Submitted to: Functional and Integrative Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/31/2008
Publication Date: 5/1/2008
Citation: Campbell, M.A., Segear, E., Beers, L., Knauber, D.C., Suttle, J.C. 2008. Dormancy in potato tuber meristems: chemically induced cessation in dormancy matches the natural process based on transcript profiles. Functional and Integrative Genomics. 8:317-328. doi:10.1007/s10142-008-0079-6. Interpretive Summary: For an indeterminate period of time following harvest, potatoes will not sprout and are physiologically dormant. Dormancy is gradually lost during postharvest storage and the resultant sprouting is detrimental to the nutritional and processing qualities of potatoes destined for human consumption. However for seed potatoes, lengthy dormancy is a disadvantage and can result in poor plant stands and reduced yields. The research being conducted in this lab is directed towards 1.) identifying key physiological processes that naturally regulate tuber dormancy and, ultimately, 2.) manipulating these processes to suit the needs of producers of table, process, and seed potatoes. Although it is widely assumed that wholesale changes in gene expression accompany (and may control) the transition between dormancy-imposed growth arrest and sprouting, there have been no studies that directly examine this process in tuber buds. In this paper, changes in gene expression were determined in tuber buds isolated from dormant tissues and in tissues that exited dormancy naturally or after artificial manipulation. Only a limited number of genes demonstrated significant changes in expression during dormancy exit and many of the same genes were expressed under both dormancy-ending conditions suggesting that they may play important roles in the regulation of bud growth. These studies demonstrated that dormancy progression does not require massive reprogramming of gene expression and that only a few genes may control this transition.
Technical Abstract: Meristem dormancy in perennial plants is a developmental process that results in repression of metabolism and growth. The cessation of dormancy results in rapid growth and should be associated the production of nascent transcripts that encode for gene products controlling for cell division and growth. Dormancy cessation was allowed to progress normally or was chemically induced using bromoethane (BE) and microarray analysis was used to demonstrate changes in specific transcripts in response to dormancy cessation prior to a significant increase in growth. Comparison of normal dormancy cessation to BE-induced dormancy cessation revealed a commonality in both up and down regulated transcripts. Many transcripts that decrease as dormancy terminates are inducible by abscisic acid particularly in the conserved BURP domain proteins, which include the RD22 class of proteins and in the storage protein patatin. Transcripts that are associated with an increase in expression encoded for proteins in the oxoglutarate dependent oxygenase family. We conclude that BE induced cessation of dormancy initiates transcript profiles similar to the natural processes that control dormancy.