W282 Differential Transcriptomes During Forming Of Epigenetic Memory In Norway Spruce

Date: Sunday, January 15, 2012
Time: 8:50 AM
Room: Sunrise
Igor Yakovlev , Norwegian Forest and Landscape Institute, Ås, Norway
YeonKyeong Lee , Department of Plant and Environmental Sciences, Norwegian University of Life Sciences, Ås, Norway
Bjorn Rotter , GenXPro-GmbH, Frankfurt am Main, Germany
Tore Skrøppa , Norwegian Forest and Landscape Institute, Ås, Norway
Øystein Johnsen , Department of Plant and Environmental Sciences, Norwegian University of Life Sciences, Ås, Norway
Jorunn Olsen , Department of Plant and Environmental Sciences, Norwegian University of Life Sciences, Ås, Norway
Carl Gunnar Fossdal , Norwegian Forest and Landscape Institute, Ås, Norway
Epigenetic memory marks establishment in Norway spruce occur exclusively during embryogenesis in response to environmental impact, and the epitype is fixated by the time the embryo is fully developed without a change in the DNA sequence. We started large scale studies aimed on identifying and characterizing of genes and regulatory elements involved in the initiation, maintenance, and heritability of epigenetic memory using candidate genes and next generation sequencing approaches. Molecular mechanisms of formation of epigenetic memory were studied on the same full-sibs family zygotic embryo in vitro cultures developed in cold (18°C) and warm (30°C) environmental conditions from proliferation till mature embryo stages.

Initially we had found large set (64) of Arabidopsis epigenetic regulator gene homologs in spruce. In general, known epigenetic related genes are very well represented among spruce ESTs. Analysis of the transcription patterns of these genes using RT-PCR in epigenetically different embryogenic samples reveal specific transcription patterns on different stages of embryogenic development dependent on epitype. We are expecting to determine certain stages during embryogenesis when epigenetic memory marks are forming. At the same time, nearly no differences in transcription levels of studied genes had been found in seedlings (4 month old), originated from full-sib families clearly differed in epigenetic response.

Using MACE (massive cDNA 3ʹ-end sequencing) deep mRNA sequencing on the Illumina GSII platform, we analyzed P. abies transcriptomes by comparison warm and cold originated “embryonic epitypes” developed in cold and warm environmental conditions. Significant differences in transcriptomes between epitypes revealed by high-throughput sequencing will be discussed.