N. glutinosa L. is a relatively less studied Nicotiana species (Solanaceae), although there are data about its importance as a model plant in viral control studies, as a gene donor in tobacco hybridization and as a source of agents with insecticidal or fungicidal effects. The biological activities of the species were associated mostly with the presence of leaf surface metabolites, in particular diterpenes and sucrose esters. The aim of this study was to identify the chemical composition of the essential oil (EO) and two aromatic extraction products (concrete and resinoid) obtained from N. glutinosa L. leaves. GC-MS analysis identified 26 components in the EO (representing 97.3% of total oil content), which contained mostly diterpene compounds with major components manool (14.2%), sclarene (8.4%) and manoyl oxide (8.1%). The number of compounds identified in the concrete was 37 (95.5% of the total content) and the major component was the diterpene alcohol sclareol (14.2%). In the resinoid, 30 volatile components (representing 95.1% of resinoid content) were identified, with major components nicotine (32.9%), α-tocopherol (8.2%), tridecanoin (6.9%), sclareol (6.9%), and solanone (6.9%). The group of bicyclic diterpenes had the largest share in the diterpene fraction of the products (57.3%, 91.7%, and 86.3%, respectively for the EO, concrete, and resinoid). Considering the abundance of sclareol in the aromatic products, the antimicrobial activity of the pure substance was determined. Sclareol was highly effective against a set of medicinally important yeasts; Candida albicans AТCC 10231, C. glabrata ATCC 90030, C. parapsilosis clinical isolate, and C. tropicalis NBIMCC 23, while being less effective against the studied Gram-positive and Gram-negative bacteria. Data from the study on N. glutinosa aromatic products composition may be of interest to the aroma industries for their possible use in perfumery and cosmetics.Molecules 2020, 25, 30 2 of 16 N. glutinosa is native to Northern and Central Peru and Southern Ecuador, where it has adapted well to semi-arid areas, rocky slopes and ditch banks [1,5]. Plants are more fragile and with tender stem than common tobacco (N. tabacum), rarely branching [6]. Leaves are petiolate, heart-shaped; with a maximum length of about 23 cm. Inflorescences are racemose with long peduncles. Unlike N. tabacum, the flowers of N. glutinosa tend to form bilabiate corolla and are deep orange in color with long anthers adhering to the upper lobe of the corolla, as in the bilabiate flowers of other families [6]. N. glutinosa germinates readily and grows well in both a greenhouse and the field [7]. There are three accessions of N. glutinosa, labeled as accessions (acc.) 24, 24A, and 24B [8].Data on the chemical composition of N. glutinosa leaves are generally limited [5], with the exception of those for alkaloids, as well as for sucrose esters, diterpene alcohols and other leaf surface exudate components [8][9][10][11][12][13][14][15]. The major alkaloid in N. glutinosa is nornicotine [16], alth...

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Belowground interactions of plants with other organisms in the rhizosphere rely on extensive small-molecule communication. Chemical signals released from host plant roots ensure the development of beneficial arbuscular mycorrhizal (AM) fungi which in turn modulate host plant growth and stress tolerance. However, parasitic plants have adopted the capacity to sense the same signaling molecules and to trigger their own seed germination in the immediate vicinity of host roots. The contribution of AM fungi and parasitic plants to the regulation of phytohormone levels in host plant roots and root exudates remains largely obscure. Here, we studied the hormonome in the model system comprising tobacco as a host plant, Phelipanche spp. as a holoparasitic plant, and the AM fungus Rhizophagus irregularis. Co-cultivation of tobacco with broomrape and AM fungi alone or in combination led to characteristic changes in the levels of endogenous and exuded abscisic acid, indole-3-acetic acid, cytokinins, salicylic acid, and orobanchol-type strigolactones. The hormonal content in exudates of broomrape-infested mycorrhizal roots resembled that in exudates of infested non-mycorrhizal roots and differed from that observed in exudates of non-infested mycorrhizal roots. Moreover, we observed a significant reduction in AM colonization of infested tobacco plants, pointing to a dominant role of the holoparasite within the tripartite system.

The genus Nicotiana (Solanaceae) includes over 70 species, with a long history of traditional use; many of them are nowadays used in bioengineering, biosynthesis, molecular biology, and other studies, while common tobacco, N. tabacum L., is one of the most economically important industrial crops worldwide. Although Nicotiana species have been extensively investigated, relatively less research has focused on flowers, especially research related to obtaining aromatic products for cosmetic and perfumery use. On the other hand, there is evidence that Nicotiana flowers accumulate various secondary metabolites with a distinct aroma and biological activities, and the flowers represent a biomass available in sufficient quantities. Therefore, this study aimed to determinate the chemical composition (by GC-MS) and the olfactory profiles of a specific type of natural aromatic product (concrete), obtained from the flowers of four Nicotiana species, in a direct comparison between them. The yields of extracted concrete were sufficiently high, varying between the species, 1.4% (N. rustica L.), 2.5% (N. glutinosa L.), 1.6% (N. alata Link&Otto genotype with white flowers), 2.7% (N. alata genotype with pink flowers), 3.2% (N. tabacum, Oriental type), and 5.2% (N. tabacum, Virginia type). The major components of the obtained concretes belonged to different chemical classes: N. rustica and N. tabacum (OR), the hydrocarbons n-tetratriacontane (14.5%; 15.0%) and n-triacontane (12.1%; 13.3%), and 3-methyl-pentanoic acid (11.1%; 12.2%); N. glutinosa, the diterpenes sclareol (25.9%), 3-α-hydroxy-manool (16.3%), and 13-epimanool (14.9%); N. alata (WF), the phenylpropanoid terephthalic acid and di(2-ethylhexyl) ester (42.9%); N. alata (PF), the diterpene tributyl acetylcitrate (30.7%); and N. tabacum (FCV), the hydrocarbons n-hexacosane (12.9%) and n-pentacosane (12.9%). Each of the flower concretes revealed a characteristic odor profile. This is the first report about Nicotiana species as a source for obtaining flower concretes; these initial results about the concrete yield, olfactory profile, and chemical composition are a prerequisite for the possible processing of Nicotiana flowers into new aromatic products for use in perfumery and cosmetics. The study provides new data in favor of the potential of the four Nicotiana species as aromatic plants, as well as a possible alternative use of flowers, a valuable, but discarded, plant material in other applications.

Broomrapes are root holoparasites from Orobanchaceae family parasitizing other flowering plants. Several of the most aggressive broomrape species are widely spread in Bulgaria often causing serious yield losses of important crops. It is important to be able to detect the presence of broomrape seeds in the soil. In the present study, we combined a proven PCR-based assay for detection of broomrape seeds with methods to distinguish species based on nuclear ITS sequences to identify broomrape seeds isolated from soil samples and to study the population structure and the intraspecific variations within the three species. Fifty-six soil samples from 23 different regions in Bulgaria were studied. Based on molecular and bioinformatics analyses we found that 22 samples contained seeds of Orobanche cernua var. cumana and six samples, seeds of Phelipanche ramosa. Phylogenic and bioinformatics analyses surprisingly revealed that the isolated sequences from supposedly P. mutelii seeds diverge from those annotated in NCBI by other authors on 16 different nucleotide positions and formed two distant branches of the phylogenic tree. On the other hand, the isolated sequences were almost identical with P. rosmarina. Tajimas' D-test revealed that O. cumana populations are currently stable. Regarding the Phelipanche representatives, based on the D-test we can hypothesize that P. mutelii/P. rosmarina populations are in a period of active expansion, while P. ramosa populations are contracting. All isolated sequences were deposited in NCBI Genbank database. ARTICLE HISTORY