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Abstract Detail

Genetics Section

Gregoris, Amanda S. [1], Hall, Jocelyn C. [2], El Kayal, Walid [3], Cooke, Janice E. K. [3].

Defining Roles for SVP-like Genes in the Activity-Dormancy Transition of White Spruce Terminal Buds.

White spruce (Picea glauca) and other perennial species have the unique ability to prepare for harsh winter conditions by terminating cell proliferation at meristems to enter the dormant state, and resuming cell division the following spring. Development of the terminal bud is a precursor to dormancy induction at the shoot apical meristem, and is followed by growth cessation. Timing of bud set is an important trade-off between protecting shoot apical meristems from the damaging effects of winter frosts and wood biomass accumulation. Shortening day length (photoperiod) and lower temperatures are important for induction of bud formation and dormancy in many north-temperate forest tree species. Unlike photoperiod-dependent trees, white spruce is able to complete bud formation in the absence of dormancy inducing cues such as shortened day length. However, short days have been found to accelerate bud formation by suppressing the occurrence of second flush.
The regulatory network involved in controlling seasonal apical bud formation in perennials shares similarities with that controlling the transition of apical meristems from vegetative to flowering growth. MADS-box genes encode transcription factors that play crucial roles in plant development, including regulating the transition from vegetative to reproductive growth. The MADS-box transcription factor SHORT VEGETATIVE PHASE (SVP) inhibits flowering in Arabidopsis, and SVP-like genes have been implicated in regulating bud formation and/or dormancy in peach and kiwi fruit. Using microarray data, we have obtained white spruce MADS-box genes that may play roles in regulating processes that take place during bud formation and dormancy acquisition. Phylogenetic analysis has identified that seven white spruce SVP-like genes form a monophyletic clade with characterized SVP genes from angiosperm species, suggesting there could be some degree of conserved SVP function between angiosperms and conifers. Transcript profiling of SVP-like genes in shoot tips during the transition from active growth to bud set under short and long day conditions suggests that SVP-like genes are involved in various stages of bud formation. Preliminary in situ hybridization analysis of developing buds shows that SVP-like gene expression is localized to the apical meristem, needle primordia and procambium. We plan to conduct complementation assays with Arabidopsis thaliana svp mutants to test whether any white spruce SVP-like genes can functionally substitute for AtSVP.
Through these experiments we hope to uncover genes underlying the molecular basis of bud formation and dormancy regulation in white spruce, and demonstrate the degree of conserved function between conifer and angiosperm orthologs.

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1 - University of Alberta, Department of Biological Sciences, CW 405, Biological Sciences Bldg., University of Alberta, Edmonton, Ab, T6G 2E9 , Canada
2 - University Of Alberta, Harvard University Herbaria, CW 405 Biological Sciences Building, Edmonton, AB, T6G 2E9, Canada
3 - University of Alberta, Biological Sciences, CW 405, Biological Sciences Bldg., University of Alberta, Edmonton, AB, T6G 2E9 , Canada

Picea glauca

Presentation Type: Oral Paper:Papers for Sections
Session: 17
Location: Salon 15/16/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 1:30 PM
Number: 17001
Abstract ID:190
Candidate for Awards:Margaret Menzel Award,CSPB President's Award for Best Student Presentation

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