| 1. |
- Sävenstrand, Helena, et al.
(författare)
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A Pisum sativum glyoxysomal malate dehydrogenase induced by cadmium exposure
- 2004
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Ingår i: DNA Sequence. - : Informa UK Limited. - 1042-5179 .- 1029-2365. ; 15:3, s. 206-208
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Tidskriftsartikel (refereegranskat)abstract
- The glyoxysomal malate dehydrogenase (gMDH) catalyses the formation of oxaloacetate from malate during beta-oxidation of fatty acids in the glyoxysome. A partial Pisum sativum L. (cv. Greenfeast) cDNA was first isolated from a suppression subtractive hybridisation cDNA library obtained from heavy metal stressed plants. The full length cDNA was then isolated by rapid amplification of cDNA ends. The translated sequence showed strong similarity to Cucumis sativus and Citrullus lanatus gMDH including a typical glyoxysome-targeting presequence comprising the PTS2 motif and a cleavage site for a cystein-directed protease. Exposure of pea plants to Cd2+ induced expression of the gMDH gene in mature pea leaves indicating that the enzyme is under environmental control in addition to the normal developmental regulation pattern.
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| 2. |
- Sävenstrand, Helena, et al.
(författare)
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Induction of early light-inducible protein gene expression in Pisum sativum after exposure to low levels of UV-B irradiation and other environmental stresses
- 2004
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Ingår i: Plant Cell Reports. - : Springer Science and Business Media LLC. - 0721-7714 .- 1432-203X. ; 22:7, s. 532-536
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Tidskriftsartikel (refereegranskat)abstract
- Plants are constantly subjected to environmental changes and have developed various defence mechanisms to facilitate their continued existence. Pisum sativum plants were exposed to low levels of UV-B radiation and ELIP (early light-inducible proteins) mRNA, with a probable protective function, was rapidly and strongly induced during this type of stress. To our knowledge, this is the only photosynthetic gene that is up-regulated following exposure to UV-B, and this result has to be compared with studies predominantly reporting down-regulation by UV-B of genes encoding proteins localised in the plastid. The expression pattern of ELIP mRNA in pea was also investigated during salt, wounding and ozone stress. The transcript levels of ELIP were induced after the salt and wounding treatments but not during ozone fumigation.
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| 3. |
- Sävenstrand, Helena, et al.
(författare)
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Six genes strongly regulated by mercury in Pisum sativum roots
- 2004
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Ingår i: Plant physiology and biochemistry (Paris). - : Elsevier BV. - 0981-9428 .- 1873-2690. ; 42:2, s. 135-142
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Tidskriftsartikel (refereegranskat)abstract
- Suppression subtractive hybridisation was used to isolate heavy metal-induced genes from Pisum sativum roots hydroponically exposed to 5 microM HgCl2 and 10 microM EDTA. Six genes were induced out of which one, PsHMIP6B, was novel. The other genes (PsSAMT, PsI2'H, PsNDA, PsAPSR, PsPOD) had not previously been isolated from pea and sequenced. All six genes were also induced after exposure to 5 microM HgCl2 in the absence of EDTA. The induction pattern was in some cases different for the two Hg species, demonstrating a quicker response to-free Hg2+ than Hg-EDTA. The stress-specificity of the gene regulation was investigated by hydroponically adding 5 microM Cd2+. Most Hg-induced cDNAs were also induced by Cd2+ but to a smaller extent than after Hg exposure. In addition, the gene expression was also probed for tissue specificity, which showed that all six genes were expressed in roots and not in leaves.
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| 4. |
- Sävenstrand, Helena, et al.
(författare)
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Ultraviolet-B signalling : Arabidopsis brassinosteroid mutants are defective in UV-B regulated defence gene expression
- 2004
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Ingår i: Plant physiology and biochemistry (Paris). - : Elsevier BV. - 0981-9428 .- 1873-2690. ; 42:9, s. 687-694
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Tidskriftsartikel (refereegranskat)abstract
- The involvement of brassinosteroids in signalling events in plants during UV-B stress (280-315 nm) was investigated in Arabidopsis thaliana. Brassinosteroids are involved in growth and development in plants and have also been shown to enhance stress tolerance. Three mutants deficient in the biosynthetic pathway of brassinolide (BL; det2, dim1 and cpd) and the BL insensitive mutant (bri1) were together with visible light irradiated with 3 or 9 h of UV-B radiation (biologically effective radiation normalised to 300 nm being 0.24 W m(-2)). Also, a small size control, irx1, and Columbia 0 (Col-0) wild-type plants were examined under identical conditions. Gene expression patterns were established for these mutants with a set of four molecular markers (the defence genes chalcone synthase (CHS), PYROA, pathogenesis-related protein PR-5, and a gene regulated by very low levels of UV-B, MEB5.2). Although the genes in the brassinodefective mutants were still induced by UV-B radiation, they all also showed reduced levels of mRNA transcripts compared with Col-0 and irx1. The bri1 and cpd were the mutants with lowest levels of molecular marker mRNA transcripts. The effects of impairment of brassinosteroid signalling also differed between the genes studied, indicating a need for a complete brassinosteroid pathway in UV-B signalling.
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