Diversity and Antioxidant Activity of Culturable Endophytic Fungi from Alpine Plants of Rhodiola crenulata, R. angusta, and R. sachalinensis

Abstract

Rhodiola spp. are rare and endangered alpine plants widely used as medicines and food additives by many civilizations since ancient times. Their main effective ingredients (such as salidroside and p-tyrosol) are praised to exhibit pharmacologic effects on high-altitude sickness and possess anti-aging and other adaptogenic capacities based on their antioxidant properties. In this study, 347 endophytic fungi were isolated from R. crenulata, R. angusta, and R. sachalinensis, and the molecular diversity and antioxidant activities of these fungi were investigated for the first time. These fungi were categorized into 180 morphotypes based on cultural characteristics, and their rRNA gene ITS sequences were analyzed by BLAST search in the GenBank database. Except for 12 unidentified fungi (6.67%), all others were affiliated to at least 57 genera in 20 orders of four phyla, namely, Ascomycota (88.89%), Basidiomycota (2.78%), Zygomycota (1.11%), and Glomeromycota (0.56%), which exhibited high abundance and diversity. Antioxidant assay showed that the DPPH radical-scavenging rates of 114 isolates (63.33%) were >50%, and those of five isolates (Rct45, Rct63, Rct64, Rac76, and Rsc57) were >90%. The EC50 values of five antioxidant assays suggested significant potential of these fungi on scavenging DPPH•, O2−•, and OH• radicals, as well as scavenging nitrite and chelating Fe2+, which showed preference and selection between endophytic fungi and their hosts. Further research also provided the first evidence that Rac12 could produce salidrosides and p-tyrosol. Results suggested that versatile endophytic fungi associated with Rhodiola known as antioxidants could be exploited as potential sources of novel antioxidant products.

Fungal endophytes promote the accumulation of Amaryllidaceae alkaloids in Lycoris radiata

“…Among these fungal strains, members in the genera Fusarium, Gibberella, Phyllosticta, Colletotrichum, Aspergillus, Penicillium, Phoma, Glomerella and Diaporthe are widely distributed in nature and have a high spore production (Mishra et al, 2012), which give them more chances to colonize a wide range of plants (Schulz and Boyle, 2005;Aly et al, 2011;Zheng et al, 2016). Moreover, species in Galactomyces (Clay et al, 2016), Cylindrocarpon (Wearn et al, 2012), Stagonosporopsis (Cui et al, 2015) and Sarocladium (Potshangbam et al, 2017) have been observed as fungal endophytes in specific plants. In particular, Penicillium sp.…”

Endophytic Fungi as Novel Resources of natural Therapeutics

“…Antioxidant was screened [ 188 ] with the 2,2'-azinodi(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) decolorization assay and 2,2'-diphenyl-1-picrylhydrazyl (DPPH) found this EF have potential novel source of natural antioxidants. Antioxidant was screened for EF in medicinal plants Rhodiola crenulata, R. angusta, and R. sachalinensis [ 189 ]. DPPH, FRAP, and Iron chelating activity are conducted using endophytes Asperigillus niger , Penicillium sp.…”

Endophytic fungi residing in medicinal plants have the ability to produce the same or similar pharmacologically active secondary metabolites as their hosts

“…Screening of 347 endophytic fungal strains isolated from rhizomes of R. crenulata, R. angusta and R. sachalinensis revealed that four endophytic fungi were capable of producing salidrosides and p-tyrosol (Cui et al, 2015). One of these endophytic fungi identifi ed as Phialocephala fortinii was able to stably produce large amounts of salidrosides and p-tyrosol, 2.3 and 2 mg/ml of culture medium, respectively (Cui et al, 2016).…”