Plant & Animal Genomes XV Conference Plant & Animal Genomes XV ConferenceJanuary 13-17, 2007
Town & Country Convention Center
San Diego, CA
Igor A. Yakovlev1 , Carl-Gunar Fossdal1 , Øystein Johnsen1 , Olavi Junttila2 , Tore Skrøppa1
We have prepared four subtracted cDNA libraries, forwards and reverses, representing genes predominantly expressed in a tree from early flushing (EF) and late flushing (LF) families of Norway spruce. Two subtracted libraries during four weeks before bud burst had been partially sequenced.
Differential screening reveals that in LF at seven weeks before the bud burst considerably upregulated senescence-associated genes, auxin-repressed proteins and several transcripts without similarities in the Database.
Partial sequencing is shown, that in the early library, ESTs encoding proteins of the photosynthetic apparatus, energy metabolism, stress (abiotic and biotic) and senescence related proteins were abundant. In the late library, ESTs encoding metallothionein-like and histone proteins as well as transcription factors were more abundant. We used quantitative RT–PCR to study the expression patterns of 45 chosen genes, and observed that the highest levels of activity for most genes were present when plants were still ecodormant. Late flushing is not a result of a simple delay in gene activity, but rather a consequence of an active transcriptional process. The putative role of the studied genes in regulation of bud burst timing is discussed. Among the candidate genes found, the most interesting ones were the DNA-binding factors, cold- and water-stress related genes and metallothioneins. Expression patterns of some genes involved in chemical modification of DNA and histones support our suspicion that epigenetic factors may be involved in the timing of bud burst. Some of the genes from the light- and cold-stress regulated pathways show different expression during bud burst initiation.