Composition, viscosity and solubility of saleps from twenty different orchid (Orchidaceae) species

Phytochemical Analysis of Anacamptis coriophora Plant Cultivated Using Ex Vitro Symbiotic Propagation

This study aims to investigate the functional groups and phytochemical profile of Anacamptis coriophora seeds, tubers, and flowers. Symbiotic seedlings produced using the ex vitro method were transferred to their natural habitat and grown to analyze the functional groups and phytochemical profiles of tubers and flowers. The life cycles of the transferred seedlings were monitored, and tubers and flowers were harvested for analysis. ATR-FTIR spectroscopy revealed the presence of functional groups such as polysaccharides, lignin, and proteins in both tubers and flowers. Differences in spectral frequencies between first-year and second-year tubers were observed. Fatty acid analysis identified 30 different compounds in seeds, flowers, and tubers, with linoleic acid being the most abundant (27 % in seeds, 33 % in tubers), and palmitic acid present in flowers (24 %). GC-MS analysis of ethanol extracts from these components highlighted the presence of 32 compounds, including hydroxyacetic acid, hydrazide, cytidine (Z)-7-hexadecenal, 2,2-dimethoxyethane, 2,5,6-trimethyldecane, and butanamide, 4-amino-N-hydroxy. A. coriophora's tubers, flowers, and seeds may contain active metabolites with therapeutic potential. These results are valuable for the commercial cultivation of the plant.

Large-Scale In Vitro Multiplication and Phytochemical Analysis of Himantoglossum affine (Boiss.) Schltr.: An Endangered Euro-Mediterranean Terrestrial Orchid

Himantoglossum affine is a threatened terrestrial orchid. We aimed to optimize asymbiotic seed germination and direct embryogenesis and to analyze the phytochemical profile and physico-biochemical analysis of leaf and tuber. The individual use of organic nitrogen compounds resulted in higher germination efficiencies, while the shortest times to germination were observed using coconut water plus casein hydrolysate. Plantlets grown on media supplemented with pineapple juice and peptone had the highest plantlet length and weight. For embryogenesis, the highest regeneration rate (44%) and embryo number/explant (10.12 ± 2.08) were observed in young protocorm-like body (PLB) explants with 0.5 mg/L naphthalene acetic acid (NAA) and 1 mg/L thidiazuron (TDZ). During the acclimatization process, the scattered vascular tubes converted to fully developed vascular tissues, ensuring maximum sap flux. Gas chromatography–mass spectrometry analysis identified 1,2,3-propanetriol, monoacetate, 4H-pyran-4-one, 2,3-dihydro-3,5-dihydroxy-6-methyl, and 2-butenedioic acid, 2-methyl-, (E)- as the most prevalent compounds. We reported higher contents of total phenolics and flavonoids and antioxidant activity compared to other terrestrial orchids. The glucomannan content (36.96%) was also higher than starch content (31.31%), comparable to those reported in other tuberous orchids. Based on the fragmentation of H. affine populations in the Middle East and Euro-Mediterranean countries due to over-harvesting, climate change, and/or human impact, our procedure offers a tool for the re-introduction of in vitro-raised plants to threatened areas.

Interaction With Fungi Promotes the Accumulation of Specific Defense Molecules in Orchid Tubers and May Increase the Value of Tubers for Biotechnological and Medicinal Applications: The Case Study of Interaction Between Dactylorhiza sp. and Tulasnella calospora

Terrestrial orchids can form tubers, organs modified to store energy reserves. Tubers are an attractive source of nutrients, and salep, a flour made from dried orchid tubers, is the source of traditional beverages. Tubers also contain valuable secondary metabolites and are used in traditional medicine. The extensive harvest of wild orchids is endangering their populations in nature; however, orchids can be cultivated and tubers mass-produced. This work illustrates the importance of plant-fungus interaction in shaping the content of orchid tubers in vitro. Orchid plants of Dactylorhiza sp. grown in asymbiotic culture were inoculated with a fungal isolate from Tulasnella calospora group and, after 3 months of co-cultivation, tubers were analyzed. The fungus adopted the saprotrophic mode of life, but no visible differences in the morphology and biomass of the tubers were detected compared to the mock-treated plants. To elucidate the mechanisms protecting the tubers against fungal infestation, proteome, metabolome, and lipidome of tubers were analyzed. In total, 1,526, 174, and 108 proteins, metabolites, and lipids were quantified, respectively, providing a detailed snapshot of the molecular process underlying plant-microbe interaction. The observed changes at the molecular level showed that the tubers of inoculated plants accumulated significantly higher amounts of antifungal compounds, including phenolics, alkaloid Calystegine B2, and dihydrophenanthrenes. The promoted antimicrobial effects were validated by observing transient inhibition of Phytophthora cactorum growth. The integration of omics data highlighted the promotion of flavonoid biosynthesis, the increase in the formation of lipid droplets and associated production of oxylipins, and the accumulation of auxin in response to T. calospora. Taken together, these results provide the first insights into the molecular mechanisms of defense priming in orchid tubers and highlight the possible use of fungal interactors in biotechnology for the production of orchid secondary metabolites.