Bacterial Strains，Media，and Growth Conditions

R.capsulatus rifampicin-resistant strain SB1003 was used.The cells were grown on malate-minimal RCV medium［20］.Those cells growing photoheterotrophically were cultured at 30℃in 170-ml screw-cap bottles filled completely to the top.Light was provided by a bank of lumiline lamps at high light intensity（30 W/m2）or low light intensity（6 W/m2）.Darkshift experiments were performed by wrapping the growth vessels from high light-grown cells with aluminum foil and incubating them for 1 h at 30℃.Highly aerobic growth（designated as high O2）was maintained by chemoheterotrophic culturing of the cells（80 ml of medium in a 1，000-ml Erlenmeyer flask）on a gyratory shaker（200 rpm）.Semiaerobic growth（designated as low O2）was carried out in vessels filled to 80%capacity with growth medium on a gyratory shaker（200 rpm）.The cells at mid-log phase（4—7）×108 cells per ml）were harvested for measurement of absorption by Bchl and chromatophores and for RNA extraction.(https://www.daowen.com)