Effect of UV‐B radiation on growth, flavonoid and podophyllotoxin accumulation, and related gene expression in Sinopodophyllum hexandrum

Abstract

Sinopodophyllum hexandrum is an alpine medicinal plant that produces the anticancer compound podophyllotoxin (PPT). Although a positive relationship between PPT content and altitude has been proved and low temperature enhances plant growth and PPT accumulation has also been revealed, the role of UV radiation in regulating growth and PPT accumulation is still unclear • In this study, morphophysiological traits, metabolites content and related genes expression were investigated by exposing S. hexandrum seedlings to treatment with UV-B radiation.• The results showed that the contents of soluble sugars and flavonoids, and the expression levels of genes involved in glycometabolism (XET and b-1,3-glucanase) and flavonoid biosynthesis (PAL,C4H,4CL,CHS1 and DTX41) were enhanced in response to UV-B compared to CK. Moreover, genes involved in stress tolerance (MYB, WRKY,APX3 and EX2) were also upregulated in response to UV-B radiation. Although the whole plant biomass exhibited slightly increased values that depended largely on root development, the contents of chlorophyll and PPT and the expression levels of genes involved in photosynthesis (matK, ndhF,rbcL and ycf5) and PPT biosynthesis (C3H,CCoAMT,CCR,CAD, DPO, PLR,SDH, CPY719A23,OMT3,CYP71CU1,OMT1and 2-ODD) were significantly decreased in response to UV-B compared to CK.• It can be concluded that UV-B radiation promotes soluble sugars and flavonoids accumulation, but inhibits PPT biosynthesis in S. hexandrum.

Effects of Light on Secondary Metabolite Biosynthesis in Medicinal Plants

“…For example, supplemental UV-B radiation significantly improved the activities of phenylalanine ammonia-lyase (PAL), cinnamyl alcohol dehydrogenase (CAD), 4-coumaric acid: CoA ligase (4CL), CHI, and dihydroflavonol 4-reductase (DFR), and enhanced the contents of flavonoids and phenolicp0s in the leaves of C. forskohlii and Withania somnifera Agrawal, 2014, 2015). In Sinopodophyllum hexandrum, treatment with UV-B (1.07 W•m −2 ) significantly decreased the content of podophyllotoxin as well as transcript levels of 12 related genes, including cinnamic acid 3-hydroxylase (C3H), caffeoyl-CoA O-methyltransferase (CCoAMT), cinnamoyl-CoA reductase (CCR), CAD, dirigent protein oxidase (DPO), pinoresinol-lariciresinol reductase (PLR), secoisolariciresinol dehydrogenase (SDH), cytochrome P450 719A23 (CPY719A23), O-methyltransferase3 (OMT3), cytochrome P450 71CU1 (CYP71CU1), OMT1, and 2-oxoglutarate/Fe(II)-dependent dioxygenase (2-ODD; Lv et al, 2021). In Glycyrrhiza uralensis, Zhang et al (2018a) showed that UV-B radiation stimulated the expression of several genes involved in the flavonoid biosynthetic pathway, such as cinnamic acid 4-hydroxylase (C4H), PAL, CHS, CHI, and FLS.…”

Cool Temperature Enhances Growth, Ferulic Acid and Flavonoid Biosynthesis While Inhibiting Polysaccharide Biosynthesis in Angelica sinensis

“…Flavonoids content was determined using the NaNO 2 -AlCl 3 -NaOH method [ 43 , 44 ]. Briefly, the extracts (2.5 mL) were added into ddH 2 O (2 mL) and NaNO 2 (5% w / v , 0.3 mL); after oscillation, and AlCl 3 (10% w / v , 0.3 mL) was added and reacted at 22 °C for 1 min; then, NaOH (1.0 mol/L, 2 mL) was added to stop the reaction.…”

Integrated Metabolomic and Transcriptomic Analysis Reveals Differential Mechanism of Flavonoid Biosynthesis in Two Cultivars of Angelica sinensis

“…The extracts were increased to 20 mL with ethanol (95% v / v ). Total flavonoids content was measured according to a NaNO 2 -AlCl 3 -NaOH method [ 51 , 52 ]. Briefly, extracts (150 μL) were added in ddH 2 O (2 mL) and NaNO 2 (5% w / v , 0.3 mL).…”