Microarray analysis of exogenous NAD+-induced transcriptome changes in Arabidopsis thaliana

The goal of the microarray was to investigate the transcriptome changes induced by exogenous NAD+ in the wild-type Col-0 plants. Results showed that exogenous NAD+-induced dramatic transcriptional changes in Arabidopsis. Particularly, a large group of salicylic acid pathway genes including NPR1 and its traget genes were induced by NAD+, whereas the jasmonic acid/ethylene pathway defense marker gene PDF1.2 was inhibited by NAD+ treatment. In addition, a group of the pathogen-associated molecular pattern pathway genes were also induced by exogenous NAD+. These results indicate that exogenous NAD+ induces defense pathways against (hemi)biotrophic pathogens but suppresses defense against necrotrophs. Two to three replicates with leaves from 8-12 plants per sample were collected at 0, 4, and 24 hr after NAD+ treatment. Leaf tissues were collected as the control at 0 hr, and NAD+-treated leaf tissues were collected at 4 and 24 hr. After extraction, RNA concentration was determined on a NanoDrop Spectrophotometer (Thermofisher Scientific, Waltham, MA) and sample quality was assessed using the 2100 Bioanalyzer (Agilent Technologies, Santa Clara, CA). Equal amount of RNA from the biological replicates were used for microarray analysis.