Materials and Methods

Bacterial strains，media and growth conditions R.capsulatus RifR strain SB1003 was used throughout this study.Mutants KZR9A12（crtA-），KZR9F4（crtI-），UAR87（RC-H-）and SB1007（bchC-）were used where indicated.Light intensities are denoted as follows：high light（HL），low light（LL），dark（D）；O2 conditions are denoted：high O2（O2），low O2（LO2）.Cell culture conditions are previously described［12］.

Absorption spectroscopy of pigments.See［13］.

Preparation of plasmid，M13 phage and oligonucleotide probes.See［12］.(https://www.daowen.com)

RNA isolation，dot blots and Northern hybridization.See［12］.