The plant cell wall is composed primarily of a polysaccharide network consisting of cellulose, hemicelluloses, and pectin. Cellulose microfibrils are the main component of the cell wall. They are composed of clusters of hydrogen-bonded chains of β-1, 4- glucans. At present, it is not understood how the integrity or mechanical differences in the plant cell wall are perceived, nor is it known how signalling pathways, leading to either stress responses or compensatory adjustments, are regulated. Since there is no precedence on which to base predictions about gene function with respect to cell wall synthesis, assembly or integrity, genetic analysis provides an unbiased way of identifying important gene products involved in these processes. Gene expression profiling is one way to study relevant genetic circuits that control cell wall assembly and integrity. The difficulty associated with monitoring these circuits has been the ability to modulate cell wall integrity in a reliable, short-lived way. However, by virtue of their effects on cellulose content, CBIs, a number of cellulose biosynthesis inhibitors, provide an excellent way to achieve this type of manipulation. We have therefore initiated a project aimed at querying a number of structurally unrelated CBIs by using RNA from plants that were treated with different CBIs to probe Affymetrix Arabidopsis microarrays.