Mentha aquatica (Water Mint) as a Source of Active Pharmaceutical and Cosmetic Ingredients: A Critical Review.

Mentha aquatica L., or water mint, is an important member of the Mentha genus, and has long been used in traditional medicine, mainly to treat respiratory diseases such as the common cold. Nevertheless, although over the years many studies have shown that it's potential grows beyond this use, a review that highlights M. aquatica L.'s true potential is still lacking. Thus, the main purpose of the present article is to provide a thorough and multidisciplinary critical review of M. aquatica L., including its phytochemical characterization, main bioactivities, and current marketed cosmetic products. Many compounds have been identified as part of M. aquatica L. composition, such as terpenes, phenolic acids, phenols, and terpenoids, which have been linked to a vast therapeutic potential, namely anti-inflammatory, antioxidant, antibacterial, antifungal, antiobesity, and hepatoprotection bioactivities, with additional anticancer potential for several types of tumors (breast, lung, and skin), and psycho and neuroactive potential in depression, or Alzheimer's or Parkinson's disease. Additionally, it has been proven to be suitable for cosmetic application since several cleansing, hydrating, protecting, and/or odor masking products containing it are already available, with the main functions attributed to M. aquatica including refreshing/cooling effects, calming/soothing/relaxing effects, and purifying effects, properties closely related to its anti-inflammatory and antioxidant bioactivities. Hence, M. aquatica is an extremely versatile plant, with its extracts and essential oils having great therapeutic and cosmetic potential. With many marketed cosmetic products, future studies should focus on this plant's medicinal aspects, so that 1 day it can be part of therapeutic regimens.

Functional Identification of the Terpene Synthase Family Involved in Biosynthesis in Paeonia lactiflora.

The root of Paeonia lactiflora pall. is a significant component of traditional Chinese medicine, with terpenoids and their glycosides, such as paeoniflorins, serving as key active ingredients known for their anti-inflammatory, hepatoprotective, and analgesic properties. By generating a transcriptome and functionally characterizing 32 terpene synthases (TPSs) from P. lactiflora, we successfully constructed 24 pESC-Trp-PlTPS expression vectors. Through expression in Saccharomyces cerevisiae engineered strains, we identified four mono-TPSs and five sesqui-TPSs that produce 18 compounds, including eight monoterpenes and ten sesquiterpenes in vitro. This includes a bifunctional enzyme (PlTPS22). Additionally, PlTPS21 was characterized as a pinene synthase with α-pinene as its main product. The expression pattern of PlTPS21 aligns closely with the accumulation patterns of paeoniflorins and α-pinene in the plant, suggesting that PlTPS21 is a key enzyme in the biosynthesis of paeoniflorin.

Insights into terpenes profiling and transcriptional analyses during flowering of different Cannabis sativa L. chemotypes.

Terpenes, volatile compounds known for their aromatic and therapeutic properties, play a pivotal role in shaping the overall chemical profile of Cannabis sativa L. Their biosynthesis in planta occurs in trichomes and involves the 2-C-methyl-D-erythritol 4-phosphate (MEP) and the mevalonic acid (MVA) pathways, responsible for producing the substrates utilized by a family of enzymes, the terpene synthases (TPS), for terpene production. In this work, a comprehensive approach combining chemical analyses of the volatile compounds characterizing the aroma of the inflorescences three C. sativa genotypes collected at three stages of maturity and the transcriptional analyses of key genes involved in the terpene biosynthesis was adopted to study this pathway. The results revealed different terpene profiles among genotypes, which were characterized by peculiar compounds belonging to the sesqui- (CINBOL and Fibrante) or monoterpene (Ermo) categories. Both structural and putative regulatory genes were analysed by RT-qPCR, revealing distinct transcriptional profiles of Terpene Synthases, contributing to the diversity of mono and sesquiterpenes synthesized. Furthermore, the research delved into potential regulatory genes associated with trichome formation, a crucial factor influencing terpene accumulation. This integrated approach highlighted complex mechanisms governing terpene accumulation in cannabis, while also offering potential regulators putatively involved in this pathway.

Elicitor-mediated simultaneous accumulation of phloridzin and ursolic acid in Annurca apple peel-derived calli.

BACKGROUND: Apple peel is rich in natural molecules, many exhibiting a significant bioactivity. In this study, our objective was to establish a novel callus line derived from the apple peel of the Italian local variety Annurca, known to accumulate high levels of dihydrochalcones and terpenes. In this regard, we tested the impact of one elicitor, yeast extract, on the expression of genes encoding key enzymes involved in phloridzin and ursolic acid biosynthesis, leading to the accumulation of these antioxidant compounds. We also assessed the bioactivity of callus extracts enriched in these phytochemicals. RESULTS: After the elicitation, data showed increased expression of genes directly related to the synthesis of phloridzin and ursolic acid that were found to accumulate within the cultures. This presumably could explain the remarkable activity of extracts from the elicited-calli in inhibiting the growth of Staphylococcus aureus and Bacillus cereus. Also, the extracts enriched in antioxidant compounds inhibited reactive oxygen species (ROS) production in human cells exposed to ultraviolet-A (UV-A) radiation. CONCLUSION: Our results underscore the vast potential of the Annurca apple peel cell line in producing natural compounds that can be employed as food components to promote human health. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The Efficacy of Orange Terpene and Bacillus mycoides Strain BM103 on the Control of Periwinkle Leaf Yellowing Phytoplasma.

Phytoplasmas are obligate phytopathogenic bacteria belonging to the class Mollicutes. The pathogens, transmitted by insect vectors, associated with hundreds of plant diseases worldwide. Due to the regulation on banning use of antibiotics and limited efficacy of the traditional disease management manners, an eco-friendly alternative is needed. Given that terpene and probiotics have antibiotic activity and the ability to induce systemic resistance, in this study, the effectiveness of orange terpene and a Bacillus mycoides strain, BM103, was evaluated in periwinkle plants infected with periwinkle leaf yellowing (PLY) phytoplasma derived from a shoot-tip tissue culture system. Weekly drenching of 1,000 ppm diluted orange terpene emulsion or pre-activated strain BM103 liquid culture dilution exhibited the ability to inhibit PLY phytoplasma accumulation. The expression of the genes associated with plant defense response and flower development was upregulated after treatment. Moreover, pre-treatment of orange terpene or strain BM103 delayed PLY infection via cleft-grafting inoculation. While orange terpene did not suppress the symptoms, strain BM103 did result in a milder symptom expression that might partially attribute to its plant growth-promoting characteristics. Additionally, the pre-activation of strain BM103 may contribute to its efficacy. Taken together, this research indicates that orange terpene and B. mycoides BM103, with the ability to rapidly induce plant defense responses, could potentially be developed into biological control materials as preventive agents or biofertilizers.

Identifying sesterterpenoids via feature-based molecular networking and small-scale fermentation.

Terpenoids are known for their diverse structures and broad bioactivities with significant potential in pharmaceutical applications. However, natural products with low yields are usually ignored in traditional chemical analysis. Feature-based molecular networking (FBMN) was developed recently to cluster compounds with similar skeletons, which can highlight trace amounts of unknown compounds. Fusoxypene A is a sesterterpene synthesized by Fusarium oxysporum fusoxypene synthase (FoFS) with a unique 5/6/7/3/5 ring system. In this study, the FoFS-containing biosynthetic gene cluster was identified from F. oxysporum FO14005, and an efficient FBMN-based strategy was established to characterize four new sesterterpenoids, fusoxyordienoid A-D (1-4), based on a small-scale fermentation strategy. A cytochrome P450 monooxygenase, FusB, was found to be involved in the functionalization of fusoxypene A at C-17 and C-24 and responsible for the hydroxylation of fusoxyordienoid A at C-1 and C-8. This study highlights the potential of FBMN as a powerful tool for the discovery and characterization of natural compounds with low abundance. KEY POINTS: Combined small-scale fermentation and FBMN for rapid discovery of fusoxyordienoids Characterization of four new fusoxyordienoids with 5/6/7/3/5 ring system Biosynthetic pathway elucidation via tandem expression and substrate feeding.

[Terpene synthase gene family in Jasminum sambac var. Fuzhou bifoliatum: genome-wide analysis and expression pattern in response to methyl jasmonate].

Terpene synthases (TPSs) play a crucial role in the synthesis of terpenoids that contribute to the scent profiles of flowers. However, few studies report the genome-wide analysis of TPSs gene in Jasminum sambac var. Fuzhou bifoliatum and their expression pattern in response to methyl jasmonate (MeJA). In this study, we employed bioinformatics tools for genome-wide analysis of the J. sambac TPS (DJTPS) gene family and determined the physical and chemical properties, subcellular location, protein-protein interactions, phylogenetic relationship, subfamily classification, chromosomal location and collinearity, gene structure, conserved motifs, and promoter cis-acting elements. The expression patterns of DJTPSs in different tissues and in response to MeJA treatment were analyzed based on the transcriptome data combined with quantitative real-time PCR (qRT-PCR). We identified 32 intact DJTPS genes in the genome of J. sambac, which presented uneven distribution across nine chromosomes. All the deduced proteins were hydrophilic, predominantly localized in the cytoplasm. The phylogenetic analysis classified the DJTPS genes into five subfamilies: TPS-a, TPS-b, TPS-c, TPS-e/f, and TPS-g. The results of the collinearity analysis showed a total of 10 sets of replication events in DJTPSs, most of which underwent purifying selection. A comparative analysis of TPS homologous gene pairs was performed among J. sambac var. Fuzhou bifoliatum and other six species, which revealed different number of homologous gene pairs. The number of exons and motifs was conserved within the same subfamily. DJTPS genes carried multiple elements that may be involved in the response to MeJA. In addition, the transcriptome and qRT-PCR data unveiled that several TPS genes exhibited tissue-specific expression patterns, and the genes with specific expression in flowers were the most. Upon exposure to MeJA, 14 TPS genes showcased upregulated expression 5 h or 6 h post-treatment, and DJTPS03, DJTPS04 and DJTPS21 showed significantly increased expression levels after MeJA treatment. This study provides preliminary evidence that MeJA possesses the ability to enhance the expression of DJTPS genes during the critical flowering stage, which will facilitate the synthesis of terpenoids and improve the quality of floral fragrance.

(E)-ß-Farnesene Protects Rice from Rice Striped Stem Borer Attack by Inhibiting Its Beneficial Gut Microbes.

Herbivores harbor gut microbes that affect their development and contribute to their nutrition, reproduction, and survival. Plant defenses could target the herbivore's beneficial gut microbes, but this has not been well studied in rice. In this context, we identified a rice terpene synthase gene, Os04g0341500. It was strongly induced after feeding by rice striped stem borers (SSB, Chilo suppressalis), and it can catalyze the (E)-ß-farnesene (Eßf) synthesis. When added to artificial diets, Eßf impaired the development and survival of SSB larvae. High-throughput amplicon sequencing revealed that SSB fed on Eßf were decreased in beneficial gut microbes, compared to those feeding on the corresponding control feed. In vitro feeding of Eßf suggested that this antimicrobial sesquiterpene directly inhibited the growth of SSB gut microbes. The present study suggested that the Eßf-induced decrease of relative abundance of gut microbes potentially impairs larval development and survival in SSB.

Ashbya gossypii as a versatile platform to produce sabinene from agro-industrial wastes.

BACKGROUND: Ashbya gossypii is a filamentous fungus widely utilized for industrial riboflavin production and has a great potential as a microbial chassis for synthesizing other valuable metabolites such as folates, biolipids, and limonene. Engineered strains of A. gossypii can effectively use various waste streams, including xylose-rich feedstocks. Notably, A. gossypii has been identified as a proficient biocatalyst for producing limonene from xylose-rich sources. This study aims to investigate the capability of engineered A. gossypii strains to produce various plant monoterpenes using agro-industrial waste as carbon sources. RESULTS: We overexpressed heterologous terpene synthases to produce acyclic, monocyclic, and bicyclic monoterpenes in two genetic backgrounds of A. gossypii. These backgrounds included an NPP synthase orthogonal pathway and a mutant erg20F95W allele with reduced FPP synthase activity. Our findings demonstrate that A. gossypii can synthesize linalool, limonene, pinene, and sabinene, with terpene synthases showing differential substrate selectivity for NPP or GPP precursors. Additionally, co-overexpression of endogenous HMG1 and ERG12 with heterologous NPP synthase and terpene synthases significantly increased sabinene yields from xylose-containing media. Using mixed formulations of corn-cob lignocellulosic hydrolysates and either sugarcane or beet molasses, we achieved limonene and sabinene productions of 383 mg/L and 684.5 mg/L, respectively, the latter representing a significant improvement compared to other organisms in flask culture mode. CONCLUSIONS: Engineered A. gossypii strains serve as a suitable platform for assessing plant terpene synthase functionality and substrate selectivity in vivo, which are crucial to understand monoterpene bioproduction. The NPP synthase pathway markedly enhances limonene and sabinene production in A. gossypii, achieving levels comparable to those of other industrial microbial producers. Furthermore, these engineered strains offer a novel approach for producing monoterpenes through the valorization of agro-industrial wastes.

Tamariscol biosynthesis in Frullania tamarisci.

The liverwort Frullania tamarisci (L.) Dumort produces large amounts of terpenoids, among others the sesquiterpene alcohol tamariscol. Tamariscol has an earthy woody fragrance, and the use in perfurmes and production of it was patented in 1984. The microbial terpene synthase-like (MTPSL) enzyme FtMTPSL6 is shown to be responsible for the biosynthesis of tamariscol. FtMTPSL6 was obtained through RNA sequencing of wild growing F. tamarisci along with six other MTPSLs (FtMTPSL1-7). The biochemical activity was determined for three of them, and two others where metabolic active, but the product could not be identified. The three characterized enzymes are the tamariscol synthase (FtMTPSL6), copaene synthase (FtMTPSL1) and gurjunene synthase (FtMTPSL3). Thus, the biosynthesis of the economically attractive compound tamariscol is established, and this opens up for further exploitation of this molecule.

Geraniol Inhibits Both Planktonic Cells and Biofilms of the Candida parapsilosis Species Complex: Highlight for the Improved Efficacy of Amphotericin B, Caspofungin and Fluconazole plus Geraniol.

The Candida parapsilosis species complex poses a recognized threat to the nosocomial environment. In the scenario of the global rise of resistant strains to antifungals, geraniol, a terpene isolated from different essential oils, has shown promising antimicrobial activity. We evaluated: 1- the effects of geraniol against the Candida parapsilosis species complex, in planktonic and biofilm forms; 2- the strains' susceptibility to clinical antifungals and 3- the geraniol interaction with antifungals. Eighteen isolates were subjected to in vitro susceptibility testing by the broth microdilution protocol, using geraniol, amphotericin B, caspofungin, itraconazole and fluconazole to determine the minimum inhibitory concentration (MIC) and subsequently we measured the fungicidal activity. Geraniol was tested against biofilms by the measurement of the metabolic activity and biomass. Pharmacological interactions were performed by the checkerboard method. Geraniol's MIC range was between 256 and 512 µg/ml. MIC range for clinical antifungals was ≤ 0.031-4 µg/ml. Geraniol also showed antibiofilm activity with average reductions of metabolic activity (38.33%) and biomass (30.69%), at MIC concentration. Furthermore, geraniol showed synergistic/additive effects with antifungals. Briefly, geraniol inhibits both planktonic cells and biofilms of the Candida parapsilosis species complex and besides it improves the efficacy of amphotericin B, caspofungin and fluconazole.

Geraniol inhibits Candida parapsilosis species complex both in planktonic and biofilm growth. In addition, it shows synergistic/additive effects with the antifungals amphotericin B and caspofungin, besides additive activity with fluconazole.

Iron-Containing Seed Particles Enhance α-Pinene Secondary Organic Aerosol Mass Concentration and Dimer Formation.

Secondary organic aerosol (SOA) comprises the majority of submicron particles and is important for air pollution, health, and climate. When SOA mixes with inorganic particles containing transition metals (e.g., Fe), chemical reactions altering physicochemical properties can occur. Here, we study Fe's impact on the formation and chemical composition of SOA formed via dark α-pinene ozonolysis on either (NH4)2SO4 or Fe-containing (NH4)2SO4 seed particles and aged at varying relative humidities (RHs). Aerosol composition was determined using online extractive electrospray ionization mass spectrometry, providing high-resolution chemical and temporal identification of monomers and dimers in the SOA. At high RH, Fe's presence resulted in higher particulate SOA mass concentrations (117 ± 14 µg m-3) than those formed in its absence (70 ± 1 µg m-3). Enhanced mass is coupled with more dimers (C15-20's), attributed to Fenton-driven oligomerization reactions. Experiments with Fe3+-containing seeds showed similar chemical composition and enhanced SOA mass, suggesting a dark reduction pathway to form Fe2+ in the presence of SOA. Overall, Fe's presence at high RH lowers SOA volatility and enhances particulate organic mass and condensed phased reactions of higher volatility species that would normally not participate in SOA formation, which may be important when considering its formation in air quality and climate models.

The Legacy Effect of Mountain Pine Beetle Outbreaks on the Chemical and Anatomical Defences of Surviving Lodgepole Pine Trees.

The recent mountain pine beetle outbreaks have caused widespread mortality among lodgepole pine trees in western North America, resulting in a reduced population of surviving trees. While previous studies have focused on the cascading impacts of these outbreaks on the physiology and growth of the surviving trees, there remains a need for a comprehensive study into the interactions among various physiological traits and the growth in post-outbreak stands. Specifically, the relationship between chemical (primarily terpenes) and anatomical (mainly resin ducts) defences, as well as the allocation of non-structural carbohydrates (NSCs) to support these defence modalities, is poorly understood. To address these gaps, we conducted a field survey of surviving lodgepole pine trees in post-mountain pine beetle outbreak stands in western Canada. Our retrospective analysis aimed at determining correlations between the post-outbreak concentrations of monoterpenes, diterpenes, and NSCs in the phloem and the historical resin duct characteristics and growth traits before and after the outbreak. We detected strong correlations between the post-outbreak concentrations of monoterpenes and historical resin duct characteristics, suggesting a possible link between these two defence modalities. Additionally, we found a positive relationship between the NSCs and the total concentrations of monoterpenes and diterpenes, suggesting that NSCs likely influence the production of these terpenes in lodgepole pine. Furthermore, historical tree growth patterns showed strong positive correlations with many individual monoterpenes and diterpenes. Interestingly, while surviving trees had enhanced anatomical defences after the outbreak, their growth patterns did not vary before and after the outbreak conditions. The complexity of these relationships emphasizes the dynamics of post-outbreak stand dynamics and resource allocations in lodgepole pine forests, highlighting the need for further research. These findings contribute to a broader understanding of conifer defences and their coordinated responses to forest insect outbreaks, with implications for forest management and conservation strategies.

Evaluation of molecular interaction between intercellular lipid organization in human stratum corneum and terpenes using time-resolved synchrotron X-ray diffraction.

The stratum corneum (SC) presents certain limitations for topical administration of medication, which can be overcome using penetration enhancers (PEs) such as terpene (TP). The SC is also crucial for maintaining the skin barrier and consists of two lamellar structures: the short periodicity phase (SPP) and long periodicity phase (LPP). In this study, we monitored changes in the X-ray diffraction peaks of the human SC, 30 min after TP application (neroridol, 1,8-cineol, and d-limonene). With the application of nerolidol, no significant changes were observed in the small-angle diffraction peak positions for the lamellar structure of SPP, but the integrated intensity decreased. On the contrary, when applying 1,8-cineole and d-limonene, a lower angle peak shift with broadening of the peak width of SPP diffraction peaks was observed for d-limonene than for 1,8-cineole, and the degree of peak shift and width broadening was greater for d-limonene than for 1,8-cineole. The diffraction peaks of LPP disappeared when 1,8-cineole and d-limonene were applied. These results indicate that the degree of interaction between the SC and TP differs depending on the molecular species, and d-limonene and 1,8-cineole exhibit penetration-enhancing via lamellar structure disruption of both SPP and LPP, immediately after application.

RAIChU: automating the visualisation of natural product biosynthesis.

Natural products are molecules that fulfil a range of important ecological functions. Many natural products have been exploited for pharmaceutical and agricultural applications. In contrast to many other specialised metabolites, the products of modular nonribosomal peptide synthetase (NRPS) and polyketide synthase (PKS) systems can often (partially) be predicted from the DNA sequence of the biosynthetic gene clusters. This is because the biosynthetic pathways of NRPS and PKS systems adhere to consistent rulesets. These universal biosynthetic rules can be leveraged to generate biosynthetic models of biosynthetic pathways. While these principles have been largely deciphered, software that leverages these rules to automatically generate visualisations of biosynthetic models has not yet been developed. To enable high-quality automated visualisations of natural product biosynthetic pathways, we developed RAIChU (Reaction Analysis through Illustrating Chemical Units), which produces depictions of biosynthetic transformations of PKS, NRPS, and hybrid PKS/NRPS systems from predicted or experimentally verified module architectures and domain substrate specificities. RAIChU also boasts a library of functions to perform and visualise reactions and pathways whose specifics (e.g., regioselectivity, stereoselectivity) are still difficult to predict, including terpenes, ribosomally synthesised and posttranslationally modified peptides and alkaloids. Additionally, RAIChU includes 34 prevalent tailoring reactions to enable the visualisation of biosynthetic pathways of fully maturated natural products. RAIChU can be integrated into Python pipelines, allowing users to upload and edit results from antiSMASH, a widely used BGC detection and annotation tool, or to build biosynthetic PKS/NRPS systems from scratch. RAIChU's cluster drawing correctness (100%) and drawing readability (97.66%) were validated on 5000 randomly generated PKS/NRPS systems, and on the MIBiG database. The automated visualisation of these pathways accelerates the generation of biosynthetic models, facilitates the analysis of large (meta-) genomic datasets and reduces human error. RAIChU is available at https://github.com/BTheDragonMaster/RAIChU and https://pypi.org/project/raichu .Scientific contributionRAIChU is the first software package capable of automating high-quality visualisations of natural product biosynthetic pathways. By leveraging universal biosynthetic rules, RAIChU enables the depiction of complex biosynthetic transformations for PKS, NRPS, ribosomally synthesised and posttranslationally modified peptide (RiPP), terpene and alkaloid systems, enhancing predictive and analytical capabilities. This innovation not only streamlines the creation of biosynthetic models, making the analysis of large genomic datasets more efficient and accurate, but also bridges a crucial gap in predicting and visualising the complexities of natural product biosynthesis.

Co-Infection with Nocardia Terpene and Pneumocystis Jirovecii in a Patient with Anti-Synthetase Syndrome: A Case Report.

Background: Pulmonary infection is a common clinical complication associated with glucocorticoid. There have been no reported cases of mixed infections involving Nocardia and Pneumocystis jirovecii combined with anti-synthetase syndrome (ASS) activity. Methods: This study conducted a retrospective analysis of the clinical data from a patient with active ASS, treated for a pulmonary coinfection. Results: The patient exhibited fever, asthma, and cough as initial symptoms. Chest CT scan revealed multiple infiltration shadows, consolidation shadows, nodules, mass shadows, and internal cavities in both lungs. BALF mNGS detected Nocardia terpene and Pneumocystis jiroveci. Treatment with sulfamethoxazole/trimethoprim and corticosteroids led to an improvement. However, the patient experienced recurrent fever and a new rash with the reduction of the glucocorticoid dosage. Further investigation identified positive anti-Jo-1 and anti-Ro-52 antibodies and myogenic lesions on electromyography, which confirmed the diagnosis of ASS. Following treatment with immunoglobulin, methylprednisolone, and cyclosporine, the patient's condition significantly improved. Conclusion: Immunodeficiency patients are susceptible to opportunistic infections. mNGS is valuable for diagnosis and treatment. Although the image of Nocardia terpene and Pneumocystis jiroveci infections lack specificity, they exhibit distinctive features. Should fever and skin lesions reoccur post-effective anti-infective therapy, it is imperative to explore non-infectious causes and expedite autoantibody testing.

The Gongora gibba genome assembly provides new insights into the evolution of floral scent in male euglossine bee-pollinated orchids.

Orchidaceae is one of the most prominent flowering plant families, with many species exhibiting highly specialized reproductive and ecological adaptations. An estimated 10% of orchid species in the American tropics are pollinated by scent-collecting male euglossine bees; however, to date, there are no published genomes of species within this pollination syndrome. Here we present the first draft genome of an epiphytic orchid from the genus Gongora, a representative of the male euglossine bee-pollinated subtribe Stanhopeinae. The 1.83 Gb de novo genome with a scaffold N50 of 1.7Mb was assembled using short- and long-read sequencing and chromosome capture (Hi-C) information. Over 17,000 genes were annotated, and 82.95% of the genome was identified as repetitive content. Furthermore, we identified and manually annotated 26 terpene synthase (TPS) genes linked to floral scent biosynthesis and performed a phylogenetic analysis with other published orchid TPS genes. The Gongora gibba genome assembly will serve as the foundation for future research to understand the genetic basis of floral scent biosynthesis and diversification in orchids. Las orquídeas (Orchidaceae) son una de las familias de plantas con mayor riqueza de especies y exhiben adaptaciones reproductivas altamente especializadas. Se estima que el 10% de las especies de orquídeas en los trópicos americanos son polinizadas por abejas euglosinas; sin embargo, hasta la fecha no existen genomas publicados de especies con este síndrome de polinización. Aquí presentamos el primer genoma de una orquídea epífita del género Gongora, un representante de la subtribu Stanhopeinae, que es polinizada exclusivamente por abejas euglosinas macho. El genoma de 1,83 Gb se ensambló de novo utilizando secuenciación e información de captura de cromosomas (Hi-C), logrando un N50 de 1,7 Mb. Se anotaron más de 17.000 genes y se identificó que el 82,95% del genoma presenta elementos repetitivos. Además, identificamos y anotamos manualmente 26 genes de la familia de genes terpeno sintasa (TPS) y realizamos un análisis filogenético con otros genes TPS de orquídeas publicados. El ensamblaje del genoma de Gongora gibba servirá como base para futuras investigaciones para comprender la base genética de la biosíntesis y la diversificación de los aromas florales en las orquídeas.

Isolation and characterisation of sesquiterpene synthase from aromatic orchid Phalaenopsis bellina (Rchb.f.) Christenson.

BACKGROUND: Phalaenopsis bellina, an orchid native to Borneo, is renowned for its unique appearance. It releases distinct fragrances, which have been linked to the presence of terpenoids. However, the identification and study of sesquiterpene synthase in P. bellina remain limited. In this study, we examines the functional characterisation of terpene synthase (TPS) from P. bellina, known as PbTS, through recombinant protein expression and its manifestation in the flower. METHODS AND RESULTS: Gene annotation of PbTS revealed that the inferred peptide sequence of PbTS comprises 1,680 bp nucleotides encoding 559 amino acids with an estimated molecular mass of 65.2 kDa and a pI value of 5.4. A similarity search against GenBank showed that PbTS shares similarities with the previously published partial sequence of P. bellina (ABW98504.1) and Phalaenopsis equestris (XP_020597359.1 and ABW98503.1). Intriguingly, the phylogenetic analysis places the PbTS gene within the TPS-a group. In silico analysis of PbTS demonstrated stable interactions with farnesyl pyrophosphate (FPP), geranyl pyrophosphate (GPP), and geranylgeranyl pyrophosphate (GGPP). To verify this activity, an in vitro enzyme assay was performed on the PbTS recombinant protein, which successfully converted FPP, GPP, and GGPP into acyclic sesquiterpene ß-farnesene, yielding approximately 0.03 mg/L. Expressional analysis revealed that the PbTS transcript was highly expressed in P. bellina, but its level did not correlate with ß-farnesene levels across various flowering time points and stages. CONCLUSION: The insights gained from this study will enhance the understanding of terpenoid production in P. bellina and aid in the discovery of novel fragrance-related genes in other orchid species.

Chemometric analysis of monoterpenes and sesquiterpenes of conifers.

Volatile organic compounds (VOCs) and essential oils of conifers are widely used in the pharmaceutical industry. This work aimed to analyze the VOCs of 30 conifer species representing the Pinaceae and Cupressaceae families. Samples were collected from arboreta in Hungary, and their chemical composition was determined by gas chromatography (SPME-GC/MS); then, chemometric analyses were performed using multivariate methods to identify characteristic VOCs of conifers. Here, we present results for monoterpene and sesquiterpene profiles of the examined conifer samples. The most abundant compounds detected were α-pinene, bornyl acetate, limonene, ß-pinene, ß-caryophyllene, ß-myrcene, δ-3-carene, and ß-phellandrene. The results showed that the following volatiles were characteristic of the conifer groups: sabinene (RRT=6.0) for the cupressoid group (which includes the Cupressaceae species), longifolene (RRT=15.0) and ß-pinene (RRT=6.1) were characteristic of the pinoid group (including Picea, Pinus, and Pseudotsuga species), and camphene (RRT=5.5) and bornyl acetate (RRT=12.6) were characteristic of the abietoid group (including Abies, Cedrus, and Tsuga species). Our results on VOCs in the Pinaceae and Cupressaceae families contribute to the elucidation of biodiversity patterns of conifer species and, in addition, may support the industrial application of terpenes.

Bursaphelenchus xylophilus Venom Allergen-Like Protein BxVAP1, Triggering Plant Defense-Related Programmed Cell Death, Plays an Important Role in Regulating Pinus massoniana Terpene Defense Responses.

Bursaphelenchus xylophilus (pine wood nematode, PWN), a migratory plant-parasitic nematode, acts as an etiological agent, inflicting considerable damage to pine forests worldwide. Plant immunity constitutes a crucial factor in resisting various pathogenic invasions. The primary defensive responses of host pines against PWN infection encompass terpene accumulation, defense response-related gene expression, and programmed cell death. Venom allergen-like proteins (VAPs), as potential effectors, are instrumental in facilitating the successful colonization of PWNs. In this study, we investigated the inhibition of B. xylophilus VAP (BxVAP1) expression by RNA interference in vitro. Following BxVAP1 silencing, the reproduction rate and migration rate of the PWN population in Pinus massoniana decreased, the expression of the α-pinene synthase gene was induced, other terpene synthase and pathogenesis-related genes were inhibited and delayed, the peak times and levels of terpene-related substances were changed, and the degree of cavitation in P. massoniana was diminished. Transient expression of BxVAP1 in Nicotiana benthamiana revealed that BxVAP1 was expressed in both the cell membrane and nucleus, inducing programmed cell death and the expression of pathogen-associated molecular pattern-triggered immunity marker genes (NbAcre31 and NbPTI5). This study is the first to demonstrate that silencing the BxVAP1 gene affects host defense responses, including terpenoid metabolism in P. massoniana, and that BxVAP1 can be recognized by N. benthamiana as an effector to trigger its innate immunity, expanding our understanding of the parasitic mechanism of B. xylophilus.