“…is generally 120-160 kb, with a quadripartite structure involving two inverted repeat (IR) sequences that separate the rest of the genome into large and small single-copy regions (Kwon et al, 2020;Wicke et al, 2011). In particular, conifers are one of the few groups that have lost the canonical IR region (Guo et al, 2014;Kwon et al, 2020;Li et al, 2016;Ping et al, 2020). Compared with nuclear genome and mitochondrion genome, chloroplast genome is characterized by small genome size, high copy number, conservative structure, and moderate nucleotide evolution rate, which has been widely used to understand evolutionary events and to infer efficiently phylogenetic relationships (Barrett et al, 2016;Saina et al, 2018).…”