The sprout inhibitor 1,4-dimethylnaphthalene induces the expression of the cell cycle inhibitors KRP1 and KRP2 in potatoes

Abstract The suppression of sprout growth is critical for the long-term storage of potato tubers. 1,4-Dimethylenapthlene (DMN) is a new class of sprout control agent but the metabolic mode of action for this compound has yet to be elucidated. Changes in transcriptional profiles of meristems isolated from potato tubers treated with the DMN were investigated using an Agilent 44 K 60-meroligo microarray. RNA was isolated from nondormant Russet Burbank meristems isolated from tubers treated with DMN for 3 days or activated charcoal as a control. RNA was used to develop probes that were hybridized against a microarray developed by the Potato Oligo Chip Initiative. Analysis of the array data was conducted in two stages: total array data was examined using a linear model and the software Limma and pathway analysis was conducted by linking the potato sequences to the Arabidopsis thaliana. DMN elicited a change in a number of transcripts associated with cold responses, water regulation, salt stress, and osmotic adjustment. DMN also resulted in a repression of cyclin or cyclin-like transcripts. DMN also resulted in a 50% decrease in thymidine incorporation suggesting a repression of the S phase of the cell cycle. Quantitative real-time polymerase chain reaction analysis demonstrated that DMN increased transcripts for the cell cycle inhibitors KRP1 and KRP2. We conclude the DMN results in alteration of genes associated with the maintenance of a G1/S phase block possibly through the induction of the cell cycle inhibitors KRP1 and KRP2.