BioProject

Arabidopsis thaliana plants (ecotype Landsberg erecta) were grown at 20°C constant temperature, 8 hr/16 hr Light/Dark photoperiod at 50-60% ambient humidity, for 8 to 9 weeks. More...

Arabidopsis thaliana plants (ecotype Landsberg erecta) were grown at 20°C constant temperature, 8 hr/16 hr Light/Dark photoperiod at 50-60% ambient humidity, for 8 to 9 weeks. Short day conditions prevented the onset of flowering and the plants were thus maintained in growth stage 1 (leaf production) with 13 to 15 rosette leaves larger than 1mm (stage 1.13 to 1.14). Diamondback moth (DBM, Plutella xylostella) larvae were maintained on cabbage (Brassica oleracea) plants in a climate-controlled room at 25ºC, 12 hr photoperiod with 50%-60% relative humidity. Two days before exposing A. thaliana plants to herbivore treatment, plants were transferred to a climate-controlled room (22ºC, 50-60% humidity, 12 hr photoperiod). For insect treatment, seven Diamondback moth (DBM, Plutella xylostella) larvae (third to fifth instars) were placed on a group of four or five plants until time of harvest, for each time point separately. All rosette leaves were harvested at 1h, 4h, 12h, and 24h after onset of continuous herbivory and flash frozen in liquid nitrogen. Control plants were maintained under the same conditions and harvested in parallel. Keywords: time course, stress response, herbivory response Overall design: For each time point (1h, 4h, 12h, and 24h) two biological replicates (DBM treatment) were performed. Control plants were harvested in parallel. Total RNA from each sample was used for two labelling reactions using dye-flips (Cy5 or Cy3) and labelled cDNA from treatment and control plants were co-hybridized. Thus, for each time-point four replicates were analyzed each comparing treatment with the corresponding control (rep1 and rep2 are dye-flips of biological replicate 1, and rep3 and rep4 are dye-flips of biological replicate 2). For background correction, we defined the mean of the lowest 10% of spot intensities from a particular subgrid as the background for that subgrid. This mean was subtracted from each spot in the subgrid. Signal intensities that did not exceed the background plus 3 standard deviations thereof were defined as not detectable and were excluded from further analyses. We normalized using loess curves thus generating log2 transformed expression ratios comparing DBM treatment with control. These ratios are given in the VALUE columns of each array. Less...