35th NPS abstract book

P41
Landscape genomics for climate adaptation in Eucalyptus trees
M. A. SUPPLE, J. BRAGG, R. ANDREW, A. NICOTRA, M. BYRNE, L. BROADHURST and J. O. BOREVITZ
The Australian National University, Canberra, ACT 2601, Australia
The rapid pace of climate change is threatening the survival of many species. Especially vulnerable
are long lived species with slow migration rates, which have limited ability to move with favorable
climatic conditions. Extensive reforestation projects are ongoing across Australia, providing the
opportunity to assist migration of potentially adaptive alleles. Eucalyptuses, which are foundation
species in forests and woodlands across Australia, are focal species of the reforestation effort. We
are using landscape genomic techniques to identify alleles associated with various climate conditions
in two Eucalyptus species. Using genotype by sequencing methods, we have genotyped hundreds of
samples across the distributions of each species. Each sampling location is associated with numerous
climate variables, enabling us to identify specific alleles associated with specific climatic conditions.
This association is suggestive of adaptation, which we can test experimentally in climate controlled
growth chambers. Populations harboring alleles that are potentially adaptive to predicted future
climates can be used as sources of seeds for reforestation, thereby assisting migration of the
adaptive alleles.
P42
Comparative analysis of pollen transcriptomes reveals distinct sucrose
utilization mechanisms in angiosperm trees
E. D. TRIPPE 1 , L.J. XUE 2, 3 , X. GU 1 , V. MICHELIZZI 2, 3 , V. E. JOHNSON 2, 3 , B. NYAMDARI 2, 3 , S.A.
HARDING 2, 3 1, 2, 3
and C. J. TSAI
1 Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA; 2 Warnell School of
Forestry and Natural Resources, University of Georgia, Athens, GA 30602, USA; 3 Department of
Genetics, University of Georgia, Athens, GA 30602, USA
Carbohydrate allocation is an important fundamental process during reproduction, and is best
understood in herbaceous annuals. Woody perennials exhibit distinct flowering phenology
(precocious versus serotinous flowering), but the genetic underpinning is poorly understood. We
found that flowering phenology is linked to pollen expression of distinct sucrose transporter (SUT)
family members. Plasma membrane SUTs are dominant in the pollen of herbaceous annuals, as well
as woody perennials with serotinous flowering, such as grapevine and Eucalyptus. In contrast, early
flowering Populus, willow and oak pollen show high transcript levels of tonoplast-localized SUT.
Additionally, our analysis reveals differential expression of vacuolar and cell wall invertases between
pollen of early- and late-flowering trees. The observation of differential compartmentalization of
sucrose transport and processing enzymes suggests alternative carbohydrate utilization mechanisms
in pollen during angiosperm evolution. Comparative gene co-expression analysis is underway to
identify other molecular candidates that are involved in different carbohydrate allocation pathways
during reproduction.
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