In animals and plants, circRNAs regulate gene expression and act as
sponges that inhibit the activity of microRNAs. This study aimed to
determine how specific circRNAs are expressed in rice grains at
different stages of grain filling, under normal and low light
conditions. We extracted total RNA from rice grains under low and
sufficient light conditions. Deep sequencing was performed using circRNA
libraries, and bioinformatics tools were used to identify the circRNAs.
In addition, we analyzed targeted messenger RNA functions using two
databases to predict the processes involved in rice grain development,
and we conducted real-time PCR on 15 of the circRNAs. During the grain
development process, 8015 candidate circRNAs were isolated, among which
the number of known circRNAs was 1661. We also found that the number of
circRNAs changed with the time of development. Among them, six circRNAs
acted as sponges that targeted more than two microRNAs at different
stages of development, and these circRNAs showed a regulatory pattern
consistent with the transcriptome sequencing results. However, no
differential circRNA expression was found under different light
treatments. These findings reveal a possible link between circRNA
regulation and the expression of the functional genes associated with
photosignal-mediated rice grain development.