The 30th International Conference on Arabidopsis Research (ICAR 2019)

398 / 2019-02-20 14:07:24

Organellar RNA metabolism in Arabidopsis development and stress responses

RNA metabolism,Chloroplast,mitochondria,intron splicing,rRNA processing

Plenary track > RNA Biology

Chloroplast and mitochondrial gene expression is regulated mainly at posttranscriptional levels, including intron splicing, RNA processing, and RNA editing. Diverse nucleus-encoded RNA-binding proteins (RBPs) are targeted to chloroplasts or mitochondria and function as central regulators during RNA metabolism in cellular organelles. To understand the roles of organellar RNA metabolism in plant development and stress responses, we investigated the functions of RBPs such as pentatricopeptide repeat (PPR) protein, RNA helicase (RH), and S1 domain-containing protein (SDP) involved in chloroplast or mitochondria intron splicing and rRNA processing. Analysis of the Arabidopsis mutants demonstrated that PPR4, PPR19, and RH3 are essential for splicing of chloroplast or mitochondrial introns. In addition, PPR287 and SDP1 were shown to play an important role in the processing of chloroplast rRNAs. Impairment of the splicing and processing of organellar mRNAs and rRNAs in these mutants resulted in abnormal chloroplast structures, decreased photosynthetic activity, delayed growth, and altered stress response, suggesting that these RBPs are essential for chloroplast biogenesis and function and plant growth. Collectively, these findings point to the importance of nucleus-encoded chloroplast- or mitochondria- targeted RBPs in the posttranscriptional regulation of RNA metabolism in cellular organelles, which is crucial for plant development and stress responses.