LaPT2 Gene Encodes a Flavonoid Prenyltransferase in White Lupin

Abstract

Legume plants are rich in prenylated flavonoid compounds, which play an important role in plant defense and human health. In the present study, we identified a prenyltransferase (PT) gene, named LaPT2, in white lupin (Lupinus albus), which shows a high identity and close relationship with the other known PT genes involved in flavonoid prenylation in planta. The recombinant LaPT2 protein expressed in yeast cells exhibited a relatively strong activity toward several flavonols (e.g., kaempferol, quercetin, and myricetin) and a relatively weak activity toward flavanone (naringenin). In addition, the recombinant LaPT2 protein was also active toward several other types of flavonoids, including galangin, morin, 5-deoxyquercetin, 4'-O-methylkaempferol, taxifolin, and aromadendrin, with distinct enzymatic affinities. The LaPT2 gene was preferentially expressed in the roots, which is consistent with the presence of prenylated flavonoid kaempferol in the roots. Moreover, we found that the expression level of LaPT2 paralleled with those of LaF3H1 and LaFLS2 genes that were relatively higher in roots and lower in leaves, suggesting that they were essential for the accumulation of prenylated flavonoid kaempferol in roots. The deduced full-length LaPT2 protein and its signal peptide fused with a green fluorescent protein (GFP) are targeted to plastids in the Arabidopsis thaliana protoplast. Our study demonstrated that LaPT2 from white lupin is responsible for the biosynthesis of prenylated flavonoids, in particular flavonols, which could be utilized as phytoalexin for plant defense and bioactive flavonoid compounds for human health.

The discovery of a key prenyltransferase gene assisted by a chromosome-level Epimedium pubescens genome

“…To examine the products in the EpPT8 catalyzed reaction using kaempferol as substrate, their HPLC chromatographs, MS spectra and MS/MS spectra were acquired for the confirmation of chemical property. The above reaction products were shown at about 55% conversion ratio of substrate to product and possessed the same HPLC retention time and reference data as 8-prenylkaempferol standard ( Figure 4D , Figure S3 , S4 ) ( Liu et al., 2021b ), indicating that EpPT8 was able to prenylate kaempferol at C-8 position. To confirm the chemical structure, the EpPT8 catalyzed reaction products were further separated with preparative liquid chromatograph and determined by NMR experiments.…”

“…Recent study showed that the recombinant LaPT2 protein from Lupinus albus (Leguminosae) could also use kaempferol as substrate to produce 8-prenylkaempferol, and possessed activity towards a wide range of flavonoid substrates, including flavonols, flavones, and naringenin, but L. albus plants only accumulate a trace amount of 8-prenylkaempferol in roots ( Liu et al., 2021b ). In a more recent study, the recombinant EsPT2 protein from E. sagittatum was found to be able to prenylate both kaempferol and methylated kaempferol ( Wang et al., 2021 ).…”

Heterologous biosynthesis of isobavachalcone in tobacco based on in planta screening of prenyltransferases

“…2b; Table 1). Such in vivo and in vitro difference seems to be not occasional in prenyltransferase studies, since the functions of SfN8DT (Sasaki et al 2008) and LaPT2 (Liu et al 2021) were reported to be different between transgenic Arabidopsis thaliana and recombinant proteins. This phenomenon is probably caused by different microenvironments in vitro and in planta, including substrate concentration and accessibility, subcellular localization of enzymes, co-factors, competitive inhibition of enzyme activity, etc.…”

Heterologous biosynthesis of isobavachalcone in tobacco based on in planta screening of prenyltransferases

“…However, when GuILDT was expressed with isoliquiritigenin in tobacco in our study, no IBC accumulation was observed ( Figure 2B ; Table 1 ). Such in vivo and in vitro difference seems to be not occasional in prenyltransferase studies, since the functions of SfN8DT ( Sasaki et al., 2008 ) and LaPT2 ( Liu et al., 2021 ) were reported to be different between transgenic Arabidopsis thaliana and recombinant proteins. This phenomenon is probably caused by different microenvironments in vitro and in planta , including substrate concentration and accessibility, subcellular localization of enzymes, co-factors, competitive inhibition of enzyme activity, etc.…”