Dendrocalamus Sinicus Research Articles

Analysis of culm elongation in photoheterotrophic status of Dendrocalamus sinicus by comparative proteomics

The differential expression of 36 proteins plays a central role in culm elongation during photoheterotrophic status, which was involved in complicated biochemical and molecular processes, including replication, transcription, translation, energy metabolism, central intermediary metabolism, and woody tissue photosynthesis. Dendrocalamus sinicus is known as the largest bamboo species in the world, characterized by huge woody culms with rapid growth rate. During culm elongation, leaves are not yet shaped and culms are covered by nontransparent overlapping sheaths, forming a photoheterotrophic status in which culms rapidly complete their own growth. To elucidate this phenomenon, proteome analysis as well as enzyme activity were performed. In terms of the enzyme activity, we found significant differences among internodes for adenosine diphosphoglucose pyrophosphorylase, starch synthase, and starch branching enzyme, implying existence of a robust response of starch synthesis throughout culm elongation. At the protein level, 2-DE combined with MALDI–TOF/TOF MS analysis showed 36 differentially accumulated proteins among internodes. Of which, the largest group is the cluster for energy metabolism (27.78%), followed by central intermediary metabolism (22.22%), which suggests that carbohydrate metabolism dominates the process of culm elongation. Especially, four proteins related to the glycolysis pathway were differentially expressed. In addition, a protochlorophyllide reductase associated with chlorophyllide synthesis was down-regulated from basal to top internodes. This implies that culms belong to photosynthetic tissue and woody tissue photosynthesis is involved in the culm elongation. In addition, malate dehydrogenase related to TCA cycle was up-regulated from tender to mature tissues, which indicates that it plays a vital role in energy generation. An inconsistency between the transcript and protein level was found, suggesting that post-transcriptional events are involved in the culm elongation. These results are helpful to disclose the multiple mechanism of culm elongation of D. sinicus.

Transcriptome Sequencing and Analysis for Culm Elongation of the World's Largest Bamboo (Dendrocalamus sinicus).

Dendrocalamus sinicus is the world’s largest bamboo species with strong woody culms, and known for its fast-growing culms. As an economic bamboo species, it was popularized for multi-functional applications including furniture, construction, and industrial paper pulp. To comprehensively elucidate the molecular processes involved in its culm elongation, Illumina paired-end sequencing was conducted. About 65.08 million high-quality reads were produced, and assembled into 81,744 unigenes with an average length of 723 bp. A total of 64,338 (79%) unigenes were annotated for their functions, of which, 56,587 were annotated in the NCBI non-redundant protein database and 35,262 were annotated in the Swiss-Prot database. Also, 42,508 and 21,009 annotated unigenes were allocated to gene ontology (GO) categories and clusters of orthologous groups (COG), respectively. By searching against the Kyoto Encyclopedia of Genes and Genomes Pathway database (KEGG), 33,920 unigenes were assigned to 128 KEGG pathways. Meanwhile, 8,553 simple sequence repeats (SSRs) and 81,534 single-nucleotide polymorphism (SNPs) were identified, respectively. Additionally, 388 transcripts encoding lignin biosynthesis were detected, among which, 27 transcripts encoding Shikimate O-hydroxycinnamoyltransferase (HCT) specifically expressed in D. sinicus when compared to other bamboo species and rice. The phylogenetic relationship between D. sinicus and other plants was analyzed, suggesting functional diversity of HCT unigenes in D. sinicus. We conjectured that HCT might lead to the high lignin content and giant culm. Given that the leaves are not yet formed and culm is covered with sheaths during culm elongation, the existence of photosynthesis of bamboo culm is usually neglected. Surprisedly, 109 transcripts encoding photosynthesis were identified, including photosystem I and II, cytochrome b6/f complex, photosynthetic electron transport and F-type ATPase, and 24 transcripts were characterized as antenna proteins that regarded as the main tool for capturing light of plants, implying stem photosynthesis plays a key role during culm elongation due to the unavailability of its leaf. By real-time quantitative PCR, the expression level of 6 unigenes was detected. The results showed the expression level of all genes accorded with the transcriptome data, which confirm the reliability of the transcriptome data. As we know, this is the first study underline the D. sinicus transcriptome, which will deepen the understanding of the molecular mechanisms of culm development. The results may help variety improvement and resource utilization of bamboos.

A Study on the Conservation and Development of <i>Dendrocalamus sinicus</i> Form Yunnan, China

Dendrocalamus sinicus is an endemic species in southwestern Yunnan, China, and it is the the largest bamboo in the world. It can grow to more than 30m tall with 30cm in diameter. Its culms yield per unit area is 5-8 times as that of Phyllostachys pubscens that is now popularized as a major economic bamboo species in China. So it is one of the most excellent economic bamboo species in south China and in the tropical and subtropical areas of the world. Based On the investigation of the biological characteristics and present seed resources situation of Dendrocalamus sinicus, the paper discusses the limitations of its natural population distribution, its fragile growth and propagation, and its rich meaning in culture. The authors suggest that this species be included in the list of wild plants for priority protection in China, nature reserve of Dendrocalamus sinicus (ecological and cultural) be established in its main distribution areas and that its scientific protection and industrial development be carried out as soon as possible.

Isolation and Structural Exploration of Hemicelluloses from the Largest Bamboo Species: Dendrocalamus sinicus

Dendrocalamus sinicus, which is the largest bamboo species in the world, has broad prospects for use in biomass-energy and biorefinery applications. In this study, five soluble hemicelluloses fractions were sequentially isolated with 80% ethanol (containing 0.025 M HCl or 0.5% NaOH), and alkaline aqueous solutions (containing 2.0, 5.0, or 8.0% NaOH) at 75 °C for 4 h from dewaxed D. sinicus, and their structural properties were examined. Gel permeation chromatography analysis revealed that the hemicelluloses isolated from D. sinicus had a wide distribution of molecular weights. The hemicelluloses isolated by ethanol had lower weight-average molecular weights (ranging from 17380 to 19620 g/mol), while the hemicelluloses isolated using alkaline aqueous solutions had higher weight-average molecular weights (ranging from 22510 to 42150 g/mol). Neutral sugar analysis indicated that the soluble hemicelluloses were mainly composed of arabinoglucuronoxylans, followed by minor amount of starch. Spectroscopic analyses suggested that the isolated arabinoglucuronoxylans from bamboo (D. sinicus) could be defined as a linear (1→4)-β-linked-xylopyranosyl backbone to which α-L-arabinofuranose and/or 4-O-methyl-glucuronic acid units were attached as single-unit side chains via α-(1→3) and/or α-(1→2) linkages.

Isolation and Structural Characterization of Lignin Polymer from Dendrocalamus sinicus

Dendrocalamus sinicus, which is the largest bamboo species in the world, has broad prospects in the fields of bioenergy and biorefinery application. In this study, dewaxed D. sinicus samples were sequentially treated with 80 % ethanol containing 0.025 M HCl, 80 % ethanol containing 0.5 % NaOH, and aqueous alkaline solutions (containing 2.0, 5.0, and 8.0 % NaOH, respectively) at 75 °C for 4 h, in which 9.63, 8.71, 21.83, 21.09, and 13.09 % of the original lignin were isolated, respectively. The lignin fractions obtained were comparatively characterized by chemical composition, molecular weights, and structural features by wet chemical and instrumental analysis methods. It was found that the bamboo lignin fractions isolated by ethanol had lower weight-average molecular weights (1,360–1,380 g mol−1) and contained much higher amounts of associated hemicelluloses, while the lignin fractions isolated by aqueous alkaline solutions had higher weight-average molecular weights (5,300–6,040 g mol−1) and contained lower amounts of associated hemicelluloses. Spectroscopy analyses indicated that the bamboo lignin was a typical grass lignin, consisting of p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S) units. A small percentage of the lignin side-chain was found to be acetylated at the γ-carbon, predominantly at syringyl units. The major interunit linkages present in the bamboo lignin obtained were β-O-4′ aryl ether linkages, together with lower amounts of β-β′, β-5′, and β-1′ linkages.

Sixteen novel microsatellite markers developed for Dendrocalamus sinicus (Poaceae), the strongest woody bamboo in the world

Microsatellite primers were developed in the strongest and most economically important bamboo species, Dendrocalamus sinicus, to investigate its genetic variability. Using the Fast Isolation by AFLP of Sequences COntaining Repeats (FIASCO) protocol, 16 polymorphic primer sets were identified within 24 individuals from two geographic locations. The number of alleles per locus ranged from two to four, with a mean of 2.6. The observed and expected heterozygosities varied from 0 to 1.000 and from 0.311 to 0.754, respectively. The cross-amplification of the 16 primer pairs was tested in four other Dendrocalamus species, and nine to 13 (56.3-81.3%) primer pairs were successfully amplified. These markers will be useful for studies on the genetic diversity of D. sinicus, which may facilitate conservation of this species.

Mining of SSR markers from Expressed Sequence Tags of bamboo species.

With the ever increasing number of Expressed Sequence Tags (ESTs) from various sequencing projects, ESTs have become valuable and first-hand source of in-silico mining of simple sequence repeats (SSR) markers. We examined a total of 3419 EST sequences from three bamboo species, namely, Phyllostachys edulis, Bambusa oldhamii and Dendrocalamus sinicus for the presence of di- to hexa- microsatellites. The frequency of SSR containing ESTs varied from 5.36% in B. oldhamii to 13.05% in P. edulis. No SSRs were found in D. sinicus. Tri-nucleotide repeats (49.34%) were most frequent in P. edulis, while not much comparable difference in repeats was found in B. oldhamii. Flanking primer pairs were also designed in-silico for the sequences containing SSRs and their position on the genome hypothesized using similarity searching. SSRs located in open reading frame (ORF) were given functional annotation using Gene Ontology. Polymorphic SSRs were also detected using new pipeline- polySSR. Polymorphism level was very low (2.43%) and the position of the polymorphic SSRs was determined. The development of SSRs and the study of polymorphism will help in the further study of intra- and inter- gene flow, genetic structure, variability, linkage mapping and evolutionary relationships in bamboo.