Figure 4.

ANAC017-dependent mitochondrial retrograde signalling does not require ethylene signalling and MPK6. (a,b) Enrichment score plots analysed by GSEA using microarray data of WT plants treated with antimycin A (AA). List of ethylene biosynthesis genes (GO:0071369; a) or response to ethylene stimulus genes (GO:0009693; b) was used as the gene set of interest. (c) Heat map of the expression of selected ethylene biosynthesis and signalling genes after AA treatment in WT, rao2-1 and nac017-1. High and low expressed genes are depicted in blue and green, respectively. (d,e) Expression of selected mitochondrial retrograde signalling marker genes in WT plants treated with AA or Dox and with ACC (d), or AgNO₃ (e). (f,g) Expression of selected mitochondrial retrograde signalling marker genes in WT and ethylene biosynthesis (eto1-1) and ethylene-insensitive (ein2-1) mutants, or in MAPK signalling mutants (mpk6-3, mpk6-4) treated with AA or Dox. For all gene expression analysis (d–g), 10-day-old seedlings grown on half-strength MS medium were sprayed water with 50 µM AA, 25 µg ml⁻¹ Dox or 0.1% EtOH (mock), and with or without additional supplementation with 100 µM ACC (d) or 50 µM AgNO₃ (e). Seedlings were left under standard growth conditions for 4 h prior analysis. Expression was determined by qRT-PCR and is relative to mock only treated WT. Data shown are the means + s.e.m. (n = 3). Asterisks denote a significant difference versus the same treatment without ACC (d), AgNO₃ (e), or versus mock-treated WT (f,g). Student's t-test (*p < 0.05, **p < 0.01).