Cloning and Functional Analysis of HDR Gene from Ginkgo biloba L

[Objective] The aims were to obtain cloning of HDR gene from Ginkgo biloba.and study its function.[Method] The coding sequence of HDR gene was cloned from G.biloba by reversed transcription polymerase chain reaction,which was designated as GbHDR （GenBank accession No.：DQ364231）.The cDNA full-length of GbHDR is 1 827 bp containing a 1 425-bp open reading frame （ORF） encoding a 474-amino-acid polypeptide and constructed into the prokaryotic expression vector pTrcGbHDR.The β-carotene biosynthetic pathway in E.coli strain XL1-Blue was reconstructed by transforming with pAC-BETA.This engineered XL1-Blue was transformed with pTrcGbHDR.[Result] A 1 441 bp GbHDR was obtained containing a 1 425-bp ORF encoding a 474-amino-acid residues of protein,the predicted molecular weight was 53.2 kD,and predicted isoelectric point was 5.76.Functional complementation assay indicated that GbHDR could promote theβ-carotene accumulation in engineered XL1-Blue harboring pTrcGbHDR and pAC-BETA,and as a result,the engineered bacteria showed the brightly orange given by β-carotene.This suggested that GbHDR had the typical function of known HDR genes.[Conclusion] A engineered bacteria of E.coli which could highly accumulate β-carotene was obtained,which will provide candidate genes and targets for realizing β-carotene metabolic engineering.

Identification and functional characterization of the AGO1 ortholog in maize

Eukaryotic Argonaute proteins play primary roles in mi RNA and si RNA pathways that are essential for numerous developmental and biological processes. However, the functional roles of the four Zm AGO1 genes have not yet been characterized in maize（Zea mays L.）. In the present study, Zm AGO1 a was identified from four putative Zm AGO1 genes for further characterization. Complementation of the Arabidopsis ago1-27 mutant with Zm AGO1 a indicated that constitutive overexpression of Zm AGO1 a could restore the smaller rosette, serrated leaves, later flowering and maturation, lower seed set, and darker green leaves at late stages of the mutant to the wild-type phenotype. The expression profiles of Zm AGO1 a under five different abiotic stresses indicated that Zm AGO1 a shares expression patterns similar to those of Argonaute genes in rice, Arabidopsis, and wheat.Further, variation in Zm AGO1 a alleles among diverse maize germplasm that resulted in several amino acid changes revealed genetic diversity at this locus. The present data suggest that Zm AGO1 a might be an important AGO1 ortholog in maize. The results presented provide further insight into the function of ZmAGO1a.

Cloning,expression and function of phosphate transporter encoded gene in Oryza sativa L.

OsPT6:1,a phosphate transporter encoding gene from the leaf samples of Oryza sativa, was identified through PCR with specifically designed primers.The phylogenetic analysis and the conserved amino acid residue site detection suggested OsPT6:1 a possible high-affinity phosphate transporter encoding gene.In situ hybridization and RT-PCR demonstrated the expression of OsPT6:1 in both roots and leaves.The peak expression signal was observed in mesophyll cells under low phosphorus(P)induction.A homologous recombination study indicated that OsPT6:1 can enhance the Pi uptake efficiency of Pichia pastoris.At the meantime,the introduction of OsPT6:1 was able to complement the Pi uptake function of yeast cells with high-affinity phosphate transporters de- ficient.Those results substantiated our contention that OsPT6:1 encoded a high-affinity phosphate transporter of Oryza sativa.