De novo transcriptome assembly and expression analysis provide insights into the molecular basis of heat response in Nothofagus pumilio

ARANA, MARÍA VERÓNICA; ZIEGENHAGEN, BIRGIT; MARCHELLI, PAULA; BELLORA, NICOLÁS; ESTRAVIS BARCALA, MAXIMILIANO; HEER, KATRIN

Santiago

Workshop; EMBO Workshop: Integrative biology ? From molecules to ecosystems in extreme environments; 2019

European Molecular Biology Organization (EMBO)

Nothofagus pumilio is an endemic tree of the southern temperate forests of Argentina and Chile. It constitutes a key ecological species, distributed across a wide latitudinal (36 to 55°S) and altitudinal range. Moreover, its  wood is appreciated and used due to its high quality. Global Climate  Change (GCC) predictions for Patagonia indicate a rise in the daily mean  temperatures, which will affect the ecological niches of native species, with tremendous ecological and societal implications. The aim of this  study was to gain insight into stress responses induced by heat in N.  pumilio, through the generation the first transcriptomic resource with annotations for this species, and the study of changes in protein-coding transcripts in response to heat through differential expression analysis.  mRNA libraries from whole leaves sampled after two days at 20°C and 34°C were prepared and sequenced in an ionTorrent Proton device. De novo assembly yielded 81,761 contigs, with a high read utilization rate  (93%) and more than 95% Core Eukaryotic Genes present. This  constitutes the most complete -omic resource for Nothofagus as of today. Annotation against Arabidopsis thaliana proteome resulted in 36,371 annotated contigs. A total of 1081 contigs were differentially expressed between temperatures according to DESeq software. Amongthese, at 34°C we observed genes involded in flavonoid and phenylpropanoid biosynthesis, de novo protein folding, and proteasome activity among others. This work provides the first transcriptome data and global profiles of gene expression in N. pumilio, generating a substantial contribution to research related with stress responses of forestry species. The differentially expressed genes identified in this study may provide genetic resources for the improvement of growth and production in N. pumilio and other tree species of economic value in a context of GCC.