Two Polyketides Produced by Endophytic Penicillium citrinum DBR-9 From Medicinal Plant Stephania kwangsiensis and Their Antifungal Activity Against Plant Pathogenic Fungi

Abstract

Endophytic fungi, especially those found in medicinal plants, are widely studied as producers of secondary metabolites of biotechnological interest. In this study, on the basis of an activity-directed isolation method and spectroscopic analysis, two active polyketides, citrinin (1) and emodin (2), were isolated and identified from the fermentation of the endophytic fungus Penicillium citrinum DBR-9. This fungus was isolated from the root tubers of the traditional Chinese medicinal plant Stephania kwangsiensis. In vitro antifungal assay showed that the two polyketides displayed significant inhibition on hypha growth of tested plant pathogenic fungi with IC 50 values ranging from 3.1 to 123.1 μg/mL and 3.0 to 141.0 μg/mL, respectively. In addition, the mechanism of the effects of emodin (2) on the pathogen revealed it could affect the colony morphology, destroy cell membrane integrity, and influence the protein synthesis of the tested fungal cell. This work is the first report of two polyketides-producing endophytic P. citrinum DBR-9 from the medicinal plant S. kwangsiensis. Our results present new opportunities to deeply understand the potential of these two polyketides as natural antifungal agents to control phytopathogens in agriculture.

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

“…6A-C ). The mutual restriction of hyphen growth may help maintain the balance of each LPF and may be one of the important ways by which the diversity of fungi is maintained ( Cline and Zak 2015 ; Luo et al 2019 ). The mycelial extension between IL and PC ( Fig.…”

“…The ability to produce secondary metabolites of herbal plants is a significant functional trait, which has played a crucial role in human health and disease treatment for thousands of years and has critical functions in plant physiology and ecology ( Huang et al 2019 ; Wetzel et al 2020 ). However, the accumulation of such physiologically active compounds is affected by colonizing microbes (including the fungi and bacteria) and soil, climatic, and geographic factors ( Luo et al 2019 ). Houttuynia cordata Thunb.…”

Induction of Cryptic Antifungal Pulicatin Derivatives from Pantoea Agglomerans by Microbial Co-Culture

“…On other occasions, Penicillium citrinum isolate IR-3-3 proved to possess a plant growth promoting ability, resulting in the maximum plant growth when applied to waito-c rice and Atriplex gemelinii seedling,s due to its gibberellins-producing ability [39]. The endophytic fungus Penicillium citrinum DBR-9 isolated from the root tubers of the Chinese plant Stephania kwangsiensis exhibited an in vitro antifungal effect on the hypha growth of tested plant pathogenic fungi [40]. In a study to investigate the plant growth promotion and stress mitigation effects of different Penicillium sp.…”

Exploration and Antifungal Assay of Endophytic Fungi as Biocontrol of Onion Purple Blotch Disease Caused by Alternaria porri (Ell) Cif In Vitro

“…P. citrinum produces two polyketides, emodin and citrinin. Antifungal effect of emodin causes changes in the cell membrane and structure, furthermore, this leads to morphological aberrations including swelling, distortion, increase in membrane permeability, and a decrease in the total cell protein content (Luo et al, 2019). Citrinin was reported to have broad-spectrum antifungal activity against Fusarium sp., F. nivale, and Aspergillus niveus (Hu et al, 2017).…”

“…Penctrimertone compound, bioactive citrinin dimer is an antimicrobial agent from secondary metabolites secreted by Penicillium and has been shown antimicrobial activity against several pathogenic microbes (Li et al, 2020). Based on studies of Luo et al, (2019), P. citrinum has two groups most known antifungal compound to inhibit the growth of pathogens that citrinin and emodin. Citrinin mycotoxins have been shown to inhibit the growth of pathogens from the genus Alternaria.…”