Schimp., spreading earthmoss; Picea abies (L.) H. Karst; Norway spruce; Picea
Schimp., spreading earthmoss; Picea abies (L.) H. Karst; Norway spruce; Picea glauca (Moench) Voss; white spruce; Picea sitchensis (Bongard) Carri e; 1855; Sitka spruce; Pinus banksiana Lamb., jack pine; Pinus contorta Douglas; lodgepole pine; Pinus nigra J.F. Arnold; Austrian pine or black pine; Pinus nigra subsp. laricio (Poiret) Maire; Calabrian pine; Pinus PLD medchemexpress pinaster Aiton; maritime pine; Pinus radiata D. Don; Monterey pine; Pinus taeda L., loblolly pine; Pseudolarix amabilis (N. Nelson) Rehder; golden larch.Plants 2021, ten, 2391. doi/10.3390/ 2021, 10,2 of1. Introduction Gymnosperms developed many different physical and chemical defences against pathogens and herbivores, among which one in the most substantial is definitely the production of terpenoid metabolites [1]. The complex terpenoid defence mechanisms have persisted all through the extended evolutionary history of gymnosperms and their decreasing geographical distribution during the Cenozoic era [5,6], but diversified into usually species-specific metabolite blends. As an example, structurally related labdane-type diterpenoids, for example ferruginol and derivative compounds, act as defence metabolites in many Cupressaceae species [3,7,8]. However, diterpene resin acids (DRAs), collectively with mono- and sesqui-terpenes, would be the most important components of the oleoresin defence method in the Pinaceae species (e.g., conifers), and happen to be shown to provide an effective barrier against stem-boring weevils and connected pathogenic fungi [92]. Diterpenoids from gymnosperms are also crucial for their BMX Kinase supplier technological makes use of, being employed in the production of solvents, flavours, fragrances, pharmaceuticals as well as a huge choice of bioproducts [1,13], such as, among the a lot of other examples, the anticancer drugs pseudolaric acid B, obtained in the roots from the golden larch (Pseudolarix amabilis) [14], and taxol, extracted from yew (Taxus spp.) [15], also as cis-abienol, made by balsam fir (Abies balsamea), which can be a molecule of interest for the fragrance market [16]. The diterpenoids of conifer oleoresin are largely members of three structural groups: the abietanes, the pimaranes, and also the dehydroabietanes, all of which are characterized by tricyclic parent skeletons [2,17]. These diterpenoids are structurally similar to the tetracyclic ent-kaurane diterpenes, which involve the ubiquitous gibberellin (GA) phytohormones. Both the oleoresin diterpenoids of specialized metabolism and also the GAs of common metabolism derive from the common non-cyclic diterpenoid precursor geranylgeranyl diphosphate (GGPP). In conifers, among the other gymnosperms, the structural diversity of diterpenoids results from the combined actions of diterpene synthases (DTPSs) and cytochrome P450 monooxygenases (CP450s) [2]. The former enzymes catalyse the cyclization and rearrangement of the precursor molecule GGPP into a selection of diterpene olefins, often known as the neutral elements from the oleoresins. Olefins are then functionalized at specific positions by the action of CP450s, by means of a sequential three-step oxidation initial to the corresponding alcohols, then to aldehydes, and lastly to DRAs [2], for example abietic, dehydroabietic, isopimaric, levopimaric, neoabietic, palustric, pimaric, and sandaracopimaric acids, which are the significant constituents of conifer oleoresins [2,17,18]. The chemical structures of the most-represented diterpenoids in Pinus spp. are reported in Figure S1. Dite.