The most prominent ion channel localized in plant vacuoles is the slow activating SV type. Slow vacuolar （SV） channels were discovered by patch clamp studies as early as 1986. In the following two decades, numerous ...The most prominent ion channel localized in plant vacuoles is the slow activating SV type. Slow vacuolar （SV） channels were discovered by patch clamp studies as early as 1986. In the following two decades, numerous studies revealed that these calcium- and voltage-activated, nonselective cation channels are expressed in the vacuoles of all plants and every plant tissue. The voltage-dependent properties of the SV channel are susceptible to modulation by calcium, pH, redox state, as well as regulatory proteins. In Arabidopsis, the SV channel is encoded by the AtTPC1 gene, and even though its gene product represents the by far largest conductance of the vacuolar membrane, tpcl-loss-of-function mutants appeared not to be impaired in major physiological functions such as growth, development, and reproduction. In contrast, the fou2 gain-of-function point mutation D454N within TPC1 leads to a pronounced growth phenotype and increased synthesis of the stress hormone jasmonate. Since the TPC1 gene is present in all land plants, it likely encodes a very general function. In this review, we will discuss major SV channel properties and their impact on plant cell physiology.展开更多
Plants and animals in endosomes operate TPCI/SV-type cation channels. All plants harbor at least one TPC1 gene. Although the encoded SV channel was firstly discovered in the plant vacuole membrane two decades ago, its...Plants and animals in endosomes operate TPCI/SV-type cation channels. All plants harbor at least one TPC1 gene. Although the encoded SV channel was firstly discovered in the plant vacuole membrane two decades ago, its biological function has remained enigmatic. Recently, the structure of a plant TPC1/SV channel protein was determined. Insights into the 3D topology has now guided site-directed mutation ap- proaches, enabling structure-function analyses of TPC1/SV channels to shed new light on earlier findings. Fou2 plants carrying a hyperactive mutant form of TPC1 develop wounding stress phenotypes. Recent studies with fou2 and mutants that lack functional TPC1 have revealed atypical features in local and long-distance stress signaling, providing new access to the previously mysterious biology of this vacuolar cation channel type in planta.展开更多
We recorded slow vacuolar (SV-type) channel currents of Radish vacuoles successfully for the first time by using the whole-vacuolar patch-clamp recording mode. SV-type currents would increase and threshold potentials ...We recorded slow vacuolar (SV-type) channel currents of Radish vacuoles successfully for the first time by using the whole-vacuolar patch-clamp recording mode. SV-type currents would increase and threshold potentials of activation would shift towards more negative values with the increase of concentrations of cytosolic Ca2+. When 2.5 mmol/ L LaCl3 and 4 mmol/L EGTA were added to bath solutions, SV-type currents were suppressed remarkably. Then adding LaCl3 with different concentrations to pipette solutions, we found that LaCl3 with higher concentrations (】4 × 10-7mol/L) had a strong inhibitory effect on SV-type currents, while LaCl3 with lower concentrations (≤4 × 10-7mol/L) promoted channel currents. This promoting effect provides an impor-tant basis at channel level for researching further the effects of rare earth on physiological activities of plants and the production-increase effects of rare earth fertilizers on crops.展开更多
Applying the patch-clamp technique to vacuoles from Radish we studied the effects of Cu2+ on Slow Vacuolar (SV) current’s characteristic. Our results show that Cu2+ in bath solution at higher concentration inhibits S...Applying the patch-clamp technique to vacuoles from Radish we studied the effects of Cu2+ on Slow Vacuolar (SV) current’s characteristic. Our results show that Cu2+ in bath solution at higher concentration inhibits SV currents and the percentage of inhibition increases with increasing concentration and changes with different voltage. When at lower concentration, Cu2+ significantly promotes the SV currents and the promotion ratio decrease with increasing voltage. At the same time, the time constants of activation become lesser after adding Cu2+. These results show that there may be some Cu2+ binding sites on SV channels and binding to which can change SV current’s characteristic.展开更多
文摘The most prominent ion channel localized in plant vacuoles is the slow activating SV type. Slow vacuolar （SV） channels were discovered by patch clamp studies as early as 1986. In the following two decades, numerous studies revealed that these calcium- and voltage-activated, nonselective cation channels are expressed in the vacuoles of all plants and every plant tissue. The voltage-dependent properties of the SV channel are susceptible to modulation by calcium, pH, redox state, as well as regulatory proteins. In Arabidopsis, the SV channel is encoded by the AtTPC1 gene, and even though its gene product represents the by far largest conductance of the vacuolar membrane, tpcl-loss-of-function mutants appeared not to be impaired in major physiological functions such as growth, development, and reproduction. In contrast, the fou2 gain-of-function point mutation D454N within TPC1 leads to a pronounced growth phenotype and increased synthesis of the stress hormone jasmonate. Since the TPC1 gene is present in all land plants, it likely encodes a very general function. In this review, we will discuss major SV channel properties and their impact on plant cell physiology.
文摘Plants and animals in endosomes operate TPCI/SV-type cation channels. All plants harbor at least one TPC1 gene. Although the encoded SV channel was firstly discovered in the plant vacuole membrane two decades ago, its biological function has remained enigmatic. Recently, the structure of a plant TPC1/SV channel protein was determined. Insights into the 3D topology has now guided site-directed mutation ap- proaches, enabling structure-function analyses of TPC1/SV channels to shed new light on earlier findings. Fou2 plants carrying a hyperactive mutant form of TPC1 develop wounding stress phenotypes. Recent studies with fou2 and mutants that lack functional TPC1 have revealed atypical features in local and long-distance stress signaling, providing new access to the previously mysterious biology of this vacuolar cation channel type in planta.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 29890280).
文摘We recorded slow vacuolar (SV-type) channel currents of Radish vacuoles successfully for the first time by using the whole-vacuolar patch-clamp recording mode. SV-type currents would increase and threshold potentials of activation would shift towards more negative values with the increase of concentrations of cytosolic Ca2+. When 2.5 mmol/ L LaCl3 and 4 mmol/L EGTA were added to bath solutions, SV-type currents were suppressed remarkably. Then adding LaCl3 with different concentrations to pipette solutions, we found that LaCl3 with higher concentrations (】4 × 10-7mol/L) had a strong inhibitory effect on SV-type currents, while LaCl3 with lower concentrations (≤4 × 10-7mol/L) promoted channel currents. This promoting effect provides an impor-tant basis at channel level for researching further the effects of rare earth on physiological activities of plants and the production-increase effects of rare earth fertilizers on crops.
基金support by the National Natural Science Foun-dation of China(Grant No.20637010)the Shanxi Pro-vincial Natural Science Foundation for Youth(Grant No.20041032).
文摘Applying the patch-clamp technique to vacuoles from Radish we studied the effects of Cu2+ on Slow Vacuolar (SV) current’s characteristic. Our results show that Cu2+ in bath solution at higher concentration inhibits SV currents and the percentage of inhibition increases with increasing concentration and changes with different voltage. When at lower concentration, Cu2+ significantly promotes the SV currents and the promotion ratio decrease with increasing voltage. At the same time, the time constants of activation become lesser after adding Cu2+. These results show that there may be some Cu2+ binding sites on SV channels and binding to which can change SV current’s characteristic.
