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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Sugarbeet and Potato Research » Research » Publications at this Location » Publication #303011

Title: Treatment of potato tubers with the synthetic cytokinin 1-(alpha-ethylbenzyl)-3-nitroguanidine results in rapid termination of endodormancy and induction of transcripts associated with cell proliferation and growth

item CAMPBELL, MICHAEL - Pennsylvania State University
item Suttle, Jeffrey
item DOUCHES, DAVID - Michigan State University
item BUELL, C - Michigan State University

Submitted to: Functional and Integrative Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/13/2014
Publication Date: 12/1/2014
Citation: Campbell, M., Suttle, J.C., Douches, D.S., Buell, C.R. 2014. Treatment of potato tubers with the synthetic cytokinin 1-(alpha-ethylbenzyl)-3-nitroguanidine results in rapid termination of endodormancy and induction of transcripts associated with cell proliferation and growth. Functional and Integrative Genomics. 14:789-799.

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. Because of this, sprouting results in severe financial loss to producers. In other situations requiring the rapid replanting of potatoes immediately after harvest, the deliberate stimulation of premature sprouting would be highly beneficial. The research being conducted in this project is directed towards: 1.) identifying key physiological processes that naturally regulate tuber dormancy and, ultimately, 2.) modifying these processes genetically thereby eliminating the need for artificial sprout suppression. Previous research from this laboratory has demonstrated that treatment of dormant tubers with either naturally occurring or synthetic cytokinins results in premature sprouting and the synthetic cytokinin 1-(a-ethylbenzyl)-3-nitroguanidine (NG) is one of the most effective dormancy breaking agents yet identified. However, the mechanisms by which NG treatment induces dormancy exit are unknown. In this paper, the effects of NG treatment on gene expression in tuber eyes are compared to those occurring during natural dormancy exit using the powerful technique of RNA-seq. These studies demonstrated that nearly identical changes in the expression of key genes linked to growth occur in both NG treated eyes and eyes naturally exiting dormancy following extended storage. These results suggest that NG treatment may be useful in situations where premature sprouting is desirable such as in the seed potato industry.

Technical Abstract: Perennial plants undergo repression of meristematic activity in a process called dormancy. Dormancy is a complex metabolic process with implications for plant breeding and crop yield. Endodormancy, a specific subclass of dormancy, originates within tissue which is in a repressed state of growth and often involves apical and lateral meristems. In this study, we examine transcriptional changes associated with the natural cessation of endodormancy in potato tuber meristems and in endodormant tubers treated with the cytokinin analog 1-(a-ethylbenzyl)-3-niroguanidine (NG), which terminates dormancy. RNA-sequencing was used to examine transcriptome changes between endodormant and non-dormant meristems from four different harvest years. A total of 35,091 transcripts were detected with 2132 differentially expressed between endodormant and nondormant tuber meristems. Endodormant potato tubers were treated with the synthetic cytokinin NG and transcriptome changes analyzed using RNA-seq after one, four, and seven days following NG exposure. Comparison of NG-induced and natural cessation of dormancy demonstrated that by four days after NG exposure, potato meristems exhibited transcriptional profiles similar to the nondormant state with elevated expression of multiple histones, a variety of cyclins, and number of genes associated with proliferation and cellular replication. Three homologs encoding for CYCD3 exhibited elevated expression in both non-dormant and NG treated potato tissues. These results suggest that NG terminates dormancy and induces expression cell cycle associated transcripts within four days of treatment.