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Alexandra Girondé - One of the best experts on this subject based on the ideXlab platform.
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the contrasting n management of two oilseed rape genotypes reveals the mechanisms of proteolysis associated with leaf n Remobilization and the respective contributions of leaves and stems to n storage and Remobilization during seed filling
BMC Plant Biology, 2015Co-Authors: Alexandra Girondé, Philippe Etienne, Jacques Trouverie, Alain Bouchereau, Françoise Le Cahérec, Laurent Leport, Mathilde OrselAbstract:Oilseed rape is the third largest oleaginous crop in the world but requires high levels of N fertilizer of which only 50% is recovered in seeds. This weak N use efficiency is associated with a low foliar N Remobilization, leading to a significant return of N to the soil and a risk of pollution. Contrary to what is observed during senescence in the vegetative stages, N Remobilization from stems and leaves is considered efficient during monocarpic senescence. However, the contribution of stems towards N management and the cellular mechanisms involved in foliar Remobilization remain largely unknown. To reach this goal, the N fluxes at the whole plant level from bolting to mature seeds and the processes involved in leaf N Remobilization and proteolysis were investigated in two contrasting genotypes (Aviso and Oase) cultivated under ample or restricted nitrate supply. During seed filling in both N conditions, Oase efficiently allocated the N from uptake to seeds while Aviso favoured a better N Remobilization from stems and leaves towards seeds. Nitrate restriction decreased seed yield and oil quality for both genotypes but Aviso had the best seed N filling. Under N limitation, Aviso had a better N Remobilization from leaves to stems before the onset of seed filling. Afterwards, the higher N Remobilization from stems and leaves of Aviso led to a higher final N amount in seeds. This high leaf N Remobilization is associated with a better degradation/export of insoluble proteins, oligopeptides, nitrate and/or ammonia. By using an original method based on the determination of Rubisco degradation in the presence of inhibitors of proteases, efficient proteolysis associated with cysteine proteases and proteasome activities was identified as the mechanism of N Remobilization. The results confirm the importance of foliar N Remobilization after bolting to satisfy seed filling and highlight that an efficient proteolysis is mainly associated with (i) cysteine proteases and proteasome activities and (ii) a fine coordination between proteolysis and export mechanisms. In addition, the stem may act as transient storage organs in the case of an asynchronism between leaf N Remobilization and N demand for seed filling.
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The contrasting N management of two oilseed rape genotypes reveals the mechanisms of proteolysis associated with leaf N Remobilization and the respective contributions of leaves and stems to N storage and Remobilization during seed filling.
BMC Plant Biology, 2015Co-Authors: Alexandra Girondé, Philippe Etienne, Jacques Trouverie, Alain Bouchereau, Françoise Le Cahérec, Laurent Leport, Mathilde Orsel, Marie-françoise Niogret, Nathalie Nesi, Fabienne SoulayAbstract:Oilseed rape is the third largest oleaginous crop in the world but requires high levels of N fertilizer of which only 50% is recovered in seeds. This weak N use efficiency is associated with a low foliar N Remobilization, leading to a significant return of N to the soil and a risk of pollution. Contrary to what is observed during senescence in the vegetative stages, N Remobilization from stems and leaves is considered efficient during monocarpic senescence. However, the contribution of stems towards N management and the cellular mechanisms involved in foliar Remobilization remain largely unknown. To reach this goal, the N fluxes at the whole plant level from bolting to mature seeds and the processes involved in leaf N Remobilization and proteolysis were investigated in two contrasting genotypes (Aviso and Oase) cultivated under ample or restricted nitrate supply. Results: During seed filling in both N conditions, Oase efficiently allocated the N from uptake to seeds while Aviso favoured a better N Remobilization from stems and leaves towards seeds. Nitrate restriction decreased seed yield and oil quality for both genotypes but Aviso had the best seed N filling. Under N limitation, Aviso had a better N Remobilization from leaves to stems before the onset of seed filling. Afterwards, the higher N Remobilization from stems and leaves of Aviso led to a higher final N amount in seeds. This high leaf N Remobilization is associated with a better degradation/export of insoluble proteins, oligopeptides, nitrate and/or ammonia. By using an original method based on the determination of Rubisco degradation in the presence of inhibitors of proteases, efficient proteolysis associated with cysteine proteases and proteasome activities was identified as the mechanism of N Remobilization. Conclusion: The results confirm the importance of foliar N Remobilization after bolting to satisfy seed filling and highlight that an efficient proteolysis is mainly associated with (i) cysteine proteases and proteasome activities and (ii) a fine coordination between proteolysis and export mechanisms. In addition, the stem may act as transient storage organs in the case of an asynchronism between leaf N Remobilization and N demand for seed filling.
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A profiling approach of the natural variability of foliar N Remobilization at the rosette stage gives clues to understand the limiting processes involved in the low N use efficiency of winter oilseed rape
Journal of Experimental Botany, 2015Co-Authors: Alexandra Girondé, Philippe Etienne, Jacques Trouverie, Alain Bouchereau, Françoise Le Cahérec, Laurent Leport, Marie-françoise Niogret, Marine Poret, Mathilde Orsel Baldwin, Carole DeleuAbstract:Oilseed rape, a crop requiring a high level of nitogen (N) fertilizers, is characterized by low N use efficiency. To identify the limiting factors involved in the N use efficiency of winter oilseed rape, the response to low N supply was investigated at the vegetative stage in 10 genotypes by using long-term pulse-chase (15)N labelling and studying the physiological processes of leaf N Remobilization. Analysis of growth and components of N use efficiency allowed four profiles to be defined. Group 1 was characterized by an efficient N Remobilization under low and high N conditions but by a decrease of leaf growth under N limitation. Group 2 showed a decrease in leaf growth under low N supply that was associated with a low N Remobilization efficiency under both N supplies despite a high Remobilization of soluble proteins. In response to N limitation, Group 3 is characterized by an increase in N use efficiency and leaf N Remobilization compared with high N that is not sufficient to sustain the leaf biomass production at a similar level to non-limited plants. Genotypes of Group 4 subjected to low nitrate were able to maintain leaf growth to the same level as under high N. The profiling approach indicated that enhancement of amino acid export and soluble protein degradation was crucial for N Remobilization improvement. At the whole-plant level, N fluxes revealed that Group 4 showed a high N Remobilization in source leaves combined with a better N utilization in young leaves. Consequently, an enhanced N Remobilization limits N loss in fallen leaves, but this remobilized N needs to be efficiently utilized in young leaves to improve N use efficiency.
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The impact of sulfate restriction on seed yield and quality of winter oilseed rape depends on the ability to remobilize sulfate from vegetative tissues to reproductive organs
Frontiers in Plant Science, 2014Co-Authors: Alexandra Girondé, Philippe Etienne, Jacques Trouverie, Lucie Dubousset, Jean Christophe AviceAbstract:Our current knowledge about sulfur(S) management by winter oilseed rape to satisfy the S demand of developing seeds is still scarce, particularly in relation to S restriction. Our goals were to determine the physiological processes related to S use efficiency that led to maintain the seed yield and quality when S limitation occurred at the bolting or early flowering stages. To address these questions, a pulse-chase (SO42-)-S-34 labeling method was carried out in order to study the S fluxes from uptake and Remobilization at the whole plant level. In response of S limitation at the bolting or early flowering stages, the leaves are the most important source organ for S Remobilization during reproductive stages. By combining S-34-tracer with biochemical fractionation in order to separate sulfate from other S-compounds, it appeared that sulfate was the main form of S remobilized in leaves at reproductive stages and that tonoplastic SULTR4-type transporters were specifically involved in the sulfate remobilisation in case of low S availability. In response to S limitation at the bolting stage, the seed yield and quality were dramatically reduced compared to control plants. These data suggest that the increase of both S Remobilization from source leaves and the root proliferation in order to maximize sulfate uptake capacities, were not sufficient to maintain the seed yield and quality. When S limitation occurred at the early flowering stage, oilseed rape can optimize the mobilization of sulfate reserves from vegetative organs (leaves and stem) to satisfy the demand of seeds and maintain the seed yield and quality. Our study also revealed that the stem may act as a transient storage organ for remobilized S coming from source leaves before its utilization by seeds. The physiological traits (S Remobilization, root proliferation, transient S storage in stem) observed under S limitation could be used in breeding programs to select oilseed rape genotypes with high S use efficiency.
Jianhua Zhang - One of the best experts on this subject based on the ideXlab platform.
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comprehensive epigenome and transcriptome analysis of carbon reserve Remobilization in indica and japonica rice stems under moderate soil drying
Journal of Experimental Botany, 2021Co-Authors: Guanqun Wang, Jianhua ZhangAbstract:Moderate soil drying (MD) imposed at the post-anthesis stage significantly improves carbon reserve Remobilization in rice stems, increasing grain yield. However, the methylome and transcriptome profiles of carbon reserve Remobilization under MD are obscure in indica and japonica rice stems. Here, we generated whole-genome single-base resolution maps of the DNA methylome in indica and japonica rice stems. DNA methylation levels were higher in indica than in japonica and positively correlated with genome size. MD treatment had a weak impact on the changes in methylation levels in indica. Moreover, the number of differentially methylated regions was much lower in indica, indicating the existence of cultivar-specific methylation patterns in response to MD during grain filling. The gene encoding β-glucosidase 1, involved in the starch degradation process, was hypomethylated and up-regulated in indica, resulting in improved starch to sucrose conversion under MD treatment. Additionally, increased expression of MYBS1 transactivated the expression of AMYC2/OsAMY2A in both indica and japonica, leading to enhanced starch degradation under MD. In contrast, down-regulated expression of MYB30 resulted in increased expression of BMY5 in both cultivars. Our findings decode the dynamics of DNA methylation in indica and japonica rice stems and propose candidate genes for improving carbon reserve Remobilization.
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grain filling of cereals under soil drying
New Phytologist, 2006Co-Authors: Jianchang Yang, Jianhua ZhangAbstract:Contents Summary 223 I. Introduction 224 II. Problems in grain filling: unfavorably delayed whole-plant senescence 224 III. Controlled soil drying improves carbon Remobilization and grain filling as a result of enhanced whole-plant senescence 225 IV. Hormonal regulation of whole-plant senescence and grain filling 229 V. Activities of key enzymes involved in carbon Remobilization and grain filling 230 VI. Conclusions 232 Acknowledgements 232 References 232 Summary Monocarpic plants require the initiation of whole-plant senescence to remobilize and transfer assimilates pre-stored in vegetative tissues to grains. Delayed whole-plant senescence caused by either heavy use of nitrogen fertilizer or adoption of lodging-resistant cultivars/hybrids that remain green when the grains are due to ripen results in a low harvest index with much nonstructural carbohydrate (NSC) left in the straw. Usually, water stress during the grain-filling period induces early senescence, reduces photosynthesis, and shortens the grain-filling period; however, it increases the Remobilization of NSC from the vegetative tissues to the grain. If mild soil drying is properly controlled during the later grain-filling period in rice (Oryza sativa) and wheat (Triticum aestivum), it can enhance whole-plant senescence, lead to faster and better Remobilization of carbon from vegetative tissues to grains, and accelerate the grain-filling rate. In cases where plant senescence is unfavorably delayed, such as by heavy use of nitrogen and the introduction of hybrids with strong heterosis, the gain from the enhanced Remobilization and accelerated grain-filling rate can outweigh the loss of reduced photosynthesis and the shortened grain-filling period, leading to an increased grain yield, better harvest index and higher water-use efficiency.
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grain filling of cereals under soil drying
New Phytologist, 2006Co-Authors: Jianchang Yang, Jianhua ZhangAbstract:Monocarpic plants require the initiation of whole-plant senescence to remobilize and transfer assimilates pre-stored in vegetative tissues to grains. Delayed whole-plant senescence caused by either heavy use of nitrogen fertilizer or adoption of lodging-resistant cultivars/hybrids that remain green when the grains are due to ripen results in a low harvest index with much nonstructural carbohydrate (NSC) left in the straw. Usually, water stress during the grain-filling period induces early senescence, reduces photosynthesis, and shortens the grain-filling period; however, it increases the Remobilization of NSC from the vegetative tissues to the grain. If mild soil drying is properly controlled during the later grain-filling period in rice (Oryza sativa) and wheat (Triticum aestivum), it can enhance whole-plant senescence, lead to faster and better Remobilization of carbon from vegetative tissues to grains, and accelerate the grain-filling rate. In cases where plant senescence is unfavorably delayed, such as by heavy use of nitrogen and the introduction of hybrids with strong heterosis, the gain from the enhanced Remobilization and accelerated grain-filling rate can outweigh the loss of reduced photosynthesis and the shortened grain-filling period, leading to an increased grain yield, better harvest index and higher water-use efficiency.
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activities of fructan and sucrose metabolizing enzymes in wheat stems subjected to water stress during grain filling
Planta, 2004Co-Authors: Jianchang Yang, Jianhua Zhang, Zhiqing Wang, Qingsen Zhu, Lijun LiuAbstract:This study investigated if a controlled water deficit during grain filling of wheat (Triticum aestivum L.) could accelerate grain filling by facilitating the Remobilization of carbon reserves in the stem through regulating the enzymes involved in fructan and sucrose metabolism. Two high lodging-resistant wheat cultivars were grown in pots and treated with either a normal (NN) or high amount of nitrogen (HN) at heading time. Plants were either well-watered (WW) or water-stressed (WS) from 9 days post anthesis until maturity. Leaf water potentials markedly decreased at midday as a result of water stress but completely recovered by early morning. Photosynthetic rate and zeatin + zeatin riboside concentrations in the flag leaves declined faster in WS plants than in WW plants, and they decreased more slowly with HN than with NN when soil water potential was the same, indicating that the water deficit enhanced, whereas HN delayed, senescence. Water stress, both at NN and HN, facilitated the reduction in concentration of total nonstructural carbohydrates (NSC) and fructans in the stems but increased the sucrose level there, promoted the re-allocation of pre-fixed 14C from the stems to grains, shortened the grain-filling period, and accelerated the grain-filling rate. Grain weight and grain yield were increased under the controlled water deficit when HN was applied. Fructan exohydrolase (FEH; EC 3.2.1.80) and sucrose phosphate synthase (SPS; EC 2.4.1.14) activities were substantially enhanced by water stress and positively correlated with the total NSC and fructan Remobilization from the stems. Acid invertase (EC 3.2.1.26) activity was also enhanced by the water stress and associated with the change in fructan concentration, but not correlated with the total NSC Remobilization and 14C increase in the grains. Sucrose:sucrose fructosyltransferase (EC 2.4.1.99) activity was inhibited by the water stress and negatively correlated with the Remobilization of carbon reserves. Sucrose synthase (EC 2.4.1.13) activity in the stems decreased sharply during grain filling and showed no significant difference between WW and WS treatments. Abscisic acid (ABA) concentration in the stem was remarkably enhanced by water stress and significantly correlated with SPS and FEH activities. Application of ABA to WW plants yielded similar results to those for WS plants. The results suggest that the increased Remobilization of carbon reserves by water stress is attributable to the enhanced FEH and SPS activities in wheat stems, and that ABA plays a vital role in the regulation of the key enzymes involved in fructan and sucrose metabolism.
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involvement of abscisic acid and cytokinins in the senescence and Remobilization of carbon reserves in wheat subjected to water stress during grain filling
Plant Cell and Environment, 2003Co-Authors: Jianchang Yang, Jianhua Zhang, Zhiqing Wang, Q S Zhu, L J LiuAbstract:This study investigated the possibility that abscisic acid (ABA) and cytokinins may mediate the effect of water deficit that enhances plant senescence and Remobilization of pre-stored carbon reserves. Two high lodging-resistant wheat (Triticum aestivum L.) cultivars were field grown and treated with either a normal or high amount of nitrogen at heading. Well-watered (WW) and water-stressed (WS) treatments were imposed from 9 d post-anthesis until maturity. Chlorophyll (Chl) and photosynthetic rate (Pr) of the flag leaves declined faster in WS plants than in WW plants, indicating that the water deficit enhanced senescence. Water stress facilitated the reduction of non-structural carbohydrate in the stems and promoted the re-allocation of prefixed 14C from the stems to grains, shortened the grain filling period and increased the grain filling rate. Water stress substantially increased ABA but reduced zeatin (Z) + zeatin riboside (ZR) concentrations in the stems and leaves. ABA correlated significantly and negatively, whereas Z + ZR correlated positively, with Pr and Chl of the flag leaves. ABA but not Z + ZR, was positively and significantly correlated with Remobilization of pre-stored carbon and grain filling rate. Exogenous ABA reduced Chl in the flag leaves, enhanced the Remobilization, and increased grain filling rate. Spraying with kinetin had the opposite effect. The results suggest that both ABA and cytokinins are involved in controlling plant senescence, and an enhanced carbon Remobilization and accelerated grain filling rate are attributed to an elevated ABA level in wheat plants when subjected to water stress.
Jean Christophe Avice - One of the best experts on this subject based on the ideXlab platform.
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proteomic investigations of proteases involved in cotyledon senescence a model to explore the genotypic variability of proteolysis machinery associated with nitrogen Remobilization efficiency during the leaf senescence of oilseed rape
Proteome, 2017Co-Authors: Marine Poret, Laurent Coquet, Thierry Jouenne, Balakumaran Chandrasekar, R A L Van Der Hoorn, Jean Christophe AviceAbstract:Oilseed rape is characterized by a low nitrogen Remobilization efficiency during leaf senescence, mainly due to a lack of proteolysis. Because cotyledons are subjected to senescence, it was hypothesized that contrasting protease activities between genotypes may be distinguishable early in the senescence of cotyledons. To verify this assumption, our goals were to (i) characterize protease activities in cotyledons between two genotypes with contrasting nitrogen Remobilization efficiency (Tenor and Samourai) under limiting or ample nitrate supply; and (ii) test the role of salicylic acid (SA) and abscisic acid (ABA) in proteolysis regulation. Protease activities were measured and identified by a proteomics approach combining activity-based protein profiling with LC-MS/MS. As in senescing leaves, chlorophyll and protein contents decrease in senescing cotyledons and are correlated with an increase in serine and cysteine protease activities. Two RD21-like and SAG-12 proteases previously associated with an efficient proteolysis in senescing leaves of Tenor are also detected in senescing cotyledons. The infiltration of ABA and SA provokes the induction of senescence and several cysteine and serine protease activities. The study of protease activities during the senescence of cotyledons seems to be a promising experimental model to investigate the regulation and genotypic variability of proteolysis associated with efficient N Remobilization.
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Characterization of senescence-associated protease activities involved in the efficient protein Remobilization during leaf senescence of winter oilseed rape
Plant Science, 2016Co-Authors: Marine Poret, Balakumaran Chandrasekar, Renier A.l. Van Der Hoorn, Jean Christophe AviceAbstract:Oilseed rape (Brassica napus L.) is a crop plant characterized by a poor nitrogen (N) use efficiency that is mainly due to low N Remobilization efficiency during the sequential leaf senescence of the vegetative stage. As a high leaf N Remobilization efficiency was strongly linked to a high Remobilization of proteins during leaf senescence of rapeseed, our objective was to identify senescence-associated protease activities implicated in the protein degradation. To reach this goal, leaf senescence processes and protease activities were investigated in a mature leaf becoming senescent in plants subjected to ample or low nitrate supply. The characterization of protease activities was performed by using in vitro analysis of RuBisCO degradation with or without inhibitors of specific protease classes followed by a protease activity profiling using activity-dependent probes. As expected, the mature leaf became senescent regardless of the nitrate treatment, and nitrate limitation enhanced the senescence processes associated with an enhanced degradation of soluble proteins. The characterization of protease activities revealed that: (i) aspartic proteases and the proteasome were active during senescence regardless of nitrate supply, and (ii) the activities of serine proteases and particularly cysteine proteases (Papain-like Cys proteases and vacuolar processing enzymes) increased when protein Remobilization associated with senescence was accelerated by nitrate limitation. Short statement: Serine and particularly cysteine proteases (both PLCPs and VPEs) seem to play a crucial role in the efficient protein Remobilization when leaf senescence of oilseed rape was accelerated by nitrate limitation.
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The impact of sulfate restriction on seed yield and quality of winter oilseed rape depends on the ability to remobilize sulfate from vegetative tissues to reproductive organs
Frontiers in Plant Science, 2014Co-Authors: Alexandra Girondé, Philippe Etienne, Jacques Trouverie, Lucie Dubousset, Jean Christophe AviceAbstract:Our current knowledge about sulfur(S) management by winter oilseed rape to satisfy the S demand of developing seeds is still scarce, particularly in relation to S restriction. Our goals were to determine the physiological processes related to S use efficiency that led to maintain the seed yield and quality when S limitation occurred at the bolting or early flowering stages. To address these questions, a pulse-chase (SO42-)-S-34 labeling method was carried out in order to study the S fluxes from uptake and Remobilization at the whole plant level. In response of S limitation at the bolting or early flowering stages, the leaves are the most important source organ for S Remobilization during reproductive stages. By combining S-34-tracer with biochemical fractionation in order to separate sulfate from other S-compounds, it appeared that sulfate was the main form of S remobilized in leaves at reproductive stages and that tonoplastic SULTR4-type transporters were specifically involved in the sulfate remobilisation in case of low S availability. In response to S limitation at the bolting stage, the seed yield and quality were dramatically reduced compared to control plants. These data suggest that the increase of both S Remobilization from source leaves and the root proliferation in order to maximize sulfate uptake capacities, were not sufficient to maintain the seed yield and quality. When S limitation occurred at the early flowering stage, oilseed rape can optimize the mobilization of sulfate reserves from vegetative organs (leaves and stem) to satisfy the demand of seeds and maintain the seed yield and quality. Our study also revealed that the stem may act as a transient storage organ for remobilized S coming from source leaves before its utilization by seeds. The physiological traits (S Remobilization, root proliferation, transient S storage in stem) observed under S limitation could be used in breeding programs to select oilseed rape genotypes with high S use efficiency.
Iduna Arduini - One of the best experts on this subject based on the ideXlab platform.
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post anthesis dry matter and nitrogen dynamics in durum wheat as affected by nitrogen supply and soil water availability
European Journal of Agronomy, 2008Co-Authors: L Ercoli, Alessandro Masoni, Marco Mariotti, L Lulli, Iduna ArduiniAbstract:Abstract Durum wheat (Triticum durum Desf.) is commonly grown in dryland conditions, where environmental stress during grain filling can limit productivity and increase the dependency on stored assimilate. We investigated current assimilation and Remobilization of dry matter and nitrogen during grain filling in N fertilized and unfertilized durum wheat subjected to different levels of water deficit during grain filling. Two durum wheat varieties, Appio and Creso, were grown in open-air containers with three rates of nitrogen fertilizer (not applied, N0; normal amount, NN; high amount, NH) and four water regimes during grain filling (fully irrigated treatment, FI; low, LWS, moderate, MWS and high water stress, HWS) across 2 years. Grain yield and dry matter and N accumulation and Remobilization were positively affected by N availability and negatively by water stress during grain filling. The reduction of grain yield by severe post-anthesis water stress amounted to 27 and 37% for N0 and NN, respectively, and was associated with a decrease in kernel weight. There was also a small negative effect on the number of kernels per spike. Conversely, the duration of grain filling was not modified either by water stress or by nitrogen treatments. Severe water stress also reduced dry matter accumulation and Remobilization by 36 and 14% in N0 plants and by 48 and 25% in NH plants. Similarly, N accumulation and N Remobilization was reduced by 43% and by 16% in N0 plants and by 51% and by 15% in NH plants. Conversely, low and moderate water stress did not substantially modify the patterns of dry matter and nitrogen deposition in grain. Although Remobilization of dry matter and N was less affected by water stress than accumulation, it was not able to counterbalance the reduction of assimilation and consequently it was not able to stabilize grain yield under drought.
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post anthesis accumulation and Remobilization of dry matter nitrogen and phosphorus in durum wheat as affected by soil type
European Journal of Agronomy, 2007Co-Authors: Alessandro Masoni, L Ercoli, Marco Mariotti, Iduna ArduiniAbstract:The objective of the research was to quantify the changes in the accumulation of dry matter and N and P content of four durum wheat (Triticum durum Desf.) varieties grown on two soil types (sandy-loam and clay-loam), differing for texture, nitrogen content and water holding capacity. Plants were grown in containers and were rainfed until anthesis; irrigation was performed during grain filling to avoid water stress. The difference in total vegetative weight and nitrogen and phosphorus content of plants between anthesis and maturity was used to indirectly estimate the relative contribution of pre-anthesis assimilation and Remobilization to grain yield. The behaviour of the four varieties was similar as they ranked in the same order for pre-anthesis and post-anthesis dry matter accumulation and grain yield and differences in soil characteristics induced similar changes in dry matter, N and P accumulation and Remobilization. Soil type greatly affected the patterns of dry matter, N and P accumulation and Remobilization. Plants grown on clay-loam soil had higher dry weight and N and P content both at anthesis and at maturity and higher grain yield at maturity, compared to plants grown on sandy-loam soil and the Remobilization of dry matter, N and P were 75, 140 and 55% higher. Most of the grain carbohydrates originated from photosynthates produced during grain fill, as the contribution of Remobilization of dry matter to grain yield did not reach 30%, while most of the grain N and P originated from the Remobilization of N and P accumulated prior to anthesis as Remobilization of N accounted for 73–82% of grain N content and Remobilization of P accounted for 56–63% of grain P content.
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grain yield and dry matter and nitrogen accumulation and Remobilization in durum wheat as affected by variety and seeding rate
European Journal of Agronomy, 2006Co-Authors: Iduna Arduini, Alessandro Masoni, L Ercoli, Marco MariottiAbstract:Abstract The influence of crop density on the Remobilization of dry matter and nitrogen from vegetative plant parts to the developing grain, was investigated in the durum wheat ( Triticum durum Desf.) varieties Creso, Simeto and Svevo cultivated in the field at three seeding rates, 200, 250 and 400 seeds m −2 . Variety × seeding rate interaction was unsignificant for all recorded characters. Grain yield declined in the order Svevo > Simeto > Creso. Yield differences mainly depended on the different number of kernels per unit land and, secondly, on mean kernel weight. Spike components differed among varieties: Svevo and Simeto showed more kernels per spikelet and Creso more spikelets per spike. Grain yield was highest with 400 seeds m −2 primarily due to the higher number of spikes per unit area, and secondly, to the higher mean kernel weight. Post-heading dry matter accumulation was highest in Svevo and lowest in Creso, but varieties showed a reverse order for dry matter Remobilization and contribution of dry matter Remobilization to grain yield. The increase of seeding rate increased both the post-heading dry matter accumulation and the dry matter Remobilization from vegetative plant parts to grain. Nitrogen uptake of the whole crop and N content of grain was higher in Simeto and Svevo than in Creso. The N concentration of grain did not vary among varieties, but Svevo showed a markedly lower N concentration and N content of culms at maturity, which may be consequence of the high N Remobilization efficiency performed by this variety. The N uptake by the crop was highest with 400 seeds m −2 , but the N concentration of culms, leaves and even grain was slightly lower than with the lower seed rates. The post-heading N accumulation was by far higher in Simeto and Svevo than in Creso, whereas Remobilization was highest in Svevo and lowest in Simeto. The percentage contribution of N Remobilization to grain N was by far higher in Creso than in the other two varieties. Post-heading N accumulation and N Remobilization were highest with the highest plant density, but the contribution of N Remobilization to N grain content did not differ between seeding rates.
Philippe Etienne - One of the best experts on this subject based on the ideXlab platform.
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the contrasting n management of two oilseed rape genotypes reveals the mechanisms of proteolysis associated with leaf n Remobilization and the respective contributions of leaves and stems to n storage and Remobilization during seed filling
BMC Plant Biology, 2015Co-Authors: Alexandra Girondé, Philippe Etienne, Jacques Trouverie, Alain Bouchereau, Françoise Le Cahérec, Laurent Leport, Mathilde OrselAbstract:Oilseed rape is the third largest oleaginous crop in the world but requires high levels of N fertilizer of which only 50% is recovered in seeds. This weak N use efficiency is associated with a low foliar N Remobilization, leading to a significant return of N to the soil and a risk of pollution. Contrary to what is observed during senescence in the vegetative stages, N Remobilization from stems and leaves is considered efficient during monocarpic senescence. However, the contribution of stems towards N management and the cellular mechanisms involved in foliar Remobilization remain largely unknown. To reach this goal, the N fluxes at the whole plant level from bolting to mature seeds and the processes involved in leaf N Remobilization and proteolysis were investigated in two contrasting genotypes (Aviso and Oase) cultivated under ample or restricted nitrate supply. During seed filling in both N conditions, Oase efficiently allocated the N from uptake to seeds while Aviso favoured a better N Remobilization from stems and leaves towards seeds. Nitrate restriction decreased seed yield and oil quality for both genotypes but Aviso had the best seed N filling. Under N limitation, Aviso had a better N Remobilization from leaves to stems before the onset of seed filling. Afterwards, the higher N Remobilization from stems and leaves of Aviso led to a higher final N amount in seeds. This high leaf N Remobilization is associated with a better degradation/export of insoluble proteins, oligopeptides, nitrate and/or ammonia. By using an original method based on the determination of Rubisco degradation in the presence of inhibitors of proteases, efficient proteolysis associated with cysteine proteases and proteasome activities was identified as the mechanism of N Remobilization. The results confirm the importance of foliar N Remobilization after bolting to satisfy seed filling and highlight that an efficient proteolysis is mainly associated with (i) cysteine proteases and proteasome activities and (ii) a fine coordination between proteolysis and export mechanisms. In addition, the stem may act as transient storage organs in the case of an asynchronism between leaf N Remobilization and N demand for seed filling.
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The contrasting N management of two oilseed rape genotypes reveals the mechanisms of proteolysis associated with leaf N Remobilization and the respective contributions of leaves and stems to N storage and Remobilization during seed filling.
BMC Plant Biology, 2015Co-Authors: Alexandra Girondé, Philippe Etienne, Jacques Trouverie, Alain Bouchereau, Françoise Le Cahérec, Laurent Leport, Mathilde Orsel, Marie-françoise Niogret, Nathalie Nesi, Fabienne SoulayAbstract:Oilseed rape is the third largest oleaginous crop in the world but requires high levels of N fertilizer of which only 50% is recovered in seeds. This weak N use efficiency is associated with a low foliar N Remobilization, leading to a significant return of N to the soil and a risk of pollution. Contrary to what is observed during senescence in the vegetative stages, N Remobilization from stems and leaves is considered efficient during monocarpic senescence. However, the contribution of stems towards N management and the cellular mechanisms involved in foliar Remobilization remain largely unknown. To reach this goal, the N fluxes at the whole plant level from bolting to mature seeds and the processes involved in leaf N Remobilization and proteolysis were investigated in two contrasting genotypes (Aviso and Oase) cultivated under ample or restricted nitrate supply. Results: During seed filling in both N conditions, Oase efficiently allocated the N from uptake to seeds while Aviso favoured a better N Remobilization from stems and leaves towards seeds. Nitrate restriction decreased seed yield and oil quality for both genotypes but Aviso had the best seed N filling. Under N limitation, Aviso had a better N Remobilization from leaves to stems before the onset of seed filling. Afterwards, the higher N Remobilization from stems and leaves of Aviso led to a higher final N amount in seeds. This high leaf N Remobilization is associated with a better degradation/export of insoluble proteins, oligopeptides, nitrate and/or ammonia. By using an original method based on the determination of Rubisco degradation in the presence of inhibitors of proteases, efficient proteolysis associated with cysteine proteases and proteasome activities was identified as the mechanism of N Remobilization. Conclusion: The results confirm the importance of foliar N Remobilization after bolting to satisfy seed filling and highlight that an efficient proteolysis is mainly associated with (i) cysteine proteases and proteasome activities and (ii) a fine coordination between proteolysis and export mechanisms. In addition, the stem may act as transient storage organs in the case of an asynchronism between leaf N Remobilization and N demand for seed filling.
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A profiling approach of the natural variability of foliar N Remobilization at the rosette stage gives clues to understand the limiting processes involved in the low N use efficiency of winter oilseed rape
Journal of Experimental Botany, 2015Co-Authors: Alexandra Girondé, Philippe Etienne, Jacques Trouverie, Alain Bouchereau, Françoise Le Cahérec, Laurent Leport, Marie-françoise Niogret, Marine Poret, Mathilde Orsel Baldwin, Carole DeleuAbstract:Oilseed rape, a crop requiring a high level of nitogen (N) fertilizers, is characterized by low N use efficiency. To identify the limiting factors involved in the N use efficiency of winter oilseed rape, the response to low N supply was investigated at the vegetative stage in 10 genotypes by using long-term pulse-chase (15)N labelling and studying the physiological processes of leaf N Remobilization. Analysis of growth and components of N use efficiency allowed four profiles to be defined. Group 1 was characterized by an efficient N Remobilization under low and high N conditions but by a decrease of leaf growth under N limitation. Group 2 showed a decrease in leaf growth under low N supply that was associated with a low N Remobilization efficiency under both N supplies despite a high Remobilization of soluble proteins. In response to N limitation, Group 3 is characterized by an increase in N use efficiency and leaf N Remobilization compared with high N that is not sufficient to sustain the leaf biomass production at a similar level to non-limited plants. Genotypes of Group 4 subjected to low nitrate were able to maintain leaf growth to the same level as under high N. The profiling approach indicated that enhancement of amino acid export and soluble protein degradation was crucial for N Remobilization improvement. At the whole-plant level, N fluxes revealed that Group 4 showed a high N Remobilization in source leaves combined with a better N utilization in young leaves. Consequently, an enhanced N Remobilization limits N loss in fallen leaves, but this remobilized N needs to be efficiently utilized in young leaves to improve N use efficiency.
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The impact of sulfate restriction on seed yield and quality of winter oilseed rape depends on the ability to remobilize sulfate from vegetative tissues to reproductive organs
Frontiers in Plant Science, 2014Co-Authors: Alexandra Girondé, Philippe Etienne, Jacques Trouverie, Lucie Dubousset, Jean Christophe AviceAbstract:Our current knowledge about sulfur(S) management by winter oilseed rape to satisfy the S demand of developing seeds is still scarce, particularly in relation to S restriction. Our goals were to determine the physiological processes related to S use efficiency that led to maintain the seed yield and quality when S limitation occurred at the bolting or early flowering stages. To address these questions, a pulse-chase (SO42-)-S-34 labeling method was carried out in order to study the S fluxes from uptake and Remobilization at the whole plant level. In response of S limitation at the bolting or early flowering stages, the leaves are the most important source organ for S Remobilization during reproductive stages. By combining S-34-tracer with biochemical fractionation in order to separate sulfate from other S-compounds, it appeared that sulfate was the main form of S remobilized in leaves at reproductive stages and that tonoplastic SULTR4-type transporters were specifically involved in the sulfate remobilisation in case of low S availability. In response to S limitation at the bolting stage, the seed yield and quality were dramatically reduced compared to control plants. These data suggest that the increase of both S Remobilization from source leaves and the root proliferation in order to maximize sulfate uptake capacities, were not sufficient to maintain the seed yield and quality. When S limitation occurred at the early flowering stage, oilseed rape can optimize the mobilization of sulfate reserves from vegetative organs (leaves and stem) to satisfy the demand of seeds and maintain the seed yield and quality. Our study also revealed that the stem may act as a transient storage organ for remobilized S coming from source leaves before its utilization by seeds. The physiological traits (S Remobilization, root proliferation, transient S storage in stem) observed under S limitation could be used in breeding programs to select oilseed rape genotypes with high S use efficiency.
