Arbuscular mycorrhizal fungi and phosphorus supply accelerate main medicinal component production of Polygonum cuspidatum

Abstract

The medicinal plant <i>Polygonum cuspidatum</i> Sieb. Et Zucc is rich in stilbenes (e.g., polygonin and resveratrol) and anthraquinones (e.g., emodin) for the therapy of human diseases, while how to increase the growth and medicinal composition concentrations of <i>P</i>. <i>cuspidatum</i> has become an urgent issue. The aim of the present study was to evaluate the effects of inoculation with an arbuscular mycorrhizal (AM) fungus, <i>Funneliformis mosseae</i>, on plant growth, phosphorus (P) acquisition, medicinal component concentrations, and expressions of resveratrol synthesis-associated enzyme genes of <i>P</i>. <i>cuspidatum</i> at two P levels (0 M and 0.2 M). P supply (0.2 M) stimulated root AM fungal colonization rate. <i>F</i>. <i>mosseae</i> inoculation significantly improved growth performance (height, diameter, and biomass) and root morphology (diameter, length, and projected area), irrespectively of substrate P levels. P supply and <i>F</i>. <i>mosseae</i> distinctly increased soil acid and neutral phosphatase activities, as well as root P concentrations. P supply increased root physcion and resveratrol concentrations in inoculated and uninoculated plants, along with up-regulated expressions of <i>PcCHS1</i>, <i>PcCRS1</i>, <i>PcRS11</i>, and <i>PcSTS</i>. AM plants represented significantly higher root aloe-emodin, chrysophanol, emodin, physcion, polydatin, and resveratrol concentrations than non-AM plants irrespective of P levels, coupled with up-regulated expressions of <i>PcCHS1</i>, <i>PcCHS2</i>, <i>PcRS11</i>, <i>PcRS</i>, and <i>PcSTS</i>. It is concluded that 0.2 M P supply and <i>F</i>. <i>mosseae</i> inoculation promoted chrysophanol, physcion, polydatin, and resveratrol concentrations of <i>P</i>. <i>cuspidatum</i>, with the increase in resveratrol associated with up-regulated expressions of related genes.