Transcriptional profiling of chickpea genes differentially expressed in response to drought stress using high density oligonucleotide microarray

Chickpea (Cicer arietinum L.) is an important pulse crop grown mainly in the arid and semi-arid regions. Due to its taxonomic proximity with the model legume Medicago truncatula and its ability to grow in arid soil, chickpea has its unique advantage to understand how plant responds to drought stress. This microarray was used for analyze the transcriptomic profiles of unigenes in leaf and root of chickpea seedling under drought stress, respectively. Microarray data showed that 4805 differentially expressed unigenes were either greater than 2 fold up- or less than 0.5 fold down-regulated in at least one of the 5 time points during drought stress. 2003 and 3488 unigenes were time-dependent differentially expressed in root and leaf, respectively. 110 pathways in two tissues were found to respond to drought stress. Compared to control, 88 and 52 unigenes were expressed only in drought-stressed root and leaf, respectively, while nine genes were expressed in both tissues. 2484 function-unknown unigenes were found to be remarkably regulated by drought stress. The expression profiles of these time-dependent differentially expressed unigenes were useful in furthering our knowledge of the drought tolerance mechanism of plant. Total RNA from the control root and leaf and drought-stressed root and leaf of chickpea were used to generate target cDNA, and then hybridized to Agilent Chickpea Gene Expression Microarray representing about 6000 unigenes.