The Diversity of Anti-Microbial Secondary Metabolites Produced by Fungal Endophytes: An Interdisciplinary Perspective

Abstract

Endophytes are microbes that inhabit host plants without causing disease and are reported to be reservoirs of metabolites that combat microbes and other pathogens. Here we review diverse classes of secondary metabolites, focusing on anti-microbial compounds, synthesized by fungal endophytes including terpenoids, alkaloids, phenylpropanoids, aliphatic compounds, polyketides, and peptides from the interdisciplinary perspectives of biochemistry, genetics, fungal biology, host plant biology, human and plant pathology. Several trends were apparent. First, host plants are often investigated for endophytes when there is prior indigenous knowledge concerning human medicinal uses (e.g., Chinese herbs). However, within their native ecosystems, and where investigated, endophytes were shown to produce compounds that target pathogens of the host plant. In a few examples, both fungal endophytes and their hosts were reported to produce the same compounds. Terpenoids and polyketides are the most purified anti-microbial secondary metabolites from endophytes, while flavonoids and lignans are rare. Examples are provided where fungal genes encoding anti-microbial compounds are clustered on chromosomes. As different genera of fungi can produce the same metabolite, genetic clustering may facilitate sharing of anti-microbial secondary metabolites between fungi. We discuss gaps in the literature and how more interdisciplinary research may lead to new opportunities to develop bio-based commercial products to combat global crop and human pathogens.

Adaptive Cellular Stress Pathways as Therapeutic Targets of Dietary Phytochemicals: Focus on the Nervous System

“…Much as we live with commensal microorganisms (bacteria and fungi) on our skin and in our gut (Kamada et al, 2013;Schommer and Gallo, 2013), higher plants coexist with fungi and bacteria that live among their cells (Reinhold-Hurek and Hurek, 2011;Mousa and Raizada, 2013). Although many phytochemicals are produced by plant cells, others are produced by the fungi or bacteria that live within the plant (Bascom-Slack et al, 2012).…”

Root-hair endophyte stacking in finger millet creates a physicochemical barrier to trap the fungal pathogen Fusarium graminearum

“…However, the emerging literature suggests that microbes that inhabit plants without themselves causing disease, defined as endophytes, may contribute to host resistance against fungal pathogens 11,12 . Endophytes suppress diseases through the induction of host resistance genes 13 , competition 14 and/or the production of antipathogenic compounds 15,16 .…”

Isolation and Identification of Three Bioactive Compounds from Endophytic Fungus Trichoderma sp.

“…One endophytic isolate showed an activity against tested bacteria which was Trichoderma sp. Endophytic fungi are a good source for antimicrobial products [16]. Endophytes are reported as novel source of antimicrobial compounds [17].…”