SAGE (SERIAL ANALYSIS OF GENE EXPRESSION) OF RICE SEEDLINGS IN RESPONSE TO ANAEROBIC STRESS

Iwate Biotechnology Research Center, Kitakami, Iwate 024-0003, Japan

Serial analysis of gene expression (SAGE), developed by Velculescu et al. (1995), allows a highly accurate, quantitative analysis of expression of thousands of genes at a time, and enables us to understand function of numerous genes. As the material for the first application of SAGE to rice (Oryza sativa L.), we used 5-days-old etiolated seedlings, and their transcripts were quantitatively profiled. A total of 10122 tags (13bp fragments derived from cDNA) were obtained, among which 5921 were unique. These different tags were defined as different genes, and among them, only 1368 genes (23.1%) matched the rice cDNA or EST sequences in the DNA database. The most abundantly expressed gene in rice seedlings was a type-2 metallothionein (MT) gene, and other three MT-like protein genes were also found among the most abundant 30 genes. Gene expression profiles were compared between anaerobically-treated and non-treated rice seedlings using SAGE technique. Analysis of about 5000 tags showed that several genes are differentially expressed in response to anaerobic stress. Some of these genes are not previously described as anaerobically inducible genes.