Comparative Analysis of Chloroplast Genomes in and Its Related Genus (): Insights into Adaptive Evolution.

species are well-known as plant pathogens that cause red rust or algae spot diseases in many economically cultivated plants that grow in shady and humid environments. Despite their prevalence, the adaptive evolution of these pathogens remains poorly understood. We sequenced and characterized three (, , and ) chloroplast genomes, and compared them with seven previously reported chloroplast genomes. The chloroplast sequences of , , and were 480,613 bp, 383,846 bp, and 472,444 bp in length, respectively. These chloroplast genomes encoded 94 genes, including 27 tRNA genes, 3 rRNA genes, and 64 protein-coding genes. Comparative analysis uncovered that the variation in genome size was principally due to the length of intergenic spacer sequences, followed by introns. Furthermore, several highly variable regions (, , , , , , , , , , , , and ) were identified. Codon bias analysis revealed that the codon usage pattern of is predominantly shaped by natural selection. Additionally, six chloroplast protein-coding genes (, , , , , and ) were determined to be under positive selection, suggesting they may play a vital roles in the adaptation of to low-light intensity habitats.