Identification and expression pattern analysis of a Moso Bamboo LTR retrotransposon / 生物工程学报

To develop more active LTR retrotransposons in Phyllostachys edulis, a Ph. edulis LTR retrotransposon (Ph-LTR2) was identified, and the expression pattern of the transposon under stress was systematically analyzed. Ph-LTR2 transposon is 6 030 bp in length and belongs to the Reina subfamily in the Ty3-Gypsy family. With the similarity of 96.41% of both LTR sequences, the Ph-LTR2 transposon inserted the moso bamboo genome about 61.92 thousand years ago. There are 5 copies identified in the genome. The Ph-LTR2 transposon domain includes GAG (gag protein) protein domain, PR (Proteases) protein domain, RT (Reverse transcriptase) protein domain, RH (Ribonuclease H) protein domain, INT (Integrase) protein domain and CHR (Chromatin organization modifier) protein domain. The expression patterns of INT, RT and RH were detected by real-time quantitative PCR. The three domains were found to have specific expression patterns at different tissues of the bamboo. Under the conditions of low/high temperature, methylation inhibitors treatments, irradiation and high salt stress, transcription levels of the three domains of the Ph-LTR2 transposon increased with different degrees. Specifically, after treatment with low/high temperature and methylation inhibitors, the transcription level was up-regulated; after low dose radiation treatment and low concentration of salt solution treatment, the transcription level was also increased, but the expression level decreased with increasing dose of radiation and concentration of salt solution. These results indicate that the expression pattern of the Ph-LTR2 transposon responds to the changes of the external environment, but the exact mechanism is not yet known. The results of this study laid a certain theoretical foundation for the development of the genetic tool based on Ph-LTR2 transposons.

Genome-wide identification and expression analysis of gibberellin biosynthesis, metabolism and signaling family genes in Phyllostachys edulis / 生物工程学报

Gibberellin is an essential plant hormone that plays an important regulatory role throughout the life cycle of higher plants. A total of 23 genes involved in gibberellin action were identified from Phyllostachys edulis genome, including 8 GA20ox and 1 GA3ox genes involved in the gibberellin biosynthesis, 8 GA2ox genes involved in the metabolism of gibberellin, 2 GID1 genes involved in gibberellin perception, 2 GID2 genes and 2 DELLA genes involved in gibberellin signal transduction. Phylogenetic analysis of these genes from Arabidopsis, Oryza sativa and Phyllostachys edulis revealed that gibberellin biosynthesis, metabolism, and signaling pathways are conserved in these species. Treatment of seeds and seedlings of bamboo with exogenous gibberellin revealed that gibberellin significantly increased seed germination rate and stem elongation of seedlings, and had the best concentration of action. The expression levels of GA20ox and GA3ox genes in the bamboo seedlings were down-regulated and the expression of the active gibberellin-degrading gene GA2ox was up-regulated after GA3 treatment, and the transcriptional level of the gibberellin receptor GID1 and the positive regulatory gene GID2 was significantly increased while the expression of the negative regulatory gene DELLA was decreased. These genes have significant differences in the expression of different spatial locations of bamboo shoot stems, GA20ox, GA3ox, GA2ox, GID1 and GID2 are all expressed in the upper part of bamboo shoots, while the repressor gene DELLA accumulates at the bottom of the shoots and is hardly expressed at the top.

Expression, purification and characterization of 3-Deoxy-D-manno-octulosonate 8-phosphate synthase from Phyllostachys edulis / 生物工程学报

3-Deoxy-D-manno-octulosonate 8-phosphate synthase (KDO8PS) is the key enzyme to synthesize eight-carbon sugar in plant and gram-negative bacterial cell wall. To analyze the polymerization and characterization in plant KDO8PS, the candidate gene was cloned from fresh Phyllostachys edulis seedling by RT-PCR. The open reading frame of PeKDO8PS is 876 bp deduced into 291 amino acid residues. The target protein was overexpressed in Escherichia coli induced by IPTG and then lager amount of fusion protein was purified through two-step methods with affinity chromatography and size-exclusion chromatography (SEC). SEC analysis shows that PeKDO8PS protein existed mainly in the form of dime in solution. Glutaraldehyde cross-linking experiments confirmed that the enzyme could form dimers. Further we identified that KDO8PS at high concentration two dimers could form tetramer in aqueous solution by analytical ultracentrifuge (AUC) analysis. The pH of the catalytic reaction was between 4.0 and 9.0, the optimum pH value was 8, the thermal stability range was between 25 and 65 ℃, and the optimum temperature was about 55 ℃. The enzyme activity was inhibited by some metal ions at lower concentrations, especially in the presence of Fe3+metal ion and activated by metal protease inhibitor EDTA at low concentration.

Chemical constituents from shoots of Phyllostachys edulis (I) / 中草药

Objective: To investigate the chemical constituents from the shoots of Phyllostachys edulis. Methods: Compounds were isolated by using a combination of various chromatographic techniques including silica gel, ODS, Sephadex LH-20, reversed-phase HPLC, and others. And the structures were elucidated by the nuclear magnetic resonance (NMR), mass spectrometry, and other modern spectroscopy. Results: Eighteen compounds were isolated from the shoots of P. edulis and identified as thymidine (1), uracil (2), 5-ethyluracil (3), 4-hydroxy-3-methoxybenzoic acid (4), p-hydroxy-benzaldehyde (5), adenosine (6), uridine (7), 2'-O-methyluridine (8), ethyl-p-hydroxybenzoate (9), cyclo (L-Val-L-Ala) (10), cyclo (L-Phe-L-Leu) (11), flazine (12), ethyl 4-(sulfooxy) benzoate (13), 1H-indole-3-carboxylic acid, methyl ester (14), cis-p-hydroxyl ethyl cinnamate (15), trans-p-hydroxyl ethyl cinnamate (16), 4-hydroxy-2-methoxy-benzaldehyde (17), and methyl p-hydroxy benzeneacetate (18). Conclusion: All the compounds are isolated from the shoots of P. edulis for the first time, and compounds 6-18 are firstly obtained from the plants of Phyllostachys Sieb. et Zucc.