Plants and endophytes: equal partners in secondary metabolite production?

Abstract

Well known plant production systems should be re-evaluated due to findings that the interesting metabolite might actually be produced by microbes intimately associated with the plant, so-called endophytes. Endophytes can be bacteria or fungi and they are characterized usually by the feature that they do not cause any harm to the host. Indeed, in some cases, such as mycorrhizal fungi or other growth promoting endophytes, they can be beneficial for the plant. Here some examples are reviewed where the host plant and/or endophyte metabolism can be induced by the other partner. Also, partial or complete biosynthesis pathways for plant secondary metabolites can be attributed to such endophytes. In other cases the host plant is able to metabolize substances from fungal origin. The question of the natural role of such metabolic changes for the endophyte will be briefly touched. Finally, the consequences for the use of plant cultures for secondary metabolite production is discussed.

Isolation, identification and bioactivity of fungal endophytes from selected Kenyan medicinal plants

“…Secondary metabolite production by endophytes is primarily linked to reducing competition from other microorganisms within the host plants. Further, the production of these natural products defends both the host plant and endophytes from disease-causing microorganisms (Ludwig-Müller, 2015). The bioactivity displayed by extracts from the fungal endophytes in this study could contribute to the medicinal properties of the medicinal plants.…”

A glimpse of the endophytic bacterial diversity in roots of blackberry plants (Rubus fruticosus)

“…These three genera have also been detected as endophytes in the roots of Mexican husk tomato plants (Physalis ixocarpa Brot.) by Márquez-Santacruz et al (2010), and as regular microbiota in many other plant hosts (Li et al, 2015;Ludwig-Müller, 2015;Sheibani-Tezerji et al, 2015).…”

A Novel Strain of Pantoea Eucrina Endophyte of Murraya Koenigii With Squalene Cyclase Activity

“…CATDLF5 and Choanephora infundibulifera CATDLF6 isolated from the leaves of the plant were found to enhance vindoline production by modulating the expression of key structural and regulatory genes of vindoline biosynthesis without affecting the primary metabolism of the host plant (Pandey et al, 2016). Plant endophyte metabolism can interact on any levels: (a) the endophyte induces host metabolism, (b) the host induces endophyte metabolism, (c) host and endophyte share parts of a specific pathway and contribute partially (d) the host can metabolize products from the endophyte and vice versa (e) the endophyte can metabolize secondary compounds from the host (Ludwig-Müller 2015). Studies on squalene hopene cyclases from different bacterial systems and its structural and functional aspects are being carried out across the globe.…”