A HFD (D12451); Resv, mice fed a HFD supplemented with resveratrol; DJ, mice fed a HFD in which the corn starch and sucrose were replaced with Dongjin rice; RS18-half, mice fed a HFD in which half of the corn starch and sucrose were replaced 22948146 with the resveratrol-enriched rice; RS18, mice fed a HFD in which the corn starch and sucrose were replaced with the resveratrol-enriched rice. Values in a column with a superscripted letter indicate statistical significance as analyzed by an unpaired Student’s t-test; a p,0.05 compared with CTL; b p,0.01 compared with CTL; c p,0.05 compared with DJ; d p,0.01 compared with DJ. doi:10.1371/journal.pone.0057930.tThe 4CL enzyme converts p-coumaric acid into coumaroyl-CoA by coupling it with coenzyme A. Subsequently, three malonyl-CoA units are 
added to coumaroyl-CoA by STS with a loss of carbon dioxide, which results in the production of resveratrol [9,10]. AhSTS1 was amplified from cDNA using the specific primers 59GGATCCATGGTGTCTGTGAGTG-39 and 59-CTCGAGTATGGCCACACTGCGGAG-39. The At4CL2 gene (GenBank accession no. NM113019) was also amplified using RT-PCR from Arabidopsis leaf RNA using the gene-specific primers 59-GGATCCATGACGACACAAGATGTGATAG-39 and 59CTCGAGGTTCATTAATCC ATTTGCTAGT-39 (the substitutions required to create BamHI and XhoI restriction sites are underlined). The amplified fragments of AhSTS1 and At4CL2 were P7C3 biological activity cloned into pET28a, a Acid Yellow 23 biological activity plasmid carrying a kanamycin resistance marker, and the pMAL-c2x vector, which harbors an ampicillin marker. The AhSTS1 and At4CL2 coding sequences were inserted in frame with the His and MBP (maltose-binding protein) carboxyl terminal tags, respectively. The plasmids containing each AhSTS1 and At4CL2 gene were cotransformed into BL21 E. coli for the induction of protein expression [27]. Finally, E. coli cells carrying the resistance genes for kanamycin and ampicillin were selected. The cells were grown in LB supplemented with 100 mg/mL of kanamycin and ampicillin at 37uC. Protein expression was induced at OD600 = 0.5 by adding 1 mM isopropyl b-Dthiogalactopyranoside (IPTG). After 24 and 48 h, the cells were harvested by centrifugation and resuspended in lysis buffer (50 mM NaH2PO4, 300 mM NaCl, and 10 mM imidazole). After sonication, the samples were subjected to SDS-PAGE for western blot analysis. To examine resveratrol production using the recombinant proteins, E. coli cells carrying both genes were grown in 2XYT medium (10 g/L yeast extract, 16 g/L tryptone, 5 g/L NaCl) supplemented with 5 mM p-coumaric acid (C9008, Sigma) and 0.1 mM IPTG at 28uC. After 48 h of incubation, 1 mL of the culture medium was centrifuged at 13,000 rpm for 15 min. The supernatant was transferred to a new tube, and 50 mL 1 N hydrochloric acid was added to adjust the pH to 9.0. These samples were stored overnight at 220uC. The tubes were thawed at room temperature, and resveratrol was isolated with two extractions of equal volumes of ethyl acetate, dried under nitrogen gas, and then resuspended in 100 mL of methanol. All of the samples were stored at 220uC until they were used for the resveratrol content analysis [10,28].Binary Vector Construction and Rice TransformationTo overexpress AhSTS1 in rice, the binary vector pSB22 was constructed by inserting an expression cassette encoding the maize Ubi1 promoter [13], multiple cloning sites (BamHI, SmaI, and SacI), and the nopaline synthase (Nos) terminator into the HindIII and EcoRI sites of the pCAMBIA3300 vector carrying the herbicide r.A HFD (D12451); Resv, mice fed a HFD supplemented with resveratrol; DJ, mice fed a HFD in which the corn starch and sucrose were replaced with Dongjin rice; RS18-half, mice fed a HFD in which half of the corn starch and sucrose were replaced 22948146 with the resveratrol-enriched rice; RS18, mice fed a HFD in which the corn starch and sucrose were replaced with the resveratrol-enriched rice. Values in a column with a superscripted letter indicate statistical significance as analyzed by an unpaired Student’s t-test; a p,0.05 compared with CTL; b p,0.01 compared with CTL; c p,0.05 compared with DJ; d p,0.01 compared with DJ. doi:10.1371/journal.pone.0057930.tThe 4CL enzyme converts p-coumaric acid into coumaroyl-CoA by coupling it with coenzyme A. Subsequently, three malonyl-CoA units are added to coumaroyl-CoA by STS with a loss of carbon dioxide, which results in the production of resveratrol [9,10]. AhSTS1 was amplified from cDNA using the specific primers 59GGATCCATGGTGTCTGTGAGTG-39 and 59-CTCGAGTATGGCCACACTGCGGAG-39. The At4CL2 gene (GenBank accession no. NM113019) was also amplified using RT-PCR from Arabidopsis leaf RNA using the gene-specific primers 59-GGATCCATGACGACACAAGATGTGATAG-39 and 59CTCGAGGTTCATTAATCC ATTTGCTAGT-39 (the substitutions required to create BamHI and XhoI restriction sites are underlined). The amplified fragments of AhSTS1 and At4CL2 were cloned into pET28a, a plasmid carrying a kanamycin resistance marker, and the pMAL-c2x vector, which harbors an ampicillin marker. The AhSTS1 and At4CL2 coding sequences were inserted in frame with the His and MBP (maltose-binding protein) carboxyl terminal tags, respectively. The plasmids containing each AhSTS1 and At4CL2 gene were cotransformed into BL21 E. coli for the induction of protein expression [27]. Finally, E. coli cells carrying the resistance genes for kanamycin and ampicillin were selected. The cells were grown in LB supplemented with 100 mg/mL of kanamycin and ampicillin at 37uC. Protein expression was induced at OD600 = 0.5 by adding 1 mM isopropyl b-Dthiogalactopyranoside (IPTG). After 24 and 48 h, the cells were harvested by centrifugation and resuspended in lysis buffer (50 mM NaH2PO4, 300 mM NaCl, and 10 mM imidazole). After sonication, the samples were subjected to SDS-PAGE for western blot analysis. To examine resveratrol production using the recombinant proteins, E. coli cells carrying both genes were grown in 2XYT medium (10 g/L yeast extract, 16 g/L tryptone, 5 g/L NaCl) supplemented with 5 mM p-coumaric acid (C9008, Sigma) and 0.1 mM IPTG at 28uC. After 48 h of incubation, 1 mL of the culture medium was centrifuged at 13,000 rpm for 15 min. The supernatant was transferred to a new tube, and 50 mL 1 N hydrochloric acid was added to adjust the pH to 9.0. These samples were stored overnight at 220uC. The tubes were thawed at room temperature, and resveratrol was isolated with two extractions of equal volumes 
of ethyl acetate, dried under nitrogen gas, and then resuspended in 100 mL of methanol. All of the samples were stored at 220uC until they were used for the resveratrol content analysis [10,28].Binary Vector Construction and Rice TransformationTo overexpress AhSTS1 in rice, the binary vector pSB22 was constructed by inserting an expression cassette encoding the maize Ubi1 promoter [13], multiple cloning sites (BamHI, SmaI, and SacI), and the nopaline synthase (Nos) terminator into the HindIII and EcoRI sites of the pCAMBIA3300 vector carrying the herbicide r.