Gene differential expression of Kosteletzkya virginica（L.） Presl seedling under salt stress in roots and leaves was analyzed using the cDNA-amplified fragment length polymorphism（cDNA-AFLP） technique.Polymorphic transcript-derived fragments（TDFs） between the control plants and salt-treated plants were grouped into four main differential expression patterns: repression

de novo induction

up-regulation

and down-regulation.Among them

34 differentially expressed gene fragments were homologous to the known genes from other species and 4 were new sequences with unknown functions.These differentially expressed genes of K.virginica seedlings under salt stress can be classified into four groups according to their putative functions.The changes of six differentially expressed genes were selected and confirmed by quantitative real-time RT-PCR.The transcription of Avp1

Nhx1 and Oat is up-regulated in roots and leaves.mRNAs of Gapdh and Pmp in leaves are up-regulated while down-regulated in roots.The transcription of Chx1 is up-regulated in roots while down-regulated in leaves.From the above results

it is speculated that salt tolerance in K.virginica seedlings is related with limiting Na+ level in leaves and accumulating Na+ in roots.