35th NPS abstract book

P28
A developmental and genetic study of petal-less neotropical poppy trees
N. PABÓN-MORA 1* , C. ARANGO OCAMPO 1 , J. F. ALZATE 2 and F. GONZÁLEZ 3
1 Instituto de Biología, Universidad de Antioquia, AA 1226; 2 Centro de Secuenciación Genómico
Nacional, Universidad de Antioquia, AA 1226; 3 Instituto de Ciencias Naturales, Universidad Nacional
de Colombia, AA 7495
Flowers of most Papaveraceae (760 spp.) exhibit a dimerous groundplan with 2 deciduous sepals, 4
petals, many stamens and 2-8 carpels. The genera Bocconia (9 spp.) and Macleaya (2 spp.) are
atypical in their tree- or shrubby habit, and in having perianth-less flowers. By comparing flower
development in B. frutescens, M. cordata and its closely related species Stylophorum diphyllum, we
show that petal-to-stamen homeosis occurs early in development, but different ontogenetic
pathways underlie petal-loss in Bocconia and Macleaya. In order to explore the genetic basis of
apetaly, we generated a floral transcriptome of B. frutescens and identified all MADS-box
transcription factors that are part of the ABCE genetic model of floral development. We present data
on the evolution of these genes in the Ranunculales and their expression in dissected floral organs,
leaves and fruits in B. frutescens We also propose that the lack of expression of an AP3-3 ortholog is
responsible for such apetaly, as it occurs in species of Ranunculaceae. We identified local
duplications in FUL-like and PI genes likely resulting in pseudogenization and neofunctionalization,
respectively. Based on the number of copies and patterns of expression, we propose a modified
ABCE model for the petal-less poppy trees.
P29
Microevolutionary patterns of a resistance mechanism in white spruce
G.J. PARENT 1 , I. GIGUÈRE 1 and J.J. MACKAY 1, 2
1 Centre d’étude de la Forêt, Département des Sciences du Bois et de la Forêt, Université Laval, G1A
1V6, Québec, Canada; 2 Department of Plant Sciences, University of Oxford, Oxford, OX1 3RB, UK
The accumulation of two foliar acetophenone compounds (piceol and pungenol) plays a key role in
the defense of white spruce (Picea glauca) against spruce budworm (SBW, Choristoneura
fumiferana). Variability in the expression of a beta-glucosidase, PGβGLU-1, responsible for their
release was linked to SBW resistance. This novel resistance mechanism is constitutive, genetically
transmissible and variable in the natural white spruce population. We were interested in
characterizing its microevolutionary patterns to better understand its importance. Levels of Pgβglu-1
transcripts and toxic acetophenones were measured in white spruce from multiple provenances and
preliminary results indicated a clear geographic pattern. Foliage expression of Pgβglu-1 was lower in
provenances south of the 48th parallel. This result may be accounted for by lower selection pressure
exerted by SBW associated with a reduced survival rate at the southern limit of its distribution.
However, concentrations of piceol and pungenol in white spruce foliage did not follow the
geographic pattern found for gene expression. This suggests that control of these specific
acetophenone compounds may also be affected by other factors than the expression of Pgβglu-1.
We are currently working to find other members of the biochemical pathway and regulatory
network through association testing and other genome analysis methods.
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