Supplementary Table S1: Primers used in this study The following primers (purchased from Eurofins MWG Operon) were used for the cDNA amplification in the RT-PCR experiments. Primer Sequence (5‘-3‘) rnpB fw AACTATGACTACCCGCCAGCC rnpB rev GGCTTTGCCCAAAGCAAATCG ocp fw GGATCAACACCCATGTTGAC ocp rev ACGGATGCAGTTTGCTGAAG sodB fw GACTCCTCTAAGGTGGGAATC sodB rev CCCAGACATCCAAGGTTAAG pgp fw TTACCTCTAGGGAAATCC pgp rev TATCTCTGGTTTCATCCC glyk fw GCGAATTCTGCCACACTCAC glyk rev GTCCTCGCCAAATCAATCGG isiA fw GGGTCAAGCGCGTAAATTTC isiA rev CAAATCCCGCCACCAATTAG ndaF fw ATTGCGGCAGAAACGGCTGCT ndaF rev ATCGGGTTTACGGCTTTGCACT Gene rnpB (Ribonuclease P) Accession locus tag nsp30860 ocp (Orange carotin protein) nsp46020 sodB (Fe-superoxide dismutase B) nsp31650 pglp (Phosphoglycolate phosphatase) nsp48780 glyk (Glycerate kinase) nsp44980 isiA (CP43’ chlorophyllbinding protein; PsbC homolog) ndaF (nodularinsynthetase subunit) nsp37510 nsp42160 Supplementary Table S2: Overview of transcriptome mapping. Control 0.5 h HL+O2 stress 3 h HL stress Library size 41,519,905 39,503,192 38,851,231 Mapped Reads 40,577,305 38,780,157 37,828,087 Mapped non-rRNA 28,214,827 (68%) 27,354,006 (69%) 25,567,480 (66%) Supplementary Table S4: Quantitative evaluation of the dRNAseq analysis. Number of genes and transcription start points (TSS) associated with an at least 3fold increased read number in cells exposed to combined high light/oxidative stress (HL+O2) for 0.5 h or to sole high light (HL) stress for 3 h in relation to the control. Number of TSS 3-fold increase (total) gTSS iTSS aTSS nTSS 3 h HL 0.5 h HL+O2 353 473 133 98 92 30 220 81 115 57 Percentage of total changes 3 h HL 0.5 h HL+O2 51.0 23.1 17.6 8.3 52.1 20.1 15.4 12.4 Supplemental Table S5: Quantitative evaluation of the RNAseq analysis. Number of genes and transcription start points (TSS) associated with an at least 3fold decreased read number in cells exposed to combined high light/O 2 (HL+O2) for 0.5 h or to sole high light (HL) stress for 3 h in relation to the control. Number of TSS 3-fold decrease (total) gTSS iTSS aTSS nTSS 3 h HL 0.5 h HL+O2 567 340 149 176 161 81 54 133 114 39 Percentage of total changes 3 h HL 0.5 h HL+O2 36.0 24.4 28.0 11.6 24.8 30.1 33.3 11.8