The chloroplast splicing and ribosome maturation (CRM) domain proteins have functions in the splicing of chloroplast gene introns. Several CRM domain proteins have been discovered to be involved in chloroplast development in many plants, but their functions in rice are still yet to be known. To elucidate more on this, scientist Qiang Zhang from Chinese Academy of Sciences and colleagues used CRISPR-Cas9 technology. The results were reported in the International Journal of Molecular Sciences.

Albino mutants oscaf1 were generated through the editing of OSCAF1 with two CRM domains using CRISPR-Cas9. The mutants eventually died at seedling stage. It was observed that the mutants had fewer chloroplast numbers and damaged chloroplast structures.OsCAF1 was found in the chloroplast, and were in high amounts in green tissues. Furthermore, OsCAF1 promoted the splicing of group IIA and group IIB introns, which could be influenced by its interaction with OsCRS2.

The findings revealed that OsCAF1 controls chloroplast development by influencing the splicing of group II introns.

Read the full paper in the International Journal of Molecular Sciences.

Figure 1. Knockout of OsCAF1 produces the albino phenotype in seedlings. (A) Diagram of CRISPR/Cas9 system for editing OsCAF1. (B) Schematic diagram of the targeted site in OsCAF1. (C) Mutation types of four positive plants in T₀ generation. The targeted sequences are in blue letters. The protospacer adjacent motif (PAM) sequences are in red letters. The number of nucleotides at both sides of the target sequences is 18 bp. (D) Phenotypes of four positive plants at seedling stage. Scale bar, 1 cm.