4-Hydroxycinnamoyl-CoA hydratase/lyase, an enzyme of phenylpropanoid cleavage from Pseudomonas , causes formation of C 6 -C 1 acid and alcohol glucose conjugates when expressed in hairy roots of Datura stramonium L.

Abstract

4-Hydroxycinnamoyl-CoA hydratase/lyase (HCHL), a crotonase homologue of phenylpropanoid catabolism from Pseudomonas fluorescens strain AN103, led to the formation of 4-hydroxybenzaldehyde metabolites when expressed in hairy root cultures of Datura stramonium L. established by transformation with Agrobacterium rhizogenes. The principal new compounds observed were the glucoside and glucose ester of 4-hydroxybenzoic acid, together with 4-hydroxybenzyl alcohol- O-beta- D-glucoside. In lines actively expressing HCHL, these together amounted to around 0.5% of tissue fresh mass. No protocatechuic derivatives were found, although a trace of vanillic acid-beta- D-glucoside was detected. There was no accumulation of 4-hydroxybenzaldehydes, whether free or in the form of their glucose conjugates. There was some evidence suggesting a diminished availability of feruloyl-CoA for the production of feruloyl putrescine and coniferyl alcohol. The findings are discussed in the context of a diversion of phenylpropanoid metabolism, and the ability of plants and plant cultures to conjugate phenolic compounds.

Simultaneous quantification of phenolic acids and flavonoids in Chamaerops humilis L. using LC–ESI-MS/MS

“…The other reflux extracts contained lower concentrations of that molecule. This aldehyde, contributes to the original natural flavour of vanilla and is a very popular flavouring agent used in large range of foods and as fragrance ingredients (Mitra et al, 2002).…”

Vanillin production in metabolically engineered Beta vulgaris hairy roots through heterologous expression of Pseudomonas fluorescens HCHL gene

“…Recombinant strains of E.coli and other bacteria were also developed by inserting the EhyAB, CalA, and CalB gene for vanillin production, which catalysed the same reaction as that of the HCHL gene (Kaur and Chakraborty, 2013). On the other hand, insertion and expression of this HCHL gene in Datura stramonium hairy roots resulted in the accumulation of glucoside/glucose ester of 4-hydroxybenzoic acid and trace amount of vanillic acid with no vanillin production, which has been interpreted to might have occurred due to lesser availability of feruloyl CoA as its substrate (Mitra et al, 2002). Similarly, on introduction of this gene in Beta vulgaris resulted into the production of p-hydroxy benzaldehyde as the end product and no trace of vanillin was noted (Rahman et al, 2009).…”

<i>Azospirillum</i> Growth Promotion Is Related to Changes in Ferulate and Dehydrodiferulate Contents in Cell Wall of Inoculated Cucumber Seedlings Hypocotyls

“…Enzyme extraction steps were carried out at 4˚C. One g FW of each pooled segment tissue was crushed in liquid nitrogen in presence of 1% (w/w) polyvinyl pyrrolidone, and then extracted with 4 ml of 100 mM Tris-HCl buffer (pH 8.5) supplemented with 10 mM EDTA, and 0.08 mM β-mercaptoetanol [36]. The suspension was homogenized for 1 min and then centrifuged at 2830 × g for 20 min at 4˚C.…”

“…The suspension was homogenized for 1 min and then centrifuged at 2830 × g for 20 min at 4˚C. PAL was assayed directly in the supernatant [36] after passing it through a 0.45 µm membrane (Millipore, Bedford, USA). 100 mM Tris-HCl (pH 8.5) was used as assay buffer.…”