Fungal endophytes: unique plant inhabitants with great promises

Abstract

Fungal endophytes residing in the internal tissues of living plants occur in almost every plant on earth from the arctic to the tropics. The endophyte-host relationship is described as a balanced symbiotic continuum ranging from mutualism through commensalism to parasitism. This overview will highlight selected aspects of endophyte diversity, host specificity, endophyte-host interaction and communication as well as regulation of secondary metabolite production with emphasis on advanced genomic methods and their role in improving our current knowledge of endophytic associations. Furthermore, the chemical potential of endophytic fungi for drug discovery will be discussed with focus on the detection of pharmaceutically valuable plant constituents as products of fungal biosynthesis. In addition, selected examples of bioactive metabolites reported in recent years (2008-2010) from fungal endophytes residing in terrestrial plants are presented grouped according to their reported biological activities.

Camptothecin-producing endophytic fungus Trichoderma atroviride LY357: isolation, identification, and fermentation conditions optimization for camptothecin production

“…The CPT-producing capability of LY341 and LY355 was completely lost after repeat subculturing under axenic monoculture conditions, which is consistent with previous reports (Kusari et al 2009;Gurudatt et al 2010) and supports that the biosynthetic genes of CPT horizontally transferred from the host were mutated randomly, unpredictably, and nonsynonymously with subculturing . The findings of this work are consistent with previous hypotheses that (1) during the course of evolution, the endophytes developed machinery and survived in association with the medicinal plants (Gurudatt et al 2010), and (2) the patchy distribution of CPT in different plants was suggested to be caused by endophyte infection to the corresponding plants and subsequent gene transfer (Aly et al 2011).…”

“…Endophytes resided in the internal tissues of living plants occur in almost every plant on earth from the arctic to the tropics, and they are rich sources for bioactive natural products (Guo et al 2008;Aly et al 2010Aly et al , 2011Qin et al 2011). It is generally recognized that endophytes represent an important and largely untapped reservoir of unique chemical structures that have been modified through evolution (Gunatilaka 2006;Kharwar et al 2011) and exhibit the capability to produce the same functional compounds as their hosts, some examples include taxol (Stierle et al 1993(Stierle et al , 1995, podophyllotoxin , hypericin (Kusari et al 2008), and azadirachtin (Findlay et al 1997).…”

A twist of nature – the significance of atropisomers in biological systems

“…Lesser-investigated sources of bioactive molecules are endophytic fungi that reside within both plants and marine species. 28 It was recently discovered by Bara et al that the Talaromyces wortmannii fungus, an endosymbiont of Egyptian Aloe vera (Asphodeloideae), contained several bioactive atropisomeric compounds; and the group conducted extremely extensive studies to determine any potential medicinal application. 29 Analysis of the isolated products 26 found that they were similar to that of previously-reported flavomannin, 30 allowing for general structural assignment ( Figure 5, Compounds 11 and 12).…”

Antimicrobial activities of endophytic fungi of the Sri Lankan aquatic plantNymphaea nouchaliand chaetoglobosin A and C, produced by the endophytic fungusChaetomium globosum

“…Despite the cryptic nature of their symbiotic existence in host plants they have gained recognition as prolific producers of secondary metabolites that have potential in medical and agricultural applications useful to mankind (Aly et al 2011). However, much of the Earth’s endophytic fungal population, estimated to be in the millions, remains uninvestigated in this respect, making this an exciting frontier for useful discoveries (Cowell 2002).…”