Mutation of an RNase E/G-type en-doribonuclease, OsRNE, produces defective chloroplast and causes early seedling lethality in rice

Endoribonuclease E (RNase E) has been reported to play a vital role in chloroplast RNA metabo-lism. We characterized the function of the OsRNE (Oryza sativa RNase E) in rice. Analysis of mutant plants generated by CRISPR-Cas9 system revealed that RNase E is essential for survival of rice. The osrne mutant displayed a white phenotype at the seedling stage and did not survive past the three-leaf stage. Transcriptome analysis showed that most of the genes associated with photosynthesis and carbohydrate metabolism pathways were significantly down-regulated. Chlorophyll- and other pigment-related genes were also differentially expressed in the osrne mutant. Our findings demonstrated that OsRNE plays an important role in chlorophyll biosynthesis and chloroplast development in rice.

核糖核酸内切酶E（RNase E）已被报道在叶绿体RNA代谢中发挥关键作用。本研究对水稻来源的OsRNE（Oryza sativa RNase E）的功能进行了表征。通过对CRISPR-Cas9系统构建的突变植株进行分析，结果显示RNase E对水稻存活至关重要。osrne突变体在苗期呈现白化表型，且无法存活至三叶期之后。转录组分析表明，绝大多数与光合作用及碳水化合物代谢通路相关的基因均显著下调表达；叶绿素及其他色素相关基因在osrne突变体中也呈现差异表达模式。本研究结果证实，OsRNE在水稻叶绿素生物合成与叶绿体发育过程中发挥重要作用。