Pecan agroforestry systems improve soil quality by stimulating enzyme activity

Background Forest and plantation intercropping are efficient agroforestry systems that optimize land use and promote agroforestry around the world. However, diverse agroforestry systems on the same upper-plantation differently affect the physical and chemical properties of the soil. Methods The treatments for this study included a single cultivation (CK) pecan control and three agroforestry systems (pecan + Paeonia suffruticosa + Hemerocallis citrina, pecan + Paeonia suffruticosa, and pecan + Paeonia lactiflora). Soil samples were categorized according to the sampling depth (0–20 cm, 20–40 cm, 40–60 cm). Results The results demonstrated that the bulk density (BD) of soil under the pecan agroforestry system (PPH and PPL) was reduced by 16.13% and 7.10%, respectively, and the soil moisture content (MC) and total soil porosity (TPO) increased. Improvements in the physical properties of the soil under the PPS agroforestry system were not obvious when compared with the pecan monoculture. The soil total phosphorus (TP), total nitrogen (TN), available potassium (AK), and total carbon (TC) increased significantly, while the soil urease (S-UE), alkaline phosphatase (S-AKP), and 1,4-β-N-acetylglucosamines (S-NAG) enzyme activity also increased significantly, following agroforestry. Overall, the pecan agroforestry system significantly improved the physical properties of the pecan plantation soil, enriched the soil nutrients, and increased the activity of soil enzymes related to TC, TN, and TP cycles.

Evaluations and Mechanistic Interrogation of Natural Products Isolated From Paeonia suffruticosa for the Treatment of Inflammatory Bowel Disease

Mu Dan Pi (MDP), a traditional Chinese medicine derived from the root bark of Paeonia suffruticosa Andrews, is used to treat autoimmune diseases due to its anti-inflammatory properties. However, the impact of MDP on inflammatory bowel disease (IBD) and its principal active compounds that contribute to the anti-inflammatory properties are uncertain. Thus, this study systemically evaluated the anti-inflammatory effects of fractionated MDP, which has therapeutic potential for IBD. MDP fractions were prepared by multistep fractionation, among which the ethyl acetate-fraction MDP5 exhibited the highest potency, with anti-inflammatory activity screened by the Toll-like receptor (TLR)-2 agonist, Pam3CSK4, in a cell-based model. MDP5 (at 50 μg/ml, p < 0.001) significantly inhibited nuclear factor kappa-B (NF-κB) reporters triggered by Pam3CSK4, without significant cell toxicity. Moreover, MDP5 (at 10 μg/ml) alleviated proinflammatory signaling triggered by Pam3CSK4 in a dose-dependent manner and reduced downstream IL-6 and TNF-α production (p < 0.001) in primary macrophages. MDP5 also mitigated weight loss, clinical inflammation, colonic infiltration of immune cells and cytokine production in a murine colitis model. Index compounds including paeoniflorin derivatives (ranging from 0.1 to 3.4%), gallic acid (1.8%), and 1,2,3,4,6-penta-O-galloyl-β-D-glucose (1.1%) in MDP5 fractions were identified by LC-MS/MS and could be used as anti-inflammatory markers for MDP preparation. Collectively, these data suggest that MDP5 is a promising treatment for IBD patients.

Integrating full-length transcriptomics and metabolomics reveals the regulatory mechanisms underlying yellow pigmentation in tree peony (Paeonia suffruticosa Andr.) flowers

Tree peony (Paeonia suffruticosa Andr.) is a popular ornamental plant in China due to its showy and colorful flowers. However, yellow-colored flowers are rare in both wild species and domesticated cultivars. The molecular mechanisms underlying yellow pigmentation remain poorly understood. Here, petal tissues of two tree peony cultivars, “High Noon” (yellow flowers) and “Roufurong” (purple–red flowers), were sampled at five developmental stages (S1–S5) from early flower buds to full blooms. Five petal color indices (brightness, redness, yellowness, chroma, and hue angle) and the contents of ten different flavonoids were determined. Compared to “Roufurong,” which accumulated abundant anthocyanins at S3–S5, the yellow-colored “High Noon” displayed relatively higher contents of tetrahydroxychalcone (THC), flavones, and flavonols but no anthocyanin production. The contents of THC, flavones, and flavonols in “High Noon” peaked at S3 and dropped gradually as the flower bloomed, consistent with the color index patterns. Furthermore, RNA-seq analyses at S3 showed that structural genes such as PsC4Hs, PsDFRs, and PsUFGTs in the flavonoid biosynthesis pathway were downregulated in “High Noon,” whereas most PsFLSs, PsF3Hs, and PsF3’Hs were upregulated. Five transcription factor (TF) genes related to flavonoid biosynthesis were also upregulated in “High Noon.” One of these TFs, PsMYB111, was overexpressed in tobacco, which led to increased flavonols but decreased anthocyanins. Dual-luciferase assays further confirmed that PsMYB111 upregulated PsFLS. These results improve our understanding of yellow pigmentation in tree peony and provide a guide for future molecular-assisted breeding experiments in tree peony with novel flower colors.

The PsMYB12L/PsDFR Module is Involved in Double-Color Formation in Paeonia Suffruticosa ‘Shima Nishiki’

Background: Paeonia suffruticosa ‘Shima Nishiki’ is a extremely precious double-color cultivar in the world because of its unique and attractive flower color. However, the underlying molecular mechanisms of its double-color formation have not been completely unravelled until now. In the present study, firstly, the full-length cDNA sequence, genomic DNA sequence, promoter region sequence of the PsDFR gene in the red and pink petals of the ‘Shima Nishiki’ cultivar were cloned and analyzed, respectively. Meanwhile, the methylation level of CpG island and promoter region of this gene in the red and pink petals was also measured. Moreover, the identification of regulatory effect of PsMYB114L/PsMYB12L and PsDFR was performed. Results: Here, we found that the full-length cDNA sequence, genomic DNA sequence, promoter region sequence of PsDFR were identical in the red and pink petals, respectively. There were some differences for the methylation level of this gene in the red and pink petals, but these differences were little and didn’t show obvious regularity. In addition, the regulatory effect of PsMYB12L and PsDFR was successfully identified. Conclusions: Based on these above results, we concluded that PsMYB12L regulating the differential expression of PsDFR may be a key reason for the double-color formation. These results will advance our understanding of the molecular regulatory mechanisms of double-color formation in P. suffruticosa ‘Shima Nishiki’.

Structure Related α-Glucosidase Inhibitory Activity and Molecular Docking Analyses of Phenolic Compounds From Paeonia Suffruticosa

In the continuous search for α-glucosidase inhibitors, eleven phenolic compounds (1-11) were isolated from the root bark of Paeonia suffruticosa. Their α-glucosidase inhibitory activity and inhibition mechanism were investigated using an in vitro inhibition assay and molecular docking studies. Compounds 2, 5, 6, and 8-11 (IC50 between 290 and 431 µM) inhibited α-glucosidase more effectively than the reference compound acarbose (IC50=1463 ± 29.5 µM). Among them, compound 10 exhibited the highest α-glucosidase inhibitory effect with an IC50 value of 290.4 ± 9.6 µM. Compounds 2, 5, 9 10 and 11 were found to be competitive inhibitors, while compounds 6 and 8 were noncompetitive inhibitors of α-glucosidase. Computational analyses showed that the main binding forces between the compounds and the main residues were hydrogen bonds. The results indicated that these compounds had considerable α-glucosidase inhibitory activity.