Latent Pathogenic Fungi in the Medicinal Plant Houttuynia cordata Thunb. Are Modulated by Secondary Metabolites and Colonizing Microbiota Originating from Soil

Abstract

Latent pathogenic fungi (LPFs) affect plant growth, but some of them may stably colonize plants. LPFs were isolated from healthy Houttuynia cordata rhizomes to reveal this mechanism and identified as Ilyonectria liriodendri, an unidentified fungal sp., and Penicillium citrinum. Sterile H. cordata seedlings were cultivated in sterile or non-sterile soils and inoculated with the LPFs, followed by the plants’ analysis. The in vitro antifungal activity of H. cordata rhizome crude extracts on LPF were determined. The effect of inoculation of sterile seedlings by LPFs on the concentrations of rhizome phenolics was evaluated. The rates of in vitro growth inhibition amongst LPFs were determined. The LPFs had a strong negative effect on H. cordata in sterile soil; microbiota in non-sterile soil eliminated such influence. There was an interactive inhibition among LPFs; the secondary metabolites also regulated their colonization in H. cordata rhizomes. LPFs changed the accumulation of phenolics in H. cordata. The results provide that colonization of LPFs in rhizomes was regulated by the colonizing microbiota of H. cordata, the secondary metabolites in the H. cordata rhizomes, and the mutual inhibition and competition between the different latent pathogens.

A Single Latent Plant Growth-Promoting Endophyte BH46 Enhances Houttuynia cordata Thunb. Yield and Quality

“…It is only reported that pathogenic fungi influence H. cordata growth and its metabolite accumulation. 10 However, no study has investigated the link between promoting H. cordata growth and PGPE, in addition to the regulatory mechanisms associated with the metabolic signals. Biotic and abiotic stresses interfere with metabolic signals of plants (e.g., cytokinin, abscisic acid, and jasmonic acid signaling), which modulate plant growth and development.…”

“…19 Colonizing microbial communities in soils with H. cordata can inhibit pathogenic fungi and promote accumulation of secondary metabolites. 10 However, whether PGPE promotes the accumulation of secondary metabolites in H. cordata and the regulatory mechanisms of the metabolic signals remain unclear.…”

“…It is only reported that pathogenic fungi influence H. cordata growth and its metabolite accumulation . However, no study has investigated the link between promoting H.…”