9401
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Xiao X, Yang F, Zhang S, Korpelainen H, Li C. Physiological and proteomic responses of two contrasting Populus cathayana populations to drought stress. Physiol Plant 2009; 136:150-68. [PMID: 19453505 DOI: 10.1111/j.1399-3054.2009.01222.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The acclimation of plants to water deficit is the result of many different physiological and biochemical mechanisms. To gain a better understanding of drought stress acclimation and tolerance mechanisms in Populus cathayana Rehder, we carried out an integrated physiological and comparative proteomic analysis on the drought stress responses of two contrasting populations originating from wet and dry regions in western China. The plantlets were subjected to continuous drought stress by withholding soil water content at 25% of field capacity (FC) for 45 days, while the control treatments were kept at 100% FC. Drought stress significantly inhibited plant growth, decreased net photosynthetic rate and stomatal conductance of leaves, increased the relative electrolyte leakage and malondialdehyde (MDA) content, and, at the same time, accumulated soluble sugars and free proline in both populations tested. The population from the dry climate region exhibited stronger tolerance to drought stress compared with the wet climate population. The proteomic analyses resulted in the identification of 40 drought-responsive proteins. The functional categories of these proteins include the regulation of transcription and translation, photosynthesis, cytoskeleton, secondary metabolism, HSPs/chaperones, redox homeostasis and defense response. The results suggest that poplars' tolerance to drought stress relates to the control of reactive oxygen species (ROS) and to osmoprotective capacity. The differential regulation of some drought-responsive proteins, such as HSPs and the enzymes related to redox homeostasis and regulation of secondary metabolism, plays an important role in poplars' tolerance and acclimation to drought stress. In conclusion, acclimation to water deficit involves changes in cellular metabolism and the regulation of gene networks. The present study not only provides new insights into the mechanisms of acclimation and tolerance to drought stress in different poplar populations but also provides clues for improving poplars' drought tolerance through breeding or genetic engineering.
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Affiliation(s)
- Xiangwen Xiao
- Chengdu Institute of Biology, Chinese Academy of Sciences, P.O.Box 416, Chengdu 610041, China
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9402
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Zhou SX, Tian F, Zhu ZF, Fu YC, Wang XK, Sun CQ. Identification of quantitative trait loci controlling drought tolerance at seedling stage in Chinese Dongxiang common wild rice (Oryza rufipogon Griff.). ACTA ACUST UNITED AC 2009; 33:551-8. [PMID: 16800386 DOI: 10.1016/s0379-4172(06)60084-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Common wild rice (Oryza rufipogon Griff.) is the ancestor of cultivated rice (O. sativa L.), which has a greater genetic diversity and important traits that remain to be employed in cultivated rice. In this study, a set of introgression lines (BC4F5 and/or BC4F6) carrying various introgressed segments from common wild rice, collected from Dongxiang county, Jiangxi Province, China, in the background of an Indica (O. sativa L. ssp. indica) cultivar, Guichao 2, was used. A total of 12 drought-related quantitative trait loci (QTL) were identified by investigating drought tolerance of introgression lines under 30% PEG treatment at the young seedlings stage. Of these QTLs, the alleles of 4 QTLs on chromosome 2, 6 and 12 from Dongxiang common wild rice were responsible for increased drought tolerance of the introgression lines. In particular, a QTL qSDT12-2, near RM17 on chromosome 12, was consistently detected in different replications, and expressed stably under PEG stress throughout the study. It was also found that the QTLs located on different chromosomes might express at different stages.
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Affiliation(s)
- Shao-Xia Zhou
- State Key Laboratory of Agrobiotechnology, Department of Plant Genetics and Breeding, China Agricultural University, Beijing
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9403
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9404
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Abstract
The cuticles of plants provide a multifunctional interface between the plants and their environments. The cuticle, with its associated waxes, is a protective layer that minimizes water loss by transpiration and provides several functions, such as hydrophobicity, light reflection and absorption of harmful radiation. The self-healing of voids in the epicuticular wax layer has been studied in 17 living plants by atomic force microscopy (AFM), and the process of wax film formation is described. Two modes of wax film formation, a concentric layer formation and striped layer formation, were found, and the process of multilayer wax film formation is discussed. A new method for the preparation of small pieces of fresh, water-containing plant specimens for AFM investigations is introduced. The technique allows AFM investigations of several hours duration without significant shrinkage or lateral drift of the specimen. This research shows how plants refill voids in their surface wax layers by wax self-assembly and should be useful for the design of self-healing materials.
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Affiliation(s)
- Kerstin Koch
- Nees Institute for Biodiversity of Plants, Rheinische Friedrich-Wilhelms, University of Bonn, Meckenheimer Allee 170, 53115 Bonn, Germany.
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9405
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Abstract
BACKGROUND AND AIMS While pollinators may in general select for large, morphologically uniform floral phenotypes, drought stress has been proposed as a destabilizing force that may favour small flowers and/or promote floral variation within species. METHODS The general validity of this concept was checked by surveying a taxonomically diverse array of 38 insect-pollinated Mediterranean species. The interplay between fresh biomass investment, linear size and percentage corolla allocation was studied. Allometric relationships between traits were investigated by reduced major-axis regression, and qualitative correlates of floral variation explored using general linear-model MANOVA. KEY RESULTS Across species, flowers were perfectly isometrical with regard to corolla allocation (i.e. larger flowers were just scaled-up versions of smaller ones and vice versa). In contrast, linear size and biomass varied allometrically (i.e. there were shape variations, in addition to variations in size). Most floral variables correlated positively and significantly across species, except corolla allocation, which was largely determined by family membership and floral symmetry. On average, species with bilateral flowers allocated more to the corolla than those with radial flowers. Plant life-form was immaterial to all of the studied traits. Flower linear size variation was in general low among conspecifics (coefficients of variation around 10 %), whereas biomass was in general less uniform (e.g. 200-400 mg in Cistus salvifolius). Significant among-population differences were detected for all major quantitative floral traits. CONCLUSIONS Flower miniaturization can allow an improved use of reproductive resources under prevailingly stressful conditions. The hypothesis that flower size reflects a compromise between pollinator attraction, water requirements and allometric constraints among floral parts is discussed.
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9406
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Zhang Y, Su W, Zhang G. [Effect of water stress on content of active constituents in Erigeron breviscaps]. Zhongguo Zhong Yao Za Zhi 2009; 34:1191-1194. [PMID: 19673373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
OBJECTIVE To study the effect of water stress on the content of scutellarin and caffeate in Erigeron breviscaps. METHOD Fv/Fm, N content, as well as the content of scutellarin and caffeate under three water grads were measured. RESULT AND CONCLUSION Fv/Fm of the plant decreased significantly in 8% and 23% water treatment, that proved drought and waterlogging occurred. Under the two conditions, the contents of N were lower but the contents of active constituents were higher than those under 15% treatment. The results support the carbon-nutrient balance hypothesis and the "stress effect hypothesis" for the formation of geo-herbs.
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9407
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Kim C, Lemke C, Paterson AH. Functional dissection of drought-responsive gene expression patterns in Cynodon dactylon L. Plant Mol Biol 2009; 70:1-16. [PMID: 19152115 DOI: 10.1007/s11103-009-9453-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2008] [Accepted: 01/05/2009] [Indexed: 05/08/2023]
Abstract
Water deficit is one of the main abiotic factors that affect plant productivity in subtropical regions. To identify genes induced during the water stress response in Bermudagrass (Cynodon dactylon), cDNA macroarrays were used. The macroarray analysis identified 189 drought-responsive candidate genes from C. dactylon, of which 120 were up-regulated and 69 were down-regulated. The candidate genes were classified into seven groups by cluster analysis of expression levels across two intensities and three durations of imposed stress. Annotation using BLASTX suggested that up-regulated genes may be involved in proline biosynthesis, signal transduction pathways, protein repair systems, and removal of toxins, while down-regulated genes were mostly related to basic plant metabolism such as photosynthesis and glycolysis. The functional classification of gene ontology (GO) was consistent with the BLASTX results, also suggesting some crosstalk between abiotic and biotic stress. Comparative analysis of cis-regulatory elements from the candidate genes implicated specific elements in drought response in Bermudagrass. Although only a subset of genes was studied, Bermudagrass shared many drought-responsive genes and cis-regulatory elements with other botanical models, supporting a strategy of cross-taxon application of drought-responsive genes, regulatory cues, and physiological-genetic information.
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Affiliation(s)
- Changsoo Kim
- Plant Genome Mapping Laboratory, University of Georgia, 111 Riverbend Road, Athens, GA 30602, USA
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9408
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Guo Q, Zhang X, Shen X, Chen Y. [Effects of seed priming on drought tolerence in Prunella vulgaris]. Zhongguo Zhong Yao Za Zhi 2009; 34:1195-1198. [PMID: 19673374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
OBJECTIVE To explore an effective way to increase drought tolerance of Prunella vulgaris seed. METHOD The treatment of drought stress to P. vulgaris seeds was made by the different concentrations of PEG solutions. Primed seeds germinated under 25% PEG. RESULT As concentrations of PEG increasing, seed germination percentage, germination index and vitality index reduced. Primed with 20%-25% PEG, 300-500 mg x L(-1) GA3 and 1.6%-2.0% KNO3-KH2PO4 could enhance three population seeds germination index and vitality index under drought stress. Treated with NaCl, seeds germination percentage and germination index of two population increased, which came from Nanjing Zijinshan and Anhui Jinzhai, respectively, while those of seeds from Gansu Chengxian reduced. CONCLUSION Treated with PEG, GA3, KNO3-KH2 PO4 under proper concentration, seed vigor, seed resistance under drought stress would increase.
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Affiliation(s)
- Qiaosheng Guo
- Institute of Chinese Medicinal Materials, Nanjing Agricultural University, Nanjing 210095, China.
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9409
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Zhang Y, Tan J, Guo Z, Lu S, He S, Shu W, Zhou B. Increased abscisic acid levels in transgenic tobacco over-expressing 9 cis-epoxycarotenoid dioxygenase influence H2O2 and NO production and antioxidant defences. Plant Cell Environ 2009; 32:509-19. [PMID: 19183289 DOI: 10.1111/j.1365-3040.2009.01945.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Abscisic acid (ABA) regulates the plant's adaptive responses to abiotic stresses. Over-expression of the 9-cis-epoxycarotenoid dioxygenase gene (SgNCED1) in the transgenic tobaccos increased ABA content and tolerance to drought and salt stresses. H2O2 and nitric oxide (NO) contents were enhanced in guard cells and mesophyll cells of the transgenic plants, accompanied with increased transcripts and activities of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR). The enhancements of H2O2 and NO and transcripts and activities of antioxidant enzymes in the transgenic plants were blocked by pre-treatments with inhibitor of ABA biosynthesis, scavengers of H2O2 and NO, and inhibitors of NADPH oxidase and NO synthase-like (NOS-like). The elevated production of NO in the transgenic plants was blocked by scavenger of H2O2 and inhibitors of NADPH oxidase, whereas H2O2 level was not affected by scavenger of NO and inhibitor of NOS-like, indicating that H2O2 is essential for the elevated production of NO. The results demonstrate that the increased drought and salt tolerance in the transgenic plants is associated with ABA-induced production of H2O2 via NADPH oxidase and NO via NOS-like, which sequentially induce transcripts and activities of SOD, CAT, APX and GR.
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Affiliation(s)
- Yiming Zhang
- Biotechnology Laboratory for Forages and Turfgrass, College of Life Science, South China Agricultural University, Guangzhou, China
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9410
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Yang Z, Wu Y, Li Y, Ling HQ, Chu C. OsMT1a, a type 1 metallothionein, plays the pivotal role in zinc homeostasis and drought tolerance in rice. Plant Mol Biol 2009; 70:219-29. [PMID: 19229638 DOI: 10.1007/s11103-009-9466-1] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Accepted: 02/01/2009] [Indexed: 05/08/2023]
Abstract
Metallothioneins (MTs) are small, cysteine-rich, metal-binding proteins that may be involved in metal homeostasis and detoxification in both plants and animals. OsMT1a, encoding a type 1 metallothionein, was isolated via suppression subtractive hybridization from Brazilian upland rice (Oryza sativa L. cv. Iapar 9). Expression analysis revealed that OsMT1a predominantly expressed in the roots, and was induced by dehydration. Interestingly, the OsMT1a expression was also induced specifically by Zn(2+) treatment. Both transgenic plants and yeasts harboring OsMT1a accumulated more Zn(2+) than wild type controls, suggesting OsMT1a is most likely to be involved in zinc homeostasis. Transgenic rice plants overexpressing OsMT1a demonstrated enhanced tolerance to drought. The examination of antioxidant enzyme activities demonstrated that catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX) were significantly elevated in transgenic plants. Furthermore, the transcripts of several Zn(2+)-induced CCCH zinc finger transcription factors accumulated in OsMT1a transgenic plants, suggesting that OsMT1a not only participates directly in ROS scavenging pathway but also regulates expression of the zinc finger transcription factors via the alteration of Zn(2+) homeostasis, which leads to improved plant stress tolerance.
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Affiliation(s)
- Zhao Yang
- State Key Laboratory of Plant Genomics and National Centre for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, The Chinese Academy of Sciences, 100101, Beijing, China
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9411
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Bonhomme L, Monclus R, Vincent D, Carpin S, Claverol S, Lomenech AM, Labas V, Plomion C, Brignolas F, Morabito D. Genetic variation and drought response in two Populus x euramericana genotypes through 2-DE proteomic analysis of leaves from field and glasshouse cultivated plants. Phytochemistry 2009; 70:988-1002. [PMID: 19560791 DOI: 10.1016/j.phytochem.2009.05.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2009] [Revised: 05/15/2009] [Accepted: 05/20/2009] [Indexed: 05/09/2023]
Abstract
Genotype and water deficit effects on leaf 2-DE protein profiles of two Populus deltoides x Populus nigra, cv. 'Agathe_F' and 'Cima', were analysed over a short-term period of 18 days in glasshouse using 4-month-old rooted cuttings and over a long-lasting period of 86 days in open field using 4-year-old rooted cuttings. Leaf proteomes were analyzed using two-dimensional gel electrophoresis, and proteins were identified after database searching from MS peptide spectra. A reliable genotype effect was observed in the leaf proteome over experiment locations, water regimes and sampling dates. Quantitative differences between genotypes were found. Most of them corresponded to proteins matching isoforms or post-translational modification variants. However, 'Cima' displayed the highest abundance of antioxidant enzymes. In response to water deficit, about 10% of the reproducible spots significantly varied regardless of the experiment location, among which about 25% also displayed genotype-dependent variations. As a whole, while 'Cima' differed from 'Agathe_F' by increased abundance of enzymes involved in photorespiration and in oxidative stress, 'Agathe_F' was mainly differentiated by increased abundance of enzymes involved in photosynthesis.
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Affiliation(s)
- Ludovic Bonhomme
- Université d'Orléans, UFR-Faculté des Sciences, Laboratoire de Biologie des Ligneux et des Grandes Cultures, UPRES EA 1207, rue de Chartres, BP 6759, F-45067 Orléans Cedex 02, France
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9412
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Abstract
During the last years, our understanding of the mechanisms that control plant response to salt stress has been steadily progressing. Pharmacological studies have allowed the suggestion that the cytoskeleton may be involved in regulating such a response. Nevertheless, genetic evidence establishing that the cytoskeleton has a role in plant tolerance to salt stress has not been reported yet. Here, we have characterized Arabidopsis T-DNA mutants for genes encoding proteins orthologous to prefoldin (PFD) subunits 3 and 5 from yeast and mammals. In these organisms, PFD subunits, also known as Genes Involved in Microtubule biogenesis (GIM), form a heterohexameric PFD complex implicated in tubulin and actin folding. We show that, indeed, PFD3 and PFD5 can substitute for the loss of their yeast orthologs, as they are able to complement yeast gim2Delta and gim5Delta mutants, respectively. Our results indicate that pfd3 and pfd5 mutants have reduced levels of alpha- and beta-tubulin compared to the wild-type plants when growing under both control and salt-stress conditions. In addition, pfd3 and pfd5 mutants display alterations in their developmental patterns and microtubule organization, and, more importantly, are hypersensitive to high concentrations of NaCl but not of LiCl or mannitol. These results demonstrate that the cytoskeleton plays an essential role in plant tolerance to salt stress.
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Affiliation(s)
- Miguel A Rodríguez-Milla
- Departamento de Biología de Plantas, Centro de Investigaciones Biológicas-CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
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9413
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Gerosa G, Finco A, Mereu S, Vitale M, Manes F, Denti AB. Comparison of seasonal variations of ozone exposure and fluxes in a Mediterranean Holm oak forest between the exceptionally dry 2003 and the following year. Environ Pollut 2009; 157:1737-1744. [PMID: 18180087 DOI: 10.1016/j.envpol.2007.11.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2007] [Revised: 11/12/2007] [Accepted: 11/19/2007] [Indexed: 05/25/2023]
Abstract
Ozone and energy fluxes have been measured using the eddy covariance technique, from June to December 2004 in Castelporziano near Rome (Italy), and compared to similar measurements made in the previous year. The studied ecosystem consisted in a typical Mediterranean Holm oak forest. Stomatal fluxes have been calculated using the resistance analogy and by inverting the Penmann-Monteith equation. Results showed that the average stomatal contribution accounts for 42.6% of the total fluxes. Non-stomatal deposition proved to be enhanced by increasing leaf wetness and air humidity during the autumnal months. From a comparison of the two years, it can be inferred that water supply is the most important limiting factor for ozone uptake and that prolonged droughts alter significantly the stomatal conductance, even 2 months after the soil water content is replenished. Ozone exposure, expressed as AOT40, behaves similarly to the cumulated stomatal flux in dry conditions whereas a different behaviour for the two indices appears in wet autumnal conditions. A difference also occurs between the two years.
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Affiliation(s)
- Giacomo Gerosa
- Department of Mathematics and Physics, Catholic University of the Sacred Heart, Via Musei 41, 25121 Brescia, BS, Italy
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9414
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Eriksen S, Lind J. Adaptation as a political process: adjusting to drought and conflict in Kenya's drylands. Environ Manage 2009; 43:817-35. [PMID: 18726051 DOI: 10.1007/s00267-008-9189-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Revised: 06/03/2008] [Accepted: 07/12/2008] [Indexed: 05/10/2023]
Abstract
In this article, we argue that people's adjustments to multiple shocks and changes, such as conflict and drought, are intrinsically political processes that have uneven outcomes. Strengthening local adaptive capacity is a critical component of adapting to climate change. Based on fieldwork in two areas in Kenya, we investigate how people seek to access livelihood adjustment options and promote particular adaptation interests through forming social relations and political alliances to influence collective decision-making. First, we find that, in the face of drought and conflict, relations are formed among individuals, politicians, customary institutions, and government administration aimed at retaining or strengthening power bases in addition to securing material means of survival. Second, national economic and political structures and processes affect local adaptive capacity in fundamental ways, such as through the unequal allocation of resources across regions, development policy biased against pastoralism, and competition for elected political positions. Third, conflict is part and parcel of the adaptation process, not just an external factor inhibiting local adaptation strategies. Fourth, there are relative winners and losers of adaptation, but whether or not local adjustments to drought and conflict compound existing inequalities depends on power relations at multiple geographic scales that shape how conflicting interests are negotiated locally. Climate change adaptation policies are unlikely to be successful or minimize inequity unless the political dimensions of local adaptation are considered; however, existing power structures and conflicts of interests represent political obstacles to developing such policies.
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Affiliation(s)
- Siri Eriksen
- Department of Sociology and Human Geography, University of Oslo, P.O. Box 1096, Blindern, 0317, Oslo, Norway.
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9415
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Damour G, Vandame M, Urban L. Long-term drought results in a reversible decline in photosynthetic capacity in mango leaves, not just a decrease in stomatal conductance. Tree Physiol 2009; 29:675-684. [PMID: 19324697 DOI: 10.1093/treephys/tpp011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The negative effects of drought on plant growth, development of natural plant communities and crop productivity are well established, but some of the responses remain poorly characterized, particularly the effect of long-term drought on photosynthetic capacity. We hypothesized that long-term drought results in a decline in leaf photosynthetic capacity, and not just a decrease in diffusive conductance. To test this hypothesis, we studied the effect of drought, slowly developed over 3.5 months, in leaves of eight potted mango (Mangifera indica L.) trees. We found that photosynthesis was not only limited by stomatal closure, but was also downregulated as a consequence of a strong decrease in photosynthetic capacity assessed by the measurements of maximal net photosynthesis (A(max)) and the light-saturated rate of photosynthetic electron transport (J(max)). The rapid recovery of A(max) and J(max), after only 1 week of rewatering, the maintenance of a stable pool of leaf nitrogen throughout the trial, and the decrease in quantum efficiency of open centers of photosystem II, indicate that the photosynthetic machinery escaped photodamage in the drought-treated trees and was simply downregulated during drought. The hexose-to-sucrose ratio was higher in leaves from drought-treated trees than in control leaves, suggesting that photosynthetic capacity decreased as a consequence of sink limitation.
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Affiliation(s)
- Gaëlle Damour
- CIRAD Persyst-UR 77, Station de Bassin Plat, BP 180, 97455 Saint Pierre Cedex, La Réunion, France
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9416
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Zavalloni C, Gielen B, De Boeck HJ, Lemmens CMHM, Ceulemans R, Nijs I. Greater impact of extreme drought on photosynthesis of grasslands exposed to a warmer climate in spite of acclimation. Physiol Plant 2009; 136:57-72. [PMID: 19374719 DOI: 10.1111/j.1399-3054.2009.01214.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In view of the projected increase in the frequency of extreme events during this century, we investigated the impact of a drought extreme on leaf ecophysiological parameters and carbon isotope composition (delta(13)C) of grassland communities with species richness (S) of one, three or nine species. The communities, grown for 3 years at either ambient air temperatures (ambient T(air)) or ambient T(air) + 3 degrees C (elevated T(air)), were additionally subjected to an imposed drought by withholding water for 24 days. During the previous 3 years equal precipitation was applied in both temperature treatments, thus communities at elevated T(air) had experienced more frequent, mild droughts. However, it was unknown whether this resulted in a higher resistance for facing extreme droughts. At similar soil matric potentials stomatal conductance (g(s)) and transpiration (Tr) were higher at elevated than ambient T(air), indicating acclimation to lower soil water content. Despite the stomatal acclimation observed, plants in elevated T(air) showed a lower resistance to the drought extreme as indicated by their lower photosynthetic rate (A(max)), g(s) and Tr during the entire duration of the drought extreme. Lower values for A(max), Tr and g(s) were also recorded in species at S = 3 as compared with species at S = 1 for both temperature treatments, but no further differences with S = 9 suggesting that stress was not alleviated at higher S-levels. The discrimination of (13)C was poorly correlated with measurements of instantaneous leaf water-use efficiency (A(max)/Tr) and, with this time scale and sampling method, it was not possible to detect any potential change in plant water-use efficiency using leaf delta(13)C.
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Affiliation(s)
- Costanza Zavalloni
- Research Group of Plant and Vegetation Ecology, Department of Biology, University of Antwerp (Campus Drie Eiken), Universiteitsplein 1, BE-2610 Wilrijk, Belgium
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9417
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Lee SJ, Cho DI, Kang JY, Kim SY. An ARIA-interacting AP2 domain protein is a novel component of ABA signaling. Mol Cells 2009; 27:409-16. [PMID: 19390821 DOI: 10.1007/s10059-009-0058-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2008] [Revised: 01/20/2009] [Accepted: 01/21/2009] [Indexed: 11/28/2022] Open
Abstract
ADAP is an AP2-domain protein that interacts with ARIA, which, in turn, interacts with ABF2, a bZIP class transcription factor. ABF2 regulates various aspects of the abscisic acid (ABA) response by controlling the expression of a subset of ABA-responsive genes. Our expression analyses indicate that ADAP is expressed in roots, emerging young leaves, and flowers. We found that adap knockout mutant lines germinate more efficiently than wild-type plants and that the mutant seedlings grow faster. This suggests that ADAP is involved in the regulation of germination and seedling growth. Both germination and post-germination growth of the knockout mutants were partially insensitive to ABA, which indicates that ADAP is required for a full ABA response. The survival rates for mutants from which water was withheld were low compared with those for wild-type plants. The result shows that ADAP is necessary for the response to stress induced by water deprivation. Together, our data indicate that ADAP is a positive regulator of the ABA response and is also involved in regulating seedling growth. The role of ADAP is similar to that of ARIA, which is also a positive regulator of the ABA response. It appears that ADAP acts through the same ABA response pathway as ARIA.
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Affiliation(s)
- Sun-ji Lee
- Department of Molecular Biotechnology and Kumho Life Science Laboratory, College of Agriculture and Life Sciences, Chonnam National University, Gwangju, Korea
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9418
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Zheng B, Yang L, Mao C, Huang Y, Wu P. Comparison of QTLs for rice seedling morphology under different water supply conditions. J Genet Genomics 2009; 35:473-84. [PMID: 18721784 DOI: 10.1016/s1673-8527(08)60065-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2008] [Revised: 05/12/2008] [Accepted: 05/16/2008] [Indexed: 11/18/2022]
Abstract
The variation of seedling characteristics under different water supply conditions is strongly associated with drought resistance in rice (Oryza sativa L.) and a better elucidation of its genetics is helpful for improving rice drought resistance. Ninetysix doubled-haploid (DH) rice lines of an indica and japonica cross were grown in both flooding and upland conditions and QTLs for morphological traits at seedling stage were examined using 208 restriction fragment length polymorphism (RFLP) and 76 microsatellite (SSR) markers. A total of 32 putative QTLs were associated with the four seedling traits: average of three adventitious root lengths (ARL), shoot height (SH), shoot biomass (SW), and root to shoot dry weight ratio (RSR). Five QTLs detected were the same under control and upland conditions. The ratio between the mean value of the seedling trait under upland and flooding conditions was used for assessing drought tolerance. A total of six QTLs for drought tolerance were detected. Comparative analysis was performed for the QTLs detected in this case and those reported from two other populations with the same upland rice variety Azucena as parent. Several identical QTLs for seedling elongation across the three populations with the positive alleles from the upland rice Azucena were detected, which suggests that the alleles of Azucena might be involved in water stress-accelerated elongation of rice under different genetic backgrounds. Five cell wall-related candidate genes for OsEXP1, OsEXP2, OsEXP4, EXT, and EGase were mapped on the intervals carrying the QTLs for seedling traits.
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Affiliation(s)
- Bingsong Zheng
- School of Forestry & Biotechnology, Zhejiang Forestry University, Hangzhou 311300, China.
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9419
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Borland AM, Griffiths H, Hartwell J, Smith JAC. Exploiting the potential of plants with crassulacean acid metabolism for bioenergy production on marginal lands. J Exp Bot 2009; 60:2879-96. [PMID: 19395392 DOI: 10.1093/jxb/erp118] [Citation(s) in RCA: 154] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Crassulacean acid metabolism (CAM) is a photosynthetic adaptation that facilitates the uptake of CO(2) at night and thereby optimizes the water-use efficiency of carbon assimilation in plants growing in arid habitats. A number of CAM species have been exploited agronomically in marginal habitats, displaying annual above-ground productivities comparable with those of the most water-use efficient C(3) or C(4) crops but with only 20% of the water required for cultivation. Such attributes highlight the potential of CAM plants for carbon sequestration and as feed stocks for bioenergy production on marginal and degraded lands. This review highlights the metabolic and morphological features of CAM that contribute towards high biomass production in water-limited environments. The temporal separation of carboxylation processes that underpins CAM provides flexibility for modulating carbon gain over the day and night, and poses fundamental questions in terms of circadian control of metabolism, growth, and productivity. The advantages conferred by a high water-storage capacitance, which translate into an ability to buffer fluctuations in environmental water availability, must be traded against diffusive (stomatal plus internal) constraints imposed by succulent CAM tissues on CO(2) supply to the cellular sites of carbon assimilation. The practicalities for maximizing CAM biomass and carbon sequestration need to be informed by underlying molecular, physiological, and ecological processes. Recent progress in developing genetic models for CAM are outlined and discussed in light of the need to achieve a systems-level understanding that spans the molecular controls over the pathway through to the agronomic performance of CAM and provision of ecosystem services on marginal lands.
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Affiliation(s)
- Anne M Borland
- Institute for Research on the Environment and Sustainability, Newcastle University, Newcastle Upon Tyne NE1 7RU, UK.
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9420
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Guo YH, Yu YP, Wang D, Wu CA, Yang GD, Huang JG, Zheng CC. GhZFP1, a novel CCCH-type zinc finger protein from cotton, enhances salt stress tolerance and fungal disease resistance in transgenic tobacco by interacting with GZIRD21A and GZIPR5. New Phytol 2009; 183:62-75. [PMID: 19402879 DOI: 10.1111/j.1469-8137.2009.02838.x] [Citation(s) in RCA: 146] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
* Zinc finger proteins are a superfamily involved in many aspects of plant growth and development. However, CCCH-type zinc finger proteins involved in plant stress tolerance are poorly understood. * A cDNA clone designated Gossypium hirsutum zinc finger protein 1 (GhZFP1), which encodes a novel CCCH-type zinc finger protein, was isolated from a salt-induced cotton (G. hirsutum) cDNA library using differential hybridization screening and further studied in transgenic tobacco Nicotiana tabacum cv. NC89. Using yeast two-hybrid screening (Y2H), proteins GZIRD21A (GhZFP1 interacting and responsive to dehydration protein 21A) and GZIPR5 (GhZFP1 interacting and pathogenesis-related protein 5), which interacted with GhZFP1, were isolated. * GhZFP1 contains two typical zinc finger motifs (Cx8Cx5Cx3H and Cx5Cx4Cx3H), a putative nuclear export sequence (NES) and a potential nuclear localization signal (NLS). Transient expression analysis using a GhZFP1::GFP fusion gene in onion epidermal cells indicated a nuclear localization for GhZFP1. RNA blot analysis showed that the GhZFP1 transcript was induced by salt (NaCl), drought and salicylic acid (SA). The regions in GhZFP1 that interact with GZIRD21A and GZIPR5 were identified using truncation mutations. * Overexpression of GhZFP1 in transgenic tobacco enhanced tolerance to salt stress and resistance to Rhizoctonia solani. Therefore, it appears that GhZFP1 might be involved as an important regulator in plant responses to abiotic and biotic stresses.
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Affiliation(s)
- Ying-Hui Guo
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China
| | - Yue-Ping Yu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China
| | - Dong Wang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China
| | - Chang-Ai Wu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China
| | - Guo-Dong Yang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China
| | - Jin-Guang Huang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China
| | - Cheng-Chao Zheng
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China
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9421
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Jain D, Roy N, Chattopadhyay D. CaZF, a plant transcription factor functions through and parallel to HOG and calcineurin pathways in Saccharomyces cerevisiae to provide osmotolerance. PLoS One 2009; 4:e5154. [PMID: 19365545 PMCID: PMC2664467 DOI: 10.1371/journal.pone.0005154] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2009] [Accepted: 03/13/2009] [Indexed: 01/19/2023] Open
Abstract
Salt-sensitive yeast mutants were deployed to characterize a gene encoding a C2H2 zinc finger protein (CaZF) that is differentially expressed in a drought-tolerant variety of chickpea (Cicer arietinum) and provides salinity-tolerance in transgenic tobacco. In Saccharomyces cerevisiae most of the cellular responses to hyper-osmotic stress is regulated by two interconnected pathways involving high osmolarity glycerol mitogen-activated protein kinase (Hog1p) and Calcineurin (CAN), a Ca(2+)/calmodulin-regulated protein phosphatase 2B. In this study, we report that heterologous expression of CaZF provides osmotolerance in S. cerevisiae through Hog1p and Calcineurin dependent as well as independent pathways. CaZF partially suppresses salt-hypersensitive phenotypes of hog1, can and hog1can mutants and in conjunction, stimulates HOG and CAN pathway genes with subsequent accumulation of glycerol in absence of Hog1p and CAN. CaZF directly binds to stress response element (STRE) to activate STRE-containing promoter in yeast. Transactivation and salt tolerance assays of CaZF deletion mutants showed that other than the transactivation domain a C-terminal domain composed of acidic and basic amino acids is also required for its function. Altogether, results from this study suggests that CaZF is a potential plant salt-tolerance determinant and also provide evidence that in budding yeast expression of HOG and CAN pathway genes can be stimulated in absence of their regulatory enzymes to provide osmotolerance.
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Affiliation(s)
- Deepti Jain
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, India
| | - Nilanjan Roy
- National Institute for Pharmaceutical Education and Research, SAS Nagar, Punjab, India
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9422
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Wilson PB, Estavillo GM, Field KJ, Pornsiriwong W, Carroll AJ, Howell KA, Woo NS, Lake JA, Smith SM, Harvey Millar A, von Caemmerer S, Pogson BJ. The nucleotidase/phosphatase SAL1 is a negative regulator of drought tolerance in Arabidopsis. Plant J 2009; 58:299-317. [PMID: 19170934 DOI: 10.1111/j.1365-313x.2008.03780.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
An Arabidopsis thaliana drought-tolerant mutant, altered expression of APX2 (alx8), has constitutively increased abscisic acid (ABA) content, increased expression of genes responsive to high light stress and is reported to be drought tolerant. We have identified alx8 as a mutation in SAL1, an enzyme that can dephosphorylate dinucleotide phosphates or inositol phosphates. Previously identified mutations in SAL1, including fiery (fry1-1), were reported as being more sensitive to drought imposed by detachment of rosettes. Here we demonstrate that alx8, fry1-1 and a T-DNA insertional knockout allele all have markedly increased resistance to drought when water is withheld from soil-grown intact plants. Microarray analysis revealed constitutively altered expression of more than 1800 genes in both alx8 and fry1-1. The up-regulated genes included some characterized stress response genes, but few are inducible by ABA. Metabolomic analysis revealed that both mutants exhibit a similar, dramatic reprogramming of metabolism, including increased levels of the polyamine putrescine implicated in stress tolerance, and the accumulation of a number of unknown, potential osmoprotectant carbohydrate derivatives. Under well-watered conditions, there was no substantial difference between alx8 and Col-0 in biomass at maturity; plant water use efficiency (WUE) as measured by carbon isotope discrimination; or stomatal index, morphology or aperture. Thus, SAL1 acts as a negative regulator of predominantly ABA-independent and also ABA-dependent stress response pathways, such that its inactivation results in altered osmoprotectants, higher leaf relative water content and maintenance of viable tissues during prolonged water stress.
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Affiliation(s)
- Pip B Wilson
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Biochemistry and Molecular Biology, The Australian National University, Canberra, ACT 0200, Australia
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9423
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Raju GS, Reddy YV, Babu KR. Hydrogeological aspects of Rajampet--a drought prone taluk, Kadapa district, Andhra Pradesh (India). J Environ Sci Eng 2009; 51:97-102. [PMID: 21114161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Rajampet taluk is semi-arid and drought prone situated in Kadapa district in Rayalaseema, Andhra Pradesh, was selected to conduct groundwater investigations. The study area was investigated in terms of its geology, hydrogeology, geoelectrical, aquifer parameters and quality of water. The groundwater samples from the wells of Rajampet taluk were collected and the chemical analysis for various parameters has been carried out. The data pertaining to water quality has been systematically processed and the results are presented numerically and graphically in this paper. 54 VES were carried out throughout the taluk. Pump test has been carried out in selected bore wells in the study area.
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Affiliation(s)
- G Sudarsana Raju
- Department of Geoinformatics, Yogi Vemana University, Kadapa, Andhra Pradesh - 516 003
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9424
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Elsdon TS, De Bruin MBNA, Diepen NJ, Gillanders BM. Extensive drought negates human influence on nutrients and water quality in estuaries. Sci Total Environ 2009; 407:3033-3043. [PMID: 19215967 DOI: 10.1016/j.scitotenv.2009.01.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2008] [Revised: 12/16/2008] [Accepted: 01/09/2009] [Indexed: 05/27/2023]
Abstract
Impacts of land-use on estuarine environmental parameters and nutrients are well documented, but little is known about these characteristics during extensive periods of low water flow (i.e., drought). Droughts are set to increase in frequency and magnitude with climate change, and understanding their influence on ecosystems is imperative. We investigated differences in environmental parameters and nutrients in urban and rural estuaries during a period of prolonged low flow. Sampling was done along each estuary at multiple times to place small-scale variability in the context of land-use differences. No differences were detected between land-use for environmental parameters or nutrients in mean effects or variance structure. Urban estuaries had reduced variation in nutrients over time compared to rural estuaries, which suggested that their concentrations are more stable. Large differences existed within and between individual estuaries, and over time. Low freshwater flow conditions in estuaries provide a glimpse to future climate change impacts of drought, and a baseline upon which pollution and anthropogenic effects can be assessed.
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Affiliation(s)
- Travis S Elsdon
- Southern Seas Ecology Laboratories, School of Earth and Environmental Sciences, Darling Building DX 650 418, University of Adelaide, Adelaide, South Australia 5005, Australia.
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9425
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Caldwell K, Boyd CP. Coping and resilience in farming families affected by drought. Rural Remote Health 2009; 9:1088. [PMID: 19415964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023] Open
Abstract
OBJECTIVES The present study was a qualitative investigation of the impact of drought on rural families of southern New South Wales, Australia, with particular emphasis on the concept of resilience in times of stress. The aim was to provide insight, from a psychological perspective, into the experiences of rural farmers in a time of adversity, and to identify the coping resources utilized by these farming families. METHOD Participants were 11 members of five families from Blighty, a small farming town in the Riverina district, experiencing drought and decreased water allocation to their local area. Family members were interviewed on two separate occasions at their farms. RESULTS Analysis of interview transcripts revealed that a wide range of coping strategies were being utilized by these families from problem-focussed coping, optimism and positive appraisal to less adaptive strategies such as cognitive dissonance, denial and avoidance of negative social influences. A significant finding was the discovery of a range of collective coping strategies used by the families in this study and the reliance on social capital as an adaptive resource. There were signs, however, that social cohesion of this community had become compromised due to competition for resources. CONCLUSION The adaptive coping mechanisms traditionally employed by these farming families are starting to weaken and urgent work to enhance the individual coping strategies of farmers is needed. Furthermore, Government needs to recognise the importance of social capital as a coping resource that will enable farming families to adapt and survive drought conditions into the future. Providing financial assistance to support current community initiatives and collective coping strategies may prove more beneficial to farmers than allocating inadequate amounts of funding to individual farming families.
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Affiliation(s)
- Kirra Caldwell
- Rural Adolescent Mental Health Group, Centre for Health Research and Practice, University of Ballarat, Ballarat, Victoria, Australia.
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9426
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Abstract
Droughts are common recurring natural hazards in Asia, and El Niño events are particularly severe in the Philippines. This paper explores responses by farm households, irrigation system managers, and macro policymakers in the Philippines to El Niño. In response to the large 1997-98 El Niño, farmers in one major irrigation system significantly diversified their economic activities, hut the drought was so acute that many of these activities were not successful. Communication between meteorologists and irrigation system managers is strong, and irrigation system managers are aware of El Niño events in advance. Communication between irrigation system managers and farmer irrigation associations is also strong, and together they have developed response options that attempt to augment supplies of and more efficiently allocate scarce water. Water pricing is not used, however, and lack of cooperation among farmers results in sub-optimal outcomes. Macro-level policy responses in terms of rice imports and buffer stock management to protect poor consumers have improved substantially over time.
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Affiliation(s)
- David Dawe
- Agricultural and Development Economics Division, Food and Agriculture Organization of the United Nations (FAO), Rome, Italy.
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9427
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Cao YJ, Wei Q, Liao Y, Song HL, Li X, Xiang CB, Kuai BK. Ectopic overexpression of AtHDG11 in tall fescue resulted in enhanced tolerance to drought and salt stress. Plant Cell Rep 2009; 28:579-88. [PMID: 19132376 DOI: 10.1007/s00299-008-0659-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2008] [Revised: 09/16/2008] [Accepted: 12/02/2008] [Indexed: 05/09/2023]
Abstract
Tall fescue (Festuca arundinacea Schreb.) is a cool-season perennial grass, which has been conventionally grown in the temperate area. However, as a major type of cool-season turf grass, its growth has been extended to the sub-tropical climate or even to the transitional climate between the sub-tropical and the tropical, and, in some cases, to heavily salinized lands. The extended growth imposes a serious challenge to its tolerance to the abiotic stress, particularly to drought, salt and high temperature. Here, we report a successful introduction of Arabidopsis AtHDG11 into the tall fescue via Agrobacterium-mediated transformation. The ectopic overexpression of AtHDG11 under the control of CaMV 35S promoter with four enhancers resulted in significantly enhanced tolerance to drought and salt stress. No obvious adverse effects on growth and development were observed in the transgenic plants. The enhanced stress tolerance was associated with a more extensive root system, a lower level of malondialdehyde, a nearly normal Na(+)/K(+) ratio, a higher level of proline and a kinetically accelerated induction of SOD and CAT activities observed in the transgenic plants during drought and/or salt stress, indicating that an enhanced ROS scavenging capability might play a significant role in the acquired tolerance to the abiotic stress.
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Affiliation(s)
- Ya-Jun Cao
- State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, China
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9428
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Brunner I, Pannatier EG, Frey B, Rigling A, Landolt W, Zimmermann S, Dobbertin M. Morphological and physiological responses of Scots pine fine roots to water supply in a dry climatic region in Switzerland. Tree Physiol 2009; 29:541-50. [PMID: 19203972 DOI: 10.1093/treephys/tpn046] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
In recent decades, Scots pine (Pinus sylvestris L.) forests in inner-Alpine dry valleys of Switzerland have suffered from drought and elevated temperatures, resulting in a higher mortality rate of trees than the mean mortality rate in Switzerland. We investigated the responses of fine roots (standing crop, morphological and physiological features) to water supply in a Scots pine forest in the Rhone valley. Before irrigation started in 2003, low- and high-productivity Scots pine trees were selected based on their crown transparency. The fine root standing crop measured in spring from 2003 to 2005 was unaffected by the irrigation treatment. However, irrigation significantly enhanced the fine root standing crop during the vegetation period when values from spring were compared with values from fall in 2005. Irrigation slightly increased specific root length but decreased root tissue density. Fine root O2-consumption capacity decreased slightly in response to the irrigation treatment. Using ingrowth cores to observe the responses of newly produced fine roots, irrigation had a significantly positive effect on the length of fine roots, but there were no differences between the low- and high-productivity trees. In contrast to the weak response of fine roots to irrigation, the aboveground parts responded positively to irrigation with more dense crowns. The lack of a marked response of the fine root biomass to irrigation in the low- and high-productivity trees suggests that fine roots have a high priority for within-tree carbon allocation.
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Affiliation(s)
- Ivano Brunner
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, CH-8903 Birmensdorf, Switzerland.
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9429
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Perry GLW, Bond NR. Spatially explicit modeling of habitat dynamics and fish population persistence in an intermittent lowland stream. Ecol Appl 2009; 19:731-746. [PMID: 19425435 DOI: 10.1890/08-0651.1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In temperate and arid climate zones many streams and rivers flow intermittently, seasonally contracting to a sequence of isolated pools or waterholes over the dry period, before reconnecting in the wetter parts of the year. This seasonal drying process is central to our understanding of the population dynamics of aquatic organisms such as fish and invertebrates in these systems. However, there is a dearth of empirical data on the temporal dynamics of such populations. We describe a spatially explicit individual-based model (SEIBM) of fish population dynamics in such systems, which we use to explore the long-term population viability of the carp gudgeon Hypseleotris spp. in a lowland stream in southeastern Australia. We explicitly consider the impacts of interannual variability in stream flow, for example, due to drought, on habitat availability and hence population persistence. Our results support observations that these populations are naturally highly variable, with simulated fish population sizes typically varying over four orders of magnitude within a 50-year simulation run. The most sensitive parameters in the model relate to the amount of water (habitat) in the system: annual rainfall, seepage loss from the pools, and the carrying capacity (number of individuals per cubic meter) of the pools as they dry down. It seems likely that temporal source sink dynamics allow the fish populations to persist in these systems, with good years (high rainfall and brief cease-to-flow [CTF] periods) buffering against periods of drought. In dry years during which the stream may contract to very low numbers of pools, each of these persistent pools becomes crucial for the persistence of the population in the system. Climate change projections for this area suggest decreases in rainfall and increased incidence of drought; under these environmental conditions the long-term persistence of these fish populations is uncertain.
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Affiliation(s)
- George L W Perry
- School of Geography, Geology and Environmental Science, University of Auckland, Private Bag 92019, Auckland, New Zealand.
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9430
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Kim EH, Kim YS, Park SH, Koo YJ, Choi YD, Chung YY, Lee IJ, Kim JK. Methyl jasmonate reduces grain yield by mediating stress signals to alter spikelet development in rice. Plant Physiol 2009; 149:1751-60. [PMID: 19211695 PMCID: PMC2663756 DOI: 10.1104/pp.108.134684] [Citation(s) in RCA: 141] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2008] [Accepted: 02/04/2009] [Indexed: 05/18/2023]
Abstract
Jasmonic acid (JA) is involved in plant development and the defense response. Transgenic overexpression of the Arabidopsis (Arabidopsis thaliana) jasmonic acid carboxyl methyltransferase gene (AtJMT) linked to the Ubi1 promoter increased levels of methyl jasmonate (MeJA) by 6-fold in young panicles. Grain yield was greatly reduced in Ubi1:AtJMT plants due to a lower numbers of spikelets and lower filling rates than were observed for nontransgenic (NT) controls. Ubi1:AtJMT plants had altered numbers of spikelet organs, including the lemma/palea, lodicule, anther, and pistil. The loss of grain yield and alteration in spikelet organ numbers were reproduced by treating NT plants with exogenous MeJA, indicating that increased levels of MeJA in Ubi1:AtJMT panicles inhibited spikelet development. Interestingly, MeJA levels were increased by 19-fold in young NT panicles upon exposure to drought conditions, resulting in a loss of grain yield that was similar to that observed in Ubi1:AtJMT plants. Levels of abscisic acid (ABA) were increased by 1.9- and 1.4-fold in Ubi1:AtJMT and drought-treated NT panicles, respectively. The ABA increase in Ubi1:AtJMT panicles grown in nondrought conditions suggests that MeJA, rather than drought stress, induces ABA biosynthesis under drought conditions. Using microarray and quantitative polymerase chain reaction analyses, we identified seven genes that were regulated in both Ubi1:AtJMT and drought-treated NT panicles. Two genes, OsJMT1 and OsSDR (for short-chain alcohol dehydrogenase), are involved in MeJA and ABA biosynthesis, respectively, in rice (Oryza sativa). Overall, our results suggest that plants produce MeJA during drought stress, which in turn stimulates the production of ABA, together leading to a loss of grain yield.
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Affiliation(s)
- Eun Hye Kim
- School of Biotechnology and Environmental Engineering, Myongji University, Yongin 449-728, Korea
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9431
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Saha S, Holbrook NM, Montti L, Goldstein G, Cardinot GK. Water relations of Chusquea ramosissima and Merostachys claussenii in Iguazu National Park, Argentina. Plant Physiol 2009; 149:1992-9. [PMID: 19211704 PMCID: PMC2663761 DOI: 10.1104/pp.108.129015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2008] [Accepted: 02/04/2009] [Indexed: 05/02/2023]
Abstract
Bamboos are prominent components of many tropical ecosystems, yet little is known about the physiological mechanisms utilized by these gigantic forest grasses. Here, we present data on the water transport properties of Chusquea ramosissima and Merostachys claussenii, monocarpic bamboo grasses native to the subtropical Atlantic forests of Argentina. C. ramosissima and M. claussenii differed in their growth form and exhibited contrasting strategies of water transport. Maximum xylem hydraulic conductivity of C. ramosissima culms was 2-fold higher than that of M. claussenii. C. ramosissima cavitated at relatively high water potentials (50% loss of conductivity at >or=1 MPa), whereas M. claussenii was more drought tolerant (50% loss at
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Affiliation(s)
- Sonali Saha
- The Arnold Arboretum of Harvard University, Biological Laboratories, Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02130, USA.
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9432
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Klos RJ, Wang GG, Bauerle WL, Rieck JR. Drought impact on forest growth and mortality in the southeast USA: an analysis using Forest Health and Monitoring data. Ecol Appl 2009; 19:699-708. [PMID: 19425432 DOI: 10.1890/08-0330.1] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Drought frequency and intensity has been predicted to increase under many climate change scenarios. It is therefore critical to understand the response of forests to potential climate change in an effort to mitigate adverse impacts. The purpose of this study was to explore the regional effects of different drought severities on tree growth and mortality. Specifically, we investigated changes in growth and mortality rates across the southeastern United States under various drought and stand conditions using 1991-2005 Forest Health and Monitoring (FHM) plot data from Alabama, Georgia, and Virginia. Drought effects were examined for three species groups (pines, oaks, and mesophytic species) using the Palmer drought severity index (PDSI) as an indicator of drought severity. Stand variables, including total basal area, total tree density, tree species richness, slope, and stand age, were used to account for drought effects under varying stand conditions. The pines and mesophytic species exhibited significant reductions in growth rate with increasing drought severity. However, no significant difference in growth rate was observed within the oak species group. Mean mortality rates within the no-drought class were significantly lower than those within the other three drought classes, among which no significant differences were found, for both pines and mesophytic species. Mean mortality rates were not significantly different among drought classes for oaks. Total basal area, total tree density, and stand age were negatively related to growth and positively related to mortality, which suggests that older and denser stands are more susceptible to drought damage. The effect of basal area on growth increased with drought severity for the oak and mesophytic species groups. Tree species richness was negatively related to mortality for the pine and mesophytic species groups, indicating that stands with more species suffer less mortality. Slope was positively related to mortality within the mesophytic species group, and its effect increased with drought severity, indicating a higher mortality on sites of greater slope during severe-drought conditions. Our findings indicate that pines and mesophytic species are sensitive to drought, while oaks are tolerant of drought. The observed differential growth and mortality rates among species groups may alter the species composition of southeastern U.S. forests if drought episodes become more frequent and/or intense due to climate change. The significant effects of stand conditions on drought responses observed in our study also suggest that forest management may be used as a tool to mitigate drought effects.
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Affiliation(s)
- Ryan J Klos
- Department of Forestry and Natural Resources, Clemson University, Clemson, South Carolina 29634-0317, USA
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9433
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Cho EK, Choi YJ. A nuclear-localized HSP70 confers thermoprotective activity and drought-stress tolerance on plants. Biotechnol Lett 2009; 31:597-606. [PMID: 19034388 DOI: 10.1007/s10529-008-9880-5] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Revised: 11/05/2008] [Accepted: 11/10/2008] [Indexed: 12/23/2022]
Abstract
To investigate the function of nuclear-localized plant HSP70, we used NtHSP70-1 isolated from Nicotiana tabacum. The subcellular localization of NtHSP70-1 was identified by fluorescence microscopy for NtHSP70-1/GFP or smGFP fusion proteins in onion epidermal cells, obtained using particle gun bombardment. To analyze the drought-stress tolerance and thermoprotective role of NtHSP70-1, we obtained transgenic tobacco plants that constitutively expressed elevated levels of NtHSP70-1 as well as transgenic plants containing either the vector alone or else having NtHSP70-1 in the antisense orientation. From analysis for genomic DNA in transgenic seedlings after heat stress, NtHSP70-1 helps to prevent the fragmentation and degradation of nuclear DNA during heat stress. In addition, seedlings constitutively overexpressing NtHSP70-1 grew to be healthy plants, whereas transgenic vector or antisense seedlings resulted in death after heat-/drought-stress.
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Affiliation(s)
- Eun Kyung Cho
- Department of Bio-Food Materials, College of Medical Life Science, Silla University, Busan 617-736, South Korea.
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9434
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Chen CS, Xie ZX, Liu XJ. [Interactive effects of drought and salt stresses on winter wheat seedlings growth and physiological characteristics of stress-resistance]. Ying Yong Sheng Tai Xue Bao 2009; 20:811-816. [PMID: 19565760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In a hydroponic culture, different concentrations of PEG-6000 (0, 8.3%, and 12.6%, W/V) and NaCl (0, 25, and 50 mmol x L(-1) were added to simulate different degrees of drought and salt stresses, aimed to study their interactive effects on the winter wheat (cv. Cang-6001) seedlings growth and physiological characteristics of stress-resistance. The results showed that under the conditions of adding 8.3% and 12.6% of PEG-6000, the addition of 25 mmol NaCl x L(-1) increased the dry matter accumulation and water content in plant, the contents of soluble sugar and soluble protein in leaf and the Na+ content in shoot and root, while decreased the MDA and proline contents in leaf and the K+ content in shoot and root, compared with no NaCl addition. Adding 12.6% of PEG-6000 and 50 mmol x L(-1) of NaCl more inhibited plant growth, compared with no NaCl added. It was suggested that under drought stress, applying definite amount of salt could alleviate the deleterious effects of drought stress on winter wheat seedlings growth.
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Affiliation(s)
- Cheng-Sheng Chen
- Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang 050021, China.
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9435
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Parent B, Hachez C, Redondo E, Simonneau T, Chaumont F, Tardieu F. Drought and abscisic acid effects on aquaporin content translate into changes in hydraulic conductivity and leaf growth rate: a trans-scale approach. Plant Physiol 2009; 149:2000-12. [PMID: 19211703 PMCID: PMC2663730 DOI: 10.1104/pp.108.130682] [Citation(s) in RCA: 187] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2008] [Accepted: 02/06/2009] [Indexed: 05/18/2023]
Abstract
The effects of abscisic acid (ABA) on aquaporin content, root hydraulic conductivity (Lpr), whole plant hydraulic conductance, and leaf growth are controversial. We addressed these effects via a combination of experiments at different scales of plant organization and tested their consistency via a model. We analyzed under moderate water deficit a series of transformed maize (Zea mays) lines, one sense and three antisense, affected in NCED (for 9-cis-epoxycarotenoid dioxygenase) gene expression and that differed in the concentration of ABA in the xylem sap. In roots, the mRNA expression of most aquaporin PIP (for plasma membrane intrinsic protein) genes was increased in sense plants and decreased in antisense plants. The same pattern was observed for the protein contents of four PIPs. This resulted in more than 6-fold differences between lines in Lpr under both hydrostatic and osmotic gradients of water potential. This effect was probably due to differences in aquaporin activity, because it was nearly abolished by a hydrogen peroxide treatment, which blocks the water channel activity of aquaporins. The hydraulic conductance of intact whole plants was affected in the same way when measured either in steady-state conditions or via the rate of recovery of leaf water potential after rewatering. The recoveries of leaf water potential and elongation upon rehydration differed between lines and were accounted for by the experimentally measured Lpr in a model of water transfer. Overall, these results suggest that ABA has long-lasting effects on plant hydraulic properties via aquaporin activity, which contributes to the maintenance of a favorable plant water status.
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Affiliation(s)
- Boris Parent
- INRA, UMR 759 Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux, F-34060 Montpellier, France
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9436
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Abstract
To investigate the genetic factors underlying constitutive and adaptive root growth under different water-supply conditions, a double haploid (DH) population, derived from a cross between lowland rice variety IR64 and upland rice variety Azucena, with 284 molecular markers was used in cylindrical pot experiments. Several QTLs for seminal root length (SRL), adventitious root number (ARN) and total root dry weight (RW) respectively, under both flooding and upland conditions were detected. Two identical QTLs for SRL and RW were found under flooding and upland conditions. The relative parameters defined as the ratio of parameters under the two water-supply conditions were also used for QTL analysis. A comparative analysis among different genetic populations was performed for the QTLs for root traits and several consistent QTLs for root traits across genetic backgrounds were detected. Candidate genes for cell expansion and elongation were used for comparative mapping with the detected QTLs. Four cell wall-related expressed sequence tags (ESTs) for OsEXP2, OsEXP4, EXT and Xet were mapped on the intervals carrying the QTLs for root traits.
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Affiliation(s)
- Bing-Song Zheng
- The State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310029, China
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9437
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Abdel-Moneam MA. Heterosis in some crosses of bread wheat under irrigation and drought conditions. Pak J Biol Sci 2009; 12:486-491. [PMID: 19579996 DOI: 10.3923/pjbs.2009.486.491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Five bread wheat varieties with different characteristics were crossed in a half-diallel model in 2005/2006 season. The five parents and their 10 F1 hybrids were evaluated under normal and water stress conditions during 2006/2007 season, to estimate heterosis of some wheat crosses for drought tolerance and selecting the crosses which could be useful in breeding programs for drought tolerance. The results indicated that, the best crosses over their mid parents at water stress condition for days to heading was Sakha-61 x Sakha-93; for flag leaf area were Giza-168 x Gemmeiza-9 and Sakha-61 x Gemmeiza-9 and for plant height was Sakha-61 x Sakha-93. The best crosses over their mid parents at both normal and stress conditions for days to maturity was Sakha-61 x Gemmeiza-9; for flag leaf area were Giza-168 x Sakha-61, Sakha-8 x Gemmeiza-9 and Sakha-93 x Gemmeiza-9; for spikes/plant were Sakha-8 x Sakha-61, Sakha-8 x Gemmeiza-9 and Sakha-61 x Sakha-93; for kernels/spike were Giza-168 x Sakha-8, Giza-168 x Sakha-61, Giza-168 x Sakha-93 and Sakha-8 x Gemmeiza-9; for 100-kernel weight were Giza-168 x Gemmeiza-9, Sakha-61 x Sakha-93 and Sakha-93 x Gemmeiza-9 and for grain yield/plant were Giza-168 x Sakha-93, Sakha-8 x Gemmeiza-9 and Sakha-93 x Gemmeiza-9. The best crosses over their better parents at water stress condition for flag leaf area were Giza-168 x Sakha-8, Giza-168 x Gemmeiza-9 and Sakha-8 x Gemmeiza-9; for plant height were Giza-168 x Gemmeiza-9 and Sakha-8 x Sakha-61. The best crosses over better parents at both normal and stress conditions for plant height were Giza-168 x Sakha-8, Sakha-8 x Gemmeiza-9 and Sakha-93 x Gemmeiza-9; for spikes/plant were Sakha-8xSakha-61, Sakha-61 x Sakha-93 and Sakha-8 x Gemmeiza-9; forkernels/spike were Giza-168 x Sakha-61 and Giza-168 x Sakha-93 and for grain yield/plant were Sakha-61 x Sakha-93 and Sakha-93 x Gemmeiza-9. Estimation of useful heterosis over better parent for grain yield/plant proved that it never exceeds 10.16% at normal condition (cross Giza-168 x Gemmeiza-9) and 12.76% at stress condition (cross Sakha-93 x Gemmeiza-9). Useful segregate could be selected from such hybrids as hybrids wheat are still under experimentation in Egypt.
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Affiliation(s)
- M A Abdel-Moneam
- Department of Agronomy, Faculty of Agriculture, Mansoura University, Egypt
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9438
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Liu L, Hu X, Song J, Zong X, Li D, Li D. Over-expression of a Zea mays L. protein phosphatase 2C gene (ZmPP2C) in Arabidopsis thaliana decreases tolerance to salt and drought. J Plant Physiol 2009; 166:531-42. [PMID: 18930563 DOI: 10.1016/j.jplph.2008.07.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2008] [Revised: 07/19/2008] [Accepted: 07/21/2008] [Indexed: 05/20/2023]
Abstract
ZmPP2C (AY621066) is a protein phosphatase type-2c previously isolated from roots of Zea mays (LD9002). In this study, constitutive expression of ZmPP2C in Arabidopsis thaliana under the control of the Cauliflower Mosaic Virus (CaMV) 35S promoter decreased plant tolerance to salt and drought during seed germination and vegetative growth. When growing on media with NaCl or mannitol, the ZmPP2C-overexpressed plants displayed more severe damages, with weaker growth phenotypes corresponding to a series of physiological changes: lower net photosynthesis rate (Pn) and free proline content, higher malondialdehyde (MDA) level, higher relative membrane permeability (RMP), and water loss. Under these stress conditions, they also showed decreased transcription of the stress-related genes RD29A, RD29B, P5CS1, and P5CS2, and ABA-related genes ABI1 and ABI2. Further, the transgenic plants became less sensitive to abscisic acid (ABA). ZmPP2C over-expression significantly attenuated ABA inhibition on seed germination and root growth of the transgenic plants. These results demonstrate that ZmPP2C is involved in plant stress signal transduction, and ZmPP2C gene over-expression in Arabidopsis thaliana may be exploited to study its potential roles in stress-induced signaling pathway.
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Affiliation(s)
- Lixia Liu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, PR China
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9439
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9440
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Lee Y, Meneses CR, Fofana A, Lanzaro GC. Desiccation resistance among subpopulations of Anopheles gambiae s.s. from Selinkenyi, Mali. J Med Entomol 2009; 46:316-320. [PMID: 19351082 DOI: 10.1603/033.046.0216] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Certain forms of Anopheles gambiae s.s. actively maintain malaria transmission in the driest areas and months of the year because of considerable drought tolerance. We monitored desiccation resistance of F1 offspring of both the M and S forms of field-collected An. gambiae s.s. Our results indicate that the geographic cline in the distribution of the two forms, as observed in Mali, corresponds to a physiological difference in response to arid environments. In addition, female mosquitoes survived significantly longer than males, enhancing the vector competence for the malaria parasite. Our study supports a genetic link to the drought tolerance phenotype, a phenotype with important consequences to malaria transmission in many places in Africa.
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Affiliation(s)
- Yoosook Lee
- School of Veterinary Medicine, Department of Pathology, Microbiology and Immunology, University of California-Davis, Davis, CA 95616, USA.
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9441
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Song H, Zhao R, Fan P, Wang X, Chen X, Li Y. Overexpression of AtHsp90.2, AtHsp90.5 and AtHsp90.7 in Arabidopsis thaliana enhances plant sensitivity to salt and drought stresses. Planta 2009. [PMID: 19148673 DOI: 10.1007/s00425-008-0886.-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Three AtHsp90 isoforms, cytosolic AtHsp90.2, chloroplast-located AtHsp90.5, and endoplasmic reticulum (ER)-located AtHsp90.7, were characterized by constitutive overexpressing their genes in Arabidopsis thaliana. Both types of the transgenic plants overexpressing cytosolic and organellar AtHsp90s showed reduced tolerance to salt and drought stresses with lower germination rates and fresh weights, but improved tolerance to high concentration of Ca(2+) comparing with the wild type plants. Transcriptional analysis of ABA-responsive genes, RD29A, RD22 and KIN2 under salt and drought stresses, indicated that the induction expression of these genes was delayed by constitutive overexpression of cytosolic AtHsp90.2, but was hardly affected by that of organellar AtHsp90.5 and AtHsp90.7. These results implied that Arabidopsis different cellular compartments-located Hsp90s in Arabidopsis might be involved in abiotic stresses by different functional mechanisms, probably through ABA-dependent or Ca(2+) pathways, and proper homeostasis of Hsp90 was critical for cellular stress response and/or tolerance in plants.
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Affiliation(s)
- Hongmiao Song
- Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, 100093, Beijing, China
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9442
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Zhang J, Dell B, Conocono E, Waters I, Setter T, Appels R. Water deficits in wheat: fructan exohydrolase (1-FEH) mRNA expression and relationship to soluble carbohydrate concentrations in two varieties. New Phytol 2009; 181:843-850. [PMID: 19140945 DOI: 10.1111/j.1469-8137.2008.02713.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Terminal drought is a risk for wheat production in many parts of the world. Robust physiological traits for resilience would enhance the preselection of breeding lines in drought-prone areas. Three pot experiments were undertaken to characterize stem water-solublecarbohydrate (WSC), fructan exohydrolase expression, grain filling and leaf gas exchange in wheat (Triticum aestivum) varieties, Kauz and Westonia, which are considered to be drought-tolerant.Water deficit accelerated the remobilization of stem WSC in Westonia but not in Kauz. The profile of WSC accumulation and loss was negatively correlated with them RNA concentration of 1-FEH, especially 1-FEH w3 (1-FEH-6B). Under water deficit, Westonia showed lower concentrations of WSC than Kauz but did not show a corresponding drop in grain yield. The results from pot experiments suggest that stem WSC concentration is not, on its own, a reliable criterion to identify potential grain yield in wheat exposed to water deficits during grain filling. The expression of 1-FEH w3 may provide a better indicator when linked to osmotic potential and green leaf retention, and this requires validation in field-grown plants.
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Affiliation(s)
- Jingjuan Zhang
- Faculty of Sustainability, Environmental and Life Sciences, Murdoch University, South Street, WA, Australia, 6150
- Molecular Plant Breeding CRC, Murdoch University, South Street, WA, Australia, 6150
| | - Bernard Dell
- Faculty of Sustainability, Environmental and Life Sciences, Murdoch University, South Street, WA, Australia, 6150
| | - Elisabeth Conocono
- Department of Agriculture and Food Western Australia, 3 Baron Hay Court, South Perth, WA, Australia, 6151
| | - Irene Waters
- Department of Agriculture and Food Western Australia, 3 Baron Hay Court, South Perth, WA, Australia, 6151
| | - Tim Setter
- Department of Agriculture and Food Western Australia, 3 Baron Hay Court, South Perth, WA, Australia, 6151
| | - Rudi Appels
- Centre for Comparative Genomics, Murdoch University, South Street, WA, Australia, 6150
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9443
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Lv SL, Lian LJ, Tao PL, Li ZX, Zhang KW, Zhang JR. Overexpression of Thellungiella halophila H(+)-PPase (TsVP) in cotton enhances drought stress resistance of plants. Planta 2009; 229:899-910. [PMID: 19130078 DOI: 10.1007/s00425-008-0880-4] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2008] [Accepted: 12/18/2008] [Indexed: 05/23/2023]
Abstract
An H(+)-PPase gene, TsVP from Thellungiella halophila, was transferred into two cotton (Gossypium hirsutum) varieties (Lumianyan19 and Lumianyan 21) and southern and northern blotting analysis showed the foreign gene was integrated into the cotton genome and expressed. The measurement of isolated vacuolar membrane vesicles demonstrated that the transgenic plants had higher V-H(+)-PPase activity compared with wild-type plants (WT). Overexpressing TsVP in cotton improved shoot and root growth, and transgenic plants were much more resistant to osmotic/drought stress than the WT. Under drought stress conditions, transgenic plants had higher chlorophyll content, improved photosynthesis, higher relative water content of leaves and less cell membrane damage than WT. We ascribe these properties to improved root development and the lower solute potential resulting from higher solute content such as soluble sugars and free amino acids in the transgenic plants. In this study, the average seed cotton yields of transgenic plants from Lumianyan 19 and Lumianyan 21 were significantly increased compared with those of WT after exposing to drought stress for 21 days at flowering stage. The average seed cotton yields were 51 and 40% higher than in their WT counterparts, respectively. This study benefits efforts to improve cotton yields in arid and semiarid regions.
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MESH Headings
- Adaptation, Physiological/genetics
- Adaptation, Physiological/physiology
- Blotting, Northern
- Blotting, Southern
- Brassicaceae/enzymology
- Brassicaceae/genetics
- DNA, Plant/genetics
- Droughts
- Gene Expression Regulation, Developmental
- Gene Expression Regulation, Enzymologic
- Gene Expression Regulation, Plant
- Gossypium/genetics
- Gossypium/growth & development
- Gossypium/metabolism
- Inorganic Pyrophosphatase/genetics
- Inorganic Pyrophosphatase/metabolism
- Osmotic Pressure
- Photosynthesis/genetics
- Photosynthesis/physiology
- Plant Leaves/genetics
- Plant Leaves/growth & development
- Plant Leaves/metabolism
- Plant Proteins/genetics
- Plant Proteins/metabolism
- Plant Roots/genetics
- Plant Roots/growth & development
- Plant Roots/metabolism
- Plant Shoots/genetics
- Plant Shoots/growth & development
- Plant Shoots/metabolism
- Plants, Genetically Modified/genetics
- Plants, Genetically Modified/growth & development
- Plants, Genetically Modified/metabolism
- RNA, Plant/genetics
- RNA, Plant/metabolism
- Seedlings/genetics
- Seedlings/growth & development
- Seedlings/metabolism
- Time Factors
- Transgenes/genetics
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Affiliation(s)
- Su-Lian Lv
- School of Life Science, Shandong University, 27 Shanda South Road, Jinan, Shandong, 250100, China
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9444
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Kohzuma K, Cruz JA, Akashi K, Hoshiyasu S, Munekage YN, Yokota A, Kramer DM. The long-term responses of the photosynthetic proton circuit to drought. Plant Cell Environ 2009; 32:209-19. [PMID: 19021886 DOI: 10.1111/j.1365-3040.2008.01912.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Proton motive force (pmf) across thylakoid membranes is not only for harnessing solar energy for photosynthetic CO(2) fixation, but also for triggering feedback regulation of photosystem II antenna. The mechanisms for balancing these two roles of the proton circuit under the long-term environmental stress, such as prolonged drought, have been poorly understood. In this study, we report on the response of wild watermelon thylakoid 'proton circuit' to drought stress using both in vivo spectroscopy and molecular analyses of the representative photosynthetic components. Although drought stress led to enhanced proton flux via a approximately 34% increase in cyclic electron flow around photosystem I (PS I), an observed approximately fivefold decrease in proton conductivity, g(H)(+), across thylakoid membranes suggested that decreased ATP synthase activity was the major factor for sustaining elevated q(E). Western blotting analyses revealed that ATP synthase content decreased significantly, suggesting that quantitative control of the complex plays a pivotal role in down-regulation of g(H)(+). The expression level of cytochrome b(6)f complex - another key control point in photosynthesis - also declined, probably to prevent excess-reduction of PS I electron acceptors. We conclude that plant acclimation to long-term environmental stress involves global changes in the photosynthetic proton circuit, in which ATP synthase represents the key control point for regulating the relationship between electron transfer and pmf.
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Affiliation(s)
- Kaori Kohzuma
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, Japan
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9445
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Long SM, Reichenberg F, Lister LJ, Hankard PK, Townsend J, Mayer P, Wright J, Holmstrup M, Svendsen C, Spurgeon DJ. Combined chemical (fluoranthene) and drought effects on Lumbricus rubellus demonstrate the applicability of the independent action model for multiple stressor assessment. Environ Toxicol Chem 2009; 28:629-636. [PMID: 18980390 DOI: 10.1897/08-187.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2008] [Accepted: 09/28/2008] [Indexed: 05/27/2023]
Abstract
The combined effect of a chemical (fluoranthene) and a nonchemical stress (reduced soil moisture content) to the widely distributed earthworm Lumbricus rubellus were investigated in a laboratory study. Neither fluoranthene (up to 500 microg/g) nor low soil moisture (15% below optimal) had a significant effect on the survival of the exposed worms, but a significant effect on reproduction (cocoon production rate) was found for both stressors (p < 0.001 in both cases). The response of cocoon production to each stressor could be well described by a logistic model; this suggested that the joint effects may be applicable to description using the independent action (IA) model that is widely used in pharmacology and chemical mixture risk assessment. Fitting of the IA model provided a good description of the combined stressor data (accounting for 53.7% of total variation) and was the most parsimonious model describing joint effect (i.e., the description of the data was not improved by addition of further parameters accounting for synergism or antagonism). Thus, the independent action of the two responses was further supported by measurement of internal fluoranthene exposure. The chemical activity of fluoranthene in worm tissue was correlated only with soil fluoranthene concentration and not with soil moisture content. Taken together these results suggest that the IA model can help interpret the joint effects of chemical and nonchemical stressors. Such analyses should, however, be done with caution since the literature data set suggests that there may be cases where interactions between stressors result in joint effects that differ significantly from IA predictions.
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Affiliation(s)
- Sara M Long
- Centre for Ecology and Hydrology, Monks Wood, Abbots Ripton Huntingdon, Cambridgeshire, United Kingdom
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9446
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Carmo-Silva AE, Keys AJ, Beale MH, Ward JL, Baker JM, Hawkins ND, Arrabaça MC, Parry MAJ. Drought stress increases the production of 5-hydroxynorvaline in two C4 grasses. Phytochemistry 2009; 70:664-71. [PMID: 19359022 DOI: 10.1016/j.phytochem.2009.03.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2008] [Revised: 02/16/2009] [Accepted: 03/02/2009] [Indexed: 05/20/2023]
Abstract
Plants produce various compounds in response to water deficit. Here, the presence and identification of a drought-inducible non-protein amino acid in the leaves of two C(4) grasses is first reported. The soluble amino acids extracted from the leaves of three different species were measured by high-performance liquid chromatography of derivatives formed with o-phthaldialdehyde and beta-mercaptoethanol. One amino acid that increased in amount with drought stress had a retention time not corresponding to any common amino acid. Its identity was determined by metabolite profiling, using (1)H NMR and GC-MS. This unusual amino acid was present in the dehydrated leaves of Cynodon dactylon (L.) Pers. and Zoysia japonica Steudel, but was absent from Paspalum dilatatum Poir. Its identity as 2-amino-5-hydroxypentanoic acid (5-hydroxynorvaline, 5-HNV) was confirmed by synthesis and co-chromatography of synthetic and naturally occurring compounds. The amount of 5-HNV in leaves of the more drought tolerant C(4) grasses, C. dactylon and Z. japonica, increased with increasing water deficit; therefore, any benefits from this unusual non-protein amino acid for drought resistance should be further explored.
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Affiliation(s)
- Ana E Carmo-Silva
- Centro de Engenharia Biológica and Departamento de Biologia Vegetal, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal.
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9447
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Song H, Zhao R, Fan P, Wang X, Chen X, Li Y. Overexpression of AtHsp90.2, AtHsp90.5 and AtHsp90.7 in Arabidopsis thaliana enhances plant sensitivity to salt and drought stresses. Planta 2009; 229:955-64. [PMID: 19148673 DOI: 10.1007/s00425-008-0886-y] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2008] [Accepted: 12/23/2008] [Indexed: 05/24/2023]
Abstract
Three AtHsp90 isoforms, cytosolic AtHsp90.2, chloroplast-located AtHsp90.5, and endoplasmic reticulum (ER)-located AtHsp90.7, were characterized by constitutive overexpressing their genes in Arabidopsis thaliana. Both types of the transgenic plants overexpressing cytosolic and organellar AtHsp90s showed reduced tolerance to salt and drought stresses with lower germination rates and fresh weights, but improved tolerance to high concentration of Ca(2+) comparing with the wild type plants. Transcriptional analysis of ABA-responsive genes, RD29A, RD22 and KIN2 under salt and drought stresses, indicated that the induction expression of these genes was delayed by constitutive overexpression of cytosolic AtHsp90.2, but was hardly affected by that of organellar AtHsp90.5 and AtHsp90.7. These results implied that Arabidopsis different cellular compartments-located Hsp90s in Arabidopsis might be involved in abiotic stresses by different functional mechanisms, probably through ABA-dependent or Ca(2+) pathways, and proper homeostasis of Hsp90 was critical for cellular stress response and/or tolerance in plants.
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Affiliation(s)
- Hongmiao Song
- Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, 100093, Beijing, China
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9448
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Hura T, Hura K, Grzesiak S. Physiological and biochemical parameters for identification of QTLs controlling the winter triticale drought tolerance at the seedling stage. Plant Physiol Biochem 2009; 47:210-4. [PMID: 19059788 DOI: 10.1016/j.plaphy.2008.11.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2008] [Accepted: 11/09/2008] [Indexed: 05/01/2023]
Abstract
The genetic map of the triticale is created on the basis of double-haploid (DH) lines, derived from F1 hybrids of a cross between the parental line Saka3006 and Modus. In order to localise drought resistance genes, it is necessary to find a phenotype feature which clearly differentiates between parental lines under drought stress conditions. With the future in mind, the aim of the presented studies was to analyse differences in the response to drought stress, between Saka3006 and Modus. Analyses of the water status of leaves, and the activity of the photosynthetic apparatus and protective mechanisms relating to the accumulation of phenolic compounds, were carried out. The studies were completed during the tillering phase. Statistically significant changes, between genotypes experiencing the drought period, were noticed for the osmotic potential, leaf water content, some parameters of chlorophyll fluorescence, and for phenolics and the ferulic acid content. On the basis of the studies, the Saka genotype can be considered drought resistant due to higher leaf water content caused, probably, by smaller hydraulic resistance relative to Modus. The activity of its photosynthetic apparatus during drought was higher than that for the Modus genotype. The high level of phenolic compounds, which can act as photoprotectors and free radical scavengers, was also maintained. All the mentioned parameters can represent the potential phenotype features, which allow the identification of resistance genes on the genetic map of the triticale, which is currently being created.
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Affiliation(s)
- Tomasz Hura
- The Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Niezapominajek 21, 30-239 Kraków, Poland.
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9449
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Urano K, Maruyama K, Ogata Y, Morishita Y, Takeda M, Sakurai N, Suzuki H, Saito K, Shibata D, Kobayashi M, Yamaguchi-Shinozaki K, Shinozaki K. Characterization of the ABA-regulated global responses to dehydration in Arabidopsis by metabolomics. Plant J 2009; 57:1065-78. [PMID: 19036030 DOI: 10.1111/j.1365-313x.2008.03748.x] [Citation(s) in RCA: 311] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Drought is the major environmental threat to agricultural production and distribution worldwide. Adaptation by plants to dehydration stress is a complex biological process that involves global changes in gene expression and metabolite composition. Here, using one type of functional genomics analysis, metabolomics, we characterized the metabolic phenotypes of Arabidopsis wild-type and a knockout mutant of the NCED3 gene (nc3-2) under dehydration stress. NCED3 plays a role in the dehydration-inducible biosynthesis of abscisic acid (ABA), a phytohormone that is important in the dehydration-stress response in higher plants. Metabolite profiling performed using two types of mass spectrometry (MS) systems, gas chromatography/time-of-flight MS (GC/TOF-MS) and capillary electrophoresis MS (CE-MS), revealed that accumulation of amino acids depended on ABA production, but the level of the oligosaccharide raffinose was regulated by ABA independently under dehydration stress. Metabolic network analysis showed that global metabolite-metabolite correlations occurred in dehydration-increased amino acids in wild-type, and strong correlations with raffinose were reconstructed in nc3-2. An integrated metabolome and transcriptome analysis revealed ABA-dependent transcriptional regulation of the biosynthesis of the branched-chain amino acids, saccharopine, proline and polyamine. This metabolomics analysis revealed new molecular mechanisms of dynamic metabolic networks in response to dehydration stress.
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Affiliation(s)
- Kaoru Urano
- Gene Discovery Research Group, RIKEN Plant Science Center, 3-1-1 Koyadai, Tsukuba, Ibaraki, Japan
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9450
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Abstract
We implemented Ayers and Vachers' (1986) inclusive conceptual model for atoll island aquifers in a comprehensive numerical modeling study to evaluate the response of the fresh water lens to selected controlling climatic and geologic variables. Climatic factors include both constant and time-varying recharge rates, with particular attention paid to the effects of El Niño and the associated drought it brings to the western Pacific. Geologic factors include island width; hydraulic conductivity of the uppermost Holocene-age aquifer, which contains the fresh water lens; the depth to the contact with the underlying, and much more conductive, Pleistocene karst aquifer, which transmits tidal signals to the base of the lens; and the presence or absence of a semiconfining reef flat plate on the ocean side. Sensitivity analyses of steady-steady simulations show that lens thickness is most strongly sensitive to the depth to the Holocene-Pleistocene contact and to the hydraulic conductivity of the Holocene aquifer, respectively. Comparisons between modeling results and published observations of atoll island lens thicknesses suggest a hydraulic conductivity of approximately 50 m/d for leeward islands and approximately 400 m/d for windward islands. Results of transient simulations show that lens thickness fluctuations during average seasonal conditions and El Niño events are quite sensitive to island width, recharge rate, and hydraulic conductivity of the Holocene aquifer. In general, the depletion of the lens during drought conditions is most drastic for small, windward islands. Simulation results suggest that recovery from a 6-month drought requires about 1.5 years.
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Affiliation(s)
- R T Bailey
- Department of Civil and Environmental Engineering, Colorado State University, Fort Collins, CO 80523, USA.
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