35th NPS abstract book

P31
Wood formation in the real world
N. Q. NGUYEN 1 , D. JANZ 1 , C. CARSJENS 1 , G. LOHAUS 1 , T. IVEN 2 , I. FEUSSNER 2 and A. POLLE 1
1 Dept. for Forest Botany and Tree Physiology, Georg-August Universität Göttingen, Büsgenweg 2,
37077 Göttingen, Germany; 2 Dept. for Plant Biochemistry, Georg-August Universität Göttingen,
Justus von Liebig Weg 11, 37077 Göttingen, Germany
In temperate ecosystems, wood formation of deciduous tree species undergoes seasonal
fluctuations, usually with the production of larger vessels early and the formation of smaller vessel
lumina, more fibers and thicker cell walls towards the end of the growth phase. The transcriptional
networks and hormonal regulation underlying wood formation of non-model trees has barely been
studied. Here, we investigated the formation of beech wood (Fagus sylvatica L.). Although beech is a
key stone species in temperate European forests, genomic information is lacking. To increase our
knowledge on wood formation of beech, we used RNA sequencing of the developing xylem of
mature field grown trees located at two field sites. The transcriptomic data were related to the
hormonal status and wood anatomy employing weighted gene correlation network analysis.
Thereby, co-regulated genes and hormones were assigned to the formation of specific cell types.
Our analysis suggests that ABA (abscisic acid) is a main player in seasonal acclimation of the wood
structure balancing vessel lumina and fibre numbers.
P32
What are the drivers of non-coding plastome variation in the New Zealand
tree flora?
B. C. M. POTTER, A. J. DRUMMOND, R. D. NEWCOMB and W. G. LEE
School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, 1010, New
Zealand
The native tree flora of New Zealand is diverse (ca. 320 species), highly endemic (over 90%), and
situated on a landmass with a deep history of geographic isolation in the southern Pacific (ca. 80
Ma.). As a result this region provides an excellent system for the study of forest tree genetics, as the
lineages have estimable island colonisation ages, display a range of generation times and seed
dispersal strategies, and encompass a broad array of phylogenetic diversity – from tree ferns to tree
daisies. To better understand the drivers of non-coding chloroplast variation in forest trees, targeted
sequencing was performed (e.g. trnQ-rps16, rpL32-trnL, psbA-trnH, rpoB-trnC, and trnL-trnF) on
numerous accessions of a broad selection of 20 widespread species. The results show a direct
correlation between lineage age and genetic variation in some taxa (e.g. Nothofagus spp., Nestegis
spp., Rhopalostylis sapida), highlighting the importance of the temporal driver. However, in other
species the opposite pattern was recovered, with a recently colonised tree (Geniostoma
ligustrifolium) representing the most genetically variable species – potentially owing to its rapid
generation time. While one of the most ancient species in the flora (Agathis australis) was found to
be one of the least variable – possibly owing to a slow-down in the evolutionary rate of the
araucarian plastome. These findings are discussed along with directions for further research.
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