21.06.2022

Piperine biosynthesis: all in one place.

Piperine is an alkaloid responsible for the pungency of pepper (Piper nigrum), more precisely, of its black dried fruits. In recent years, IPB scientists have successfully elucidated the biosynthesis of piperine (news tickers #20, #66, #80). The final step of this synthesis is catalyzed by piperine synthase, which catalyzes the reaction of piperoyl-CoA and piperidine to form the biologically active and pungent amide. Until now, it was not known whether the enzyme and reaction product co-localize in the fruits or whether there is a subsequent transport of the piperine to the fruit and other tissues. Now, IPB scientists have shown that both piperine synthase and its product, piperine, accumulate in fruits during the early stages of their development. Since piperine fluoresces bluish under UV light, the researchers were able to use this intrinsic fluorescence to identify the cells containing piperine. Using this method and typical immunolocalization methods, they found that piperine and piperine synthase are present in specialized cells of the pepper fruit perisperm. With laser microdissection, they isolated the cells, examined them by LC-ESI/MS, and were able to estimate that piperine was present in surprisingly high concentrations of about 4 molar. Piperine and related piperidine alkaloids were also detectable in the cortex of root cells - possibly a defense against biotic stressors. In the future, the localization of further upstream steps of piperine biosynthesis needs to be elucidated.

Original publication: Jäckel, L., Schnabel, A., Stellmach, H., Klauß, U., Matschi, S., Hause, G. and Vogt, T. (2022). The terminal enzymatic step in piperine biosynthesis is co-localized with the product piperine in specialized cells of black pepper (Piper nigrum L.). Plant J. Accepted Author Manuscript. https://doi.org/10.1111/tpj.15847