Transcriptome profiling reveals the regulatory role of CSA-mediated photoperiod-dependent male fertility

The discovery of photoperiod-sensitive male genic sterile (PGMS) lines started the development of two-line hybrid rice, which is critical to sustain production of high-yielding hybrid rice varieties. Previous reports about the PGMS lines are mainly focused on the gene cloning and their function description. The mechanisms by which PGMS lines perceive changes in photoperiod and transmit those signals to elicit downstream effects is rarely mentioned. In this work, we described the effects of photoperiod on gene expression in wild type (WT) and csa, a PGMS line, flag leaves and anthers to identify putative central factors that transduce photoperiod signals via CSA in both leaves and anthers. We also dissect the potential mechanisms that: cause csa-induced sterility under SD conditions; partially restore fertility in csa anthers under LD conditions; and finally, are responsible to restore full WT fertility under LD and SD conditions. These results provide an overview how the PGMS rice perceives and transmits photoperiod changes, and how the CSA and its homologs response to the environmental cues by regulating down-stream gene expression. That will be helpful to understand the photoperiod-sensitive mechanism and identify new photoperiod-sensitive genes. Overall design: At Stage12 of the anther development, flag leaves were collected at 08:00,12:00,16:00,20:00,00:00, 04:00 for a whole period under short-day(12 hours light) and long-day(14.5 hours light) condition. Anther was collected at 16:00 and 4:00 from the same tillers with the flag leaves. Each sample have two biological replicates.