Improvement of Panax notoginseng saponin accumulation triggered by methyl jasmonate under arbuscular mycorrhizal fungi.

Panax notoginseng is a highly valued perennial medicinal herb plant in Yunnan Province, China, and the taproots are the main medicinal parts that are rich in active substances of P. notoginseng saponins. The main purpose of this study is to uncover the physiological and molecular mechanism of Panax notoginseng saponin accumulation triggered by methyl jasmonate (MeJA) under arbuscular mycorrhizal fungi (AMF) by determining physiological indices, high-throughput sequencing and correlation analysis. Physiological results showed that the biomass and saponin contents of P. notoginseng, the concentrations of jasmonic acids (JAs) and the key enzyme activities involved in notoginsenoside biosynthesis significantly increased under AMF or MeJA, but the interactive treatment of AMF and MeJA weakened the effect of AMF, suggesting that a high concentration of endogenous JA have inhibitory effect. Transcriptome sequencing results indicated that differential expressed genes (DEGs) involved in notoginsenoside and JA biosynthesis were significantly enriched in response to AMF induction, e.g., upregulated genes of diphosphocytidyl-2-C-methyl-d-erythritol kinases (ISPEs), cytochrome P450 monooxygenases (CYP450s)_and glycosyltransferases (GTs), while treatments AMF-MeJA and salicylhydroxamic acid (SHAM) decreased the abundance of these DEGs. Interestingly, a high correlation presented between any two of saponin contents, key enzyme activities and expression levels of DEGs. Taken together, the inoculation of AMF can improve the growth and saponin accumulation of P. notoginseng by strengthening the activities of key enzymes and the expression levels of encoding genes, in which the JA regulatory pathway is a key link. This study provides references for implementing ecological planting of P. notoginseng, improving saponin accumulation and illustrating the biosynthesis mechanism.

Comprehensive Analysis of 34 Edible Flowers by the Determination of Nutritional Composition and Antioxidant Capacity Planted in Yunnan Province China.

The main purpose of this study was to reveal the nutritional value and antioxidant activity of 34 edible flowers that grew in Yunnan Province, China, through a comprehensive assessment of their nutritional composition and antioxidant indices. The results showed that sample A3 of Asteraceae flowers had the highest total flavonoid content, with a value of 8.53%, and the maximum contents of vitamin C and reducing sugars were from Rosaceae sample R1 and Gentianaceae sample G3, with values of 143.80 mg/100 g and 7.82%, respectively. Samples R2 and R3 of Rosaceae were the top two flowers in terms of comprehensive nutritional quality. In addition, the antioxidant capacity of Rosaceae samples was evidently better than that of three others, in which Sample R1 had the maximum values in hydroxyl radical (·OH) scavenging and superoxide anion radical (·O2-) scavenging rates, and samples R2 and R3 showed a high total antioxidant capacity and 2,2-diphenyl-1-pyridylhydrazine (DPPH) scavenging rate, respectively. Taken together, there were significant differences in the nutrient contents and antioxidant properties of these 34 flowers, and the comprehensive quality of Rosaceae samples was generally better than the other three families. This study provides references for 34 edible flowers to be used as dietary supplements and important sources of natural antioxidants.

A Panax notoginseng phosphate transporter, PnPht1;3, greatly contributes to phosphate and arsenate uptake.

The crisis of arsenic (As) accumulation in rhizomes threatens the quality and safety of Panax notoginseng (Burk.) F.H. Chen, which is a well-known traditional Chinese herb with a long clinical history. The uptake of arsenate (AsV) could be suppressed by supplying phosphate (Pi), in which Pi transporters play important roles in the uptake of Pi and AsV. Herein, the P . notoginseng Pi transporter-encoding gene PnPht1;3 was identified and characterised under Pi deficiency and AsV exposure. In this study, the open reading frame (ORF) of PnPht1;3 was cloned according to RNA-seq and encoded 545 amino acids. The relative expression levels revealed that PnPht1;3 was significantly upregulated under phosphate deficiency and AsV exposure. Heterologous expression in Saccharomyces cerevisiae MB192 demonstrated that PnPht1;3 performed optimally in complementing the yeast Pi-transport defect and accumulated more As in the cells. Combined with the subcellular localisation prediction, it was concluded that PnPht1;3 encodes a functional plasma membrane-localised transporter protein that mediates putative high-affinity Pi/H+ symport activity and enhances the uptake of Pi and AsV. Therefore, a better understanding of the roles of the P . notoginseng Pi transporter could provide new insight for solving As accumulation in medicinal plants.