Organization and comparative analysis of the multi-chromosomal mitochondrial genome in Tagetes erecta (Asteraceae)

Tagetes erecta, commonly known as marigold, is a vibrant-flowered plant native to Mexico and Central America, widely appreciated for its striking golden-yellow or orange blossoms and diverse applications in traditional medicine. Despite its significance, the mitochondrial genome of T. erecta has not been thoroughly characterized, leaving a gap in understanding genomic variation within the Asteraceae family. In this study, we sequenced and assembled the mitochondrial genome (mitogenome) of T. erecta, revealing five independent circular chromosomes with a total length of 259,855 bp and an average GC content of 44.81%. Repeat analysis identified 104 SSRs, 22 tandem repeats, and 83 dispersed repeats in T. erecta mitogenome. We identified nine mitochondrial plastid DNA sequences (MTPTs) ranging from 33 to 771 bp, which included complete plastid gene sequences and partial plastid protein-coding genes (PCGs). Phylogenetic analysis of 40 Asteraceae species indicated that T. erecta was clustered within Heliantheae alliance. Additionally, 573 RNA editing sites were identified across 30 PCGs based on RNA-seq data. These findings provide new mitochondrial genomic resources that enhance our understanding of the evolution and genomic variation in Asteraceae, offering insights that may benefit breeding processes and resource conservation efforts.