| 1. |
- Abreha, Kibrom Berhe, et al.
(författare)
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Sorghum in dryland: morphological, physiological, and molecular responses of sorghum under drought stress
- 2022
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Ingår i: Planta. - : Springer Science and Business Media LLC. - 0032-0935 .- 1432-2048. ; 255
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Forskningsöversikt (refereegranskat)abstract
- Sorghum is an economically important and a staple food crop for over half a billion people in developing countries, mostly in arid and semi-arid regions where drought stress is a major limiting factor. Although sorghum is generally considered tolerant, drought stress still signifcantly hampers its productivity and nutritional quality across its major cultivation areas. Hence, understanding both the efects of the stress and plant response is indispensable for improving drought tolerance of the crop. This review aimed at enhancing our understanding and provide more insights on drought tolerance in sorghum as a contribution to the development of climate resilient sorghum cultivars. We summarized fndings on the efects of drought on the growth and development of sorghum including osmotic potential that impedes germination process and embryonic structures, photosynthetic rates, and imbalance in source-sink relations that in turn afect seed flling often manifested in the form of substantial reduction in grain yield and quality. Mechanisms of sorghum response to drought-stress involving morphological, physiological, and molecular alterations are presented. We highlighted the current understanding about the genetic basis of drought tolerance in sorghum, which is important for maximizing utilization of its germplasm for development of improved cultivars. Furthermore, we discussed interactions of drought with other abiotic stresses and biotic factors, which may increase the vulnerability of the crop or enhance its tolerance to drought stress. Based on the research reviewed in this article, it appears possible to develop locally adapted cultivars of sorghum that are drought tolerant and nutrient rich using modern plant breeding techniques.
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| 2. |
- Ahad, Abdul, et al.
(författare)
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Actin is bundled in activation-tagged tobacco mutants that tolerate aluminum
- 2007
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Ingår i: Planta. - New York : Springer. - 0032-0935 .- 1432-2048. ; 225:2, s. 451-468
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Tidskriftsartikel (refereegranskat)abstract
- A panel of aluminum-tolerant (AlRes) mutants was isolated by protoplast-based T-DNA activation tagging in the tobacco cultivar SR1. The mutants fell into two phenotypic classes: a minority of the mutants were fertile and developed similarly to the wild type (type I), the majority was male-sterile and grew as semi-dwarfs (type II). These traits, along with the aluminum tolerance, were inherited in a monogenic dominant manner. Both types of mutants were characterized by excessive bundling of actin microfilaments and by a strongly increased abundance of actin, a phenotype that could be partially phenocopied in the wild type by treatment with aluminum chloride. The actin bundles could be dissociated into finer strands by addition of exogenous auxin in both types of mutants. However, actin microfilaments and leaf expansion were sensitive to blockers of actin assembly in the wild type and in the mutants of type I, whereas they were more tolerant in the mutants of type II. The mutants of type II displayed a hypertrophic development of vasculature, manifest in form of supernumerary leaf veins and extended xylem layers in stems and petioles. Whereas mutants of type I were characterized by a normal, but aluminum-tolerant polar auxin-transport, auxin-transport was strongly promoted in the mutants of type II. The phenotype of these mutants is discussed in terms of reduced endocytosis leading, concomitantly with aluminum tolerance, to changes in polar auxin transport.
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| 3. |
- Arnerup Christiansson, Jenny, et al.
(författare)
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The primary module in Norway spruce defence signalling against H. annosum s.l. seems to be jasmonate-mediated signalling without antagonism of salicylate-mediated signalling
- 2013
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Ingår i: Planta. - : Springer Science and Business Media LLC. - 0032-0935 .- 1432-2048. ; 237, s. 1037-1045
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Tidskriftsartikel (refereegranskat)abstract
- A key tree species for the forest industry in Europe is Norway spruce [Picea abies (L.) Karst.]. One of its major diseases is stem and butt rot caused by Heterobasidion parviporum (Fr.) Niemelä & Korhonen, which causes extensive revenue losses every year. In this study, we investigated the parallel induction of Norway spruce genes presumably associated with salicylic acid- and jasmonic acid/ethylene-mediated signalling pathways previously observed in response to H. parviporum. Relative gene expression levels in bark samples of genes involved in the salicylic acid- and jasmonic acid/ethylene-mediated signalling pathways after wounding and inoculation with either the saprotrophic biocontrol fungus Phlebiopsis gigantea or with H. parviporum were analysed with quantitative PCR at the site of the wound and at two distal locations from the wound/inoculation site to evaluate their roles in the induced defence response to H. parviporum in Norway spruce. Treatment of Norway spruce seedlings with methylsalicylate, methyljasmonate and inhibitors of the jasmonic acid/ethylene signalling pathway, as well as the Phenylalanine ammonia lyase inhibitor 2-aminoindan-2-phosphonic acid were conducted to determine the responsiveness of genes characteristic of the different pathways to different hormonal stimuli. The data suggest that jasmonic acid-mediated signalling plays a central role in the induction of the genes analysed in this study irrespective of their responsiveness to salicylic acid. This may suggest that jasmonic acid-mediated signalling is the prioritized module in the Norway spruce defence signalling network against H. parviporum and that there seems to be no immediate antagonism between the modules in this interaction.
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| 4. |
- Arnqvist, Lisa, 1970-, et al.
(författare)
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Overexpression of CYP710A1 and CYP710A4 in transgenic Arabidopsis plants increases the level of stigmasterol at the expense of sitosterol
- 2008
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Ingår i: Planta. - : Springer Science and Business Media LLC. - 0032-0935 .- 1432-2048. ; 227:2, s. 309-317
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Tidskriftsartikel (refereegranskat)abstract
- Sitosterol and stigmasterol are major sterols in vascular plants. An altered stigmasterol:sitosterol ratio has been proposed to influence the properties of cell membranes, particularly in relation to various stresses, but biosynthesis of stigmasterol is poorly understood. Recently, however, Morikawa et al. (Plant Cell 18:1008–1022, 2006) showed in Arabidopsis thaliana that synthesis of stigmasterol and brassicasterol is catalyzed by two separate sterol C-22 desaturases, encoded by the genes CYP710A1 and CYP710A2, respectively. The proteins belong to a small cytochrome P450 subfamily having four members, denoted by CYP710A1-A4, and are related to the yeast sterol C-22 desaturase Erg5p acting in ergosterol synthesis. Here, we report on our parallel investigation of the Arabidopsis CYP710A family. To elucidate the function of CYP710A proteins, transgenic Arabidopsis plants were generated overexpressing CYP710A1 and CYP710A4. Compared to wild-type plants, both types of transformant displayed a normal phenotype, but contained increased levels of free stigmasterol and a concomitant decrease in the level of free sitosterol. CYP710A1 transformants also displayed higher levels of esterified forms of stigmasterol, cholesterol, 24-methylcholesterol and isofucosterol. The results confirm the findings of Morikawa et al. (Plant Cell 18:1008–1022, 2006) regarding the function of CYP710A1 in stigmasterol synthesis, and show that CYP710A4 also has this capacity. Furthermore, our results suggest that an increased stigmasterol level alone is sufficient to stimulate esterification of other major sterols.
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| 5. |
- Asari, Shashidar, et al.
(författare)
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Analysis of plant growth-promoting properties of Bacillus amyloliquefaciens UCMB5113 using Arabidopsis thaliana as host plant
- 2017
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Ingår i: Planta. - : Springer Science and Business Media LLC. - 0032-0935 .- 1432-2048. ; 245, s. 15-30
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Tidskriftsartikel (refereegranskat)abstract
- This study showed that Bacillus amyloliquefaciens UCMB5113 colonizing Arabidopsis roots changed root structure and promoted growth implying the usability of this strain as a novel tool to support sustainable crop production.Root architecture plays a crucial role for plants to ensure uptake of water, minerals and nutrients and to provide anchorage in the soil. The root is a dynamic structure with plastic growth and branching depending on the continuous integration of internal and environmental factors. The rhizosphere contains a complex microbiota, where some microbes can colonize plant roots and support growth and stress tolerance. Here, we report that the rhizobacterium Bacillus amyloliquefaciens subsp. plantarum UCMB5113 stimulated the growth of Arabidopsis thaliana Col-0 by increased lateral root outgrowth and elongation and root-hair formation, although primary root elongation was inhibited. In addition, the growth of the above ground tissues was stimulated by UCMB5113. Specific hormone reporter gene lines were tested which suggested a role for at least auxin and cytokinin signaling during rhizobacterial modulation of Arabidopsis root architecture. UCMB5113 produced cytokinins and indole-3-acetic acid, and the formation of the latter was stimulated by root exudates and tryptophan. The plant growth promotion effect by UCMB5113 did not appear to depend on jasmonic acid in contrast to the disease suppression effect in plants. UCMB5113 exudates inhibited primary root growth, while a semi-purified lipopeptide fraction did not and resulted in the overall growth promotion indicating an interplay of many different bacterial compounds that affect the root growth of the host plant. This study illustrates that beneficial microbes interact with plants in root development via classic and novel signals.
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| 6. |
- Bailey, S, et al.
(författare)
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Acclimation of Arabidopsis thaliana to the light environment : the existence of separate low light and high light responses
- 2001
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Ingår i: Planta. - 0032-0935 .- 1432-2048. ; 213:5, s. 794-801
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Tidskriftsartikel (refereegranskat)abstract
- The capacity for photosynthetic acclimation in Arabidopsis thaliana (L.) Heynh. cv. Landsberg erecta was assessed during growth over a broad range of irradiance. Discontinuities in the response to growth irradiance were revealed for the light- and CO2-saturated rate of photosynthesis (P-max) and the ratio of chlorophyll a to chlorophyll b (Chl a/b). Three separate phases in the response of P-max and Chl a/b to growth light were evident, with increases at low and high irradiance ranges and a plateau at intermediate irradiance. By measuring all chlorophyll-containing components of the thylakoid membrane that contribute to Chl alb we reveal that distinct strategies for growth at low and high irradiance underlie the discontinuous response. These strategies include, in addition to changes in the major light-harvesting complexes of photosystem II (LHCII) , large shifts in the amounts of both reaction centres as well as significant changes in the levels of minor LHCII and LHCI components.
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| 7. |
- Bargaz, Adnane
(författare)
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Localization of phytase transcripts in germinating seeds of the common bean (Phaseolus vulgaris L.)
- 2014
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Ingår i: Planta. - : Springer Science and Business Media LLC. - 0032-0935 .- 1432-2048. ; 240, s. 471-478
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Tidskriftsartikel (refereegranskat)abstract
- The work provides the first-time evidence of tissue-specific expression of a phytase gene in the germinating seeds of Phaseolus vulgaris.Phytase enzyme plays a major role in germinating seeds. It is also active during N-2 fixation within nodules of legumes. The effect of phosphorus (P) deficiency on phytase gene expression and localization in N-2-fixing root nodules has been recently studied in hydroaeroponic culture of Phaseolus vulgaris. In this study, phytase gene transcripts within the germinating seed tissues of the P-inefficient P. vulgaris recombinant inbred line RIL147 were in situ localized with a similar RT-PCR recipe as that used for nodules. Our results show that the phytase gene expression was mainly localized in the outer layers, vascular cells and parenchyma of germinating seeds whereas it was localized in the inner and middle cortex of nodules. Image analysis quantified higher fluorescence intensity of the phytase transcript signal in the seed embryo than in radicles, cotyledons or the nodule cortex. Furthermore, the phytase activity was 22-fold higher in cotyledons (43 nmol min(-1) g(-1) dry weight) than in nodules (2 nmol min(-1) g(-1) dry weight). The K (m) and V (m) values of phytase activity in cotyledons were also significantly higher than in nodules. Interestingly, the amplified sequence of cDNA phytase exhibited highest homology with the Glycine max purple acid phosphatase (NM_001289274) 90 % for germinating seed as compared to nodule phytase cDNA displaying 94 % homology with the Glycine max phytase (GQ422774.1). It is concluded that phytase enzymes are likely to vary from seeds to nodules and that phytase enzymes play key roles in the use of organic P or N-2 fixation, as it is well known for germination.
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| 8. |
- Bargaz, Adnane
(författare)
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Localization of the Bacillus subtilis beta-propeller phytase transcripts in nodulated roots of Phaseolus vulgaris supplied with phytate
- 2014
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Ingår i: Planta. - : Springer Science and Business Media LLC. - 0032-0935 .- 1432-2048. ; 239, s. 901-908
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Tidskriftsartikel (refereegranskat)abstract
- Soil organic phosphorus (Po) such as phytate, which comprises up to 80% of total Po, must be hydrolyzed by specific enzymes called phytases to be used by plants. In contrast to plants, bacteria, such as Bacillus subtilis, have the ability to use phytate as the sole source of P due to the excretion of a beta-propeller phytase (BPP). In order to assess whether the B. subtilis BPP could make P available from phytate for the benefit of a nodulated legume, the P-sensitive recombinant inbred line RIL147 of Phaseolus vulgaris was grown under hydroaeroponic conditions with either 12.5μM phytate (C6H18O24P6) or 75μmol Pi (K2HPO4), and inoculated with Rhizobium tropici CIAT899 alone, or co-inoculated with both B. subtilis DSM 10 and CIAT899. The in situ RT-PCR of BPP genes displayed the most intense fluorescent BPP signal on root tips. Some BPP signal was found inside the root cortex and the endorhizosphere of the root tip, suggesting endophytic bacteria expressing BPP. However, the co-inoculation with B. subtilis was associated with a decrease in plant P content, nodulation and the subsequent plant growth. Such a competitive effect of B. subtilis on P acquisition from phytate in symbiotic nitrogen fixation might be circumvented if the rate of inoculation were reasoned in order to avoid the inhibition of nodulation by excess B. subtilis proliferation. It is concluded that B. subtilis BPP gene is expressed in P. vulgaris rhizosphere.
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| 9. |
- Basso, Marcos Fernando, et al.
(författare)
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Overexpression of a soybean Globin (GmGlb1-1) gene reduces plant susceptibility to Meloidogyne incognita
- 2022
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Ingår i: Planta. - : SPRINGER. - 0032-0935 .- 1432-2048. ; 256:4
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Tidskriftsartikel (refereegranskat)abstract
- Non-symbiotic globin class #1 (Glb1) genes are expressed in different plant organs, have a high affinity for oxygen, and are related to nitric oxide (NO) turnover. Previous studies showed that soybean Glb1 genes are upregulated in soybean plants under flooding conditions. Herein, the GmGlb1-1 gene was identified in soybean as being upregulated in the nematode-resistant genotype PI595099 compared to the nematode-susceptible cultivar BRS133 during plant parasitism by Meloidogyne incognita. The Arabidopsis thaliana and Nicotiana tabacum transgenic lines overexpressing the GmGlb1-1 gene showed reduced susceptibility to M. incognita. Consistently, gall morphology data indicated that pJ2 nematodes that infected the transgenic lines showed developmental alterations and delayed parasitism progress. Although no significant changes in biomass and seed yield were detected, the transgenic lines showed an elongated, etiolation-like growth under well-irrigation, and also developed more axillary roots under flooding conditions. In addition, transgenic lines showed upregulation of some important genes involved in plant defense response to oxidative stress. In agreement, higher hydrogen peroxide accumulation and reduced activity of reactive oxygen species (ROS) detoxification enzymes were also observed in these transgenic lines. Thus, based on our data and previous studies, it was hypothesized that constitutive overexpression of the GmGlb1-1 gene can interfere in the dynamics of ROS production and NO scavenging, enhancing the acquired systemic acclimation to biotic and abiotic stresses, and improving the cellular homeostasis. Therefore, these collective data suggest that ectopic or nematode-induced overexpression, or enhanced expression of the GmGlb1-1 gene using CRISPR/dCas9 offers great potential for application in commercial soybean cultivars aiming to reduce plant susceptibility to M. incognita.
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| 10. |
- Bykova, Natalia V, et al.
(författare)
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Interaction between photorespiration and respiration in transgenic potato plants with antisense reduction in glycine decarboxylase.
- 2005
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Ingår i: Planta. - : Springer Science and Business Media LLC. - 0032-0935 .- 1432-2048. ; 222:1, s. 130-40
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Potato (Solanum tuberosum L. cv. Désirée) plants with an antisense reduction in the P-protein of the glycine decarboxylase complex (GDC) were used to study the interaction between respiration and photorespiration. Mitochondria isolated from transgenic plants had a decreased capacity for glycine oxidation and glycine accumulated in the leaves. Malate consumption increased in leaves of GDC deficient plants and the capacity for malate and NADH oxidation increased in isolated mitochondria. A lower level of alternative oxidase protein and decreased partitioning of electrons to the alternative pathway was found in these plants. The adenylate status was altered in protoplasts from transgenic plants, most notably the chloroplastic ATP/ADP ratio increased. The lower capacity for photorespiration in leaves of GDC deficient plants was compensated for by increased respiratory decarboxylations in the light. This is interpreted as a decreased light suppression of the tricarboxylic acid cycle in GDC deficient plants in comparison to wild-type plants. The results support the view that respiratory decarboxylations in the light are restricted at the level of the pyruvate dehydrogenase complex and/or isocitrate dehydrogenase and that this effect is likely to be mediated by mitochondrial photorespiratory products.
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