Modulation of polyadenylation site selection and mRNA expression by CstF77 in response to thermal stress in Arabidopsis

The temperature is important for plant growth and development. Pre-mRNA 3’-end processing is involved in thermal response in plants. However, the role of CstF77, a key component of the polyadenylation machinery, in response to high-temperature stress remains unclear. In this article, we found that the loss of function of cstf77 mutants exhibit altered thermomorphogenesis. The full-length transcriptome sequencing revealed that polyadenylation sites (PASs) in transcripts from 1150 genes were shifted in the cstf77-2 at 23°C. Most of the PAS shifts were from proximal to distal sites. High temperature also caused PAS shifts in transcripts from 991 genes. The difference in nucleotide usage frequency between U and A in the upstream region of proximal PASs was more pronounced than that of distal PASs in the cstf77-2 , suggesting that CstF77 plays an important role in regulating the preferential use of specific nucleotides. Moreover, the selection of PASs and the transcriptional expression of some heat-responsive genes are regulated by both CstF77 and high temperature. We conclude that CstF77 plays a role in the primary root growth in response to thermal stress, probably by regulating the PAS selection and the transcript abundance of some heat-responsive genes. • CstF77 is involved in the thermal stress response, and loss-of-function mutations in CstF77 are resistant to high temperature. • CstF77 mediates distinct poly(A) signal identification between proximal and distal polyadenylation sites. • The selection of PASs and the transcriptional expression of some heat-responsive genes are regulated by both CstF77 and high temperature.