PHYTOHORMONE AFFECTS ATHKT1 EXPRESSION AND Na ACCUMULATION IN Arabidopsis thaliana
abstract:
AtHKT1 which is expressed in the plasma membrane of parenchyma cells, recirculates Na from shoot to root system, leading to the detoxification of Na in Arabidopsis thaliana during salt stress condition. This article reports the effect of phytohormone on the expression of AtHKT1 in relation with Na accumulation in root and shoot of Arabidopsis thaliana. GUS expression was detected in the Arabidopsis plants bearing AtHKT1 promotor-GUS fusion grown in ½ strength MS media supplied with 0.5 µM of water (control), IAA, NAA, GA3, BAP, Kinetin, Zeatin, Methyl Jasmonate or Brassinolide for one week. Na content in shoot and root of wild type, mutant and over-expressed AtHKT1 plants grown in 0 or 75 mM NaCl with or without 0.5 µM NAA or GA3, was measured. The results shown that the expression of AtHKT1 gene in Arabidopsis thaliana was strongly induced by NAA and GA3. Since Na content in the shoot of mutant was much higher than those of wild type and over-expressed AtHKT1-plants, then this indicates that AtHKT1 plays an important role on removing Na from shoot to root, leading to plant salt adaptation. This mechanism is stimulated by NAA and GA3, which strongly induce the expression of AtHKT1 gene.
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