Under NaCl stress for 2 d, H+-ATPase activity increased, and H+-PPase activity decreased in the tonoplast of salt-tolerant barley ( Hordeum vulgare L. cv. 'Tanyin 2') roots. La3+ (1 mmol/L), an inhibitor of Ca...Under NaCl stress for 2 d, H+-ATPase activity increased, and H+-PPase activity decreased in the tonoplast of salt-tolerant barley ( Hordeum vulgare L. cv. 'Tanyin 2') roots. La3+ (1 mmol/L), an inhibitor of Ca2+ channel in plasma membrane, and EGTA (5 mmol/L), a Ca2+ chelator, inhibited this NaCl-induced increase in H+-ATPase activity but stimulated the H+-PPase activity. Treatment of barley roots with CaM antagonist (trifluoperazine, TFP, 20 mumol/L) also diminished the increase of H+-ATPase activity induced by NaCl. La3+, TFP or La3+ + TFP increased Na+ uptake and decreased K+ and Ca2+ uptake in barley roots under NaCl stress. These results suggested that the activation of tonoplast H+-ATPase and the regulation of Na+ and K+ uptake under NaCl stress may be related to Ca2+-CaM system.展开更多
Effect of nitrate and ammonium on the activity of tonoplast pyrophosphatase (V-PPase) was investigated in the roots of tomato ( Lycopersicon esculentum L.). The results showed that the activity of V-PPase was increase...Effect of nitrate and ammonium on the activity of tonoplast pyrophosphatase (V-PPase) was investigated in the roots of tomato ( Lycopersicon esculentum L.). The results showed that the activity of V-PPase was increased by ammonium nutrition, compared with nitrate nutrition. The H+ transport of tonoplast vesicles by V-PPase was also stimulated by ammonium nutrition. The result of Western blot indicated that the protein amount of V-PPase was increased by ammonium nutrition.展开更多
To study the function and adaptive mechanism of tonoplast H + ATPase under salt stress, pea ( Pisum sativum L.) seedlings were treated with different concentrations of salt (100-250 mmol/L NaCl) and with 100 mmol...To study the function and adaptive mechanism of tonoplast H + ATPase under salt stress, pea ( Pisum sativum L.) seedlings were treated with different concentrations of salt (100-250 mmol/L NaCl) and with 100 mmol/L NaCl for different days (1-3 d). The ATP hydrolytic activity and the proton transport activity and the changes of the amount of tonoplast H + ATPase (subunit A) were measured. ATP hydrolytic activity of H + ATPase prepared from plants treated with 250 mmol/L NaCl was reduced by about 25% compared to that of control plants, but that of stressed plants treated with 100 mmol/L and 200 mmol/L NaCl was unchanged. The activity from plants treated with 100 mmol/L NaCl for up to 3 d was lower than that of control plants by 20%. But the proton transport activity was increased under the same salt stresses as above. These results showed that the changes of the hydrolytic activity and the proton transport activity were not in proportion and salt stress may cause the change of the coupling ratio of H + transport activity to ATP hydrolysis. The protein amount kept unchanged and reduced a little only when pea was treated with 100 mmol/L NaCl for 3 d. These results indicated that salinity stimulated the increase of the pump efficiency of the V_ATPase from pea roots, which was due to the change of the coupling ratio, but not due to the increase of ATP hydrolysis and the amount of V_ATPase.展开更多
For understanding the function of tonoplast protein in plant cell signal pathway, we have identified an integral protein kinase activity from the highly purified tonoplast isolated from maize ( Zea mays L.) root by...For understanding the function of tonoplast protein in plant cell signal pathway, we have identified an integral protein kinase activity from the highly purified tonoplast isolated from maize ( Zea mays L.) root by a new nonradioactive method in which a color labeled peptide was used as substrate. The protein kinase was Ca 2+ _dependent and CaM and phosphatidylserine_independent, like the calmodulin_like domain protein kinase (CDPK) in many plants. The optimal pH value and Ca 2+ concentration were 6.5 and 10 μmol/L, respectively. According to the optimal pH value and the effect of detergent, it could be inferred that the active site of this protein kinase is oriented toward the cytoplasm. Zn 2+ had no obvious effect on its activity, indicating that this protein kinase has no zinc_finger domain that exists in some mammalian protein kinases. At the same time, when tonoplast proteins were prephosphorylated in the presence of Ca 2+ and ATP, both the ATP_hydrolysis and the proton_transport activity of vacuolar H +_ATPase were stimulated. This stimulation could be reversed by an alkaline_phosphatase. These results indicate that a Ca 2+ _dependent protein kinase was located in the tonoplast, and a Ca 2+ _dependent phosphorylation, probably caused by this kinase, activated the vacuolar H +_ATPase activity. These results are helpful for further research on the function of CDPK in the course of signal transduction in plants.展开更多
The effects of NaCl stress on the H +-ATPase, H +-PPase activity and lipid composition of plasma membrane(PM) and tonoplast(TP) vesicles isolated from roots and leaves of two soybean cultivars(Glycine max L.) differ...The effects of NaCl stress on the H +-ATPase, H +-PPase activity and lipid composition of plasma membrane(PM) and tonoplast(TP) vesicles isolated from roots and leaves of two soybean cultivars(Glycine max L.) differing in salt tolerance(Wenfeng7, salt-tolerant; Union, salt-sensitive) were investigated. When Wenfeng7 was treated with 0.3%(W/V) NaCl for 3 d, the H +-ATPase activities in PM and TP from roots and leaves exhibited a reduction and an enhancement, respectively. The H +-PPase activity in TP from roots also increased. Similar effects were not observed in roots of Union. In addition, the increases of phospholipid content and ratios of phospholipid to galactolipid in PM and TP from roots and leaves of Wenfeng7 may also change membrane permeability and hence affect salt tolerance.展开更多
Fruit taste quality is greatly influenced by the content of soluble sugars,which are predominantly stored in the vacuolar lumen.However,the accumulation and regulation mechanisms of sugars in most fruits remain unclea...Fruit taste quality is greatly influenced by the content of soluble sugars,which are predominantly stored in the vacuolar lumen.However,the accumulation and regulation mechanisms of sugars in most fruits remain unclear.Recently,we established the citrus fruit vacuole proteome and discovered the major transporters localized in the vacuole membrane.Here,we demonstrated that the expression of tonoplast sugar transporter 2(CsTST2)is closely associated with sugar accumulation during sweet orange(Citrus sinensis)ripening.It was further demonstrated that CsTST2 had the function of transporting hexose and sucrose into the vacuole.Overexpression of CsTST2 resulted in an elevation of sugar content in citrus juice sac,calli,and tomato fruit,whereas the downregulation of its expression led to the reduction in sugar levels.CsTST2 was identified as interacting with CsCIPK23,which binds to the upstream calcium signal sensor protein CsCBL1.The phosphorylation of the three serine residues(Ser277,Ser337,and Ser354)in the loop region of CsTST2 by CsCIPK23 is crucial for maintaining the sugar transport activity of CsTST2.Additionally,the expression of CsCIPK23 is positively correlated with sugar content.Genetic evidence further confirmed that calcium and CsCIPK23-mediated increase in sugar accumulation depends on CsTST2 and its phosphorylation level.These findings not only unveil the functional mechanism of CsTST2 in sugar accumulation,but also explore a vital calcium signal regulation module of CsCBL1/CIPK23 for citrus sweetness quality.展开更多
Fruit yield and quality are antagonistically regulated traits in tomato.An excessive focus on increasing yield often leads to a decline in quality.Achieving a delicate balance between high yield and desirable fruit qu...Fruit yield and quality are antagonistically regulated traits in tomato.An excessive focus on increasing yield often leads to a decline in quality.Achieving a delicate balance between high yield and desirable fruit quality is a challenging aspect of tomato breeding.In this study,we discovered that disrupting the function of the tomato tonoplast sugar transporter 3a(TST3a)significantly enhances both fruit weight andflavor.Three TSTs have been identified in tomato,namely SlTST1,SlTST3a,and SlTST3b;they possess the same sugar transport specificity for fructose and glucose and redundantly control cell expansion during fruit develop-ment.Sugar accumulation in sltst mutants correlates significantly with fruit size andflavor.The enlarged fruits in sltst3a mutants result from sugar accumulation due to the increased abundance of SlTST1 at the tonoplast coupled with the highest sugar transport capacity of SlTST1 among the three SlTSTs.Further ex-periments established that SlTST3a prevents the localization of SlTST1 to the tonoplast by inhibiting its interaction with VH1-interacting kinase(SlVIK).Mutation of SlTST3a in cultivated tomato can enhance both tomato fruit size and sugar content.Ourfindings offer potential avenues for simultaneously improving fruit quality and yield,providing valuable insights into the mechanisms underlying sugar storage during fruit development.展开更多
We have mapped the expression of the tonoplast intrinsic protein （TIP） gene family members in Arabidopsis seeds by fluorescent protein tagging of their genomic sequences and confocal microscopy. Three isoforms （TIP...We have mapped the expression of the tonoplast intrinsic protein （TIP） gene family members in Arabidopsis seeds by fluorescent protein tagging of their genomic sequences and confocal microscopy. Three isoforms （TIP1;1, TIP2;1, and TIP2;2） have distinct patterns of expression in maternal tissues （outer integument and placento-chalazal region）. Two isoforms, TIP3;1 and the previously uncharacterized TIP3;2, are the only detectable TIPs in embryos during seed maturation and the early stages of seed germination. Throughout these developmental stages, both isoforms co-locate to the tono- plast of the protein storage vacuoles, but also appear to label the plasma membrane. Plasma membrane labeling is specific to TIP3;1 and TIP3;2, is independent of the position of the fluorescent protein tag, and appears to be specific to early seed maturation and early germination stages. We discuss these results in the context of the predicted distribution of aquaporins in Arabidopsis seeds.展开更多
Both enhanced were H^+ transport activities of tonoplast vesicles isolated from roots of the salt-tolerant mutant and wild type of wheat with treatment of NaCI, but the activity of the mutant was significantly higher ...Both enhanced were H^+ transport activities of tonoplast vesicles isolated from roots of the salt-tolerant mutant and wild type of wheat with treatment of NaCI, but the activity of the mutant was significantly higher than that of wild type. H^+ transport activity was indicated as the stable value of fluorescence quenching per mg membrane proteins. The H^+ transport activities dependent on ATP of the mutant and wild type were 1099 and 558 respectively and their activities dependent on PPi were 358 and 228 separately.展开更多
Summary Vacuolar trafficking routes and their regu- lators have recently drawn lots of attention in plant cell biology. A recent study reported the discovery of a plant-specific vacuolar trafficking route, i.e., a dir...Summary Vacuolar trafficking routes and their regu- lators have recently drawn lots of attention in plant cell biology. A recent study reported the discovery of a plant-specific vacuolar trafficking route, i.e., a direct ER- to-vacuole route, through analysis of VHA-a3 subcellular targeting, a key component for the tonoplast V- ATPases. Our recent findings showed that VHA-a3 targets to the tonoplast through a Rab5-mediated but Rab7-independent pathway, shedding new lights on the unconventional vacuolar trafficking route in plant cells.展开更多
Subject Code:C02With the support by the National Natural Science Foundation of China,the research team led by Prof.Lin Jinxing(林金星)at the College of Biological Sciences&Biotechnology,Beijing Forestry University...Subject Code:C02With the support by the National Natural Science Foundation of China,the research team led by Prof.Lin Jinxing(林金星)at the College of Biological Sciences&Biotechnology,Beijing Forestry University,overcame the limitations of existing techniques and expanded the study of protein characteristics from the plasma membrane to the vacuole membranes.This study was published in Molecular Plant(2016,DOI:展开更多
Aquaporins are implicated in a wide variety of plant physiological processes, although the mechanisms involved in their regulation are not fully understood. To gain further insight into the regulatory factors involved...Aquaporins are implicated in a wide variety of plant physiological processes, although the mechanisms involved in their regulation are not fully understood. To gain further insight into the regulatory factors involved in this process, we used a yeast two-hybrid system to screen for potential binding partners to the Arabidopsis tonoplast intrinsic protein (TIP) AtTIP1;1. This was the first protein identified to be associated with high water permeability in vacuolar membranes from Arabidopsis thaliana. Using AtTIP1;1 as bait, a novel binding protein was identified in both yeast and plant cells. This prey protein, named AtSM34, was a 309 aa polypeptide with a predicted molecular mass of 34 kD and contained a single MYB/SANT-like domain. AtSM34 promoter:: GUS histochemical staining analysis detected AtSM34 expression in flowers, stems and leaves, particularly in the vascular tissues, in response to osmotic stress. AtSM34 expression was localized in the endoplasmic reticulum membrane, and sequence deletion analysis revealed that the N-terminal coding region (amino acids 1-83) was critical for this localization. Overexpression of AtSM34 resulted in hypersensitivity to exogenous mannitol, sorbitol and abscisic acid, and caused a significant delay in germination. AtSM34 interacted with AtTIP1;2 and AtTIP2;1, which are essential proteins for modulation of tonoplast permeability and highly expressed in germinating seedlings. These data indicate AtSM34 is a novel TIPs binding protein involved in the osmotic stress response of seedlings at an early stage of development.展开更多
The growth of barley (Hordeum vulgare L.) seedling is inhibited by 300 mmol/L NaCl. When 20 mg/L GSH is present in the hydroponic culture solution with NaCl, root length, root and shoot dry weigh, chlorophyll as well ...The growth of barley (Hordeum vulgare L.) seedling is inhibited by 300 mmol/L NaCl. When 20 mg/L GSH is present in the hydroponic culture solution with NaCl, root length, root and shoot dry weigh, chlorophyll as well as K+ contents are increased, Na+ content is decreased. At the same time the activities of H+-ATPase and H+-PPase associated with tonoplast vesicles isolated from leaves are stimulated, and electrolytic leakage are diminished by exogenous GSH.展开更多
文摘Under NaCl stress for 2 d, H+-ATPase activity increased, and H+-PPase activity decreased in the tonoplast of salt-tolerant barley ( Hordeum vulgare L. cv. 'Tanyin 2') roots. La3+ (1 mmol/L), an inhibitor of Ca2+ channel in plasma membrane, and EGTA (5 mmol/L), a Ca2+ chelator, inhibited this NaCl-induced increase in H+-ATPase activity but stimulated the H+-PPase activity. Treatment of barley roots with CaM antagonist (trifluoperazine, TFP, 20 mumol/L) also diminished the increase of H+-ATPase activity induced by NaCl. La3+, TFP or La3+ + TFP increased Na+ uptake and decreased K+ and Ca2+ uptake in barley roots under NaCl stress. These results suggested that the activation of tonoplast H+-ATPase and the regulation of Na+ and K+ uptake under NaCl stress may be related to Ca2+-CaM system.
文摘Effect of nitrate and ammonium on the activity of tonoplast pyrophosphatase (V-PPase) was investigated in the roots of tomato ( Lycopersicon esculentum L.). The results showed that the activity of V-PPase was increased by ammonium nutrition, compared with nitrate nutrition. The H+ transport of tonoplast vesicles by V-PPase was also stimulated by ammonium nutrition. The result of Western blot indicated that the protein amount of V-PPase was increased by ammonium nutrition.
文摘To study the function and adaptive mechanism of tonoplast H + ATPase under salt stress, pea ( Pisum sativum L.) seedlings were treated with different concentrations of salt (100-250 mmol/L NaCl) and with 100 mmol/L NaCl for different days (1-3 d). The ATP hydrolytic activity and the proton transport activity and the changes of the amount of tonoplast H + ATPase (subunit A) were measured. ATP hydrolytic activity of H + ATPase prepared from plants treated with 250 mmol/L NaCl was reduced by about 25% compared to that of control plants, but that of stressed plants treated with 100 mmol/L and 200 mmol/L NaCl was unchanged. The activity from plants treated with 100 mmol/L NaCl for up to 3 d was lower than that of control plants by 20%. But the proton transport activity was increased under the same salt stresses as above. These results showed that the changes of the hydrolytic activity and the proton transport activity were not in proportion and salt stress may cause the change of the coupling ratio of H + transport activity to ATP hydrolysis. The protein amount kept unchanged and reduced a little only when pea was treated with 100 mmol/L NaCl for 3 d. These results indicated that salinity stimulated the increase of the pump efficiency of the V_ATPase from pea roots, which was due to the change of the coupling ratio, but not due to the increase of ATP hydrolysis and the amount of V_ATPase.
文摘For understanding the function of tonoplast protein in plant cell signal pathway, we have identified an integral protein kinase activity from the highly purified tonoplast isolated from maize ( Zea mays L.) root by a new nonradioactive method in which a color labeled peptide was used as substrate. The protein kinase was Ca 2+ _dependent and CaM and phosphatidylserine_independent, like the calmodulin_like domain protein kinase (CDPK) in many plants. The optimal pH value and Ca 2+ concentration were 6.5 and 10 μmol/L, respectively. According to the optimal pH value and the effect of detergent, it could be inferred that the active site of this protein kinase is oriented toward the cytoplasm. Zn 2+ had no obvious effect on its activity, indicating that this protein kinase has no zinc_finger domain that exists in some mammalian protein kinases. At the same time, when tonoplast proteins were prephosphorylated in the presence of Ca 2+ and ATP, both the ATP_hydrolysis and the proton_transport activity of vacuolar H +_ATPase were stimulated. This stimulation could be reversed by an alkaline_phosphatase. These results indicate that a Ca 2+ _dependent protein kinase was located in the tonoplast, and a Ca 2+ _dependent phosphorylation, probably caused by this kinase, activated the vacuolar H +_ATPase activity. These results are helpful for further research on the function of CDPK in the course of signal transduction in plants.
文摘The effects of NaCl stress on the H +-ATPase, H +-PPase activity and lipid composition of plasma membrane(PM) and tonoplast(TP) vesicles isolated from roots and leaves of two soybean cultivars(Glycine max L.) differing in salt tolerance(Wenfeng7, salt-tolerant; Union, salt-sensitive) were investigated. When Wenfeng7 was treated with 0.3%(W/V) NaCl for 3 d, the H +-ATPase activities in PM and TP from roots and leaves exhibited a reduction and an enhancement, respectively. The H +-PPase activity in TP from roots also increased. Similar effects were not observed in roots of Union. In addition, the increases of phospholipid content and ratios of phospholipid to galactolipid in PM and TP from roots and leaves of Wenfeng7 may also change membrane permeability and hence affect salt tolerance.
基金supported by National Key Research and Development Program of China(2023YFD2300603,2022YFF1003100)the National Natural Science Foundation of China(32322073)+2 种基金Foundation of Hubei Hongshan Laboratory(2021hszd016)Fundamental Research Funds for the Central Universities(2662023PY011)the Huazhong Agricultural University(start-up funding to C.L.)。
文摘Fruit taste quality is greatly influenced by the content of soluble sugars,which are predominantly stored in the vacuolar lumen.However,the accumulation and regulation mechanisms of sugars in most fruits remain unclear.Recently,we established the citrus fruit vacuole proteome and discovered the major transporters localized in the vacuole membrane.Here,we demonstrated that the expression of tonoplast sugar transporter 2(CsTST2)is closely associated with sugar accumulation during sweet orange(Citrus sinensis)ripening.It was further demonstrated that CsTST2 had the function of transporting hexose and sucrose into the vacuole.Overexpression of CsTST2 resulted in an elevation of sugar content in citrus juice sac,calli,and tomato fruit,whereas the downregulation of its expression led to the reduction in sugar levels.CsTST2 was identified as interacting with CsCIPK23,which binds to the upstream calcium signal sensor protein CsCBL1.The phosphorylation of the three serine residues(Ser277,Ser337,and Ser354)in the loop region of CsTST2 by CsCIPK23 is crucial for maintaining the sugar transport activity of CsTST2.Additionally,the expression of CsCIPK23 is positively correlated with sugar content.Genetic evidence further confirmed that calcium and CsCIPK23-mediated increase in sugar accumulation depends on CsTST2 and its phosphorylation level.These findings not only unveil the functional mechanism of CsTST2 in sugar accumulation,but also explore a vital calcium signal regulation module of CsCBL1/CIPK23 for citrus sweetness quality.
基金supported by the National Natural Science Foundation of China(32341045 and 32120103010)the Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences,and the Youth Innovation Program of the Chinese Academy of Agricultural Sciences(Y2022QC05).
文摘Fruit yield and quality are antagonistically regulated traits in tomato.An excessive focus on increasing yield often leads to a decline in quality.Achieving a delicate balance between high yield and desirable fruit quality is a challenging aspect of tomato breeding.In this study,we discovered that disrupting the function of the tomato tonoplast sugar transporter 3a(TST3a)significantly enhances both fruit weight andflavor.Three TSTs have been identified in tomato,namely SlTST1,SlTST3a,and SlTST3b;they possess the same sugar transport specificity for fructose and glucose and redundantly control cell expansion during fruit develop-ment.Sugar accumulation in sltst mutants correlates significantly with fruit size andflavor.The enlarged fruits in sltst3a mutants result from sugar accumulation due to the increased abundance of SlTST1 at the tonoplast coupled with the highest sugar transport capacity of SlTST1 among the three SlTSTs.Further ex-periments established that SlTST3a prevents the localization of SlTST1 to the tonoplast by inhibiting its interaction with VH1-interacting kinase(SlVIK).Mutation of SlTST3a in cultivated tomato can enhance both tomato fruit size and sugar content.Ourfindings offer potential avenues for simultaneously improving fruit quality and yield,providing valuable insights into the mechanisms underlying sugar storage during fruit development.
文摘We have mapped the expression of the tonoplast intrinsic protein （TIP） gene family members in Arabidopsis seeds by fluorescent protein tagging of their genomic sequences and confocal microscopy. Three isoforms （TIP1;1, TIP2;1, and TIP2;2） have distinct patterns of expression in maternal tissues （outer integument and placento-chalazal region）. Two isoforms, TIP3;1 and the previously uncharacterized TIP3;2, are the only detectable TIPs in embryos during seed maturation and the early stages of seed germination. Throughout these developmental stages, both isoforms co-locate to the tono- plast of the protein storage vacuoles, but also appear to label the plasma membrane. Plasma membrane labeling is specific to TIP3;1 and TIP3;2, is independent of the position of the fluorescent protein tag, and appears to be specific to early seed maturation and early germination stages. We discuss these results in the context of the predicted distribution of aquaporins in Arabidopsis seeds.
文摘Both enhanced were H^+ transport activities of tonoplast vesicles isolated from roots of the salt-tolerant mutant and wild type of wheat with treatment of NaCI, but the activity of the mutant was significantly higher than that of wild type. H^+ transport activity was indicated as the stable value of fluorescence quenching per mg membrane proteins. The H^+ transport activities dependent on ATP of the mutant and wild type were 1099 and 558 respectively and their activities dependent on PPi were 358 and 228 separately.
基金supported by Major Research Plan(2013CB945102) from the Ministry of Science,Technology of ChinaNational Natural Science Foundation of China(31261160490 to Y.Z.)Natural Science Foundation of Shandong Province(ZR2014CM027 to S.L.)
文摘Summary Vacuolar trafficking routes and their regu- lators have recently drawn lots of attention in plant cell biology. A recent study reported the discovery of a plant-specific vacuolar trafficking route, i.e., a direct ER- to-vacuole route, through analysis of VHA-a3 subcellular targeting, a key component for the tonoplast V- ATPases. Our recent findings showed that VHA-a3 targets to the tonoplast through a Rab5-mediated but Rab7-independent pathway, shedding new lights on the unconventional vacuolar trafficking route in plant cells.
文摘Subject Code:C02With the support by the National Natural Science Foundation of China,the research team led by Prof.Lin Jinxing(林金星)at the College of Biological Sciences&Biotechnology,Beijing Forestry University,overcame the limitations of existing techniques and expanded the study of protein characteristics from the plasma membrane to the vacuole membranes.This study was published in Molecular Plant(2016,DOI:
基金supported by the National Natural Science Foundation of China (30770193)the National Basic Research Program of China (2006CB100100)the "111 Project" (B06003)
文摘Aquaporins are implicated in a wide variety of plant physiological processes, although the mechanisms involved in their regulation are not fully understood. To gain further insight into the regulatory factors involved in this process, we used a yeast two-hybrid system to screen for potential binding partners to the Arabidopsis tonoplast intrinsic protein (TIP) AtTIP1;1. This was the first protein identified to be associated with high water permeability in vacuolar membranes from Arabidopsis thaliana. Using AtTIP1;1 as bait, a novel binding protein was identified in both yeast and plant cells. This prey protein, named AtSM34, was a 309 aa polypeptide with a predicted molecular mass of 34 kD and contained a single MYB/SANT-like domain. AtSM34 promoter:: GUS histochemical staining analysis detected AtSM34 expression in flowers, stems and leaves, particularly in the vascular tissues, in response to osmotic stress. AtSM34 expression was localized in the endoplasmic reticulum membrane, and sequence deletion analysis revealed that the N-terminal coding region (amino acids 1-83) was critical for this localization. Overexpression of AtSM34 resulted in hypersensitivity to exogenous mannitol, sorbitol and abscisic acid, and caused a significant delay in germination. AtSM34 interacted with AtTIP1;2 and AtTIP2;1, which are essential proteins for modulation of tonoplast permeability and highly expressed in germinating seedlings. These data indicate AtSM34 is a novel TIPs binding protein involved in the osmotic stress response of seedlings at an early stage of development.
文摘The growth of barley (Hordeum vulgare L.) seedling is inhibited by 300 mmol/L NaCl. When 20 mg/L GSH is present in the hydroponic culture solution with NaCl, root length, root and shoot dry weigh, chlorophyll as well as K+ contents are increased, Na+ content is decreased. At the same time the activities of H+-ATPase and H+-PPase associated with tonoplast vesicles isolated from leaves are stimulated, and electrolytic leakage are diminished by exogenous GSH.
