GSE138193
Diurnal transcriptomics analysis reveals the regulatory role of the circadian rhythm in super-hybrid rice LY2186
Heterosis, an important biological phenomenon wherein F1 hybrids exhibit better performance than any of their parents, has been widely applied; however, its underlying mechanism remains largely unknown. Here, we studied and compared the dynamic transcriptional profiles of super-hybrid rice LY2186 and its parents at 17 time points during 2 day/night cycles and identified 1,552 rhythmic differentially expressed genes (RDGs). Cluster and functional enrichment analyses revealed that the day- and night-phased RDGs were mainly enriched in the photosynthesis and stress response categories, respectively. Regulatory network analysis indicated that circadian-related RDGs are core components in both the day and night phases and extensively regulate downstream genes involved in photosynthesis, starch synthesis, plant hormone signal transduction, and other pathways. Furthermore, among the 282 RDGs mapped onto the quantitative tract loci of small intervals (=100 genes), 72.3% were significantly enriched in the yield, vigor, and anatomy categories. These findings provide valuable information for exploring heterosis mechanisms further and guiding breeding practices. Overall design: We constructed 51 ssRNA sequencing libraries of flag leaves of the super-hybrid rice Liangyou2186 (LY2186)and its parental lines including the male-sterile line SE21s and the restorer line  Minghui86 (MH86) at the grain-filling stage during 17 serial time points (circadian clock ZT0~ZT48, 3h interval).