The transcriptome response of leaves of the resurrection plant Xerophyta humilis to desiccation

Measurement of changes in the mRNA transcript abundance of 1709 cDNAs in Xerophyta humilis leaves at 6 relative water contents (RWC) (100%, 80%, 60%, 40%, 20% and 5%RWC respectively). 3105 cDNA clones (corresponding to 1709 unique cDNAs) were randomly selected from X. humilis cDNA libraries (Leaf Dehydration (LD), Leaf Rehydration (LR), Root Dehydration (RD) and Root Rehydration (RR)), amplified by PCR, and printed on each glass slide multiple times (ranging from 4 to 12X), such that each printed block contained a random unbiased mixture of cDNAs from the 4 different cDNA libraries. Total RNA extracted from each X. humilis leaf sample was linearly amplified, labelled with Cy3, and simultaneously hybridized with Cy5 labelled common reference RNA, to the printed cDNA arrays. The reference RNA comprised equal amounts of total RNA pooled from 6 different RWC experimental samples. Data was recorded for five biological replicates for each of the 6 RWC stages being investigated.