Dual roles of the serine/arginine-rich splicing factor SR45a in promoting and interacting with nuclear cap-binding complex to modulate the salt-stress response in Arabidopsis
- 1 April 2021
- journal article
- research article
- Published by Wiley in New Phytologist
- Vol. 230 (2), 641-655
- https://doi.org/10.1111/nph.17175
Abstract
Alternative splicing (AS) is emerging as a critical co-transcriptional regulation for plants in response to environmental stresses. Although multiple splicing factors have been linked to the salt-sensitive signaling network, the molecular mechanism remains unclear. We discovered that a conserved serine/arginine-rich (SR)-like protein, SR45a, as a component of the spliceosome, was involved in post-transcriptional regulation of salinity tolerance in Arabidopsis thaliana. Furthermore, SR45a was required for the AS and messenger RNA (mRNA) maturation of several salt-tolerance genes. Two alternatively spliced variants of SR45a were induced by salt stress, full-length SR45a-1a and the truncated isoform SR45a-1b, respectively. Lines with overexpression of SR45a-1a and SR45a-1b exhibited hypersensitive to salt stress. Our data indicated that SR45a directly interacted with the cap-binding complex (CBC) subunit cap-binding protein 20 (CBP20) which mediated salt-stress responses. Instead of binding to other spliceosome components, SR45a-1b promoted the association of SR45a-1a with CBP20, therefore mediating salt-stress signal transduction pathways. Additionally, the mutations in SR45a and CBP20 led to different salt-stress phenotypes. Together, these results provide the evidence that SR45a-CBP20 acts as a regulatory complex to regulate the plant response to salt stress, through a regulatory mechanism to fine-tune the splicing factors, especially in stressful conditions.Funding Information
- National Natural Science Foundation of China (31870234, 31970292, 31972357, 3177187)
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