Search

Full‐length cDNAs are essential for the correct annotation of genomic sequences and for the functional analysis of genes and their products. 155 144 RIKEN Arabidopsis full‐length (RAFL) cDNA clones were isolated. The 3′‐end expressed sequence tags (ESTs) of all 155 144 RAFL cDNAs were clustered into 14 668 non‐redundant cDNA groups, about 60% of predicted genes. The sequence database of the RAFL cDNAs is useful for promoter analysis and the correct annotation of predicted transcription units and gene products. Recently, cDNA microarray analysis has been developed for quantitative analysis of global and simultaneous analysis of expression profiles. RAFL cDNA microarrays were prepared, containing independent full‐length cDNA groups for analysing the expression profiles of genes under various stress‐ and hormone‐treatment conditions and in various mutants and transgenic plants. In this review, recent progress on transcriptome analysis using the RAFL cDNA microarray is highlighted. [ABSTRACT FROM PUBLISHER]

The hypersensitive response (HR) was induced in a wild-type Arabidopsis thaliana plant (Columbia) (Col-wt) by inoculation with Alternaria brassicicola that causes the development of small brown necrotic lesions on the leaves. By contrast, pad3-1 mutants challenged with A. brassicicola produced spreading lesions. The cell death in pad3-1 mutants could not inhibit the pathogen growth and development, although both production of H2O2 and localized cell death were similar in Col-wt and pad3-1 plants after the inoculation. The difference between Col-wt and pad3-1 plants is defense responses after the occurrence of cell death. In other words, PAD3 is necessary for defense response to A. brassicicola. Therefore, we examined the changes in the expression patterns of ca. 7,000 genes by cDNA microarray analysis after inoculation with A. brassicicola. The cDNA microarrays were also done to analyze Arabidopsis responses after treatment with signal molecules, reactive oxygen species (ROS)-inducing compounds and UV-C. The results suggested that the pad3-1 mutation altered not only the accumulation of camalexin but also the timing of expression of many defense-related genes in response to the challenge with A. brassicicola. Furthermore, the plants integrate two or more signals that act together for promoting the induction of multiple defense pathways. [ABSTRACT FROM AUTHOR]

Summary Full-length cDNAs are essential for functional analysis of plant genes in the post-sequencing era of the Arabidopsis genome. Recently, cDNA microarray analysis has been developed for quantitative analysis of global and simultaneous analysis of expression profiles. We have prepared a full-length cDNA microarray containing ≈7000 independent, full-length cDNA groups to analyse the expression profiles of genes under drought, cold (low temperature) and high-salinity stress conditions over time. The transcripts of 53, 277 and 194 genes increased after cold, drought and high-salinity treatments, respectively, more than fivefold compared with the control genes. We also identified many highly drought‐, cold‐ or high-salinity‐ stress‐inducible genes. However, we observed strong relationships in the expression of these stress-responsive genes based on Venn diagram analysis, and found 22 stress-inducible genes that responded to all three stresses. Several gene groups showing different expression profiles were identified by analysis of their expression patterns during stress-responsive gene induction. The cold-inducible genes were classified into at least two gene groups from their expression profiles. DREB1A was included in a group whose expression peaked at 2 h after cold treatment. Among the drought, cold or high-salinity stress-inducible genes identified, we found 40 transcription factor genes (corresponding to ≈11% of all stress-inducible genes identified), suggesting that various transcriptional regulatory mechanisms function in the drought, cold or high-salinity stress signal transduction pathways. [ABSTRACT FROM AUTHOR]