CLB19, a pentatricopeptide repeat protein required for editing ofrpoAandclpPchloroplast transcripts

onsejo Nacional de Ciencia y Tecnologia 31791-N Direccion General de Asuntos para el Personal Academico-UNAM IN218007 French Ministry of Education and Research French Australian ST (FAST) FR060030 Australian Research Council CE0561495International audienceRNA editing changes the sequence of many transcripts in plant organelles, but little is known about the molecular mechanisms determining the specificity of the process. In this study, we have characterized CLB19 (also known as PDE247), a gene that is required for editing of two distinct chloroplast transcripts, rpoA and clpP. Loss-of-function clb19 mutants present a yellow phenotype with impaired chloroplast development and early seedling lethality under greenhouse conditions. Transcript patterns are profoundly affected in the mutant plants, with a pattern entirely consistent with a defect in activity of the plastid-encoded RNA polymerase. CLB19 encodes a pentatricopeptide repeat protein similar to the editing specificity factors CRR4 and CRR21, but, unlike them, is implicated in editing of two target sites