Transcriptomics Reveals Host-Dependent Differences of Polysaccharides Biosynthesis in Cynomorium songaricum

Area of Science:

• Plant biology
• Biochemistry
• Genomics

Background:

• Cynomorium songaricum, a parasitic herb, is used in traditional Chinese medicine for its bioactive compounds like polysaccharides.
• Its growth and medicinal properties are influenced by host plants, Nitraria roborowskii and Nitraria sibirica, in arid regions.
• Understanding host-parasite interactions is crucial for optimizing C. songaricum yield and quality.

Purpose of the Study:

• To investigate the physiological and transcriptomic differences of Cynomorium songaricum when hosted by Nitraria roborowskii (CR) versus Nitraria sibirica (CS).
• To identify key genes and metabolic pathways involved in growth and polysaccharide biosynthesis influenced by host variation.
• To provide a basis for enhancing the production of bioactive compounds in C. songaricum.

Main Methods:

• Comparative physiological analysis of CR and CS, measuring fresh weight, soluble sugar content, and antioxidant capacity.
• Transcriptome sequencing to identify differentially expressed genes (DEGs) between CR and CS.
• Bioinformatic analysis of DEGs, focusing on genes related to polysaccharide and starch metabolism.
• Quantitative real-time PCR (qRT-PCR) for validating gene expression levels.

Main Results:

• CR exhibited significantly higher fresh weight (3.3-fold), soluble sugar content (3.0-fold), and antioxidant capacity (2.1-fold) compared to CS.
• A total of 16,921 DEGs were identified between CR and CS, with 1725 up-regulated and 848 down-regulated.
• Fifty DEGs were associated with polysaccharide and starch metabolism and transport, suggesting host-specific regulation of these pathways.
• Gene expression validation by qRT-PCR confirmed the transcriptome sequencing results.

Conclusions:

• Nitraria roborowskii significantly promotes the growth and accumulation of bioactive compounds in Cynomorium songaricum compared to Nitraria sibirica.
• Host-driven differential gene expression, especially in carbohydrate metabolism, underlies these physiological variations.
• The findings offer valuable insights for strategies to improve the yield and quality of Cynomorium songaricum through host selection or manipulation.