The regulatory mechanism of fungal elicitor-induced secondary metabolite biosynthesis in medical plants

Abstract

A wide range of external stress stimuli trigger plant cells to undergo complex network of reactions that ultimately lead to the synthesis and accumulation of secondary metabolites. Accumulation of such metabolites often occurs in plants subjected to stresses including various elicitors or signal molecules. Throughout evolution, endophytic fungi, an important constituent in the environment of medicinal plants have known to form long-term stable and mutually beneficial symbiosis with medicinal plants. The endophytic fungal elicitor can rapidly and specifically induce the expression of specific genes in medicinal plants which can result in the activation of a series of specific secondary metabolic pathways resulting in the significant accumulation of active ingredients. Here we summarize the progress made on the mechanisms of fungal elicitor including elicitor signal recognition, signal transduction, gene expression and activation of the key enzymes and its application to this process. This paper provides guidance on studies which may be conducted to promote the efficient synthesis and accumulation of active ingredients by the endogenous fungal elicitor in medicinal plant cells, and provides new ideas and methods of studying the regulation of secondary metabolism in medicinal plants.

Fungal endophytes promote the accumulation of Amaryllidaceae alkaloids in Lycoris radiata

“…In this study, the effects of different fungal endophytes on the accumulation of alkaloids in L. radiata were quite different (Fig. 7); this may be because the mechanisms underlying the accumulation of secondary metabolites induced by fungal endophytes could depend on the endophyte and/or plant species (Zhai et al, 2017). Diverse fungal elicitors could be recognized by pattern recognition receptors on plant cell membranes and then different signalling cascades would be activated, which will further enhance secondary metabolite synthesis (Hao et al, 2010;Yuan et al, 2016b;Zhai et al, 2017).…”

“…7); this may be because the mechanisms underlying the accumulation of secondary metabolites induced by fungal endophytes could depend on the endophyte and/or plant species (Zhai et al, 2017). Diverse fungal elicitors could be recognized by pattern recognition receptors on plant cell membranes and then different signalling cascades would be activated, which will further enhance secondary metabolite synthesis (Hao et al, 2010;Yuan et al, 2016b;Zhai et al, 2017). Since we observed that some fungal endophytes promoted the accumulation of alkaloids, not only in the organ where they had been originally isolated but also in other organs of L. radiata (Table S3), the results indicate that the fungal colonization was involved in initiating certain long-distance signalling cascades, which later regulated the alkaloid synthesis in other locations.…”

“…Actually, plant defensive responses are aroused by perceiving fungal endophytes (Camehl et al, 2010;Yuan et al, 2019). Then, the activated signalling elements, such as reactive oxygen species and phytohormones, trigger the downstream synthetic pathways of secondary metabolites in planta (Yuan et al, 2016b;Zhai et al, 2017). These bioactive secondary metabolites can regulate the growth of fungal endophytes, which help symbiotic interactions to be maintained (Liu and Reinscheid, 2004;Schulz and Boyle, 2005).…”

Biodiversity in targeted metabolomics analysis of filamentous fungal pathogens by 1H NMR-based studies

“…Generally, fungi are capable of producing different secondary metabolites such as antibiotics, volatile compounds and others, which is related to the activation of different metabolic pathways involving the biosynthetic precursors of these reactions (Zhai et al 2017; Alberti et al 2017). In G. can , the levels of histidine and xanthine, the main precursor metabolites in the biosynthesis of secondary metabolites, were elevated.…”

The Pharmacological Effects of Triterpenoids from <i>Ganoderma lucidum</i> and the Regulation of Its Biosynthesis

“…There are already many reports focusing on the crosstalk among ET, JA and SA signalling pathways, but the knowledge about crosstalk among these plant hormones in G. lucidum is very limited [57]. Therefore, more research about hormonal crosstalk in G. lucidum might open up perspectives to manipulate the biosynthesis of GA.…”