Effect of iodine on Arabidopsis thaliana (Col-0) trancriptome

Iodine treatments specifically regulated the expression of several genes in shoot and root tissues, mostly involved in the plant defence response, suggesting the protective role of iodine against both biotic and abiotic stresses. Each sample consisted of a pool of rosettes (leaves) or roots, sampled from three different plants. Analysis was performed on 3-week-old Arabidopsis plants hydroponically grown. To identify genes whose expression was specifically altered by iodine, Arabidopsis plants were treated by adding 10 µM of NaI, KI or KBr to the basal nutrient solution, compared to the untreated control plants (iodine concentration in the basal nutrient solution was 8 nM, as a contaminant). To identify genes whose expression was specifically altered by iodine, we searched the microarray dataset for genes that responded to KI and NaI, but not to KBr. Plant material was collected 48 h after the beginning of the treatment. Plants were grown 22 °C day/18 °C night with a 12-h photoperiod, a quantum irradiance of 100 μmol photons m-2 sec-1 and a relative humidity close to 35%.