Os07g0666900

OsNHX1(Os07g0666900), is a Na⁺ and H⁺ exchanger in rice (Oryza sativa).

Annotated Information

Function

• OsNHX1, functions as a Na⁺‡and H⁺‡exchanger and plays important roles in salt tolerance of rice. OsNHX1 may play an important role in the salt tolerance of shoots rather than roots.

• Na⁺/H⁺‡exchanger catalyzes the countertransport of Na⁺‡and H⁺‡across membranes. Fukuda et al isolated a rice cDNA clone the deduced amino acid sequence of which had homology with a putative Na⁺/H⁺‡exchanger in Saccharomyces cerevisiae, NHX1. The sequence contains 2330 bp with an open reading frame of 1608 bp.
• OsNHX1 plays important roles in the compartment of Na⁺ from the cytoplasm of cells into the vacuoles in both of the tissues.

• Expression of OsNHX1 under the constitutive promoter Actin1D can confer enhanced salinity tolerance in transgenic rice plants. It also function towards alleviation of toxic effects of salt stress at all stages of the life cycle from seedling to maturity.

• OsNHX1 has the ability to suppress Na+, Li+ and hygromycin sensitivity of yeast nhx1 mutants and sensitivity to a high K+ concentration, a novel phenotype of the nhx1 mutants.

• The expression of OsNHX1, OsNHX2, OsNHX3, and OsNHX5 is regulated differently in rice tissues and is increased by salt stress, hyperosmotic stress, and ABA.

• OsNHX expression was also enhanced under submergence, and the levels of OsNHX1 and OsNHX5 transcripts agreed well with those of seedling vigor under submergence.

GO assignment(s): GO:0006814, GO:0006885, GO:0015299, GO:0015385, GO:0016021

Mutation

Figure 1. RT-PCR of OsNHX1-OE transgenic plants.(from reference ).

1. Overexpression lines of OsNHX1:

• T4
• T5
• T6

2. Transgenic lines：OsNHX1-OE.

3. OsNHX1-143 transgenic rice VS. wild-type:

• By using Agrobacterium- mediated transformation three independent T0 transgenic lines were produced from which Actin 1DOsNHX1-143 was found to be the most prominent event after molecular and stress tolerance analysis.

• The increased accumulation of Na+ in transgenic lines through the over-expression of OsNHX1. The increased accumulation of Na⁺‡ion in the vacuoles may be responsible for alleviating the toxic effects of excessive Na⁺ ion in the cytosol.

• In the case of variety, the transgenic line showed significantly higher spikelet number and yield compared to the wild-type. In the case of Variety x Treatment, only spikelet number was found to be significantly higher in transgenic plants compared to the wild-type

4. ena1-4△ nha1△ nhx1△:
A triple mutant strain of Saccharomyces cerevisiae lacking its own Na+-ATPases and Na+/H+ antiporters (ena1-4△ nha1△ nhx1△) was used for the expression of the Oryza sativa NHX1 gene encoding a putative vacuolar Na+/H+ exchanger.

5. Yeast nhx1 mutants lines:

• osnhx1-1
• osnhx1-2
  

nhx1 mutants were sensitive to a high K⁺ concentration in APG medium.

6. transgenic cell lines:

• 95-1-35
• 95-5-169

Expression

In young leaves, three OsNHX1-OE(T4, T5, T6) lines showed high expression by the genes of interests.

• The expression of OsNHX1 was differently expressed in roots and shoots, and was stimulated by salt stress in both of the tissues, suggesting that OsNHX1 plays important roles in the compartment of Na⁺‡from the cytoplasm of cells into the vacuoles in both of the tissues.

• Over-expression of OsNHX1 under Actin1D promoter was confirmed by semi-quantitative RT-PCR and Western Dot-Blot analyses. At 160 mM salt stress, transgenic seedlings grew well and showed minimal reduction in shoot and root length compared to controls. Leaf chlorophyll estimation assay at 160 mM NaCl showed significantly high chlorosis in wild-type in contrast to the transgenic line. After salt stress, lower K⁺/Na⁺ ratio in transgenic leaf compared to the wild-type indicated the increased Na+ accumulation in vacuoles. At reproductive stage transgenic plants showed improved yield charateristics compared to the wild-type after exposure to 60 mM NaCl stress.

• The expression of O. sativa Nhx1 antiporter in S. cerevisiae revealed that OsNhx1p is a transport system with broad substrate specificity for at least four alkali metal cations (Li⁺, Na⁺, K⁺ and Rb⁺) and that it is able to substitute the function of yeast endosomal Na⁺/H⁺-antiporter ScNhx1p.

• OsNHX1 gene encodes a vacuolar (Na⁺, K⁺)/H⁺ antiporter that has activity similar to that of the ScNHX1 protein.

• Expression of Na⁺/H⁺ exchanger gene OsNHX was also enhanced by submergence stress and the level of enhancement appeared to agree with the level of seedling vigor among the four cultivars studied, indicating the necessity of further study of its role in seedling vigor under submergence in rice.

Location

• Nass and Rao showed that NHX1 was localized in prevacuolar compartments and a member of the newly identified cluster that shared intracellular localization. In addition, NHE6 has been reported to have a mitochondrial distribution ,which suggesting that OsNHX1 is localized in the intracellular membrane.

• subcellular localization:
  

Analysis using rice cells expressing a fusion protein of OsNHX1 and green fluorescent protein and Western blot analysis using antibodies specific for OsNHX1 confirmed the localization of OsNHX1 on the tonoplasts, which indicating that the OsNHX1 gene encodes a vacuolar (Na⁺, K⁺)/H⁺ antiporter.

Evolution

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Labs working on this gene

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References

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Structured Information

Gene Name	Os07g0666900
Description	Similar to Na+/H+ antiporter NHX6
Version	NM_001067106.1 GI:115473944 GeneID:4344217
Length	4884 bp
Definition	Oryza sativa Japonica Group Os07g0666900, complete gene.
Source	Oryza sativa Japonica Group ORGANISM Oryza sativa Japonica Group Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta; Spermatophyta; Magnoliophyta; Liliopsida; Poales; Poaceae; BEP clade; Ehrhartoideae; Oryzeae; Oryza.
Chromosome	Chromosome 7
Location	Chromosome 7:28824582..28829465
Sequence Coding Region	28824892..28825065,28825168..28825286,28826171..28826268,28826391..28826450,28826549..28826595 ,28826676..28826870,28826973..28827019,28827100..28827166,28827258..28827358 ,28827462..28827563,28827641..28827779,28827857..28827919,28828060..28828143 ,28828718..28829032
Expression	GEO Profiles:Os07g0666900
Genome Context	<gbrowseImage1> name=NC_008400:28824582..28829465 source=RiceChromosome07 preset=GeneLocation </gbrowseImage1>
Gene Structure	<gbrowseImage2> name=NC_008400:28824582..28829465 source=RiceChromosome07 preset=GeneLocation </gbrowseImage2>
Coding Sequence	<cdnaseq>ggcatggggatggaggtggcggcggcgcggctgggggctctgtacacgacctccgactacgcgtcggtggtgtccatcaacctgttcgtcgcgctgctctgcgcctgcatcgtcctcggccacctcctcgaggagaatcgctgggtcaatgagtccatcaccgcgctcatcatcgggctctgcaccggcgtggtgatcttgctgatgaccaaagggaagagctcgcacttattcgtcttcagtgaggatctcttcttcatctacctcctccctccgatcatcttcaatgcaggttttcaggtaaagaaaaagcaattcttccggaatttcatgacgatcacattatttggagccgtcgggacaatgatatcctttttcacaatatctattgctgccattgcaatattcagcagaatgaacattggaacgctggatgtaggagattttcttgcaattggagccatcttttctgcgacagattctgtctgcacattgcaggtcctcaatcaggatgagacaccctttttgtacagtctggtattcggtgaaggtgttgtgaacgatgctacatcaattgtgcttttcaacgcactacagaactttgatcttgtccacatagatgcggctgtcgttctgaaattcttggggaacttcttttatttatttttgtcgagcaccttccttggagtatttgctggattgctcagtgcatacataatcaagaagctatacattggaaggcattctactgaccgtgaggttgcccttatgatgctcatggcttacctttcatatatgctggctgagttgctagatttgagcggcattctcaccgtattcttctgtggtattgtaatgtcacattacacttggcataacgtcacagagagttcaagagttacaacaaagcacgcatttgcaactctgtccttcattgctgagacttttctcttcctgtatgttgggatggatgcattggatattgaaaaatgggagtttgccagtgacagacctggcaaatccattgggataagctcaattttgctaggattggttctgattggaagagctgcttttgtattcccgctgtcgttcttgtcgaacctaacaaagaaggcaccgaatgaaaaaataacctggagacagcaagttgtaatatggtgggctgggctgatgagaggagctgtgtcgattgctcttgcttacaataagtttacaagatctggccatactcagctgcacggcaatgcaataatgatcaccagcaccatcactgtcgttctttttagcactatggtatttgggatgatgacaaagccattgatcaggctgctgctaccggcctcaggccatcctgtcacctctgagccttcatcaccaaagtccctgcattctcctctcctgacaagcatgcaaggttctgacctcgagagtacaaccaacattgtgaggccttccagcctccggatgctcctcaccaagccgacccacactgtccactactactggcgcaagttcgacgacgcgctgatgcgaccgatgtttggcgggcgcgggttcgtgcccttctcccctggatcaccaaccgagcagagccatggaggaagatga</cdnaseq>
Protein Sequence	<aaseq>GMGMEVAAARLGALYTTSDYASVVSINLFVALLCACIVLGHLLE ENRWVNESITALIIGLCTGVVILLMTKGKSSHLFVFSEDLFFIYLLPPIIFNAGFQVK KKQFFRNFMTITLFGAVGTMISFFTISIAAIAIFSRMNIGTLDVGDFLAIGAIFSATD SVCTLQVLNQDETPFLYSLVFGEGVVNDATSIVLFNALQNFDLVHIDAAVVLKFLGNF FYLFLSSTFLGVFAGLLSAYIIKKLYIGRHSTDREVALMMLMAYLSYMLAELLDLSGI LTVFFCGIVMSHYTWHNVTESSRVTTKHAFATLSFIAETFLFLYVGMDALDIEKWEFA SDRPGKSIGISSILLGLVLIGRAAFVFPLSFLSNLTKKAPNEKITWRQQVVIWWAGLM RGAVSIALAYNKFTRSGHTQLHGNAIMITSTITVVLFSTMVFGMMTKPLIRLLLPASG HPVTSEPSSPKSLHSPLLTSMQGSDLESTTNIVRPSSLRMLLTKPTHTVHYYWRKFDD ALMRPMFGGRGFVPFSPGSPTEQSHGGR</aaseq>
Gene Sequence	<dnaseqindica>311..484#587..705#1590..1687#1810..1869#1968..2014#2095..2289#2392..2438#2519..2585#2677..2777#2881..2982#3060..3198#3276..3338#3479..3562#4137..4451#acgaaaagagagagagagagaagagagttttgtagcgagctcgcgcgaatgcgaagccaaccgagagaggtctcgataccaaatcccgatttctcaacctgaatcccccccccacgttcctcgtttcaatctgttcgtctgcgaatcgaattctttgtttttttttctctaattttaccgggaattgtcgaattaggcattcaccaacgagcaagaggggagtggattggttggttaaagctccgcatcttgcggcggaaatctcgctctcttctctgcggtgggtggccggagaagtcgccgccggtgaggcatggggatggaggtggcggcggcgcggctgggggctctgtacacgacctccgactacgcgtcggtggtgtccatcaacctgttcgtcgcgctgctctgcgcctgcatcgtcctcggccacctcctcgaggagaatcgctgggtcaatgagtccatcaccgcgctcatcatcgtaagcgcacacacaccattgctgtgattgattgatcgattgattcgccattgttgctgacgcacgcttgctgctcgatgatttgcttgcttgcttgggcaggggctctgcaccggcgtggtgatcttgctgatgaccaaagggaagagctcgcacttattcgtcttcagtgaggatctcttcttcatctacctcctccctccgatcatcttcaatgcagggtaagtagaaacgcttcggcgtgttcttgctgtggttagatttcggcttcagttcttttgttggcacatggtggtgtacaaggtttttctggggattggggaatctgtttgctgctggtggtacactgtgtacgcgtggctggtttcttgtttgtttcttctgggcctagctgtctgtccgtcgatgtcttagacatggctgctagttcatactgtgcaggttgtgggtgaattttttttttgttttctctttaagacagagatggatttactctcgtcttactggcataccttgacttgccagctcgaactgctgattggtacagtatggagtagcaactgtaatcttgaccattgcatgaagcattgagaaatgctgaaagattatttgttttttaattttaattattatatattgattgactgtgcaacagcttctgtctcctagagttctactcttggtccatttacagtggttagtagtactggtcatccaacaccatgaaggcatgagagggatatggtcctgtcaagagtgatggcgtgatcaatttctgaaagaacagtggccatgctagtccgaatttggttgagcatttaatccccttttgaaggtttttgggccatccatatagatttgaagtagggttgtaggagtaaagctgaatattatgggcccatgtttgctttcacatttaggaattgcaaagtctctctttgggaaagggcacaagtcctttttgagttcagagttactctattttcgttccttttctgctttgcttgaacttttattttttttattcatataataacacaagttgctgaataattctacgggaaaaaaagcatcgtcctggtcctcacaaatatttttccatcagttttcaggtaaagaaaaagcaattcttccggaatttcatgacgatcacattatttggagccgtcgggacaatgatatcctttttcacaatatctattggtacgttctttcagaaatgattcttaattcttccgtgagttggtagtgctttcattttctgttgttccgtgtaaccttttggacttctgagattctgactctgatcaatttcttaatttcagctgccattgcaatattcagcagaatgaacattggaacgctggatgtaggagattttcttggtaagccatggctatctttctgcatgatcatgctggcactaatattgacaccatgtgagcatcatttcctcctgttgactgttatgttcaatgtgcagcaattggagccatcttttctgcgacagattctgtctgcacattgcaggttagttgaacaaattttgccatacctcgagagagacctggattcaacgtgctaatgtaatgatcttaaccccaaaacaggtcctcaatcaggatgagacaccctttttgtacagtctggtattcggtgaaggtgttgtgaacgatgctacatcaattgtgcttttcaacgcactacagaactttgatcttgtccacatagatgcggctgtcgttctgaaattcttggggaacttcttttatttatttttgtcgagcaccttccttggagtatttgtaagttgattcttaagtttcactttttacatcttactgtctgtcttgactctactgcttggttgacacatgtaaacttaatattcttcttccaccctgcaggctggattgctcagtgcatacataatcaagaagctatacattggaaggttagttaagcccaaacaaaccctcattagttaacggttttatgctcagtgttaacttggatgttggtgactgattccaggcattctactgaccgtgaggttgcccttatgatgctcatggcttacctttcatatatgctggctgaggtgtgcctctgctttgatgcagtatcaaaatttgcatatagtttcattttatagtttgattttatctactttgtttgtttgatattggcagttgctagatttgagcggcattctcaccgtattcttctgtggtattgtaatgtcacattacacttggcataacgtcacagagagttcaagagttacaacaaagtaaattataattctcattccatattctactgtttaatgattagcttcagttcgtagaaaaactaaacaaaacttactggtttgttttgtcctttcacctcaggcacgcatttgcaactctgtccttcattgctgagacttttctcttcctgtatgttgggatggatgcattggatattgaaaaatgggagtttgccagtgacaggtctgatacatgttctcatacctaattcctatttatggatatggagactcaattttacttctctttcccattcgcagacctggcaaatccattgggataagctcaattttgctaggattggttctgattggaagagctgcttttgtattcccgctgtcgttcttgtcgaacctaacaaagaaggcaccgaatgaaaaaataacctggagacagcaagtgagtatctggtgtatgatcagacaattttcatttgaattcgacttgccatctgctaactgaatttctctcgataggttgtaatatggtgggctgggctgatgagaggagctgtgtcgattgctcttgcttacaataaggtcagtccgtcagtgcaagactattgcttcacaccatctgtatatctgtatttctcttctcatcttgccattaattagtcccaggagaagtatgtcttagtttcttctccttaagcttaactgtctcgttgcaattgcagtttacaagatctggccatactcagctgcacggcaatgcaataatgatcaccagcaccatcactgtcgttctttttagcactatggtgagtcatcttactgcaacctatgcctaacgcaaagcgtcctcttttcatccaagtttgtgccacatgtctgaattctcaccctaaacaggacctcagcattaagctaacctaataataagttcctcaaagtcgattgtcaaatcaaaattgtcagctgtgacaaaagtaatctggaagcttgtaatgttgaacatgctctaatccaaccaaaaccaactactgaccggagaatgaaatcatgtctttttgtccctactatcttgtcctcttcttatcccttctgaagagattgccgtaccgtccagtcattgactcatcgtccatattctcacatgacatggatcaaggatggcacaattatttgaaattaattgtcgtttgttactactagcttttcgttttagttttctggatgtttctttaggaagacatacatgtgtcatcatgtcgaattgcgcatccaatcacttgattgtttacgagctaaatccttgttcagaatccctggaagctcaaatgtgcaaaacatctatttttgtgaaacatactgacatttataaatgtttattaggtatttgggatgatgacaaagccattgatcaggctgctgctaccggcctcaggccatcctgtcacctctgagccttcatcaccaaagtccctgcattctcctctcctgacaagcatgcaaggttctgacctcgagagtacaaccaacattgtgaggccttccagcctccggatgctcctcaccaagccgacccacactgtccactactactggcgcaagttcgacgacgcgctgatgcgaccgatgtttggcgggcgcgggttcgtgcccttctcccctggatcaccaaccgagcagagccatggaggaagatgaacagtgcaaagaaatgagaatggaatggttgatgaggagaatacatgtaaaatgtgacagcaaaagagagaaggcaagttttgggtttgtagagtttggctgctgctaatgagttgttgatagtgcctatattcttcagaacttcagatggtgcctcaccaaggcctaagagccaggaggaccttctgataatggttcgggatgattggtttgttctgtcaggatgaaccctagtgagtgacacagggtgatgtgctccgacaacctgtaaattttgtagattaacagccccatttgtacctgtctaccatctttagttggcgggtgttctttcctagttgccaccctgcatgtaaaatgaaattctccgccaaaatagatttgtgtgtataataattttgcttggttgatataatggtatggcatggtttgc</dnaseqindica>
External Link(s)	NCBI Gene:Os07g0666900, RefSeq:Os07g0666900