Nitric oxide mediates hypocrellin accumulation induced by fungal elicitor in submerged cultures of Shiraia bambusicola.

Multiple responses of Shiraia bambusicola, including nitric oxide (NO) generation, hypocrellins production and salicylic acid (SA) biosynthesis, were induced by a fungal elicitor prepared from the mycelium of Aspergillum niger. Both the NO donator, sodium nitroprusside, and SA enhanced hypocrellin production without the fungal elicitor. However, the NO scavenger, 2,4-carboxyphenyl-4,4, 5,5- tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) and the SA biosynthesis inhibitor, cinnamic acid (CA), inhibited hypocrellin accumulation in the presence of the elicitor. cPTIO also inhibited SA production induced by the A. niger elicitor. CA failed to inhibit NO production but it significantly inhibited hypocrellin accumulation. Aspergillum niger elicitor induced an NO burst, SA accumulation, and hypocrellin production in S. bambusicola. Therefore, the fungal elicitor was involved in the signaling pathway, which is a mechanism different from that of higher plants.