Björn R Hamberger

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4-Coumarate:CoA ligase (4CL; EC has a pivotal role in the biosynthesis of plant secondary compounds at the divergence point from general phenylpropanoid metabolism to several major branch pathways. In Arabidopsis thaliana, we have identified a previously undetected, fourth and final member of the At4CL gene family. The encoded enzyme, At4CL4,(More)
Abstract Ecotilling was used as a simple nucleotide polymorphism (SNP) discovery tool to examine DNA variation in natural populations of the western black cottonwood, Populus trichocarpa, and was found to be more efficient than sequencing for large-scale studies of genetic variation in this tree. A publicly available, live reference collection of P.(More)
Diterpene resin acids (DRAs) are specialized (secondary) metabolites of the oleoresin defense of conifers produced by diterpene synthases and cytochrome P450s of the CYP720B family. The evolution of DRA metabolism shares common origins with the biosynthesis of ent-kaurenoic acid, which is highly conserved in general (primary) metabolism of gibberellin(More)
The plant enzyme 4-coumarate:coenzyme A ligase (4CL) is part of a family of adenylate-forming enzymes present in all organisms. Analysis of genome sequences shows the presence of '4CL-like' enzymes in plants and other organisms, but their evolutionary relationships and functions remain largely unknown. 4CL and 4CL-like genes were identified by BLAST(More)
Lignin is an important biopolymer that is deposited in secondary cell walls of plant cells (e.g., tracheary elements) and in response to stresses such as wounding. Biosynthesis of lignin monomers occurs via the phenylpropanoid pathway, in which the enzyme 4-coumarate:CoA ligase (4CL) plays a key role by catalyzing the formation of hydroxycinnamoyl-CoA(More)
Plants produce over 10,000 different diterpenes of specialized (secondary) metabolism, and fewer diterpenes of general (primary) metabolism. Specialized diterpenes may have functions in ecological interactions of plants with other organisms and also benefit humanity as pharmaceuticals, fragrances, resins, and other industrial bioproducts. Examples of(More)
The irreversible nature of reactions catalysed by P450s makes these enzymes landmarks in the evolution of plant metabolic pathways. Founding members of P450 families are often associated with general (i.e. primary) metabolic pathways, restricted to single copy or very few representatives, indicative of purifying selection. Recruitment of those and(More)
Forskolin, a complex labdane diterpenoid found in the root of Coleus forskohlii (Lamiaceae), has received attention for its broad range of pharmacological activities, yet the biosynthesis has not been elucidated. We detected forskolin in the root cork of C. forskohlii in a specialized cell type containing characteristic structures with histochemical(More)
Laser microdissection (LMD) has been established for isolation of individual tissue types from herbaceous plants. However, there are few reports of cell- and tissue-specific analysis in woody perennials. While microdissected tissues are commonly analyzed for gene expression, reports of protein, enzyme activity and metabolite analysis are limited due in part(More)
Three independent cytochrome P450 enzyme families catalyze the three rate-limiting hydroxylation steps in the phenylpropanoid pathway leading to the biosynthesis of lignin and numerous other phenolic compounds in plants. Their characterization at the molecular and enzymatic level has revealed an unexpected complexity of phenolic metabolism as the major(More)