Generation and Characterization of oscsn1 Mutants Reveal That OsCSN1 Regulate ABI5 Degradation In Seedling Growth
Abstract In many developmental processes in plants, the COP9 signalosome (CSN) plays multiple effects. It is a complex composed of eight subunits CSN1 to CSN8, which is very conservative.The CSN1 acted in a network of signal transduction pathways critical for plant development. Although there are many studies on the CSN1 subunit in Arabidopsis, there are few studies on the CSN1 subunit in rice. We used CRISPR/Cas9 technology to edit the CSN1 subunit of Oryza sativa subsp. japonica (rice). We screened knockout mutants and then observed phenotypic changes of the mutants under different light conditions. Previous research demonstrated that atCSN1 promotes seed germination by regulating ABA effector ABI5. However, we found that this mechanism did not occur in rice. In the oscsn1 mutant, ABI5 protein was rapidly degraded at the seedling stage, and it did not show the displayed defects in degradation of ABI5. As a result, the mutants exhibited weak dormancy and the rapid growth phenotype of seedlings. Our observations demonstrate that osCSN1 plays a role in effecting growth and development by regulating protein turnover the ABA effector ABI5, but the direct the mechanism of their action and molecular targets are needed to explore.