Exposure of Potato Tuber to Varying Concentrations of 1,4-Dimethylnaphthalene Decrease the Expression of Transcripts for Plastid Proteins

Application of the compound 1,4-dimethylnaphthalene (DMN) has been found to reduce premature sprouting in stored potato tubers. The mechanism of action for DMN has yet to be elucidated but transcriptional changes are known to occur following exposure. In this study non-dormant potato tubers (Solanum tuberosum L., cv. Russet Burbank) were treated with varying amounts of DMN resulting in an increasing residue on the tuber surface. RNA sequencing was used to measure transcriptome changes in excised meristems from tubers having increasing DMN exposure. Treatment of tubers with DMN that resulted in surface residue levels greater than 2 ppm was associated with a decrease in 45 transcripts that encoded for proteins linked with plastid development and function and an increase in the expression of 15 transcripts that encoded for WRKY-type transcription factors. qt-PCR analysis showed that repression of plastid transcripts appeared to recover 7 days after DMN exposure but induction of WRKY transcripts was maintained up to 35 days post treatment. The data suggests DMN may inhibit plastid development short term but also results in long-term changes in some regions of the transcriptome.