Stilbenoid prenyltransferases define key steps in the diversification of peanut phytoalexins

Abstract

Defense responses of peanut () to biotic and abiotic stresses include the synthesis of prenylated stilbenoids. Members of this compound class show several protective activities in human disease studies, and the list of potential therapeutic targets continues to expand. Despite their medical and biological importance, the biosynthetic pathways of prenylated stilbenoids remain to be elucidated, and the genes encoding stilbenoid-specific prenyltransferases have yet to be identified in any plant species. In this study, we combined targeted transcriptomic and metabolomic analyses to discover prenyltransferase genes in elicitor-treated peanut hairy root cultures. Transcripts encoding five enzymes were identified, and two of these were functionally characterized in a transient expression system consisting of-infiltrated leaves of We observed that one of these prenyltransferases, AhR4DT-1, catalyzes a key reaction in the biosynthesis of prenylated stilbenoids, in which resveratrol is prenylated at its C-4 position to form arachidin-2, whereas another, AhR3'DT-1, added the prenyl group to C-3' of resveratrol. Each of these prenyltransferases was highly specific for stilbenoid substrates, and we confirmed their subcellular location in the plastid by fluorescence microscopy. Structural analysis of the prenylated stilbenoids suggested that these two prenyltransferase activities represent the first committed steps in the biosynthesis of a large number of prenylated stilbenoids and their derivatives in peanut. In summary, we have identified five candidate prenyltransferases in peanut and confirmed that two of them are stilbenoid-specific, advancing our understanding of this specialized enzyme family and shedding critical light onto the biosynthesis of bioactive stilbenoids.

Impact of Environmental Factors on Stilbene Biosynthesis

“…Over 45 prenylated stilbenoids have been identified in A. hypogaea [148]. The major prenylated stilbenoids accumulated in peanuts are trans-arachidin-1, trans-arachidin-2, trans-arachidin-3, and trans-3 -(3-methyl-2-butenyl)-resveratrol ( Figure 7) [148].…”

“…Over 45 prenylated stilbenoids have been identified in A. hypogaea [148]. The major prenylated stilbenoids accumulated in peanuts are trans-arachidin-1, trans-arachidin-2, trans-arachidin-3, and trans-3 -(3-methyl-2-butenyl)-resveratrol ( Figure 7) [148]. In accordance with their role as phytoalexins, peanut prenylated stilbenoids have been shown to accumulate upon challenge with microorganisms [142][143][144][145]149] and to possess remarkable antifungal activity [150][151][152].…”

Production of Prenylated Stilbenoids in Hairy Root Cultures of Peanut (Arachis hypogaea) and Its Wild Relatives A. ipaensis and A. duranensis via an Optimized Elicitation Procedure

“…A comparison of the profile of specialized metabolites between the cultivated peanut and its ancestors would provide useful information to elucidate their biosynthesis. Hairy roots of cultivated peanut have been successfully applied not only as a bioproduction platform for prenylated stilbenoids, but for characterization of new genes involved in the biosynthesis of these valuable compounds [16]. Thus, in the present work, hairy root cultures of the wild Arachis species A. duranensis and A. ipaensis were developed and treated with optimized elicitation conditions for prenylated stilbenoid profiling.…”

Biotechnological Advances in Resveratrol Production and its Chemical Diversity

“…Furthermore, Yang and coworkers (2017) have observed the C-prenylation on resveratrol or stilbenoids at the 4- and 3′-position by the help of the enzymes AhR4DT-1 and AhR3′DT-1 which were obtained from Arachis hypogaea (Figure 3). Such prenylated stilbenoids have shown very effective protective activities in human diseases as well [153]. Similar prenylated resveratrol compounds at the position 3′-, were also with the enzyme NovQ, obtained from Streptomyces spheroids [154,155].…”