The chloroplast psbA gene coding for Q_B of the photosystem Ⅱ reaction center in higher plants is an important light-regulated gene, and the promoter region controlling the efficiency of its expression is in the upst...The chloroplast psbA gene coding for Q_B of the photosystem Ⅱ reaction center in higher plants is an important light-regulated gene, and the promoter region controlling the efficiency of its expression is in the upstream region from the 5’-ending. The promoter structure of this gene resembles those E. coli, having a "-10" box and a "-35" box, but between these two boxes, a consensus sequence resembling eukaryotic "TATA" box has been found recently in some plants.展开更多
Mutations of the first position T and the third position G in TTGACA, the ' - 35' element of sorghum psbA gene promoter, were induced using chemically synthesized 20 nt oligonucleotide primer. Three mutants we...Mutations of the first position T and the third position G in TTGACA, the ' - 35' element of sorghum psbA gene promoter, were induced using chemically synthesized 20 nt oligonucleotide primer. Three mutants were produced: ATTACA, GTGACA, and ATGACA. Then the protein binding affinity of the mutants and the wild type sorghum psbA gene promoter was tested in a spinach chloroplast protein extract system. Gel retardation assay of the展开更多
Comparative analysis reveals remarkable homology between the sequences of both psbA gene nucleotidesand the inferred amino acids of sorghum, a C4 plant, and those of rice, a C3 plant. The 5'-noncoding region of so...Comparative analysis reveals remarkable homology between the sequences of both psbA gene nucleotidesand the inferred amino acids of sorghum, a C4 plant, and those of rice, a C3 plant. The 5'-noncoding region of sorghum psbA gene contains the conservative promoter elements, ' - 35' element and ' - 10' element, like the prokaryote and the promoter element, TATA box, like the eukaryote. As compared with that of the rice, an extra sequence of 7 bp is found in the leader sequence of the mRNA in the former. Using an in vitro system, it has been demonstrated that protein factor exists in sorghum chloroplast protein extract which specifically binds to the 5'-noncoding region of psbA gene. Measurement of the expression of luciferase shows a 2-5 time greater reaction of the expression plasmids pALqs which contain leader region of sorghum psbA gene than that of the expression plasmids pALqr which contain leader region of rice psbA gene in E. coli.展开更多
Kochia (Kochia scoparia L. Schrad.), also known as tumbleweed, is an economically important annual C4 broadleaf weed found throughout the US Great Plains. Several herbicides with different modes of action are used in ...Kochia (Kochia scoparia L. Schrad.), also known as tumbleweed, is an economically important annual C4 broadleaf weed found throughout the US Great Plains. Several herbicides with different modes of action are used in the management of kochia. The effect of commonly used herbicides on the expression of their target site(s) and photosynthetic/chloroplastic genes is poorly understood in weed species, including kochia. The objective of this research was to characterize the expression profiles of herbicide target-site genes, KspsbA, KsALS, and KsEPSPS upon treatment with PSII- (e.g. atrazine), ALS- (e.g. chlorsulfuron), and EPSPS- (e.g. glyphosate)-inhibitors, respectively, in kochia. Furthermore, the expression of genes involved in photosynthesis (e.g. KsRubisco, KsCAB, and KsPPDK) was also determined in response to these herbicide treatments. KspsbA was strongly upregulated (>200-fold) 24 h after atrazine treatment. Transcript levels of the KsALS or KsEPSPS genes were 7 and 3-fold higher 24 h after chlorsulfuron or glyphosate treatment, respectively. KsRubisco, a Calvin cycle gene important for CO2 fixation, was upregulated 7 and 2.6-fold 8 and 24 h after glyphosate and chlorsulfuron treatments, whereas it downregulated 8 and 24 h after atrazine treatment. The transcript levels of KsPPDK remained unchanged after glyphosate treatment but increased 1.8-fold and decreased 2-fold at 24 h after chlorsulfuron and atrazine treatments, respectively. KsCAB remained unchanged after chlorsulfuron treatment, but was downregulated after glyphosate and atrazine treatments. The results show that herbicide treatments not only affect the respective target-site gene expression, but also influence the genes involved in the critical photosynthetic pathway.展开更多
基金This work was supported by the grant from the Chinese National High-Tech Project
文摘The chloroplast psbA gene coding for Q_B of the photosystem Ⅱ reaction center in higher plants is an important light-regulated gene, and the promoter region controlling the efficiency of its expression is in the upstream region from the 5’-ending. The promoter structure of this gene resembles those E. coli, having a "-10" box and a "-35" box, but between these two boxes, a consensus sequence resembling eukaryotic "TATA" box has been found recently in some plants.
文摘Mutations of the first position T and the third position G in TTGACA, the ' - 35' element of sorghum psbA gene promoter, were induced using chemically synthesized 20 nt oligonucleotide primer. Three mutants were produced: ATTACA, GTGACA, and ATGACA. Then the protein binding affinity of the mutants and the wild type sorghum psbA gene promoter was tested in a spinach chloroplast protein extract system. Gel retardation assay of the
基金Project supported by the Chinese National "863" and "973" Projects.
文摘Comparative analysis reveals remarkable homology between the sequences of both psbA gene nucleotidesand the inferred amino acids of sorghum, a C4 plant, and those of rice, a C3 plant. The 5'-noncoding region of sorghum psbA gene contains the conservative promoter elements, ' - 35' element and ' - 10' element, like the prokaryote and the promoter element, TATA box, like the eukaryote. As compared with that of the rice, an extra sequence of 7 bp is found in the leader sequence of the mRNA in the former. Using an in vitro system, it has been demonstrated that protein factor exists in sorghum chloroplast protein extract which specifically binds to the 5'-noncoding region of psbA gene. Measurement of the expression of luciferase shows a 2-5 time greater reaction of the expression plasmids pALqs which contain leader region of sorghum psbA gene than that of the expression plasmids pALqr which contain leader region of rice psbA gene in E. coli.
文摘Kochia (Kochia scoparia L. Schrad.), also known as tumbleweed, is an economically important annual C4 broadleaf weed found throughout the US Great Plains. Several herbicides with different modes of action are used in the management of kochia. The effect of commonly used herbicides on the expression of their target site(s) and photosynthetic/chloroplastic genes is poorly understood in weed species, including kochia. The objective of this research was to characterize the expression profiles of herbicide target-site genes, KspsbA, KsALS, and KsEPSPS upon treatment with PSII- (e.g. atrazine), ALS- (e.g. chlorsulfuron), and EPSPS- (e.g. glyphosate)-inhibitors, respectively, in kochia. Furthermore, the expression of genes involved in photosynthesis (e.g. KsRubisco, KsCAB, and KsPPDK) was also determined in response to these herbicide treatments. KspsbA was strongly upregulated (>200-fold) 24 h after atrazine treatment. Transcript levels of the KsALS or KsEPSPS genes were 7 and 3-fold higher 24 h after chlorsulfuron or glyphosate treatment, respectively. KsRubisco, a Calvin cycle gene important for CO2 fixation, was upregulated 7 and 2.6-fold 8 and 24 h after glyphosate and chlorsulfuron treatments, whereas it downregulated 8 and 24 h after atrazine treatment. The transcript levels of KsPPDK remained unchanged after glyphosate treatment but increased 1.8-fold and decreased 2-fold at 24 h after chlorsulfuron and atrazine treatments, respectively. KsCAB remained unchanged after chlorsulfuron treatment, but was downregulated after glyphosate and atrazine treatments. The results show that herbicide treatments not only affect the respective target-site gene expression, but also influence the genes involved in the critical photosynthetic pathway.
