Zhang Chao, Wang Lengjing, Wang Zirui, Dai Qiang, Feng Haiyang, Xu Shu, Liu Xueju, Tang Jiaqi, Yu Hengxiu
Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Zhongshan Biological Breeding Laboratory/Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Agricultural College of Yangzhou University, Yangzhou, 225009, China.
Rice (N Y). 2025 Mar 12;18(1):14. doi: 10.1186/s12284-025-00771-x.
Chloroplasts are vital for photosynthesis, and their development necessitates proper expression of chloroplast genes. However, the regulatory mechanisms underlying rice chloroplast gene expression have not been fully elucidated. In this study, we obtained an albino mutant of rice, white seedling and lethal 1 (wsl1), which displays significantly decreased chlorophyll contents and impaired chloroplast ultrastructure. The causal gene Oryza sativa PEP-RELATED DEVELOPMENT ARRESTED 1 (OsPRDA1) was isolated using Mutmap + and verified by gene editing and complementary assays. The expression of OsPRDA1 is induced by light, and OsPRDA1 is localized in chloroplasts. Transcription sequencing revealed that genes related to photosynthesis were differentially expressed in wsl1. The expression levels of the examined plastid-encoded RNA polymerase (PEP)-dependent chloroplast genes are downregulated due to the mutation of OsPRDA1. Moreover, OsPRDA1 interacts with OsFSD2, a member of PEP-associated proteins (PAPs). Knockout of OsFSD2 leads to the albino and seedling-lethal phenotype and downregulation of PEP-dependent chloroplast genes. Together, our results demonstrated that OsPRDA1 plays essential roles in rice chloroplast development, probably by facilitating the function of the PAP complex and chloroplast gene expression.
叶绿体对于光合作用至关重要，其发育需要叶绿体基因的正确表达。然而，水稻叶绿体基因表达的调控机制尚未完全阐明。在本研究中，我们获得了一个水稻白化突变体，即白苗致死1（wsl1），其叶绿素含量显著降低，叶绿体超微结构受损。利用Mutmap +分离出致病基因水稻PEP相关发育停滞1（OsPRDA1），并通过基因编辑和互补试验进行了验证。OsPRDA1的表达受光诱导，且OsPRDA1定位于叶绿体中。转录组测序显示，与光合作用相关的基因在wsl1中差异表达。由于OsPRDA1的突变，所检测的质体编码RNA聚合酶（PEP）依赖性叶绿体基因的表达水平下调。此外，OsPRDA1与PEP相关蛋白（PAP）成员之一的OsFSD2相互作用。敲除OsFSD2会导致白化和幼苗致死表型以及PEP依赖性叶绿体基因的下调。总之，我们的结果表明，OsPRDA1可能通过促进PAP复合体的功能和叶绿体基因表达，在水稻叶绿体发育中发挥重要作用。
