Identification of key gene networks controlling polysaccharide accumulation in different tissues of Polygonatum cyrtonema Hua by integrating metabolic phenotypes and gene expression profiles

Abstract

Plant polysaccharides, a type of important bioactive compound, are involved in multiple plant defense mechanisms, and in particular polysaccharide-alleviated abiotic stress has been well studied. Polygonatum cyrtonema Hua (P. cyrtonema Hua) is a medicinal and edible perennial plant that is used in traditional Chinese medicine and is rich in polysaccharides. Previous studies suggested that sucrose might act as a precursor for polysaccharide biosynthesis. However, the role of sucrose metabolism and transport in mediating polysaccharide biosynthesis remains largely unknown in P. cyrtonema Hua. In this study, we investigated the contents of polysaccharides, sucrose, glucose, and fructose in the rhizome, stem, leaf, and flower tissues of P. cyrtonema Hua, and systemically identified the genes associated with the sucrose metabolism and transport and polysaccharide biosynthesis pathways. Our results showed that polysaccharides were mainly accumulated in rhizomes, leaves, and flowers. Besides, there was a positive correlation between sucrose and polysaccharide content, and a negative correlation between glucose and polysaccharide content in rhizome, stem, leaf, and flower tissues. Then, the transcriptomic analyses of different tissues were performed, and differentially expressed genes related to sucrose metabolism and transport, polysaccharide biosynthesis, and transcription factors were identified. The analyses of the gene expression patterns provided novel regulatory networks for the molecular basis of high accumulation of polysaccharides, especially in the rhizome tissue. Furthermore, our findings explored that polysaccharide accumulation was highly correlated with the expression levels of SUS, INV, SWEET, and PLST, which are mediated by bHLH, bZIP, ERF, ARF, C2H2, and other genes in different tissues of P. cyrtonema Hua. Herein, this study contributes to a comprehensive understanding of the transcriptional regulation of polysaccharide accumulation and provides information regarding valuable genes involved in the tolerance to abiotic stresses in P. cyrtonema Hua.

CO2‐NBs‐ assisted enzymatic hydrolysis as a new green approach for extraction of phenolic compounds from rhizomes of Polygonatum cyrtonema Hua

“…The Polygonati rhizome , also referred as (Huangjing), not only does it features prominently in the Chinese as a herb, but also widely distribution in the whole world (Chen et al ., 2022). Traditionally, the Polygonatum rhizome has been used as a medicinal resource traditionally, setting it apart from the other parts of the plant of medicine, unlike the rest of the plant (Qi et al ., 2022).…”

“…Besides, how to improve the bioavailability and biological activity of the plant nutrients contained in this valuable herbal resource in it is also a problem that researchers continue to explore at both home and abroad. Currently, the study of bioactive components within P. cyrtonema Hua mainly concentrated on the polysaccharides, with a specific focus on their potential antitumor activity and underlying mechanisms of biological activity action (Huang et al ., 2020; Chen et al ., 2022). However, another substance, such as phenolic, has been concluded in the scope of active ingredients.…”

Research overview on the genetic mechanism underlying the biosynthesis of polysaccharide in tuber plants

“…In contrast, INV plays a role in breaking down sucrose into fructose and glucose in plants. It is involved in cell osmotic regulation and the accumulation of sugar in storage organs, providing substrates for the subsequent synthesis of polysaccharides ( Chen et al, 2022 ). HXK facilitates glucose phosphorylation in plant cells, while fructose undergoes phosphorylation by fructose kinase prior to metabolism.…”

The Functional Components of By-Product Resources from the Aerial Parts of Polygonatum cyrtonema Hua

“…Numerous studies have been conducted to demonstrate that carbohydrates were the primary components of Polygonatum's aerial parts. Several studies compared the carbohydrate composition of the stems, leaves, and flowers, and it was found that the flowers had the highest polysaccharide content, and the stems had the highest content of fructose and glucose [7]. In addition, the seeds contained a large amount of starch, with a content proportion of about 60.9-65.2% of the total; moreover, the soluble sugar content in the seeds of PC was as high as 28.4% [8].…”