Nitric Oxide Mediates the Fungal Elicitor-Induced Hypericin Production of Hypericum perforatum Cell Suspension Cultures through a Jasmonic-Acid-Dependent Signal Pathway

Abstract

Fungal elicitor prepared from the cell walls of Aspergillum niger induces multiple responses of Hypericum perforatum cells, including nitric oxide (NO) generation, jasmonic acid (JA) biosynthesis, and hypericin production. To determine the role of NO and JA in elicitor-induced hypericin production, we study the effects of NO scavenger 2-to 4-carboxyphenyl-4,4, 5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPITO), nitric oxide synthase inhibitor S,S#-1,3-phenylene-bis(1,2-ethanediyl)-bis-isothiourea, and inhibitors of the octadecanoid pathway on elicitor-induced NO generation, JA biosynthesis, and hypericin production. Pretreatment of the cells with cPITO and JA biosynthesis inhibitors suppresses not only the elicitor-induced NO generation and JA accumulation but also the elicitor-induced hypericin production, which suggests that both NO and JA are involved in elicitor-induced hypericin biosynthesis. S,S#-1,3-phenylene-bis(1,2-ethanediyl)-bis-isothiourea and cPITO inhibit both elicitor-induced NO generation and JA biosynthesis, while JA biosynthesis inhibitors do not affect the elicitor-induced NO generation, indicating that JA acts downstream of NO generation and that its biosynthesis is regulated by NO. External application of NO via its donor sodium nitroprusside induces hypericin production in the absence of fungal elicitor. Sodiumnitroprusside-induced hypericin production is blocked by JA biosynthesis inhibitors, showing that JA biosynthesis is essential for NO-induced hypericin production. The results demonstrate a causal relationship between elicitor-induced NO generation, JA biosynthesis, and hypericin production in H. perforatum cells and indicate a sequence of signaling events from NO to hypericin production, within which NO mediates the elicitor-induced hypericin biosynthesis at least partially via a JA-dependent signaling pathway.

Nitric oxide mediates the fungal-elicitor-enhanced biosynthesis of antioxidant polyphenols in submerged cultures of Inonotus obliquus

“…These are widely reported putative components of signal transduction chain(s) leading to elicitor-induced defence responses, which include activation of defence genes, hypersensitive cell death and systemic acquired resistance (Baker & Orlandi, 1995). The molecular basis of these defence responses is believed to involve signal transductions by nitric oxide via a jasmonic acid-dependent signalling pathway and eventually biosynthesis of secondary metabolites (Xu et al, 2005). However, relatively little is known about fungalelicitor-induced increases in production of phenolic compounds and their mechanism of action.…”

Enhanced production of valerenic acid in hairy root culture of Valeriana officinalis by elicitation

“…This substantial effect of FE has also been reported for podophyllotoxin production in suspension culture of Linum album [19]. Accumulation of JA and its derivatives, such as methyl jasmonate (MJ) is one of the common responses of plant cells to fungal elicitors and as intermediate signals in elicitor-induced secondary metabolite accumulation in plant cells [39]. Few studies refer to the plant secondary metabolism mediated by the fungal elicitor.…”

Nitric oxide counters ethylene effects on ripening fruits

“…Inhibition of wound induced H 2 O 2 production and synthesis of proteinase inhibitor in tomato leaves were found to be mediated by both NO and JA. 68 NO influences the JA-regulated induction of hypericin production in cell cultures of Hypericum perforatum following the addition of a fungal elicitor 69 and JA caused a burst of NO during wound healing in Arabidopsis. 59 Thus, both NO and JA were found to act synergistically in cellular stress responses as well as wound healing.…”