Co-occurrence of two ascomycete endophytes as the specialized metabolite production partners in Rheum spiciforme Royle

• Published in: Symbiosis (Philadelphia, Pa.) Vol. 90; no. 1; pp. 1 - 16
• Main Authors: Khan, Mohd Ishfaq, Bashir, Nargis, Pandith, Shahzad A., Shahzad, Anwar, Barvkar, Vitthal T., Pable, Anupama A., Shah, Manzoor A., Reshi, Zafar A.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.05.2023; Springer Nature B.V
• Subjects: Anthraquinone; Bioactive compounds; Biomedical and Life Sciences; Calmodulin; Developmental Biology; Ecology; Emodin; Endophytes; Evolutionary Biology; Flavonoids; Herbal medicine; Life Sciences; Maximum likelihood method; Medicinal plants; Microbiology; Naringenin; Nucleotide sequence; Phenotypes; Phylogeny; Physical characteristics; Piceatannol; Plant Sciences; Quercetin; Resveratrol; Ribosomal DNA; Rutin; Flavonoids; DNA barcode; Anthraquinones; LC-QTOF-MS; Endophyte; Phylogeny; Stilbenoids
• ISSN: 0334-5114; 1878-7665
• DOI: 10.1007/s13199-023-00915-x

Two filamentous endophytic ascomycete fungi with different phenotypes were isolated and characterized from the vegetative tissue of Rheum spiciforme , a threatened and endemic trans-Himalayan medicinal herb. The visible morphological characteristics and microscopic features allowed the recognition of the endophytes as Fusarium proliferatum and Aureobasidium pullulans . Molecular identification involved partial DNA sequence analyses of internal transcribed spacer (ITS), elongation factor 1α (EF-1α), and calmodulin (CAL) regions of F. proliferatum DNA, and ITS and large subunit (LSU) of the nuclear ribosomal DNA (rDNA) of A. pullulans . The respective phylogenetic analyses by the Maximum Likelihood Method based on the combined ITS-EF-1α-CAL and ITS-LSU sequences showed that the former isolate is closest to F. proliferatum and the latter to A. pullulans. Moreover, using the LC-QTOF-MS technique, selected populations of R. spiciforme (one population with endophytes and another showing no apparent colonization), as well as the isolated endophytes, were evaluated for various specialized chemical constituents belonging to anthraquinone (rhein, physcion, emodin, and aloe-emodin), stilbenoid (piceatannol and resveratrol), and flavonoid (rutin, quercetin, and naringenin) class of compounds. Except for rutin, the results demonstrated that the identified endophytes possibly play an important role in sharing the metabolite synthesis machinery of the host. The current study may contribute to a better comprehension of the host-endophyte relation and open the door to the cost-effective synthesis of highly-valuable bioactive chemicals from microbial sources.