Qiang Zhang, Lan Shen, Zhongwei Wang, Guanglian Hu, Deyong Re, Jiang Hu, Li Zhu, Zhenyu Gao, Guangheng Zhang, Longbiao Guo, Dali Zeng and Qian Qian

Int. J. Mol. Sci. 2019, 20(18), 4386; https://doi.org/10.3390/ijms20184386

Abstract

The chloroplast RNA splicing and ribosome maturation (CRM) domain proteins are involved in the splicing of chloroplast gene introns. Numerous CRM domain proteins have been reported to play key roles in chloroplast development in several plant species. However, the functions of CRM domain proteins in chloroplast development in rice remain poorly understood. In the study, we generated oscaf1 albino mutants, which eventually died at the seedling stage, through the editing of OsCAF1 with two CRM domains using CRISPR/Cas9 technology. The mesophyll cells in oscaf1 mutant had decreased chloroplast numbers and damaged chloroplast structures. OsCAF1 was located in the chloroplast, and transcripts revealed high levels in green tissues. In addition, the OsCAF1 promoted the splicing of group IIA and group IIB introns, unlike orthologous proteins of AtCAF1 and ZmCAF1, which only affected the splicing of subgroup IIB introns. We also observed that the C-terminal of OsCAF1 interacts with OsCRS2, and OsCAF1–OsCRS2 complex may participate in the splicing of group IIA and group IIB introns in rice chloroplasts. OsCAF1 regulates chloroplast development by influencing the splicing of group II introns.

See https://www.mdpi.com/1422-0067/20/18/4386

Figure 3. Chloroplast ultrastructure observation of WT (A,C) and oscaf1 mutants (B,D) mesophyll cell at the three leaves stage. cp, chloroplast, gl, grana lamella. Bars = 2.0 μm.