Characterization of the Key Bibenzyl Synthase in Dendrobium sinense

Abstract

Dendrobium sinense, an endemic medicinal herb in Hainan Island, is rich in bibenzyls. However, the key rate-limited enzyme involved in bibenzyl biosynthesis has yet to be identified in D. sinense. In this study, to explore whether there is a significant difference between the D. sinense tissues, the total contents of bibenzyls were determined in roots, pseudobulbs, and leaves. The results indicated that roots had higher bibenzyl content than pseudobulbs and leaves. Subsequently, transcriptomic sequencings were conducted to excavate the genes encoding type III polyketide synthase (PKS). A total of six D. sinense PKS (DsPKS) genes were identified according to gene function annotation. Phylogenetic analysis classified the type III DsPKS genes into three groups. Importantly, the c93636.graph_c0 was clustered into bibenzyl synthase (BBS) group, named as D. sinense BBS (DsBBS). The expression analysis by FPKM and RT-qPCR indicated that DsBBS showed the highest expression levels in roots, displaying a positive correlation with bibenzyl contents in different tissues. Thus, the recombinant DsBBS-HisTag protein was constructed and expressed to study its catalytic activity. The molecular weight of the recombinant protein was verified to be approximately 45 kDa. Enzyme activity analysis indicated that the recombinant DsBBS-HisTag protein could use 4-coumaryol-CoA and malonyl-CoA as substrates for resveratrol production in vitro. The Vmax of the recombinant protein for the resveratrol production was 0.88 ± 0.07 pmol s−1 mg−1. These results improve our understanding with respect to the process of bibenzyl biosynthesis in D. sinense.

Non-Protein Thiol Compounds and Antioxidant Responses Involved in Bryophyte Heavy-Metal Tolerance

“…The synthesis of lunularic acid starts from phenylalanine [ 75 ]. Thus, this compound might be a by-product of the activation of the flavonoid biosynthesis via the phenylpropanoid pathway [ 76 ] or be actively involved in the antioxidant response. To date, the role of bibenzyls in stress response to heavy metals has not yet been ascertained.…”

Detection of a bibenzyl core scaffold in 28 common mangrove and associate species of the Indian Sundarbans: potential signature molecule for mangrove salinity stress acclimation

“…(33 species) from Thailand, detected by HPLC, the total bibenzyl derivative content ranged from the highest level of 7.36 ± 0.50 mg/g dry weight in D. fimbriatum to the lowest level of 0.07 ± 0.00 mg/g dry weight in D. christyanum among all 33 species ( Choonong et al., 2019 ). The total bibenzyl content from the dried roots, pseudobulbs, and leaves of Dendrobium sinense , measured via spectrophotometry using bibenzyl gigantol as a standard was reported to be 1.31%, 0.62%, and 0.72% respectively of the dry weight of roots, pseudobulbs, and leaves ( Chen et al., 2022 ).…”

“…The main finding of a bibenzyl molecule detected in 28 mangrove species through this extensive GC-MS and GC-FID study initially seemed to be very intriguing. To date, among plants, bibenzyl derivatives have mainly been reported from some bryophytes, orchids, and Cannabis sativa , and some of these derivatives are well established for several clinical parameters, mainly based on their antimicrobial and cytotoxic potential ( Nandy and Dey, 2020 ; Ahmad et al., 2022 ; Boddington et al., 2022 ; Chen et al., 2022 ). Several mangrove and mangrove associate species are often reported to possess bioactive secondary metabolite molecules of high curative, preventive, and pharmaceutical importance in medicinal practices ( Bandaranayake, 1998 ; Jiang et al., 2018 ; Zhang et al., 2018 ; Bibi et al., 2019 ; Roy and Dutta, 2021 ; Sudhir et al., 2022 ; Wu et al., 2022 ).…”

“…One group of such secondary metabolites with a common “bibenzyl” core structure has been widely reported in plants, which is considered to possess varying therapeutic attributes ( Nandy and Dey, 2020 ; Ahmad et al., 2022 ; Boddington et al., 2022 ; Chen et al., 2022 ). Bibenzyls have a common parent nucleus consisting of two benzene rings as a derivative of ethane (C6-C2-C6) ( Figure 1A ) with different substituent groups ( Zhang et al., 2007 ; Nandy and Dey, 2020).…”

Major Active Metabolite Characteristics of Dendrobium officinale Rice Wine Fermented by Saccharomyces cerevisiae and Wickerhamomyces anomalus Cofermentation

“…Astragalosides have a wide range of biological activities. Moreover, resveratrol is an important active component of D. officinale with anticancer activities [ 27 , 28 ].…”