Summary Objective Pathogenic variants in SCN1A can give rise to extremely variable disease severities that may be indistinguishable at their first presentation. We aim to find clinical features that can help predict the evolution of seizures into Dravet syndrome and clinical features that predict cognitive outcome in Dravet syndrome. We specifically investigate the role of contraindicated medication (CIM) as a possible modifier of cognitive decline. Methods A cohort of 164 Dutch participants with SCN1A‐related seizures was evaluated. Clinical data were collected from medical records and semistructured telephone interviews. Cognitive function was classified by a child neurologist, neuropsychologist, and clinical geneticist. Several clinical variables, including duration of CIM use in the first 5 years of disease, were evaluated in univariate and multivariate analyses. Results A longer duration of CIM use in the first 5 years after seizure onset was significantly associated with a worse cognitive outcome at time of inclusion, and with lower interpolated intelligence quotient/developmental quotient scores after the first 5 years of disease in Dravet syndrome patients. CIM use remained a significant predictor for cognitive outcome in a multivariate regression model, as did age at the first observation of developmental delay and age at first afebrile seizure. Age at first afebrile seizure was the most accurate predictor for evolution of seizures into Dravet syndrome for the complete cohort. Significance Our data suggest that a longer CIM use in the first 5 years of disease can have negative effects on cognitive outcome in Dravet syndrome. An early diagnosis is essential to avoid these drugs. Furthermore, we identified age at first afebrile seizure as an important predictor for evolution of seizures into Dravet syndrome and for the severity of Dravet syndrome, which can be used to counsel parents of young patients with SCN1A‐related seizures.

Glandular trichomes are specialized anatomical structures that accumulate secretions with important biological roles in plantenvironment interactions. These secretions also have commercial uses in the flavor, fragrance, and pharmaceutical industries. The capitate-stalked glandular trichomes of Cannabis sativa (cannabis), situated on the surfaces of the bracts of the female flowers, are the primary site for the biosynthesis and storage of resins rich in cannabinoids and terpenoids. In this study, we profiled nine commercial cannabis strains with purportedly different attributes, such as taste, color, smell, and genetic origin. Glandular trichomes were isolated from each of these strains, and cell type-specific transcriptome data sets were acquired. Cannabinoids and terpenoids were quantified in flower buds. Statistical analyses indicated that these data sets enable the high-resolution differentiation of strains by providing complementary information. Integrative analyses revealed a coexpression network of genes involved in the biosynthesis of both cannabinoids and terpenoids from imported precursors. Terpene synthase genes involved in the biosynthesis of the major monoterpenes and sesquiterpenes routinely assayed by cannabis testing laboratories were identified and functionally evaluated. In addition to cloning variants of previously characterized genes, specifically CsTPS14CT [(2)-limonene synthase] and CsTPS15CT (b-myrcene synthase), we functionally evaluated genes that encode enzymes with activities not previously described in cannabis, namely CsTPS18VF and CsTPS19BL (nerolidol/linalool synthases), CsTPS16CC (germacrene B synthase), and CsTPS20CT (hedycaryol synthase). This study lays the groundwork for developing a better understanding of the complex chemistry and biochemistry underlying resin accumulation across commercial cannabis strains.

Peppermint (Mentha × piperita L.) was transformed with various gene constructs to evaluate the utility of metabolic engineering for improving essential oil yield and composition. Oil yield increases were achieved by overexpressing genes involved in the supply of precursors through the 2C-methyl-D-erythritol 4-phosphate (MEP) pathway. Two-gene combinations to enhance both oil yield and composition in a single transgenic line were assessed as well. The most promising results were obtained by transforming plants expressing an antisense version of (+)-menthofuran synthase, which is critical for adjusting the levels of specific undesirable oil constituents, with a construct for the overexpression of the MEP pathway gene 1-deoxy-D-xylulose 5-phosphate reductoisomerase (up to 61% oil yield increase over wild-type controls with low levels of the undesirable side-product (+)-menthofuran and its intermediate (+)-pulegone). Elite transgenic lines were advanced to multiyear field trials, which demonstrated consistent oil yield increases of up to 78% over wild-type controls and desirable effects on oil composition under commercial growth conditions. The transgenic expression of a gene encoding (+)-limonene synthase was used to accumulate elevated levels of (+)-limonene, which allows oil derived from transgenic plants to be recognized during the processing of commercial formulations containing peppermint oil. Our study illustrates the utility of metabolic engineering for the sustainable agricultural production of high quality essential oils at a competitive cost.

The genus Mentha encompasses mint species cultivated for their essential oils, which are formulated into a vast array of consumer products. Desirable oil characteristics and resistance to the fungal disease Verticillium wilt are top priorities for the mint industry. However, cultivated mints have complex polyploid genomes and are sterile. Breeding efforts, therefore, require the development of genomic resources for fertile mint species. Here, we present draft de novo genome and plastome assemblies for a wilt-resistant South African accession of Mentha longifolia (L.) Huds., a diploid species ancestral to cultivated peppermint and spearmint. The 353 Mb genome contains 35 597 predicted protein-coding genes, including 292 disease resistance gene homologs, and nine genes determining essential oil characteristics. A genetic linkage map ordered 1397 genome scaffolds on 12 pseudochromosomes. More than two million simple sequence repeats were identified, which will facilitate molecular marker development. The M. longifolia genome is a valuable resource for both metabolic engineering and molecular breeding. This is exemplified by employing the genome sequence to clone and functionally characterize the promoters in a peppermint cultivar, and demonstrating the utility of a glandular trichome-specific promoter to increase expression of a biosynthetic gene, thereby modulating essential oil composition.