Characterization of Stilbene Synthase Genes in Mulberry (<i>Morus atropurpurea</i>) and Metabolic Engineering for the Production of Resveratrol in <i>Escherichia coli</i>

Stilbenes have been recognized for their beneficial physiological effects on human health. Stilbene synthase (STS) is the key enzyme of resveratrol biosynthesis and has been studied in numerous plants. Here, four <i>MaSTS</i> genes were isolated and identified in mulberry (<i>Morus atropurpurea</i> Roxb.). The expression levels of <i>MaSTS</i> genes and the accumulation of <i>trans</i>-resveratrol, <i>trans</i>-oxyresveratrol, and <i>trans</i>-mulberroside A were investigated in different plant organs. A novel coexpression system that harbored 4-coumarate:CoA ligase gene (<i>Ma4CL</i>) and <i>MaSTS</i> was established. Stress tests suggested that <i>MaSTS</i> genes participate in responses to salicylic acid, abscisic acid, wounding, and NaCl stresses. Additionally, overexpressed <i>MaSTS</i> in transgenic tobacco elevated the <i>trans</i>-resveratrol level and increased tolerance to drought and salinity stresses. These results revealed the major <i>MaSTS</i> gene, and we evaluated its function in mulberry, laying the foundation for future research on stilbene metabolic pathways in mulberry

Primers used for qRT-PCR in <i>Morus atropurpurea</i> cv. <i>Jialing</i> No.40.

<p>Primers used for qRT-PCR in <i>Morus atropurpurea</i> cv. <i>Jialing</i> No.40.</p

Information of genes involved in ethylene signaling in <i>Morus notabilis</i>.

<p>^a The CDS length was predicted according to the predicted <i>Morus</i> genes.</p><p>^b The number of exon was predicted based on the <i>Morus</i> genomic data.</p><p>Information of genes involved in ethylene signaling in <i>Morus notabilis</i>.</p

Changes in ethylene production, SSC and firmness during fruit development of <i>Morus atropurpurea</i> cv. <i>Jialing</i> No.40.

<p>(A) <i>Morus</i> fruit during development. (B) The ethylene production, SSC and firmness. The batch 1 fruits were used for these experiments. Error bars on each column indicate SDs from eight replicates.</p

The expression profiles of genes involved in ethylene signal transduction in <i>Morus notabilis</i>.

<p>Expression analysis of genes involved in ethylene signal transduction based on the RPKM (reads per kilobase of exon model per million mapped reads) profile of five tissues (root, bark, bud, flower, and leaf). Cluster 3.0 software was used to normalize the expression level of the ethylene signal-related genes from RNA sequencing data. Sample names are shown above the heat maps. Color scale indicates the degree of expression: green, low expression; red, high expression; grey, no expression.</p

Gene structure and predicted functional domains of <i>Morus notabilis</i> ethylene signaling genes.

<p>Gene structures were obtained by aligning the cloned cDNA sequences with the <i>M</i>. <i>notabilis</i> genome data and functional domains were predicted in SMART (<a href="http://smart.embl-heidelberg.de/smart/set_mode.cgi?NORMAL=1" target="_blank">http://smart.embl-heidelberg.de/smart/set_mode.cgi?NORMAL=1</a>). Gene structures were displayed by Fancy Gene (<a href="http://bio.ieo.eu/fancygene/" target="_blank">http://bio.ieo.eu/fancygene/</a>)</p

Effects of exogenous C₂H₄ and 1-MCP on postharvest fruit of <i>Morus atropurpurea</i> cv. <i>Jialing</i> No.40 at 23°C.

<p>The batch 2 fruits were divided into three groups. Two groups were treated with ethylene and 1-MCP, respectively. The third group of fruits was sealed in a similar container of the same volume as a control. Error bars on each column indicate SDs from eight replicates.</p

Primers used for cloning the genes involved in the ethylene signal transduction in <i>Morus atropurpurea</i> cv. <i>Jialing</i> No.40.

<p>Primers used for cloning the genes involved in the ethylene signal transduction in <i>Morus atropurpurea</i> cv. <i>Jialing</i> No.40.</p

Expression of the genes involved in ethylene biosynthesis and signaling pathway during fruit ripening of <i>Morus atropurpurea</i> cv. <i>Jialing</i> No.40.

<p>The batch 2 fruits were used for qRT-PCR. Error bars on each column indicate SDs from three replicates. Significant differences (<i>P</i><0.05) among treatment are marked with different letters above bars.</p

Expression of different components of the ethylene signaling pathway during fruit development of <i>Morus atropurpurea</i> cv. <i>Jialing</i> No.40.

<p>The batch 1 fruits were used for qRT-PCR. Each column height indicates relative mRNA abundance. Error bars on each column indicate SDs from three replicates. Significant differences (<i>P</i><0.05) are marked with different letters above bars.</p