To explore the diversity of bacterial community structure between different layers of agarwood, Hiseq(high-throughput sequencing) was used to analyze the bacterial community structure of samples from different layers of agarwood. Our results showed that 1 150 096 optimized sequences and 9 690 OTUs were obtained from 15 samples of 5 layers of agarwood, which belonged to 28 bacterial phyla, 61 classes, 110 orders, 212 families and 384 genera. Further analysis revealed that the normal layer(NL) had the lowest bacterial species richness and the smallest number of OTUs. And the total number of OTUs of the agarwood layer(AL) and NL was zero, which was quite different.At the same time, there were significant differences in bacterial community structure and species diversity between NL and the other four layers. While there were some common dominant bacterial genera in both transition layer(TL) and NL. The similarity of bacterial distribution in 4 non-NL layers was relatively high, which had four common genera, such as Acidibacter, Bradyrhizobium, Acidothemus and Sphingomonas. While Acidibacter, Bradyrhizobium and Acidothemus were the dominant bacterial genus of DA and AL, and all of these layers contained volatile oil. In addition, the Bradyrhizobium was the most abundant in agarwood layer. Our results showed that bacterial community diversity and abundance were decreasing from DL to AL, and different layers showed significant differences in bacterial enrichment. It provided the clues to investigate how bacteria participate in the formation of agarwood.
Bacteria ; High-Throughput Nucleotide Sequencing ; Oils, Volatile ; Thymelaeaceae ; genetics

As an important substitute for agarwood, mountain-agarwood, belonging to the family Oleaceae, comes from the root, stem and thick branch of Syringa pinnatifolia, which has a wide range of application in Inner Mongolia, China. It has good clinical efficacy in the use of cardiovascular diseases. However, the formation speed of mountain-agarwood is extremely slow, and its cultivated seedlings have low resin content. Therefore, how to speed up the formation of mountain-agarwood and increase the resin content is a hot research topic in this field. In this work, 16 S rDNA amplicon sequencing method was used to systematically analyze the bacterial communities of different samples of mountain-agarwood. Our data revealed that the samples of mountain-agarwood had more obvious species diversity than the ones of non-mountain-agarwood, especially the wild mountain-agarwood samples. By analysis of bacterial community composition and species abundance, Sphingomonas, Modestobacter and unidentified Cyanobacteria genus were three dominant bacterial genera in all samples. In addition, there are two identified genera of dominant bacteria, namely Actinoplanes and Microbacterium in both wild and cultivated mountain-agarwood, by bacterial community composition and species richness analysis. Meanwhile, Roseomonas was the dominant bacterial genus in both wild and cultivated non-mountain-agarwood samples. Our work could provides basic data for exploring the mechanism of the mountain-agarwood formation, and help to exploit resource of endophytic bacteria reasonably.
Bacteria ; genetics ; China ; DNA, Ribosomal ; Resins, Plant ; Thymelaeaceae

"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.
Phylogeny ; Genome, Chloroplast ; Codon ; Molecular Sequence Annotation ; Thymelaeaceae/genetics*

Farnesyl diphosphate synthase (FPS) is one of the key rate-limiting enzymes in the sesquiterpene metabolic pathways. In this study, the open reading frame (ORF) of FPS was cloned by PCR based on the transcript sequence of AsFPS1 from the Aquilaria sinensis transcriptome database and sequenced. Total RNA was extracted from the root, stem and leaves of three-year-old A. sinensis, and from healthy and wounded A. sinensis calli, and then reverse-transcribed into single-stranded cDNA as a template for real-time PCR, to detect the expression specificity of AsFPSI in different tissues and its expression profile in responding to different treatments. The result showed that the full length of AsFPS1 was 1 342 bp with the ORF 1 029 bp, encoding 342 amino acids. Tissue expression analysis indicated that AsFPS1 was mainly expressed in root and stem, and was lower in leaves. Inducible-experiments showed that the genes was induced by mechanical wound as well as chemical liquid induction, and reached the highest expression level at 6 h and 12 h, respectively. The full-length cDNA clone of AsFPSI and its expression patterns analysis will provide a foundation for follow-up study on its biological function and agarwood sesquiterpene biosynthesis mechanism.
DNA, Complementary ; genetics ; Geranyltranstransferase ; genetics ; metabolism ; Real-Time Polymerase Chain Reaction ; Thymelaeaceae ; enzymology ; genetics ; metabolism

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.
Bacteria ; classification ; genetics ; isolation & purification ; Biodiversity ; Endophytes ; classification ; genetics ; isolation & purification ; Thymelaeaceae ; microbiology ; Wood ; microbiology

OBJECTIVEThe research focused on identification the pathogen of Aquilaria sinensis dieback disease and confirmation the function of inducing agarwood formation by fungi.

METHODThe morphological observation, rDNA ITS sequence analyses, Koch's postulates and pathogenicity test were used to identify the isolates.

RESULTThe isolates of the causal agent was Lasiodiplodia theobromae, which induced the plant to produce highly valuable agarwood.

CONCLUSIONThe first report of dieback disease of Aquilaria sinensis caused by L. theobromae, and our research results laid a theoretical foundation for agarwood production by using fungus.

Fungi ; classification ; genetics ; isolation & purification ; physiology ; Molecular Sequence Data ; Phylogeny ; Plant Diseases ; microbiology ; Thymelaeaceae ; microbiology

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.
Cluster Analysis ; DNA, Fungal ; genetics ; Endophytes ; classification ; genetics ; physiology ; Fusarium ; classification ; genetics ; physiology ; Phylogeny ; Plant Leaves ; metabolism ; Thymelaeaceae ; microbiology ; Wood ; metabolism ; microbiology

A sesquiterpene synthase (AsSS4) full-length open reading frame (ORF) cDNA was cloned from wounded stems of Aquilaria sinensis by RT-PCR method. The result showed that the ORF of AsSS4 was 1,698 bp encoding 565 amino acids. Prokaryotic expression vector pET28a-AsSS4 was constructed and transformed into E. coli BL21 (DE3) pLysS. Recombinant AsSS4 protein was obtained after induction by IPTG and SDS-PAGE analysis with a MW of 64 kD. Enzymatic reactions using farnesyl pyrophosphate showed that recombinant AsSS4 protein purified by Ni-agarose gel yielded five sesquiterpene compounds, cyclohexane, 1-ethenyl-1-methyl-2, 4-bis(1-methylethenyl)-, β-elemene, α-guaiene, α-caryophyllene and δ-guaiene. This paper reported the first cloning and functional characterization of AsSS4 gene from A. sinensis, which will establish a foundation for future studies on the molecular mechanisms of wound-induce agarwood formation in A. sinensis
Alkyl and Aryl Transferases ; biosynthesis ; genetics ; Azulenes ; Cloning, Molecular ; DNA, Complementary ; Escherichia coli ; Open Reading Frames ; Polyisoprenyl Phosphates ; Recombinant Proteins ; biosynthesis ; Sesquiterpenes ; metabolism ; Sesquiterpenes, Guaiane ; Thymelaeaceae ; enzymology ; genetics

Chinese agarwood is formed in the aromatic resinous wood formed in Aquilaria sinensis (Lour.) Gilg (botanical family: Thymelaeaceae). Only when suffering stress of wound, etc, can A. sinensis produce sesquiterpenes etc. compounds of agarwood around wounds. However, little is known about how wound induced the biosynthesis pathway of sesquiterpenes. To reveal the molecular mechanism of wound-induced agarwood formation, RNA sequencing (RNA-seq) technology was used to investigate the profile of gene expression in A. sinensis treated by mechanical wounding and elucidate its functional gene. A total of 40,295 ESTs with an average read length of 305 bp were generated and 22 095 unigenes were formed by initial gene splicing. 61.6% of these unigenes (13 611) were annotated using BLAST searches against the SwissProt, KEGG, Nr and Nt databases. Twenty-six unigenes (encoding 7 enzymes) were found to be involved in sesquiterpene of agarwood biosynthesis by bioinformatic tools of Gene Ontology and KEGG. Novel genes that are potentially involved in sesquiterpenes biosynthesis were identified in A. sinensis, providing data for further sesquiterpenes biosynthesis pathway by molecular methods and the EST data establish a foundation for future studies in the molecular mechanisms of wound-induce agarwood formation in A. sinensis.
Drugs, Chinese Herbal ; chemistry ; metabolism ; Expressed Sequence Tags ; Genes, Plant ; genetics ; Plants, Medicinal ; chemistry ; genetics ; Sequence Analysis, RNA ; Sesquiterpenes ; chemistry ; metabolism ; Stress, Physiological ; genetics ; Thymelaeaceae ; chemistry ; genetics ; Transcriptome ; genetics ; Wood ; genetics ; metabolism

The study aimed to clone the open reading frame of cinnamate 4-hydroxylase (C4H) from Aquilaria sinensis and analyze the bioinformatics and expression of the gene. One unique sequence containing C4H domain was discovered in our previous reported wound transcriptome dataset of A. sinensis. The open reading frame of C4H was cloned by RT-PCR strategy with the template of mixed RNA extracted from A. sinensis stem which treated by different wound time. The bioinformatic analysis of this gene and its corresponding protein was performed. C4H expression profiles in responds to MeJA (methyl jasmonate) application were analyzed by real-time PCR. The length of C4H open reading frame (ORF) was 1 515 bp, encoding 514 amino acids. The GenBank accession number is KF134783. Inducible-experiments showed that the genes were induced by mechanical wound as well as MeJA induction, and reached the highest expression level at 8 h and 20 h, respectively. The full-length cDNA of C4H and its expression patterns will provide a foundation for further research on its function in the molecular mechanisms of aromatic compounds and flavonoids biosynthesis.
Amino Acid Sequence ; Cloning, Molecular ; Models, Molecular ; Molecular Sequence Data ; Open Reading Frames ; Oxidoreductases ; chemistry ; genetics ; metabolism ; Phylogeny ; Plant Proteins ; chemistry ; genetics ; metabolism ; Thymelaeaceae ; chemistry ; enzymology ; genetics ; Trans-Cinnamate 4-Monooxygenase ; chemistry ; genetics ; metabolism