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Ricardo Aroca - One of the best experts on this subject based on the ideXlab platform.
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Techniques to Determine the Effects of Jasmonates on Root Hydraulic Conductivity.
Methods in molecular biology (Clifton N.J.), 2019Co-Authors: Beatriz Sánchez-Romera, Ricardo ArocaAbstract:Plants subjected to drought and saline stress conditions suffer from tissue dehydration. Such dehydration is caused by the imbalance between Root water uptake by Roots and water loss by transpiration. Therefore, determination of Root Hydraulic properties is crucial to understand plant water balance. Root Hydraulic Conductivity (L) can be used to estimate Root water transport capacity. L depends on Root architecture (length and diameter of the Root and proliferation of secondary Roots), radial water transport pathway (Root xylem vessels, plasmodesmata, apoplastic space, caspary bands), and on intrinsic membrane permeability to water (aquaporins, water membrane protein channels). Different methods have been developed to measure L, such as Pressure Chamber, Free Exudation, High-Pressure Flowmeter (HPFM), and Root Pressure Probe (RPP). In this chapter, we will focus on Pressure Chamber, Free Exudation, and HPFM methods which have been used to determine the effect of jasmonates (JA) on Root Hydraulic Conductivity.
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Contribution of the arbuscular mycorrhizal symbiosis to the regulation of radial Root water transport in maize plants under water deficit
Environmental and Experimental Botany, 2019Co-Authors: Gabriela Quiroga, Ricardo Aroca, Gorka Erice, François Chaumont, Juan Manuel Ruiz-lozanoAbstract:Abstract In Roots, water flows radially through three parallel pathways: apoplastic, symplastic and transcellular (the last two referred as the cell-to-cell), with a different contribution depending on the environmental conditions. Thus, during drought, the cell-to-cell pathway, which is largely regulated by aquaporins, dominates. While it is accepted that water can flow across Roots following the apoplastic, symplastic and transcellular pathways, the relative contribution of these pathways to whole Root Hydraulic Conductivity is not well stablished. In addition, the symbiosis with arbuscular mycorrhizal (AM) fungi was reported to modify Root water transport in host plants. This study aims to understand if the AM symbiosis alters radial Root water transport in the host plant and whether this modification is due to alteration of plant aquaporins activity or amounts and/or changes in apoplastic barriers. Hence, the combined effect of mycorrhizal fungus, water deficit and application of the aquaporin inhibitor sodium azide (NaN3) on radial Root water transport of maize plants was analyzed. The development of Casparian bands in these Roots was also assessed. NaN3 clearly inhibited osmotic Root Hydraulic Conductivity (Lo). However, the inhibitory effect of sodium azide on Lo was lower in AM plants than in non-AM plants, which together with their higher relative apoplastic water flow values suggests a compensatory mechanism for aquaporin activity inhibition in AM plants, leading to a higher hydrostatic Root Hydraulic Conductivity (Lpr) compared to non-AM plants. This effect seems to be related to the mycorrhizal regulation of aquaporins activity through posttranslational modifications. The development of Casparian bands increased with drought and AM colonization, although this did not decrease water flow values in AM plants. The work provides new clues on the differential mycorrhizal regulation of Root water transport.
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Arbuscular mycorrhizal symbiosis and methyl jasmonate avoid the inhibition of Root Hydraulic Conductivity caused by drought
Mycorrhiza, 2016Co-Authors: Beatriz Sánchez-Romera, Angel M. Zamarreño, José-maria Garcia-mina, Juan Manuel Ruiz-lozano, Ricardo ArocaAbstract:Hormonal regulation and symbiotic relationships provide benefits for plants to overcome stress conditions. The aim of this study was to elucidate the effects of exogenous methyl jasmonate (MeJA) application on Root Hydraulic Conductivity (L) of Phaseolus vulgaris plants which established arbuscular mycorrhizal (AM) symbiosis under two water regimes (well-watered and drought conditions). The variation in endogenous contents of several hormones (MeJA, JA, abscisic acid (ABA), indol-3-acetic acid (IAA), salicylic acid (SA)) and the changes in aquaporin gene expression, protein abundance and phosphorylation state were analyzed. AM symbiosis decreased L under well-watered conditions, which was partially reverted by the MeJA treatment, apparently by a drop in Root IAA contents. Also, AM symbiosis and MeJA prevented inhibition of L under drought conditions, most probably by a reduction in Root SA contents. Additionally, the gene expression of two fungal aquaporins was upregulated under drought conditions, independently of the MeJA treatment. Plant aquaporin gene expression could not explain the behaviour of L. Conversely, evidence was found for the control of L by phosphorylation of aquaporins. Hence, MeJA addition modified the response of L to both AM symbiosis and drought, presumably by regulating the Root contents of IAA and SA and the phosphorylation state of aquaporins.
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Exploring the use of recombinant inbred lines in combination with beneficial microbial inoculants (AM fungus and PGPR) to improve drought stress tolerance in tomato
Environmental and Experimental Botany, 2016Co-Authors: Mónica Calvo-polanco, Beatriz Sánchez-Romera, Ricardo Aroca, Ian C. Dodd, Stephane Declerck, Cristina Martinez-andujar, Alfonso Albacete, M. J. Asins, Juan Manuel Ruiz-lozanoAbstract:At a world scale, tomato is an important horticultural crop, but its productivity is highly reduced by drought stress. Combining the application of beneficial microbial inoculants with breeding and grafting techniques may be key to cope with reduced tomato yield under drought. This study aimed to investigate the growth responses and physiological mechanisms involved in the performance under drought stress of four tomato recombinant inbred lines (RIL) after inoculation with the arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis and the plant growth promoting rhizobacteria (PGPR) Variovorax paradoxus 5C-2. Results showed a variation in the efficiency of the different tomato RILs under drought stress and a differential effect of the microbial inoculants, depending on the RIL involved. The inoculants affected plant parameters such as net photosynthetic capacity, oxidative damage to lipids, osmolyte accumulation, Root Hydraulic Conductivity or aquaporin abundance and phosphorylation status. RIL66 was the one obtaining maximum benefit from the microbial inoculants under drought stress conditions, due likely to improved CO2-fixation capacity and Root Hydraulic Conductivity. We propose that RIL66 could be selected as a good plant material to be used as Rootstock to improve tomato growth and productivity under water limiting conditions. Since RIL66 is highly responsive to microbial inoculants, this grafting strategy should be combined with inoculation of R. irregularis and V. paradoxus in order to improve plant yield under conditions of drought stress.[EN]This research has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 289365 (RootOPOWER project).Peer reviewe
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Enhancement of Root Hydraulic Conductivity by methyl jasmonate and the role of calcium and abscisic acid in this process.
Plant Cell and Environment, 2014Co-Authors: Beatriz Sánchez-Romera, Angel M. Zamarreño, José-maria Garcia-mina, Juan Manuel Ruiz-lozano, Micaela Carvajal, Doan-trung Luu, Maria Del Carmen Martínez-ballesta, Christophe Maurel, Ricardo ArocaAbstract:The role of jasmonic acid in the induction of stomatal closure is well known. However, its role in regulating Root Hydraulic Conductivity (L) has not yet been explored. The objectives of the present research were to evaluate how JA regulates L and how calcium and abscisic acid (ABA) could be involved in such regulation. We found that exogenous methyl jasmonate (MeJA) increased L of Phaseolus vulgaris, Solanum lycopersicum and Arabidopsis thaliana Roots. Tomato plants defective in JA biosynthesis had lower values of L than wild-type plants, and that L was restored by addition of MeJA. The increase of L by MeJA was accompanied by an increase of the phosphorylation state of the aquaporin PIP2. We observed that MeJA addition increased the concentration of cytosolic calcium and that calcium channel blockers inhibited the rise of L caused by MeJA. Treatment with fluoridone, an inhibitor of ABA biosynthesis, partially inhibited the increase of L caused by MeJA, and tomato plants defective in ABA biosynthesis increased their L after application of MeJA. It is concluded that JA enhances L and that this enhancement is linked to calcium and ABA dependent and independent signalling pathways.
Janusz J. Zwiazek - One of the best experts on this subject based on the ideXlab platform.
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Effects of Root medium pH on Root water transport and apoplastic pH in red-osier dogwood (Cornus sericea) and paper birch (Betula papyrifera) seedlings.
Plant biology (Stuttgart Germany), 2016Co-Authors: W. Zhang, Janusz J. ZwiazekAbstract:Soil pH is a major factor affecting plant growth. Plant responses to pH conditions widely vary between different species of plants. However, the exact mechanisms of high pH tolerance of plants are largely unknown. In the present study, we compared the pH responses of paper birch (Betula papyrifera) seedlings, a relatively sensitive species to high soil pH, with red-osier dogwood (Cornus sericea), reported to be relatively tolerant of high pH conditions. We examined the hypotheses that tolerance of plants to high Root zone pH is linked to effective control of Root apoplastic pH to facilitate nutrient and water transport processes In the study, we exposed paper birch and red-osier dogwood seedlings for six weeks to pH 5, 7 and 9 under controlled-environment conditions in hydroponic culture. Then, we measured biomass, gas exchange, Root Hydraulic Conductivity, ferric chelate reductase (FCR) activity, xylem sap pH and the relative abundance of major elements in leaf protoplasts and apoplasts. The study sheds new light on the rarely studied high pH tolerance mechanisms in plants. We found that compared with paper birch, red-osier dogwood showed greater growth, higher gas exchange, and maintained higher Root Hydraulic Conductivity as well as lower xylem sap pH under high pH conditions. The results suggest that the relatively high pH tolerance of dogwood is associated with greater water uptake ability and maintenance of low apoplastic pH. These traits may have a significant impact on the uptake of Fe and Mn by leaf cells.
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Overexpression of Laccaria bicolor aquaporin JQ585595 alters Root water transport properties in ectomycorrhizal white spruce (Picea glauca) seedlings.
The New phytologist, 2014Co-Authors: Minna Kemppainen, Walid El Kayal, Seong Hee Lee, Alejandro G. Pardo, Janice E. K. Cooke, Janusz J. ZwiazekAbstract:The contribution of hyphae to water transport in ectomycorrhizal (ECM) white spruce (Picea glauca) seedlings was examined by altering expression of a major water-transporting aquaporin in Laccaria bicolor. Picea glauca was inoculated with wild-type (WT), mock transgenic or L. bicolor aquaporin JQ585595-overexpressing (OE) strains and exposed to Root temperatures ranging from 5 to 20°C to examine the Root water transport properties, physiological responses and plasma membrane intrinsic protein (PIP) expression in colonized plants. Mycorrhization increased shoot water potential, transpiration, net photosynthetic rates, Root Hydraulic Conductivity and Root cortical cell Hydraulic Conductivity in seedlings. At 20°C, OE plants had higher Root Hydraulic Conductivity compared with WT plants and the increases were accompanied by higher expression of P. glauca PIP GQ03401_M18.1 in Roots. In contrast to WT L. bicolor, the effects of OE fungi on Root and Root cortical cell Hydraulic conductivities were abolished at 10 and 5°C in the absence of major changes in the examined transcript levels of P. glauca Root PIPs. The results provide evidence for the importance of fungal aquaporins in Root water transport of mycorrhizal plants. They also demonstrate links between hyphal water transport, Root aquaporin expression and Root water transport in ECM plants.
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Ectomycorrhizas and water relations of trees: a review
Mycorrhiza, 2011Co-Authors: Tarja Lehto, Janusz J. ZwiazekAbstract:There is plenty of evidence for improved nutrient acquisition by ectomycorrhizas in trees; however, their role in water uptake is much less clear. In addition to experiments showing improved performance during drought by mycorrhizal plants, there are several studies showing reduced Root Hydraulic Conductivity and reduced water uptake in mycorrhizal Roots. The clearest direct mechanism for increased water uptake is the increased extension growth and absorbing surface area, particularly in fungal species with external mycelium of the long-distance exploration type. Some studies have found increased aquaporin function and, consequently, increased Root Hydraulic Conductivity in ectomycorrhizal plants while other studies showed no effect of ectomycorrhizal associations on Root water flow properties. The aquaporin function of the fungal hyphae is also likely to be important for the uptake of water by the ectomycorrhizal plant, but more work needs to be done in this area. The best-known indirect mechanism for mycorrhizal effects on water relations is improved nutrient status of the host. Others include altered carbohydrate assimilation via stomatal function, possibly mediated by changes in growth regulator balance; increased sink strength in mycorrhizal Roots; antioxidant metabolism; and changes in osmotic adjustment. None of these possibilities has been sufficiently explored. The mycorrhizal structure may also reduce water movement because of different fine Root architecture (thickness), cell wall hydrophobicity or the larger number of membranes that water has to cross on the way from the soil to the xylem. In future studies, pot experiments comparing mycorrhizal and nonmycorrhizal plants will still be useful in studying well-defined physiological details. However, the quantitative importance of ectomycorrhizas for tree water uptake and water relations can only be assessed by field studies using innovative approaches. Hydraulic redistribution can support nutrient uptake during prolonged dry periods. In large trees with deep Root systems, it may turn out that the most important function of mycorrhizas during drought is to facilitate nutrient acquisition.
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cycloheximide inhibits Root water flow and stomatal conductance in aspen populus tremuloides seedlings
Plant Cell and Environment, 2004Co-Authors: Mihaela C Voicu, Janusz J. ZwiazekAbstract:Aspen (Populus tremuloides Michx.) Roots were treated with cycloheximide, a protein synthesis inhibitor, to examine the role of protein synthesis in Root water transport and plant water relations. Within less than 30 min following Root application, cycloheximide inhibited steady-state Root water flow rates and 1 h after the application of 1 mM cycloheximide, Root Hydraulic Conductivity had decreased by 85% compared with control Roots. However, stomatal conductance showed a significant inhibition only after 2 h following cycloheximide treatment. The reduction in Root Hydraulic Conductivity was accompanied by an almost three-fold increase in the apoplastic water flow ratio as determined by the trisodium 3-hydroxy-5,8,10-pyrene-sulphonate tracer dye. Cycloheximide-treated Roots showed a decrease in the immunostaining intensity of a 32 kDa microsomal protein band that immunoreacted with the AnthPIP1; 1 antibody suggesting a decrease in the membrane aquaporin expression. These changes occurred without severe metabolic disruptions as measured by Root respiration. The results point to the importance of protein-mediated transport in Roots and the rapidity of response suggests that protein synthesis may be used as a principal regulatory mechanism in Root water transport in aspen.
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Fluoride inhibits Root water transport and affects leaf expansion and gas exchange in aspen (Populus tremuloides) seedlings.
Physiologia plantarum, 2003Co-Authors: M. Kamaluddin, Janusz J. ZwiazekAbstract:The effects of sodium fluoride (0.3, 5 and 10 mM NaF) on Root Hydraulic Conductivity, and gas exchange processes were examined in aspen (Populus tremuloides Michx.) seedlings grown in solution culture. A long-term exposure of Roots to NaF significantly decreased Root Hydraulic Conductivity (Lp) and stomatal conductance (g s ). Root absorbed NaF significantly affected electrolyte leakage in leaf tissues and substantially restricted leaf expansion. NaF did not significantly affect leaf chlorophyll contents but decreased net photosynthesis (P n ). A short-term exposure of excised Roots to 5 mM NaF and KF significantly decreased Root water flow (Q v ) with a concomitant decline in Root respiration and reduced g s when applied through intact Roots or excised stems. The same molar concentration of NaCl also decreased Q v and g s in intact seedlings, but to a lesser extent than NaF or KF, and did not significantly affect Root respiration. The results suggest that fluoride metabolically inhibited Q v or Lp, probably by affecting water channel activity. We suggest that the metabolic inhibition of Lp by Root-absorbed fluoride affected gas exchange and leaf expansion in aspen seedlings.
Juan Manuel Ruiz-lozano - One of the best experts on this subject based on the ideXlab platform.
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Contribution of the arbuscular mycorrhizal symbiosis to the regulation of radial Root water transport in maize plants under water deficit
Environmental and Experimental Botany, 2019Co-Authors: Gabriela Quiroga, Ricardo Aroca, Gorka Erice, François Chaumont, Juan Manuel Ruiz-lozanoAbstract:Abstract In Roots, water flows radially through three parallel pathways: apoplastic, symplastic and transcellular (the last two referred as the cell-to-cell), with a different contribution depending on the environmental conditions. Thus, during drought, the cell-to-cell pathway, which is largely regulated by aquaporins, dominates. While it is accepted that water can flow across Roots following the apoplastic, symplastic and transcellular pathways, the relative contribution of these pathways to whole Root Hydraulic Conductivity is not well stablished. In addition, the symbiosis with arbuscular mycorrhizal (AM) fungi was reported to modify Root water transport in host plants. This study aims to understand if the AM symbiosis alters radial Root water transport in the host plant and whether this modification is due to alteration of plant aquaporins activity or amounts and/or changes in apoplastic barriers. Hence, the combined effect of mycorrhizal fungus, water deficit and application of the aquaporin inhibitor sodium azide (NaN3) on radial Root water transport of maize plants was analyzed. The development of Casparian bands in these Roots was also assessed. NaN3 clearly inhibited osmotic Root Hydraulic Conductivity (Lo). However, the inhibitory effect of sodium azide on Lo was lower in AM plants than in non-AM plants, which together with their higher relative apoplastic water flow values suggests a compensatory mechanism for aquaporin activity inhibition in AM plants, leading to a higher hydrostatic Root Hydraulic Conductivity (Lpr) compared to non-AM plants. This effect seems to be related to the mycorrhizal regulation of aquaporins activity through posttranslational modifications. The development of Casparian bands increased with drought and AM colonization, although this did not decrease water flow values in AM plants. The work provides new clues on the differential mycorrhizal regulation of Root water transport.
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Arbuscular mycorrhizal symbiosis and methyl jasmonate avoid the inhibition of Root Hydraulic Conductivity caused by drought
Mycorrhiza, 2016Co-Authors: Beatriz Sánchez-Romera, Angel M. Zamarreño, José-maria Garcia-mina, Juan Manuel Ruiz-lozano, Ricardo ArocaAbstract:Hormonal regulation and symbiotic relationships provide benefits for plants to overcome stress conditions. The aim of this study was to elucidate the effects of exogenous methyl jasmonate (MeJA) application on Root Hydraulic Conductivity (L) of Phaseolus vulgaris plants which established arbuscular mycorrhizal (AM) symbiosis under two water regimes (well-watered and drought conditions). The variation in endogenous contents of several hormones (MeJA, JA, abscisic acid (ABA), indol-3-acetic acid (IAA), salicylic acid (SA)) and the changes in aquaporin gene expression, protein abundance and phosphorylation state were analyzed. AM symbiosis decreased L under well-watered conditions, which was partially reverted by the MeJA treatment, apparently by a drop in Root IAA contents. Also, AM symbiosis and MeJA prevented inhibition of L under drought conditions, most probably by a reduction in Root SA contents. Additionally, the gene expression of two fungal aquaporins was upregulated under drought conditions, independently of the MeJA treatment. Plant aquaporin gene expression could not explain the behaviour of L. Conversely, evidence was found for the control of L by phosphorylation of aquaporins. Hence, MeJA addition modified the response of L to both AM symbiosis and drought, presumably by regulating the Root contents of IAA and SA and the phosphorylation state of aquaporins.
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Exploring the use of recombinant inbred lines in combination with beneficial microbial inoculants (AM fungus and PGPR) to improve drought stress tolerance in tomato
Environmental and Experimental Botany, 2016Co-Authors: Mónica Calvo-polanco, Beatriz Sánchez-Romera, Ricardo Aroca, Ian C. Dodd, Stephane Declerck, Cristina Martinez-andujar, Alfonso Albacete, M. J. Asins, Juan Manuel Ruiz-lozanoAbstract:At a world scale, tomato is an important horticultural crop, but its productivity is highly reduced by drought stress. Combining the application of beneficial microbial inoculants with breeding and grafting techniques may be key to cope with reduced tomato yield under drought. This study aimed to investigate the growth responses and physiological mechanisms involved in the performance under drought stress of four tomato recombinant inbred lines (RIL) after inoculation with the arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis and the plant growth promoting rhizobacteria (PGPR) Variovorax paradoxus 5C-2. Results showed a variation in the efficiency of the different tomato RILs under drought stress and a differential effect of the microbial inoculants, depending on the RIL involved. The inoculants affected plant parameters such as net photosynthetic capacity, oxidative damage to lipids, osmolyte accumulation, Root Hydraulic Conductivity or aquaporin abundance and phosphorylation status. RIL66 was the one obtaining maximum benefit from the microbial inoculants under drought stress conditions, due likely to improved CO2-fixation capacity and Root Hydraulic Conductivity. We propose that RIL66 could be selected as a good plant material to be used as Rootstock to improve tomato growth and productivity under water limiting conditions. Since RIL66 is highly responsive to microbial inoculants, this grafting strategy should be combined with inoculation of R. irregularis and V. paradoxus in order to improve plant yield under conditions of drought stress.[EN]This research has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 289365 (RootOPOWER project).Peer reviewe
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Enhancement of Root Hydraulic Conductivity by methyl jasmonate and the role of calcium and abscisic acid in this process.
Plant Cell and Environment, 2014Co-Authors: Beatriz Sánchez-Romera, Angel M. Zamarreño, José-maria Garcia-mina, Juan Manuel Ruiz-lozano, Micaela Carvajal, Doan-trung Luu, Maria Del Carmen Martínez-ballesta, Christophe Maurel, Ricardo ArocaAbstract:The role of jasmonic acid in the induction of stomatal closure is well known. However, its role in regulating Root Hydraulic Conductivity (L) has not yet been explored. The objectives of the present research were to evaluate how JA regulates L and how calcium and abscisic acid (ABA) could be involved in such regulation. We found that exogenous methyl jasmonate (MeJA) increased L of Phaseolus vulgaris, Solanum lycopersicum and Arabidopsis thaliana Roots. Tomato plants defective in JA biosynthesis had lower values of L than wild-type plants, and that L was restored by addition of MeJA. The increase of L by MeJA was accompanied by an increase of the phosphorylation state of the aquaporin PIP2. We observed that MeJA addition increased the concentration of cytosolic calcium and that calcium channel blockers inhibited the rise of L caused by MeJA. Treatment with fluoridone, an inhibitor of ABA biosynthesis, partially inhibited the increase of L caused by MeJA, and tomato plants defective in ABA biosynthesis increased their L after application of MeJA. It is concluded that JA enhances L and that this enhancement is linked to calcium and ABA dependent and independent signalling pathways.
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Plant potassium content modifies the effects of arbuscular mycorrhizal symbiosis on Root Hydraulic properties in maize plants.
Mycorrhiza, 2012Co-Authors: Mohamed Najib El-mesbahi, Juan Manuel Ruiz-lozano, Rosario Azcón, Ricardo ArocaAbstract:It is well known that the arbuscular mycorrhizal (AM) symbiosis helps the host plant to overcome several abiotic stresses including drought. One of the mechanisms for this drought tolerance enhancement is the higher water uptake capacity of the mycorrhizal plants. However, the effects of the AM symbiosis on processes regulating Root Hydraulic properties of the host plant, such as Root Hydraulic Conductivity and plasma membrane aquaporin gene expression, and protein abundance, are not well defined. Since it is known that K(+) status is modified by AM and that it regulates Root Hydraulic properties, it has been tested how plant K(+) status could modify the effects of the symbiosis on Root Hydraulic Conductivity and plasma membrane aquaporin gene expression and protein abundance, using maize (Zea mays L.) plants and Glomus intraradices as a model. It was observed that the supply of extra K(+) increased Root Hydraulic Conductivity only in AM plants. Also, the different pattern of plasma membrane aquaporin gene expression and protein abundance between AM and non-AM plants changed with the application of extra K(+). Thus, plant K(+) status could be one of the causes of the different observed effects of the AM symbiosis on Root Hydraulic properties. The present study also highlights the critical importance of AM fungal aquaporins in regulating Root Hydraulic properties of the host plant.
Beatriz Sánchez-Romera - One of the best experts on this subject based on the ideXlab platform.
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Techniques to Determine the Effects of Jasmonates on Root Hydraulic Conductivity.
Methods in molecular biology (Clifton N.J.), 2019Co-Authors: Beatriz Sánchez-Romera, Ricardo ArocaAbstract:Plants subjected to drought and saline stress conditions suffer from tissue dehydration. Such dehydration is caused by the imbalance between Root water uptake by Roots and water loss by transpiration. Therefore, determination of Root Hydraulic properties is crucial to understand plant water balance. Root Hydraulic Conductivity (L) can be used to estimate Root water transport capacity. L depends on Root architecture (length and diameter of the Root and proliferation of secondary Roots), radial water transport pathway (Root xylem vessels, plasmodesmata, apoplastic space, caspary bands), and on intrinsic membrane permeability to water (aquaporins, water membrane protein channels). Different methods have been developed to measure L, such as Pressure Chamber, Free Exudation, High-Pressure Flowmeter (HPFM), and Root Pressure Probe (RPP). In this chapter, we will focus on Pressure Chamber, Free Exudation, and HPFM methods which have been used to determine the effect of jasmonates (JA) on Root Hydraulic Conductivity.
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Arbuscular mycorrhizal symbiosis and methyl jasmonate avoid the inhibition of Root Hydraulic Conductivity caused by drought
Mycorrhiza, 2016Co-Authors: Beatriz Sánchez-Romera, Angel M. Zamarreño, José-maria Garcia-mina, Juan Manuel Ruiz-lozano, Ricardo ArocaAbstract:Hormonal regulation and symbiotic relationships provide benefits for plants to overcome stress conditions. The aim of this study was to elucidate the effects of exogenous methyl jasmonate (MeJA) application on Root Hydraulic Conductivity (L) of Phaseolus vulgaris plants which established arbuscular mycorrhizal (AM) symbiosis under two water regimes (well-watered and drought conditions). The variation in endogenous contents of several hormones (MeJA, JA, abscisic acid (ABA), indol-3-acetic acid (IAA), salicylic acid (SA)) and the changes in aquaporin gene expression, protein abundance and phosphorylation state were analyzed. AM symbiosis decreased L under well-watered conditions, which was partially reverted by the MeJA treatment, apparently by a drop in Root IAA contents. Also, AM symbiosis and MeJA prevented inhibition of L under drought conditions, most probably by a reduction in Root SA contents. Additionally, the gene expression of two fungal aquaporins was upregulated under drought conditions, independently of the MeJA treatment. Plant aquaporin gene expression could not explain the behaviour of L. Conversely, evidence was found for the control of L by phosphorylation of aquaporins. Hence, MeJA addition modified the response of L to both AM symbiosis and drought, presumably by regulating the Root contents of IAA and SA and the phosphorylation state of aquaporins.
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Exploring the use of recombinant inbred lines in combination with beneficial microbial inoculants (AM fungus and PGPR) to improve drought stress tolerance in tomato
Environmental and Experimental Botany, 2016Co-Authors: Maria Monica Calvo-polanco, Beatriz Sánchez-Romera, Ian C. Dodd, Ricardo Aroca Alvarez, Maria Jose Asins, Stephane Declerck, Cristina Martinez-andujar, Alfonso Albacete, Juan Manuel Ruiz-lozanoAbstract:At a world scale, tomato is an important horticultural crop, but its productivity is highly reduced by drought stress. Combining the application of beneficial microbial inoculants with breeding and grafting techniques may be key to cope with reduced tomato yield under drought. This study aimed to investigate the growth responses and physiological mechanisms involved in the performance under drought stress of four tomato recombinant inbred lines (RIL) after inoculation with the arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis and the plant growth promoting rhizobacteria (PGPR) Variovorax paradoxus 5C-2. Results showed a variation in the efficiency of the different tomato RILs under drought stress and a differential effect of the microbial inoculants, depending on the RIL involved. The inoculants affected plant parameters such as net photosynthetic capacity, oxidative damage to lipids, osmolyte accumulation, Root Hydraulic Conductivity or aquaporin abundance and phosphorylation status. RIL66 was the one obtaining maximum benefit from the microbial inoculants under drought stress conditions, due likely to improved CO2-fixation capacity and Root Hydraulic Conductivity. We propose that RIL66 could be selected as a good plant material to be used as Rootstock to improve tomato growth and productivity under water limiting conditions. Since RIL66 is highly responsive to microbial inoculants, this grafting strategy should be combined with inoculation of R. irregularis and V. paradoxus in order to improve plant yield under conditions of drought stress. (C) 2016 Elsevier B.V. All rights reserved.
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Exploring the use of recombinant inbred lines in combination with beneficial microbial inoculants (AM fungus and PGPR) to improve drought stress tolerance in tomato
Environmental and Experimental Botany, 2016Co-Authors: Mónica Calvo-polanco, Beatriz Sánchez-Romera, Ricardo Aroca, Ian C. Dodd, Stephane Declerck, Cristina Martinez-andujar, Alfonso Albacete, M. J. Asins, Juan Manuel Ruiz-lozanoAbstract:At a world scale, tomato is an important horticultural crop, but its productivity is highly reduced by drought stress. Combining the application of beneficial microbial inoculants with breeding and grafting techniques may be key to cope with reduced tomato yield under drought. This study aimed to investigate the growth responses and physiological mechanisms involved in the performance under drought stress of four tomato recombinant inbred lines (RIL) after inoculation with the arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis and the plant growth promoting rhizobacteria (PGPR) Variovorax paradoxus 5C-2. Results showed a variation in the efficiency of the different tomato RILs under drought stress and a differential effect of the microbial inoculants, depending on the RIL involved. The inoculants affected plant parameters such as net photosynthetic capacity, oxidative damage to lipids, osmolyte accumulation, Root Hydraulic Conductivity or aquaporin abundance and phosphorylation status. RIL66 was the one obtaining maximum benefit from the microbial inoculants under drought stress conditions, due likely to improved CO2-fixation capacity and Root Hydraulic Conductivity. We propose that RIL66 could be selected as a good plant material to be used as Rootstock to improve tomato growth and productivity under water limiting conditions. Since RIL66 is highly responsive to microbial inoculants, this grafting strategy should be combined with inoculation of R. irregularis and V. paradoxus in order to improve plant yield under conditions of drought stress.[EN]This research has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 289365 (RootOPOWER project).Peer reviewe
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Enhancement of Root Hydraulic Conductivity by methyl jasmonate and the role of calcium and abscisic acid in this process.
Plant Cell and Environment, 2014Co-Authors: Beatriz Sánchez-Romera, Angel M. Zamarreño, José-maria Garcia-mina, Juan Manuel Ruiz-lozano, Micaela Carvajal, Doan-trung Luu, Maria Del Carmen Martínez-ballesta, Christophe Maurel, Ricardo ArocaAbstract:The role of jasmonic acid in the induction of stomatal closure is well known. However, its role in regulating Root Hydraulic Conductivity (L) has not yet been explored. The objectives of the present research were to evaluate how JA regulates L and how calcium and abscisic acid (ABA) could be involved in such regulation. We found that exogenous methyl jasmonate (MeJA) increased L of Phaseolus vulgaris, Solanum lycopersicum and Arabidopsis thaliana Roots. Tomato plants defective in JA biosynthesis had lower values of L than wild-type plants, and that L was restored by addition of MeJA. The increase of L by MeJA was accompanied by an increase of the phosphorylation state of the aquaporin PIP2. We observed that MeJA addition increased the concentration of cytosolic calcium and that calcium channel blockers inhibited the rise of L caused by MeJA. Treatment with fluoridone, an inhibitor of ABA biosynthesis, partially inhibited the increase of L caused by MeJA, and tomato plants defective in ABA biosynthesis increased their L after application of MeJA. It is concluded that JA enhances L and that this enhancement is linked to calcium and ABA dependent and independent signalling pathways.
Maki Katsuhara - One of the best experts on this subject based on the ideXlab platform.
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exogenous application of abscisic acid aba increases Root and cell Hydraulic Conductivity and abundance of some aquaporin isoforms in the aba deficient barley mutant az34
Annals of Botany, 2016Co-Authors: G. V. Sharipova, Maki Katsuhara, Ian C. Dodd, Igor Ivanov, Wieland Fricke, Dmitriy Veselov, Takuya Furuichi, G R Kudoyarova, Stanislav Yu. VeselovAbstract:Background and Aims Regulation of water channel aquaporins (AQPs) provides another mechanism by which abscisic acid (ABA) may influence water flow through plants. To the best of our knowledge, no studies have addressed the changes in ABA levels, the abundance of AQPs and Root cell Hydraulic Conductivity (Lp(Cell)) in the same tissues. Thus, we followed the mechanisms by which ABA affects Root Hydraulics in an ABA-deficient barley mutant Az34 and its parental line 'Steptoe'. We compared the abundance of AQPs and ABA in cells to determine spatial correlations between AQP abundance and local ABA concentrations in different Root tissues. In addition, abundance of AQPs and ABA in cortex cells was related to Lp(Cell). Methods Root Hydraulic Conductivity (Lp(Root)) was measured by means of Root exudation analyses and Lp(Cell) using a cell pressure probe. The abundance of ABA and AQPs in Root tissues was assessed through immunohistochemical analyses. Isoform-specific antibodies raised against HvPIP2; 1, HvPIP2; 2 and HvPIP2; 5 were used. Key Results Immunolocalization revealed lower ABA levels in Root tissues of Az34 compared with ` Steptoe'. Root Hydraulic Conductivity (Lp(Root)) was lower in Az34, yet the abundance of HvPIPs in Root tissues was similar in the two genotypes. Root hair formation occurred closer to the tip, while the length of the Root hair zone was shorter in Az34 than in ` Steptoe'. Application of external ABA to the Root medium of Az34 and ` Steptoe' increased the immunostaining of Root cells for ABA and for HvPIP2; 1 and HvPIP2; 2 especially in Root epidermal cells and the cortical cell layer located beneath, parallel to an increase in Lp(Root) and Lp(Cell). Treatment of Roots with Fenton reagent, which inhibits AQP activity, prevented the ABA-induced increase in Root Hydraulic Conductivity. Conclusion Shortly after (<2 h) ABA application to the Roots of ABA-deficient barley, increased tissue ABA concentrations and AQP abundance (especially the plasma-membrane localized isoforms HvPIP2;1 and HvPIP2;2) were spatially correlated in Root epidermal cells and the cortical cell layer located beneath, in conjunction with increased LpCell of the cortical cells. In contrast, long-term ABA deficiency throughout seedling development affects Root Hydraulics through other mechanisms, in particular the developmental timing of the formation of Root hairs closer to the Root tip and the length of the Root hair zone.
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Exogenous application of abscisic acid (ABA) increases Root and cell Hydraulic Conductivity and abundance of some aquaporin isoforms in the ABA-deficient barley mutant Az34
Annals of botany, 2016Co-Authors: G. V. Sharipova, Maki Katsuhara, Ian C. Dodd, Igor Ivanov, Guzel R. Kudoyarova, Wieland Fricke, Dmitriy Veselov, Takuya Furuichi, Stanislav Yu. VeselovAbstract:Background and Aims Regulation of water channel aquaporins (AQPs) provides another mechanism by which abscisic acid (ABA) may influence water flow through plants. To the best of our knowledge, no studies have addressed the changes in ABA levels, the abundance of AQPs and Root cell Hydraulic Conductivity (LpCell) in the same tissues. Thus, we followed the mechanisms by which ABA affects Root Hydraulics in an ABA-deficient barley mutant Az34 and its parental line 'Steptoe'. We compared the abundance of AQPs and ABA in cells to determine spatial correlations between AQP abundance and local ABA concentrations in different Root tissues. In addition, abundance of AQPs and ABA in cortex cells was related to LpCell. Methods Root Hydraulic Conductivity (LpRoot) was measured by means of Root exudation analyses and LpCell using a cell pressure probe. The abundance of ABA and AQPs in Root tissues was assessed through immunohistochemical analyses. Isoform-specific antibodies raised against HvPIP2;1, HvPIP2;2 and HvPIP2;5 were used. Key Results Immunolocalization revealed lower ABA levels in Root tissues of Az34 compared with 'Steptoe'. Root Hydraulic Conductivity (LpRoot) was lower in Az34, yet the abundance of HvPIPs in Root tissues was similar in the two genotypes. Root hair formation occurred closer to the tip, while the length of the Root hair zone was shorter in Az34 than in 'Steptoe'. Application of external ABA to the Root medium of Az34 and 'Steptoe' increased the immunostaining of Root cells for ABA and for HvPIP2;1 and HvPIP2;2 especially in Root epidermal cells and the cortical cell layer located beneath, parallel to an increase in LpRoot and LpCell. Treatment of Roots with Fenton reagent, which inhibits AQP activity, prevented the ABA-induced increase in Root Hydraulic Conductivity. Conclusion Shortly after (
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dynamic regulation of the Root Hydraulic Conductivity of barley plants in response to salinity osmotic stress
Plant and Cell Physiology, 2015Co-Authors: Toshiyuki Kaneko, Mineko Shibasaka, Tomoaki Horie, Yoshiki Nakahara, Nobuya Tsuji, Maki KatsuharaAbstract:Salinity stress significantly reduces the Root Hydraulic Conductivity (Lpr) of several plant species including barley (Hordeum vulgare). Here we characterized changes in the Lpr of barley plants in response to salinity/osmotic stress in detail using a pressure chamber. Salt-tolerant and intermediate barley cultivars, K305 and Haruna-nijyo, but not a salt-sensitive cultivar, I743, exhibited characteristic time-dependent Lpr changes induced by 100 mM NaCl. An identical response was evoked by isotonic sorbitol, indicating that this phenomenon was triggered by osmotic imbalances. Further examination of this mechanism using barley cv. Haruna-nijyo plants in combination with the use of various inhibitors suggested that various cellular processes such as protein phosphorylation/dephosphorylation and membrane internalization appear to be involved. Interestingly, the three above-mentioned barley cultivars did not exhibit a remarkable difference in Root cell sap osmolality under hypertonic conditions, in contrast to the case of Lpr. The possible biological significance of the regulation of Lpr in barley plants upon salinity/osmotic stress is discussed.
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Dynamic Regulation of the Root Hydraulic Conductivity of Barley Plants in Response to Salinity/Osmotic Stress
Plant & cell physiology, 2015Co-Authors: Toshiyuki Kaneko, Mineko Shibasaka, Tomoaki Horie, Yoshiki Nakahara, Nobuya Tsuji, Maki KatsuharaAbstract:Salinity stress significantly reduces the Root Hydraulic Conductivity (Lpr) of several plant species including barley (Hordeum vulgare). Here we characterized changes in the Lpr of barley plants in response to salinity/osmotic stress in detail using a pressure chamber. Salt-tolerant and intermediate barley cultivars, K305 and Haruna-nijyo, but not a salt-sensitive cultivar, I743, exhibited characteristic time-dependent Lpr changes induced by 100 mM NaCl. An identical response was evoked by isotonic sorbitol, indicating that this phenomenon was triggered by osmotic imbalances. Further examination of this mechanism using barley cv. Haruna-nijyo plants in combination with the use of various inhibitors suggested that various cellular processes such as protein phosphorylation/dephosphorylation and membrane internalization appear to be involved. Interestingly, the three above-mentioned barley cultivars did not exhibit a remarkable difference in Root cell sap osmolality under hypertonic conditions, in contrast to the case of Lpr. The possible biological significance of the regulation of Lpr in barley plants upon salinity/osmotic stress is discussed.
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barley Root Hydraulic Conductivity and aquaporins expression in relation to salt tolerance
Soil Science and Plant Nutrition, 2007Co-Authors: Maki Katsuhara, Mineko ShibasakaAbstract:Root Hydraulic Conductivity (Lpr) and aquaporins were investigated in barley seedlings under salt stress of 100 mmol L−1 NaCl in hydroponic culture for 24 and 48 h. No reduction in Root elongation was observed in stressed seedlings, and more that 75% of Root and shoot growth was maintained under salt stress of 100 mmol L−1 NaCl. A slight increase in HvPIP2;1 transcript, which was the most abundant of the three aquaporins investigated, was observed. No significant changes in Lpr and HvPIP2;1 protein were detected. The possible reason for these complicated results and the function of aquaporins in Lpr under salt stress are discussed.
