Transcription termination factor required for processing and steady-state levels of plastid transcripts (PubMed:22905186). Involved also in chloroplast transcriptional pausing, a general feature of chloroplast genes (PubMed:31128276). Specifically and positively regulates the transcription of chloroplast psbEFLJ encoding for photosystem II (PSII) core subunits psbE, psbF, psbL and psbJ; causes the plastid-encoded RNA polymerase (PEP) complex to pause at psbEFLJ by binding to the +30 to +51 region of double-stranded DNA, and recruits additional pTAC6 to the transcriptionally paused region of psbEFLJ (PubMed:31128276). May play a role in response to abiotic stresses (PubMed:22905186). Interacts with pTAC6. Expressed in roots, rosette leaves, cauline leaves, stems, flower buds and open flowers. Pale-green phenotype, reduced growth and altered structure of chloroplasts (PubMed:22905186, PubMed:31128276). Defect in photosystem II (PSII) function with strongly reduced levels of core subunits, including psbE, psbF, psbL and psbJ cotranscribed from psbEFLJ (PubMed:31128276). Enhanced osmotic stress tolerance and altered sugar responses during seedling establishment (PubMed:22905186). Belongs to the mTERF family.