Strepimidazoles A–G from the Plant Endophytic Streptomyces sp. PKU-EA00015 with Inhibitory Activities against a Plant Pathogenic Fungus

Abstract

Seven new 4-acyl-2-aminoimidazoles, designated strepimidazoles A–G (1–7), were discovered from the endophytic Streptomyces sp. PKU-EA00015 isolated from Salvia miltiorrhiza Bunge, whose dry root “Danshen” is one of the most widely used traditional Chinese medicines. The resonance signals of the 2-aminoimidazole moiety in 1–7 were absent in the NMR spectra due to tautomerization, and the structures of 1–7 were identified after preparation of their acetylation products 1a–7a, respectively. Compounds 1–7 represent a new family of 2-aminoimidazole-containing natural products, enriching the structural diversity of natural products from endophytic origin. Compounds 1–7 showed different degrees of inhibitory activities against the plant pathogenic fungus Verticillium dahliae V991, revealing structure–activity relationships on the acyl moieties. The plant pathogenic fungus V. dahliae has been confirmed to cause serious chlorosis of cultivated S. miltiorrhiza Bunge in China. This study opens the door for further investigation of mutualistic relationships between S. miltiorrhiza Bunge and their endophytic actinomycetes and for possible antifungal agent development for biological control of V. dahliae in the future.

Biotransformation ability of endophytic fungi: from species evolution to industrial applications

“…SC-J0138 Diaporthichalasin D Cytotoxic activity Yang et al ( 2020a ) 44 Diaporthichalasin H 45 Nicotiana tabacum Rhizopycnis vagum KM095527 Rhizoperemophilane J Wang et al ( 2020 ) 46 Rhizoperemophilane N 47 Salvia miltiorrhiza Streptomyces sp. PKU-EA00015 Strepimidazoles A Antifungal activity Sun et al ( 2020 ) 48 Strepimidazoles B 49 Strepimidazoles C 50 Strepimidazoles D 51 Strepimidazoles E 52 Strepimidazoles F 53 Strepimidazoles G 54 Elaeis guineensis Jacq Streptomyces palmae CMU-AB204 ( Z )-5-(o-tolyl)pent-4-enoic acid Antifungal activity Sujarit et al ( 2020 ) 55 ( Z )-7-(o-tolyl)hept-6-enoic acid 56 ( Z )-11-(o-tolyl)undec-10-enoic acid Antibacterial activity 57 ( Z )-12-(o-tolyl)dodec-11-enoic acid 58 Aconitum vilmorinianum Penicillium variabile HM469398 Maz...…”

Endophytic Fungi: Biological Control and Induced Resistance to Phytopathogens and Abiotic Stresses

“…Finally, perspectives are presented to better understand how the endophytic fungi area should evolve in the coming years. Although endophytic bacteria can also act to protect plants against biotic [ 25 , 26 , 27 ] and abiotic stresses, this is not the focus of this review.…”

Discovery and Biosynthetic Studies of a Highly Reduced Cinnamoyl Lipid, Tripmycin A, from an Endophytic Streptomyces sp.

“…2,3 It has been suggested that some metabolites initially described from plants are either microbial products or mutual products of plants and endophytes. 4,5 This unique ecological origin makes endophytes a potential source for the discovery of novel products, such as polyketides, 6 macrolides, 7 alkaloids, 8,9 and terpenes, 10 for future drug development. 11,12 Cinnamoyl-containing natural products (CCNPs) featuring an ortho-substituted cinnamoyl group exhibit various bioactivities including antibacterial, antifungal, antitumor, and antiangiogenic.…”

“…Endophytes have evolved many special enzymatic systems to adapt their symbioses with plants . The mutualism between endophytes and plants not only enables endophytes to utilize various nutrients or substances from plants but also stimulates endophytes to produce biologically active compounds. , It has been suggested that some metabolites initially described from plants are either microbial products or mutual products of plants and endophytes. , This unique ecological origin makes endophytes a potential source for the discovery of novel products, such as polyketides, macrolides, alkaloids, , and terpenes, for future drug development. , …”