AtMC1 Associates With LSM4 to Regulate Plant Immunity Through Modulating Pre-mRNA Splicing

Alternative splicing of pre-mRNAs is an important gene reg-ulatory mechanism shaping the transcriptome. AtMC1 is an Arabidopsis thaliana type I metacaspase that positively regu-lates the hypersensitive response. Here, we found that AtMC1 is involved in the regulation of plant immunity to the bacterial pathogen Pseudomonas syringae pv. tomato DC3000 and is physically associated with Sm-like4 (LSM4), which is involved in pre-mRNA splicing. AtMC1 and LSM4 protein levels both increased with their coexpression as compared with their separate expression in vivo. Like AtMC1, LSM4 negatively regulates plant immunity to P. syringae pv. tomato DC3000 infection. By RNA sequencing, AtMC1 was shown to modulate the splicing of many pre-mRNAs, including 4CL3, which is a negative regulator of plant immunity. Thus, AtMC1 plays a regulatory role in pre-mRNA splicing, which might contribute to AtMC1-mediated plant immunity.

Automated summary

The study reveals that AtMC1 regulates plant immunity to bacterial pathogens and is physically associated with LSM4. The protein levels of AtMC1 and LSM4 increase with coexpression in vivo. Additionally, AtMC1 modulates the splicing of pre-mRNAs, including 4CL3, which regulates plant immunity.