两种生态型苔草Carex morcroftii(C.moorcroftii)植物沙生型(DC)和水生型(SC)的愈伤组织对盐度具有不同的敏感性.本研究对这两种生态类型苔草愈伤组织进行盐胁迫处理.在100 mM NaCl处理下,Na^+百分比显著增加而K^+百分比降低,导致SC愈...两种生态型苔草Carex morcroftii(C.moorcroftii)植物沙生型(DC)和水生型(SC)的愈伤组织对盐度具有不同的敏感性.本研究对这两种生态类型苔草愈伤组织进行盐胁迫处理.在100 mM NaCl处理下,Na^+百分比显著增加而K^+百分比降低,导致SC愈伤组织Na^+/K^+比值急剧增加,但DC中Na^+/K^+比值与对照相比无显著性差异.8-Br-cGMP(cGMP的一种类似物)以浓度依赖性的方式影响DC和SC的元素比值.6-苯胺-5,8-喹啉二酮(Ly83583,cGMP抑制剂)可降低内源性cGMP的浓度,通过降低K+百分比、增加Na+百分比和Na^+/K^+比来消除8-Br-cGMP的作用.DC愈伤组织中,Ly83583能够降低由于NaCl导致的PM H^+-ATPase活性的增加.然而,乙二醇-双-(2-氨基乙基醚)四乙酸(EGTA,Ca^2+螯合剂)不能改变cGMP的内源性浓度.以上结果表明,Ca^2+作为cGMP的下游信号通过降低Na^+/K^+比率和提升PM H^+-ATPase活性增强苔草愈伤组织的耐盐性.展开更多
本文克隆了RIN4(RPM1-interacting protein 4)在胡杨中的同源基因PeRIN4,并在拟南芥中进行过表达,通过研究转基因株系的耐盐表型、质膜H^+-ATPsae活性及H^+、Na^+、K^+等的动态离子流,揭示了PeRIN4基因在植物响应和适应盐胁迫环境中的...本文克隆了RIN4(RPM1-interacting protein 4)在胡杨中的同源基因PeRIN4,并在拟南芥中进行过表达,通过研究转基因株系的耐盐表型、质膜H^+-ATPsae活性及H^+、Na^+、K^+等的动态离子流,揭示了PeRIN4基因在植物响应和适应盐胁迫环境中的作用。利用定位载体p Green0029-PeRIN4-GFP瞬时转化拟南芥叶肉细胞原生质体的方法,对胡杨PeRIN4蛋白进行亚细胞定位,发现该蛋白定位在细胞的胞质中。耐盐表型实验结果显示,在100 mmol/L NaCl处理下,拟南芥PeRIN4过表达株系(OE1和OE8)的生存率和根长均明显高于野生型(WT)和转空载体拟南芥(VC),说明PeRIN4基因能够提高拟南芥的耐盐性。与WT和VC相比,拟南芥PeRIN4过表达株系质膜H^+-ATPsae的活性较高。动态离子流数据显示,在盐胁迫下,PeRIN4过表达株系外排H^+和Na^+离子的能力强于野生型和转空载体拟南芥,然而K+的外流却弱于WT和VC。因此,PeRIN4蛋白具有调节质膜H^+-ATPsae活性的功能。拟南芥质膜H^+-ATPsae活性的提高主要有两方面的作用:一是可以增强H+泵的质子动力势,驱动Na^+/H^+逆向转运蛋白,提高Na^+外排的能力;二是抑制质膜的去极化,减少K+离子通过去极化激活的外向型K^+通道(DA-KORCs)和非选择性阳离子通道(DA-NSCCs)外流,维持了K^+/Na^+平衡,从而提高PeRIN4转基因拟南芥的耐盐性。展开更多
Tonoplast-enriched vesicles were prepared from suspension-cultured Populus euphratica Oliv. cells by differential centrifugation and discontinuous sucrose density gradient centrifugation. The properties of the proton ...Tonoplast-enriched vesicles were prepared from suspension-cultured Populus euphratica Oliv. cells by differential centrifugation and discontinuous sucrose density gradient centrifugation. The properties of the proton pumping activity of H+-ATPases in tonoplast vesicles were studied by acridine orange fluorescent quenching measured at 22 degreesC. The proton pumping activity of ATPase was ATP-dependent with apparent Michaelis-Menten Constant (K-m) for ATP about 0.65 mmol/L. The optimal pH for H+-ATPases activity was 7.5. The proton pumping activity of H+-ATPase could be initiated by some divalent cations, Mg2+ being highly efficient, much more than Fe2+; and Ca2+, Cu2+ and Zn2+ were inefficient under the experimental condition. The proton translocation could be stimulated by halide anions, with potencies decreasing in the order Cl- > Br- > I- > F-. The proton pumping activity was greatly inhibited by N-ethylmaleimide (NEM), N, N'-dicyclohexylcarbodiimide (DCCD), NO3- and Bafilomycin A(1), but not by orthovanadate and azide. These results demonstrated that the H+-ATPase in the tonoplast of Populus euphratica belonged to vacuolar type ATPase. This work was the first time that tonoplast-enriched vesicles were isolated from Populus euphratica cells.展开更多
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
文摘Tonoplast-enriched vesicles were prepared from suspension-cultured Populus euphratica Oliv. cells by differential centrifugation and discontinuous sucrose density gradient centrifugation. The properties of the proton pumping activity of H+-ATPases in tonoplast vesicles were studied by acridine orange fluorescent quenching measured at 22 degreesC. The proton pumping activity of ATPase was ATP-dependent with apparent Michaelis-Menten Constant (K-m) for ATP about 0.65 mmol/L. The optimal pH for H+-ATPases activity was 7.5. The proton pumping activity of H+-ATPase could be initiated by some divalent cations, Mg2+ being highly efficient, much more than Fe2+; and Ca2+, Cu2+ and Zn2+ were inefficient under the experimental condition. The proton translocation could be stimulated by halide anions, with potencies decreasing in the order Cl- > Br- > I- > F-. The proton pumping activity was greatly inhibited by N-ethylmaleimide (NEM), N, N'-dicyclohexylcarbodiimide (DCCD), NO3- and Bafilomycin A(1), but not by orthovanadate and azide. These results demonstrated that the H+-ATPase in the tonoplast of Populus euphratica belonged to vacuolar type ATPase. This work was the first time that tonoplast-enriched vesicles were isolated from Populus euphratica cells.
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.
