RgC3H Involves in the Biosynthesis of Allelopathic Phenolic Acids and Alters Their Release Amount in Rehmannia glutinosa Roots

Abstract

Rehmannia glutinosa production is affected by replanting disease, in which autotoxic harm to plants is mediated by endogenous phenolic acids as allelopathic compounds found in root exudates. These phenolic acids are mostly phenylpropanoid products of plants’ secondary metabolisms. The molecular mechanism of their biosynthesis and release has not been explored in R. glutinosa. P-coumarate-3-hydroxylase (C3H) is the second hydroxylase gene involved in the phenolic acid/phenylpropanoid biosynthesis pathways. C3Hs have been functionally characterized in several plants. However, limited information is available on the C3H gene in R. glutinosa. Here, we identified a putative RgC3H gene and predicted its potential function by in silico analysis and subcellular localization. Overexpression or repression of RgC3H in the transgenic R. glutinosa roots indicated that the gene was involved in allelopathic phenolic biosynthesis. Moreover, we found that these phenolic acid release amount of the transgenic R. glutinosa roots were altered, implying that RgC3H positively promotes their release via the molecular networks of the activated phenolic acid/phenylpropanoid pathways. This study revealed that RgC3H plays roles in the biosynthesis and release of allelopathic phenolic acids in R. glutinosa roots, laying a basis for further clarifying the molecular mechanism of the replanting disease development.

Visualizing the spatial distribution and alteration of metabolites in continuously cropped Salvia miltiorrhiza Bge using MALDI-MSI

“…5 C, [M−H] − , m/z 717.1) in continuously cropped SMB were much lower than those in normal SMB. Low-molecular-weight phenolic acids have been reported to be a class of plant autotoxic compounds that can cause diseases in continuously cropped plants [ 35 , 36 ]. Three low-molecular-weight phenolic acids, namely, ferulic acid ( Fig.…”

A Rehmannia glutinosa caffeic acid O‐methyltransferase functional identification: Reconstitution of the ferulic acid biosynthetic pathway in Saccharomyces cerevisiae using Rehmannia glutinosa enzymes

“…The supernatant was collected, dried, resuspended in 1 mL methanol, and filtrated using a 0.22‐µm filter for HPLC analysis as mentioned previously. [ 2 ] Three replicates were performed for each experiment.…”

“…[ 3,4 ] In addition to glycoside compounds such as acteoside and catalpol, R. glutinosa also contains a large group of phenolics with strong biological activity, including ferulic acid (4‐hydroxy‐3‐methoxycinnamic acid, FA). [ 2,5 ] Especially, FA is an important precursor of some medicinal ingredients, such as coumarins, curcuminoids, vanillins, and lignans, [ 5–9 ] which can exhibit a wide range of biomedical effects, including antioxidant, free radical scavenging, anti‐inflammatory, and antiviral activities. [ 5–8 ] As the FA production in plants including R. glutinosa occurs at low efficiency, [ 2,9 ] it is very significant to explore the FA biosynthesis pathways for enhancing the production of FA and its derivations.…”

“…[9][10][11] In the FA biosynthesis pathway from Phe metabolism, Phe is thought to initially be converted into cinnamic acid (CiA) via the catalysis of phenylalanine ammonia-lyase (PAL), and then CiA and p-coumaric acid (p-CA) are, respectively, converted into p-CA and caffeic acid (CA) by C4H and C3H hydroxylation; finally, CA is converted into FA by the catalysis of caffeic acid 3-O-methyltransferase (COMT), which belongs to the Sadenosyl-L-methionine (SAM)-dependent O-methyltransferase family (Figure S1). [9,12] In R. glutinosa, although the three R. glutinosa catalytic enzymes (RgPALs, RgC4H, and RgC3H) involved in FA biosynthesis from Phe metabolism have been identified and functionally characterized, [2,4,13] to date, COMT genes and proteins, which are vital catalytic enzymes involved in FA biosynthesis, have not been characterized and verified in this species. Moreover, there are several reports concerning the identification and functional characterization of some plant COMTs that have been revealed to exhibit typical Omethyltransferase activity, thus catalyzing the conversion of CA into FA.…”

The Effects of NAA on the Tuberous Root Yield and Quality of Rehmannia glutinosa and Its Regulatory Mechanism by Transcriptome and Metabolome Profiling

“…So far, exogenous NAA has been used to increase plant yield, such as in rice and strawberries [ 11 , 12 ], as well as in changing strawberry metabolites [ 13 ]. NAA was also used in R. glutinosa tissue culture and genetic transformation for many years, improving R. glutinosa rooting or callus and adventitious root induction and shoot differentiation, by itself or in combination with other PGRs [ 14 , 15 ]. Moreover, the effect of a swelling agent (Ligenwei), containing 1% NAA (FoshanYinghui Crop Science Co., Ltd., Foshan, China), on R. glutinosa yield was reported [ 16 ].…”