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As plants cannot move away from suboptimal conditions, they have developed various physiological and molecular defence systems. For instance, mitochondria have been shown to play important roles in perception and response to environmental stress conditions. To allow efficient coordination between these organelles and the rest of the cell, a signalling network is in place that mediates feedback communication between mitochondria and the nucleus. This organelle-to-nuclear communication is termed ‘retrograde’ signalling and affects nuclear gene expression. One type of retrograde signalling that has been studied extensively in animal systems is the mitochondrial unfolded protein response (UPR^mt). In plants, this pathway has not been studied in detail until recently, and key transcriptional pathways that mediate UPR^mt in plants were largely unknown. Using comparative transcriptomics we have now identified a signalling pathway that mediates common responses to UPR^mt in Arabidopsis thaliana.  Furthermore, an independent and highly transient gene expression pathway, which is induced within 10-30 minutes after mechanical stimulation, targets a range of mitochondrial stress marker genes, but also a wide range of genes involved in defence and jasmonic acid (JA) signalling. Our results show that the MYC2/3/4 transcription factors are key players in mechanical stress-induced signalling and orchestrate transient JA release in a positive feedback loop.