Characterization and comparative analysis of the complete mitochondrial genomes of two Amorphophallus species (Araceae)

Abstract

Amorphophallus muelleri and Amorphophallus krausei are perennial herbaceous plants of the genus Amorphophallus (family Araceae). Their tubers can be processed into food and possess medicinal and economic value. However, their mitochondrial genomes have not yet been reported. Therefore, this study sequenced, assembled, and annotated the mitochondrial genomes of A. muelleri and A. krausei and conducted a comparative phylogenetic analysis with closely related species. The results indicated that the mitochondrial genomes of A. muelleri and A. krausei are circular molecules, with lengths of 592,591 bp and 593,535 bp, and GC contents of 45.90% and 46.05%, respectively. They contain 59 and 62 genes, respectively, with 55 genes being common to both species. The study identified 28 high-frequency codons (RSCU > 1) in the mitochondrial genomes of both species. Furthermore, 91 and 125 dispersed repeats, 141 and 148 simple sequence repeats (SSRs), and 43 and 220 RNA editing sites were identified in A. muelleri and A. krausei, respectively. Analysis of the coding sequences from the mitochondrial genomes of eight Araceae species identified 33 shared sequences. The Ka/Ks ratios for most shared protein-coding genes were less than 1, indicating that these genes have undergone purifying selection during evolution, and their protein functions are relatively conserved. The phylogenetic tree showed that A. muelleri is closely related to A. krausei and A. albus. Overall, this study provides valuable genetic resources for the genus Amorphophallus and will facilitate further research on the molecular diversity and genetic evolution of A. muelleri and A. krausei. Amorphophallus tubers are rich in glucomannan, a valuable dietary fiber, yet the mitochondrial genomes of these plants remained unexplored. This study sequenced and compared the complete mitochondrial DNA ofAmorphophallus muelleri and Amorphophallus krausei. The analysis uncovered large, circular genomes and revealed that most essential genes have undergone purifying selection, meaning evolution has preserved their function. Unique genetic markers were also identified. These newly assembled mitochondrial blueprints provide a vital foundation for future research into the evolution, diversity, and cultivation of these glucomannan-producing plants.