35th NPS abstract book

Transcriptional networks regulating tension wood
formation in Populus
S3.4
MATTHEW ZINKGRAF 1,2,4 , ANDREW GROOVER 2 , 14:00–14.30
SUZANNE GERTTULA 2 , SHAWN D. MANSFIELD 3 and
VLADIMIR FILKOV 4
mszinkgraf@fs.fed.us
1 Postdoctoral Research Fellow in Biology, National Science Foundation;
2 Pacific Southwest Research Station, Forest Service, Davis CA USA;
3 Department of Wood Science, University of British Columbia, Vancouver
BC Canada; 4 Computer Science Department, University of California –
Davis, Davis CA USA
Angiosperm trees respond to gravitational and mechanical stresses by producing tension wood,
which generates the tensile force necessary to reorient and reinforce woody stems. In this talk, we
present results from Populus tension wood experiments that integrate data from genome-wide gene
expression and transcription factor binding experiments with physiological and biochemical data.
Treatments included perturbation of ARBORKNOX2 expression and treatment with gibberellic acid.
Modules of genes were defined based on co-expression patterns across wood types, genotypes, and
gibberellic acid treatments. Modules were then tested for correlations with wood types, genotypes,
GA treatment, and various measures of wood chemistry attributes. Modules were identified that
have significant correlations with phenotypes, and enrichment for ARK2 binding. Modules were also
characterized by GO analysis, and modules were further annotated based on enrichment with key
processes that contribute to cambium function, secondary cell wall biosynthesis and hormone
regulation. We further show how these gene modules can be further dissected to identify candidate
regulatory genes responsible for control of specific traits. Together, these results present an
integrated view of the key changes in gene expression and transcription factor binding that influence
tension wood development and generation of the forces underlying the reorientation of woody
stems, and provide results and methods that can be applied for complex trait dissection in trees.
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