tobacco and Arabidopsis enhanced pigmentation and anthocyanin accumulation in various organs. The transcriptome analysis revealed that 42 genes upregulated by EsMYB90 in 35S:EsMYB90 tobacco transgenic plants are required for anthocyanin biosynthesis. Moreover, our qRT-PCR results showed that EsMYB90 promoted expression of early (PAL, CHS, and CHI) and late (DFR, ANS, and UFGT) anthocyanin biosynthesis genes in stems, leaves, and flowers of 35S:EsMYB90 tobacco transgenic plants. Conclusions: Our results indicated that EsMYB90 is a MYB transcription factor, which regulates anthocyanin biosynthesis genes to control anthocyanin biosynthesis. Our work provides a new tool to enhance anthocyanin production in various plants.

Flavonoids are representative secondary metabolites with different metabolic functions in plants. Previous study found that ectopic expression of EsMYB90 from Eutrema salsugineum could strongly increase anthocyanin content in transgenic tobacco via regulating the expression of anthocyanin biosynthesis genes. In the present research, metabolome analysis showed that there existed 130 significantly differential metabolites, of which 23 metabolites enhanced more than 1000 times in EsMYB90 transgenic tobacco leaves relative to the control, and the top 10 of the increased metabolites included caffeic acid, cyanidin O-syringic acid, myricetin and naringin. A total of 50 markedly differential flavonoids including flavones (14), flavonols (13), flavone C-glycosides (9), flavanones (7), catechin derivatives (5), anthocyanins (1) and isoflavone (1) were identified, of which 46 metabolites were at a significantly enhanced level. Integrated analysis of metabolome and transcriptome revealed that ectopic expression of EsMYB90 in transgenic tobacco leaves is highly associated with the prominent up-regulation of 16 flavonoid metabolites and the corresponding 42 flavonoid biosynthesis structure genes in phenylpropanoid/flavonoid pathways. Dual luciferase assay documented that EsMYB90 strongly activated the transcription of NtANS and NtDFR genes via improving their promoter activity in transiently expressed tobacco leaves, suggesting that EsMYB90 functions as a key regulator on anthocyanin and flavonoid biosynthesis. Taken together, the crucial regulatory role of EsMYB90 on enhancing many flavonoid metabolite levels is clearly demonstrated via modulating flavonoid biosynthesis gene expression in the leaves of transgenic tobacco, which extends our understanding of the regulating mechanism of MYB transcription factor in the phenylpropanoid/flavonoid pathways and provides a new clue and tool for further investigation and genetic engineering of flavonoid metabolism in plants.

Background: Anthocyanins contribute to coloration and antioxidation effects in different plant tissues. MYB transcription factors have been demonstrated to be a key regulator for anthocyanin synthesis in many plants. However, little information was available about the MYB genes in the halophyte species Eutrema salsugineum.Result: Here we report the identification of an important anthocyanin biosynthesis regulator EsMYB90 from Eutrema salsugineum, which is a halophyte tolerant to multiple abiotic stresses. Our phylogenetic and localization analyses supported that EsMYB90 is an R2R3 type of MYB transcription factor. Ectopic expression of EsMYB90 in tobacco and Arabidopsis enhanced pigmentation and anthocyanin accumulation in various organs. The transcriptome analysis revealed that 42 genes upregulated by EsMYB90 in 35S:EsMYB90 tobacco transgenic plants are required for anthocyanin biosynthesis. Moreover, our qRT-PCR results showed that EsMYB90 promoted expression of early (PAL, CHS, and CHI) and late (DFR, ANS, and UFGT) anthocyanin biosynthesis genes in stems, leaves, and flowers of 35S:EsMYB90 tobacco transgenic plants.Conclusions: Our results indicated that EsMYB90 is a MYB transcription factor, which regulates anthocyanin biosynthesis genes to control anthocyanin biosynthesis. Our work provides a new tool to enhance anthocyanin production in various plants.

Background: Anthocyanins contribute to coloration and antioxidation effects in different plant tissues. MYB transcription factors have been demonstrated to be a key regulator for anthocyanin synthesis in many plants. However, little information was available about the MYB genes in the halophyte species Eutrema salsugineum . Result: Here we report the identification of an important anthocyanin biosynthesis regulator Es MYB90 from Eutrema salsugineum , which is a halophyte tolerant to multiple abiotic stresses. Our phylogenetic and localization analyses supported that Es MYB90 is an R2R3 type of MYB transcription factor. Ectopic expression of EsMYB90 in tobacco and Arabidopsis enhanced pigmentation and anthocyanin accumulation in various organs. The transcriptome analysis revealed that 42 genes upregulated by Es MYB90 in 35S : EsMYB90 tobacco transgenic plants are required for anthocyanin biosynthesis. Moreover, our qRT-PCR results showed that Es MYB90 promoted expression of early ( PAL , CHS , and CHI ) and late ( DFR , ANS , and UFGT ) anthocyanin biosynthesis genes in stems, leaves, and flowers of 35S : EsMYB90 tobacco transgenic plants. Conclusions: Our results indicated that Es MYB90 is a MYB transcription factor, which regulates anthocyanin biosynthesis genes to control anthocyanin biosynthesis. Our work provides a new tool to enhance anthocyanin production in various plants. Keywords : Anthocyanin, flavonoid, Eutrema salsugineum , R2R3 MYB transcription factor, Es MYB90, transcriptional regulation, anthocyanin biosynthesis genes.

Background: Anthocyanins contribute to coloration and antioxidation effects in different plant tissues. MYB transcription factors have been demonstrated to be a key regulator for anthocyanin synthesis in many plants. However, little information was available about the MYB genes in the halophyte species Eutrema salsugineum.Result: Here we report the identification of an important anthocyanin biosynthesis regulator EsMYB90 from Eutrema salsugineum, which is a halophyte tolerant to multiple abiotic stresses. Our phylogenetic and localization analyses supported that EsMYB90 is an R2R3 type of MYB transcription factor. Ectopic expression of EsMYB90 in tobacco and Arabidopsis enhanced pigmentation and anthocyanin accumulation in various organs. The transcriptome analysis revealed that 42 genes upregulated by EsMYB90 in 35S:EsMYB90 tobacco transgenic plants are required for anthocyanin biosynthesis. Moreover, our qRT-PCR results showed that EsMYB90 promoted expression of early (PAL, CHS, and CHI) and late (DFR, ANS, and UFGT) anthocyanin biosynthesis genes in stems, leaves, and flowers of 35S:EsMYB90 tobacco transgenic plants. Conclusions:Our results indicated that EsMYB90 is a MYB transcription factor, which regulates anthocyanin biosynthesis genes to control anthocyanin biosynthesis. Our work provides a new tool to enhance anthocyanin production in various plants. BackgroundFlavonoids which are derivatives of the phenylpropanoid/flavonoid pathway mainly contain proanthocyanidins (PAs), anthocyanins and flavonols [1][2][3]. As important pigments, anthocyanins are responsible for red, purple, violet and blue colors in flowers, fruits, and leaves, which determine economic traits of crops and ornamental plants [4][5][6][7]. Anthocyanins are the end products of a specific branch in the phenylpropanoid/flavonoid biosynthesis pathway. Enzymes involved in anthocyanin biosynthesis have been extensively studied in many plant species [8]. Catalyzed by phenylalanine ammonia-lyase (PAL), the initial step of the flavonoid pathway is the conversion of phenylalanine into trans-cinnamic acid [9], while chalcone synthase (CHS) catalyzes the first committed step in the flavonoid biosynthesis to form naringenin chalcone. Chalcone isomerase (CHI) cyclizes chalcone to 4 form naringenin [8]. The naringenin is then converted into dihydrokaempferol (DHK) by flavanone 3 βhydroxylase (F3H). DHK is further hydroxylated to dihydroquercetin (DHQ) by flavonoid 3 'hydroxylase (F3'H), or to dihydromyricetin (DHM) by flavonoid 3',5'-hydroxylase (F3'5'H). Dihydroflavonol 4-reductase (DFR) converts DHQ into leucocyanidin, which is further converted into anthocyanidins by anthocyanidin synthase (ANS). Finally, UDP-glucose: flavonoid 3-Oglucosyltranferase (UFGT) catalyzes glycosylation of anthocyanidins to form anthocyanins [8,10-12]. MYB transcription factors play a central role in regulating expression of genes encoding major enzymes for anthocyanin biosynthesis via forming the transcriptional complex containing MYB-bHLH-WD40 (MBW) [1,13-15]. Expression...

Background: Anthocyanins contribute to coloration and antioxidation effects in different plant tissues. MYB transcription factors have been demonstrated to be a key regulator for anthocyanin synthesis in many plants. However, little information was available about the MYB genes in the halophyte species Eutrema salsugineum . Result: Here we report the identification of an important anthocyanin biosynthesis regulator Es MYB90 from Eutrema salsugineum , which is a halophyte tolerant to multiple abiotic stresses. Our phylogenetic and localization analyses supported that Es MYB90 is an R2R3 type of MYB transcription factor. Ectopic expression of EsMYB90 in tobacco and Arabidopsis enhanced pigmentation and anthocyanin accumulation in various organs. The transcriptome analysis revealed that 42 genes upregulated by Es MYB90 in 35S : EsMYB90 tobacco transgenic plants are required for anthocyanin biosynthesis. Moreover, our qRT-PCR results showed that Es MYB90 promoted expression of early ( PAL , CHS , and CHI ) and late ( DFR , ANS , and UFGT ) anthocyanin biosynthesis genes in stems, leaves, and flowers of 35S : EsMYB90 tobacco transgenic plants. Conclusions: Our results indicated that Es MYB90 is a MYB transcription factor, which regulates anthocyanin biosynthesis genes to control anthocyanin biosynthesis. Our work provides a new tool to enhance anthocyanin production in various plants.

Background: Anthocyanins contribute to coloration and antioxidation effects in different plant tissues. MYB transcription factors have been demonstrated to be a key regulator for anthocyanin synthesis in many plants. However, little information was available about the MYB genes in the halophyte species Eutrema salsugineum.Result: Here we report the identification of an important anthocyanin biosynthesis regulator EsMYB90 from Eutrema salsugineum, which is a halophyte tolerant to multiple abiotic stresses. Our phylogenetic and localization analyses supported that EsMYB90 is an R2R3 type of MYB transcription factor. Ectopic expression of EsMYB90 in tobacco and Arabidopsis enhanced pigmentation and anthocyanin accumulation in various organs. The transcriptome analysis revealed that 42 genes upregulated by EsMYB90 in 35S:EsMYB90 tobacco transgenic plants are required for anthocyanin biosynthesis. Moreover, our qRT-PCR results showed that EsMYB90 promoted expression of early (PAL, CHS, and CHI) and late (DFR, ANS, and UFGT) anthocyanin biosynthesis genes in stems, leaves, and flowers of 35S:EsMYB90 tobacco transgenic plants.Conclusions: Our results indicated that EsMYB90 is a novel MYB transcription factor, which regulates anthocyanin biosynthesis genes to control anthocyanin biosynthesis. Our work provides a new tool to enhance anthocyanin production in various plants.

Background: Anthocyanins contribute to coloration and antioxidation effects in different plant tissues. MYB transcription factors have been demonstrated to be a key regulator for anthocyanin synthesis in many plants. However, little information was available about the MYB genes in the halophyte species Eutrema salsugineum . Result: Here we report the identification of an important anthocyanin biosynthesis regulator Es MYB90 from Eutrema salsugineum , which is a halophyte tolerant to multiple abiotic stresses. Our phylogenetic and localization analyses supported that Es MYB90 is an R2R3 type of MYB transcription factor. Ectopic expression of EsMYB90 in tobacco and Arabidopsis enhanced pigmentation and anthocyanin accumulation in various organs. The transcriptome analysis revealed that 42 genes upregulated by Es MYB90 in 35S : EsMYB90 tobacco transgenic plants are required for anthocyanin biosynthesis. Moreover, our qRT-PCR results showed that Es MYB90 promoted expression of early ( PAL , CHS , and CHI ) and late ( DFR , ANS , and UFGT ) anthocyanin biosynthesis genes in stems, leaves, and flowers of 35S : EsMYB90 tobacco transgenic plants. Conclusions: Our results indicated that Es MYB90 is a MYB transcription factor, which regulates anthocyanin biosynthesis genes to control anthocyanin biosynthesis. Our work provides a new tool to enhance anthocyanin production in various plants. Keywords : Anthocyanin, flavonoid, Eutrema salsugineum , R2R3 MYB transcription factor, Es MYB90, transcriptional regulation, anthocyanin biosynthesis genes.