The Arabidopsis pre-mRNA 3' end processing related protein FIP1 promotes seed dormancy via the DOG1 and ABA pathways

Seed dormancy is an important adaptive trait to prevent germination occurring at an inappropriate time. The mechanisms governing seed dormancy and germination are complex. Here, we report that FACTOR INTERACTING WITH POLY(A) POLYMERASE 1 (FIP1), a component of the pre-mRNA 3' end processing machinery, is involved in seed dormancy and germination processes in Arabidopsis thaliana. FIP1 is mainly expressed in seeds and the knockout of FIP1 causes reduced seed dormancy, indicating that FIP1 positively influences seed dormancy. Meanwhile, fip1 mutants are insensitive to exogenous ABA during seed germination and early seedling establishment. The terms 'seed maturation' and 'response to ABA stimulus' are significantly enriched in a gene ontology analysis based on genes differentially expressed between fip1-1 and the wild type. Several of these genes, including ABI5, DOG1 and PYL12, show significantly decreased transcript levels in fip1. Genetic analysis showed that either cyp707a2 or dog1-5 partially, but in combination completely, represses the reduced seed dormancy of fip1, indicating that the double mutant cyp707a2 dog1-5 is epistatic to fip1. Moreover, FIP1 is required for CFIM59, another component of pre-mRNA 3' end processing machinery, to govern seed dormancy and germination. Overall, we identified FIP1 as a regulator of seed dormancy and germination that plays a crucial role in governing these processes through the DOG1 and ABA pathways.