Keji Jiang
Fudan University
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Publication
Featured researches published by Keji Jiang.
Applied Biochemistry and Microbiology | 2007
Xuanwei Zhou; Z. Wang; Keji Jiang; Yamin Wei; Juan Lin; Xinghuai Sun; Kexuan Tang
A total of 38 endophytic fungus strains were isolated from Taxus chinensis var. mairei by the aseptic technique. Genomic DNA was extracted from isolated endophytic fungi and subjected to polymerase chain reaction (PCR) analysis for the presence of the Taxus taxadiene synthase (TS) gene, a rate-limiting enzyme gene in the taxol biosynthetic pathway. Twelve out of 38 isolated endophytic fungus strains showed PCR positive for the ts gene. Subsequently, taxol and its related compounds were extracted from culture filtrates and mycelia of the PCR positive strains, separated by column chromatography, and analyzed by High Performance Liquid Chromatography and Mass Spectrum. The analysis result showed that 3 strains could produce taxol and its related compounds at the detectible level. This study indicates that molecular detection of the ts gene is an efficient method for primary screening of taxol or its related compound-producing endophytic fungi, which can improve prominently screening efficiency.
Planta | 2009
Keji Jiang; Yan Pi; Rong Hou; Lili Jiang; Xiaofen Sun; Kexuan Tang
Plant secondary metabolites are a wide variety of low-molecular weight compounds whose productions are often enhanced in response to both biotic and abiotic stresses. Many of the responses are mediated by a class of hormones, named as jasmonates. In jasmonate biosynthetic pathway of plants, allene oxide cyclase (AOC, EC 5.3.99.6) catalyzes the most crucial step. Here a heterologous AOC gene from Hyoscyamus niger L. (black henbane), named HnAOC (GenBank accession No. AY708383), was overexpressed in Nicotiana tabacum cv. Petit Havana to investigate the consequence on nicotine content. This study revealed that the transcription of HnAOC in tobacco resulted in overexpression of nicotine biosynthetic pathway genes and higher yield of nicotine, with the maximum of 4.8-fold over control. Therefore, it indicated that without the cost of extrinsic hormones, genetic manipulation of jasmonate biosynthetic pathway genes could be an alternative approach in metabolic engineering for the production of valuable secondary metabolites, which were induced by jasmonates.
Molecular Biology Reports | 2009
Keji Jiang; Yan Pi; Rong Hou; Hainian Zeng; Zhuoshi Huang; Zheng Zhang; Xiaofen Sun; Kexuan Tang
In jasmonate biosynthetic pathway, allene oxide synthase (AOS, EC 4.2.1.92), which is a cytochrome P450 (CYP74A), catalyzes the first committed step. We herein cloned a novel cDNA from Lonicera japonica Thunb., named LjAOS (GenBank accession: DQ303120), which was homologous to other AOSs. Southern blot analysis revealed that it was a multi-copy gene. Real-time quantitative PCR analysis showed that LjAOS mRNA accumulated most abundantly in alabastrums, in which the content of chlorogenic acid (CA, the major important active ingredient indicator) was previously proven to be the highest.
Molecular Biology | 2008
Keji Jiang; Zhihua Liao; Yan Pi; Zhuoshi Huang; Rong Hou; Ying Cao; Qing Wang; Xiaofen Sun; Kexuan Tang
Hyoscyamus niger L. is a medicinal plant which produces a class of jasmonate-responsive pharmaceutical secondary metabolites named tropane alkaloids. As a family of signaling phytohormones, jasmonates play significant roles in the biosynthesis of many plant secondary metabolites. In the jasmonate biosynthetic pathway of plants, allene oxide cyclase (AOC, EC 5.3.99.6) catalyzes the most important step. Here we cloned a cDNA from H. niger, named HnAOC (GenBank accession no.: AY708383), which was 1044 bp long, with a 747-bp open reading frame (ORF) encoding a polypeptide of 248 amino acid residues. Southern blot analysis indicated that it was a multicopy gene. RT-PCR analysis revealed that the expression of HnAOC was regulated by various stresses and elicitors, with methyl-jasmonate showing the most prominent inducement. The characterization of HnAOC would be helpful for improving the production of valuable secondary metabolites by regulating the biosynthesis of jasmonates.
Bioscience Reports | 2008
Yan Pi; Zhihua Liao; Keji Jiang; Beibei Huang; Zhongxiang Deng; Dongli Zhao; Hainian Zeng; Xiaofen Sun; Kexuan Tang
AOC (allene oxide cyclase; EC 5.3.99.6), an essential enzyme in jasmonic acid and its methyl ester biosynthesis, was cloned from Camptotheca acuminata (named as CaAOC), a native medicinal plant species in China. CaAOC had significant similarity at the amino-acid level with AOCs from other plant species. Comparison between the sequences of the full-length cDNA and genomic DNA of CaAOC revealed that the genomic DNA of CaAOC contained an 89-bp intron and a 240-bp intron. Southern-blot analysis indicated that CaAOC was a multiple-copy gene, and real-time quantitative PCR analysis showed that CaAOC was expressed constitutively in all organs tested, with the highest expression level in leaves. The results from treatment experiments using different signalling components, including methyl jasmonate, abscisic acid, salicylic acid and H(2)O(2), revealed that expression of CaAOC had a prominent diversity. Heavy metal (copper) significantly enhanced CaAOC expression, whereas wounding (induced by UV-B) was not so effective.
Russian Journal of Genetics | 2009
Keji Jiang; Yan Pi; Z. Huang; Rong Hou; Zh. Zhang; Juan Lin; Xinghuai Sun; Kexuan Tang
In the endeavor to enhance the production of pharmaceutically valuable tropane alkaloids including hyoscyamine and scopolamine in Hyoscyamus niger, methyl jasmonate (MeJA) showed significant stimulation both in tropane biosynthetic pathway enzymes activities and tropane alkaloids yields. Therefore it was speculated that genetic engineering of jasmonate biosynthetic pathway might enhance the endogenous jasmonates concentration, followed by stimulating the production of tropane alkaloids. Herein a full-length cDNA encoding allene oxide synthase (AOS, EC 4.2.1.92), the first committed step enzyme in jasmonate biosynthetic pathway was reported (named HnAOS, GenBank accession: EF532599). HnAOS was a novel member of the cytochrome P450 (CYP74A) subfamily. Real-time quantitative PCR analysis showed that HnAOS mRNA accumulated mainly in stems, and responded significantly to wounding or methyl jasmonate.
Journal of Biochemistry and Molecular Biology | 2007
Zhuoshi Huang; Keji Jiang; Yan Pi; Rong Hou; Zhihua Liao; Ying Cao; Xu Han; Qian Wang; Xiaofen Sun; Kexuan Tang
Biocell | 2010
Yan Pi; Keji Jiang; Rong Hou; Yifu Gong; Juan Lin; Xiaofen Sun; Kexuan Tang
Molecular Biotechnology | 2009
Yan Pi; Keji Jiang; Ying Cao; Qian Wang; Zhuoshi Huang; Le Li; Lingchuan Hu; Wei Li; Xiaofen Sun; Kexuan Tang
Journal of Biochemistry and Molecular Biology | 2008
Qian Wang; Yan Pi; Rong Hou; Keji Jiang; Zhuoshi Huang; Ming-shiun Hsieh; Xiaofen Sun; Kexuan Tang