PcENO3 interacts with patchoulol synthase to positively affect the enzymatic activity and patchoulol biosynthesis in Pogostemon cablin.

Patchouli alcohol, a significant bioactive component of the herbal plant Pogostemon cablin, has considerable medicinal and commercial potential. Several genes and transcription factors involved in the biosynthesis pathway of patchouli alcohol have been identified. However, so far, regulatory factors directly interacting with patchouli synthase (PTS) have not been reported. This study was conducted to analyze the interaction between PcENO3 and PcPTS to explore the molecular regulation effect of PcENO3 on patchouli alcohol biosynthesis. PcENO3, a homologous protein of Arabidopsis ENO3 belonging to the enolase family, was identified and characterized. Subcellular localization experiments in Arabidopsis protoplast cells indicated that the PcENO3 protein was localized in both the cytoplasm and nucleus. The physical interaction between PcENO3 and PcPTS was confirmed through yeast two-hybrid (Y2H), GST pull-down, and bimolecular fluorescence complementation assays. Furthermore, the Y2H assay demonstrated that PcENO3 could also interact with JAZ proteins in the JA pathway. Enzymatic assays showed that the interaction with PcENO3 increased the catalytic activity of patchoulol synthase. Additionally, suppression of PcENO3 expression with VIGS (virus-induced gene silencing) decreased patchouli alcohol content compared to the control. These findings suggest that PcENO3 interacts with patchoulol synthase and modulates patchoulol biosynthesis by enhancing the enzymatic activity of PcPTS.

Global dissection of R2R3-MYB in Pogostemon cablin uncovers a species-specific R2R3-MYB clade.

MYB family is one of the largest transcription factor families in plants and plays a crucial role in regulating plant biochemical and physiological processes. However, R2R3-MYBs in patchouli have not been systematically investigated. Here, based on the gene annotation of patchouli genome sequence, 484 R2R3-MYB transcripts were detected. Further in-depth analysis of the gene structure and expression of R2R3-MYBs supported the tetraploid hybrid origin of patchouli. When combined with R2R3-MYBs from Arabidopsis, a phylogenetic tree of patchouli R2R3-MYBs was constructed and divided into 31 clades. Interestingly, a patchouli-specific R2R3-MYB clade was found and confirmed by homologous from other Lamiaceae species. The syntenic analysis demonstrated that tandem duplication contributed to its evolution. This study systematically analysed the R2R3-MYB family in patchouli, providing information on its gene characterization, functional prediction, and species evolution.

Characterization of a Cytosolic Acyl-Activating Enzyme Catalyzing the Formation of 4-Methylvaleryl-CoA for Pogostone Biosynthesis in Pogostemon Cablin.

Pogostone, a compound with various pharmaceutical activities, is a major constituent of the essential oil preparation called Pogostemonis Herba, which is obtained from the plant Pogostemon cablin. The biosynthesis of pogostone has not been elucidated, but 4-methylvaleryl-CoA (4MVCoA) is a likely precursor. We analyzed the distribution of pogostone in P. cablin using gas chromatography-mass spectrometry (GC-MS) and found that pogostone accumulates at high levels in the main stems and leaves of young plants. A search for the acyl-activating enzyme (AAE) that catalyzes the formation of 4MVCoA from 4-methylvaleric acid was launched, using an RNAseq-based approach to identify 31 unigenes encoding putative AAEs including the PcAAE2, the transcript profile of which shows a strong positive correlation with the distribution pattern of pogostone. The protein encoded by PcAAE2 was biochemically characterized in vitro and shown to catalyze the formation of 4MVCoA from 4-methylvaleric acid. Phylogenetic analysis showed that PcAAE2 is closely related to other AAE proteins in P. cablin and other species that are localized to the peroxisomes. However, PcAAE2 lacks a peroxisome targeting sequence 1 (PTS1) and is localized in the cytosol.

PatJAZ6 Acts as a Repressor Regulating JA-Induced Biosynthesis of Patchouli Alcohol in Pogostemon Cablin.

The JASMONATE ZIM DOMAIN (JAZ) proteins act as negative regulators in the jasmonic acid (JA) signaling pathways of plants, and these proteins have been reported to play key roles in plant secondary metabolism mediated by JA. In this study, we firstly isolated one JAZ from P. cablin, PatJAZ6, which was characterized and revealed based on multiple alignments and a phylogenic tree analysis. The result of subcellular localization indicated that the PatJAZ6 protein was located in the nucleus of plant protoplasts. The expression level of PatJAZ6 was significantly induced by the methyl jasmonate (MeJA). Furthermore, by means of yeast two-hybrid screening, we identified two transcription factors that interact with the PatJAZ6, the PatMYC2b1 and PatMYC2b2. Virus-induced gene silencing (VIGS) of PatJAZ6 caused a decrease in expression abundance, resulting in a significant increase in the accumulation of patchouli alcohol. Moreover, we overexpressed PatJAZ6 in P. cablin, which down-regulated the patchoulol synthase expression, and then suppressed the biosynthesis of patchouli alcohol. The results demonstrate that PatJAZ6 probably acts as a repressor in the regulation of patchouli alcohol biosynthesis, contributed to a model proposed for the potential JA signaling pathway in P. cablin.

Cablinosides A and B, Two Glycosidic Phenylacetic Acid Derivatives from the Leaves of Pogostemon cablin.

A pair of new glycosidic epimers, cablinosides A (1a) and B (1b) were isolated from the leaves of Pogostemon cablin. The structures with absolute configurations of 1a and 1b were elucidated by extensive NMR investigation, and quantum chemical CD calculations. The epimer mixture 1 showed moderate α-glucosidase inhibitory activity and no significant cytotoxic activity against HepG2 cells.

Comparative proteomic analysis of Pogostemon cablin leaves after continuous cropping.

A proteomic approach was used to understand the molecular mechanisms underlying obstacles to the continuous cropping of Pogostemon cablin. We examined differences in protein abundance between control (CK) and continuously cropped (TR) P. cablin leaves at different time points (90, 150, and 210 days after culture). Comparative analysis by two-dimensional gel electrophoresis (2-DE) and mass spectrometry (MS) revealed 183 differentially expressed protein spots, of which 87 proteins or isoforms were identified using mass spectrometry. Among these differentially expressed proteins (DEPs), 50 proteins or isoforms showed increased abundance and 37 proteins or isoforms showed decreased abundance in the TR sample compared with the abundance in the CK sample. Bioinformatic tools were used to analyze the DEPs. These proteins were classified into 12 categories according to clusters of orthologous groups (COG) analysis, with the majority being involved in post-translational modification, protein turnover, and chaperones, followed by carbohydrate transport and metabolism, and finally, energy production and conversion. Protein-protein interactions revealed that 18 DEPs were involved in energy metabolism, 6 DEPs were involved in stress response, and 4 DEPs were involved in amino acid biosynthesis. Continuous cropping altered the expression of proteins related to energy metabolism, carbohydrate metabolism, and amino acid metabolism in P. cablin leaves. Among these processes, the most affected was energy metabolism, which may be pivotal for resistance to continuous cropping.

Prophylactic efficacy of patchoulene epoxide against ethanol-induced gastric ulcer in rats: Influence on oxidative stress, inflammation and apoptosis.

Patchoulene epoxide (PAO), a tricyclic sesquiterpene isolated from the long-stored patchouli oil, has been demonstrated the anti-inflammatory activity in vivo based on our previous study. However, the gastric protective effect of PAO still remains unknown. Therefore, in the present study, ethanol-induced gastric ulcer model was carried out to evaluate the anti-ulcerogenic activity of PAO and to elucidate the potential mechanisms that involves. According to our results, macroscopic examination revealed that PAO could significantly reduce ethanol-induced gastric ulcer areas as compared with the vehicle group, which was also supported by the histological evaluation result. As for its potential mechanism, the anti-inflammatory activity of PAO contributed to gastric protection through reversing the imbalance between pro- and anti-inflammatory cytokines and modulating the expressions of NF-κB pathway-related proteins including p-IκBα, IκBα, p-p65 and p65. Besides, PAO was able to enhance the expressions of antioxidant enzymes including glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT), and down-regulate malonaldehyde (MDA), an indicator of lipid peroxidation. Furthermore, immunohistochemistry analysis exhibited potent anti-apoptosis effect of PAO, as evidence by down-regulating the protein expression of caspase-3, Fas and Fasl. Additionally, we also demonstrated that PAO could replenish PGE2 and NO mucosal defense. In conclusion, these findings suggested that PAO has gastric protective activity against ethanol and this might be related to its influence on inflammatory response, oxidative stress, apoptosis cascade and gastric mucosal defense.

Aging and/or tissue-specific regulation of patchoulol and pogostone in two Pogostemon cablin (Blanco) Benth. cultivars.

In Pogostemon cablin (Blanco) Benth. essential oil, patchoulol and pogostone are the two major bioactive phytochemicals while their in vivo biosynthesis remains largely unknown. In this study, seven genes of the plastidic methylerythritol 4-phosphate pathway (MEP) and three genes of the cytoplasmic mevalonate pathway (MVA) in two cultivars, HN and YN, were isolated. Gene expression and phytochemical profiles across leaves and stems at different developmental stages of the two cultivars were evaluated using quantitative reverse-transcription polymerase chain reaction and gas chromatography-mass spectrometry, respectively. Hierarchical analysis showed that the expression of MVA- and MEP-related genes was clustered similarly in the two cultivars. Phytochemical assay revealed that the contents of patchoulol in leaves and pogostone in stems were regulated in an aging-dependent manner. Pogostone was only detected in stems but not in leaves of the two cultivars. The Pearson correlation analysis suggested that several genes were presumably involved in the biosynthesis of patchoulol and pogostone. In the YN cultivar, the 1-deoxy-d-xylulose-5-phosphate reductoisomerase and isopentenyl pyrophosphate isomerase 2 genes, and 2-C-methyl-d-erythritol 4-phosphate cytidylyltransferase were positively responsible for patchoulol and pogostone biosynthesis, respectively. In the HN cultivar, 3-hydroxy-3-methylglutaryl-coenzyme A reductase and mevalonate diphosphate decarboxylase, and mevalonate kinase expression were positively associated with pogostone and patchoulol biosynthesis, respectively. The genes identified in this study are good candidates for the enhancement of patchoulol content in the leaves or pogostone content in the stems of P. cablin. Taken together, our results lay a solid foundation for better understanding of the mechanism underlying patchoulol and pogostone biosynthesis, which in turn may help to improve their content in P. cablin.

Survey of the genome of Pogostemon cablin provides insights into its evolutionary history and sesquiterpenoid biosynthesis.

Pogostemon cablin (Blanco) Benth. (Patchouli) is an important traditional Chinese medicinal plant that has both essential oil value and a broad range of therapeutic effects. Here we report the first de novo assembled 1.15-Gb draft genome sequence for P. cablin from next-generation sequencing technology. Our assembly, with a misassembly rate of <4 bp per 100 kb, is ~73% of the predicted genome size (1.57 Gb). Analysis of whole-genome sequences identified 3,147,333 heterozygous single-nucleotide polymorphisms and 490,407 insertions and deletions, giving an estimated heterozygosity rate of 0.274%. A comprehensive annotation pipeline indicated that repetitive sequences make up 58.55% of the assemblies, and that there are estimated 45,020 genes. Comparative genomics analysis showed that the Phrymaceae and Lamiaceae family split ~62.80 Mya, and the divergence between patchouli and sesame occurred ~52.42 Mya, implying a potentially shared recent whole-genome duplication event. Analysis of gene homologs involved in sesquiterpenoid biosynthesis showed that patchouli contains key genes involved in more sesquiterpenoid types and has more copies of genes for each sesquiterpenoid type than several other related plant species. The patchouli genome will facilitate future research on secondary metabolic pathways and their regulation as well as potential selective breeding of patchouli.

Desenvolvimento vegetativo e produção de óleo essencial de patchouli (Pogostemon cablin (Blanco) Benth. ) após a aplicação de ácido giberélico e extrato de alga marinha / Development and essential oil production of Pogostemon cablin (Blanco) Benth. patchouli after applying gibberellic acid and seaweed extract

Pogostemon cablin (Blanco) Benth., comumente conhecido como patchouli, é uma espécie aromática utilizada pela indústria de perfumes devido a fragrância amadeirada e propriedade fixadora do óleo essencial. Fatores que afetam o teor dos constituintes do óleo essencial devem ser avaliados visando obter matéria prima de melhor qualidade. O experimento foi conduzido em casa de vegetação com delineamento inteiramente casualizado em esquema fatorial 2x3 e 4 repetições, sendo dois níveis de giberelina (0 e 200 mg L-1) e três níveis de extrato de alga marinha (0, 15 e 30 mg L-1). A aplicação dos reguladores vegetais foi realizada 30 dias após o plantio das mudas, e a avaliação do experimento deu-se 45 dias após a aplicação dos tratamentos. Não houve diferença significativa para a altura das plantas, a concentração de extrato de alga marinha de 15 mg L-1 promoveu aumento no número de folhas em relação à testemunha e a concentração de 30 mg L-1 promoveu decréscimo. Em relação à área foliar e ao número de folhas houve relação inversa para os níveis de extrato de alga marinha, onde o tratamento com maior concentração do regulador resultou em aumento da área foliar e redução do número de folhas. O teor de óleo essencial foi superior após a aplicação de 15 mg L-1 de extrato alga marinha isoladamente ou combinado com GA3. A produtividade do óleo essencial também aumentou com a aplicação 15 mg L-1 de extrato de alga marinha e quando utilizado somente GA3. A utilização de extrato de alga marinha aumentou a concentração de patchoulol no óleo essencial.

Pogostemon cablin (Blanco) Benth., commonly known as patchouli, is an aromatic species used by the perfume industry due to its woody fragrance and the fixative characteristic of its essential oil. Factors affecting the content of the constituents of essential oils should be evaluated in order to obtain raw materials with better quality. The experiment was carried out in a greenhouse in a completely randomized 2x3 factorial arrangement and four replications, with two levels of gibberellin (0 and 200 mg L-1) and three levels of seaweed extract (0, 15 and 30 mg L-1). Plant regulators were applied thirty days after planting the seedlings; the experiment was evaluated forty-five days after the treatments. There was no significant difference in plant height; the 15 mg L-1 concentration of seaweed extract promoted an increase in the number of leaves in relation to the control; and the 30 mg L-1 concentration promoted a decrease. In relation to leaf area and leaf number, there was an inverse relationship for the seaweed extract levels, in which the treatment with higher a concentration of the regulator resulted in an increased leaf area, reducing the number of leaves. The essential oil content was higher after applying 15 mg L-1 of seaweed extract alone or combined with GA3. The yield of essential oil also increased by applying 15 mg L-1 of seaweed extract and when only GA3 was used. The use of seaweed extract increased the patchoulol concentration in the essential oil.