Nuclear-encoded maturase required for splicing of group-II introns in mitochondria. Involved in the splicing of mitochondrial COX2, NAD1 and NAD7 transcripts (PubMed:19946041). Necessary for mitochondrial biogenesis during early developmental stages (PubMed:22429648). Associated to a large ribonucleoprotein complex in mitochondria containing group-II intron RNAs. Low germination, slow growth, and late flowering, as well as partial sterile of both male and female gametes. Small, pale and round-shaped leaves. Impaired splicing of mitochondrial group-II introns-containing COX2, NAD1 and NAD7 transcripts (PubMed:19946041). Abnormal mitochondrial mor-phology, including low-density cristae (PubMed:22429648). Belongs to the plant nuclear intron maturase (nMat) family. Truncated N-terminus.