Comparative analysis of mitochondrial genome of Corethrodendron scoparium: Insights into structural diversity and evolution of Fabaceae mitogenomes

Corethrodendron scoparium (Fabaceae) is a pioneer desert shrub crucial for wind-breaking and sand-fixing in Central Asia, having substantial ecological and economic value for dryland restoration and bio-resource utilization. However, evolutionary features of C. scoparium mitochondrial genome and structural diversity of Fabaceae mitogenomes remain poorly understood. In this study, a complete mitochondrial genome of C. scoparium was assembled and annotated utilizing PacBio HiFi long-read sequencing, followed by comparative analyses with other Fabaceae mitogenomes. The C. scoparium mitogenome was assembled into a master circular conformation of 421,816 bp, with a GC content of 45.1% and 56 annotated genes. We identified 50 dispersed repeats, 5 tandem repeats, 97 simple sequence repeats, and 438 RNA editing sites, indicating rich genomic complexity and post-transcriptional regulation. Only eight homologous fragments are identified between the mitochondrial and chloroplast genomes of C. scoparium , suggesting limited intracellular gene transfer and evolutionary conservation. Phylogenetic and evolutionary rate analyses showed that C. scoparium is closely related to Caragana spinosa , and most protein-coding genes have undergone purifying selection. Notably, phylogenetic comparative analyses revealed that the size variation and structural diversity of Fabaceae mitogenomes are primarily governed by phylogenetic lineages, with anciently diverged lineages generally possessing larger mitogenomes. These findings provide novel insights into the structural variation and evolution of Fabaceae mitogenomes and crucial genomic resources for the genetic improvement and ecological application of C. scoparium , a key desert shrub in Central Asia.