Chemical Investigation on the Volatile Part of the CO2 Supercritical Fluid Extract of Infected Aquilaria sinensis (Chinese Agarwood).

This work is focused on the characterization of the composition of a CO2 supercritical fluid extract of Aquilaria sinensis (Chinese agarwood) collected in the Dongguan area (China) and infected by mechanical methods. The constituents of this extract were analyzed by gas chromatography-mass spectrometry (GC-MS) and quantified accurately by gas chromatography with a flame ionization detector (GC-FID), using an internal reference and predicted response factors. Since a significant number of components of this extract remained non-identified after the initial GC-MS analysis of the whole extract, its fractionation by chromatography on silica gel helped to characterize several additional constituents by isolation and structural analysis by NMR spectroscopy. The main components are the classical agarwood chromones (Flindersia chromone and its mono-, di-, and trimethoxylated analogues (respectively, 11.01% and 0.11-4.02%) along with sesquiterpenic constituents typically found in agarwood essential oils, like baimuxinal (1.90%) and kusunol (1.24%), as well as less common selinane dialdehydes (1.58-2.27%) recently described in the literature. Moreover, the structure and stereochemistry of a new sesquiterpenic alcohol, 14ß,15ß-dimethyl-7αH-eremophila-9,11-dien-8ß-ol (0.67%), was determined unambiguously by the combination of structural analysis (NMR, MS), hemisynthesis, and total synthesis, leading to dihydrokaranone and a neopetasane epimer.

The chemical profiles and cytotoxicity of gaharu bouya oil from Borneo's Gonystylus bancanus wood.

Gaharu bouya oil obtained from distillation of the woods from Gonystylus genus has attracted essential oil industry interest. However, the information about gaharu bouya essential oil profile is limited. The presence of Gonystylus species is also critically endangered on the IUCN Red List. Therefore, exploring the -omics profiles of Gonystylus bancanus, a native plant from Borneo Island, is important for Indonesia to conserve the population. This research investigated the metabolite profiling of G. bancanus oil, especially the volatile components of its essential oils. Distillations were performed in two technical ways: hydrodistillation on a laboratory scale and steam distillation on an industrial scale. According to LC-MS and GC-MS profiles, both essential oils displayed similar chemical compositions. This article also discusses the similarity of the chemical contents of gaharu bouya oil and agarwood oil from the gaharu superior type (Aquilaria) to support the value of the oil. This research also investigated the cytotoxicity of gaharu bouya oil against three cell lines: HeLa, MCF-7, and HT-29.

Bi-2-(2-phenethyl)chromone derivatives from agarwood of Aquilaria filaria in the Philippines.

Twelve undescribed 2-(2-phenethyl)chromone dimers (1-12) were isolated from EtOAc extract of agarwood originating from Aquilaria filaria in the Philippines, guided by a UHPLC-MS analysis. Their structures were elucidated by 1D NMR, 2D NMR, and HR-ESI-MS spectra. The absolute configuration of 2-(2-phenylethyl)chromone dimers was determined by single-crystal X-ray diffraction analysis and comparison of the experimental and calculated ECD spectra. Compounds 1, 2, 5 and 9-12 exhibited potent to moderate anti-inflammatory activity with IC50 values in the range of 22.43 ± 0.86 to 53.88 ± 4.06 µM.

Optimization of Extraction Process and Analysis of Biological Activity of Flavonoids from Leaves of Cultivated 'Qi-Nan' Agarwood.

Currently, the planting of 'Qi-Nan' is continuously increasing, yet a substantial amount of 'Qi-Nan' leaves have not been properly exploited. To improve the 'Qi-Nan' tree 's utilization value, 'Qi-Nan' leaves were used as a raw material. An ultrasound-assisted method was performed to obtain the flavonoids from the 'Qi-Nan' leaves, followed by optimization of the extraction factors using a one-way and response surface methodology to enhance the extraction of flavonoids. Subsequently, the composition of the flavonoids, as well as their bioactive abilities, were analyzed by ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS) and in vitro activity testing methods. The findings demonstrated that a 1:50 material-to-liquid ratio, 60% ethanol concentration, and ultrasound-assisted extraction time of 30 min were the ideal procedures for extracting flavonoids (flavonoid content: 6.68%). Meanwhile, the 'Qi-Nan' leaves possessed the antioxidant and medicinal potential to prevent diabetes and Alzheimer 's disease, as evidenced by the semi-inhibitory concentrations (IC50 values) of flavonoid extracts for scavenging DPPH• free radicals, scavenging ABTS•+ free radicals, inhibiting acetylcholinesterase, and inhibiting α-glucosidase, which were 12.64 µg/mL, 66.58 µg/mL, 102.31 µg/mL, and 38.76 µg/mL, respectively, which indicated that the 'Qi-Nan' leaves possessed the properties of antioxidant and medicinal potential for the prevention of Alzheimer 's disease and diabetes.

Molecular evolution and characterization of type III polyketide synthase gene family in Aquilaria sinensis.

2-(2-Phenylethyl) chromone (PEC) and its derivatives are markers of agarwood formation and are also related to agarwood quality. However, the biosynthetic and regulatory mechanisms of PECs still remain mysterious. Several studies suggested that type III polyketide synthases (PKSs) contribute to PEC biosynthesis in Aquilaria sinensis. Furthermore, systematic studies on the evolution of PKSs in A. sinensis have rarely been reported. Herein, we comprehensively analyzed PKS genes from 12 plant genomes and characterized the AsPKSs in detail. A unique branch contained only AsPKS members was identified through evolutionary analysis, including AsPKS01 that was previously indicated to participate in PEC biosynthesis. AsPKS07 and AsPKS08, two tandem-duplicated genes of AsPKS01 and lacking orthologous genes in evolutionary models, were selected for their transient expression in the leaves of Nicotiana benthamiana. Subsequently, PECs were detected in the extracts of N. benthamiana leaves, suggesting that AsPKS07 and AsPKS08 promote PEC biosynthesis. The interaction between the promoters of AsPKS07, AsPKS08 and five basic leucine zippers (bZIPs) from the S subfamily indicated that their transcripts could be regulated by these transcription factors (TFs) and might further contribute to PECs biosynthesis in A. sinensis. Our findings provide valuable insights into the molecular evolution of the PKS gene family in A. sinensis and serve as a foundation for advancing PEC production through the bioengineering of gene clusters. Ultimately, this contribution is expected to shed light on the mechanism underlying agarwood formation.

High-throughput sequencing-based analysis of the composition and diversity of the endophyte community in roots of Stellera chamaejasme.

Stellera chamaejasme (S. chamaejasme) is an important medicinal plant with heat-clearing, detoxifying, swelling and anti-inflammatory effects. At the same time, it is also one of the iconic plants of natural grassland degradation in northwest China, playing a key role in the invasion process. Plant endophytes live in healthy plant tissues and can synthesize substances needed for plant growth, induce disease resistance in host plants, and enhance plant resistance to environmental stress. Therefore, studying the root endophytes of S. chamaejasme is of great significance for mining beneficial microbial resources and biological prevention and control of S. chamaejasme. This study used Illumina MiSeq high-throughput sequencing technology to analyze the composition and diversity of endophytes in the roots of S. chamaejasme in different alpine grasslands (BGC, NMC and XGYZ) in Tibet. Research results show that the main phylum of endophytic fungi in the roots of S. chamaejasme in different regions is Ascomycota, and the main phyla of endophytic bacteria are Actinobacteria, Proteobacteria and Firmicutes (Bacteroidota). Overall, the endophyte diversity of the NMC samples was significantly higher than that of the other two sample sites. Principal coordinate analysis (PCoA) and permutational multivariate analysis of variance (PERMANOVA) results showed significant differences in the composition of endophytic bacterial and fungal communities among BGC, NMC and XGYZ samples. Co-occurrence network analysis of endophytes showed that there were positive correlations between fungi and some negative correlations between bacteria, and the co-occurrence network of bacteria was more complex than that of fungi. In short, this study provides a vital reference for further exploring and utilizing the endophyte resources of S. chamaejasme and an in-depth understanding of the ecological functions of S. chamaejasme endophytes.

Salty treatment increased bioactive compounds accumulation during agarwood development in Aquilaria sinensis trees.

To compare the bioactive compounds in agarwood induced by different methods in Aquilaria sinensis(Lour.) Gilg trees, a two dimensional thin layer chromatograph(2D-TLC) combined with effect directive analysis(EDA) was developed. Three antioxidants were found by 2D-TLC-DPPH and further identified as 2-(2-phenylethyl) chromones(PECs) with LC-MS/MS. The 3 antioxidants decreased along agarwood formation and their compositions in drilling induced agarwood differed with those in microbe culture induced agarwood. Further study showed NaCl treatment promoted antioxidants accumulation in agarwood induced by drilling or hot drilling. Hot drilling combined with salty stimulation was most efficient in some chemicals accumulation, which were identified as PECs with antioxidant, tyrosinase or ß-glucosidase inhibiting activities by 2D-TLC-EDA-LC-MS/MS. This study provided a 2D-TLC-EDA-LC-MS/MS method for bioactive compounds screen and qualification of agarwood. Based on this method, non-conventional methods were found to accelerate the accumulation of some bioactive PECs in A. sinensis trees.

Six unprecedented 2-(2-phenethyl)chromone dimers from agarwood of Aquilaria filaria.

Six new dimeric 2-(2-phenylethyl)chromones (1-6) were successfully isolated from the ethanol extract of agarwood of Aquilaria filaria from Philippines under HPLC-MS guidance. Compounds 1-6 are all dimers formed by linking 5,6,7,8-tetrahydro-2-(2-phenylethyl)chromone and flindersia 2-(2-phenylethyl)chromone via a single ether bond, and the linkage site (C5-O-C8'') of compound 2 is extremely rare. A variety of spectroscopic methods were used to ascertain their structures, including extensive 1D and 2D NMR spectroscopic analysis, HRESIMS, and comparison with literature. The in vitro tyrosinase inhibitory and anti-inflammatory activities of each isolate were assessed. Among these compounds, compound 2 had a tyrosinase inhibition effect with an IC50 value of 27.71 ± 2.60 µM, and compound 4 exhibited moderate inhibition of nitric oxide production in lipopolysaccharide-stimulated RAW264.7 cells with an IC50 value of 35.40 ± 1.04 µM.

Edgeworthia gardneri (Wall.) Meisn. Ethanolic Extract Attenuates Endothelial Activation and Alleviates Cardiac Ischemia-Reperfusion Injury.

Endothelial pro-inflammatory activation is pivotal in cardiac ischemia-reperfusion (I/R) injury pathophysiology. The dried flower bud of Edgeworthia gardneri (Wall.) Meisn. (EG) is a commonly utilized traditional Tibetan medicine. However, its role in regulating endothelium activation and cardiac I/R injury has not been investigated. Herein, we showed that the administration of EG ethanolic extract exhibited a potent therapeutic efficacy in ameliorating cardiac endothelial inflammation (p < 0.05) and thereby protecting against myocardial I/R injury in rats (p < 0.001). In line with the in vivo findings, the EG extract suppressed endothelial pro-inflammatory activation in vitro by downregulating the expression of pro-inflammatory mediators (p < 0.05) and diminishing monocytes' firm adhesion to endothelial cells (ECs) (p < 0.01). Mechanistically, we showed that EG extract inhibited the nuclear factor kappa-B (NF-κB), c-Jun N-terminal kinase (JNK), extracellular regulated protein kinase (ERK), and p38 mitogen-activated protein kinase (MAPK) signaling pathways to attenuate EC-mediated inflammation (p < 0.05). Collectively, for the first time, this study demonstrated the therapeutic potential of EG ethanolic extract in alleviating I/R-induced inflammation and the resulting cardiac injury through its inhibitory role in regulating endothelium activation.

Comparative Analysis of Metabolome and Transcriptome in Different Tissue Sites of Aquilaria sinensis (Lour.) Gilg.

The resinous stem of Aquilaria sinensis (Lour.) Gilg is the sole legally authorized source of agarwood in China. However, whether other tissue parts can be potential substitutes for agarwood requires further investigation. In this study, we conducted metabolic analysis and transcriptome sequencing of six distinct tissues (root, stem, leaf, seed, husk, and callus) of A. sinensis to investigate the variations in metabolite distribution characteristics and transcriptome data across different tissues. A total of 331 differential metabolites were identified by chromatography-mass spectrometry (GC-MS), of which 22.96% were terpenoids. The differentially expressed genes (DEGs) in RNA sequencing were enriched in sesquiterpene synthesis via the mevalonate pathway. The present study establishes a solid foundation for exploring potential alternatives to agarwood.

Two new 2-(2-phenylethyl)chromone derivatives and two sesquiterpenes from agarwood of Aquilaria sinensis with anti-inflammatory activity.

Two new 2-(2-phenylethyl)chromones (1-2), two new sesquiterpenes (12-13), and twelve known compounds (3-11, 14-16) were isolated from agarwood of Aquilaria sinensis. These structures were confirmed by HRESIMS, 1D and 2D NMR spectra. The absolute configurations of two new sesquiterpenes were determined by comparing the experimental and calculated ECD spectra. Among them, 7,8-dihydroxy-2-[2-(4'-methoxyphenyl)ethyl]chromone (2) was the first time found that the hydroxyl groups at both C-7/C-8 in agarwood. And Aseudesm B (13), the aldehyded methyl group at C-5 of eucalyptane sesquiterpenes was first discovered in natural products. In the bioassays, all compounds were evaluated for their inhibitory activity against lipopolysaccharide-activated nitric oxide (NO) production in RAW264.7 cells. Compounds 2-5, 7, 9-10, and 13-14 revealed notable inhibitory effects against NO production with IC50 values ranging from 4.0 to 13.0 µM.

Tandem mass spectrometry (MS/MS) molecular networking guided profiling of small molecules from Aquilaria sinensis (Lour.) Gilg leaves and their bioactivity evaluation.

INTRODUCTION: Agarwood, a fragrant resinous wood mainly formed by Aquilaria spp., is used worldwide as a natural fragrance and traditional medicine. A large amount of Aquilaria sinensis (Lour.) Gilg leaves are underutilised during the process of the agarwood industry, and the development of A. sinensis leaves as tea has recently attracted more and more attention. However, the small molecule profile of A. sinensis leaves and their bioactivities has been rarely reported. OBJECTIVE: To conduct a rapid untargeted liquid chromatography-mass spectrometry (LC-MS) analysis of A. sinensis leaves with a molecular networking (MN) strategy and evaluate its antioxidant and antidiabetic value. METHOD: A MN-assisted tandem mass spectrometry (MS/MS) analysis strategy was used to investigate the small molecule profile of A. sinensis leaves. Additionally, the integration of antioxidant and α-glucosidase inhibitory assays with MN analysis was executed to expeditiously characterise the bioactive compounds for potential prospective application. RESULTS: Five main chemical groups including phenol C-glycosides, organic acids, 2-(2-phenylethyl) chromones, benzophenone O-glycosides and flavonoids were rapidly revealed from the A. sinensis leaves. Eighty-one compounds were provisionally identified by comparing their MS/MS fragments with canonical pathways. The featured xanthone C-glycosides and benzophenone C-glycosides were recognised as the primary components of A. sinensis leaves. Several dimers and a trimer of mangiferin were reported firstly in A. sinensis leaves. Furthermore, 17 and 14 potential bioactive molecules were rapidly annotated from antioxidant and α-glucosidase inhibitory fraction, respectively. CONCLUSION: Our findings will help expand the utilisation of A. sinensis leaves and thus promote the high-quality development of agarwood industry.

LC-MS identification, isolation, and structural elucidation of anti-HIV macrocyclic daphnane orthoesters from Edgeworthia chrysantha.

The occurrence of macrocyclic daphnane orthoesters (MDOs) with a 1-alkyl group originating from a C14 aliphatic chain is extremely limited in the plant kingdom and has only been isolated from Edgeworthia chrysantha. In the present study, LC-ESI-MS/MS analysis was performed on different parts of E. chrysantha, including flower buds, flowers, leaves, and stems, and resulted in the identification of seven MDOs in all the four plant parts, including two previously unreported compounds 1 and 7. Further LC-MS guided isolation was carried out to afford compounds 1 and 7, and their structures were determined by various spectroscopic analyses. These compounds were also evaluated for anti-HIV activity, thus expanding insights into the structure-activity relationships for MDOs.

Research progress on the toxicity of toxic Traditional Herbals from Thymelaeaceae.

ETHNOPHARMACOLOGICAL RELEVANCE: Plants from the Thymelaeaceae family are widely distributed in tropical and temperate regions, with approximately 113 species used as Traditional Herbals. There are numerous applications for them, such as treating leukemia, AIDS, and liver cancer. It should be noted that around 20% of these plants have shown harmful side effects when used in clinical applications, including solid irritations to the skin and mucous membranes, carcinogenic effects, organ damage, vomiting, and diarrhea. AIM OF THE STUDY: This paper aims to review the toxic side effects, toxic compounds, toxic mechanisms, and detoxification methods of Traditional Herbals in Thymelaeaceae, guiding their safe clinical uses. MATERIALS AND METHODS: This review employed the keywords "Thymelaeaceae," 48 different "genus," 966 "species," and the combination of "toxicity" to identify the medicinal value and toxicity of plants from Thymelaeaceae in scientific databases (Pubmed, SciFinder Scholar, Elsevier, Web of Science, and CNKI). Information relevant to the toxicity of Traditional Herbals from Thymelaeaceae up to June 2023 has been summarized. The plant names have been checked with "World Flora Online" (www.worldfloraonline.org). RESULTS: 28 toxic Traditional Herbals from 13 genera within the Thymelaeaceae family were categorized. Toxicities were summarized at the cellular, animal, and clinical levels. The toxic substances are primarily concentrated in the Daphne L. and Wikstroemia Endl. genera, with terpenes being the main toxic components. The toxicity mechanism is primarily associated with the mitochondrial pathways. Detoxification and enhanced efficacy can be achieved through processing methods such as vinegar-processing and sweat-soaking. CONCLUSIONS: Medicinal plants in the Thymelaeaceae exhibit significant pharmacological activities, such as anti-HIV and anti-tumor effects, indicating a broad potential for application. However, their clinical uses are hindered by their inherent toxicity. Researching the toxic components and mechanisms of these Traditional Herbals and exploring more effective detoxification methods can contribute to unveiling the latent value of these medicinal plants from Thymelaeaceae.

Terpenoids from the Roots of Stellera chamaejasme (L.) and Their Bioactivities.

An undescribed diterpene, stellerterpenoid A (1), and two undescribed sesquiterpenoids, stellerterpenoids B and C (2-3), together with six known compounds, prostratin (4) stelleraguaianone B (5), chamaejasnoid A (6), auranticanol L (7), wikstronone C (8), and oleodaphnone (9), were isolated from the roots of Stellera chamaejasme L. Their structures were elucidated by extensive spectroscopic data (1D, 2D NMR, IR, UV, and HR-ESI-MS). The absolute configuration of 1-3 was elucidated based on ECD calculation. Among them, stellerterpenoid A was a rare 13, 14-seco nortigliane diterpenoid and stellerterpenoid B was a guaiacane-type sesquiterpenoid with an unusual 1, 2-diketone moiety. The known stelleraguaianone B (5) exhibited moderate activity for suppressing NO production in lipopolysaccharide (LPS)-treated RAW 264.7 macrophages cells with an IC50 value of 24.76 ± 0.4 µM. None of the compounds showed anti-influenza virus or anti-tumor activity in vitro.

[Characterization and phylogenetic analysis of complete chloroplast genome of cultivated Qinan agarwood].

"Tangjie" leaves of cultivated Qinan agarwood were used to obtain the complete chloroplast genome using high-throughput sequencing technology. Combined with 12 chloroplast genomes of Aquilaria species downloaded from NCBI, bioinformatics method was employed to determine the chloroplast genome characteristics and phylogenetic relationships. The results showed that the chloroplast genome sequence length of cultivated Qinan agarwood "Tangjie" leaves was 174 909 bp with a GC content of 36.7%. A total of 136 genes were annotated, including 90 protein-coding genes, 38 tRNA genes, and 8 rRNA genes. Sequence repeat analysis detected 80 simple sequence repeats(SSRs) and 124 long sequence repeats, with most SSRs composed of A and T bases. Codon preference analysis revealed that AUU was the most frequently used codon, and codons with A and U endings were preferred. Comparative analysis of Aquilaria chloroplast genomes showed relative conservation of the IR region boundaries and identified five highly variable regions: trnD-trnY, trnT-trnL, trnF-ndhJ, petA-cemA, and rpl32, which could serve as potential DNA barcodes specific to the Aquilaria genus. Selection pressure analysis indicated positive selection in the rbcL, rps11, and rpl32 genes. Phylogenetic analysis revealed that cultivated Qinan agarwood "Tangjie" and Aquilaria agallocha clustered together(100% support), supporting the Chinese origin of Qinan agarwood from Aquilaria agallocha. The chloroplast genome data obtained in this study provide a foundation for studying the genetic diversity of cultivated Qinan agarwood and molecular identification of the Aquilaria genus.

Comprehensive Analysis of NAC Transcription Factors Reveals Their Evolution in Malvales and Functional Characterization of AsNAC019 and AsNAC098 in Aquilaria sinensis.

NAC is a class of plant-specific transcription factors that are widely involved in the growth, development and (a)biotic stress response of plants. However, their molecular evolution has not been extensively studied in Malvales, especially in Aquilaria sinensis, a commercial and horticultural crop that produces an aromatic resin named agarwood. In this study, 1502 members of the NAC gene family were identified from the genomes of nine species from Malvales and three model plants. The macroevolutionary analysis revealed that whole genome duplication (WGD) and dispersed duplication (DSD) have shaped the current architectural structure of NAC gene families in Malvales plants. Then, 111 NAC genes were systemically characterized in A. sinensis. The phylogenetic analysis suggests that NAC genes in A. sinensis can be classified into 16 known clusters and four new subfamilies, with each subfamily presenting similar gene structures and conserved motifs. RNA-seq analysis showed that AsNACs presents a broad transcriptional response to the agarwood inducer. The expression patterns of 15 AsNACs in A. sinensis after injury treatment indicated that AsNAC019 and AsNAC098 were positively correlated with the expression patterns of four polyketide synthase (PKS) genes. Additionally, AsNAC019 and AsNAC098 were also found to bind with the AsPKS07 promoter and activate its transcription. This comprehensive analysis provides valuable insights into the molecular evolution of the NAC gene family in Malvales plants and highlights the potential mechanisms of AsNACs for regulating secondary metabolite biosynthesis in A. sinensis, especially for the biosynthesis of 2-(2-phenyl) chromones in agarwood.

Characterization of the Microbial Community Structures, Soil Chemical Properties, and Enzyme Activity of Stellera chamaejasme (Thymelaeaceae) and Its Associated Forages in Alpine Grassland of Northwestern China.

The invasion of toxic weeds was detrimental to the growth of original vegetation and speed up the degraded grasslands. The purpose of this study was to explore the difference in microbial community, soil physicochemical properties, and enzyme activity in the rhizosphere of Stellera chamaejasme and its associated forages (Stipa purpurea and Polygonum viviparum). The rhizosphere soil microbial communities of S. chamaejasme and its associated forages were determined by high-throughput sequencing technology, the physicochemical properties, and enzyme activities were also measured using soil chemical methods. We performed biological statistical analyses to explore the correlation of rhizosphere micro-ecological environment between the invading poisonous herb S. chamaejasme and its associated forages. The Ascomycota community in the rhizosphere soil of S. chamaejasme was significantly decreased when compared with its associated forages. S. chamaejasme and S. purpurea had a similar bacterial composition, while the rhizosphere of P. viviparum was associated with more Acidobacteria and Bacteroidetes. The RDA analysis showed S. chamaejasme had highly correlated with acid proteinase, invertase, polyphenol oxidase, cellulose, and neutral protease and S. purpurea had highly associated with N-acetyl-beta-D-glucosaminidase, ß-D-Glucosidase, and the P. viviparum had highly associated with total phosphorus, total nitrogen, ammonium nitrogen, soil organic matter, pH, acid phosphatase, and catalase. Along with the invasion of S. chamaejasme, the microbial composition, soil physicochemical properties, and enzyme activity of the growing area changed considerably compared with the associated forages. Taken together, our results suggested that the composition and diversity of microbial communities associated with S. chamaejasme and its associated forages exhibited different patterns, and the rhizosphere soil microbial communities in different plants were regulated by different environmental factors in this alpine grassland ecosystem.

Integrated transcriptome and metabolome analysis unveils the mechanism of color-transition in Edgeworthia chrysantha tepals.

BACKGROUND: Edgeworthia chrysantha, a deciduous shrub endemic to China, is known for its high ornamental value, extensive cultivation history, and wide-ranging applications. However, theoretical research on this plant is severely lacking. While its flowering process displays striking color transitions from green (S1) to yellow (S2) and then to white (S3), the scientific exploration of this phenomenon is limited, and the underlying regulatory mechanisms are yet to be elucidated. RESULTS: Correlation analysis between phenotypic measurements and pigment content revealed that carotenoids and chlorophyll are the key pigments responsible for the color changes. Metabolomic analysis of carotenoids demonstrated that lutein and ß-carotene were present at higher levels in S1, while S2 exhibited increased diversity and quantity of carotenoids compared to other stages. Notably, antheraxanthin, zeaxanthin, lycopene, and α-cryptoxanthin showed significant increases. In S3, apart from the colorless phytoene, other carotenoid metabolites were significantly reduced to extremely low levels. Transcriptomic data indicated that PSY, Z-ISO, crtZ, ZEP, PDS and ZDS are key genes involved in carotenoid biosynthesis and accumulation, while NCED plays a crucial role in carotenoid degradation. SGR was identified as a key gene contributing to the progressive decline in chlorophyll content. Additionally, three transcription factors potentially regulating carotenoid metabolism were also identified. CONCLUSIONS: This study represents the first systematic investigation, spanning from phenotypic to molecular levels, of the color-changing phenomenon in E. chrysantha. The study elucidates the crucial pigments, metabolites, genes, and transcription factors responsible for flower color changes during the flowering process, thereby providing preliminary understanding of the intrinsic regulatory mechanisms. These findings establish a theoretical foundation for the genetic improvement of flower color in E. chrysantha.

Exploration of the B3 transcription factor superfamily in Aquilaria sinensis reveal their involvement in seed recalcitrance and agarwood formation.

The endangered tree species of the Aquilaria genus produce agarwood, a high value material produced only after wounding; however, conservation of Aquilaria seeds is difficult. The B3 transcription factor family has diverse important functions in plant development, especially in seed development, although their functions in other areas, such as stress responses, remain to be revealed. Here germination tests proved that the seeds of A. sinensis were recalcitrant seeds. To provide insights into the B3 superfamily, the members were identified and characterized by bioinformatic approaches and classified by phylogenetic analysis and domain structure. In total, 71 members were identified and classified into four subfamilies. Each subfamily not only had similar domains, but also had conserved motifs in their B3 domains. For the seed-related LAV subfamily, the B3 domain of AsLAV3 was identical to that of AsVALs but lacked a typical zf-CW domain such as VALs. AsLAV5 lacks a typical PHD-L domain present in Arabidopsis VALs. qRT-PCR expression analysis showed that the LEC2 ortholog AsLAV4 was not expressed in seeds. RAVs and REMs induced after wound treatment were also identified. These findings provide insights into the functions of B3 genes and seed recalcitrance of A. sinensis and indicate the role of B3 genes in wound response and agarwood formation.This is the first work to investigate the B3 family in A. sinensis and to provide insights of the molecular mechanism of seed recalcitrance.This will be a valuable guidance for studies of B3 genes in stress responses, secondary metabolite biosynthesis, and seed development.