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With genetic manipulation, five genes ( HPPD , VTE2 , VTE3 , VTE1 , and VTE4 ), which encode enzymes involved in tocopherol biosynthesis, were over-expressed in model plant Arabidopsis thaliana , either alone or in couple combinations ( VTE2 + VTE4 and VTE3 + VTE4 ), to value and compare the roles of enzymes played in tocopherol biosynthetic pathway under the same genetic background. Our results suggested that, elevated expression level of biosynthetic pathway gene affected either total tocopherol content or composition, it is recommended to choose two or more enzymes with different functions for genetic manipulation. It was also found that metabolic engineering of tocopherol biosynthetic pathway affected endogenous ascorbate and glutathione pools in leaves. Further study suggested that expression levels of genes encoding enzymes of Halliwell–Asada cycle were up-regulated, such as APX , DHAR and MDAR . These findings provide hints on the relationship of lipid-soluble antioxidant vitamin E and water-soluble antioxidants vitamin C and glutathione, which will help to perfect theory in plant physiology and give practical instruction for metabolic engineering.

The genomic DNA sequence of chalcone synthase (CHS) gene was cloned from Ginkgo biloba . The Gbchs was 1295 bp long and composed of two exons and one intron, one of the typical features of chalcone synthase genes. The genomic Southern blot analysis indicated that Gbchs belonged to a multigene family. RT-PCR analyses revealed that Gbchs expressed differentially in the root, stem and leaf tissues of G. biloba , and the expression was induced by UV-B and wounding treatments. The recombinant GbCHS protein was successfully expressed in Escherichia coli strain M15 [pREP4] with pQE30 vector and the result showed that the expressed GbCHS protein had molecular weight of about 42 kDa, a size matching that of the predicted by bioinformatic analysis. This study provides useful information for further studying this gene and its function in ginkgo flavonoids biosynthetic pathway in G. biloba , the so-called “living fossil” plant possessing many pharmaceutical properties for human health.

Bolting reduces the commercial value of Chinese cabbage, so inhibiting Chinese cabbage from bolting is important. Flowering locus C (FLC), a repressor of flowering, encodes a MADS-domain transcription factor in Arabidopsis thaliana. Here we report on the cloning and characterization of a FLC homologous gene from Chinese cabbage (designated as BrpFLC, GenBank accession number: AY364013) using RACE-PCR. The full-length cDNA of BrpFLC was 851 base pair (bp) and contained a 591 bp open reading frame (ORF) encoding a protein with 197 amino acid residues. The BrpFLC gene had a high degree of similarity to Brassica napus MADS-box protein mRNA (AY036890) and Brassica rapa cultivar samjin flowering locus C (FLC) mRNA (AY273162). Southern blot analysis indicated that the FLC gene belonged to a multi-gene family when the coding sequence of BrpFLC was used as a probe, and there was a single copy when a 3′ UTR region was used as a probe. Northern blot analysis using the 3′ UTR of BrpFLC as the probe revealed that the transcript level of BrpFLC of different anti-bolting Chinese cabbage cultivars was reduced by vernalization at different degrees, and the BrpFLC transcript levels of anti-bolting cultivars remained higher than those of easy bolting cultivars after vernalization, implying that the degree of vernalization sensitivity of the BrpFLC gene was related to the level of bolting of Chinese cabbage.

A novel ethylene responsive element binding factors (ERFs) gene, designated as GbERF, was isolated by suppression subtraction hybridization and cDNA library screening from Gossypium barbadense (sea-island cotton). The GbERF cDNA has a total length of 1399 bp with an open reading frame of 954 bp, encoding a predicted polypeptide of 318 amino acids with a molecular weight of 36.1 kDa and a calculated pI of 4.87. The putative polypeptide of GbERF has an ERF domain, which shares high identity with other reported ERF domains, while the whole nucleotide and amino acid sequences have low homology with those of ERF genes from other plant species. RNA blot revealed that GbERF was constitutively expressed in roots and leaves. The transcripts of GbERF accumulated highly and rapidly when G. barbadense plant was treated with exogenous ethylene and Verticillium dahliae infection, accumulated slightly in response to salt, cold, drought stresses and exogenous abscisic acid (ABA) treatment, but declined in response to water stress. These results indicate that the GbERF may play an important role in response to ethylene, ABA, environmental stresses and pathogen attack.

A full-length cDNA encoding taxadienol acetyl transferase (designated as TmTAT), that catalyzes the first acylation step in Taxol biosynthesis, was cloned from young leaves of Taxus x media by rapid amplification of cDNA ends (RACE). The full-length cDNA of TmTAT was 1459 bp and contained a 1317-bp open reading frame (ORF) encoding a protein of 439 amino acids. The deduced protein had a calculated molecular weight of about 49 kDa and an isoelectric point (pI) of 5.3, similar to acetyl transferases from Taxus cuspidata and Taxus chinensis. Sequence comparison analysis revealed that the TmTAT had high similarity with other members of plant transferase family. Phylogenetic tree analysis showed that TmTAT had close relationship with acetyl transferases from T. chinenisis and T. cuspidata. Tissue expression pattern analysis revealed that TmTAT expressed strongly in leaves, weak in stems and no expression could be detected in fruits, indicating that TmTAT was a tissue-specific gene.

A new lectin gene was cloned from Arisaema heterophyllum. The full-length cDNA of Arisaema heterophyllum agglutinin (AHA) was 1169 bp and contained a 777 bp open reading frame encoding a 258 amino acid protein. Homology analysis showed that AHA had high homology with many other mannose-binding lectins. Secondary and three-dimensional analyses showed that AHA had many common characters of mannose-binding lectin superfamily. Southern blot analysis of the genomic DNA revealed that aha belonged to a multigene family. Northern blot analysis demonstrated that aha constitutively expressed in various plant tissues including inflorescence, leaf and tuber, and highly expressed in the tuber.

We used particle bombardment to cotransform mature seed-derived rice callus (Oryza sativa L., ssp. japonica, cv. Eyi 105) with plasmids containing the linked marker genes gusA and hpt, and the ap1 gene encoding an amphipathic protein previously shown to delay the hypersensitive response induced in non-host plants by the pathogen Pseudomonas syringae pv. syringae (Pss). Thirty-two independent lines of transgenic rice plants were regenerated, and 27 of these lines carried all three transgenes as shown by molecular analysis. A bacterial blight inoculation test was carried out on ten lines. In each case, plants carrying the ap1 gene showed enhanced resistance to Xanthomonas oryzae pv. oryzae (Xoo) race 6 at various levels. This suggests the ap1 gene could be a useful candidate for genetic engineering strategies in rice to provide bacterial blight resistance.