35th NPS abstract book

P23
Sequence characterization of a CONSTANS-like gene in North American red
oaks
J. F. LIND-RIEHL and O. GAILING
Forest Resources and Environmental Sciences, Michigan Technological University, 1400 Townsend Dr,
Houghton, MI 49931, USA
Oaks (Quercus spp.) provide a model system to study local adaptation since they maintain species
identity despite frequent interfertile hybridization. Genome scans between two European white oak
species have found a largely homogenized genome resulting from interspecific gene flow. However,
a few genomic areas showed high interspecific differentiation thought to be involved in the
maintenance of species identity through divergent selection. Quercus rubra and Q. ellipsoidalis, two
interfertile North American oak species, show differences in flowering time and adaptations to
drought. Previously, we discovered a genic microsatellite nearly fixed on alternative alleles in each
species. This locus has a putative function as CONSTANS-like gene, which is thought to be involved in
flowering time and growth. To further elucidate the basis of this differentiation we have begun
sequencing the coding region of this gene in individuals from both species. Our initial findings
indicate that the differences in allele frequencies are the result of sequence variability in the
microsatellite motif that encodes a poly-Q repeat potentially involved in transcription regulation or
protein stabilization. We plan to continue this work by sequencing additional areas around the
microsatellite to determine whether or not surrounding areas display variations associated with
species differences.
P24
Identifying microRNAs involved in Regeneration of Secondary Vascular
System in 4 Populus tomentosa Carr.
F. TANG 1 , H. WEI 2 and M-Z LU 1
1 State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing 100091,
China; 2 School of Forestry Resources and Environment Science, MTU, USA
Wood formation is a complex developmental process governed primarily by a regulatory
transcription network. MicroRNAs can exert regulatory roles over transcription of their target genes
involved in plant growth and development. We used the regeneration of the secondary vascular
system established in Populus tomentosa to harvest tissues generated from differentiating xylem in
a time series for small RNA high-throughput sequencing. 209 known and 189 novel miRNAs were
identified and Degradome sequencing analysis was then performed and 223 and 126 genes were
obtained. GO enrichment of these target genes revealed that the targets of 15 miRNAs were
enriched in the auxin signaling pathway, cell differentiation, meristem development and pattern
specification process, which were main biological events during the regeneration of secondary
vascular system. This study provides the basis for further analysis of these miRNAs to gain insight
into their regulatory roles in wood development in trees.
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