Codonopsis lanceolata and Nelumbo nucifera Gaertn. root extracts for functional food: metabolic profiling by MS, FTIR and fluorescence and evaluation of cytotoxicity and anti-obesity properties on 3T3-L1 cell line

Codonopsis pilosula seedling drought- responsive key genes and pathways revealed by comparative transcriptome

Background

Codonopsis pilosula (Campanulaceae) is a traditional herbal plant that is widely used in China, and the drought stress during the seedling stage directly affects the quality, ultimately impacting its yield. However, the molecular mechanisms underlying the drought resistance of C. pilosula seedlings remain unclear.

Method

Herein, we conducted extensive comparative transcriptome and physiological studies on two distinct C. pilosula cultivar (G1 and W1) seedlings subjected to a 4-day drought treatment.

Results

Our findings revealed that cultivar G1 exhibited enhanced retention of proline and chlorophyll, alongside a marked elevation in peroxidase activity, coupled with diminished levels of malondialdehyde and reduced leaf relative electrolyte leakage compared with cultivar W1. This suggested that cultivar G1 had relatively higher protective enzyme activity and ROS quenching capacity. We discerned a total of 21,535 expressed genes and identified 4,192 differentially expressed genes (DEGs) by RNA sequencing (RNA-seq). Our analysis revealed that 1,764 DEGs unique to G1 underwent thorough annotation and functional categorization utilizing diverse databases. Under drought conditions, the DEGs in G1 were predominantly linked to starch and sucrose metabolic pathways, plant hormone signaling, and glutathione metabolism. Notably, the drought-responsive genes in G1 were heavily implicated in hormonal modulation, such as ABA receptor3-like gene (PYL9), regulation by transcription factors (KAN4, BHLH80, ERF1B), and orchestration of drought-responsive gene expression. These results suggest that cultivar G1 possesses stronger stress tolerance and can better adapt to drought growing conditions. The congruence between qRT-PCR validation and RNA-seq data for 15 DEGs further substantiated our findings.

Conclusion

Our research provides novel insights into the physiological adaptations of C. pilosula to arid conditions and lays the groundwork for the development of new, drought-tolerant C. pilosula cultivars.

Improvement in the quality and productivity of Codonopsis pilosula seedlings by dazomet soil fumigation

Dazomet is a dry powder formulation that releases toxic gas containing methyl isothiocyanate, which controls soil-borne pests and weeds, improving crop yields when applied to moist soils. To explore the efficacy of dazomet fumigation in the cultivation of the perennial herb Codonopsis pilosula, four typical cultivars (G1, G2, W1 and TCK) in Gansu Province were selected for seedling cultivation after soil fumigation (F) by dazomet, and non-fumigated soil was used as a control (CK). The experiments took 2 years to complete. The functional diversity of the soil enzymes and microorganisms, seedling emergence and physiological characteristics, and the quality and yield of Codonopsis seedlings and Radix were assessed. The results showed that the seed emergence rate, seedling re-green rate and several antioxidant enzymatic activities improved in the treatments involving soil fumigation with dazomet, and membrane lipid peroxidation in the seedlings decreased. On average, compared with those of the respective controls, the root viability and yield of the seedlings of the tested cultivars also increased by 34.87% and 42.4%, respectively, and the incidence of root rot in the seedlings was reduced by 83.9%, compared with their respective controls. After harvest, the yield increased by 23.9%, the incidence of root rot decreased by 61.3%, increase in yield and a 61.3% reduction in incidence, and the medicinal materials were determined to be safe and residue-free. The effects of fumigation were cultivar-specific and were especially prominent in G2. Therefore, soil fumigation with dazomet could improve the quality and productivity of Codonopsis pilosula seedlings. Taken together, these findings suggest that when herbs are bred by seedling transplantation, especially cultivars of good quality but poor resistance or species with rare germplasm resources, soil fumigation provides a way to improve cultivation effectiveness and, more importantly, ensures the probability of successfully breeding the species.

Night Temperature Affects the Growth, Metabolism, and Photosynthetic Gene Expression in Astragalus membranaceus and Codonopsis lanceolata Plug Seedlings

Astragalus membranaceus and Codonopsis lanceolata are two important medical herbs used in traditional Oriental medicine for preventing cancer, obesity, and inflammation. Night temperature is an important factor that influences the plug seedling quality. However, little research has focused on how the night temperature affects the growth and development of plug seedlings of these two medicinal species. In this study, uniform plug seedlings were cultivated in three environmentally controlled chambers for four weeks under three sets of day/night temperatures (25/10 °C, 25/15 °C, or 25/20 °C), the same relative humidity (75%), photoperiod (12 h), and light intensity (150 μmol·m-2·s-1 PPFD) provided by white LEDs. The results showed that night temperature had a marked influence on the growth and development of both species. The night temperature of 15 °C notably enhanced the quality of plug seedlings evidenced by the increased shoot, root, and leaf dry weights, stem diameter, and Dickson's quality index. Moreover, a night temperature of 15 °C also stimulated and increased contents of primary and secondary metabolites, including soluble sugar, starch, total phenols and flavonoids. Furthermore, the 15 °C night temperature increased the chlorophyll content and stomatal conductance and decreased the hydrogen peroxide content. Analysis of the gene expression showed that granule-bound starch synthase (GBSS), ribulose bisphosphate carboxylase large chain (RBCL), and ferredoxin (FDX) were up-regulated when the night temperature was 15 °C. Taken together, the results suggested that 15 °C is the optimal night temperature for the growth and development of plug seedlings of A. membranaceus and C. lanceolata.