Attached list

This supplementary table presents the gene lists from the complete chloroplast genomes of three Populus species (P. lasiocarpa, P. gonggaensis, and P. cathayana), including their gene structures, relative synonymous codon usage (RSCU) data, and comparisons with the sequencing results of Dan et al. The chloroplast genomes of the three species exhibit a conserved quadripartite structure, with similar but slightly different gene compositions: P. lasiocarpa contains 130 genes (86 protein-coding genes, 37 tRNA genes, and 7 rRNA genes), while P. gonggaensis and P. cathayana each have 131 genes (86 protein-coding genes, 37 tRNA genes, and 8 rRNA genes), functionally categorized into photosynthesis-related, genetic information transfer-related, and other conserved genes.

Their codon usage patterns are highly similar, with a preference for codons ending in A/U; leucine is the most abundant amino acid, while tryptophan is the least. Compared with the results of Dan et al. (2019), the genome lengths differ by <0.2%, the GC content is consistently 37%, the number of protein-coding genes is identical, and the coding regions show 100% sequence identity. The minor differences in non-coding regions may be attributed to annotation errors or intraspecific heteroplasmy, collectively demonstrating the high conservation and data reliability of chloroplast genomes.