Journal Article

Tissue-specific transcriptome analyses reveal candidate genes for stilbene, flavonoid and anthraquinone biosynthesis in the medicinal plant Polygonum cuspidatum

Hu, Hongyan, Fan, Haili, Wang, Hong, Wang, Guowei, Wang, Xiaowei, Chai, Tuanyao, Wu, Zhijun

2021

Overview

Background Polygonum cuspidatum Sieb. et Zucc. is a well-known medicinal plant whose pharmacological effects derive mainly from its stilbenes, anthraquinones, and flavonoids. These compounds accumulate differentially in the root, stem, and leaf; however, the molecular basis of such tissue-specific accumulation remains poorly understood. Because tissue-specific accumulation of compounds is usually associated with tissue-specific expression of the related biosynthetic enzyme genes and regulators, we aimed to clarify and compare the transcripts expressed in different tissues of P. cuspidatum in this study. Results High-throughput RNA sequencing was performed using three different tissues (the leaf, stem, and root) of P. cuspidatum . In total, 80,981 unigenes were obtained, of which 40,729 were annotated, and 21,235 differentially expressed genes were identified. Fifty-four candidate synthetase genes and 12 transcription factors associated with stilbene, flavonoid, and anthraquinone biosynthetic pathways were identified, and their expression levels in the three different tissues were analyzed. Phylogenetic analysis of polyketide synthase gene families revealed two novel CHS genes in P. cuspidatum . Most phenylpropanoid pathway genes were predominantly expressed in the root and stem, while methylerythritol 4-phosphate and isochorismate pathways for anthraquinone biosynthesis were dominant in the leaf. The expression patterns of synthase genes were almost in accordance with metabolite profiling in different tissues of P. cuspidatum as measured by high-performance liquid chromatography or ultraviolet spectrophotometry. All predicted transcription factors associated with regulation of the phenylpropanoid pathway were expressed at lower levels in the stem than in the leaf and root, but no consistent trend in their expression was observed between the leaf and the root. Conclusions The molecular knowledge of key genes involved in the biosynthesis of P. cuspidatum stilbenes, flavonoids, and anthraquinones is poor. This study offers some novel insights into the biosynthetic regulation of bioactive compounds in different P. cuspidatum tissues and provides valuable resources for the potential metabolic engineering of this important medicinal plant.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Animal Genetics and Genomics / Annotations / Anthraquinone / Anthraquinones / Aquatic plants / Bioaccumulation / Bioactive compounds / Bioflavonoids / Biomedical and Life Sciences / Biosynthesis / Carotenoids / Cell division / Fallopia japonica - genetics / Flavones / Flavonoids / Gene expression / Gene Expression Profiling / Gene Expression Regulation, Plant / Gene families / Gene regulation / Gene sequencing / Genes / Genetic aspects / Genetic transcription / Genomes / Genomics / Herbal medicine / High-performance liquid chromatography / Humans / Leaves / Life Sciences / Liquid chromatography / Medicinal plants / Metabolic engineering / Metabolism / Metabolites / Microarrays / Microbial Genetics and Genomics / Pediomelum cuspidatum / Phylogeny / Physiological aspects / Phytochemicals / Plant Genetics and Genomics / Plant genomics / Plants, Medicinal / Polygonum / Polygonum cuspidatum / Polyketide synthase / Principal components analysis / Proteomics / Research Article / RNA sequencing / Spectrophotometry / Stems / Stilbene / Stilbenes / Tissues / Transcription factors / Transcriptome / Transcriptomes