How to make bioactive alkaloids: Vinblastine and vincristine are important, expensive anticancer agents that are produced by dimerization of the plant-derived alkaloids catharanthine and vindoline. The enzymes that transform tabersonine into vindoline are known; however, the mechanism by which the scaffolds of catharanthine and tabersonine are generated has been a mystery. Caputi et al. now describe the biosynthetic genes and corresponding enzymes responsible. This resolves a long-standing question of how plant alkaloid scaffolds are synthesized, which is important not only for vinblastine and vincristine biosynthesis, but also for understanding the many other biologically active alkaloids found throughout nature. Science , this issue p. 1235

Summary: For almost a decade, our knowledge on the organisation of the family 1 UDP‐glycosyltransferases (UGTs) has been limited to the model plant A. thaliana. The availability of other plant genomes represents an opportunity to obtain a broader view of the family in terms of evolution and organisation. Family 1 UGTs are known to glycosylate several classes of plant secondary metabolites. A phylogeny reconstruction study was performed to get an insight into the evolution of this multigene family during the adaptation of plants to life on land. The organisation of the UGTs in the different organisms was also investigated. More than 1500 putative UGTs were identified in 12 fully sequenced and assembled plant genomes based on the highly conserved PSPG motif. Analyses by maximum likelihood (ML) method were performed to reconstruct the phylogenetic relationships existing between the sequences. The results of this study clearly show that the UGT family expanded during the transition from algae to vascular plants and that in higher plants the clustering of UGTs into phylogenetic groups appears to be conserved, although gene loss and gene gain events seem to have occurred in certain lineages. Interestingly, two new phylogenetic groups, named O and P, that are not present in A. thaliana were discovered.

Advances in omics technologies now permit the generation of highly contiguous genome assemblies, detection of transcripts and metabolites at the level of single cells and high-resolution determination of gene regulatory features. Here, using a complementary, multi-omics approach, we interrogated the monoterpene indole alkaloid (MIA) biosynthetic pathway in Catharanthus roseus, a source of leading anticancer drugs. We identified clusters of genes involved in MIA biosynthesis on the eight C. roseus chromosomes and extensive gene duplication of MIA pathway genes. Clustering was not limited to the linear genome, and through chromatin interaction data, MIA pathway genes were present within the same topologically associated domain, permitting the identification of a secologanin transporter. Single-cell RNA-sequencing revealed sequential cell-type-specific partitioning of the leaf MIA biosynthetic pathway that, when coupled with a single-cell metabolomics approach, permitted the identification of a reductase that yields the bis-indole alkaloid anhydrovinblastine. We also revealed cell-type-specific expression in the root MIA pathway.

Terpenoids represent the oldest known biomolecules, having been recovered from sediments as old as 2.5 billion years. Among plant secondary metabolites, they are the most abundant and diverse class of natural compounds. The diversity of terpenoids is probably a reflection of their many biological activities in nature, which has made them a widely used resource for traditional and modern human exploitation. They are usually the main constituents of essential oils of most plants offering a wide variety of pleasant scents from flowery to fruity, to woody or balsamic notes. For this reason terpenoids constitute a very important class of compounds for flavour and fragrance industries, in fact, in the US alone, the demand is forecast to grow 3.7 percent per year to $5.3 billion in 2012. The recent patents on production and extraction of terpenoids commonly used as natural flavouring compounds in food industries are reviewed in the present manuscript.

Plants produce an enormous array of biologically active metabolites, often with stereochemical variations on the same molecular scaffold. These changes in stereochemistry dramatically impact biological activity. Notably, the stereoisomers of the heteroyohimbine alkaloids show diverse pharmacological activities. We reported a medium chain dehydrogenase/reductase (MDR) from Catharanthus roseus that catalyses formation of a heteroyohimbine isomer. Here we report the discovery of additional heteroyohimbine synthases (HYSs), one of which produces a mixture of diastereomers. The crystal structures for three HYSs have been solved, providing insight into the mechanism of reactivity and stereoselectivity, with mutation of one loop transforming product specificity. Localization and gene silencing experiments provide a basis for understanding the function of these enzymes in vivo. This work sets the stage to explore how MDRs evolved to generate structural and biological diversity in specialized plant metabolism and opens the possibility for metabolic engineering of new compounds based on this scaffold.