|HOWE, GLENN - Oregon State University|
|DHARMAWARDHANA, PALITHA - Oregon State University|
|PRIEST, HENRY - Danforth Plant Science Center|
|MOCKLER, TODD - Danforth Plant Science Center|
|STRAUSS, STEVE - Oregon State University|
Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/29/2015
Publication Date: 12/17/2015
Citation: Howe, G.T., Horvath, D.P., Dharmawardhana, P., Priest, H.D., Mockler, T.C., Strauss, S.H. 2015. Extensive transcriptome changes during natural onset and release of vegetative bud dormancy in Populus. Frontiers in Plant Science. 6:989. https://doi.org/10.3389/fpls.2015.00989.
Interpretive Summary: Bud dormancy is key to winter survival of many perennial trees and fruit crops as well as to many valuable herbaceous horticultural species. Understanding how and why buds go dormant will impact our ability to develop new methods to protect our fruit and forest production from global climate change. Using poplar as a model to study this phenomenon, we have examined over 30,000 genes from poplar to see which ones are turned on and off in the vegetative buds as they transition from summer to fall and then into winter and spring. Because the function of many of the genes are known, we were able to make conclusions about some the plant hormones and other physiological processes that control how the buds responded to the changing season and which controlled the characteristic types of bud dormancy. We determined that the plant hormones salicylic acid and auxin seem to have the greatest role in controlling bud dormancy, and a surprising and novel potential role for a chemical known as phenylpropanoids that are well known to help protect plants from environmental stress such as high light intensities, cold, and attack from pathogens. We also found additional evidence that the genes that control flowering in many plants also seem to have an additional role in controlling bud dormancy.
Technical Abstract: To survive winter conditions, axillary buds of poplar transition from paradormancy to endodormancy. Following sufficient chilling, endodormant axillary buds will transition from endodormancy to ecodormancy. We utilized the near whole genome NimbleGen poplar microarrays to follow transcriptome differences in axillary poplar buds through these transitions. Gene set analysis and sub-network enrichment identified physiological processes and regulatory elements associated with these transitions. Results identified differences in expression of genes associated with signaling and responses to salicylic acid, auxin, brassinosteroids, abscisic acid, and ethylene. Additionally specific transcription factors associated with the endodormancy state included several basic helix-loop-helix, MYB, and WKRY transcription factors. Promoter analysis from members of several sub-clusters of coordinately regulated genes identified numerous potential cis-acting elements that could potentially serve as binding sites for CBF and circadian-associated transcription factors involved in dormancy transitions. Combined, the data suggests complex and overlapping processes and signals play a role in dormancy transitions in poplar.