Transcriptome analysis of transcription factors and glucosinolate metabolism in rocket (Diplotaxis tenuifolia L.)

Rocket (Diplotaxis tenuifolia L.) is widely used in fresh-cut salads and it is appreciated by consumers for its nutraceutical and sensorial properties. The evaluation of quality in ready-to-eat vegetables over the production pipeline is a crucial need for the fresh-cut industry. Analysis of the transcriptome allows studying the transcriptional events that take place in an organism under different physiological conditions. In this study rocket has been subjected to seven different stress conditions, both pre- and postharvest, and transcriptome analysis was employed to study the changes induced in specific pathways or gene families. Plants were grown using hydroponic systems in controlled growth chambers for 3 weeks prior to stress treatment. Pre-harvest stress included salinity, heat radical stress, and nitrate deficiency, while post-harvest stress was chilling, wounding, dark and water stress. Sampling was performed after 24 h and total RNA was extracted from stressed and control plants and sequenced with a two paired-end Illumina sequencing platform. Preliminary results from the analysis of the transcription factors which were influenced by stresses are presented. Moreover the main genes in glucosinolate metabolism were identified from the libraries and the changes in expression in response to different stresses are reported. Among the 33874 transcripts found, 2188 were identified as putative transcription factor genes and were clustered into groups corresponding to the most representative transcription factors families. From the functional analysis, a total of 181 genes involved in glucosinolate metabolism were identified. Results suggest an involvement of these compounds in plant stress responses. The data obtained from this work will help to shed more light on the mechanisms of stress response in rocket, with regards to the regulatory network and to the involvement of specific compounds which cover an important role in plant physiology and in human nutrition.