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- Gustafsson, Petter, 1948-, et al.
(författare)
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STRUCTURE AND REGULATION OF PHOTOSYNTHESIS GENES IN PINUS-SYLVESTRIS (SCOTS PINE) AND PINUS-CONTORTA (LODGEPOLE PINE)
- 1991
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Ingår i: Forest Ecology and Management. - 0378-1127 .- 1872-7042. ; 43:3-4, s. 287-300
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Tidskriftsartikel (refereegranskat)abstract
- The structure and regulation of one nuclear and one chloroplast gene was studied in Pinus sylvestris (Scots pine) and Pinus contorta (lodgepole pine). cDNA copies of the nuclear located cab genes of Pinus sylvestris, coding for the light-harvesting chlorophyll a/b-binding proteins of photosystem II (LHC-II), were cloned. cab-II genes coding for both types of LHC-II polypeptides, Types 1 and 2, were found. An analysis of the DNA sequences of several different cab-II cDNAs shows that they have a high bias for the nucleotides G and C at the third base positions of the codons, making them more similar to monocot than to dicot genes. Two of the three genes were found to be located within CpG islands. The cab-II genes were found to be expressed in dark-grown seedlings in contrast to what has been found for most angiosperms. The chloroplast genomes of conifers were shown to lack the inverted repeat organization normally found in higher plants, mosses and green algae. The psbA gene, located in the chloroplast genome and coding for the D1 polypeptide in the reaction center of photosystem II, was found to be tandemly duplicated in P. contorta. Cloning and sequence analysis of the two psbA genes and the surrounding regions showed that the duplicated segment is 1.97 kb long and that it ends 19 bp downstream from the psbA stop codon. The corresponding locus of P. sylvestris, which lacks the duplication, was cloned and characterized. A comparison with P. contorta indicates how the duplication/insertion event has occurred. A comparison of third codon position between P. contorta psbA and that of other plants indicated an almost equidistant evolutionary relationship between P. contorta, spinach (or barley) and Marchantia polymorpha.
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| 4. |
- Jansson, Stefan, 1959-, et al.
(författare)
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EVOLUTIONARY CONSERVATION OF THE CHLOROPHYLL A/B-BINDING PROTEINS - CDNAS ENCODING TYPE-I, TYPE-II, AND TYPE-III LHC-I POLYPEPTIDES FROM THE GYMNOSPERM SCOTS PINE
- 1991
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Ingår i: Molecular General Genetics. - 0026-8925 .- 1432-1874. ; 229:1, s. 67-76
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Tidskriftsartikel (refereegranskat)abstract
- cDNAs encoding three different LHC I polypeptides (Type I, Type II and Type III) from the gymnosperm Scots pine (Pinus sylvestris L.) were isolated and sequenced. Comparisons of the deduced amino acid sequences with the corresponding tomato sequences showed that all three proteins were highly conserved although less so than the LHC II proteins. The similarities between mature Scots pine and tomato Types I, II and III LHC I proteins were 80%, 87% and 85%, respectively. Two of the five His residues that are found in AXXXH sequences, which have been identified as putative chlorophyll ligands in the Type I and Type II proteins, were not conserved. The same two regions of high homology between the different LHC proteins, which have been identified in tomato, were also found in the Scots pine proteins. Within the conserved regions, the Type I and Type II proteins had the highest similarity; however, the Type II and Type III proteins also showed a similarity in the central region. The results suggest that all flowering plants (gymnosperms and angiosperms) probably have the same set of LHC polypeptides. A new nomenclature for the genes encoding LHC polypeptides (formerly cab genes) is proposed. The names lha and lhb are suggested for genes encoding LHC I and LHC II proteins, respectively, analogous to the nomenclature for the genes encoding other photosynthetic proteins.
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| 5. |
- Jansson, Stefan, 1959-, et al.
(författare)
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LIGHT-INDUCED-CHANGES OF PHOTOSYSTEM-II ACTIVITY IN DARK-GROWN SCOTS PINE-SEEDLINGS
- 1992
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Ingår i: Physiologia Plantarum. - : Wiley. - 0031-9317 .- 1399-3054. ; 84:1, s. 6-12
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Tidskriftsartikel (refereegranskat)abstract
- Both chlorophyll a and b and polypeptides of the photosynthetic apparatus are found in gymnosperm seedlings germinated and grown in absolute darkness. The photosystem II (PSII) activity is, however, limited, probably due to an inactive oxygen evolving system. In the present study dark-grown seedlings of Scots pine (Pinus sylvestris I..) were transferred to light and changes in antenna size and the activation process of PSII were investigated using fluorescence measurements and quantitative western blotting. It was found that the activation process is rapid, requires very little light and that strong light inhibits the process. It takes place without any changes in the primary reactions of PSII. Furthermore, all polypeptides except the major light-harvesting chlorophyll alb-binding protein complex of PSII (LHCII) were present in dark-grown seedlings in amounts comparable to the light treated control. The dark-grown seedlings had the same LHCII polypeptide composition as light treated seedlings, and the LHCII present seemed to be fully connected to the reaction centre. The results indicate that activation of PSII in dark-grown conifer seedlings resembles the photoactivation process of angiosperms. This implies that the fundamental processes in the assembly of the photosystem II complex is the same in all plants, but that the regulation differs between different taxa.
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