Development and Analysis of a Reference Transcriptome of Cultivated Strawberry

Strawberry (Fragaria × ananassa) is considered a non-climacteric fruit. As a consequence, knowledge about the regulation of the growth and ripening processes has lagged behind the vast information available on climacteric fruits.

The diploid woodland strawberry, Fragaria vesca, with a small and sequenced genome, is the actual model for genomic studies in strawberry. In the last two years, a number of studies have used RNA-seq to generate transcriptome profiles of different tissues and stages of the diploid model but, up to our knowledge, there is not published a similar study on the cultivated strawberry F. x ananassa.

We used RNA-seq to generate transcriptome profiles for receptacle, achene, leaf and root. The receptacle and achene tissues were sampled at four different ripening stages (green, white, turning and red). We performed two different approaches to assemble the transcriptome at the different tissues and stages, (1) mapping the reads against the F. vesca model, and (2) “de novo” assembly of reads in a tissue-specific analysis. Results provide a systems-level view of molecular events with spatial and temporal resolution in this species. The data show that achene has the higher number of specific transcripts. In receptacle, highest number of stage-specific transcripts was found at the green stage, followed by the red stage.  

The comprehensive transcriptome data set, from fruit and other tissues, offers a new molecular insight into the fruit ripening process of the cultivated strawberry as a wealth of genomic resources for the strawberry and Rosaceae community.