Biology subjects

Wurlitzer, J.

Publications and source records attributed to Wurlitzer, J..

6 recordsLinked to original sources

bioRxiv2025

Discovery of iridoid cyclase completes the iridoid pathway in asterids

Iridoids are specialized monoterpenes ancestral to asterid flowering plants (Albach et al, 2001; Stull et al, 2018). Iridoids play key roles in plant defense and are also essential precursors for pharmacologically important alkaloids (Dobler et al, 2011; Eisner, 1964). The biosynthesis of all iridoids involves the cyclization of a reactive enol intermediate. While this cyclization occurs spontaneously at low yields, it has long been hypothesized that a dedicated enzyme is involved in this process (Geu-Flores et al, 2012; Lichman et al, 2019b). Here, we report the discovery of asterid iridoid cyclases (ICYC). We show that these enzymes catalyze cyclization of the reactive intermediate to form the two major iridoid stereoisomers found in plants. Our work uncovers the last missing key step in the otherwise well-characterized iridoid biosynthesis pathway in asterids. This discovery unlocks the possibility to generate previously inaccessible iridoid stereoisomers, which will enable metabolic engineering for the sustainable production of valuable iridoid and iridoid-derived compounds.

plant biology↗

bioRxiv2025

Single-cell metabolome and RNA-seq multiplexing on single plant cells

Plants produce valuable natural products used for a wide variety of industrial applications. Since these molecules have important applications in a variety of industrial sectors, there is enormous interest in elucidating the biosynthetic pathways that are responsible for the production of these compounds. Identification of the genes that comprise these biosynthetic pathways has been enabled by gene-to-metabolite networks that are generated from transcriptomic and metabolomic datasets. Recent advances in both single-cell RNA-seq (scRNA-seq) and single-cell mass spectrometry metabolomics (scMS) have enabled the measurement of either gene expression or metabolite levels in individual cells. However, these individual datasets can only be used to indirectly correlate gene expression levels with metabolite concentrations at the single cell level. Here we demonstrate that both scRNA-seq and scMS can be applied to the same plant cell, thereby enabling direct comparisons between gene expression and metabolite levels. This multiplexing approach reveals both qualitative and quantitative correlations between metabolite levels and biosynthetic gene expression in individual cells. This integrated approach sheds light on the underlying processes driving complex plant biosynthesis.

plant biology↗

bioRxiv2025

BAHD news from Euphorbia peplus: identification of acyltransferase enzymes involved in ingenane diterpenoid biosynthesis

O_LIThe plant family Euphorbiaceae are an abundant source of structurally complex diterpenoids, many of which have reported anti-cancer, anti-HIV, and anti-inflammatory activities. Among these, ingenol-3-angelate (1a; tradename: Picato(R)), isolated from Euphorbia peplus, has potent anti-tumour activity. C_LIO_LIHere we report the discovery and characterization of the first genes linked to the committed steps of ingenol-3-angelate (1a) biosynthesis in Euphorbia peplus. We identified two genes, the products of which catalyse the addition of angelyl-CoA (9a) to the ingenol (5) scaffold to produce ingenol-3-angelate (1a). C_LIO_LIWe demonstrate using VIGS that just one of these genes, EpBAHD-08, is essential for this angeloylation in E. peplus. VIGS of the second gene, EpBAHD-06, has a significant effect on jatrophanes rather than ingenanes in E. peplus. C_LIO_LIWe also identified three genes whose products can catalyse acetylation of ingenol-3-angelate (1a) to ingenol-3-angelate-20-acetate (2). In this case VIGS indicates considerable functional redundancy in the E. peplus genome of genes encoding this enzymatic step. C_LIO_LIThis work paves the way for increasing ingenol-3-angelate (1a) levels in planta and provides a foundation for the discovery of the remaining genes in the biosynthetic pathway of these important molecules. C_LI

biochemistry↗

bioRxiv2024

Single-cell mass spectrometry reveals heterogeneous triterpenic acid accumulation in apple callus-derived cells

The use of plant cell cultures for large scale production of natural compounds, although promising, has been hindered by their genetic instability and heterogeneity. Here, we show how single cell mass spectrometry can be used to characterize the natural product profile of a callus culture at a highly resolved level. We identify and quantify triterpenic acids in a population of callus cells derived from Annurca apple (Malus pumila Miller cv Annurca) leaf. The analysis demonstrated that a high degree of metabolic heterogeneity exists in the cell population, with the levels of detected metabolites varying significantly across the callus cells. This metabolic heterogeneity was underpinned by variable expression levels of key biosynthetic genes in the single cells. The application of an abiotic stress, near ultraviolet radiation (NUV), to the callus culture resulted in increased levels of triterpenic acids. Single cell mass spectrometry analysis revealed that after treatment, a larger percentage of callus cells produced detectable amounts of these metabolites, ultimately resulting in a more homogeneous production of the metabolites. Furthermore, it showed that intracellular concentrations of ursolic acid derivatives can reach more than 100 mM. Single cell mass spectrometry analyses provide a starting foundation for understanding the molecular mechanisms responsible for metabolic heterogeneity in plant cell cultures, which could in turn facilitate efforts to improve these cell cultures for commercial purposes.

plant biology↗

bioRxiv2024

Independent evolution of ipecac alkaloid biosynthesis

Ipecac alkaloids are medicinal monoterpenoid-derived tetrahydroisoquinoline alkaloids found in two distantly related plants: Carapichea ipecacuanha (Gentianales) and Alangium salviifolium (Cornales). We have elucidated ipecac alkaloid biosynthesis in both species, conclusively demonstrating that biosynthesis of the structurally complex ipecac alkaloid protoemetine has evolved independently. We show that although protoemetine biosynthesis proceeds via the same chemical logic in both species, each plant uses a distinct monoterpene precursor. Moreover, we provide evidence that both plants initiate ipecac biosynthesis by a non-enzymatic Pictet-Spengler reaction, and we elucidate the biosynthetic fate of both the 1R and 1S stereoisomers that are produced in this non-stereoselective reaction. Phylogenetic analyses clearly show independent pathway evolution through parallel and convergently evolved enzymes. This work provides insight into how nature can capitalize on highly reactive starting substrates, the manner in which multi-step pathways can arise, and also lays the foundation for metabolic engineering of these important medicinal compounds.

plant biology↗

bioRxiv2024

Quantitative single cell mass spectrometry reveals the dynamics of plant natural product biosynthesis

Plants produce an extraordinary array of complex natural products (specialized metabolites). Since the biosynthetic genes that are responsible for synthesis of these molecules are often localized to rare or distinct cell types, recently developed single cell RNA-sequencing (scRNA-seq) approaches have tremendous potential to resolve these complex pathways. In contrast, detection, identification, and quantification of metabolites in single cells has remained challenging. Here, we report a robust method for single cell mass spectrometry in which we rigorously characterize and quantify the concentrations of four classes of natural products in individual cells of leaf, root, and petal of the medicinal plant Catharanthus roseus. These single cell mass spectrometry datasets reveal information about the biosynthetic processes that cannot be determined from the corresponding scRNA-seq data alone, providing a highly resolved picture of natural product biosynthesis at cell-specific resolution.

biochemistry↗