Castor bean(Ricinus communis L.)is an economically important non-edible oilseed crop.Its seed oils are rich in hydroxy fatty acid,which are highly valuable with a wide range of industrial applications.Sucrose transpor...Castor bean(Ricinus communis L.)is an economically important non-edible oilseed crop.Its seed oils are rich in hydroxy fatty acid,which are highly valuable with a wide range of industrial applications.Sucrose transportation is critical in regulating the growth,development and oilseed yield in castor bean.The transporters or carriers(SUTs or SUCs)play a central role in orchestrating sucrose allocation and aiding in plant adaptation to diverse stresses.In this study,based on castor bean genome,three RcSUCs(RcSUC2,RcSUC3 and RcSUC4)were identified and characterized.The expressional profiles of RcSUCs in different tissues such as leaf,stem,root,phloem and seed tissues exhibited a distinct divergence of gene expression,suggesting that the functions of RcSUC2,RcSUC3 and RcSUC4 are differentiated into long or short-distance transportation among tissues.Additionally,under abiotic stresses including hot temperature,low temperature,drought and salt stresses,the sugar allocation among leaf,stem and roots was tested.The expressional changes of Rc SUCs in leaf,stem and root tissues were associated with sugar transportation and allocation.Taken together,the differential expression of Rc SUCs among tissues responsing to abiotic stress suggested functional differences in sucrose transport and redistribution in different tissues.This study is helpful to understand the physiological and molecular mechanisms of sucrose transportation and allocation among tissues in heterotrophic oilseeds,and could provide clues for genetic improvement and optimization of cultivation practices.展开更多
Herbivorous insects change the metabolism of the plant during their attack. Our study reports the changes in the expression pattern of sucrose transporters in response to the infestation of aphids at different time in...Herbivorous insects change the metabolism of the plant during their attack. Our study reports the changes in the expression pattern of sucrose transporters in response to the infestation of aphids at different time intervals. Results showed a significant enhancement in the expression pattern for six out of nine sucrose transporters in response to aphid infestation, followed by suppression after some point. During an earlier time point of infestation, the expressions of sucrose transporters were enhanced probably to compensate for the energy requirements of the damaged cell. However, suppression of sucrose transporters at a later stage may be a defense strategy of the plant to repel the aphids because at a later stage of infestation, aphids become a secondary sink. To complement our assumption, we performed aphid infestation choice and reproductive performance tests in the null mutant of one of the transporters, SUC2, which was compromised in phloem loading of sucrose. Results showed that the mutant was less preferable to aphid for choice as well as reproduction performance.展开更多
In higher plants, sugars （mainly sucrose） are produced by photosynthetically assimilated carbon in mesophyll cells of leaves and translocated to heterotrophic organs to ensure plant growth and devel- opment. Sucrose...In higher plants, sugars （mainly sucrose） are produced by photosynthetically assimilated carbon in mesophyll cells of leaves and translocated to heterotrophic organs to ensure plant growth and devel- opment. Sucrose transporters, or sucrose carriers （SUCs）, play an important role in the long-distance transportation of sucrose from source organs to sink organs, thereby affecting crop yield and quality. The identification, characterization, and molecular function analysis of sucrose transporter genes have been reported for monocot and dicot plants. However, no relevant study has been reported on sucrose transporter genes in Brassica rapa vat. rapa, a cruciferous root crop used mainly as vegetables and fodder. We identified and cloned 12 sucrose transporter genes from turnips, named BrrSUC1.1 to BrrSUCB.2 according to the SUC gene sequences of B. rapa pekinensis. We constructed a phylogenetic tree and analyzed conserved motifs for all 12 sucrose transporter genes identified. Real-time quantitative poly- merase chain reaction was conducted to understand the expression levels of SUC genes in different tissues and developmental phases of the turnip. These findings add to our understanding of the genetics and physiology of sugar transport during taproot formation in turnips.展开更多
An experiment was conducted to study the effects of sucrose supplementation, insulin injection, and resting period prior to slaughtering on meat quality in sheep exposed to stressful transportation. Fifty four local s...An experiment was conducted to study the effects of sucrose supplementation, insulin injection, and resting period prior to slaughtering on meat quality in sheep exposed to stressful transportation. Fifty four local sheep （10 to 12 months of age） with body weight （BW） ranged from 14 to 1 7 kg. The experimental sheep were assigned into a completely randomized design with a 2 × 3 × 3 factorial arrangement with 3 replications. The first factor was two levels of sucrose supplementation （0 and 6 g/kg BW）, the second factor was three levels of insulin injection after transportation （0, 0.3 and 0.6 IU/kg BW）, while the third factor was three duration time of resting period （2, 4 and 6 h prior to slaughtering）. Parameters measured were rectal temperature and heart rate, body weight, carcass percentage, meat pH, water holding capacity, meat tenderness, cooking loss and meat color. The results of the experiment showed that sheep after transportation had higher rectal temperature and heart rate, indicated that sheep supplemented with sucrose after transportation has a lower meat pH and cooking loss. The longer resting period prior to slaughtering has the lower body weight, but has higher carcass percentage. However, the treatments did not influence water holding capacity, meat tenderness and meat color. It was concluded that sucrose supplementation, insulin injection, and resting period prior to slaughtering in sheep exposed to stressful transportation could improve meat quality.展开更多
Soybean is a photoperiod-sensitive short-day crop whose reproductive period and yield are markedly affected by day-length changes.Seed weight is one of the key traits determining the soybean yield;how-ever,the promine...Soybean is a photoperiod-sensitive short-day crop whose reproductive period and yield are markedly affected by day-length changes.Seed weight is one of the key traits determining the soybean yield;how-ever,the prominent genes that control the final seed weight of soybean and the mechanisms underlying the photoperiod's effect on this trait remain poorly understood.In this study,we identify SwW19 as a major locus controlling soybean seed weight by QTL mapping and determine Dt1,an orthologous gene of Arabidopsis TFL1 that is known to govern the soybean growth habit,as the causal gene of the SW19 locus.We showed that Dt1 is highly expressed in developing seeds and regulates photoperiod-dependent seed weight in soybean.Further analyses revealed that the Dt1 protein physically interacts with the sucrose transporter GmSWEET10a to negatively regulate the import of sucrose from seed coat to the embryo,thus modulating seed weight under long days.However,Dt1 does not function in seed development under short days due to its very low expression.Importantly,we discovered a novel natural allelic variant of Dt1(H4 haplotype)that decouples its pleiotropic effects on seed size and growth habit;i.e.,this variant remains functional in seed development but fails to regulate the stem growth habit of soybean.Collectively,our findings provide new insights into how soybean seed development responds to photoperiod at different latitudes,offering an ideal genetic component for improving soybean's yield by manipulating its seed weightandgrowth habit.展开更多
In this work, the enzymatic hydrolysis reaction of sucrose through invertase under unsteady-state conditions has been investigated. The aim is to evaluate the inhibition phenomena influence on the reaction rate and, t...In this work, the enzymatic hydrolysis reaction of sucrose through invertase under unsteady-state conditions has been investigated. The aim is to evaluate the inhibition phenomena influence on the reaction rate and, then, on the concentration and temperature profiles by simulating the process in a tubular reactor, varying the enzyme concentration and the reactant mixture velocity. The transport phenomena considered during the enzymatic hydrolysis process have been described by means of unsteady-state momentum, mass and energy balance equations, taking into account molecular and convective transport and generation terms. Interpretation and discussion of the results obtained by FEM resolution of PDEs involved allow to understand the relevance of the operating parameters.展开更多
The majority of higher plants use sucrose as their main mobile carbohydrate. Proton-driven sucrose trans- porters play a crucial role in cell-to-cell and long-distance distribution of sucrose throughout the plant. A v...The majority of higher plants use sucrose as their main mobile carbohydrate. Proton-driven sucrose trans- porters play a crucial role in cell-to-cell and long-distance distribution of sucrose throughout the plant. A very negative plant membrane potential and the ability of sucrose transporters to accumulate sucrose concentrations of more than 1 M indicate that plants evolved transporters with unique structural and functional features. The knowledge about the trans- port mechanism and structural/functional domains of these the current knowledge about the biophysical properties of nano-machines is, however, still fragmentary. In this review, plant sucrose transporters is summarized and discussed.展开更多
Amino acids are important substances that must be transported to tissues such as the brain and muscles. The process is considered insulin dependent. It is not known whether all the amino acids are almost equally depen...Amino acids are important substances that must be transported to tissues such as the brain and muscles. The process is considered insulin dependent. It is not known whether all the amino acids are almost equally dependent in their transportation to tissues. We want to know whether some important amino acids are transported differently from other amino acids. Especially tryptophan is important because it is converted to serotonin, melatonin or kynurenine. Results showed that Amino acids levels in the plasma were measured after the intakes of 50 grams of glucose or sucrose to young (18 - 22 years old) and old (≥50 years old) men. Total amino acids in the plasma decreased after the intakes of glucose. Total amino acids levels decreased more significantly in old men after the administration of sucrose. Total and non-essential amino acids in the plasma decreased significantly at 120 min after the intakes of glucose in young and old men, but only sucrose caused their decreases in both aged and young men. Both glucose and sucrose intakes decreased significantly the plasma levels of the total essential and branched amino acids in young and old men. Surprisingly, plasma levels of tryptophan did not decrease upon the administration of glucose but only slightly decreased upon the administration of sucrose in young men. In conclusion, not all the amino acids were transported well into tissues upon the administration of glucose or sucrose. Tryptophan seems to be relatively resistant for insulin to facilitate the transportation into tissues.展开更多
In many plants, sucrose transporters are essential for both sucrose exports from sources and imports into sinks, indicating a function in assimilate partitioning. To investigate whether sucrose transporters can improv...In many plants, sucrose transporters are essential for both sucrose exports from sources and imports into sinks, indicating a function in assimilate partitioning. To investigate whether sucrose transporters can improve the yield of starch plant, potato plants （Solanum tuberosum L. cv. D^siree） were transformed with cDNAs of the rice sucrose transporter genes OsSUT5Z and OsSUT2M under the control of a tuber- specific, class-I patatin promoter. Compared to the controls, the average fructose content of OsSUTSZ transgenic tubers significantly increased. However, the content of the sugars and starch in the OsSUT2M transgenic potato tubers showed no obvious difference. Correspondingly, the average tuber yield, average number of tubers per plant and average weight of single tuber showed no significant difference in OsSUT2M transgenic tubers with controls. In the OsSUTSZ transgenic lines, the average tuber yield per plant was 1.9-fold higher than the controls, and the average number of tubers per plant increased by more than 10 tubers on average, whereas the average weight of a single tuber did not increase significantly. These results suggested that the average number of tubers per plant showed more contribution than the average weight of a single tuber to the tuber yield per plant.展开更多
We identified de novo sucrose transporter （SUT） genes involved in long-distance transport of sucrose from photosynthetic source leaves towards sink organs in the model leguminous species Medicago truncatula. The ide...We identified de novo sucrose transporter （SUT） genes involved in long-distance transport of sucrose from photosynthetic source leaves towards sink organs in the model leguminous species Medicago truncatula. The iden- tification and functional analysis of sugar transporters provide key information on mechanisms that underlie carbon partitioning in plant-microorganism interactions. In that way, full-length sequences of the M. truncatula SUT （MtSUT） family were retrieved and biochemical characterization of MtSUT members was performed by heterologous expression in yeast. The MtSUT family now comprises six genes which distribute among Dicotyledonous clades. MtSUTI-1 and MtSUT4-1 are key members in regard to their expression profiles in source leaves and sink roots and were characterized as functional H~/sucrose transporters. Physiological and molecular responses to phosphorus supply and inoculation by the arbuscular mycorrhizal fungus （AMF） Glomus intraradices was studied by gene expression and sugar quantification analyses. Sucrose represents the main sugar transport form in M. truncatula and the expression profiles of MtSUTI-1, MtSUT2, and MtSUT4-1 highlight a fine-tuning regulation for beneficial sugar fluxes towards the fungal symbiont. Taken together, these results suggest distinct functions for proteins from the SUT1, SUT2, and SUT4 clades in plant and in bio- trophic interactions.展开更多
It remains unknown whether a sucrose transporter mediates sugar signaling. Here, we report that the Arabidopsis （Arabidopsis thaliana） sucrose transporter SUT4 interacts with five members of the Arabidopsis cytochro...It remains unknown whether a sucrose transporter mediates sugar signaling. Here, we report that the Arabidopsis （Arabidopsis thaliana） sucrose transporter SUT4 interacts with five members of the Arabidopsis cytochrome b5 （Cyb5） family, and sucrose represses the interaction between SUT4 and a Cyb5 member Cyb5-2/A. We observed that down- regulation of SUT4 and three cytochrome b5 members （Cyb5-2, Cyb5-4, and Cyb5-6） confers the sucrose- and glucose- insensitive phenotypes in the sucrose/glucose-induced inhibition of seed germination. The sut4 cybS-2 double mutant displays slightly stronger sucrose/glucose-insensitive phenotypes than either the sut4 or cyb5-2 single mutant. We showed that the SUT4/Cyb5-2-mediated signaling in the sucrose/glucose-induced inhibition of seed germination does not require ABA or the currently known ABI2/ABI4/ABI5-mediated signaling pathway（s）. These data provide evidence that the sucrose transporter SUT4 interacts with Cyb5 to positively mediate sucrose and glucose signaling in the sucrose/ glucose-induced inhibition of seed germination.展开更多
Two sucrose transporter （SUT） cDNAs, OsSUT2M and OsSUT5Z, were isolated from rice （Oryza sativa L.） by reverse transcription polymerase chain reaction （RT-PCR）. Sequencing results indicate they are 1 531 bp and ...Two sucrose transporter （SUT） cDNAs, OsSUT2M and OsSUT5Z, were isolated from rice （Oryza sativa L.） by reverse transcription polymerase chain reaction （RT-PCR）. Sequencing results indicate they are 1 531 bp and 1 635 bp in length including complete open reading frame 1 506bp and 1 608 bp, which encode 502 amino acids and 536 amino acids, respectively. The TopPred program suggested that both sucrose transporter proteins, OsSUT2M and OsSUT5Z, consist of potentially 12 transmembrane domains. Semi-quantitative RT-PCR was carried out to investigate the gene expression patterns of OsSUT2M and OsSUT5Z. In vegetative organs, transcripts of OsSUT2M were higher in source leaf blades than in other organs at the same development stage, whereas transcripts of OsSUT5Z were less traceable in all organs investigated. In reproductive organs, both transcripts of these two genes were high in panicles from the booting stage to 7 days after flowering （DAF） and then sharply declined. The potential physiology functions of these two sucrose transporters are discussed.展开更多
Crop yield and quality are often limited by the amount of phosphate fertilizer added to infertile soils,a key limiting factor for sustainable development in modern agriculture.The polyphosphate kinase(ppk)gene-express...Crop yield and quality are often limited by the amount of phosphate fertilizer added to infertile soils,a key limiting factor for sustainable development in modern agriculture.The polyphosphate kinase(ppk)gene-expressing transgenic rice with a single-copy line(ETRS)is constructed to improve phosphate fertilizer utilization efficiency for phosphorus resource conservation.To investigate the potential mechanisms of the increased biomass in ETRS in low phosphate culture,ETRS was cultivated in a low inorganic phosphate(Pi)culture medium(15μmol/L Pi,LP)and a normal Pi culture medium(300μmol/L Pi,CP),respectively.After 89 d of cultivation in different concentrations of phosphate culture media,the total phosphorus,polyphosphate(polyP),biomass,photosynthetic rate,nonstructural carbohydrate(NSC)contents,related enzyme activities,and related gene expression levels were analyzed.The results showed that ETRS had a high polyP amount to promote the photosynthetic rate in LP,and its biomass was almost the same as the wild type(WT)in CP.The NSC content of ETRS in LP was higher than that of WT in LP,but slightly lower than that of WT in CP.PolyP notably promoted the sucrose phosphate synthase activities of ETRS and significantly down-regulated the expression levels of sucrose transporter genes(OsSUT3 and OsSUT4),resulting in inhibiting the transport of sucrose from shoot to root in ETRS.It was concluded that polyP can stimulate the synthesis of NSCs in LP,which improved the growth of ETRS and triggered the biological activities of ETRS to save phosphate fertilizer.Our study provides a new way to improve the utilization rate of phosphate fertilizer in rice production.展开更多
基金supported by the National Natural Science Foundation of China(31661143002 and 31771839)。
文摘Castor bean(Ricinus communis L.)is an economically important non-edible oilseed crop.Its seed oils are rich in hydroxy fatty acid,which are highly valuable with a wide range of industrial applications.Sucrose transportation is critical in regulating the growth,development and oilseed yield in castor bean.The transporters or carriers(SUTs or SUCs)play a central role in orchestrating sucrose allocation and aiding in plant adaptation to diverse stresses.In this study,based on castor bean genome,three RcSUCs(RcSUC2,RcSUC3 and RcSUC4)were identified and characterized.The expressional profiles of RcSUCs in different tissues such as leaf,stem,root,phloem and seed tissues exhibited a distinct divergence of gene expression,suggesting that the functions of RcSUC2,RcSUC3 and RcSUC4 are differentiated into long or short-distance transportation among tissues.Additionally,under abiotic stresses including hot temperature,low temperature,drought and salt stresses,the sugar allocation among leaf,stem and roots was tested.The expressional changes of Rc SUCs in leaf,stem and root tissues were associated with sugar transportation and allocation.Taken together,the differential expression of Rc SUCs among tissues responsing to abiotic stress suggested functional differences in sucrose transport and redistribution in different tissues.This study is helpful to understand the physiological and molecular mechanisms of sucrose transportation and allocation among tissues in heterotrophic oilseeds,and could provide clues for genetic improvement and optimization of cultivation practices.
文摘Herbivorous insects change the metabolism of the plant during their attack. Our study reports the changes in the expression pattern of sucrose transporters in response to the infestation of aphids at different time intervals. Results showed a significant enhancement in the expression pattern for six out of nine sucrose transporters in response to aphid infestation, followed by suppression after some point. During an earlier time point of infestation, the expressions of sucrose transporters were enhanced probably to compensate for the energy requirements of the damaged cell. However, suppression of sucrose transporters at a later stage may be a defense strategy of the plant to repel the aphids because at a later stage of infestation, aphids become a secondary sink. To complement our assumption, we performed aphid infestation choice and reproductive performance tests in the null mutant of one of the transporters, SUC2, which was compromised in phloem loading of sucrose. Results showed that the mutant was less preferable to aphid for choice as well as reproduction performance.
基金supported by Major Program of National Natural Science Foundation of China (31590820,31590823)
文摘In higher plants, sugars （mainly sucrose） are produced by photosynthetically assimilated carbon in mesophyll cells of leaves and translocated to heterotrophic organs to ensure plant growth and devel- opment. Sucrose transporters, or sucrose carriers （SUCs）, play an important role in the long-distance transportation of sucrose from source organs to sink organs, thereby affecting crop yield and quality. The identification, characterization, and molecular function analysis of sucrose transporter genes have been reported for monocot and dicot plants. However, no relevant study has been reported on sucrose transporter genes in Brassica rapa vat. rapa, a cruciferous root crop used mainly as vegetables and fodder. We identified and cloned 12 sucrose transporter genes from turnips, named BrrSUC1.1 to BrrSUCB.2 according to the SUC gene sequences of B. rapa pekinensis. We constructed a phylogenetic tree and analyzed conserved motifs for all 12 sucrose transporter genes identified. Real-time quantitative poly- merase chain reaction was conducted to understand the expression levels of SUC genes in different tissues and developmental phases of the turnip. These findings add to our understanding of the genetics and physiology of sugar transport during taproot formation in turnips.
文摘An experiment was conducted to study the effects of sucrose supplementation, insulin injection, and resting period prior to slaughtering on meat quality in sheep exposed to stressful transportation. Fifty four local sheep （10 to 12 months of age） with body weight （BW） ranged from 14 to 1 7 kg. The experimental sheep were assigned into a completely randomized design with a 2 × 3 × 3 factorial arrangement with 3 replications. The first factor was two levels of sucrose supplementation （0 and 6 g/kg BW）, the second factor was three levels of insulin injection after transportation （0, 0.3 and 0.6 IU/kg BW）, while the third factor was three duration time of resting period （2, 4 and 6 h prior to slaughtering）. Parameters measured were rectal temperature and heart rate, body weight, carcass percentage, meat pH, water holding capacity, meat tenderness, cooking loss and meat color. The results of the experiment showed that sheep after transportation had higher rectal temperature and heart rate, indicated that sheep supplemented with sucrose after transportation has a lower meat pH and cooking loss. The longer resting period prior to slaughtering has the lower body weight, but has higher carcass percentage. However, the treatments did not influence water holding capacity, meat tenderness and meat color. It was concluded that sucrose supplementation, insulin injection, and resting period prior to slaughtering in sheep exposed to stressful transportation could improve meat quality.
基金supported by the National Natural Science Foundation of China(grant no.32090064 to F.K.)the National Key R&D Program of China(2021YFF1001203 to X.H.)+3 种基金the“Strategic Priority Research Program"of the Chinese Academy of Sciences(grant no.XDA24010105 to X.H.)the National Natural Science Foundation of China(grant nos.32230078 and 31871643 to X.H.)the Major Program of Guangdong Basic and Applied Research(grant no.2019B030302006 to F.K.)the Guangzhou Municipal Science and Technology Project(grant no.202201010641toY.H.).
文摘Soybean is a photoperiod-sensitive short-day crop whose reproductive period and yield are markedly affected by day-length changes.Seed weight is one of the key traits determining the soybean yield;how-ever,the prominent genes that control the final seed weight of soybean and the mechanisms underlying the photoperiod's effect on this trait remain poorly understood.In this study,we identify SwW19 as a major locus controlling soybean seed weight by QTL mapping and determine Dt1,an orthologous gene of Arabidopsis TFL1 that is known to govern the soybean growth habit,as the causal gene of the SW19 locus.We showed that Dt1 is highly expressed in developing seeds and regulates photoperiod-dependent seed weight in soybean.Further analyses revealed that the Dt1 protein physically interacts with the sucrose transporter GmSWEET10a to negatively regulate the import of sucrose from seed coat to the embryo,thus modulating seed weight under long days.However,Dt1 does not function in seed development under short days due to its very low expression.Importantly,we discovered a novel natural allelic variant of Dt1(H4 haplotype)that decouples its pleiotropic effects on seed size and growth habit;i.e.,this variant remains functional in seed development but fails to regulate the stem growth habit of soybean.Collectively,our findings provide new insights into how soybean seed development responds to photoperiod at different latitudes,offering an ideal genetic component for improving soybean's yield by manipulating its seed weightandgrowth habit.
文摘In this work, the enzymatic hydrolysis reaction of sucrose through invertase under unsteady-state conditions has been investigated. The aim is to evaluate the inhibition phenomena influence on the reaction rate and, then, on the concentration and temperature profiles by simulating the process in a tubular reactor, varying the enzyme concentration and the reactant mixture velocity. The transport phenomena considered during the enzymatic hydrolysis process have been described by means of unsteady-state momentum, mass and energy balance equations, taking into account molecular and convective transport and generation terms. Interpretation and discussion of the results obtained by FEM resolution of PDEs involved allow to understand the relevance of the operating parameters.
文摘The majority of higher plants use sucrose as their main mobile carbohydrate. Proton-driven sucrose trans- porters play a crucial role in cell-to-cell and long-distance distribution of sucrose throughout the plant. A very negative plant membrane potential and the ability of sucrose transporters to accumulate sucrose concentrations of more than 1 M indicate that plants evolved transporters with unique structural and functional features. The knowledge about the trans- port mechanism and structural/functional domains of these the current knowledge about the biophysical properties of nano-machines is, however, still fragmentary. In this review, plant sucrose transporters is summarized and discussed.
文摘Amino acids are important substances that must be transported to tissues such as the brain and muscles. The process is considered insulin dependent. It is not known whether all the amino acids are almost equally dependent in their transportation to tissues. We want to know whether some important amino acids are transported differently from other amino acids. Especially tryptophan is important because it is converted to serotonin, melatonin or kynurenine. Results showed that Amino acids levels in the plasma were measured after the intakes of 50 grams of glucose or sucrose to young (18 - 22 years old) and old (≥50 years old) men. Total amino acids in the plasma decreased after the intakes of glucose. Total amino acids levels decreased more significantly in old men after the administration of sucrose. Total and non-essential amino acids in the plasma decreased significantly at 120 min after the intakes of glucose in young and old men, but only sucrose caused their decreases in both aged and young men. Both glucose and sucrose intakes decreased significantly the plasma levels of the total essential and branched amino acids in young and old men. Surprisingly, plasma levels of tryptophan did not decrease upon the administration of glucose but only slightly decreased upon the administration of sucrose in young men. In conclusion, not all the amino acids were transported well into tissues upon the administration of glucose or sucrose. Tryptophan seems to be relatively resistant for insulin to facilitate the transportation into tissues.
基金supported by the State Key Basic Research and Development Plan of China,the Innovation Foundation of the Chinese Academy of Science,the Program Strategic Scientific Alliances and the China Exchange Program between China and The Netherlands
文摘In many plants, sucrose transporters are essential for both sucrose exports from sources and imports into sinks, indicating a function in assimilate partitioning. To investigate whether sucrose transporters can improve the yield of starch plant, potato plants （Solanum tuberosum L. cv. D^siree） were transformed with cDNAs of the rice sucrose transporter genes OsSUT5Z and OsSUT2M under the control of a tuber- specific, class-I patatin promoter. Compared to the controls, the average fructose content of OsSUTSZ transgenic tubers significantly increased. However, the content of the sugars and starch in the OsSUT2M transgenic potato tubers showed no obvious difference. Correspondingly, the average tuber yield, average number of tubers per plant and average weight of single tuber showed no significant difference in OsSUT2M transgenic tubers with controls. In the OsSUTSZ transgenic lines, the average tuber yield per plant was 1.9-fold higher than the controls, and the average number of tubers per plant increased by more than 10 tubers on average, whereas the average weight of a single tuber did not increase significantly. These results suggested that the average number of tubers per plant showed more contribution than the average weight of a single tuber to the tuber yield per plant.
文摘We identified de novo sucrose transporter （SUT） genes involved in long-distance transport of sucrose from photosynthetic source leaves towards sink organs in the model leguminous species Medicago truncatula. The iden- tification and functional analysis of sugar transporters provide key information on mechanisms that underlie carbon partitioning in plant-microorganism interactions. In that way, full-length sequences of the M. truncatula SUT （MtSUT） family were retrieved and biochemical characterization of MtSUT members was performed by heterologous expression in yeast. The MtSUT family now comprises six genes which distribute among Dicotyledonous clades. MtSUTI-1 and MtSUT4-1 are key members in regard to their expression profiles in source leaves and sink roots and were characterized as functional H~/sucrose transporters. Physiological and molecular responses to phosphorus supply and inoculation by the arbuscular mycorrhizal fungus （AMF） Glomus intraradices was studied by gene expression and sugar quantification analyses. Sucrose represents the main sugar transport form in M. truncatula and the expression profiles of MtSUTI-1, MtSUT2, and MtSUT4-1 highlight a fine-tuning regulation for beneficial sugar fluxes towards the fungal symbiont. Taken together, these results suggest distinct functions for proteins from the SUT1, SUT2, and SUT4 clades in plant and in bio- trophic interactions.
基金This research was supported by the National Natural Science Foundation of China
文摘It remains unknown whether a sucrose transporter mediates sugar signaling. Here, we report that the Arabidopsis （Arabidopsis thaliana） sucrose transporter SUT4 interacts with five members of the Arabidopsis cytochrome b5 （Cyb5） family, and sucrose represses the interaction between SUT4 and a Cyb5 member Cyb5-2/A. We observed that down- regulation of SUT4 and three cytochrome b5 members （Cyb5-2, Cyb5-4, and Cyb5-6） confers the sucrose- and glucose- insensitive phenotypes in the sucrose/glucose-induced inhibition of seed germination. The sut4 cybS-2 double mutant displays slightly stronger sucrose/glucose-insensitive phenotypes than either the sut4 or cyb5-2 single mutant. We showed that the SUT4/Cyb5-2-mediated signaling in the sucrose/glucose-induced inhibition of seed germination does not require ABA or the currently known ABI2/ABI4/ABI5-mediated signaling pathway（s）. These data provide evidence that the sucrose transporter SUT4 interacts with Cyb5 to positively mediate sucrose and glucose signaling in the sucrose/ glucose-induced inhibition of seed germination.
基金Supported by the State Key Basic Research and Development Plan of China (2004CB720406)Innovation Foundation of the Chinese Academy of Sciences (KSCXZ-SW-306 and KSCX-SW-03)+1 种基金Program Strategic Scientific Alliances (KNAW-PSA, 04-PSA-BD-04 for P.B.F.O.)the China Exchange Program (KNAW-CEP, 04CDp022 for Y.X.) between China and The Netherlands.
文摘Two sucrose transporter （SUT） cDNAs, OsSUT2M and OsSUT5Z, were isolated from rice （Oryza sativa L.） by reverse transcription polymerase chain reaction （RT-PCR）. Sequencing results indicate they are 1 531 bp and 1 635 bp in length including complete open reading frame 1 506bp and 1 608 bp, which encode 502 amino acids and 536 amino acids, respectively. The TopPred program suggested that both sucrose transporter proteins, OsSUT2M and OsSUT5Z, consist of potentially 12 transmembrane domains. Semi-quantitative RT-PCR was carried out to investigate the gene expression patterns of OsSUT2M and OsSUT5Z. In vegetative organs, transcripts of OsSUT2M were higher in source leaf blades than in other organs at the same development stage, whereas transcripts of OsSUT5Z were less traceable in all organs investigated. In reproductive organs, both transcripts of these two genes were high in panicles from the booting stage to 7 days after flowering （DAF） and then sharply declined. The potential physiology functions of these two sucrose transporters are discussed.
文摘夜间补光已成为设施蔬菜生产的重要手段,但多采用强光,耗能大、成本高,而夜间弱光补光对蔬菜生产的影响尚不清楚。为探讨夜间弱光补光对番茄生长和源库间蔗糖转运的影响,以Micro Tom番茄为材料,从植株4叶1心时期到果实绿熟期,以不补光为对照(CK),每天关灯1 h后进行4 h 15(SL15)和30μmol·m^(-2)·s^(-1)(SL30)低于光补偿点的两种补光处理。结果表明,与CK相比,SL15和SL30两个处理均显著提高番茄株高、茎粗和鲜质量;补光明显改善了根系形态,显著增加了总根长、总表面积和根尖数;补光促进开花,表现为开花株数和总开花数显著高于CK。以上生理指标SL15和SL30两个处理之间没有显著差异。与CK相比,SL15处理显著降低了成熟叶片和茎(源)的蔗糖含量,提高了果实和根系(库)的蔗糖含量,促进了蔗糖转运基因SUT1、SUT4、SWEET10b、SWEET11b和SWEET14在叶片、茎、果实和根系不同程度地上调表达,但叶片、茎、果实和根系4个器官总体的蔗糖含量没有显著差异。此外,SL15处理显著提高了叶片、茎、果实和根系4个器官中与蔗糖转运相关激素脱落酸的含量及其合成和信号标志基因NCED1、AAO3和ABI5的表达量。综上所述,夜间弱光补光可促进番茄生长及源库间蔗糖转运,研究结果为推广夜间弱光补光、降低补光成本、促进设施蔬菜高效绿色发展提供了新思路。
基金supported by the National Natural Science Foundation of China(Grant No.41871082)the Scientific Research Project of Ecological Environment Department of Jiangsu Province,China(Grant Nos.2020019 and 2021005)the National Special Program of Water Environment,China(Grant No.2017ZX07204002).
文摘Crop yield and quality are often limited by the amount of phosphate fertilizer added to infertile soils,a key limiting factor for sustainable development in modern agriculture.The polyphosphate kinase(ppk)gene-expressing transgenic rice with a single-copy line(ETRS)is constructed to improve phosphate fertilizer utilization efficiency for phosphorus resource conservation.To investigate the potential mechanisms of the increased biomass in ETRS in low phosphate culture,ETRS was cultivated in a low inorganic phosphate(Pi)culture medium(15μmol/L Pi,LP)and a normal Pi culture medium(300μmol/L Pi,CP),respectively.After 89 d of cultivation in different concentrations of phosphate culture media,the total phosphorus,polyphosphate(polyP),biomass,photosynthetic rate,nonstructural carbohydrate(NSC)contents,related enzyme activities,and related gene expression levels were analyzed.The results showed that ETRS had a high polyP amount to promote the photosynthetic rate in LP,and its biomass was almost the same as the wild type(WT)in CP.The NSC content of ETRS in LP was higher than that of WT in LP,but slightly lower than that of WT in CP.PolyP notably promoted the sucrose phosphate synthase activities of ETRS and significantly down-regulated the expression levels of sucrose transporter genes(OsSUT3 and OsSUT4),resulting in inhibiting the transport of sucrose from shoot to root in ETRS.It was concluded that polyP can stimulate the synthesis of NSCs in LP,which improved the growth of ETRS and triggered the biological activities of ETRS to save phosphate fertilizer.Our study provides a new way to improve the utilization rate of phosphate fertilizer in rice production.
