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The presence of anticancer clerodane diterpenoids is a chemotaxonomic marker for the traditional Chinese medicinal plant Scutellaria barbata, although the molecular mechanisms behind clerodane biosynthesis are unknown. Here, we report a high-quality assembly of the 414.98 Mb genome of S. barbata into thirteen pseudochromosomes. Using phylogenomic and biochemical data, we mapped the plastidial metabolism of kaurene (gibberellins), abietane and clerodane diterpenes in three species of the family Lamiaceae (Scutellaria barbata, Scutellaria baicalensis and Salvia splendens), facilitating the identification of genes involved in the biosynthesis of the clerodanes, kolavenol and isokolavenol. We show that clerodane biosynthesis evolved through recruitment and neofunctionalization of genes from gibberellin and abietane metabolism. Despite the assumed monophyletic origin of clerodane biosynthesis which is widespread in species of the Lamiaceae, our data show distinct evolutionary lineages and suggest polyphyletic origins of clerodane biosynthesis in the family Lamiaceae. Our study not only provides significant insights into the evolution of clerodane biosynthetic pathways in the mint family, Lamiaceae, but also will facilitate the elucidation of anticancer clerodanes biosynthesis and future metabolic engineering efforts to increase the production of these high-value chemicals.

Cistus creticus subsp. creticus is a shrubby Mediterranean plant used since ancient times in folk medicine for the treatment of different diseases. C. creticus extracts and resin contain different types of secondary metabolites, such as terpenoids (predominantly labdane type diterpenoids), and phenylpropanoids. Growth conditions seem to influence the content of labdane-type diterpenes and flavan-3-ols in leaves of C. creticus subsp. creticus. Histochemical staining of leaves’ trichomes and comprehensive phytochemical characterization of resin, leaves and their exudates, indicated that long-stalked capitate trichomes of C. creticus subsp. creticus, grown both in vitro (IV) and in greenhouse (GH), are capable of producing bioactive oleoresin-related terpenoids and phenylpropanoids compounds. Bioactivity-guided approach was implemented in search for the major antibacterial compound in C. creticus resin against two Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and two Gram-positive bacteria (Bacillus cereus and Micrococcus flavus). Bioautographic assay on TLC plates with separated components of Cistus resin extract, revealed a pronounced zone of microbial growth inhibition, corresponded to a highly active compound with Rf values of 0.45, structurally characterized and identified as ent-3β-acetoxy-13-epi-manoyl oxide. This finding opens the route for focusing on isolation and functional characterization of genes involved in the biosynthesis of ent-3β-acetoxy-13-epi-manoyl oxide and its precursor ent-3β-hydroxy-13-epi-manoyl oxide, with the aim to establish sustainable in vitro biotechnological protocols for its large-scale production in homologous and heterologous plant and microbial hosts.

Rosmarinus officinalis L. belongs to the Lamiaceae family and is cultivated worldwide due to its diverse uses as an ornamental evergreen shrub in gardening, as well as a food seasoning and a natural medicine. The present research was conducted to study the morphological traits of seven wild-grown rosemary populations in Greece, as well as the propagation of two selected populations with the most desirable ornamental characteristics, by the use of shoot cuttings and in vitro cultures. From the study of the morphological traits of the seven populations, those with interesting features were grown in the areas of Amaliada and Piperia and, thus, were chosen for studying their propagation. Rooting of the shoot cuttings was carried out during the four seasons of the year, using potassium salt Indole-3-butyric acid (K-IBA) at concentrations of 0.5 and 1 g·L−1, in various substrates under the intermittent mist or fog system. It was found that the shoot cuttings rooted easily in all four seasons, but there were better results for the population of ‘Piperia’ in autumn, with 1 g·L−1 K-IBA (80%), and ‘Amaliada’ in spring, with 0.5 g·L−1 K-IBA (82.5%), while higher rooting percentages were achieved in the fog system, on a substrate consisting of perlite and peat, in a ratio of 2:1 (85%). For the in vitro cultures, shoot tips excised from the two selected populations were successfully disinfested by pre-soaking in an antioxidant solution and then, by sterilizing them in 0.6% (w/v) NaOCl, followed by transferring them onto a Murashige and Skoog (MS) nutrient medium. ‘Amaliada’ cultures proved to be the most productive population (2.1 shoots per explant), with the highest shoot formation frequency (91.6%), when cultivated on the MS nutrient medium without plant growth regulators. For ‘Piperia’ cultures, the highest shoot formation frequency (66.6%) was achieved on the MS nutrient medium supplemented with 0.25 or 0.5 mg·L−1 6-Benzyloaminopurine (BAP) and 0.1 mg·L−1 Indole-3-acetic acid (IAA). Spontaneous root formation frequency was noticed on the MS nutrient medium, containing 0.5 mg·L−1 BAP and 0.1 mg·L−1 IAA, for both ‘Amaliada’ and ‘Piperia’ cultures (50% and 41.6%, respectively) in a single stage, with root lengths of 7.1 and 5.3 cm, respectively. Rosemary plantlets, with roots formed in vitro after transplanting them in soilless substrate, were acclimatized adequately in the greenhouse environment (~70%).