Other genes which exhibited increase in transcript abundance of more than 2 fold in salt treated ABR17 transgenic but showed less abundance in treated WT included pathogenesis related protein, and glutamine dependent asparagine synthetase. On the other hand, the retroelement pol polyprotein with unknown function showed a down regulation of more than 2 fold neither in Inhibitors,Modulators,Libraries salt treated transgenic ABR17 line, but was up regulated in salt treated WT Arabidopsis plants. Interestingly, many members of heat shock protein family and PDF family showed the opposite response in salt treated ABR17 transgenic seedlings compared to the salt treated WT counterparts, with an increase of transcript abundance in salt treated ABR17 transgenic. This difference in the direction of the response in gene expression i. e.

induction in the transgenic seedlings versus the repression in the WT may have important Inhibitors,Modulators,Libraries conse quences with respect to the ability to tolerate salinity stress. For example, Inhibitors,Modulators,Libraries the Hsp family con tains chaperones, which have important roles in protein folding, assembly and in the disposal of unwanted non functional proteins. Hsps are usually induced by environ mental stress, and the accumulation of Hsps coincides with enhanced stress tolerance. In addition, transgenic Arabidopsis plants overexpressing AtHSP17. 7 accumulate high levels of AtHSP17. 7 protein and show enhanced tolerance to drought and salinity. The abundance of Hsps in plants and their functional charac teristics suggest that Hsps play an important role in plant stress tolerance.

Thus, the increased abundance of HSP transcripts in the ABR17 transgenic seedlings may be important for the increased tolerance Inhibitors,Modulators,Libraries of this line to the imposed Inhibitors,Modulators,Libraries stress. The up regulation of PDFs in ABR17 transgenic A. thaliana grown under normal conditions and their importance in growth and development has already been discussed earlier. The literature also supports a role for PDFs in stress tolerance. Most of the previously characterized PDFs exhibit anti fungal, antibacterial, anti insect and protease inhibitor activity. However, the halophyte salt cress, a relative of Arabidopsis over expresses PDFs under normal conditions and hence defensins are believed to play a role in salt tol erance. It is therefore possible that the observed rela tively tolerant phenotype of ABR17 transgenic seedlings could be due, at least in part, to the elevated expression of XTR6, RAP2.

6 transcription factors, unknown proteins, Hsp and PDF gene. Addi tional studies are underway in our laboratory to precisely characterize the role of the above mentioned genes in stress tolerance www.selleckchem.com/products/Calcitriol-(Rocaltrol).html of ABR17 transgenic A. thaliana seedlings. qRT PCR validation of microarray observations In order to confirm the fact that CK responsive genes were indeed up regulated in the ABR17 transgenic lines, we performed qRT PCR experiments with the following genes plant defensin protein using qRT PCR.