Digital gene expression (DGE) of alkali-stressed cucumber leaves

Here we performed a transcriptomic study on the effect of sodium nitroprusside (SNP) on cucumber leaves under alkali stress using Solexa/Illumina's high-throughput digital gene expression (DGE) system. Two DGE libraries (from one NaHCO3-treated sample and one NaHCO3 + SNP-treated sample) were constructed, and the gene expression variations between the two samples were compared. Hundreds of differentially expressed genes were obtained by the comparison, and GO analysis of these genes suggested that many biological processes, molecular function, cellular components were related to SNP’s mitigated effect on alkaline stress. The authenticity of the DGE data was further confirmed by analyzing real-time RT-PCR using several random-selected genes. The experiment had 2 treatments: 30 mM NaHCO3 (alkali stress treatment, indicated as Na) and 30 mM NaHCO3+100 μM sodium nitroprusside (indicated as SNP). Samples from Na- and SNP-treated leaves, used for RNA isolation, were harvested, and the two corresponding tag libraries of samples were constructed in parallel. Illumina sequencing of transcripts from Na- and SNP-treated samples to get gene information for cucumber leaves in different treatments.