ID1667_P4_F1_C_F0_T2_S12_p
Three leaves from each of 3 plants grown in the following experimental conditions were sampled and analyzed for F0 and F1 generation: 2.5 M Cr (T1 (1 week) and T2 (3 weeks)); 5 M Cr (T1 and T2), control (T1 and T2).  Seeds of A. thaliana cv Col-0 were sown on peat Jyffy discs and kept in the dark at room temperature for three days. When plants reached 2 cm of total length, they were transferred in soil for 15 days and then in hydroponic culture (one plant per 500-mL pot containing Hoagland solution, (Hoagland & Arnon, 1950)) in a growth chamber (25C for 16 hours of light at 120 mol m-2s-1 and 22C for 8 hours of dark, 60% of relative humidity). Plants were maintained one week in acclimation before the application of the stress. Chromium treatments (Cr(VI) supplied as K2Cr2O7) were the following: 1) 2.5 M Cr (VI) until harvest after nine weeks of growth (chronic stress) and 5 M Cr (VI) for three weeks and then recovering in Cr-free Hoagland solution until harvest. Five plants (biological replicates) were used for each of these stress conditions in addition to five control plants (grown in Hoagland in absence of Cr stress).  Leaves were immediately frozen in liquid nitrogen and stored at -80 C. RNA extraction was performed using 100 mg of leaves grounded with mortar and pestle in liquid nitrogen. The protocol of RNeasy Plant Mini kit (Qiagen) was followed and final elutions were performed using 50 l of RNase-free water.  Eighteen sequencing libraries were obtained following the procedure of Truseq Stranded mRNA Library Prep (Illumina) and using Truseq RNA Single Indexes.