GhCTEF2 encodes a PLS-type PPR protein required for chloroplast development and plastid RNA editing in cotton

Abstract

Cotton is a significant cash crop and serves as a crucial raw material for the textile industry. The leaf, which is the site of photosynthesis in cotton plants, directly influences their growth and yield. Pentatricopeptide repeat (PPR) proteins are characterized by tandem 30–40 amino acid motifs. These proteins play a pivotal role in post-transcriptional regulation of organelle gene expression. In this study, we identified GhCTEF2 as a PLS-type PPR protein and determined its subcellular localization within chloroplasts, highlighting its essential involvement in chloroplast development. Virus-induced gene silencing assays revealed that knockdown of the GhCTEF2 gene resulted in macular phenotypes on cotton leaves and significantly reduced photosynthetic efficiency. Additionally, GhCTEF2-silenced plants exhibited incomplete chloroplasts with reduced thylakoids and grana structures. Furthermore, our findings showed that the downregulation of GhCTEF2 reduced the transcription levels of PEP-dependent genes and significantly decreased the content of the chloroplast LHCⅡ-T complex protein. Further studies showed that GhCTEF2 may interact with other editing factors to regulate the RNA editing process of ndhB, accD, and rps18. These findings offer valuable insights into future breeding strategies aimed at enhancing photosynthesis in cotton.