Genome-wide profiling of long non-coding RNAs from tomato and a comparison with mRNAs associated with the regulation of fruit ripening

Background: Long non-coding RNAs (lncRNAs) are involved in multiple biological processes in both mammals and plants. There is growing evidence that they are associated with development; but their expression and regulation during fruit ripening in the model plant tomato (Solanum lycopersicum) has yet to be described. Results: Following integration of 134 RNA-seq data sets, we identified 79,322 putative lncRNAs, consisting of 70,635 lincRNAs, 8085 antisense non-coding RNAs (ancRNAs) and 602 sense lncRNAs (slncRNAs). lncRNAs had specific features that are distinct from mRNAs, including tissue-specificity, and shorter and fewer exons. Notably, more than 5000 of the novel lincRNAs were found to be expressed across the mature green (MG), breaker (BR) and breaker plus 7 days (BR + 7) developmental stages. The differently expressed lincRNAs had different DNA methylation profiles from the mRNAs. Conclusions: Integrating transcriptome datasets and genome-wide screening enabled the identification of a comprehensive set of tomato lncRNAs. Here, we found that the lncRNAs DNA methylation profiles were different from those of mRNAs. This will help future investigation of lncRNA function, especially for the dissection of the molecular mechanisms involved in the regulation of fruit development.