State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China.
National Key Facility for Crop Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
New Phytol. 2021 Mar;229(5):2693-2706. doi: 10.1111/nph.17047. Epub 2020 Dec 19.
Thioredoxins (TRXs) occur in plant chloroplasts as complex disulphide oxidoreductases. Although many biological processes are regulated by thioredoxins, the regulatory mechanism of chloroplast TRXs are largely unknown. Here we report a rice white panicle2 mutant caused by a mutation in the thioredoxin z gene, an orthologue of AtTRX z in Arabidopsis. white panicle2 (wp2) seedlings exhibited a high-temperature-sensitive albinic phenotype. We found that plastid multiple organellar RNA editing factors (MORFs) were the regulatory targets of thioredoxin z. We showed that OsTRX z protein physically interacts with OsMORFs in a redox-dependent manner and that the redox state of a conserved cysteine in the MORF box is essential for MORF-MORF interactions. wp2 and OsTRX z knockout lines show reduced editing efficiencies in many plastidial-encoded genes especially under high-temperature conditions. An Arabidopsis trx z mutant also exhibited significantly reduced chloroplast RNA editing. Our combined results suggest that thioredoxin z regulates chloroplast RNA editing in plants by controlling the redox state of MORFs.
硫氧还蛋白（TRXs）在植物叶绿体中作为复杂的二硫键氧化还原酶存在。尽管许多生物过程受到硫氧还蛋白的调节，但叶绿体 TRX 的调节机制在很大程度上尚不清楚。在这里，我们报告了一个由 thioredoxin z 基因突变引起的水稻白穗 2 突变体，该基因在拟南芥中与 AtTRX z 同源。白穗 2（wp2）幼苗表现出高温敏感的白化表型。我们发现，质体多细胞器 RNA 编辑因子（MORFs）是 thioredoxin z 的调节靶标。我们表明，OsTRX z 蛋白以依赖于氧化还原的方式与 OsMORFs 发生物理相互作用，并且 MORF 盒中保守半胱氨酸的氧化还原状态对于 MORF-MORF 相互作用至关重要。wp2 和 OsTRX z 敲除系在许多质体编码基因中的编辑效率降低，特别是在高温条件下。拟南芥 trx z 突变体也表现出明显降低的叶绿体 RNA 编辑。我们的综合结果表明，硫氧还蛋白 z 通过控制 MORFs 的氧化还原状态来调节植物的叶绿体 RNA 编辑。
