thaliana, has led to the identification of many genes that are up

thaliana, has led to the identification of many genes that are up regulated protein inhibitor by CKs including members of expansin, GRPs, NAM, F box protein, ERBFs, putative ring zinc finger protein, a member of the bHLH family, blue copper binding protein and PSK2. The blue copper binding protein and putative ring zinc finger protein identified by Brenner et al. as CK induced were observed to be up regulated in our microarrays analysis. Similarly, gene expression Inhibitors,Modulators,Libraries analysis of transgenic A. thaliana seedlings transformed with bacte rial isopentenyl transferase gene revealed increased transcript abundance for many members of MAPK and WRKY gene families, which included the spe cific WRKY gene At1g80840 that has been detected in our microarray studies as being induced by ABR17 expres Inhibitors,Modulators,Libraries sion.

Another investigation into CK action in Arabidopsis has demonstrated increased expres sion of genes for cytochrome P450, PDF, expansin, pata tin, WRKY members and putative disease resistance protein in response to CKs. Therefore, it is apparent that several genes whose Inhibitors,Modulators,Libraries transcript levels were modulated by ABR17 expression in A. thaliana have been previously reported in the literature as being CK responsive, there by suggesting an important role for CK mediated gene expression in ABR17 action in planta. Second set of transcriptional profiling genes responsive to salt stress in WT A. thaliana Microarray based analyses of the salt responses in Arabi dopsis have been published in several reports. However, most of these studies Inhibitors,Modulators,Libraries have investigated responses to very short term exposure to salt.

Inhibitors,Modulators,Libraries In this study, we report the transcriptional changes in A. thaliana as a result of long term, continuous exposure to 100 mM NaCl. Here, we allowed A. thaliana seeds to germinate and grow on semi solid medium in the presence of 100 mM NaCl for 2 weeks, and the RNA extracted from whole seedlings were used for cDNA synthesis and subsequent microarray anal ysis. The results from microarray analysis of salt treated WT Arabidopsis seedlings agreed with previous studies using similar approaches. We identified 163 genes that showed more than four fold changes in transcript abundance which have been previ ously reported as being responsive to salt. Our results, therefore, indicate that both short term shock treat ments with NaCl as well as long term treatment used in this study elicit similar responses in A.

thaliana at the tran script level. Members of protease inhibitor lipid transfer protein family were seen among highly up regulated and or down regulated genes. At least five members showed increase in transcript abundance and 1 member showed decrease in transcript abundance of more than 4 fold. LTP genes contain ABA responsive element and are induced by the absci sic acid. It has been reported in the litera ture that NaCl, mannitol or ABA treatments induce the expression of a gene encoding an LTP like protein in tomato.

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