Transcriptomic and physiological responses of Diplotaxis tenuifolia under heat stress

Climate change and the increase of temperature could induce heat stress and affect crop performance, plant growth and quality. For these reasons, plants response to heat stress has been largely investigated. Physiological, metabolic and morphological modifications can be observed, as well as alterations of cell and organelle and regulation of many genes, involved in multiple regulatory pathways. The objective of the work is to deepen the knowledge about Diplotaxis tenuifolia response mechanisms to heat stress from physiological and molecular perspectives to identify new strategies to assist rocket plants’ recovery phase. Plants were cultivated in a growth chamber under controlled conditions (24°C), and heat stress conditions (increased temperature to 37°C for 4 h day^‑1, for 4 days). For each condition (control vs. stressed), plant material has been sampled for physiological and molecular analyses. Several physiological parameters have been analyzed, including chlorophyll a fluorescence and pigments content, nitrate concentration and sugars content. Also, RNA-sequencing has been performed to underline molecular changes induced by high temperature. Chlorophyll fluorescence and physiological assays results confirmed the effect of the heat stress: a reduction of chlorophyll content and leaf functionality were observed. Sugars and nitrate content also show alteration due to heat stress. The transcriptomic profiling confirmed the heat stress effects on rocket plants, showing the different regulation of genes related to secondary metabolism, signaling, elements of membrane and photosynthetic machinery in the two conditions (control vs. heat). These data allowed a deeper understanding of the physiological and transcriptional mechanisms induced by heat stress in rocket and represent a useful basis for further studies.