Cation exchangers （CAXs） belong to the cation/Ca2＋exchanger superfamily which have been extensively investigated in plant tonoplasts over the last decade. Recently, the roles of CAXs involved in heavy metal accumul...Cation exchangers （CAXs） belong to the cation/Ca2＋exchanger superfamily which have been extensively investigated in plant tonoplasts over the last decade. Recently, the roles of CAXs involved in heavy metal accumulation and tolerance in plants have been studied for phytoremediation and food security. In this mini review, we summarize the roles of the Ca2＋/H＋ antiporter in Ca2＋ signal transduction, maintaining ion homeostasis and sequestering heavy metals into the vacuole. Moreover, we present a possible role of the plasma membrane Ca2＋/H＋ antiporter in heavy metal detoxification.展开更多
On the basis of two types of calcium transport system detected in the barley root plasma membrane,the mechanisms of the calcium transport have been further studied.Ionophore CCCP has been found to inhibit Mg^(2+) -dep...On the basis of two types of calcium transport system detected in the barley root plasma membrane,the mechanisms of the calcium transport have been further studied.Ionophore CCCP has been found to inhibit Mg^(2+) -dependent calcium transport by 20%.In contrast,Mg^(2+) -independent calcium trans- port is insensitive to CCCP.The Mg^(2+) -dependent calcium transport following the collapse of H^+ gradient across the plasma membrane could be driven by the H^+ gradient either set up by ATP or imposed artificially. Any relation between Mg^(2+) -independent calcium transport and H^+ gradient has not been observed.These results indicate that Mg^(2+) -dependent calcium transport is accompanied by the decrease of H^+ gradient,and Mg^(2+) -independent calcium transport has nothing to do with the H^+ gradient.It is therefore suggested that the calcium transport across the barley root plasma membrane is driven by ATPase that is independent of Mg^(2+),and H^+/Ca^(2+) antiporter that is dependent on Mg^(2+).展开更多
The plant NHX gene family encodes Na＋/H＋ antiporters which are crucial for salt tolerance, potassium homeostasis and cellular pH regulation. Understanding the role of NHX antiporters in membrane trafficking is becom...The plant NHX gene family encodes Na＋/H＋ antiporters which are crucial for salt tolerance, potassium homeostasis and cellular pH regulation. Understanding the role of NHX antiporters in membrane trafficking is becoming an increasingly interesting subject of study. Membrane trafficking is a central cellular process during which proteins, lipids and polysaccharides are continuously exchanged among membrane compartments. Yeast ScNhxlp, a prevacuole/ vacuolar Na＋/H＋ antiporter, plays an important role in regulating pH to control trafficking out of the endosome. Evidence begins to accumulate that plant NHX antiporters might function in regulating membrane trafficking in plants.展开更多
Brassica chinensis L. were foliarly applied with glycinebetaine (GB), as this species is unable to synthesis GB and sensitive to osmotic stress such as salt. The exogenous GB was easily absorbed and transported by t...Brassica chinensis L. were foliarly applied with glycinebetaine (GB), as this species is unable to synthesis GB and sensitive to osmotic stress such as salt. The exogenous GB was easily absorbed and transported by the leaf of B. chinensis . Its application (0-20 mmol/L) enhanced the plant tolerance to salt stress. The treatment of 15 mmol/L GB significantly decreased the Na + accumulation in leaf and root under NaCl stress. This difference in accumulating Na + and K + is caused by higher selectivity of root absorption. Furthermore, GB increased H +_ATPase activity of root plasma membrane evidently. This result strongly suggested that in root the decreased Na + accumulation was caused by the GB accumulation that enhanced the extrusion of Na + from the cell in some way through plasma membrane transporter, e.g. Na +/H + antiport driven by H +_ATPase. The GB application was also found to stabilize the plasma membrane, to decrease the loss of chlorophyll, and to stimulate the osmosis induced proline response under salt stress.展开更多
With 200 mmol/L NaCl treatment on barley cultivar 'Jian 4' (Hordeum vulgare L. cv. J4) seedlings for 6 d, the contents of covalently and noncovalently conjugated polyamines (PAs) and activities of H+-ATPase in...With 200 mmol/L NaCl treatment on barley cultivar 'Jian 4' (Hordeum vulgare L. cv. J4) seedlings for 6 d, the contents of covalently and noncovalently conjugated polyamines (PAs) and activities of H+-ATPase in plasma membrane (PM) vesicles isolated from the roots decreased remarkably. Moreover, the activity of Na+/H+ antiport was detected first in PM vesicles. The results showed that the decrease in the contents of membrane phospholipid, noncovalently conjugated PAs and activity of H+-ATPase caused by NaCl could be restored partially by application of 1 mmol/L stearic acid (C16:0) and linoleic acid (C18:2), and C18:2 was more effective than C16:0. In addition, a reduction in the contents of covalently conjugated PAs was only reversed partially in the presence of C18:2. Furthermore, Na+/H+ antiport activity was strengthened by exogenous C16:0 and C18:2, and C18:2 was more effective than C16:0. The correlative analysis suggested that, after application of C16:0 and C18:2 under salt stress, there was a展开更多
基金supported by grants from the National Science Foundation of China (Grant No.20977084)the Natural Science Foundation of Zhejiang Province,China (Grant No. R507719)a Project of the National Key Basic Research and Development of China (Grant No. 2007CB109305)
文摘Cation exchangers （CAXs） belong to the cation/Ca2＋exchanger superfamily which have been extensively investigated in plant tonoplasts over the last decade. Recently, the roles of CAXs involved in heavy metal accumulation and tolerance in plants have been studied for phytoremediation and food security. In this mini review, we summarize the roles of the Ca2＋/H＋ antiporter in Ca2＋ signal transduction, maintaining ion homeostasis and sequestering heavy metals into the vacuole. Moreover, we present a possible role of the plasma membrane Ca2＋/H＋ antiporter in heavy metal detoxification.
文摘On the basis of two types of calcium transport system detected in the barley root plasma membrane,the mechanisms of the calcium transport have been further studied.Ionophore CCCP has been found to inhibit Mg^(2+) -dependent calcium transport by 20%.In contrast,Mg^(2+) -independent calcium trans- port is insensitive to CCCP.The Mg^(2+) -dependent calcium transport following the collapse of H^+ gradient across the plasma membrane could be driven by the H^+ gradient either set up by ATP or imposed artificially. Any relation between Mg^(2+) -independent calcium transport and H^+ gradient has not been observed.These results indicate that Mg^(2+) -dependent calcium transport is accompanied by the decrease of H^+ gradient,and Mg^(2+) -independent calcium transport has nothing to do with the H^+ gradient.It is therefore suggested that the calcium transport across the barley root plasma membrane is driven by ATPase that is independent of Mg^(2+),and H^+/Ca^(2+) antiporter that is dependent on Mg^(2+).
基金supported by a grant from the National Natural Science Foundation of China (31070222 to Quan-Sheng Qiu)
文摘The plant NHX gene family encodes Na＋/H＋ antiporters which are crucial for salt tolerance, potassium homeostasis and cellular pH regulation. Understanding the role of NHX antiporters in membrane trafficking is becoming an increasingly interesting subject of study. Membrane trafficking is a central cellular process during which proteins, lipids and polysaccharides are continuously exchanged among membrane compartments. Yeast ScNhxlp, a prevacuole/ vacuolar Na＋/H＋ antiporter, plays an important role in regulating pH to control trafficking out of the endosome. Evidence begins to accumulate that plant NHX antiporters might function in regulating membrane trafficking in plants.
文摘Brassica chinensis L. were foliarly applied with glycinebetaine (GB), as this species is unable to synthesis GB and sensitive to osmotic stress such as salt. The exogenous GB was easily absorbed and transported by the leaf of B. chinensis . Its application (0-20 mmol/L) enhanced the plant tolerance to salt stress. The treatment of 15 mmol/L GB significantly decreased the Na + accumulation in leaf and root under NaCl stress. This difference in accumulating Na + and K + is caused by higher selectivity of root absorption. Furthermore, GB increased H +_ATPase activity of root plasma membrane evidently. This result strongly suggested that in root the decreased Na + accumulation was caused by the GB accumulation that enhanced the extrusion of Na + from the cell in some way through plasma membrane transporter, e.g. Na +/H + antiport driven by H +_ATPase. The GB application was also found to stabilize the plasma membrane, to decrease the loss of chlorophyll, and to stimulate the osmosis induced proline response under salt stress.
基金We are grateful to Prof. Huang Huacheng (School of Academic Science, Shandong Agricultural University) for his useful suggestions This work is a part of post doctoral work of the author.
文摘With 200 mmol/L NaCl treatment on barley cultivar 'Jian 4' (Hordeum vulgare L. cv. J4) seedlings for 6 d, the contents of covalently and noncovalently conjugated polyamines (PAs) and activities of H+-ATPase in plasma membrane (PM) vesicles isolated from the roots decreased remarkably. Moreover, the activity of Na+/H+ antiport was detected first in PM vesicles. The results showed that the decrease in the contents of membrane phospholipid, noncovalently conjugated PAs and activity of H+-ATPase caused by NaCl could be restored partially by application of 1 mmol/L stearic acid (C16:0) and linoleic acid (C18:2), and C18:2 was more effective than C16:0. In addition, a reduction in the contents of covalently conjugated PAs was only reversed partially in the presence of C18:2. Furthermore, Na+/H+ antiport activity was strengthened by exogenous C16:0 and C18:2, and C18:2 was more effective than C16:0. The correlative analysis suggested that, after application of C16:0 and C18:2 under salt stress, there was a
