Olive (Olea europaea) cv.Kalamon: Control vs Salt-treated

A transcriptomics approach was used as a tool to unravel gene regulatory network underlying salinity response in a salt-tolerant olive cultivar (cv. Kalamon) by simulating as much as possible olive growing conditions in the field. A 135 day long salinity experiment was conducted using one year old trees exposed to NaCl stress for 90 days followed by 45 days of post-stress period. Total RNA was extracted from the root samples after 15, 45 and 90 days of NaCl-treated and un-treated olive trees as well as after 15 and 45 days of post-treatment period and used for microarray hybridizations using a loop design. Hierarchical clustering of differentially expressed transcripts revealed two major, distinct clusters. Despite the limited number of probe set, a transcriptional regulatory networks was constructed for the salt-tolerant cultivar. Five experimental time-points were analyzed: 15days stress, 45days stress, 90days stress, 15days post-stress and 45days post-stress. In each timepoint treated and untreated (control) samples were obtained. Dye swap hybridizations and 4 biological replicates were performed for each treatment/timepoint in a loop design experimental setup. Low-quality arrays were not included in the data analysis (36 arrays/samples submitted). Each sample included three spot replicates.