Isolation and Sequence Analysis of Wheat Tissue-Specific cDNAs by Differential Display

The differential display technology was used to study and isolate tissue-specific cDNA from wheat (Triticum aestivum). cDNA was synthesized by reverse transcription from total RNA from wheat leaves, anthers, and ovaries to search for and isolate tissue-specific cDNAs and use them to screen wheat genomic library to get the corresponding genomic DNA clone. Here, we report the isolation, cloning, and sequencing of various tissue-specific cDNA fragments. Further, we report the isolation of a wheat genomic clone, 18-3. The clone has an unknown open reading frame (ORF238) that is similar to related grain EST sequences, 1,673 bp 5′ flanking region from the ATG and 1321 3′ flanking region. A PlantCARE database search using the 5′ flanking region revealed that there are many cis-acting elements in this region. About 109 cis-acting elements from different plant gene promoters in 24 groups were detected. For example, 26 CAAT elements, a common cis-acting element in promoter and enhancer regions, were detected overall the 5′ flanking region. Multiple TATA-boxes concentrated in three spots and a putative transcription start site also were detected. In addition, MeJA, DRE, GC-motif, ABRE, GCN4_motif, Skn_1-motif, HSE, A-box, ACE, G-box, I-box, TCCC-motif, P-box, TATC-box, and WUN-motif were detected. The putative function of the reported ORF238 and its promoter is unknown.