Recent progress in biodiversity research on the Xylariales and their secondary metabolism

Abstract

The families Xylariaceae and Hypoxylaceae (Xylariales, Ascomycota) represent one of the most prolific lineages of secondary metabolite producers. Like many other fungal taxa, they exhibit their highest diversity in the tropics. The stromata as well as the mycelial cultures of these fungi (the latter of which are frequently being isolated as endophytes of seed plants) have given rise to the discovery of many unprecedented secondary metabolites. Some of those served as lead compounds for development of pharmaceuticals and agrochemicals. Recently, the endophytic Xylariales have also come in the focus of biological control, since some of their species show strong antagonistic effects against fungal and other pathogens. New compounds, including volatiles as well as nonvolatiles, are steadily being discovered from these ascomycetes, and polythetic taxonomy now allows for elucidation of the life cycle of the endophytes for the first time. Moreover, recently high-quality genome sequences of some strains have become available, which facilitates phylogenomic studies as well as the elucidation of the biosynthetic gene clusters (BGC) as a starting point for synthetic biotechnology approaches. In this review, we summarize recent findings, focusing on the publications of the past 3 years.

Fig. 1

Stromata of some tropical and subtropical species of Xylariales. a Xylaria melanura. b X. telfairii. c X. grammica. d Hypoxylon haematostroma. e Pyrenopolyporus hunteri. f H. griseobrunneum. Images were kindly provided by Esteban B. Sir

Fig. 2

Secondary metabolites recently described from the genera Amphirosellinia, Ascotricha, Dematophora, Nemania, and Stromatoneurospora

Fig. 3

Recently reported cytochalasans from Xylaria spp.

Fig. 4

Recently reported terpenoids and terpenoid-hybrids from Xylaria spp.

Fig. 5

Recently reported non-ribosomal peptides from Xylaria spp.

Fig. 6

Recently reported macrolides from Xylaria spp.

Fig. 7

Recently reported benzenoids and lactones from Xylaria spp.

Fig. 8

Recently reported miscellaneous secondary metabolites from Xylaria spp.

Fig. 9

Recently reported cytochalasans from species of the Hypoxylaceae

Fig. 10

Recently reported azaphilones from species of the Hypoxylaceae

Fig. 11

Recently reported terpenoids/hybrid-terpenoids from species of the Hypoxylaceae

Fig. 12

Recently reported macrolides from species of the Hypoxylaceae

Fig. 13

Recently reported benzenoids, lactones, and other small cyclic molecules from species of the Hypoxylaceae

Fig. 14

Recently reported miscellaneous secondary metabolites from species of the Hypoxylaceae

Fig. 15

Some prominent secondary metabolites from members of Xylariales