Zea mays Raw sequence reads
Ubiquitination and deubiquitination are important post-translational regulations in eukaryotes. Recent studies in Arabidopsis showed that they could affect all plant growth and development aspects. However, there needed to be more knowledge about their involvement in maize kernel development.In this study, we worked on a novel EMS-induced maize kernel mutant ubp5, which had small and dark appearance, along with arrested embryo development and defectiveness in the endosperm. Through gene mapping and allelic verification, we identified that ZmUBP5 with c.1372C>T|p.Q458* mutation was the causal for this kernel mutant. ZmUBP5 was annotated as a ubiquitin-specific protease (UBP) with deubiquitinase activity, and it was localized to nuclear, while the stop_gained mutation could disrupt this. Omics analysis showed that the ubp5 mutation affected transcriptome, proteome, and ubiquitinome in maize kernel developent at a global level. Through protein interaction and degradation experiments, we proved that ZmUBP5 could interact with and might regulate the ubiquitination level of ZmEMB140. ZmEMB140 was annotated as a spliceosome-associated protein essential for splicing. Maize mutant with a stop_gained mutation (c.652C>T|p.Q218*) in ZmEMB140 showed smaller kernel size with smaller embryos and endosperm. Furthermore, we proved that ZmEMB140 was involved in pre-mRNA processing by affecting alternative splicing. ZmEMB140 could interact with four U6 snRNA-associated Sm-like proteins (LSM) and two pre-mRNA processing factors (PRP).Our study revealed for the first time the mechanism by which deubiquitinase ZmUBP5 is involved in the regulation of maize kernel development.