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Ramasubbu Sankararamakrishnan - One of the best experts on this subject based on the ideXlab platform.
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genome wide analysis of major intrinsic proteins in the Tree Plant populus trichocarpa characterization of xip subfamily of aquaporins from evolutionary perspective
BMC Plant Biology, 2009Co-Authors: Anjali Gupta, Ramasubbu SankararamakrishnanAbstract:Background Members of major intrinsic proteins (MIPs) include water-conducting aquaporins and glycerol-transporting aquaglyceroporins. MIPs play important role in Plant-water relations. The model Plants Arabidopsis thaliana, rice and maize contain more than 30 MIPs and based on phylogenetic analysis they can be divided into at least four subfamilies. Populus trichocarpa is a model Tree species and provides an opportunity to investigate several Tree-specific traits. In this study, we have investigated Populus MIPs (PtMIPs) and compared them with their counterparts in Arabidopsis, rice and maize.
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genome wide analysis of major intrinsic proteins in the Tree Plant populus trichocarpa characterization of xip subfamily of aquaporins from evolutionary perspective
BMC Plant Biology, 2009Co-Authors: Anjali Gupta, Ramasubbu SankararamakrishnanAbstract:Members of major intrinsic proteins (MIPs) include water-conducting aquaporins and glycerol-transporting aquaglyceroporins. MIPs play important role in Plant-water relations. The model Plants Arabidopsis thaliana, rice and maize contain more than 30 MIPs and based on phylogenetic analysis they can be divided into at least four subfamilies. Populus trichocarpa is a model Tree species and provides an opportunity to investigate several Tree-specific traits. In this study, we have investigated Populus MIPs (PtMIPs) and compared them with their counterparts in Arabidopsis, rice and maize. Fifty five full-length MIPs have been identified in Populus genome. Phylogenetic analysis reveals that Populus has a fifth uncharacterized subfamily (XIPs). Three-dimensional models of all 55 PtMIPs were constructed using homology modeling technique. Aromatic/arginine (ar/R) selectivity filters, characteristics of loops responsible for solute selectivity (loop C) and gating (loop D) and group conservation of small and weakly polar interfacial residues have been analyzed. Majority of the non-XIP PtMIPs are similar to those in Arabidopsis, rice and maize. Additional XIPs were identified from database search and 35 XIP sequences from dicots, fungi, moss and protozoa were analyzed. Ar/R selectivity filters of dicots XIPs are more hydrophobic compared to fungi and moss XIPs and hence they are likely to transport hydrophobic solutes. Loop C is longer in one of the subgroups of dicot XIPs and most probably has a significant role in solute selectivity. Loop D in dicot XIPs has higher number of basic residues. Intron loss is observed on two occasions: once between two subfamilies of eudicots and monocot and in the second instance, when dicot and moss XIPs diverged from fungi. Expression analysis of Populus MIPs indicates that Populus XIPs don't show any tissue-specific transcript abundance. Due to whole genome duplication, Populus has the largest number of MIPs identified in any single species. Non-XIP MIPs are similar in all four Plant species considered in this study. Small and weakly polar residues at the helix-helix interface are group conserved presumably to maintain the hourglass fold of MIP channels. Substitutions in ar/R selectivity filter, insertion/deletion in loop C, increasing basic nature of loop D and loss of introns are some of the events occurred during the evolution of dicot XIPs.
Anjali Gupta - One of the best experts on this subject based on the ideXlab platform.
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genome wide analysis of major intrinsic proteins in the Tree Plant populus trichocarpa characterization of xip subfamily of aquaporins from evolutionary perspective
BMC Plant Biology, 2009Co-Authors: Anjali Gupta, Ramasubbu SankararamakrishnanAbstract:Background Members of major intrinsic proteins (MIPs) include water-conducting aquaporins and glycerol-transporting aquaglyceroporins. MIPs play important role in Plant-water relations. The model Plants Arabidopsis thaliana, rice and maize contain more than 30 MIPs and based on phylogenetic analysis they can be divided into at least four subfamilies. Populus trichocarpa is a model Tree species and provides an opportunity to investigate several Tree-specific traits. In this study, we have investigated Populus MIPs (PtMIPs) and compared them with their counterparts in Arabidopsis, rice and maize.
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genome wide analysis of major intrinsic proteins in the Tree Plant populus trichocarpa characterization of xip subfamily of aquaporins from evolutionary perspective
BMC Plant Biology, 2009Co-Authors: Anjali Gupta, Ramasubbu SankararamakrishnanAbstract:Members of major intrinsic proteins (MIPs) include water-conducting aquaporins and glycerol-transporting aquaglyceroporins. MIPs play important role in Plant-water relations. The model Plants Arabidopsis thaliana, rice and maize contain more than 30 MIPs and based on phylogenetic analysis they can be divided into at least four subfamilies. Populus trichocarpa is a model Tree species and provides an opportunity to investigate several Tree-specific traits. In this study, we have investigated Populus MIPs (PtMIPs) and compared them with their counterparts in Arabidopsis, rice and maize. Fifty five full-length MIPs have been identified in Populus genome. Phylogenetic analysis reveals that Populus has a fifth uncharacterized subfamily (XIPs). Three-dimensional models of all 55 PtMIPs were constructed using homology modeling technique. Aromatic/arginine (ar/R) selectivity filters, characteristics of loops responsible for solute selectivity (loop C) and gating (loop D) and group conservation of small and weakly polar interfacial residues have been analyzed. Majority of the non-XIP PtMIPs are similar to those in Arabidopsis, rice and maize. Additional XIPs were identified from database search and 35 XIP sequences from dicots, fungi, moss and protozoa were analyzed. Ar/R selectivity filters of dicots XIPs are more hydrophobic compared to fungi and moss XIPs and hence they are likely to transport hydrophobic solutes. Loop C is longer in one of the subgroups of dicot XIPs and most probably has a significant role in solute selectivity. Loop D in dicot XIPs has higher number of basic residues. Intron loss is observed on two occasions: once between two subfamilies of eudicots and monocot and in the second instance, when dicot and moss XIPs diverged from fungi. Expression analysis of Populus MIPs indicates that Populus XIPs don't show any tissue-specific transcript abundance. Due to whole genome duplication, Populus has the largest number of MIPs identified in any single species. Non-XIP MIPs are similar in all four Plant species considered in this study. Small and weakly polar residues at the helix-helix interface are group conserved presumably to maintain the hourglass fold of MIP channels. Substitutions in ar/R selectivity filter, insertion/deletion in loop C, increasing basic nature of loop D and loss of introns are some of the events occurred during the evolution of dicot XIPs.
Léon Wehrlen - One of the best experts on this subject based on the ideXlab platform.
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Tree regeneration and Plant species diversity responses to vegetation control following a major windthrow in mixed broadleaved stands
European Journal of Forest Research, 2011Co-Authors: Marine Dodet, Catherine Collet, Henri Frochot, Léon WehrlenAbstract:By increasing resource availability, canopy opening enhances Tree recruitment as well as the development of neighbouring vegetation. The proliferation of early successional and highly competitive vegetation may have dramatic consequences on seedling establishment. However, differences in competitive abilities have been shown among the Plant growth forms commonly encountered in forests. We may thus expect that vegetation management leading to control of different Plant growth forms would have different consequences on Tree seedling growth and development. To test this hypothesis, we analysed the effects of an intensity gradient of four vegetation control treatments (untreated, coppice control, coppice and non-Tree Plant control, and coppice, non-Tree and pioneer (Tree) Plant control) on Plant species richness and natural Tree regeneration in three post-storm sites. Higher Plant species richness and a better natural Tree regeneration were observed in the more intensive treatments that significantly improved the balance of the relative abundance of Tree species. Suppressing the more competitive vegetation, mainly Rubus fruticosus and graminoids, led to the recruitment and growth of Tree species sensitive to competition and good Tree species diversity. Practical recommendations in terms of vegetation control relative to Tree regeneration and Plant species richness are given.
I Gouttevin - One of the best experts on this subject based on the ideXlab platform.
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how the insulating properties of snow affect soil carbon distribution in the continental pan arctic area
Journal of Geophysical Research, 2012Co-Authors: I Gouttevin, Martin Menegoz, Florent Domine, Gerhard Krinner, Charles D Koven, P Ciais, Charles TarnocaiAbstract:[1] We demonstrate the effect of an ecosystem differentiated insulation by snow on the soil thermal regime and on the terrestrial soil carbon distribution in the pan-Arctic area. This is done by means of a sensitivity study performed with the land surface model ORCHIDEE, which furthermore provides a first quantification of this effect. Based on field campaigns reporting higher thermal conductivities and densities for the tundra snowpack than for taiga snow, two distributions of near-equilibrium soil carbon stocks are computed, one relying on uniform snow thermal properties and the other using ecosystem-differentiated snow thermal properties. Those modeled distributions strongly depend on soil temperature through decomposition processes. Considering higher insulation by snow in taiga areas induces warmer soil temperatures by up to 12 K in winter at 50 cm depth. This warmer soil signal persists over summer with a temperature difference of up to 4 K at 50 cm depth, especially in areas exhibiting a thick, enduring snow cover. These thermal changes have implications on the modeled soil carbon stocks, which are reduced by 8% in the pan-Arctic continental area when the vegetation-induced variations of snow thermal properties are accounted for. This is the result of diverse and spatially heterogeneous ecosystem processes: where higher soil temperatures lift nitrogen limitation on Plant productivity, Tree Plant functional types thrive whereas light limitation and enhanced water stress are the new constrains on lower vegetation, resulting in a reduced net productivity at the pan-Arctic scale. Concomitantly, higher soil temperatures yield increased respiration rates (+22% over the study area) and result in reduced permafrost extent and deeper active layers which expose greater volumes of soil to microbial decomposition. The three effects combine to produce lower soil carbon stocks in the pan-Arctic terrestrial area. Our study highlights the role of snow in combination with vegetation in shaping the distribution of soil carbon and permafrost at high latitudes.
Didier Le Thiec - One of the best experts on this subject based on the ideXlab platform.
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New flux based dose-response relationships for ozone for European forest Tree species
Environmental Pollution, 2015Co-Authors: P. Büker, Z. Feng, J. Uddling, A. Briolat, R. Alonso, S. Braun, S. Elvira, G Gerosa, P.e. Karlsson, Didier Le ThiecAbstract:To derive O3 dose-response relationships (DRR) for five European forest Trees species and broadleaf deciduous and needleleaf Tree Plant functional types (PFTs), phytotoxic O3 doses (PODy) were related to biomass reductions.[br/] PODy was calculated using a stomatal flux model with a range of cut-off thresholds (y) indicative of varying detoxification capacities. Linear regression analysis showed that DRR for PFT and individual Tree species differed in their robustness. A simplified parameterisation of the flux model was tested and showed that for most non-Mediterranean Tree species, this simplified model led to similarly robust DRR as compared to a species- and climate region-specific parameterisation.[br/] Experimentally induced soil water stress was not found to substantially reduce PODy, mainly due to the short duration of soil water stress periods.[br/] This study validates the stomatal O3 flux concept and represents a step forward in predicting O3 damage to forests in a spatially and temporally varying climate.
