Tomato (Solanum lycopersicum) is a major crop plant and a model system for fruit development. Solanum is one of the largest angiosperm genera1 and includes annual and perennial plants from diverse habitats. Here we present a high-quality genome sequence of domesticated tomato, a draft sequence of its closest wild relative, Solanum pimpinellifolium2, and compare them to each other and to the potato genome (Solanum tuberosum). The two tomato genomes show only 0.6% nucleotide divergence and signs of recent admixture, but show more than 8% divergence from potato, with nine large and several smaller inversions. In contrast to Arabidopsis, but similar to soybean, tomato and potato small RNAs map predominantly to gene-rich chromosomal regions, including gene promoters. The Solanum lineage has experienced two consecutive genome triplications: one that is ancient and shared with rosids, and a more recent one. These triplications set the stage for the neofunctionalization of genes controlling fruit characteristics, such as colour and fleshiness.

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The tomato genome sequence provides insights into fleshy fruit evolution

Chemistry and biology of monoterpene indole alkaloid biosynthesis

Vascular plants appeared ~410 million years ago, then diverged into several lineages of which only two survive: the euphyllophytes (ferns and seed plants) and the lycophytes. We report here the genome sequence of the lycophyte Selaginella moellendorffii (Selaginella), the first nonseed vascular plant genome reported. By comparing gene content in evolutionarily diverse taxa, we found that the transition from a gametophyte- to a sporophyte-dominated life cycle required far fewer new genes than the transition from a nonseed vascular to a flowering plant, whereas secondary metabolic genes expanded extensively and in parallel in the lycophyte and angiosperm lineages. Selaginella differs in posttranscriptional gene regulation, including small RNA regulation of repetitive elements, an absence of the trans-acting small interfering RNA pathway, and extensive RNA editing of organellar genes.

https://science.sciencemag.org/content/sci/332/6032/960.full.pdf

The Selaginella genome identifies genetic changes associated with the evolution of vascular plants.

Alkaloids represent a highly diverse group of compounds that are related only by the occurrence of a nitrogen atom in a heterocyclic ring. Plants are estimated to produce approximately 12,000 different alkaloids, which can be organized into groups according to their carbon skeletal structures. Alkaloid biosynthesis in plants involves many catalytic steps, catalyzed by enzymes that belong to a wide range of protein families. The characterization of novel alkaloid biosynthetic enzymes in terms of structural biochemistry, molecular and cell biology, and biotechnological applications has been the focus of research over the past several years. The application of genomics to the alkaloid field has accelerated the discovery of cDNAs encoding previously elusive biosynthetic enzymes. Other technologies, such as large-scale gene expression analyses and metabolic engineering approaches with transgenic plants, have provided new insights into the regulatory architecture of alkaloid metabolism.

Alkaloid Biosynthesis: Metabolism and Trafficking

The production of plant secondary metabolites by means of large-scale culture of plant cells in bioreactors is technically feasible. The economy of such a production is the major bottleneck. For some costly products it is feasible, but unfortunately some of the most interesting products are only in very small amounts or not all produced in plant cell cultures. Screening, selection and medium optimization may lead to 20- to 30-fold increase in case one has producing cultures. In case of phytoalexins, elicitation will lead to high production. But for many of the compounds of interest the production is not inducible by elicitors. The culture of differentiated cells, such as (hairy) root or shoot cultures, is an alternative, but is hampered by problems in scaling up of such cultures. Metabolic engineering offers new perspectives for improving the production of compounds of interest. This approach can be used to improve production in the cell culture, in the plant itself or even production in other plant species or organisms. Studies on the production of terpenoid indole alkaloids have shown that the overexpression of single genes of the pathway may lead for some enzymes to an increased production of the direct product, but not necessarily to an increased alkaloid production. On the other hand feeding of such transgenic cultures with early precursors showed an enormous capacity for producing alkaloids, which is not utilized without feeding precursors. Overexpression of regulatory genes results in the upregulation of a series of enzymes in the alkaloid pathway, but not to an improved flux through the pathway, but feeding loganin does result in increased alkaloid production if compared with wild-type cells. Indole alkaloids could be produced in hairy root cultures of Weigelia by overexpression of tryptophan decarboxylase and strictosidine synthase. Alkaloids could be produced in transgenic yeast overexpressing strictosidine synthase and strictosidine glucosidase growing on medium made out the juice of Symphoricarpus albus berries to which tryptamine is added. Metabolic engineering thus seems a promising approach to improve the production of a cell factory.

Biotechnology for the production of plant secondary metabolites

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1016/S0014-5793(01)03045-9

Geraniol 10-hydroxylase1, a cytochrome P450 enzyme involved in terpenoid indole alkaloid biosynthesis

The complete 1H- and 13C-NMR assignments of the major Cannabis constituents, delta9-tetrahydrocannabinol, tetrahydrocannabinolic acid, delta8-tetrahydrocannabinol, cannabigerol, cannabinol, cannabidiol, cannabidiolic acid, cannflavin A and cannflavin B have been determined on the basis of one- and two-dimensional NMR spectra including 1H- and 13C-NMR, 1H-1H-COSY, HMQC and HMBC The substitution of carboxylic acid on the cannabinoid nucleus (as in tetrahydrocannabinolic acid and cannabidiolic acid) has a large effect on the chemical shift of H-1" of the C5 side chain and 2'-OH It was also observed that carboxylic acid substitution reduces intermolecular hydrogen bonding resulting in a sharpening of the H-5' signal in cannabinolic acid in deuterated chloroform The additional aromaticity of cannabinol causes the two angular methyl groups (H-8 and H-9) to show identical 1H-NMR shifts, which indicates that the two aromatic rings are in one plane in contrast to the other cannabinoids For the cannabiflavonoids, the unambiguous assignments of C-3' and C-4' of cannflavin A and B were determined by HMBC spectra

NMR assignments of the major cannabinoids and cannabiflavonoids isolated from flowers of Cannabis sativa.

A simple method is presented for the preparative isolation of seven major cannabinoids from Cannabis sativa plant material. Separation was performed by centrifugal partition chromatography (CPC), a technique that permits large‐scale preparative isolations. Using only two different solvent systems, it was possible to obtain pure samples of the cannabinoids; (−)‐Δ9‐(trans)‐tetrahydrocannabinol (Δ9‐THC), cannabidiol (CBD), cannabinol (CBN), cannabigerol (CBG), (−)‐Δ9‐(trans)‐tetrahydrocannabinolic acid‐A (THCA), cannabigerolic acid (CBGA), and cannabidiolic acid (CBDA). A drug‐type and a fiber‐type cannabis cultivar were used for the isolation. All isolates were shown to be more than 90% pure by gas chromatography. This method makes acidic cannabinoids available on a large scale for biological testing. The method described in this report can also be used to isolate additional cannabinoids from cannabis plant material.

Preparative isolation of cannabinoids from Cannabis sativa by centrifugal partition chromatography

The determination of ginkgolic acids in Ginkgo products is one of the principal components of quality control. However, a number of ginkgolic acids with different side chains may be present and this makes their analysis by conventional chromatographic methods more complex. In this study, 1H-NMR spectrometry was applied to the analysis of the total content of ginkgolic acids in leaves of Ginkgo biloba and in six types of commercial Ginkgo products in the absence of chromatographic purification. For this analysis, protons H-3, H-4, and H-5, which are well separated in the range 8 (ppm) 6.5-7.5 in the 1H-NMR spectrum, were utilised. For further confirmation, the correlations of H-3, H-4 and H-5 were examined by 1H-1H COSY spectra in all extracts. The quantity of the compounds was calculated from the relative ratio of the integral of each peak to the integral of the peaks of a known amount (100 microg) of anthracene used as an internal standard. The quantitative results obtained by 1H-NMR analysis were compared with those obtained by GC, which showed that the 1H-NMR method allows a simple quantification of total ginkgolic acids in Ginkgo extracts without any pre-purification steps.

Anja M.G. Peltenburg-Looman

Papers

Geraniol 10-hydroxylase1, a cytochrome P450 enzyme involved in terpenoid indole alkaloid biosynthesis

NMR assignments of the major cannabinoids and cannabiflavonoids isolated from flowers of Cannabis sativa.

Preparative isolation of cannabinoids from Cannabis sativa by centrifugal partition chromatography

Quantitative analysis of ginkgolic acids from Ginkgo leaves and products using 1H-NMR

Olivetol as product of a polyketide synthase in Cannabis sativa L