Using DDRT-PCR technique to identify salt-induced transcripts from the halophytic plant Cakile maritima

Sea-rocket (Cakile maritima) is a halophytic plant that possess many unique genetic characteristics contributing to plant's ability to withstand and tolerate salinity conditions. It is a member of the Brassicaceae family, with a small genome size (approximate to 720 Mb) and a short life cycle, making it of value for conducting genetic studies to understand molecular bases of salinity. In the present work, we exposed C. maritima seedlings to different salt treatments in combination with different exposure time to identify new salinity-responsive genes. One group was directly treated with different salinity levels (0, 100, 200, 300 and 400 mM NaCl2) for 4, 8, and 12 hrs.; while the second group was subjected to a gradual increase of salt concentration. Some of the transcripts that differentially expressed in response to the salinity stress were isolated using the differential-display reverse transcription-PCR (DDRT-PCR) technique. Fourteen re-amplified fragments were selected, and were bioinformatically analyzed and annotated. The genes were categorized according to their proposed function into two major categories, the first group of genes contains those that were related to cellular membranes stabilization {Rho GTPase-activating protein, beta-galactosidase gene, Arabinogalactan (AGP) genes, and ATP-Binding Cassette transporter (ABC transporter) C family member 10). The second group of genes include genes involved in pathways directly or indirectly involved in stabilizing cells under salinity stress {receptor 3 from Toll-like protein (TLR3), 4 fragments homologues to different Alcohol dehydrogenase (ADH), Polybromo protein, 3-hydroxyisobutyryl-CoA hydrolase gene, MOR1 gene and 2 fragments homologue to sulfite reductase (SiR) gene}.