Aquilaria Trees Research Articles

3D documentation and classification of incense tree Aquilaria sinensis (Lour.) Spreng. wounds by photogrammetry and its potential conservation applications.

In recent years, illegal felling of and damage to the incense tree Aquilaria sinensis (Lour.) Spreng. have been reported in Hong Kong. Their native populations are under increasingly severe threat. Therefore, the development of a standard and efficient method to classify and document wounds on vulnerable trees is urgently needed for conservation purposes. In this study, photogrammetry was used to document wounds in A. sinensis through 3D modeling. A total of 752 wound records from 484 individual A. sinensis trees from Hong Kong were included to establish a new wound classification system. Our major findings include a novel standardized procedure for photogrammetric documentation and a wound classification system. The results of this study will facilitate A. sinensis conservation, by enhancing wound documentation and information transfer to law enforcement and education.

Determination of Antitumor Active Ingredients in Agarwood Essential Oil by Gas Chromatography-Mass Spectrometry (GC-MS) and Grey Relational Analysis

Agarwood essential oil (AEO) holds significant medicinal and economic value. While its antitumor activity is reported in the literature, the active ingredients remain unexplored. In this study, the chemical composition of AEO extracted by steam distillation (SD) and fungal fermentation-assisted SD (FFSD) was evaluated by gas chromatography-mass spectrometry (GC-MS). The antitumor activity was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Subsequently, the key active ingredients and targets of antitumor activity were evaluated using grey relational analysis and network pharmacology. The relative content of active ingredients in the AEOs extracted from different Aquilaria trees was compared. GC-MS tentatively identified 32 compounds, primarily sesquiterpenoids and aromatic compounds. Eight components with relative content differences were screened using orthogonal partial least squares-discriminant analysis (OPLS-DA), indicating that α-costal, guaiol, β-santalol may play important roles in the antitumor activity. Both SD and FFSD-extracted AEOs demonstrated the ability to inhibit the proliferation and survival of four cancer cell lines, with slightly stronger inhibitory effects observed in AEO extracted by SD. α-Costal, aristolone, 10-epi-γ-eudesmol, γ-eudesmol, agarospirol, hinesol, guaiol, β-santalol, and 6-isopropenyl-4,8a-dimethyl-1,2,3,5,6,7,8,8a-octahydro-naphthalen-2-ol were antitumor ingredients of AEO. The relative content of total active ingredients in agarwood (Aquilaria malaccensis) essential oil was higher, suggesting higher efficacy. This study confirmed the antitumor activity of AEO and identified its active ingredients. These findings provide a basis for further research on the antitumor mechanism of AEO.

Genome-wide analysis of respiratory burst oxidase homolog (Rboh) genes in Aquilaria species and insight into ROS-mediated metabolites biosynthesis and resin deposition.

Respiratory burst oxidase homolog (Rboh) generates reactive oxygen species (ROS) as a defense response during biotic and abiotic stress. In Aquilaria plants, wounding and fungal infection result in biosynthesis and deposition of secondary metabolites as defense responses, which later form constituents of fragrant resinous agarwood. During injury and fungal invasion, Aquilaria tree generates ROS species via the Rboh enzymes. Despite the implication of Rboh genes in agarwood formation, no comprehensive genomic-level study of the Rboh gene family in Aquilaria is present. A systematic illustration of their role during stress and involvement in initiating signal cascades for agarwood metabolite biosynthesis is missing. In this study, 14 Rboh genes were retrieved from genomes of two Aquilaria species, A. agallocha and A. sinensis, and were classified into five groups. The promoter regions of the genes had abundant of stress-responsive elements. Protein-protein network and in silico expression analysis suggested their functional association with MAPK proteins and transcription factors such as WRKY and MYC2. The study further explored the expression profiles of Rboh genes and found them to be differentially regulated in stress-induced callus and stem tissue, suggesting their involvement in ROS generation during stress in Aquilaria. Overall, the study provides in-depth insight into two Rboh genes, AaRbohC and AaRbohA, highlighting their role in defense against fungal and abiotic stress, and likely during initiation of agarwood formation through modulation of genes involved in secondary metabolites biosynthesis. The findings presented here offer valuable information about Rboh family members, which can be leveraged for further investigations into ROS-mediated regulation of agarwood formation in Aquilaria species.

Effects of Different Levels of Physical Damage Combined with Fungal Induction on Agarwood Formation

As wild Aquilaria sinensis resources are exhausted and protected, China has established a huge number of plantations of Aquilaria trees and developed artificial induction techniques. However, the current output and quality of artificial induction technology have not yet met the expected results. It has been found that high-oil-containing agarwood may contain particular fungal stains associated with agarwood production. To enhance the quality of agarwood, we recovered and characterized three highly active fungi from high-oil-containing agarwood and inoculated them onto A. sinensis trees using two traditional physical methods. The results showed that fungi extracted from high-oil-containing agarwood can effectively increase the yield and quality of agarwood. During the agarwood formation process, parenchyma cells, xylem rays, and axial parenchyma cells in the xylem gradually undergo apoptosis, thereby promoting the expansion of the color range of agarwood. Nine months after the treatment, the alcohol-soluble extract content in agarwood reached the standard specified in the Chinese Pharmacopoeia (10%), and the proportions of sesquiterpenes and chromones in each treatment were 55.82%, 58.31%, 62.65%, 70.97%, and 13.71%, respectively. These results indicate that fungal induction has a positive impact on the quality of agarwood. In addition, compared to drilling and fungus combined induction, “burning holes and fungi” combined induction demonstrates better results and can further improve the yield and quality of agarwood.

Physiological and Endophytic Fungi Changes in Grafting Seedlings of Qi-Nan Clones (Aquilaria sinensis)

In recent years, some new Qi-Nan clones of Aquilaria sinensis, which have the characteristics of easily induced and high-quality agarwood, have been selected and propagated by grafting seedlings. To date, research on the grafting of Qi-Nan seedlings is limited. In this study, the effects of grafting on physiological characteristics and endophytic fungi of seedlings within a short period after grafting were studied by means of histochemical observations, physiological index determinations and Illumina sequencing. The results showed that the grafting healing time of ordinary A. sinensis was at least 10 days shorter than that of Qi-Nan, according to the degree of lignification of callus, and the tissue basis for the healing was the interxylary phloem. The MDA content of Qi-Nan peaked earlier than that of ordinary A. sinensis. The contents of JA and ABA peaked earlier in ordinary A. sinensis, and the SA content was significantly higher than that of Qi-Nan at 20–40 days; on average, it was 17.33% higher than that of Qi-Nan. A total of 5 phyla, 28 classes, 84 orders, 197 families, 489 genera and 842 species of endophytic fungi were identified before and after grafting. After grafting, the abundance and diversity of endophytic fungi in ordinary A. sinensis and Qi-Nan decreased, and the endophytic fungi were significantly different before and after grafting. In ordinary A. sinensis, before grafting, Dothideomycetes was the dominant class, and after grafting, Sordariomycetes was the dominant class. The dominant class of Qi-Nan before and after grafting was Dothideomycetes. The dominant genus of ordinary A. sinensis before grafting was Devriesia, and after grafting, it was Fusarium; that of Qi-Nan before grafting was Hyweljonesia and after grafting was Arthopyrenia. Functional genes of the endophytic fungi were mostly related to carbohydrate metabolism and energy metabolism, which may be the reason why endophytic fungi promote agarwood formation in Aquilaria trees. The findings suggest that the healing of the grafting interface in A. sinensis seedlings was the result of multiple factors, and endophytic fungi of Qi-Nan scion changed after grafting.

Barrier zone formation and development in the stems of Aquilaria sinensis (Thymelaeaceae) and the effect on agarwood formation

Summary Barrier and reaction zones are core parts of compartmentalization in trees. However, little is known about the relationship between them. Here, agarwood and barrier zone formation in Aquilaria sinensis trees were studied for the first time using compartmentalization theory. The main results were as follows: (1) Wounding methods had a very important influence on the occurrence of barrier zones in A. sinensis. (2) The barrier zone development process was divided into three phases based on the morphological features. (3) The agarwood resin mainly accreted during the barrier zone lag and division phases; then, after the barrier zone entered the differentiation phase, the resin no longer accreted and even tended to degrade. (4) In the application of the whole-tree agarwood-inducing technique, the barrier zone generally began to appear 10 months after the technique treatment, and the barrier zones were more severe in the lower part of the stem. (5) Considering the agarwood yield, agarwood resin filling degree and ethanol-soluble extract content, the serious barrier zone indeed reduced the agarwood productivity. This study is important for revealing the agarwood and barrier zone formation mechanism in Aquilaria trees. It also provides a good research model for considering the high economic value of agarwood when studying compartmentalization.

Agarwood oil nanoemulsion counteracts LPS-induced inflammation and oxidative stress in RAW264.7 mouse macrophages

PurposeOxidative stress and inflammation are key pathophysiological features of chronic respiratory diseases, including asthma and chronic obstructive pulmonary disease (COPD). Agarwood oil obtained from Aquilaria trees has promising antioxidant and anti-inflammatory activities. However, its clinical application is hampered by poor solubility. A viable approach to overcome this involves formulation of oily constituents into emulsions. Here, we have investigated the antioxidant and anti-inflammatory potential of an agarwood oil-based nanoemulsion (DE’RAAQSIN) against lipopolysaccharide (LPS)-induced RAW264.7 mouse macrophages in vitro. MethodsThe antioxidant and anti-inflammatory activity of DE’RAAQSIN was assessed by measuring the levels of ROS and nitric oxide (NO) produced, using the DCF-DA assay and the Griess reagent assay, respectively. The molecular pathways activated by DE’RAAQSIN were investigated via qPCR. ResultsLPS stimulation of RAW264.7 cells increased the production of nitric oxide (NO) and ROS and resulted in the overexpression of the inducible nitric oxide synthase (iNOS) gene. Furthermore, LPS induced the upregulation of the expression of key proinflammatory genes (IL-6, TNF-α, IL-1β, and CXCL1) and of the antioxidant gene heme oxygenase-1 (HO-1). DE’RAAQSIN demonstrated potent antioxidant and anti-inflammatory activity by significantly reducing the levels of ROS and of secreted NO, simultaneously counteracting the LPS-induced overexpression of iNOS, IL-6, TNF-α, IL-1β, and HO-1. These findings were corroborated by in silico activity prediction and physicochemical analysis of the main agarwood oil components. ConclusionsWe propose DE’RAAQSIN as a promising alternative managing inflammatory disorders, opening the platform for further studies aimed at understanding the effectiveness of DE’RAAQSIN.

Endophyte fungi from Agarwood and Mangrove and their applications

Mangroves are woody trees or shrubs salt marsh halophytes that encompass over 75% of the tropical coastline on the planet. Mangroves are characterized by their sophisticated morphological and physiological adaptations as well as their rich synthesis of biologically active secondary metabolites. They also contribute in decreasing CO2 levels in the atmosphere through photosynthesis. On the other hand, agarwood, is an aromatic perfumed precious heartwood of diseased timber of Aquilaria and Gyrinops trees that is used centuries ago till now as incense in religious ceremonies, raw material in the perfume industry and as a medicine. Agarwood formation is usually induced by wounding trunks and branches of Aquilaria trees. Production of natural agarwood resin is inefficient and don’t meet global demand, so different methods have been applied to stimulate biological agarwood induction, and using endophytic fungi is one of the methods. Hence, this review highlights the importance of endophytic fungi in mangroves and agarwood, their existence and some of their important biological activities.

First Report of Infestation of the Agar Defoliator <i>Heortia vitessoides</i> (Moore) on the Agar Wood Tree <i>Aquilaria malaccensis</i> Benth. in South India

Massive infestation of the agar defoliator Heortia vitessoides (Moore) (Lepidoptera, Pyraloidea, Crambidae) was observed in Thiruvananthapuram and Kollam districts in Kerala on agar wood tree Aquilaria malaccensis Benth. (Thymelaeaceae), during February – December, 2022. Of the 119 trees observed in Thiruvananthapuram and Kollam districts, 115 were infested and six of them died due to the pest attack.

Systematic evolution of bZIP transcription factors in Malvales and functional exploration of AsbZIP14 and AsbZIP41 in Aquilaria sinensis.

Agarwood, the dark-brown resin produced by Aquilaria trees, has been widely used as incense, spice, perfume or traditional medicine and 2-(2-phenethyl) chromones (PECs) are the key markers responsible for agarwood formation. But the biosynthesis and regulatory mechanism of PECs were still not illuminated. The transcription factor of basic leucine zipper (bZIP) presented the pivotal regulatory roles in various secondary metabolites biosynthesis in plants, which might also contribute to regulate PECs biosynthesis. However, molecular evolution and function of bZIP are rarely reported in Malvales plants, especially in Aquilaria trees. Here, 1,150 bZIPs were comprehensively identified from twelve Malvales and model species genomes and the evolutionary process were subsequently analyzed. Duplication types and collinearity indicated that bZIP is an ancient or conserved TF family and recent whole genome duplication drove its evolution. Interesting is that fewer bZIPs in A. sinensis than that species also experienced two genome duplication events in Malvales. 62 AsbZIPs were divided into 13 subfamilies and gene structures, conservative domains, motifs, cis-elements, and nearby genes of AsbZIPs were further characterized. Seven AsbZIPs in subfamily D were significantly regulated by ethylene and agarwood inducer. As the typical representation of subfamily D, AsbZIP14 and AsbZIP41 were localized in nuclear and potentially regulated PECs biosynthesis by activating or suppressing type III polyketide synthases (PKSs) genes expression via interaction with the AsPKS promoters. Our results provide a basis for molecular evolution of bZIP gene family in Malvales and facilitate the understanding the potential functions of AsbZIP in regulating 2-(2-phenethyl) chromone biosynthesis and agarwood formation.

Population genomic analyses of protected incense trees Aquilaria sinensis reveal the existence of genetically distinct subpopulations

The incense tree Aquilaria sinensis (Thymelaeaceae) can produce agarwood with commercial values and is now under threat from illegal exploitation in Hong Kong, impairing the local population and biodiversity. Together with other species of Aquilaria, it is listed in the CITES Appendix II, which strictly regulates its international trade. To understand the population structure of A. sinensis and to make relevant conservation measures, we have sequenced 346 individuals collected in Hong Kong and southern mainland China. Population genomic analyses including principal component analysis, neighbor-joining tree construction, ADMIXTURE, and hierarchical pairwise-FST analyses suggested that genetically distinct populations are contained in certain areas. Genomic scan analyses further detected single-nucleotide polymorphism (SNP) outliers related to plant defense, including the CYP71BE gene cluster. In addition to the population analyses, we have developed a modified hexadecyltrimethyl-ammonium bromide (CTAB) DNA extraction protocol for obtaining DNA from agarwood samples in this study, and resequencing of DNA extracted from two agarwood samples using this method allows us to successfully map to the sample corresponding localities in the phylogenetic tree. To sum up, this study suggested that there is a genetically distinct subpopulation of incense tree in Hong Kong that would require special conservation measures and established a foundation for future conservation measures.

Genome-wide investigation of Cytochrome P450 superfamily of Aquilaria agallocha: Association with terpenoids and phenylpropanoids biosynthesis

Agarwood is a dark resinous wood, produced when Aquilaria tree responds to wounding and microbial infection resulting in the accumulation of fragrant metabolites. Sesquiterpenoids and 2-(2-phenylethyl) chromones are the major phytochemicals in agarwood and Cytochrome P450s (CYPs) are one of the important enzymes in the biosynthesis of these fragrant chemicals. Thus, understanding the repertoire of CYP superfamily in Aquilaria can not only give insights into the fundamentals of agarwood formation, but can also provide a tool for the overproduction of the aroma chemicals. Therefore, current study was designed to investigate CYPs of an agarwood producing plant, Aquilaria agallocha. We identified 136 CYP genes from A. agallocha genome (AaCYPs) and classified them into 8 clans and 38 families. The promoter regions had stress and hormone-related cis-regulatory elements which indicate their participation in the stress response. Duplication and synteny analysis revealed segmental and tandem duplicated and evolutionary related CYP members in other plants. Potential members involved in the biosynthesis of sesquiterpenoids and phenylpropanoids were identified and found to be upregulated in methyl jasmonate-induced callus and infected Aquilaria trees by real-time quantitative PCR analyses. This study highlights the possible involvement of AaCYPs in agarwood resin development and their complex regulation during stress exposure.

RNA-Sequencing Reveals the Involvement of Sesquiterpene Biosynthesis Genes and Transcription Factors during an Early Response to Mechanical Wounding of Aquilaria sinensis.

Plants respond to wounding by reprogramming the expression of genes involved in secondary metabolism. Aquilaria trees produce many bioactive secondary metabolites in response to wounding, but the regulatory mechanism of agarwood formation in the early response to mechanical wounding has remained unclear. To gain insights into the process of transcriptome changes and to determine the regulatory networks of Aquilaria sinensis to an early response (15 days) to mechanical wounding, we collected A. sinensis samples from the untreated (Asc1) and treated (Asf1) xylem tissues and performed RNA sequencing (RNA-seq). This generated 49,102,523 (Asc1) and 45,180,981 (Asf1) clean reads, which corresponded to 18,927 (Asc1) and 19,258 (Asf1) genes, respectively. A total of 1596 differentially expressed genes (DEGs) were detected in Asf1 vs. Asc1 (|log2 (fold change)| ≥ 1, Padj ≤ 0.05), of which 1088 were up-regulated and 508 genes were down-regulated. GO and KEGG enrichment analysis of DEGs showed that flavonoid biosynthesis, phenylpropanoid biosynthesis, and sesquiterpenoid and triterpenoid biosynthesis pathways might play important roles in wound-induced agarwood formation. Based on the transcription factor (TF)-gene regulatory network analysis, we inferred that the bHLH TF family could regulate all DEGs encoding for farnesyl diphosphate synthase, sesquiterpene synthase, and 1-deoxy-D-xylulose-5-phosphate synthase (DXS), which contribute to the biosynthesis and accumulation of agarwood sesquiterpenes. This study provides insight into the molecular mechanism regulating agarwood formation in A. sinensis, and will be helpful in selecting candidate genes for improving the yield and quality of agarwood.

Temporal characteristics of agarwood formation in Aquilaria sinensis after applying whole-tree agarwood-inducing technique

ObjectiveAgarwood—a resinous wood produced by Aquilaria plants in response to injury or artificial induction—is a valuable medicinal and fragrance resource. Whole-Tree Agarwood-Inducing Technique (Agar-WIT) has been widely used to produce agarwood. However, the time-dependent characteristics of agarwood formation induced by Agar-WIT are yet to be clarified. To promote technologically efficient utilization and upgradation of Agar-WIT, the dynamic process and mechanism of agarwood formation were analyzed for one year. MethodsAgarwood formation percentage, barrier layer microscopic properties, extract levels, compound level, and characteristic chromatograms of agarwood were examined by referring to the Chinese Pharmacopeia (2020 version). ResultsAgar-WIT could maintain a high percentage of agarwood formation over one year compared with that of healthy plants. Alcohol-soluble extract and agarotetrol levels showed fluctuating cyclic changes with peaks occurring first during the fifth and sixth months, and subsequently in the 11th month. Aquilaria trees subjected to Agar-WIT treatment for 1–12 months showed significant characteristics of a dynamic agarwood formation process. The barrier layer began to appear in the fourth month after treatment. Alcohol-soluble extractive levels in agarwood formed in the second month, and thereafter, exceeded 10.0%, and agarotetrol in agarwood produced after four months or later, exceeded 0.10%. ConclusionAccording to the Chinese Pharmacopoeia, alcohol-soluble extractive levels in agarwood should not be less than 10.0% and agarotetrol level should exceed 0.10%. After four months of Agar-WIT treatment, the formed agarwood theoretically met these standards and was suitable for developed and utilization. However, the optimal harvest time was found to be the 11th month, followed by the sixth month after Agar-WIT treatment. Therefore, Agar-WIT resulted in swift agarwood formation and stable accumulation of alcohol-soluble extracts and agarotetrol. Thus, this method is efficient for large-scale cultivation of Aquilaria sinensis to produce agarwood and provide raw materials for the agarwood medicinal industry.

Assessment of the Effects of Artificial Fungi Inoculations on Agarwood Formation and Sap Flow Rate of Aquilaria malaccensis Lam. Using Sonic Tomography (SoT) and Sap Flow Meter (SFM)

Agarwood is a valuable aromatic resinous wood that is biosynthesised when a fungal attack injures the healthy wood tissue of the Aquilaria tree. The magnitude of infection related to sap flow (SF) is one of the most critical functional traits to evaluate the tree’s response to various adverse conditions. Therefore, the objective of this study was to investigate the reliability of sonic tomography (SoT) and sap flow meter (SFM) in studying the influence of inoculation fungi Pichia kudriavzevii Boidin, Pignal and Besson, and Paecilomyces niveus Stolk and Samson, on deteriorated wood (Dt) and SF rate in Aquilaria malaccensis Lam. A. malaccensis trees with small, medium, and large diameters were inoculated with each fungus separately at the bottom, middle, and top positions of the tree and the area of sapwood was measured after 6, 12, and 24 months to stimulate the agarwood formation. Furthermore, the SF rate was assessed using SFM in the position of the selected trees. There was a significant difference (p ≤ 0.05) in Dt% and SF rate between inoculated and uninoculated trees. The Dt percentage in trees inoculated with P. kudriavzevii, P. niveus, and control trees was 25.6%, 25.7%, and 15.0%, respectively. The SF rate was lower in P. kudriavzevii, with 207.7 cm3/h, than in the control trees, with 312.9 cm3/h in the small-diameter class. In summary, the results of this study emphasise the importance of inoculation duration (24 months) and the effects of water conductivity, especially tree diameter class (small), on the biosynthetic response of resinous substance.

Genome-wide investigation and expression analysis of the AP2/ERF family for selection of agarwood-related genes in Aquilaria sinensis (Lour.) Gilg.

Aquilaria sinensis is an important non-timber tree species for producing high-value agarwood, which is widely used as a traditional medicine and incense. Agarwood is the product of Aquilaria trees in response to injury and fungal infection. The APETALA2/ethylene responsive factor (AP2/ERF) transcription factors (TFs) play important roles in plant stress responses and metabolite biosynthesis. In this study, 119 AsAP2/ERF genes were identified from the A. sinensis genome and divided into ERF, AP2, RAV, and Soloist subfamilies. Their conserved motif, gene structure, chromosomal localization, and subcellular localization were characterized. A stress/defense-related ERF-associated amphiphilic repression (EAR) motif and an EDLL motif were identified. Moreover, 11 genes that were highly expressed in the agarwood layer in response to whole-tree agarwood induction technique (Agar-Wit) treatment were chosen, and their expression levels in response to methyl jasmonate (MeJA), salicylic acid (SA), or salt treatment were further analyzed using the quantitative real time PCR (qRT-PCR). Among the 11 genes, eight belonged to subgroup B-3. All 11 genes were significantly upregulated under salt treatment, while eight genes were significantly induced by both MeJA and SA. In addition, the gene clusters containing these upregulated genes on chromosomes were observed. The results obtained from this research not only provide useful information for understanding the functions of AP2/ERF genes in A. sinensis but also identify candidate genes and gene clusters to dissect their regulatory roles in agarwood formation for future research.

Chromosomal-level reference genome of the moth Heortia vitessoides (Lepidoptera: Crambidae), a major pest of agarwood-producing trees

The moth Heortia vitessoides Moore (Lepidoptera: Crambidae) is a major pest of ecologically, commercially and culturally important agarwood-producing trees in the genus Aquilaria. In particular, H. vitessoides is one of the most destructive defoliating pests of the incense tree Aquilaria sinesis, which produces a valuable fragrant wood used as incense and in traditional Chinese medicine [33]. Nevertheless, a genomic resource for H. vitessoides is lacking. Here, we present a chromosomal-level assembly for H. vitessoides, consisting of a 517 megabase (Mb) genome assembly with high physical contiguity (scaffold N50 of 18.2 Mb) and high completeness (97.9% complete BUSCO score). To aid gene annotation, 8 messenger RNA transcriptomes from different developmental stages were generated, and a total of 16,421 gene models were predicted. Expansion of gene families involved in xenobiotic metabolism and development were detected, including duplications of cytosolic sulfotransferase (SULT) genes shared among lepidopterans. In addition, small RNA sequencing of 5 developmental stages of H. vitessoides facilitated the identification of 85 lepidopteran conserved microRNAs, 94 lineage-specific microRNAs, as well as several microRNA clusters. A large proportion of the H. vitessoides genome consists of repeats, with a 29.12% total genomic contribution from transposable elements, of which long interspersed nuclear elements (LINEs) are the dominant component (17.41%). A sharp decrease in the genome-wide percentage of LINEs with lower levels of genetic distance to family consensus sequences suggests that LINE activity has peaked in H. vitessoides. In contrast, opposing patterns suggest a substantial recent increase in DNA and LTR element activity. Together with annotations of essential sesquiterpenoid hormonal pathways, neuropeptides, microRNAs and transposable elements, the high-quality genomic and transcriptomic resources we provide for the economically important moth H. vitessoides provide a platform for the development of genomic approaches to pest management, and contribute to addressing fundamental research questions in Lepidoptera.

Agarwood-The Fragrant Molecules of a Wounded Tree.

Agarwood, popularly known as oudh or gaharu, is a fragrant resinous wood of high commercial value, traded worldwide and primarily used for its distinctive fragrance in incense, perfumes, and medicine. This fragrant wood is created when Aquilaria trees are wounded and infected by fungi, producing resin as a defense mechanism. The depletion of natural agarwood caused by overharvesting amidst increasing demand has caused this fragrant defensive resin of endangered Aquilaria to become a rare and valuable commodity. Given that instances of natural infection are quite low, artificial induction, including biological inoculation, is being conducted to induce agarwood formation. A long-term investigation could unravel insights contributing toward Aquilaria being sustainably cultivated. This review will look at the different methods of induction, including physical, chemical, and biological, and compare the production, yield, and quality of such treatments with naturally formed agarwood. Pharmaceutical properties and medicinal benefits of fragrance-associated compounds such as chromones and terpenoids are also discussed.

Programmed cell death might involve in progress of wounding induced agarwood formation in stems of Aquilaria sinensis.

Agarwood, a non-timber fragrant wood, is derived from wounded Aquilaria trees (Thymelaeaceae) and is widely used in traditional medicine, incense and perfume. Agarwood-like substances and programmed cell death (PCD) can be induced by wounding signals in the suspension cells and aerial roots of Aquilaria sinensis. In this study, the dynamic process of wound-induced agarwood formation in stems of A. sinensis was observed, and the occurrence of PCD was synchronously detected using techniques such as 4',6-diamidino-2-phenylindole and dUTP nick-end labeling staining. The results showed that the wounding was a induce signal for agarwood resin formation, meanwhile might induce PCD. Interxylary phloem and xylem ray were the main sites of agarwood resin formation and PCD occurrence. There might be a relationship between the spatiotemporal pattern of PCD and agarwood resin formation: more severe PCD corresponded to a higher rate of resin formation but a shorter resin formation time; conversely, slower PCD progression corresponded to a lower rate of resin formation but a longer resin formation time. Our findings are the first to demonstrate that PCD might occur in the process of wound-induced agarwood formation at the tree level, and the spatiotemporal pattern is closely related to the formation of agarwood resin. This study provides valuable insight for further studies on the relationship between PCD and agarwood formation. HIGHLIGHTS: Programmed cell death (PCD) might occur in the process of wound-induced agarwood formation at the tree level. Interxylary phloem and xylem ray were the main sites of agarwood resin formation and PCD occurrence. Spatiotemporal pattern of PCD might have a strong impact on agarwood resin formation.

Morphological, physiological, biochemical and molecular analyses reveal wounding-induced agarwood formation mechanism in two types of Aquilaria sinensis (Lour.) Spreng

Agarwood, a resinous portion of injured Aquilaria trees, has become scarce and precious because of its low yields in ordinary Aquilaria sinensis. A new type of A. sinensis, namely easier induced agarwood A. sinensis germplasm (EIAA), has recently been selected and cultivated. However, no information has been reported about its agarwood formation mechanism yet. Multiple approaches, including anatomical, physiological, biochemical and molecular profiling, were employed in this study to investigate wounding-induced agarwood formation in two types of A sinensis. After mechanical damage, the related physiological and biochemical parameters regulating defense response were increased significantly, while the related parameters regulating growth were decreased significantly in two types of A sinensis. The strength of defense response was decreased and the growth performance was recovered over time. Compared to ordinary A. sinensis, EIAA showed higher hormones levels of salicylic acid, jasmonic acid and ethylene, higher activities of antioxidant enzymes, more total phenols and terpenes, higher net photosynthetic rate and photochemical efficiency of PSII, more consumption of non-structural carbohydrates, higher agarwood yield and oil content. There were marked differences in the components of agarwood essential oils between two types of A. sinensis. In particularly for 2-(2-phenylethyl) chromone and 2-[2-(4′-methoxybenzene) ethyl] chromone, their richness in agarwood essential oil of EIAA was significantly higher in contrast with the ordinary A. sinensis agarwood. Differentially expressed genes further ensured the differences in defense responses to wounding stress and secondary metabolism patterns between two types of A. sinensis. These data collectively demonstrate that there is a tradeoff between growth and defense during wounding-induced agarwood formation and EIAA had stronger defense ability in physiological and biochemical levels compared with ordinary A. sinensis. This is the physiological mechanism by which EIAA has higher agarwood yield and essential oil content. Moreover, the differential expression of flavonoid biosynthesis-related genes explained the different chromone synthesis pathways between two types of A. sinensis. These findings provide new insights into wounding-induced agarwood formation mechanism in A. sinensis, especially for EIAA.