Secondary metabolites of fungal vine pathogens

Abstract

Fungi are highly diverse organisms in terms of their lifestyle and habitats. This high diversity is reflected by the structural diversity and the large number of metabolites produced. The so-called secondary metabolites have been described as compounds not required for either the vitality of an organism or primary metabolic processes (Karlovsky 2008). Such compounds have in the past been of enormous interest due to their potential as lead structures for human therapeutics and plant protectants. More than 50% of all the human therapeutics on the market today either are natural products or are structurally related to secondary metabolites of plant or microbial origin. Recent assumptions are indicating that more than half of 1500 compounds isolated between 1993 and 2001 had antimicrobial or antitumor activity (Keller et al. 2005). Even though many of these secondary metabolites were found to have beneficial biological activities, mycotoxins are deleterious due to their impact within the food chain. In many cases, bioactive low-molecular-weight secondary metabolites were found to be produced as structurally closely related compounds in distinct parts of the life cycle of the producing organism. The biosynthesis of these compounds is often correlated with a specific stage of morphological differentiation (Martín et al. 2014). Furthermore, a restricted taxonomic distribution of such metabolites has inspired chemotaxonomy. Nevertheless investigations into natural product research concerning the biosynthetic potential of producing organisms are often hampered by the fact that production of these metabolites is sensitive to culture conditions (Weinberg 1974). Therefore, the metabolites produced in axenic culture do not match the spectrum of natural products produced within the environment.