Diaporchalasins A-E, New Cytochalasins from the Endophytic Fungus Diaporthe sp. BMX12 Isolated from Aquilaria sinensis.

Five new cytochalasins, diaporchalasins A-E (1-5), together with 14 known congeners (6-19) were isolated from the endophytic fungus Diaporthe sp. BMX12, which was isolated from the branches of Aquilaria sinensis. The structures of the new compounds were elucidated by extensive spectroscopic analyses including high-resolution electron spray ionization mass spectrometry (HR-ESI-MS) and nuclear magnetic resonance (NMR). Their absolute configurations were assigned by theoretical electronic circular dichroism (ECD) calculations. Compounds 11 and 12 featuring a keto carbonyl at C-21 displayed cytotoxicity toward K562, BEL-7402, SGC-7901, A549, and HeLa cell lines with IC50 values ranging from 4.4 to 47.4 µM.

Endophytic bacterial community of Stellera chamaejasme L. and its role in improving host plants' competitiveness in grasslands.

Stellera chamaejasme has become a problematic weed in northern and south-western grasslands of China. To evaluate a possible role of endophytes in its strong competitive capacity, the endophytic bacterial community of S. chamaejasme was investigated by culture-dependent and independent methods, and the growth-promoting traits of some culturable isolates as well as the benefit of endophyte ST3CS3 (Brevundimonas sp.) on host plants growth were studied. The results showed that 823 OTUs were generated with a 97% similarity level in the culture-independent study. They were classified into 29 phyla, 61 classes, 147 orders, 237 families and 440 genera. Among them, Pseudomonas and Ralstonia were the most dominant genera in belowground parts (G) (64.25%) and aboveground parts (S) (26.54%) respectively. The diversity and species richness of endophytes in S were significantly higher than that of G (P < 0.001, t-test). Contrary to this, the number of culturable bacteria in S was a little lower than that of G (P > 0.05, t-test). Totally, 176 isolates belonging to 30 morphotypes were obtained in the culture-dependent study. Among them, Acinetobacter was the most dominant genus in G (51.30%), then followed by Pseudomonas (6.09%) and Brevundimonas (6.09%), while Lysinibacillus (21.31%) was the most dominant genus in S, followed by Pseudomonas (11.48%). Growth-promoting trait tests indicated that 93.65% of the tested isolates (63) exhibited nitrogen-fixing, IAA-synthesizing, phosphorus or potassium solubilizing capacity, in which 77.97% belonged to Proteobacteria, a phylum found to contain more active isolates. Pot experiments demonstrated that endophyte ST3CS3 can significantly improve host plants growth and increase its nitrogen and chlorophyll content (P < 0.01, t-test). Therefore, we suggest that strong competitiveness of S. chamaejasme may in part be due to possession of high ratios of plant growth-promoting proteobacterial endophytes such as Pseudomonas, Acinetobacter and Brevundimonas.

Production of Volatile Compounds by a Variety of Fungi in Artificially Inoculated and Naturally Infected Aquilaria malaccensis.

Aquilaria malaccensis, the resinous agarwood, is highly valued in the perfumery and medicinal industry. The formation of fragrant agarwood resin inconsistently by various fungi is still not clearly understood. The current study investigated the agarwood quality and fungal diversity in artificially inoculated and naturally infected A. malaccensis. The chemical analysis of volatile compounds of agarwood was performed using the Solid Phase Micro Extraction (SPME) method, and the identification of fungi was made through a morphological observation using a light microscope. Gas chromatography analysis revealed the presence of essential compounds related to high-quality agarwood, such as 4-phenyl-2-butanone, ß-selinene, α-bulnesene, and agarospirol in both artificially inoculated and naturally infected agarwood but with some differences in the abundance. Further studies on the fungi associated with agarwood volatile compounds formation showed a total of ten fungal group isolates, which were identified based on morphological and molecular studies. The study revealed that agarwood from both artificial and natural sources were naturally infected with Fusarium, Botryosphaeria, Aspergillus, Schizophyllum, Phanerochaete, Lasiodiplodia, Polyporales, and Ceriporia species. This study has offered a potential opportunity to research further the promising development of fungal strains for artificial inducement of high-quality agarwood formation from A. malaccensis trees.

Isolation and Characterization of Bacteria and Fungi Associated with Agarwood Fermentation.

Agarwood oil, often called attar, is a valuable perfume retainer derived from Aquilaria malaccensis. It is obtained through a process of fermentation followed by distillation. The microbes involved in fermentation during agarwood processing have neither been documented nor their role in the process deciphered yet. The present study characterizes the fungi and bacteria engaged in the agarwood fermentation and assesses their colony forming units (CFU) in three categories of agarwood fermentation broth (AFB) collected from three small-scale industries of Hojai, Assam at varying time points. It was interesting to note that grade-A AFB contained the highest CFU count for both bacteria and fungi; the metabolite profile also revealed that the oil obtained from grade-A agarwood comprised of the highest number of compounds. The CFU count increased from 0 to 21 days during fermentation. A total of 105 bacteria and 9 fungi were isolated from 3 different grades of AFB. Shannon index (H' = 0.81) was observed maximum in grade-C AFB and fisher index (α = 2.6) observed maximum for grade-A AFB. The genus Bacillus with a Pi value of 0.61 exhibited dominance among isolated bacteria, while the genus Galactomyces was dominant among fungi with a Pi value of 0.43. The metabolite profiles of three grades of oil obtained after fermentation and one solvent extracted (S.E.) grade agarwood oil analyzed using GC-MS, which showed distinct differences among the oil. The outcomes of this study are expected to create new opportunities for improving oil production methods by modulating biochemical processes involved in fermentation.

Saprophytic Bacillus Accelerates the Release of Effective Components in Agarwood by Degrading Cellulose.

The value of Agarwood increases with time due to the gradual release of its major components, but the mechanism behind this remains unclear. Herein we reveal that the potential driving force of this process is the degradation of cellulose in Agarwood by its saprophytic Bacillus subtilis. We selected 10-year-old Agarwood from different places and then isolated the saprophytic bacteria. We confirmed these bacteria from different sources are all Bacillus and confirmed they can degrade cellulose, and the highest cellulase activity reached 0.22 U/mL. By co-cultivation of the bacterium and Agarwood powder, we found that three of the strains could release the effective components of Agarwood, while they had little effect in increasing the same components in living Aquilaria sinensis. Finally, we demonstrated that these saprophytic Bacillus subtilis have similar effects on Zanthoxylum bungeanum Maxim and Dalbergiaod orifera T. Chen, but not on Illicium verum Hook. f, Cinnamomum cassia Presl and Phellodendron chinense Schneid. In conclusion, our experiment revealed that the saprophytic Bacillus release the effective components of Agarwood by degrading cellulose, and we provide a promising way to accelerate this process by using this bacterial agent.

Aromatic Polyketides from a Symbiotic Strain Aspergillus fumigatus D and Characterization of Their Biosynthetic Gene D8.t287.

The chemical investigation of one symbiotic strain, Aspergillus fumigatus D, from the coastal plant Edgeworthia chrysantha Lindl led to the isolation of eight compounds (1-8), which were respectively identified as rubrofusarin B (1), alternariol 9-O-methyl ether (2), fonsecinone D (3), asperpyrone A (4), asperpyrone D (5), fonsecinone B (6), fonsecinone A (7), and aurasperone A (8) by a combination of spectroscopic methods (1D NMR and ESI-MS) as well as by comparison with the literature data. An antimicrobial assay showed that these aromatic polyketides exhibited no remarkable inhibitory effect on Escherichia coli, Staphyloccocus aureus and Candida albicans. The genomic feature of strain D was analyzed, as well as its biosynthetic gene clusters, using antibiotics and Secondary Metabolite Analysis Shell 5.1.2 (antiSMASH). Plausible biosynthetic pathways for dimeric naphtho-γ-pyrones 3-8 were first proposed in this work. A non-reducing polyketide synthase (PKS) gene D8.t287 responsible for the biosynthesis of these aromatic polyketides 1-8 was identified and characterized by target gene knockout experiment and UPLC-MS analysis.

Mycolicibacterium stellerae sp. nov., a rapidly growing scotochromogenic strain isolated from Stellera chamaejasme.

A polyphasic study was undertaken to establish the taxonomic provenance of a rapidly growing Mycolicibacterium strain, CECT 8783T, recovered from the plant Stellera chamaejasme L. in Yunnan Province, China. Phylogenetic analyses based upon 16S rRNA and whole-genome sequences showed that the strain formed a distinct branch within the evolutionary radiation of the genus Mycolicibacterium. The strain was most closely related to Mycolicibacterium moriokaense DSM 44221T with 98.4 % 16S rRNA gene sequence similarity, but was distinguished readily from this taxon by a combination of chemotaxonomic and phenotypic features and by low average nucleotide identity and digital DNA-DNA hybridization values of 79.5 and 21.1 %, respectively. Consequently, the strain is considered, to represent a novel species of Mycolicibacterium for which the name Mycolicibacterium stellerae sp. nov is proposed; the type strain is I10A-01893T (=CECT 8783T=KCTC 19843T=DSM 45590T).

Evaluation of three different artificial agarwood-inducing methods from Aquilaria sinensis using antimicrobial activity.

The aim of this paper was to evaluate the effect of three different approaches for artificially inducing the formation of agarwood over time in young Aquilaria sinensis trees using antimicrobial activity. The antimicrobial activity was determined by a two-fold serial dilution method and minimum inhibitory concentration (MIC) against a panel of microorganisms (two bacterial strains, Staphylococcus aureus and anti-methicillin-resistant Staphylococcus aureus, and seven fungal strains: Penicillium melinii, Penicillium adametzi, Penicillium urticae, Penicillium notatum, Paecilomyces varioti, Mucor saturninus Hagem and Aspergillus niger). The results showed that artificial agarwood obtained by comprehensive stimulated method (formic acid plus fungal inoculation) and extended longer inducing time have better antimicrobial activity, which is similar to the result of chemical analysis. Therefore, it is a beneficial exploration to the first use of antimicrobial activity to evaluate artificial agarwood obtained by different producing methods and different culture time.

Monitoring the Chemical Profile in Agarwood Formation within One Year and Speculating on the Biosynthesis of 2-(2-Phenylethyl)Chromones.

Agarwood is highly valued for its uses as incense, perfume, and medicine. However, systematic analyses of dynamic changes of secondary metabolites during the process of agarwood formation have not yet been reported. In this study, agarwood was produced by transfusing the agarwood inducer into the trunk of Aquilaria sinensis, and changing patterns of chemical constituents, especially 2-(2-phenylethyl)chromones (PECs), in wood samples collected from the 1st to 12th month, were analyzed by GC-EI-MS and UPLC-ESI-MS/MS methods. Aromatic compounds, steroids, fatty acids/esters, sesquiterpenoids, and PECs were detected by GC-MS, in which PECs were the major constituents. Following this, UPLC-MS was used for further comprehensive analysis of PECs, from which we found that 2-(2-phenylethyl)chromones of flindersia type (FTPECs) were the most abundant, while PECs with epoxidated chromone moiety were detected with limited numbers and relatively low content. Speculation on the formation of major FTPECs was fully elucidated in our context. The key step of FTPECs biosynthesis is possibly catalyzed by type III polyketide synthases (PKSs) which condensate dihydro-cinnamoyl-CoA analogues and malonyl-CoA with 2-hydroxy-benzoyl-CoA to produce 2-(2-phenyethyl)chromone scaffold, or with 2,5-dihydroxybenzoyl-CoA to form FTPECS with 6-hydroxy group, which may serve as precursors for further reactions catalyzed by hydroxylase or O-methyltransferase (OMT) to produce FTPECs with diverse substitution patterns. It is the first report that systematically analyzed dynamic changes of secondary metabolites during the process of agarwood formation and fully discussed the biosynthetic pathway of PECs.

Humibacter aquilariae sp. nov., an actinobacterium isolated from an agarwood chip.

A polyphasic taxonomic approach was used to characterize a presumably novel bacterium, designated strain CC-YTH161T, isolated from an agarwood sample. Cells of strain CC-YTH161T were Gram-stain-positive aerobic rods, which grew at 20-40 °C, at pH 5.0-9.0 and with 0-5 % (w/v) NaCl. On the basis of 16S rRNA gene sequence analysis, strain CC-YTH161T appeared to belong to the genus Humibacter, and was closely related to Humibacter antri D7-27T (96.6 % similarity) and Humibacter ginsengiterrae DCY60T (96.2 %). The DNA G+C content was 67.0 mol% and the predominant quinone system was menaquinones (MK) 11 and 12. The major cellular fatty acids of the isolate were C15 : 0, iso-C16 : 0, anteiso-C17 : 0 and C18 : 1ω7c/C18 : 1ω6c. The polar lipid profile comprised predominant amounts of diphosphatidylglycerol followed by two unidentified co-migrating glycolipids and phosphatidylglycerol in significant amounts. The diagnostic diamino acid was 2,4-diaminobutyric acid. All these features confirmed the placement of strain CC-YTH161T within the genus Humibacter. On the basis of evidence from this study, strain CC-YTH161T is considered to represent a novel species of the genus Humibacter, for which the name Humibacter aquilariae sp. nov. is proposed. The type strain is CC-YTH161T (=BCRC 80936T=JCM 31199T).

Filimonas aquilariae sp. nov., isolated from agarwood chips.

A polyphasic approach was used to characterize a Gram-staining negative bacterium (designated strain CC-YHH650T) isolated from agarwood chips. Strain CC-YHH650T was aerobic and rod-shaped, able to grow at 15-37 °C (optimal 30 °Ð¡), pH 6.0-8.0 (optimal 7.0) and 0-1 % (w/v) NaCl (optimal 0 %). Phylogenetic analysis based on 16S rRNA genes revealed that strain CC-YHH650T shared highest sequence similarities with Filimonas lacunae (97.5 %), F. zeae (97.4 %), F. endophytica (97.3 %) and F. aurantiibacter (93.0 %), and lower sequence similarity with other genera (less than 93.0 %). The levels of DNA-DNA relatedness between strain CC-YTH209T, F. lacunae, F. endophytica and F. zeae were estimated to be 18.3, 6.1, 24.7 % (the reciprocal values were 9.8, 8.8, 18.3 %). The major fatty acids were iso-C15 : 0, iso-C15 : 1 G, C16 : 0 3-OH, iso-C17 : 0 3-OH and C16 : 1ω7c/C16 : 1ω6c. The polar lipid profile contained phosphatidylethanolamine, an unidentified phospholipid, two unidentified aminophospholipids, three unidentified aminolipids and three unidentified lipids. The DNA G+C content was 46.6 mol% and the predominant quinone was menaquinone-7 (MK-7). The major polyamine was sym-homospermidine. Based on the distinct phylogenetic, phenotypic and chemotaxonomic traits together with results of comparative 16S rRNA gene sequence analysis, strain CC-YHH650T is considered to represent a novel species of the genus Filimonas, for which the name Filimonas aquilariae sp. nov. is proposed. The type strain is CC-YHH650T (=BCRC 80935T=JCM 31197T).

Fungal Endophytes: an Alternative Source for Production of Volatile Compounds from Agarwood Oil of Aquilaria subintegra.

Fungal endophytes are microorganisms that are well-known for producing a diverse array of secondary metabolites. Recent studies have uncovered the bioprospecting potential of several plant endophytic fungi. Here, we demonstrate the presence of highly bioactive fungal endophytic species in Aquilaria subintegra, a fragrant wood plant collected from Thailand. Thirty-three fungal endophytic strains were isolated and further identified to genus level based on morphological characteristics. These genera included Colletotrichum, Pestalotiopsis, Fusarium, Russula, Arthrinium, Diaporthe and Cladosporium. All strains were cultured on potato dextrose broth for 30 days prior to partitioning with ethyl acetate. The volatile compounds of all extracts were investigated by gas chromatography-mass spectrometry (GC-MS). Four strains-Arthrinium sp. MFLUCC16-0042, Colletotrichum sp. MFLUCC16-0047, Colletotrichum sp. MFLUCC16-0048 and Diaporthe sp. MFLUCC16-0051-produced a broad spectrum of volatile compounds, including ß-agarofuran, α-agarofuran, δ-eudesmol, oxo-agarospirol, and ß-dihydro agarofuran. These compounds are especially important, because they greatly resemble those originating from the host-produced agarwood oil. Our findings demonstrate the potential of endophytic fungi to produce bioactive compounds with applications in perfumery and cosmetic industries. Antioxidant activity of all extracts was also evaluated by using 2,2-diphenyl-2-picrylhydrazyl radical scavenging assays. The ethyl acetate extract of Diaporthe sp. MFLUCC16-0051 demonstrated superior antioxidant capacity, which was comparable to that of the gallic acid standard. Our results indicate that the MFLUCC16-0051 strain is a resource of natural antioxidant with potential medicinal applications.

Agarwood Formation Induced by Fermentation Liquid of Lasiodiplodia theobromae, the Dominating Fungus in Wounded Wood of Aquilaria sinensis.

Agarwood is broadly used in incense and medicine. Traditionally, agarwood formation is induced by wounding the trunks and branches of some species of Aquilaria spp., including A. sinensis. As recently evidenced, some fungi or their fermentation liquid may have the potential of inducing agarwood formation. The present study aimed to analyze the fungi isolated from an agarwood-producing A. sinensis tree and subsequently identify the fungi capable of promoting agarwood formation. We identified a total of 110 fungi isolates based on their morphological characteristics and rDNA ITS sequences. These isolates came from four different layers (namely the decomposing layer, agarwood layer, transition layer, and normal layer) near the agarwood formation site of the trunk. According to the experimental results, most of them belonged to Dothideomycetes (81.82%), while the others to Sordariomycetes (13.64%) or Eurotiomycetes (4.55%). Of note, 88 isolates were shown belonging to the species of Lasiodiplodia theobromae that are most frequently isolated from different layers. In addition, when the fermentation liquid of two isolates of L. theobromae (AF4 and AF12) and one isolate of Fusarium solani (AF21) was inoculated into the A. sinensis wood using the Agar-Wit technique, promoted agarwood formation was observed; however, the effect of AF21 did not keep stable in the later test, while AF4 and AF12 still functioned 1 year later. This study may lay a foundation for exploring the underlying mechanism of agarwood formation as well as fungi application in agarwood production.

Guanacastane-type diterpenoids from the insect-associated fungus Verticillium dahliae.

Four new guanacastane-type diterpenoids, namely dahlianes A (1), B (2), C (3), and D (4), were isolated from cultures of Verticillium dahliae. Their structures were elucidated on the basis of extensive spectroscopic data analysis. Their absolute configurations were determined by a combination of Mo2(OAc)4-induced electronic circular dichroism experiment and Mosher ester method. In cytotoxicity evaluation against human tumor cell lines, compounds 2 and 3 exhibited significant cytotoxicities against MCF-7 cell lines with IC50 values of 3.35 and 4.72 µM, respectively.

Phylogenic diversity and tissue specificity of fungal endophytes associated with the pharmaceutical plant, Stellera chamaejasme L. revealed by a cultivation-independent approach.

The fungal endophytes associated with medicinal plants have been demonstrated as a reservoir with novel natural products useful in medicine and agriculture. It is desirable to explore the species composition, diversity and tissue specificity of endophytic fungi that inhabit in different tissues of medicinal plants. In this study, a culture-independent survey of fungal diversity in the rhizosphere, leaves, stems and roots of a toxic medicinal plant, Stellera chamaejasme L., was conducted by sequence analysis of clone libraries of the partial internal transcribed spacer region. Altogether, 145 fungal OTUs (operational taxonomic units), represented by 464 sequences, were found in four samples, of these 109 OTUs (75.2 %) belonging to Ascomycota, 20 (13.8 %) to Basidiomycota, 14 (9.7 %) to Zygomycota, 1 (0.7 %) to Chytridiomycota, and 1 (0.7 %) to Glomeromycota. The richness and diversity of fungal communities were strongly influenced by plant tissue environments, and the roots are associated with a surprisingly rich endophyte community. The endophyte assemblages associated with S. chamaejasme were strongly shaped by plant tissue environments, and exhibited a certain degree of tissue specificity. Our results suggested that a wide variety of fungal assemblages inhabit in S. chamaejasme, and plant tissue environments conspicuously influence endophyte community structure.

[Community structure and difference of endophtic bacteria in Aquilaria sinensis with and without agarwood].

Aquilaria sinensis can generate agarwood, which is closely related with endophyte. Up to now, studies mainly focused on the effects of endophytic fungi on agarwood formation, but studies about endophytic bacteria are rarely reported. In our research, the T-RFs and Shannon index of endophytic bacteria in samples of agarwood increase. The number of distinctive T-RFs fragments of corresponding samples in the same group accounted for more than 60% the number of total T-RFs fragments. In samples of no-agarwood, the dominant bacterial population are Anoxybacillus, Clostridium, Candidatus endobugula, Lysinibacillus. In samples of agarwood, the dominant bacterial population are Clostridium, Lysinibacillus, Luteimonas, phytoplasma. Besides, there are. specific T-RFs fragment in samples of agarwood and no-agarwood respectively. When we perform cluster analysis, we found samples of agarwood highly gather together and samples of no-agarwood highly gather together. This means community of endophytic bacteria emerge significant and regular changes during agarwood formation, which may be result of agarwood production, or maybe it is important reason of agarwood production. In this paper, we obtain more comprehensive and accurate community of endophytic bacteria in Aquilaria sinensis and it's variation during agarwood formation using T-RFLP, which is first study of effects of endophytic bacteria on agarwood formation, and will help to exploit resource of endophytic bacteria more reasonably.

The sesquiterpene biosynthesis and vessel-occlusion formation in stems of Aquilaria sinensis (Lour.) Gilg trees induced by wounding treatments without variation of microbial communities.

As widely recognized, agarwood formation in Aquilaria trees is induced by external wounding. Because agarwood usually harbors specific microbes, the function of microbes in agarwood formation has been debated for almost a century. In this study, two wounding methods, the burning-chisel-drilling method (BCD) and the whole-tree agarwood-inducing method (Agar-Wit), were used under the non-contamination of environmental microorganisms. After pyrosequencing the small rRNA subunits of the wounds induced by the BCD and Agar-Wit, no substantial variation was observed either in fungal and bacterial enrichment and diversity or in the relative abundances of taxa. By contrast, significant variations in fungal and bacterial communities were detected following the partial tree pruning (PTP)-wounding. The wound-induced sesquiterpene biosynthesis and vessel-occlusion formation, however, were found to be similar in all types of wounded trunks. We thus infer that wounding in the absence of variations in microbial communities may induce agarwood formation. This result does not support the long-standing notion that agarwood formation depends on microbes.

Succession patterns of fungi associated to wound-induced agarwood in wild Aquilaria malaccensis revealed from quantitative PCR assay.

Aquilaria malaccensis produces agarwood in response to wounding and fungal attack. However, information is limited regarding Aquilaria's interaction with its diverse fungal community. In this study, time-related changes of three natural fungal colonizers in two wounded wild A. malaccensis were tracked, beginning a few hours after wounding up to 12 months. Using species-specific primers derived from their nrITS sequences in quantitative real-time PCR (qPCR), we quantified the amount of Cunninghamella bainieri, Fusarium solani and Lasiodiplodia theobromae. Because time is a major factor affecting agarwood quantity and quality, 14 wood samples were collected at different time points, i.e., 0-18 h, 2-13 days, 2-18 weeks, and 6-12 months after wounding. qPCR data revealed that the abundance of the three species decreased over time. The fungi were detected in high numbers during the first few hours and days after wounding (40- to 25,000-fold higher levels compared with initial counts) and in low numbers (<1- to 3,200-fold higher than initially) many months later. Consistent with its role in defense response, the accumulation of secondary metabolites at the wounding site could have caused the decline in fungal abundance. Succession patterns of the two trees were not identical, indicating that fungal populations may have been affected by tree environment and wound microclimate. Our results are important for understanding the diversity of microbial community in wild Aquilaria species and their association to wound-induced agarwood formation. Fungi could be secondary triggers to agarwood production in situations where trees are wounded in attempt to induce agarwood.

[Effects of agarwood formation induced by Fusarium sp. A2 on distribution and community composition of endophytic fungi in leaves of Aquilaria sinensis].

The aim of the paper is to observe the distribution of the endophytic fungi in leaves of Aquilaria sinensis by using permanent paraffin-cut section, optical microscope photography and histochemistry. Total DNA was extracted with modified CTAB method and rDNA ITS regions of plant and endophytic fungi were amplified with eukaryotic universal primers. The rDNA ITS amplicon was characterized by RFLP analysis, sequencing of rDNA ITS library and phylogenetic analyses using PAUP by maximum parsimony. Fusarium sp. A2 was used to induce the formation of resinous in A. sinensis trees. As a result, endophytic fungi mainly distributed in spongy and phloem in leaf. Endophytic fungi distributed in the phloem in agarwood-producing tree and had a relatively high abundance. Phoma sp. and Collectrotrichum sp. were the absolute advantage species in the leaf tissues of non-resinous and agarwood-producing tree, respectively. Collectrotrichum sp. was the only fungal species detected both in the two types of A. sinensis with different levels of abundance. The culture-independent molecular method can be used to identify fungal species directly and rapidly from the plant tissues. Endophytic fungal communities in non-resinous and agarwood-producing A. sinensis leaf tissues were quite different.

[Study of production of sesquiterpenes of Aquilaria senensis stimulated by Lasiodiplodia theobromae].

To investigate the mechanism of agarwood formation in Aquilaria sinensis induced by Lasiodiplodia theobromae, the fermentation liquor of L. theobromae was analyzed qualitatively and quantitatively by gas chromatography-mass spectrometry (GC-MS). JAs were detected in the fermentation liquor. The effect of the fermentation liquor on the abundance of sesquiterpenes in the callus of A. sinensis was analyzed by solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS). And the fermentation liquor stimulated alpha-guaiene, alpha-humulene and delta-guaiene biosynthesis in calli. It was inferred that L. theobromae produced JAs, which resulted in a significant increase of sesquiterpenes in A. sinensis.