Gene expression differences under freezing and ice encasement stress in between temporal populations
Gene expression differences under freezing and ice encasement stress in between temporal populations
Plants from all temporal seedlots of Engmo and Norneg were cold acclimated under ambient light conditions, first for 6 weeks at 9°C, followed by 2 weeks at 6°C and finally 2 weeks at 2°C under 12h light ( 55 PPFD). Freezing stress samples were transfered to freezers the temperature was lowered from 2°C to -3°C by 1°C h−1 and were kept at -3°C for ~ 12 hrs to avoid supercooling. After that the temperatures  were lowered by 1°C h−1 from -3°C to -10°C and by 3°C until the pre-set temperatures were reached, i.e. -12, -15, -18, -21, -24, -27°C. batches of samples were taken at the predetermined temperatures flash-frozen for RNA extraction. The ice encasement samples were placed in a polyethyene container and filled with ice and cold water and kept in freezing rooms and batches of plants were withdrawn at 22,36, 54, 68, 75 and 82 days. The sampled plant material from freezing and ice encasement tests were crushed with mortar and pistel and the ground plant material is used for RNA extraction does not apply RNA extraction was carried out using Qiagen RNeasy Plant Mini kit according to manufacturar guidelines The libraries were prepared according to the TruSeq RNA Sample Prep Kit v2 (Illumina, San Diego, CA, USA)