Comparative Genomics of Eight Complete Chloroplast Genomes of Phyllostachys Species

Abstract

(1) Background: The genus Phyllostachys belongs to the subfamily Bambusoideae within the family Gramineae. Bamboos of this genus are distinguished by their remarkable genetic traits, including exceptional resistance to both cold and drought conditions. These species possess considerable economic, ecological, and aesthetic value, finding extensive use in forestry and landscape design across China. (2) Methods: This study employed Illumina’s second-generation sequencing technology to sequence the chloroplast genomes of eight Phyllostachys species, followed by their assembly and annotation. (3) Results: The chloroplast genomes of the genus exhibit a characteristic tetrad structure with an average sequence length of 139,699 bp and an average GC content of 38.9%. A total of 130 genes have been annotated across eight bamboo species, comprising 75 protein-coding genes, 28 tRNA genes, and four rRNA genes. Global alignment and nucleotide polymorphism analyses indicate that the chloroplast genome of Phyllostachys is highly conserved overall. The boundaries of the four chloroplast regions are relatively conserved and exhibit minimal differences. Among these regions, three coding region genes—atpH, trnQ-UUG, and petB—and five non-coding regions—rpl32-trnL-UAG, rpl14-rpl16, rpl22-rps19, rps12-clpP, and trnR-UCU-trnM-CAU—exhibit high polymorphism and can be used as potential hotspot areas for subsequent research. A total of 266 simple sequence repeat (SSR) loci were identified by SSR analysis in the chloroplast genomes of eight bamboo species; the largest number of mononucleotide repeats was 154, predominantly consisting of A/T. Codon bias in the chloroplast genomes of the eight bamboo species indicates a preference for codons ending with A and U. Additionally, the UUA codon, which encodes leucine (Leu), is positioned between codons encoding phenylalanine (Phe), lysine (Lys), leucine (Leu), serine (Ser), and tyrosine (Tyr), indicating certain differences among these species. (4) Conclusions: This study aims to offer novel insights into the population genetics, phylogenetic relationships, and evolutionary patterns of Phyllostachys.