Functional analysis of three BrMYB28 transcription factors controlling the biosynthesis of glucosinolates in Brassica rapa

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• 作者：Mi-Suk Seo ; Mina Jin ; Jin-Hyuk Chun ; Sun-Ju Kim ; Beom-Seok Park…
• 关键词：Brassica rapa ; Glucosinolates ; Transcription factor BrMYB28s ; Chinese cabbage ; Transgenic plats
• 刊名：Plant Molecular Biology
• 出版年：2016
• 出版时间：March 2016
• 年：2016
• 卷：90
• 期：4-5
• 页码：503-516
• 全文大小：1,413 KB
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Life Sciences<br>Plant Sciences<br>Biochemistry<br>Plant Pathology<br>
• 出版者：Springer Netherlands
• ISSN：1573-5028

文摘

Glucosinolates (GSLs) are secondary metabolites that have anticarcinogenic activity and play defense roles in plants of the Brassicaceae family. MYB28 is known as a transcription factor that regulates aliphatic GSL biosynthesis in Arabidopsis thaliana. Brassicaceae plants have three orthologous copies of AtMYB28 derived from recent genome triplication. These BrMYB28 genes have a high level of sequence homology, with 81–87 % similarities in the coding DNA sequence compared to Arabidopsis. Overexpression of three paralogous BrMYB28 genes in transgenic Chinese cabbage increased the total GSL content in all Tb>1b> generation plants and in two inbred lines of homozygous Tb>2b> plants. The highest total GSL contents were detected in homozygous Tb>2b> lines overexpressing BrMYB28.1, which showed an approximate fivefold increase compared to that of nontransgenic plants. The homozygous Tb>2b> lines with overexpressed BrMYB28.1 also showed an increased content of aliphatic, indolic, and aromatic GSLs compared to that of nontransgenic plants. Furthermore, all of the three BrMYB28 genes were identified as negative regulators of BrAOP2 and positive regulators of BrGSL-OH in the homozygous Tb>2b> lines. These data indicate the regulatory mechanism of GSL biosynthesis in B. rapa is unlike that in A. thaliana. Our results will provide useful information for elucidating the regulatory mechanism of GSL biosynthesis in polyploid plants.