共查询到20条相似文献,搜索用时 31 毫秒
1.
L. Yang H. Liu S. M. Fu H. M. Ge R. J. Tang Y. Yang H. H. Wang H. X. Zhang 《Biologia Plantarum》2017,61(4):641-650
The tonoplast and plasma membrane localized sodium (potassium)/proton antiporters have been shown to play an important role in plant resistance to salt stress. In this study, AtNHX1 and AtNHX3, two tonoplast Na+(K+)/H+ antiporter encoding genes from Arabidopsis thaliana, were expressed in poplar to investigate their biological functions in the resistance to abiotic stresses in woody plants. Transgenic poplar plants expressing either gene exhibited increased resistance to both salt and water-deficit stresses. Compared to the wild type (WT) plants, transgenic plants accumulated more sodium and potassium ions in the presence of 100 mM NaCl and showed reduced electrolyte leakage in the leaves under water stress. Furthermore, the proton-translocating and cation-dependent H+ (Na+/H+ or K+/H+) exchange activities in the tonoplast vesicles isolated from the leaves of transgenic plants were higher than in those isolated from WT plants. Therefore, constitutive expression of either AtNHX1 or AtNHX3 genetically modified the salt and water stress tolerance of transgenic poplar plants, providing a potential tool for engineering tree species with enhanced resistance to multiple abitotic stresses. 相似文献
2.
Tazawa M 《Journal of plant research》2003,116(5):419-442
This article deals with cell physiological aspects of the plasma membrane electrogenic proton (H+) pump and emphasizes the contribution of the giant algal cells of the Characeae in elucidating the mechanism of the pump. First, a history of the development of intracellular perfusion techniques in characean internodal cells is described, including preparation of tonoplast-free cells. Then, an outline of the hypothesis of the electrogenic H+ pump proposed by Kitasato is introduced, who prophesied the existence of an electric potential generated by an active H+ efflux. Subsequently, a history of finding ATP as the direct energy source of the electrogenic ion pump is presented. Quantitative agreement between the pump current and the ATP-dependent H+ efflux supports the notion that the ion carried by the electrogenic ion pump is H+. The role of the H+ pump in regulation of the cytosolic pH is discussed. Mechanisms of light-induced potential change through photosynthesis-controlled activation of the H+ pump are discussed in terms of changes in the levels of adenine nucleotides and in modulation of the Km value for the ATP of H+-ATPase. Recent progress in the molecular mechanism of the blue-light-induced activation of the H+-ATPase in guard cells is presented. However, there are cases where H+-ATPase activity is inhibited by blue light, indicating the flexibility of the control mechanisms of H+-ATPase activity. Finally, modulation of H+-pumping or H+-ATPase activities in response to environmental factors, such as anoxia, membrane excitation, osmotic and salt stresses, nutrient deficiencies and aluminum toxicity are described. Discussions are presented on the regulation of the electrogenic H+ pump. 相似文献
3.
Sodium proton antiporters are ubiquitous membrane proteins that catalyze the exchange of Na+ for protons throughout the biological world. The Escherichia coli NhaA is the archetypal Na+/H+ antiporter and is absolutely essential for survival in high salt concentrations under alkaline conditions. Its crystal structure,
accompanied by extensive molecular dynamics simulations, have provided an atomically detailed model of its mechanism. In this
study, we utilized a combination of computational methodologies in order to construct a structural model for the Na+/H+ antiporter from the gram-negative bacterium Vibrio parahaemolyticus. We explored its overall architecture by computational means and validated its stability and robustness. This protein belongs
to a novel group of NhaA proteins that transports not only Na+ and Li+ as substrate ions, but K+ as well, and was also found to miss a β-hairpin segment prevalent in other homologs of the Bacteria domain. We propose, for the first time, a structure of a prototype model of a β-hairpin-less NhaA that is selective to K+. Better understanding of the Vibrio parahaemolyticus NhaA structure-function may assist in studies on ion transport, pH regulation and designing selective blockers. 相似文献
4.
T. V. Roslyakova E. M. Lazareva N. V. Kononenko A. V. Babakov 《Biochemistry. Biokhimii?a》2009,74(5):549-556
The gene HvNHX3 encoding a new isoform of vacuolar Na+/H+-antiporter was identified in barley. This gene is expressed in roots and leaves of barley seedlings, and it encodes a protein consisting of 541 amino acid residues with pre-dicted molecular weight 59.7 kDa. It was found that by its amino acid sequence HvNHX3 is closest to the Na+/H+-antiporter HbNHX1 of wild type from Hordeum brevisibulatum that grows on salt-marsh (solonchak) soils (95% homology). The expression of HvNHX3 during salt stress is increased several-fold in roots and leaves of barley seedlings. At the same time, the amount of HvNHX3 protein in roots does not change, but in leaves it increases significantly. It was shown using HvNHX3 immunolocalization in roots that this protein is present in all tissues, but in control plants it was clustered and in experimental plants after salt stress it was visualized as small granules. It has been proposed that HvNHX3 is converted into active form during declusterization. The conversion of HvNHX3 into its active form along with its quantitative increase in leaves during salt stress activates Na+/H+-exchange across the vacuolar membrane and Na+ release from cytoplasm, and, as a consequence, an increase of salt stress tolerance. 相似文献
5.
Na+/H+ antiporters are ubiquitous membrane proteins and play a central role in cell homeostasis including pH regulation, osmoregulation,
and Na+/Li+ tolerance in bacteria. The microbial communities in extremely hypersaline soil are an important resource for isolating Na+/H+ antiporter genes. A metagenomic library containing 35,700 clones was constructed by using genomic DNA obtained from the hypersaline
soil samples of Keke Salt Lake in Northwest of China. Two Na+/H+ antiporters, K1-NhaD, and K2-NhaD belonging to NhaD family, were screened and cloned from this metagenome by complementing
the triple mutant Escherichia coli strain KNabc (nhaA
−
, nhaB
−
, chaA
−) in medium containing 0.2 M NaCl. K1-NhaD and K2-NhaD have 75.5% identity at the predicted amino acid sequence. K1-NhaD has
78% identity with Na+/H+ antiporter NhaD from Halomonas elongate at the predicted amino acid sequence. The predicted K1-NhaD is a 53.5 kDa protein (487 amino acids) with 13 transmembrane
helices. K2-NhaD has 73% identity with Alkalimonas amylolytica NhaD. The predicted K2-NhaD is a 55 kDa protein (495 amino acids) with 12 transmembrane helices. Both K1-NhaD and K2-NhaD
could make the triple mutant E. coli KNabc (nhaA
−
, nhaB
−
, chaA−) grow in the LBK medium containing 0.2–0.6 M Na+ or with 0.05–0.4 M Li+. Everted membrane vesicles prepared from E. coli KNabc cells carrying K1-NhaD or K2-NhaD exhibited Na+/H+ and Li+/H+ antiporter activities which were pH-dependent with the highest activity at pH 9.5. Little K+/H+ antiporter activity was also detected in vesicles form E. coli KNabc carrying K1-NhaD or K2-NhaD. 相似文献
6.
7.
Increasing evidences have indicated that humic substances can induce plant growth and productivity by functioning as an environmental
source of auxinic activity. Here we comparatively evaluate the effects of indole-3-acetic acid (IAA) and humic acids (HA)
isolated from two different soils (Inseptsol and Ultisol) and two different organic residues (vermicompost and sewage sludge)
on root development and on activities of plasmalemma and tonoplast H+ pumps from maize roots. The data show that HA isolated from these different sources as well as low IAA concentrations (10−10 and 10−15 M) improve root growth through a markedly proliferation of lateral roots along with a differential activation not only of
the plasmalemma but also of vacuolar H+-ATPases and H+-pyrophosphatase. Further, the vacuolar H+-ATPase had a peak of stimulation in a range from 10−8 to 10−10 M IAA, whereas the H+-pyrophosphatase was sensitive to a much broader range of IAA concentrations from 10−3 to 10−15 M. It is proposed a complementary view of the acid growth mechanism in which a concerted activation of the plasmalemma and
tonoplast H+ pumps plays a key role in the root cell expansion process driven by environment-derived molecules endowed with auxinic activity,
such as that of humic substances. 相似文献
8.
S. O. Dodonova N. A. Krupenina A. A. Bulychev 《Biochemistry (Moscow) Supplemental Series A: Membrane and Cell Biology》2010,4(4):389-396
Photosynthesizing cells of characean algae exposed to light are able to produce pH bands corresponding to alternate areas
with dominant H+-pump activity and high H+-conductance of the cell membrane. The action potential generation temporally arrests the counter-directed H+ fluxes, which gives rise to opposite pH shifts in different cell regions and represents a suitable indicator for activities
of the plasma membrane H+-transporting systems. Measurements of pH near the cell surface by means of microelectrodes and microspectrophotometry in
the presence of pH-indicating dye thymol blue have shown that the treatment of cells with dithiothreitol (SH-group reducing
agent) suppresses pH changes induced by the action potential generation in the alkaline cell areas and considerably increases
the concurrent pH changes in the acid regions. Measurements of plasma membrane resistance in the alkaline zones revealed that
dithiothreitol inhibits the light-dependent conductance of the resting cell and diminishes the conductance inactivation caused
by the action potential generation. The data suggest that the reduction of accessible disulfide bonds results in the decrease
of H+-conductance, whereas the activity of plasma membrane H+-pump remains unimpaired or is even enhanced. 相似文献
9.
Jia Ning Yu Jian Huang Zi Ning Wang Jin Song Zhang Shou Yi Chen 《Journal of biosciences》2007,32(2):1153-1161
A vacuole Na+/H+ antiporter gene TaNHX2 was obtained by screening the wheat cDNA library and by the 5′-RACE method. The expression of TaNHX2 was induced in roots and leaves by treatment with NaCl, polyethylene glycol (PEG), cold and abscisic acid (ABA). When expressed in a yeast mutant (Δnhx1), TaNHX2 suppressed the salt sensitivity of the mutant, which was deficient in vacuolar Na+/H+ antiporter, and caused partial recovery of growth of Δnhx1 in NaCl and LiC1 media. The survival rate of yeast cells was improved by overexpressing the TaNHX2 gene under NaCl, KCl, sorbitol and freezing stresses when compared with the control. The results imply that TaNHX2 might play an important role in salt and osmotic stress tolerance in plant cells. 相似文献
10.
We previously cloned a vacuolar Na+/H+ antiporter gene (OsNHX1) from rice (Oryza sativa). Here we identified four additional NHX-type antiporter genes in rice (OsNHX2 through OsNHX5) and performed molecular and functional analyses of those genes. The exon–intron structure of the OsNHX genes and the phylogenetic tree of the OsNHX proteins suggest that the OsNHX proteins are categorized into two subgroups
(OsNHX1 through OsNHX4 and OsNHX5). OsNHX1, OsNHX2, OsNHX3, and OsNHX5 can suppress the Na+, Li+, and hygromycin sensitivity of yeast nhx1 mutants and their sensitivity to a high K+ concentration. The expression of OsNHX1, OsNHX2, OsNHX3, and OsNHX5 is regulated differently in rice tissues and is increased by salt stress, hyperosmotic stress, and ABA. When we studied the
expression of β-glucuronidase (GUS) driven by either the OsNHX1 or the OsNHX5 promoter, we observed activity in the stele, the emerging part of lateral roots, the vascular bundle, the water pore, and
the basal part of seedling shoots with both promoters. In addition, each promoter had a unique expression pattern. OsNHX1 promoter–GUS activity only was localized to the guard cells and trichome, whereas OsNHX5 promoter–GUS activity only was localized to the root tip and pollen grains. Our results suggest that the members of this gene family play
important roles in the compartmentalization into vacuoles of the Na+ and K+ that accumulate in the cytoplasm and that the differential regulation of antiporter gene expression in different rice tissues
may be an important factor determining salt tolerance in rice. 相似文献
11.
R. V. Lun'kov I. M. Andreev N. A. Myasoedov G. F. Khailova E. B. Kurkova Yu. V. Balnokin 《Russian Journal of Plant Physiology》2005,52(5):635-644
A membrane fraction enriched in plasma membrane (PM) vesicles was isolated from the root cells of a salt-accumulating halophyte Suaeda altissima (L.) Pall. by means of centrifugation in discontinuous sucrose density gradient. The PM vesicles were capable of generating ΔpH at their membrane and the transmembrane electric potential difference (Δψ). These quantities were measured with optical probes, acridine orange and oxonol VI, sensitive to ΔpH and Δψ, respectively. The ATP-dependent generation of ΔpH was sensitive to vanadate, an inhibitor of P-type ATPases. The results contain evidence for the functioning of H+-ATPase in the PM of the root cells of S. altissima. The addition of Na+ and Li+ ions to the outer medium resulted in dissipation of ΔpH preformed by the H+-ATPase, which indicates the presence in PM of the functionally active Na+/H+ antiporter. The results are discussed with regard to involvement of the Na+/H+ antiporter and the PM H+-ATPase in loading Na+ ions into the xylem of S. altissima roots. 相似文献
12.
Wei-Wei Zhang Jing-Jing Meng Jin-Yi Xing Sha Yang Feng Guo Xin-Guo Li Shu-Bo Wan 《Journal of Plant Biology》2017,60(3):259-267
High salinity is the one of important factors limiting plant growth and crop production. Many NHX-type antiporters have been reported to catalyze K+/H+ exchange to mediate salt stress. This study shows that an NHX gene from Arachis hypogaea L. has an important role in K+ uptake and transport, which affects K+ accumulation and plant salt tolerance. When overexpressing AhNHX1, the growth of tobacco seedlings is improved with longer roots and a higher fresh weight than the wild type (WT) under NaCl treatment. Meanwhile, when exposed to NaCl stress, the transgenic seedlings had higher K+/H+ antiporter activity and their roots got more K+ uptake. NaCl stress could induce higher K+ accumulation in the roots, stems, and leaves of transgenic tobacco seedlings but not Na+ accumulation, thus, leading to a higher K+/Na+ ratio in the transgenic seedlings. Additionally, the AKT1, HAK1, SKOR, and KEA genes, which are involved in K+ uptake or transport, were induced by NaCl stress and kept higher expression levels in transgenic seedlings than in WT seedlings. The H+-ATPase and H+-PPase activities were also higher in transgenic seedlings than in the WT seedlings under NaCl stress. Simultaneously, overexpression of AhNHX1 increased the relative distribution of K+ in the aerial parts of the seedlings under NaCl stress. These results showed that AhNHX1 catalyzed the K+/H+ antiporter and enhanced tobacco tolerance to salt stress by increasing K+ uptake and transport. 相似文献
13.
Aporn Bualuang Kanteera Soontharapirakkul Aran Incharoensakdi 《Journal of applied phycology》2010,22(2):123-129
The activity of Na+/H+ exchanger to remove toxic Na+ is important for growth of organisms under high salinity. In this study, the halotolerant cyanobacterium Aphanothece halophytica was shown to possess Na+/H+ exchange activity since exogenously added Na+ could dissipate a pre-formed pH gradient, and decrease extracellular pH. Kinetic analysis yielded apparent K
m (Na+) and V
max of 20.7 ± 3.1 mM and 3,333 ± 370 nmol H+ min−1 mg−1, respectively. For cells grown under salt-stress condition, the apparent K
m (Na+) and V
max was 18.3 ± 3.5 mM and 3,703 ± 350 nmol H+ min−1 mg−1, respectively. Three cations with decreasing efficiency namely Li+, Ca2+, and K+ were also able to dissipate pH gradient. Only marginal exchange activity was observed for Mg2+. The exchange activity was strongly inhibited by Na+-gradient dissipators, monensin, and sodium ionophore as well as by CCCP, a protonophore. A. halophytica showed high Na+/H+ exchange activity at neutral and alkaline pH up to pH 10. Cells grown at pH 7.6 under high salinity exhibited higher Na+/H+ exchange activity than those grown under low salinity during 15 days of growth suggesting a role of Na+/H+ exchanger for salt tolerance in A. halophytica. Cells grown at alkaline pH of 9.0 also exhibited a progressive increase of Na+/H+ exchange activity during 15 days of growth. 相似文献
14.
Plasma membrane (PM) H+-ATPase and NADPH oxidase (NOX) are two key enzymes responsible for cell wall relaxation during elongation growth through apoplastic acidification and production of ˙OH radical via O2˙?, respectively. Our experiments revealed a putative feed-forward loop between these enzymes in growing roots of Vigna radiata (L.) Wilczek seedlings. Thus, NOX activity was found to be dependent on proton gradient generated across PM by H+-ATPase as evident from pharmacological experiments using carbonyl cyanide m-chlorophenylhydrazone (CCCP; protonophore) and sodium ortho-vanadate (PM H+-ATPase inhibitor). Conversely, H+-ATPase activity retarded in response to different ROS scavengers [CuCl2, N, N’ –dimethylthiourea (DMTU) and catalase] and NOX inhibitors [ZnCl2 and diphenyleneiodonium (DPI)], while H2O2 promoted PM H+-ATPase activity at lower concentrations. Repressing effects of Ca+2 antagonists (La+3 and EGTA) on the activity of both the enzymes indicate its possible mediation. Since, unlike animal NOX, the plant versions do not possess proton channel activity, harmonized functioning of PM H+-ATPase and NOX appears to be justified. Plasma membrane NADPH oxidase and H+-ATPase are functionally synchronized and they work cooperatively to maintain the membrane electrical balance while mediating plant cell growth through wall relaxation. 相似文献
15.
CHANG-SHUI WANG QIAN-TAO JIANG JIAN MA XIU-YING WANG JI-RUI WANG GUO-YUE CHEN PENG-FEI QI YUAN-YING PENG XIU-JIN LAN YOU-LIANG ZHENG YU-MING WEI 《Journal of genetics》2016,95(3):565-572
The H+-pyrophosphatase (H +-PPase) gene plays an important role in maintaining intracellular proton gradients. Here, we characterized the full-length complementary DNA (cDNA) and DNA of the H +-PPase gene ScHP1 in rye (Secale cereale L. ‘Qinling’). We determined the subcellular localization of this gene and predicted the corresponding protein structure. We analysed the evolutionary relationship between ScHP1 and H +?PPase genes in other species, and did real-time quantitative polymerase chain reaction to explore the expression patterns of ScHP1 in rye plants subjected to N, P and K deprivation and to cold, high-salt and drought stresses. ScHP1 cDNA included a 2289 bp open reading frame (ORF) encoding 762 amino acid residues with 14 transmembrane domains. The genomic ScHP1 DNA was 4354 bp and contained eight exons and seven introns. ScHP1 was highly homologous with other members of the H +-PPase gene family. When the full-length ORF was inserted into the expression vector pA7-YFP, the fluorescent microscopy revealed that ScHP1-YFP fusion protein was located in the plasma membrane. Rye plants that were subjected to N deprivation, cold and high-salt stresses, ScHP1 expression was higher in the leaves than roots. Conversely, plants subjected to P and K deprivation and drought stress, ScHP1 expression was higher in the roots than leaves. Under all the investigated stress conditions, expression of ScHP1 was lower in the stem than in the leaves and roots. Our results imply that ScHP1 functions under abiotic stress response. 相似文献
16.
17.
Chunxia Wu Xiuhua Gao Xiangqiang Kong Yanxiu Zhao Hui Zhang 《Plant Molecular Biology Reporter》2009,27(1):1-12
Na+/H+ exchanger catalyzes the countertransport of Na+ and H+ across membranes. Using the rapid amplification of cDNA ends method, a Na+/H+ antiporter gene (ThNHX1) was isolated from a halophytic plant, salt cress (Thellungiella halophila). The deduced amino acid sequence contained 545 amino acid residues with a conserved amiloride-binding domain (87LFFIYLLPPI96) and shared more than 94% identity with that of AtNHX1 from Arabidopsis thaliana. The ThNHX1 mRNA level was upregulated by salt and other stresses (abscisic acid, polyethylene glycol, and high temperature). This gene
partially complemented the Na+/Li+-sensitive phenotype of a yeast mutant that was deficient in the endosomal–vacuolar Na+/H+ antiporter ScNHX1. Overexpression of ThNHX1 in Arabidopsis increased salt tolerance of transgenic plants compared with the wild-type plants. In addition, the silencing of ThNHX1 gene in T. halophila caused the transgenic plants to be more salt and osmotic sensitive than wild-type plant. Together, these results suggest
that ThNHX1 may function as a tonoplast Na+/H+ antiporter and play an important role in salt tolerance of T. halophila.
Chunxia Wu, Xiuhua Gao, and Xiangqiang Kong contributed equally to this work. 相似文献
18.
19.
Our previous investigations have established that Na+ translocation across the Tetraselmis viridis plasma membrane (PM) mediated by the primary ATP-driven Na+-pump, Na+-ATPase, is accompanied by H+ counter-transport [Y.V. Balnokin et al. (1999) FEBS Lett 462:402–406]. The hypothesis that the Na+-ATPase of T. viridis operates as an Na+/H+ exchanger is tested in the present work. The study of Na+ and H+ transport in PM vesicles isolated from T. viridis demonstrated that the membrane-permeant anion NO3– caused (i) an increase in ATP-driven Na+ uptake by the vesicles, (ii) an increase in (Na++ATP)-dependent vesicle lumen alkalization resulting from H+ efflux out of the vesicles and (iii) dissipation of electrical potential, , generated across the vesicle membrane by the Na+-ATPase. The (Na++ATP)-dependent lumen alkalization was not significantly affected by valinomycin, addition of which in the presence of K+ abolished at the vesicle membrane. The fact that the Na+-ATPase-mediated alkalization of the vesicle lumen is sustained in the absence of the transmembrane is consistent with a primary role of the Na+-ATPase in driving H+ outside the vesicles. The findings allowed us to conclude that the Na+-ATPase of T. viridis directly performs an exchange of Na+ for H+. Since the Na+-ATPase generates electric potential across the vesicle membrane, the transport stoichiometry is mNa+/nH+, where m>n.Abbreviations BTP Bis-Tris-Propane, 1,3-bis[tris(hydroxymethyl)methylamino]-propane - CCCP Carbonyl cyanide m-chlorophenylhydrazone - DTT Dithiothreitol - NCDC 2-Nitro-4-carboxyphenyl N,N-diphenylcarbamate - PMSF Phenylmethylsulfonyl fluoride - PM Plasma membrane 相似文献
20.
The effects of osmotic stress on H+-ATPase and H+-PPase activities and the levels of covalently conjugated polyamines (CC-PAs) and noncovalently conjugated polyamines (NCC-PAs) were investigated using tonoplast vesicles isolated from the roots of wheat (Triticum aestivum L.) seedlings differing in drought-tolerance. The results showed that after polyethylene glycol (PEG) 6,000 (–0.55MPa) treatment for 7 days, seedling leaf relative water content (LRWC), relative dry weight increase rate (RDWIR) and root H+-ATPase and H+-PPase activities from the drought-sensitive cultivar Yangmai No. 9 decreased more markedly than those from the drought-tolerant cultivar Yumai No. 18. At the same time, the increase of the NCC-spermidine (NCC-Spd) and CC-putrescine (CC-Put) levels in root tonoplast vesicles from Yumai No. 18 was more obvious than that from Yangmai No. 9. Exogenous Spd treatment alleviated osmotic stress injury to Yangmai No. 9 seedlings, coupled with marked increases of tonoplast NCC-Spd levels and H+-ATPase and H+-PPase activities. Treatments with methylglyoxyl bis (guanyl hydrazone) (MGBG), an inhibitor of S-adenosylmethionine decarboxylase (SAMDC), and phenanthrolin, an inhibitor of transglutaminase (TGase), significantly inhibited the osmotically induced increases of NCC-Spd and CC-Put levels, respectively, in root tonoplast vesicles from Yumai No. 18 seedlings. Both MGBG and phenanthrolin treatments markedly promoted osmotically induced decreases of tonoplast H+-ATPase and H+-PPase activities and osmotic stress tolerance of seedlings of this cultivar. These results suggest that the NCC-Spd and CC-Put present in tonoplast vesicles isolated from wheat seedling roots might enhance the adaptation of seedlings to osmotic stress via maintenance of tonoplast H+-ATPase and H+-PPase activities. 相似文献