https://pubs.rsc.org/en/content/articlepdf/2019/NP/C8NP00092A

Marine natural products.

Marine-derived fungi: a chemically and biologically diverse group of microorganisms

Trichoderma species are free-living fungi that are highly interactive in root, soil and foliar environments and have been used successfully in field trials to control many crop pathogens. Structural and biological studies of the metabolites isolated from Trichoderma species are reviewed. This review, encompassing all the literature in this field up to the present and in which 269 references are cited, also includes a detailed study of the biological activity of the metabolites, especially the role of these metabolites in biological control mechanisms. Some aspects of the biosynthesis of these metabolites and related compounds are likewise discussed.

Secondary metabolites from species of the biocontrol agent Trichoderma

SUMMARY A wide variety of microbial species are used in food and feed production. Some have a long history of apparent safe use, while others are less well understood and their use may represent a risk for consumers. Experience has shown that there is a need for a tool for setting priorities within the risk assessment of those microorganisms used in food/feed production referred to EFSA and consequently the subject of a formal assessment of safety. To meet this need a system was proposed for a pre-market safety assessment of selected groups of microorganisms leading to a “Qualified Presumption of Safety (QPS)”. In essence this proposed that a safety assessment of a defined taxonomic group (e.g. genus or group of related species) could be made based on four pillars (establishing identity, body of knowledge, possible pathogenicity and end use). If the taxonomic group did not raise safety concerns or, if safety concerns existed, but could be defined and excluded (the qualification) the grouping could be granted QPS status. Thereafter, any strain of microorganism the identity of which could be unambiguously established and assigned to a QPS group would be freed from the need for further safety assessment other than satisfying any qualifications specified. Microorganisms not considered suitable for QPS would remain subject to a full safety assessment. EFSA asked its Scientific Committee to consider whether this system could be used to harmonise approaches to the safety assessment of microorganisms across the various EFSA scientific panels. If so, the Committee was requested to develop a strategy for the introduction of an assessment system based on the QPS concept.

Introduction of a Qualified Presumption of Safety (QPS) approach for assessment of selected microorganisms referred to EFSA 1 Opinion of the Scientific Committee

Recent shift in trends of agricultural practices from application of synthetic fertilizers and pesticides to organic farming has brought into focus the use of microorganisms that carryout analogous function. Trichoderma spp. is one of the most popular genera of fungi commercially available as a plant growth promoting fungus (PGPF) and biological control agent. Exploitation of the diverse nature of secondary metabolites produced by different species of Trichoderma augments their extensive utility in agriculture and related industries. As a result, Trichoderma has achieved significant success as a powerful biocontrol agent at global level. The endorsement of Trichoderma spp. by scientific community is based on the understanding of its mechanisms of action against a large set of fungal, bacterial and in certain cases viral infections. However, it is still an agnostic view that there could be any single major mode of operation, although it is argued that all mechanisms operate simultaneously in a synchronized fashion. The central idea behind this review article is to emphasize the potentiality of applications of target specific secondary metabolites of Trichoderma for controlling phytopathogens as a substitute of commercially available whole organism formulations. With the aim to this point, we have compiled an inclusive list of secondary metabolites produced by different species of Trichoderma and their applications in diverse areas with the major emphasis on agriculture. Outlining the importance and diverse activities of secondary metabolites of Trichoderma besides its relevance to agriculture would generate greater understanding of their other important and beneficial applications apart from target specific biopesticides.

Unraveling the efficient applications of secondary metabolites of various Trichoderma spp.

Vertinoid Polyketides from the Saltwater Culture of the Fungus Trichoderma longibrachiatum Separated from a Haliclona Marine Sponge

The marine sponge Diacarnus cf. spinopoculum has provided a series of norterpenes, including five new compounds (7-11), two new ent-compounds [(-)-1a and (+)-1b], and three known compounds (2a, 2b, and 12). Eight of these compounds represent additional examples of the muqubilin/sigmosceptrellin classes (norsesterterpene peroxides) or the nuapapuin class (norditerpene peroxides). Also isolated were dinorditerpenones 11 and 12, which are biosynthetically related to the muqubilin/sigmosceptrellin structure classes. In all, 11 compounds were evaluated for their cytotoxic properties using a soft agar assay system and the NCI's 60 cell-line screen. Compounds without peroxide functionality were inactive. Overall, the norsesterterpene peroxides were less selective as cytotoxins than norditerpene peroxide analogues. Two compounds, nuapapuin A methyl ester (3) and nuapapuin B (7), which were somewhat selective in their cytotoxic behavior, were selected for further in vivo evaluation.

Isolation and cytotoxic evaluation of marine sponge-derived norterpene peroxides

Two steroids, haliclostanone sulfate (1) and halistanol sulfate (3), were isolated from a Haliclona sp. marine sponge. The structure of the new compound 1 was established based on its spectroscopic data and the properties of a pentaacetate derivative 2. Compound 1 is unique in that it possesses the rare cis C/D ring junction precedented only in marine sterols, contignasterol (4) and xestobergsterols A (5), B (6), and C (7).

Haliclostanone Sulfate and Halistanol Sulfate from an Indo-Pacific Haliclona Sponge

The saltwater culture of a Paecilomyces cf. javanica isolated from the marine sponge Jaspis cf. coriacea has yielded a new polyketide, deoxynortrichoharzin (1), and two known diketopiperazines (2 and 3).

Sam Sperry

Papers

Vertinoid Polyketides from the Saltwater Culture of the Fungus Trichoderma longibrachiatum Separated from a Haliclona Marine Sponge

Isolation and cytotoxic evaluation of marine sponge-derived norterpene peroxides

Haliclostanone Sulfate and Halistanol Sulfate from an Indo-Pacific Haliclona Sponge

Deoxynortrichoharzin, a new polyketide from the saltwater culture of a sponge-derived Paecilomyces fungus.

Vertinoid Polyketides from the Saltwater Culture of the Fungus Trichoderma longibrachiatum Separated from a Haliclona Marine Sponge.