Welcome to the ISHS Brassica 2012 Symposium

Poster A-2
STRUCTURAL AND FUNCTIONAL DIVERGENCE OF THE ABI1 HOMEOLOGOUS
GENES IN BRASSICA NAPUS
Babula-Skowrońska D. 1 *, Ludwików A. 2 , Cieśla A. 1 , JędryczkaM. 1 1, 2
, Sadowski J.
1 Institute of Plant Genetics, Polish Academy of Sciences, Strzeszynska 34, 60-479 Poznan, Poland
2 Department of Biotechnology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89,
61-614 Poznan, Poland.
E-mail: dbab@igr.poznan.pl
Whole-genome duplication as result of the paleopolyploidyzation process and the extensive
chromosomal rearrangements have been confirmed by numerous studies in the Brassica species. A
consequence of this process is duplication of individual genes and hence their large proportion are
members of multi-gene families. Despite the sequence homology, these genes often exhibit
significant differences in the expression patterns in effect of their sub- or neofunctionalization
process. Understanding of the evolution and functional divergence of duplicated genes is significant
for genetic improvement of crops and formation of new phenotypes. In this study we intended to
determine mechanisms of structural and functional divergence of the detected ABI1 homeologous
genes arising from polyploidy in Brassica napus. The ABI1 gene encodes protein phosphatase 2C
and belong to PP2C family, group A. It is a key component and repressor of the abscisic acid
(ABA) signaling pathway involved in the regulation of multiple signaling pathways through
reversible phosphorylation of proteins. In Arabidopsis ABI1-encoding gene was identified as
unique gene, but is represented by 6 copies in the allotetraploid B. napus genome. We identified and
initially characterized 5 out of 6 ABI1 homeologs in B. napus. Based on sequence analysis, we
determined their structure and genome origin (A or C genome). Although, a high sequence and
structure similarity level among these ABI1 homeologs is observed, they exhibit changes in the
expression profiles in different tissues, stages of development and in response to the abiotic and
biotic stresses. One of major mechanism regulating the expression of duplicated genes (except
changes in DNA sequence) are cis-acting effects. Therefore, we initiated the detailed analysis of
gene expression regulation by using promoter-GUS and -GFP fused constructs. The promoter
activity of 2 homeologs with GUS and GFP assays is analyzed in transgenic B. napus and A.
thaliana. Additionally, in preliminary analysis, in silico identification of potential cis-regulatory
elements in promoter regions of all ABI1 homeologs was carried out. The selected aspects of this
studies will be discussed.
6 th International Symposium on Brassica and 18 th Crucifer Genetic Workshop - Catania (Italy) 12 - 16 November 2012
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