Transcriptomic analysis of juvenile wood formation during the growing season in Pinus canariensis

A noticeable proportion of low transcribed genes involved in wood formation in conifers may have been missed in previous transcriptomic studies. This could be the case for genes related to less abundant cell types, such as axial parenchyma and resin ducts, and genes related to juvenile wood. In this study, two normalized libraries have been obtained from the cambial zone of young individuals of Pinus canariensis C. Sm. ex DC, a species in which such cells are comparatively abundant. These two libraries cover earlywood (EW) and late-wood (LW) differentiation, and reads have been de novo meta-assembled into one transcriptome. A high number of previously undescribed genes have been found. The transcriptional profiles during the growing season have been analyzed and several noticeable differences with respect to previous studies have been found. This work contributes to a more complete picture of wood formation in conifers. The genes and their transcription profiles described here provide a useful molecular tool for further studies focused on relevant developmental issues, such as wound response and the formation of traumatic wood, re-sprouting, etc., presumably related to those cells.