Molecular insight into somaclonal variation phenomena from transcriptome profiling of cucumber (Cucumis sativus L.) lines

Somaclonal variation during in vitro culture is often an undesirable phenomenon but may also be a source of genetic variation useful for breeders. The molecular mechanisms underlying this phenomenon remain uncertain. In this study, we analyzed the fruit transcriptome of three independent cucumber lines using RNA-sequencing technology and performed an extensive in silico study to determine how somaclonal variation altered gene expression. Comparison of the transcriptome profiles with the wild-type cucumber ‘Borszczagowski B10’ revealed 418, 364, and 273 genes that were differentially regulated. We performed bioinformatic functional analysis, gene ontology classification, molecular network analysis, and explored differentially expressed genes associated with processes such as protein and nucleic acid binding, enzyme activity, signaling, transport, sugar and lipid metabolism. We determined that the differential gene expression may be caused by polymorphism in the genic region and may also be a result of interaction among molecular networks, which triggers specific pathways. The somaclonal variation is the effect of the environmental impact on the physico-chemical state of the cell and DNA changes that influence gene expression and affect molecular networks.