Complete Chloroplast Genome of and Comparative Analysis with Its Congeneric Invasive Weed .

is considered the closest relative to the invasive weed in China, making it an important native species for studying the invasive mechanisms and adaptations of . Chloroplasts play a crucial role in a plant's environmental adaptation, with their genomes being pivotal in the evolution and adaptation of both invasive and related species. However, the chloroplast genome of has remained unknown until now. In this study, we sequenced and assembled the complete chloroplast genome of using high-throughput sequencing. The chloroplast genome is 151,935 base pairs long, comprising two inverted repeat regions, a large single copy region, and a small single copy region. This chloroplast genome contains 128 genes, including 8 rRNA-coding genes, 37 tRNA-coding genes, 4 pseudogenes, and 83 protein-coding genes. When compared to the chloroplast genome of the invasive weed and other Amaranthaceae species, we observed significant variations in the , , and regions in the chloroplast genome. Moreover, two genes, and , were found to be undergoing rapid evolution due to positive selection pressure. The phylogenetic trees were constructed for the Amaranthaceae family, estimating the time of independent species formation between and to be approximately 3.5186-8.8242 million years ago. These findings provide a foundation for understanding the population variation within invasive species among the genus.