Physcion

Polygonum cuspidatum, a key source of resveratrol and polydatin, faces cultivation challenges due to drought, which impairs plant growth and bioactive compound synthesis. This study investigated the effects of inoculating P. cuspidatum with arbuscular mycorrhizal fungus Funneliformis mosseae on its drought resilience and bioactive compound accumulation under drought stress. Although drought significantly reduced mycorrhizal colonization rates, inoculation with F. mosseae under drought still significantly enhanced aerial growth (plant height, stem diameter, leaf number, and aboveground biomass), phosphorus (P) levels, nitrogen balance index, and root development (total length, projected area, surface area, and volume). Drought stress profoundly elevated leaf superoxide dismutase, peroxidase (POD), and catalase (CAT) activities and proline levels, while F. mosseae further amplified these enzyme activities, particularly boosting POD and CAT under well-watered conditions and all three antioxidant enzymes under drought conditions, followed by a substantial decrease in proline levels. Drought diminished the levels of four active components (polydatin, resveratrol, aloe-emodin, and physcion), while F. mosseae differentially enhanced the levels of specific medicinal components, as evidenced by an increase in polydatin, resveratrol, aloe-emodin, and physcion under well-watered and an elevation in polydatin, resveratrol, aloe-emodin, and chrysophanol under drought. Gene expression analysis revealed that drought triggerred the down-regulated expression of resveratrol biosynthesis genes, while F. mosseae upregulated all six tested genes under well-watered conditions and selectively enhanced PcCHS1, PcCHS12, PcRS11, and PcCRS1 under drought conditions. This emphasizes that arbuscular mycorrhizal fungal inoculation is a promising strategy to enhance plant establishment and bioactive compound accumulation of P. cuspidatum in drought-prone environments.

Emblica blue mold, a fungal disease caused by Penicillium choerospondiatis, poses a major threat to the industry of Phyllanthus emblica. Currently, resistance to chemical fungicides has been a challenge to its effectiveness on this disease. To explore an effective botanical fungicide as alternatives for chemical fungicides to inhibit P. choerospondiatis, 10 botanical fungicides were selected for antifungal activity test against P. choerospondiatis mycelial growth. Results showed that physcion was the most effective one with a 50 % effective concentration (EC₅₀) of 3.30 mg/L. Furthermore, physcion had a strong inhibition activity to spore germination and pathogenicity of P. choerospondiatis, both in vitro and in vivo. Its antifungal mechanisms investigations indicated that physcion could alter the mycelium morphology, disrupt cell membrane integrity, increase cell membrane permeability, reduce ergosterol content, and induce excessive reactive oxygen species (ROS). Moreover, transcriptome analysis revealed that physcion might interfere with ergosterol biosynthesis and oxidoreductase activity, leading to significant cell membrane dysfunction and oxidative stress in P. choerospondiatis. This study lays the groundwork for elucidating how physcion harms the pathogen and provides promising insights into eco-friendly alternatives for controlling this postharvest disease in P. choerospondiatis.