W531 Transcriptional Analysis of Dormancy and Sprout Control in Potato

Date: Tuesday, January 17, 2012
Time: 5:10 PM
Room: Royal Palm Salon 4,5,6
Michael Campbell , Penn State Erie, The Behrend College, Erie, PA
Jeffrey Suttle , United State Department of Agriculture, Agricultural Research Service, Fargo, ND
The utility of potato as a major world crop is predicated on its nutritional value as well as its ability to be stored postharvest. Short-term commercial storage of potato tubers may rely on innate tuber dormancy but maintenance of market quality during long-term storage requires the application of sprout inhibitors such as chlorpropham (CIPC) or 1,4-dimethylnaphthalene (DMN). In this study, we utilized cDNA and oligonucleotide microarrays to examine transcriptional profiles of meristems isolated from dormant, nondormant, and tubers treated with the sprout inhibitors CIPC and DMN. The transition from the dormant to nondormant state in tuber meristems was associated with a decrease in endogenous abscisic acid (ABA) content and in ABA-regulated transcripts and tuber specific genes such as patatin.  The sprout inhibitors CIPC and DMN did not result in an increase in ABA but they did result in the increase in expression of some ABA-regulated transcripts. Both sprout inhibitors resulted in transcript profiles that were significantly different from the dormant state and thus did not prevent sprout growth by maintaining or inducing dormancy. CIPC resulted in cell division arrest in the G2/M-phase of the cell cycle while DMN resulted in cell cycle arrest in the G1/S-phase based on the lack of measurable DNA synthesis. Transcriptional analysis of DMN-treated tubers indicated that there was an increase in expression of RNA encoding the cell cycle inhibitors KRP1 and KRP2 which are known to suppress cell division in the G1/S-phase. Based on these data, we conclude that the sprout inhibitors DMN and CIPC have distinct modes of action and neither prevents growth through a prolongation of the dormant state.