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Function Analysis Of SsNHX1,AtNHX1 And AtNHX5 Gene

Posted on:2006-03-23Degree:MasterType:Thesis
Country:ChinaCandidate:W H LiFull Text:PDF
GTID:2120360155959790Subject:Developmental Biology
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Salt stress disrupts homeostasis in ion distribution of plant cell. High levels of sodiumion (Na~+) in the cytoplasm are toxic to plants because of their adverse effects on celluarmetabolism. One important strategy for plants to improve salt tolerance is to re-establish theionic homeostasis. Ionic homeostasis involving in Na+ entry, efflux, sequestration and longdistance transport. Maintaining a low Na~+,high K~+ state is a bacis strategy for plants totolerate high soil salinity. The most direct way to maintain low cytoplasmic Na~+ is tosequester it in vacuoles within each plant cell. The importance of vacuolar sequestration toplant salinity tolerance has been underlined by experiments in which constitutiveoverexpression of vacuolar transporters has greatly increased salinity tolerance of a range ofspecies. SsNHX1 from Suaeda salsa, encodes a vacuolar Na~+/H~+ antiporter and may playimportant roles in ion homeostasis. S. salsa show high salinity tolerance. It's an ideal plant forstudying Na~+ sequestration of vacuole.In this research, SsNHX1 (1665bp), SsNHX2 (N terminus truncated forms, truncationamino acids 49), AtNHX1 (1614bp) and AtNHX5 (1554bp) were inserted into binary plantvector pROKII. The resulting plasmid were mobilized to Agrobacterium tumefaciens strainGV3101 used for plant transformation. The genes were introduced into Arabidopsis thaliana(ecotype Columbia) by Agrobaterium tumefaciens-mediated transformation withfloral-dipping method under the control of CaMV 35S promoter. Transformants were selectedfor their ability to grow on medium containing kanamycin (40mg/L). Several homozygouslines transformed with SsNHX1 and SsNHX2 were selected and used for further molecular andphysiological determination. Whether the genes was transformed into the Arabidopsis wasconfirmed by Southern blotting and Northern blotting. We only selected T1 transformants ofAtNHX1 and AtNHX5 in this research because we had no enough time and energy.Molecular and physiological determination result of SsNHX1 and SsNHX2 homozygous...
Keywords/Search Tags:halophyte, SsNHX1, SsNHX2, AtNHX1, AtNHX5 gene, N terminus truncation, vacuolar Na~+/H~+ antiporter, salt tolerance, Arabidopsis thaliana
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