Core microbiota drive multi-functionality of the soil microbiome in the Cinnamomum camphora coppice planting.

BACKGROUND: Cinnamomum camphora (L.) Presl (C. camphora) is an evergreen broad-leaved tree cultivated in subtropical China. The use of C. camphora as clonal cuttings for coppice management has become popular recently. However, little is known about the relationship between soil core microbiota and ecosystem multi-functionality under tree planting. Particularly, the effects of soil core microbiota on maintaining ecosystem multi-functionality under C. camphora coppice planting remained unclear. MATERIALS AND METHODS: In this study, we collected soil samples from three points (i.e., the abandoned land, the root zone, and the transition zone) in the C. camphora coppice planting to investigate whether core microbiota influences ecosystem multi-functions. RESULTS: The result showed a significant difference in soil core microbiota community between the abandoned land (AL), root zone (RZ), and transition zone (TZ), and soil ecosystem multi-functionality of core microbiota in RZ had increased significantly (by 230.8%) compared to the AL. Soil core microbiota played a more significant influence on ecosystem multi-functionality than the non-core microbiota. Moreover, the co-occurrence network demonstrated that the soil ecosystem network consisted of five major ecological clusters. Soil core microbiota within cluster 1 were significantly higher than in cluster 4, and there is also a higher Copiotrophs/Oligotrophs ratio in cluster 1. Our results corroborated that soil core microbiota is crucial for maintaining ecosystem multi-functionality. Especially, the core taxa within the clusters of networks under tree planting, with the same ecological preferences, had a significant contribution to ecosystem multi-functionality. CONCLUSION: Overall, our results provide further insight into the linkage between core taxa and ecosystem multi-functionality. This enables us to predict how ecosystem functions respond to the environmental changes in areas under the C. camphora coppice planting. Thus, conserving the soil microbiota, especially the core taxa, is essential to maintaining the multiple ecosystem functions under the C. camphora coppice planting.

The potential of Bacillus species isolated from Cinnamomum camphora for biofuel production.

BACKGROUND: Increasing concerns about climate change and global petroleum supply draw attention to the urgent need for the development of alternative methods to produce fuels. Consequently, the scientific community must devise novel ways to obtain fuels that are both sustainable and eco-friendly. Bacterial alkanes have numerous potential applications in the industry sector. One significant application is biofuel production, where bacterial alkanes can serve as a sustainable eco-friendly alternative to fossil fuels. This study represents the first report on the production of alkanes by endophytic bacteria. RESULTS: In this study, three Bacillus species, namely Bacillus atrophaeus Camph.1 (OR343176.1), Bacillus spizizenii Camph.2 (OR343177.1), and Bacillus aerophilus Camph.3 (OR343178.1), were isolated from the leaves of C. camphora. The isolates were then screened to determine their ability to produce alkanes in different culture media including nutrient broth (NB), Luria-Bertani (LB) broth, and tryptic soy broth (TSB). Depending on the bacterial isolate and the culture media used, different profiles of alkanes ranging from C8 to C31 were detected. CONCLUSIONS: The endophytic B. atrophaeus Camph.1 (OR343176.1), B. spizizenii Camph.2 (OR343177.1), and B. aerophilus Camph.3 (OR343178.1), associated with C. camphora leaves, represent new eco-friendly approaches for biofuel production, aiming towards a sustainable future. Further research is needed to optimize the fermentation process and scale up alkane production by these bacterial isolates.

The Key Phytochemical Cue Camphor Is a Promising Lure for Traps Monitoring the New Monophagous Camphor Tree Borer Pagiophloeus tsushimanus (Coleoptera: Curculionidae).

The landscape plant, Cinnamomum camphora, is a broad-spectrum insect-repelling tree species, mainly due to a diversity of terpenoids, such as camphor. Despite its formidable chemical defenses, C. camphora is easily attacked and invaded by a monophagous weevil pest, Pagiophloeus tsushimanus. Deciphering the key olfactory signal components regulating host preference could facilitate monitoring and control strategies for this pest. Herein, two host volatiles, camphor and ocimene, induced GC-EAD/EAG reactions in both male and female adult antennae. Correspondingly, Y-tube olfactometer assays showed that the two compounds were attractive to both male and female adults. In field assays, a self-made trap device baited with 5 mg dose d(+)-camphor captured significantly more P. tsushimanus adults than isopropanol solvent controls without sexual bias. The trunk gluing trap device baited with bait can capture adults, but the number was significantly less than that of the self-made trap device and adults often fell after struggling. The cross baffle trap device never trapped adults. Neither ocimene nor isopropanol solvent control captured adults. When used in combination, ocimene did not enhance the attraction of d(+)-camphor to both female and male adults. These results indicate that d(+)-camphor is a key active compound of P. tsushimanus adults for host location. The combination of the host-volatile lure based on d(+)-camphor and the self-made trapping device is promising to monitor and provide an eco-friendly control strategy for this novel pest P. tsushimanus in C. camphora plantations.

Identification of algicidal monoterpenoids from four chemotypes of Cinnamomum camphora and their algicidal mechanisms on Microcystis aeruginosa.

Cyanobacterial blooms cause serious environmental issues, and plant secondary metabolites are considered as new algaecide for controlling them. Cinnamomum camphora produces a wide spectrum of terpenoids and has 4 main chemotypes, including linalool, camphor, eucalyptol and borneol chemotype. To develop the new cyanobacterial algaecide by using suitable chemotype of Cinnamomum camphora and the main terpenoids, we analyzed the terpenoid composition in the 4 chemotype extracts, evaluated the algicidal effects of the extracts and their typical monoterpenoids on Microcystis aeruginosa, and investigated the algicidal mechanism of the stronger algicidal agents. Among the 4 chemotypes, eucalyptol and borneol chemotype extracts exhibited stronger algicidal effects. In the 4 chemotype extracts, monoterpenoids were the main compounds, of which linalool, camphor, eucalyptol and borneol were the typical components. Among the 4 typical monoterpenoids, eucalyptol and borneol showed stronger algicidal effects, which killed 78.8% and 100% M. aeruginosa cells, respectively, at 1.2 mM after 48 h. In 1.2 mM eucalyptol and borneol treatments, the reactive oxygen species levels markedly increased, and the caspase-3-like activity also raised. With prolonging the treatment time, M. aeruginosa cells gradually shrank and wrinkled, and the cell TUNEL fluorescence intensity and DNA degradation gradually enhanced, indicating that the lethal mechanism is causing apoptosis-like programmed cell death (PCD). Therefore, eucalyptol and borneol chemotype extracts and their typical monoterpenoids have the potential for developing as algaecides to control cyanobacteria through triggering apoptosis-like PCD.

Unraveling the complex evolutionary features of the Cinnamomum camphora mitochondrial genome.

KEY MESSAGE: We reported the mitochondrial genome of Cinnamomum camphora for the first time, revealing frequent rearrangement events in the non-coding regions of Magnoliids mitochondrial genomes. As one of the representative species in the Lauraceae family of Magnoliids, Cinnamomum camphora holds significant economic and ecological value. In this study, the mitochondrial genome (mitogenome) of C. camphora was complete assembled and annotated using PacBio HiFi sequencing. The C. camphora mitogenome is characterized by a branch structure, spans 900,894 bp, and contains 43 protein-coding genes (PCGs), 24 tRNAs, and 3 rRNAs. Most of these PCGs are under purifying selection, with only two (ccmFc and rps7) exhibiting signs of positive selection. The C. camphora mitogenome contains numerous repetitive sequences and intracellular gene transfers, with a total of 36 mitochondrial plastid DNAs, amounting to a combined length of 23,816 bp. Comparative analysis revealed that the non-coding regions of Magnoliids mitogenomes have undergone frequent rearrangements during evolution, but the coding sequences remain highly conserved (more than 98% similarity for protein-coding sequences). Furthermore, a maximum-likelihood phylogenetic tree was reconstructed based on 25 PCGs from 23 plant mitogenomes. The analysis supports the closest relationship between C. camphora and C. chekiangense, consistent with the APG IV classification system. This study elucidates the unique evolutionary features of the C. camphora mitogenome, which will provide valuable insights into the study of genetics and evolution of the family Lauraceae.

Genome and whole-genome resequencing of Cinnamomum camphora elucidate its dominance in subtropical urban landscapes.

BACKGROUND: Lauraceae is well known for its significant phylogenetic position as well as important economic and ornamental value; however, most evergreen species in Lauraceae are restricted to tropical regions. In contrast, camphor tree (Cinnamomum camphora) is the most dominant evergreen broadleaved tree in subtropical urban landscapes. RESULTS: Here, we present a high-quality reference genome of C. camphora and conduct comparative genomics between C. camphora and C. kanehirae. Our findings demonstrated the significance of key genes in circadian rhythms and phenylpropanoid metabolism in enhancing cold response, and terpene synthases (TPSs) improved defence response with tandem duplication and gene cluster formation in C. camphora. Additionally, the first comprehensive catalogue of C. camphora based on whole-genome resequencing of 75 accessions was constructed, which confirmed the crucial roles of the above pathways and revealed candidate genes under selection in more popular C. camphora, and indicated that enhancing environmental adaptation is the primary force driving C. camphora breeding and dominance. CONCLUSIONS: These results decipher the dominance of C. camphora in subtropical urban landscapes and provide abundant genomic resources for enlarging the application scopes of evergreen broadleaved trees.

A systematic genome-wide analysis and screening of the NAC family genes related to wood formation in Cinnamomum camphora.

Many processes, such as growth, aging, and adaptation to abiotic stress, are regulated in plants by NAC transcription factors. In woody plants, NAC transcription factors acts as a primary switch that regulates secondary xylem development by activating various downstream transcription factors and modulating expression levels of genes involved in the synthesis of the secondary cell wall. Our team had previously sequenced the whole genome of the camphor tree (Cinnamomum camphora). Here, we performed a detailed analysis of the NAC gene family of C. camphora and examined its evolutionary history. The genomic sequences of 121 NAC genes of C. camphora were identified and classified into 20 subfamilies in 2 major classes based on the phylogenetic analysis and structural features. Expansion of the CcNAC gene family occurred mainly by fragment replication and was influenced by the purifying selection. By analyzing predicted interactions of the homologous AtNAC proteins, we identified five CcNACs that potentially regulate xylem development in C. camphora. RNA sequencing revealed distinct expression profiles of CcNACs in seven different plant tissues. Subcellular localization prediction revealed that 120, 3, and 2 CcNACs have biological functions in the nucleus, cytoplasm, and chloroplast, respectively. Furthermore, we verified expression patterns of five CcNACs (CcNAC012, CcNAC028, CcNAC055, CcNAC080, and CcNAC119) in various tissue types using qRT-PCR. Our results will facilitate further in-depth studies of the molecular mechanisms by which CcNAC transcription factors regulate wood formation and other processes in C. camphora.

Transcriptome and Metabolome Analyses of Leaves from Cutting Rejuvenation of Ancient Cinnamomum camphora.

Rejuvenation refers to the transition from the state of mature to juvenile. Many ancient Cinnamomum camphora have aged and died due to climatic and anthropic factors. Vegetative propagation can protect valuable germplasm resources. In this study, a 2000-year-old ancient C. camphora and its 2-year-old cutting plantlets were selected as experimental materials. The results indicated that the number of leaves with palisade tissue (Pal) cell layers was different between samples, with two layers in the rejuvenated leaves (RLs) and one layer in the mature leaves (MLs) and young leaves (YLs). Indole-3-acetic acid (IAA), isopentenyladenine (iP) and isopentenyladenosine (iPR) concentrations were significantly higher in RLs than in MLs and YLs, but the abscisic acid (ABA) concentration was lower. Targeted metabolome analysis identified 293 differentially accumulated metabolites (DAMs). Meanwhile, a total of 5241 differentially expressed genes (DEGs) were identified by transcriptome sequencing. According to the KEGG analysis, there were seven important enriched pathways in the MLs, RLs and YLs, including plant hormone signal transduction (57 DEGs), plant-pathogen interaction (56 DEGs) and MAPK signaling pathway-plant (36 DEGs). KEGG enrichment conjoint analyses of DEGs and DAMs identified 16 common pathways. Integrated analyses of cytological, hormone, metabolome and transcriptome elements can provide a research basis in regard to the rejuvenation regulatory mechanism of ancient C. camphora.

Genome-Wide Analysis and Characterization of the SDR Gene Superfamily in Cinnamomum camphora and Identification of Synthase for Eugenol Biosynthesis.

Short-chain dehydrogenase/reductases (SDRs) are the largest NAD(H)-dependent oxidoreductase superfamilies and are involved in diverse metabolisms. This study presents a comprehensive genomic analysis of the SDR superfamily in Cinnamomum camphora, a species that is one of the most significant woody essential oil plants in southern China. We identify a total of 222 CcSDR proteins and classify them into five types based on their cofactor-binding and active sites: 'atypical', 'classic', 'divergent', 'extended', and 'unknown'. Phylogenetic analysis reveals three evolutionary branches within the CcSDR proteins, and further categorization using the SDR-initiative Hidden Markov model resulted in 46 families, with the CcSDR110C, CcSDR108E, and CcSDR460A families being the most populous. Collinearity analysis identified 34 pairs of CcSDR paralogs in C. camphora, 141 pairs of SDR orthologs between C. camphora and Populus trichocarpa, and 59 pairs between C. camphora and Oryza sativa. Expression profile analysis indicates a preference for the expression of 77 CcSDR genes in specific organs such as flowers, bark, twigs, roots, leaves, or fruits. Moreover, 77 genes exhibit differential expression patterns during the four developmental stages of leaves, while 130 genes show variance across the five developmental stages of fruits. Additionally, to explore the biosynthetic mechanism of methyl eugenol, a key component of the leaf essential oil in the methyl eugenol chemotype, this study also identifies eugenol synthase (EGS) within the CcSDR460A family through an integrated strategy. Real-time quantitative PCR analysis demonstrates that the expression of CcEGS in the leaves of the methyl eugenol chemotype is more than fourfold higher compared to other chemotypes. When heterologously expressed in Escherichia coli, it catalyzes the conversion of coniferyl acetate into a mixture predominantly composed of eugenol (71.44%) and isoeugenol (21.35%). These insights pave the way for future research into the functional diversity of CcSDR genes, with a focus on secondary metabolism.

[Chemical composition and pharmacological effects of Cinnamomum camphora chvar. borneol essential oil: a review].

Cinnamomum camphora chvar. borneol, a rare camphor tree variant recently identified in China, is distinguished by its high concentration of D-borneol, also known as " plant gold" due to its significant value. The essential oil extracted from this variant,rich in monoterpenes and sesquiterpenes, demonstrates a broad spectrum of pharmacological activities, including analgesic, antiinflammatory, antioxidant, cognition-enhancing, anti-bacterial, and insecticidal effects. These properties, underscored by extensive research, highlight the oil's potential in the biomedical, chemical, and food sectors as a valuable commodity. Nonetheless, the safety profile of this valuable oil remains poorly characterized, with its chemical composition and therapeutic efficacy subject to variations in the factors like geographic origin, harvesting timing, part used for extraction, and processing techniques. Such variability poses challenges to its clinical application and hampers the efficient exploitation of this resource. This review synthesizes current studies on C. camphora chvar. borneol essential oil and provides a detailed examination of its chemical and pharmacological profiles. In this study, we discuss existing research gaps and propose strategies for advancing its clinical use and industrial application, aiming to provide a foundational reference for future investigations and the resolution of its commercial and therapeutic challenges.

[Essential oil of Cinnamomum camphora mitigates depression-like behavior in mice by regulating Nrf2/HO-1 pathway and inhibiting inflammatory cytokines].

This study aims to investigate the essential oil(EOL) of Cinnamomum camphora regarding its anti-depression effect and mechanism in regulating inflammatory cytokines and the nuclear factor erythroid 2-related factor 2(Nrf2)/heme oxygenase-1(HO-1) pathway. A mouse model of depression was established by intraperitoneal injection of lipopolysaccharide(LPS). Open field, elevated plus maze, and forced swimming tests were carried out to examine mouse behaviors. Western blot and qRT-PCR were employed to determine the expression of proteins and genes in the Nrf2/HO-1 pathway in the hippocampus. The levels of tumor necrosis factor(TNF)-α, interleukin(IL)-6, and IL-1ß in the serum were measured by enzyme-linked immunosorbent assay(ELISA). The changes of apoptosis in mouse brain were detected by Tunel staining. Compared with the blank control group, the model group showed shortened distance travelled and time spent in the central zone and reduced number of entries in the central zone in the open field test. In the elevated plus maze test, the model group showed reduced open arm time(OT%) and open arm entries(OE%). In the force swimming test, the model group showed extended duration of immobility compared with the blank control group. Compared with the model group, the treatment with EOL significantly increased the distance travelled and time spent in the central zone and increased the number of entries in the central zone in the open field test. In addition, EOL significantly increased the OT% and OE% in the elevated plus maze and shor-tened the immobility duration in the forced swimming test. The model group showed lower expression levels of Nrf2 and HO-1 and hig-her levels of TNF-α, IL-6, and IL-1ß than the blank control group. Compared with the model group, the treatment with EOL up-regulated the expression levels of Nrf2 and HO-1 and lowered the levels of TNF-α, IL-6, and IL-1ß. The Tunel staining results showed that the apoptosis rate in the brain tissue of mice decreased significantly after the treatment with EOL. To sum up, EOL can mitigate the depression-like behaviors of mice by up-regulating the expression of Nrf2 and HO-1 and preventing hippocampal inflammatory damage. The findings provide empirical support for the application of EOL and aromatherapy in the treatment of depression.

Allergic contact dermatitis from essential oil in consumer products: Mode of uses and value of patch tests with an essential oil series. Results of a French study of the DAG (Dermato-Allergology group of the French Society of Dermatology).

OBJECTIVE: To analyse the clinical characteristics and sensitivity of an essential oil patch test series (EOS) in patients sensitized to their own essential oils (EOs). METHOD: We analysed the clinical data and patch test results obtained with the European baseline series (BSE) and an EOS, as well as the mode of use of EOs, through a questionnaire included in the patient file. RESULTS: The study included 42 patients (79% women, average age 50 years) with allergic contact dermatitis (ACD), 8 patients required hospitalization. All patients were sensitized to the EO they used, primarily lavender (Lavandula augustifolia, 8000-28-0), tea tree (Melaleuca alternifolia leaf oil, 68647-73-4), ravintsara (Cinnamomum camphora oil, 92201-50-8), and 2 cases were attributed to helichrysum (helichrysum italicum flower absolute, 90045-56-0). 71% had positive patch tests to fragrance mix I or II, 9 only to the EOS and 4 only with their personal EO. Interestingly, 40% of patients did not spontaneously mention the use of EOs, and only 33% received advice on their use at the time of purchase. CONCLUSION: Patch tests with the BSE, limonene and linalool HP, and oxidized tea tree oil is sufficient to detect most EO-sensitized patients. The most important is to test the patient's own used EOs.

First report of Trunk Canker Caused by Botryosphaeria dothidea on Cinnamomum camphora in China.

Cinnamomum camphora, an essential woody plant in China, experienced a severe outbreak of trunk canker affecting an area of 540,000 square meters in the Xiaoshan District of Zhejiang province during the early summer of 2022. The observed symptoms included stem canker, dieback, twig blight, and extensive vascular discoloration, with an incidence rate ranging from 45% to 70%. To investigate the etiology of the disease, symptomatic plant samples were subjected to rigorous surface sterilization involving washing with running tap water, followed by surface sterilization using 75% ethanol. The samples were then rinsed twice with sterile distilled water, plated on potato dextrose agar (PDA) medium, and incubated at a temperature of 28°C. The isolated fungi exhibited characteristics consistent with the species Botryosphaeria dothidea. Fungal isolates displayed abundant white aerial mycelium, which darkened to grey after five to seven days, eventually giving rise to black pycnidia. Single hyphal tip cultures of putative two isolates were stored at the Agricultural Experiment Station of Zhejiang University. Conidia formed on pycnidia were one-celled, hyaline, aseptate, and fusiform, with dimensions of 18.34-27.12 µm x 3.77-6.84 µm (average 22.90 µm x 5.20 µm) (one hundred conidia were measured). To determine the fungal species, genomic DNA was extracted from individual isolates ZJUP0868, and subjected to DNA sequence analysis of four gene regions: the internal transcribed spacer (ITS) using the primer-pair ITS4 and ITS1 (White et al., 1990), the large subunit (LSU) gene with LR0R and LR5 (Rehner and Samuels, 1995), the small subunit (SSU) gene with SR1R and SR7 (Zoller et al., 1999), and the translation elongation factor 1-alpha (tef1) with EF1-983F and EF1-2218R (Rehner and Buckley, 2005). Furthermore, DNA sequence analysis of above four genes was performed. BLAST analysis indicated the highest nucleotide sequence identity with Botryosphaeria dothidea CBS 115476 reference sequence (ITS: 99.59%, KF766151; LSU: 99.88%, DQ377852; SSU: 100%, NG_062738; tef1: 98.93%, AY236898). Representative sequences of isolate ZJUP0868 from these regions were deposited in GenBank (ITS: Accession No. OR192838; LSU: Accession No:OR248147; SSU: Accession No:OR248174; tef1: Accession No. OR262053). A phylogenomic analysis was conducted to determine the phylogenetic position of Botryosphaeria dothidea in the family Botryosphaeriaceae. The combined morphological and molecular findings confirmed the identification of the pathogen as Botryosphaeria dothidea. Pathogenicity tests were conducted by stem inoculation of two-year-old Cinnamomum camphora baranches. Mycelial plugs (2-3 mm in diameter) from actively growing colonies of B. dothidea (PDA) were applied to bark of similar size on the middle point of the stems. Inoculated barks were wrapped with Parafilm, while control branches received sterile PDA plugs. Inoculated and control branches (7 each) were maintained in a greenhouse at 28°C. After two weeks, all inoculated plants exhibited dark vascular stem tissue, whereas the control plants remained healthy. B. dothidea was re-isolated from symptomatic tissues, thus fulfilling Koch's postulates. No symptoms were observed in the control branched, and B. dothidea was not re-isolated from their tissues. B. dothidea , the type species of Botryosphaeria (Botryosphaeriaceae, Botryosphaeriales), is commonly associated with cankers and dieback in woody plants. Previous reports have identified Botryosphaeria dothidea as a pathogen causing stem dieback and trunk canker on Glycine max (Chen et al., 2020), Camellia oleifera (Hao et al., 2022), and Gleditsia sinensis (Huang et al., 2020). Additionally, B. dothidea has been reported to cause leave wilt on various plant species in China, including Daimyo oak (Liu et al., 2023) and Cornus officinalis (Zhang et al., 2022). To the best of our knowledge, this is the first report of B. dothidea on C. camphora in China. This findings contribute to a better understanding of the pathogens affecting Cinnamomum camphora in the China.

Linalool Induces Resistance Against Tobacco Mosaic Virus in Tobacco Plants.

The essential oil of Cinnamomum camphora is the most widely consumed and used spice in the world today. It has therapeutic effects in medicine and has been shown to have good antibacterial and bacteriostatic effects in agriculture. This study found that C. camphora oil significantly induced plant disease resistance activity. Linalool, its main active component, significantly induced plant disease resistance activity (67.49% at a concentration of 800 µg/ml) over the same concentration of the chitosan oligosaccharide positive control but had no direct effect on tobacco mosaic virus (TMV). In this study of its antiviral mechanism, linalool induced hypersensitive reaction (HR); the overexpression of related defense enzymes SOD, CAT, POD, and PAL; and the accumulation of H2O2 and SA content in N. glutinosa. Besides, linalool induced crops resistance against Colletotrichum lagenarium, Botrytis cinerea, Sclerotinia sclerotiorum, and Phytophthora capsica. Taken together, the anti-TMV mechanism of linalool involved the induction of plant disease resistance through activation of a plant immune response mediated by salicylic acid. Linalool-induced plant disease resistance activity has a long duration, broad spectrum, and rich resources; linalool thus has the potential to be developed as a new plant-derived antiviral agent and plant immune activator.

Isolation and characterization of gut bacteria associated with the degradation of host-specific terpenoids in Pagiophloeus tsushimanus (Coleoptera: Curculionidae) larvae.

Insect intestinal bacteria play an important role in resisting defensive substances of host plants. Pagiophloeus tsushimanus (Coleoptera: Curculionidae) feeds exclusively on camphor trees (Cinnamomum camphora, Laurales: Lauraceae) in China, causing substantial economic and ecological losses. It is unclear how the larvae of P. tsushimanus outcome the main secondary metabolites of C. camphora such as D-camphor, eucalyptol, and linalool. In this study, we isolated terpenoid-degrading bacteria from the gut of P. tsushimanus larvae by using selective culture medium. Maximum likelihood phylogenetic analyses were performed with 16S rDNA sequences to identify the bacteria, and results showed ten strains belonged to four genera, including Pseudomonas, Enterobacter, Serratia, and Corynebacterium. Then, gas chromatography was employed to determine the degradability of D-camphor, eucalyptol, and linalool by the isolated strains, results showed that Z5 strain (i.e., Corynebacterium variabile, Actinomycetales: Corynebacteriaceae), F1 strain (i.e., Pseudomonas aeruginosa, Pseudomonadales: Pseudomonaceae), and A3 strain (i.e., Serratia marcescens, Enterobacterales: Enterobacteriaceae) had the highest degradation rates of D-camphor, linalool, and eucalyptol, respectively. The intestinal bacteria were capable of terpenoid degradation in vitro, which suggested that these gut bacteria associated with P. tsushimanus play an important role in overcoming host plant secondary metabolite defense, thereby facilitating the host specialization of this pest.

Genome-Wide Characterization and Analysis of bHLH Transcription Factors Related to Anthocyanin Biosynthesis in Cinnamomum camphora ('Gantong 1').

Cinnamomum camphora is one of the most commonly used tree species in landscaping. Improving its ornamental traits, particularly bark and leaf colors, is one of the key breeding goals. The basic helix-loop-helix (bHLH) transcription factors (TFs) are crucial in controlling anthocyanin biosynthesis in many plants. However, their role in C. camphora remains largely unknown. In this study, we identified 150 bHLH TFs (CcbHLHs) using natural mutant C. camphora 'Gantong 1', which has unusual bark and leaf colors. Phylogenetic analysis revealed that 150 CcbHLHs were divided into 26 subfamilies which shared similar gene structures and conserved motifs. According to the protein homology analysis, we identified four candidate CcbHLHs that were highly conserved compared to the TT8 protein in A. thaliana. These TFs are potentially involved in anthocyanin biosynthesis in C. camphora. RNA-seq analysis revealed specific expression patterns of CcbHLHs in different tissue types. Furthermore, we verified expression patterns of seven CcbHLHs (CcbHLH001, CcbHLH015, CcbHLH017, CcbHLH022, CcbHLH101, CcbHLH118, and CcbHLH134) in various tissue types at different growth stages using qRT-PCR. This study opens a new avenue for subsequent research on anthocyanin biosynthesis regulated by CcbHLH TFs in C. camphora.

The Mosquito Larvicidal Activity of Lignans from Branches of Cinnamomum camphora chvar. Borneol.

The chemical investigation of branches of Cinnamomum camphora chvar. Borneol guided by mosquito larvicidal activity led to the isolation of fourteen known lignans (1-14). Their structures were elucidated unambiguously based on comprehensive spectroscopic analysis and comparison with the literature data. This is the first report of these compounds being isolated from branches of Cinnamomum camphora chvar. Borneol. Compounds 3-5 and 8-14 were isolated from this plant for the first time. All compounds isolated were subjected to anti-inflammatory, mosquito larvicidal activity and cytotoxic activity evaluation. Compounds (1-14) showed significant mosquito larvicidal activity against Culex pipiens quinquefasciatus with lethal mortality in 50% (LC50), with values ranging from 0.009 to 0.24 µg/mL. Among them, furofuran lignans(1-8) exhibited potent mosquito larvicidal activity against Cx. p. quinquefasciatus, with LC50 values of 0.009-0.021 µg/mL. From the perspective of a structure-activity relationship, compounds with a dioxolane group showed high mosquito larvicidal activity and have potential to be developed into a mosquitocide.

Chemical Variation and Environmental Influence on Essential Oil of Cinnamomum camphora.

Cinnamomum camphora is a traditional aromatic plant used to produce linalool and borneol flavors in southern China; however, its leaves also contain many other unutilized essential oils. Herein, we report geographic relationships for the yield and compositional diversity of C. camphora essential oils. The essential oils of 974 individual trees from 35 populations in 13 provinces were extracted by hydrodistillation and analyzed qualitatively and quantitatively by gas chromatography-mass spectrometry and gas chromatography-flame ionization detection, respectively. Oil yields ranged from 0.01% to 3.46%, with a significantly positive correlation with latitude and a significantly negative correlation with longitude. In total, 41 compounds were identified, including 15 monoterpenoids, 24 sesquiterpenoids, and two phenylpropanoids. Essential oil compositions varied significantly among individuals and could be categorized into various chemotypes. The six main chemotypes were eucalyptol, nerolidol, camphor, linalool, selina, and mixed types. The other 17 individual plants were chemotypically rare and exhibited high levels of methyl isoeugenol, methyl eugenol, δ-selinene, or borneol. Eucalyptol-type plants had the highest average oil yield of 1.64%, followed in decreasing order by linalool-, camphor-, mixed-, selina-, and nerolidol-type plants. In addition, the five main compounds exhibited a clear geographic gradient. Eucalyptol and linalool showed a significantly positive correlation with latitude, while selina-6-en-4-ol was significantly and negatively correlated with latitude. trans-Nerolidol and selina-6-en-4-ol showed significantly positive correlations with longitude, whereas camphor was significantly and negatively correlated with longitude. Canonical correspondence analysis indicated that environmental factors could strong effect the oil yield and essential oil profile of C. camphora.

[Systematic identification of chemical forms of key terpene synthase in Cinnamomum camphora].

Cinnamomum camphora is an important economic tree species in China. According to the type and content of main components in the volatile oil of leaf, C. camphora were divided into five chemotypes, including borneol-type, camphor-type, linalool-type, cineole-type, and nerolidol-type. Terpene synthase(TPS) is the key enzyme for the formation of these compounds. Although several key enzyme genes have been identified, the biosynthetic pathway of(+)-borneol, which has the most economic value, has not been reported. In this study, nine terpenoid synthase genes CcTPS1-CcTPS9 were cloned through transcriptome analysis of four chemical-type leaves. After the recombinant protein was induced by Escherichia coli, geranyl pyrophosphate(GPP) and farnesyl pyrophosphate(FPP) were used as substrates for enzymatic reaction, respectively. Both CcTPS1 and CcTPS9 could catalyze GPP to produce bornyl pyrophosphate, which could be hydrolyzed by phosphohydrolase to obtain(+)-borneol, and the product of(+)-borneol accounted for 0.4% and 89.3%, respectively. Both CcTPS3 and CcTPS6 could catalyze GPP to generate a single product linalool, and CcTPS6 could also react with FPP to generate nerolidol. CcTPS8 reacted with GPP to produce 1,8-cineol(30.71%). Nine terpene synthases produced 9 monoterpene and 6 sesquiterpenes. The study has identified the key enzyme genes responsible for borneol biosynthesis in C. camphora for the first time, laying a foundation for further elucidating the molecular mechanism of chemical type formation and cultivating new varieties of borneol with high yield by using bioengineering technology.

Antimicrobial and anti-dust mite efficacy of Cinnamomum camphora chvar. Borneol essential oil using pilot-plant neutral cellulase-assisted steam distillation.

Cinnamomum camphora chvar. Borneol essential oil (BEO) was efficiently extracted by using pilot-plant neutral cellulase-assisted steam distillation (NCSD). Borneol, ß-cadinene and α-caryophyllene were identified as major components. Bacillus subtilis was the most sensitive bacteria to BEO with the lowest minimal inhibition concentration (MIC) and minimal bactericial concentration (MBC) at 1·75 and 3·50 mg ml-1 , respectively. Antimicrobial activity of the BEO was also reasonably high against Salmonella typhimurium, Escherichia coli and Staphylococcus aureus, but not sensitive against two fungi, i.e. Aspergillus niger and Penicillium aurantiogriseum. Changes in permeability and integrity of cell membrane, damage of cell wall and further leakage out of metabolites and ions were determined as bactericidal mechanisms of BEO against the two gram-positive bacteria. The BEO showed a reasonably high repelling activity of dust mite, which achieved higher than 95% repelling dust mite activity after the treatment of BEO solution at 0·50 mg ml-1 . When the concentration of BEO was higher than 0·50 mg ml-1 , it was B-grade miticide with miticidal activity higher than 95%. Miticidal procedures were characterized as excitation, contraction, relaxation and lastly leading to the death of dust mite. It is speculated that the BEO would cause dehydration and death of dust mite as neuromuscular toxicity.