| 1. |
- Landberg, Tommy, et al.
(författare)
-
Differences in oxidative stress in heavy metal resistant and sensitive clones of Salix viminalis
- 2002
-
Ingår i: Journal of plant physiology (Print). - : Elsevier BV. - 0176-1617 .- 1618-1328. ; 159:1, s. 69-75
-
Tidskriftsartikel (refereegranskat)abstract
- Many stress mechanisms, such as antioxidative mechanisms, are known to be activated by heavy metals. The aim of this work was to investigate whether oxidative stress and related mechanisms were expressed differently in plants with different resistances to heavy metals. Different clones of Salix viminalis with different resistances to Cd, Cu, and Zn were cultivated hydroponically in the presence of 7 μmol/L Cd, 3 μmol/L Cu or 70 μmol/L Zn for 20 days. The clones were then compared with regard to the concentrations of free radicals, estimated by measuring thiobarbituric acid-reactive material (TBA-rm) and glutathione (GSH). The activity of the enzymes, aspartate peroxidase (APX), guaiacol peroxidase (GPX), superoxide dismutase (SOD), and catalase (CAT) was also analysed. Salicylic acid was also measured since it is known to be involved in antioxidative activities.The results showed that some differences could be observed between resistant and sensitive clones. The SOD activity was higher in untreated resistant clones compared with the sensitive ones. Under metal treatment, however, the SOD activity was similar. Furthermore, TBA-rm was higher in shoots of resistant clones compared to sensitive ones, while the opposite was found in roots.
|
|
| 2. |
- Mutisya, Joel, et al.
(författare)
-
Starch branching enzymes in sorghum (Sorghum bicolor) and barley (Hordeum vulgare) : Comparative analyses of enzyme structure and gene expression
- 2003
-
Ingår i: Journal of plant physiology (Print). - : Elsevier BV. - 0176-1617 .- 1618-1328. ; 160:8, s. 921-930
-
Tidskriftsartikel (refereegranskat)abstract
- Summary A genomic clone for starch branching enzyme (SBE) IIb was isolated from a sorghum bacterial artificial chromosome (BAC) library. The promoter and 5′ flanking sequence, the first four exons and introns as well as the last exon and the 3′ untranslated region were sequenced. The tentative transcription start site of sorghum sbeIIb was mapped based on alignment with the maize sbeIIb gene. The exon-intron structure of the 5′ portion of sorghum sbeIIb was similar to that of maize sbeIIb but differed from that of barley sbeIIb. Specifically, the intronic Bbl element involved in the endosperm specific expression of barley sbeIIb was lacking in the sorghum gene. A cDNA clone for sorghum sbeIIb was reverse PCR amplified and found to encode an 803 amino acids long protein. The amino acid sequence of sorghum SBEIIb was compared to that of sorghum SBEI and corresponding enzymes in barley. The overall identity in amino acid sequence was 54 percnt; in the central portion of the enzymes. A major difference between the SBEII and SBEI isoforms was a 67 amino acids-long C-terminal extension in the SBEIs. The spatial and temporal expression patterns of sorghum sbeIIb was determined and compared with those of the sorghum gene for SBEI and the barley genes for SBEIIB and SBEI. All four genes exhibited a seed specific expression. However, while barley sbeIIb and sbeI transcripts were detected exclusively in the endosperm, the sorghum genes were expressed also in the embryo. The activity of sorghum sbeIIb and sbeI exhibited a late onset, with a peak of transcription at around 22 days after pollination. This is similar to the pattern of barley sbeI but different from that of barley sbeIIb, which showed a peak of transcription at 12 days after pollination.
|
|
| 3. |
- Ekelund, Nils, 1956-
(författare)
-
The effects of UV-B radiation on dinoflagellates
- 1991
-
Ingår i: Journal of plant physiology (Print). - 0176-1617 .- 1618-1328. ; 138, s. 274-278
-
Tidskriftsartikel (refereegranskat)abstract
- Ultraviolet radiation, UV-B (280-320 nm), has harmful effects on marine phytoplankton. The presentexperiments were done to determine the effects of UV-B radiation on motility and growth of four marine motile dinoflagellates, Gyrodinium aureolum, Prorocentrum minimum, Heterocapsa triquetra and Scrippsiella trochoidea. The specific growth rate of the dinoflagellates showed an inhibition after 1 hour UV-B (1.5 kj m(su-2}day-1) daily during 1 week. The motility of H. triquetra showed a pronounced inhibition after 12 kJ m-2day-1, the motility of S. trochoidea did not show the same sensitivity to UV-B radiation. The photosynthetic inhibitor DCMU (10-5M) inhibited the motility of S. trochoidea but not the motility of H. triquetra. Action spectra (UV-B, 280-320 nm) for inhibition of motility of G. aureolum showed the maximum sensitivity at 280 and 290 nm.
|
|
| 4. |
- Ali, Muhammad Amjad, et al.
(författare)
-
Transcription factors WRKY11 and WRKY17 are involved in abiotic stress responses in Arabidopsis
- 2018
-
Ingår i: Journal of plant physiology (Print). - : Elsevier. - 0176-1617 .- 1618-1328. ; 226, s. 12-21
-
Tidskriftsartikel (refereegranskat)abstract
- Plant WRKY transcription factors play a vital role in abiotic stress tolerance and regulation of plant defense responses. This study examined AtWRKY11 and AtWRKY17 expression under ABA, salt, and osmotic stress at different developmental stages in Arabidopsis. We used reverse transcriptase PCR, quantitative real-time PCR, and promoter:GUS lines to analyze expression. Both genes were upregulated in response to abiotic stress. Next, we applied the same stressors to seedlings of T-DNA insertion wrky11 and 17 knock-out mutants (single and double). Under stress, the mutants exhibited slower germination and compromised root growth compared with the wild type. In most cases, double-mutant seedlings were more affected than single mutants. These results suggest that wrky11 and wrky17 are not strictly limited to plant defense responses but are also involved in conferring stress tolerance.
|
|
| 5. |
- Bargaz, Adnane, et al.
(författare)
-
Discrimination against N-15 among recombinant inbred lines of Phaseolus vulgaris L. contrasting in phosphorus use efficiency for nitrogen fixation
- 2014
-
Ingår i: Journal of Plant Physiology. - : Elsevier BV. - 0176-1617 .- 1618-1328. ; 171, s. 199-204
-
Tidskriftsartikel (refereegranskat)abstract
- Although isotopic discrimination processes during nitrogen (N) transformations influence the outcome of N-15 based quantification of N-2 fixation in legumes, little attention has been given to the effects of genotypic variability and environmental constraints such as phosphorus (P) deficiency, on discrimination against N-15 during N-2 fixation. In this study, six Phaseolus vulgaris recombinant inbred lines (RILs), i.e. RILs 115, 104,34 (P deficiency tolerant) and 147, 83, 70 (P deficiency sensitive), were inoculated with Rhizobium tropici CIAT899, and hydroaeroponically grown with P-sufficient (250 mu mol P plant(-1) week(-1)) versus P-deficient (75 mu mol P plant(-1) week(-1)) supply. Two harvests were done at 15 (before nodule functioning) and 42 (flowering stage) days after transplanting. Nodulation, plant biomass, P and N contents, and the ratios of N-15 over total N content (N-15/Nt) for shoots, roots and nodules were determined. The results showed lower N-15/Nt in shoots than in roots, both being much lower than in nodules. P deficiency caused a larger decrease in N-15/Nt in shoots (-0.18%) than in nodules (-0.11%) for all of the genotypes, and the decrease in shoots was greatest for RILs 34 (-0.33%) and 104 (-0.25%). Nodule N-15/Nt was significantly related to both the quantity of N-2 fixed (R-2= 0.96***) and the P content of nodules (R-2= 0.66*). We conclude that the discrimination against N-15 in the legume N-2-fixing symbiosis of common bean with R. tropici CIAT899 is affected by P nutrition and plant genotype, and that the N-15/Nt in nodules may be used to screen for genotypic variation in P use efficiency for N-2 fixation. (C) 2013 Elsevier GmbH. All rights reserved.
|
|
| 6. |
- Bargaz, Adnane
(författare)
-
Expression of a phosphate-starvation inducible fructose-1,6-bisphosphatase gene in common bean nodules correlates with phosphorus use efficiency
- 2016
-
Ingår i: Journal of Plant Physiology. - : Elsevier BV. - 0176-1617 .- 1618-1328. ; 205, s. 48-56
-
Tidskriftsartikel (refereegranskat)abstract
- While increased P-hydrolysing acid phosphatases (APase) activity in bean nodules is well documented under phosphorus (P) limitation, gene expression and subcellular localization patterns within the N-2-fixing nodule tissues are poorly understood. The aim of this research was to track the enzyme activity along with the intra-nodular localization of fructose-1,6-bisphosphatase (FBPase), and its contribution to P use efficiency (PUE) under symbiotic nitrogen fixation (SNF) in Phaseolus vulgaris. The FBPase transcript were localized in situ using RT-PCR and the protein activity was measured in nodules of two contrasting recombinant inbred lines (RILs) of P. vulgaris, namely RILs 115 (P-efficient) and 147 (P-inefficient), that were grown under sufficient versus deficient P supply. Under P-deficiency, higher FBPase transcript fluorescence was found in the inner cortex as compared to the infected zone of RIL115. In addition, both the specific FBPase and total APase enzyme activities significantly increased in both RILs, but to a more significant extent in RIL115 as compared to RIL147. Furthermore, the increased FBPase activity in nodules of RIL115 positively correlated with higher use efficiency of both the rhizobial symbiosis (23%) and P for SNF (14% calculated as the ratio of N-2 fixed per nodule total P content). It is concluded that the abundant tissue-specific localized FBPase transcript along with induced enzymatic activity provides evidence of a specific tolerance mechanism where N-2-fixing nodules overexpress under P-deficiency conditions. Such a mechanism would maximise the intra-nodular inorganic P fraction necessary to compensate for large amount of P needed during the SNF process. (C) 2016 Elsevier GmbH. All rights reserved.
|
|
| 7. |
- Bhalerao, Rishikesh P.
(författare)
-
Effect of the photoperiod on bud dormancy in Liriodendron chinense
- 2022
-
Ingår i: Journal of Plant Physiology. - : Elsevier BV. - 0176-1617 .- 1618-1328. ; 279
-
Tidskriftsartikel (refereegranskat)abstract
- Bud dormancy and its release are complex physiological phenomena in plants. The molecular mechanisms of bud dormancy in Liriodendron chinense are mainly unknown. Here, we studied bud dormancy and the related phys-iological and molecular phenomena in Liriodendron under long-day (LD) and short-day (SD). Bud burst was released faster under LD than under SD. Abscisic acid (ABA), superoxide dismutase (SOD), catalase (CAT), and glutathione reductase (GR) activities were increased significantly under LD in Liriodendron buds. In contrast, the contents of gibberellic acid (GA3), ascorbic acid (AsA), glutathione (GSH), malondialdehyde (MDA), and ascorbate peroxidase (APX) activity decreased under LD but increased under SD. Differentially expressed genes (DEGs) were up-regulated under LD and down-regulated under SD and these changes correspondingly promoted (LD) or repressed (SD) cell division and the number and/or size of cells in the bud. Transcriptomic analysis of Liriodendron buds under different photoperiods identified 187 DEGs enriched in several pathways such as flavonoid biosynthesis and phenylpropanoid biosynthesis, plant hormone and signal transduction, etc. that are associated with antioxidant enzymes, non-enzymatic antioxidants, and subsequently promote the growth of the buds. Our findings provide novel insights into regulating bud dormancy via flavonoid and phenylpropanoid biosynthesis, plant hormone and signal transduction pathways, and ABA content. These physiological and biochemical traits would help detect bud dormancy in plants.
|
|
| 8. |
|
|
| 9. |
- Chardon, Fabien, et al.
(författare)
-
Natural variation in the long-distance transport of nutrients and photoassimilates in response to N availability
- 2022
-
Ingår i: Journal of plant physiology (Print). - : Elsevier. - 0176-1617 .- 1618-1328. ; 273
-
Tidskriftsartikel (refereegranskat)abstract
- Phloem and xylem tissues are necessary for the allocation of nutrients and photoassimilates. However, how the long-distance transport of carbon (C) and nitrogen (N) is coordinated with the central metabolism is largely unknown. To better understand how the genetic and environmental factors influence C and N transport, we analysed the metabolite profiles of phloem exudates and xylem saps of five Arabidopsis thaliana accessions grown in low or non-limiting N supply. We observed that xylem saps were composed of 46 or 56% carbohydrates, 27 or 45% amino acids, and 5 or 13% organic acids in low or non-limiting N supply, respectively. In contrast, phloem exudates were composed of 76 or 86% carbohydrates, 7 or 18% amino acids, and 5 or 6% organic acids. Variation in N supply impacted amino acid, organic acid and sugar contents. When comparing low N and non-limiting N, the most striking differences were variations of glutamine, aspartate, and succinate abundance in the xylem saps and citrate and fumarate abundance in phloem exudates. In addition, we observed a substantial variation of metabolite content between genotypes, particularly under high N. The content of several organic acids, such as malate, citrate, fumarate, and succinate was affected by the genotype alone or by the interaction between genotype and N supply. This study confirmed that the response of the transport of nutrients in the phloem and the xylem to N availability is associated with the regulation of the central metabolism and could be an adaptive trait.
|
|
| 10. |
- Doan, Thuy, et al.
(författare)
-
Functional expression of five Arabidopsis fatty acyl-CoA reductase genes in Escherichia coli
- 2009
-
Ingår i: Journal of Plant Physiology. - : Elsevier BV. - 0176-1617 .- 1618-1328. ; 166:8, s. 787-796
-
Tidskriftsartikel (refereegranskat)abstract
- Very long chain primary alcohols are significant components in cuticle waxes of plants. Fatty acyl-CoA reductases (FARs) catalyze the formation of a fatty alcohol from an acyl-CoA. The Arabidopsis (Arabidopsis thaliana) genome contains eight genes homologous to FAR genes from jojoba (Simmondsia chinensis), silk moth, wheat and mouse. Expression of six Arabidopsis FAR homologs in Escherichia coli resulted in production of alcohols from endogenous E. coli fatty acids by five of these genes, confirming that they encode for FAR enzymes. Only a truncated splicing version of the sixth gene was found, and this gene yielded a protein with no FAR activity. The five functional FAR enzymes yielded distinctly different compositions of fatty alcohols when expressed in E. coli, indicating that the different enzymes may be involved in the production of different types of alcohols in plant cells. (C) 2008 Elsevier GmbH. All rights reserved.
|
|
