Jinghong Zhang, first author of The PPR-SMR protein ATP4 is required for editing the chloroplast rps8 mRNA in rice and maize
Current Position: Ph. D. candidate, National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, China
Education: Ph. D. in Huazhong Agricultural University; B. S. in Huazhong Agricultural University; B. Phil. in Huazhong University of Science & Technology
Non-scientific Interests: biking, hiking, volleyball, philosophy
Brief bio: I have been interested in plant science and human thoughts since high school. So, I selected biology as my main major and philosophy as my second major at university. As an undergraduate, I was attracted by chloroplast that conduct photosynthesis. Therefore, I chose to join the lab of Dr. Fei Zhou to study chloroplast gene regulation as my Ph. D. program. My first finding of this study is the rice atp4 mutant had fewer tillers than the wild type, which had not been reported in previous studies. However, I felt a little bit frustrated at first, as ATP4 is a well studied P-type pentatricopeptide repeat (PPR) protein in Arabidopsis and maize, and I found that the molecular defects in osatp4 are very similar to those reported previously in maize, including defects in accumulation of the ATP synthase and in the stability of dicistronic rpl16-rpl14 transcripts. It might be hard to make a breakthrough on this study. Luckily, once I unintentionally planted the osatp4 mutant in the field at a relatively late time (almost in autumn, not a suitable time for rice growth). Unexpectedly, all the osatp4 mutant plants exhibited a pale-green phenotype. Based on this observation, we further proved that the osatp4 mutant is cold sensitive. Another surprising finding is that the P-type PPR protein ATP4 is required for the mRNA editing of chloroplast rps8 in rice and maize. More importantly, we proved that the defect in the editing of rps8 transcript is not just a secondary effect due to the defect in the accumulation of rpl16–rpl14, which is cotranscribed with rps8. For this, I would like to acknowledge the scholarship granted by HZAU and Professor Alice Barkan for taking me as an exchange student in the University of Oregon. Prof. Barkan’s lab study the mechanisms employed by the PPR family and they investigated lots of maize PPR mutants. She kindly provided us with zmpgr3 and zmatp4. This work is of wide interest, because it sheds new light on the unanticipated role of PPR-SMR protein in RNA editing, highlights the importance of RNA editing under cold stress conditions; besides, the mechanism we proposed may also be applied to other PPR-SMR proteins.