DNA/RNA Isolation from Chroomonas gyreus

For DNA/RNA isolation, G. theta was cultured in 200 ml f/2 medium for 7–14 days, as described earlier (Mix et al., 2018 (link)). G. theta cells were centrifuged at 3,000 x g and 21°C for 10 min. Total DNAs were isolated from the pelletized G. theta cells via the CTAB method and were stored at −20°C. Total RNAs of G. theta were extracted using the RNeasy Mini kit (Qiagen) and were promptly treated with DNAseI (Thermo Fisher Scientific), following the manufacturer's instructions, to remove potential genomic DNA contamination. cDNA was synthesized with the FastGene Scriptase II Kit (Nippon Genetics) using random hexamer oligonucleotides provided by the manufacturer. Synthesized cDNA was used for amplification of gene sequences with specific oligonucleotides (refer to Supplementary Table S4).