Sodium (Na + ) is toxic to most plants, but the molecular mechanisms of plant Na + uptake and distribution remain largely unknown. Here we analyze Arabidopsis lines disrupted in the Na + transporter AtHKT1. AtHKT1 is expressed in the root stele and leaf vasculature. athkt1 null plants exhibit lower root Na + levels and are more salt resistant than wild-type in short-term root growth assays. In shoot tissues, however, athkt1 disruption produces higher Na + levels, and athkt1 and athkt1/ sos3 shoots are Na + -hypersensitive in long-term growth assays. Thus wild-type AtHKT1 controls root/shoot Na + distribution and counteracts salt stress in leaves by reducing leaf Na + accumulation. ß 2002 Published by Elsevier Science B.V. on behalf of the Federation of European Biochemical Societies.

Excessive low-affinity Na؉ uptake is toxic to the growth of glycophytic plants. Recently

This is the first report where the blaNDM gene insertion in a plasmid is not accompanied by other resistance gene determinants. These observations suggest that the IncX3 plasmid pNDM-MGR194 is an early stage in the dissemination of the blaNDM .

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