Plant gene expression profiling with DNA microarrays

Researchers in this age face revolutionary challenges in the pursuit of biological questions. The availability of vast amounts of genome sequence information has dramatically altered both the experimental scale and strategies for conducting research. Experimental designs allowing high through-put screening, measurement and cross-referencing will benefit the most from this treasure of sequence data. The microarray is one of the technologies permitting simultaneous interrogation of complex nucleic acid mixtures. The genome-wide examination of gene expression with this technology has provided transcript profiles of numerous biological samples. When coupled with a microarray expression database and data analysis and viewing tools, these data can serve as a foundation for proposing hypotheses and performing dedicated research. For Arabidopsis thaliana (L. Heynh.), the completion of the genome sequence offers plant biologists rich information for further understanding the growth and development of this model plant. This knowledge will have a clear impact on the strategies chosen to improve other economically important crop plants. This article reviews the DNA microarray technology and its application in the field of plant research. As an example of the kind of meta-analysis that is possible with a large public microarray expression database, we identify genes with very stable expression patterns, suitable as reference or control genes in northern blots, and genes with highly variable expression patterns in 162 Arabidopsis experiments.