Conservation and functional influence of alternative splicing in wood formation of Populus and Eucalyptus

Background: Wood formation in tree species is regulated by multiple factors at various layers. Alternative splicing (AS) occurs within a large number of genes in wood formation. However, the functional implications and conservation of the AS occurrence are not well understood. Results: In this study, we profiled AS events in wood-forming tissues of Populus and Eucalyptus, and analyzed their functional implications as well as inter-species conservation. 28.3% and 20.7% of highly expressed transcripts in the developing xylem of Populus and Eucalyptus respectively were affected by AS events. Around 42% of the AS events resulted in changes to the original reading frame. 25.0% (in Populus) and 26.8% (in Eucalyptus) of the AS events may cause protein domain modification. In the process of wood formation, about 28% of AS-occurring genes were putative orthologs and 71 conserved AS events were identified in the two species. Conclusion: Through analysis of AS events in developing xylem of two tree species, this study reveals an array of new information regarding AS occurrence and function in tree development.