Bioactivity and genetic diversity of endophytic fungi in Rhododendron tomentosum Harmaja

Abstract

Eighty-seven endophytic fungi were isolated from asymptomatic leaf tissues of Rhododendron tomentosum. Most of the isolates were non-sporulating and therefore difficult to identify exclusively based on morphological characters. Eighteen isolates that were morphologically distinct were selected for identification by sequencing the ITS region. For culture-independent analysis, the DNA was isolated from the surface-sterilized leaves of R. tomentosum and the ITS region was amplified using fungal specific primers ITS1F and ITS4, cloned, and 11 clones were randomly selected and sequenced. The phylogenetic analysis was performed with MEGA4 on a total of 49 sequences, including 18 endophytic isolates and 11 unculturables obtained in this study, and 20 sequences from Genbank, which were distributed in four clusters. The culturable and unculturable endophytes formed separate clades and were clearly distinguishable with no overlap within the groups. Endophytic fungi are a well-recognized source of bioactive compounds and therefore antibacterial and antioxidant activities of the isolates of R. tomentosum were studied. All isolates were grown in two different media, enriched (MEB) and depleted (DM), and screened for antibacterial and antioxidant activities. As a result, 10% produced antibacterials and 14% antioxidants, in total 24% of the isolates had biological activity. Antioxidant broth of TRT59 was partially purified using HPLC. The majority of antibacterial compounds were produced in DM media and antioxidants in MEB media. Therefore, it is advisable to test various media for production of antibacterials and antioxidants.

Endophytic fungi harbored in Panax notoginseng : diversity and potential as biological control agents against host plant pathogens of root-rot disease

“…Even so, endophytic fungi are still a poorly investigated group of microorganisms [38], and their complex ecological functions remain to be extensively exploited. P. notoginseng , Panax ginseng , and Panax quinquefolius , have been widely used for medicinal plants all over the world.…”

Diversity, distribution and biotechnological potential of endophytic fungi

“…For endophytic fungi, some classical media are available, such as potato dextrose agar (PDA) (Rivera-Orduña et al 2011;Li et al 2012b), corn meal malt agar (CMMA) (Kleczewski et al 2012), malt extract agar (MEA) (Sun et al 2011;Tejesvi et al 2011), water agar (WA) (Tejesvi et al 2011;Qi et al 2012), Sabouraud maltose agar (SMA) (Qi et al 2012), Sabouraud dextrose agar (SAB) (de Siqueira et al 2011), Czapek agar (CZA) (Qi et al 2012), corn meal agar+2 % dextrose (CMD) (Gazis and Chaverri 2010), KenknightMunaier′s medium (Qadri et al 2014), nutrient broth (Pancher et al 2012), and so on. Some low nutrient media, such as synthetic low nutrient agar (SNA) and carnation leaf agar (CLA) have proved effective for isolation of specific endophytic fungi (Arnold and Herre 2003).…”

Untitled

“…and Arthrinium sp. from Rhododendron tomentosum Harmaja were found to produce more antioxidant compounds in enriched media 96 . (Figure 2) produced by an endophytic strain Rahnella aquatilis from Taiwanese herbal plant Emilia sonchifolia were shown to have notable inhibitory effects on platelet aggregation 79 .…”