The Complete Chloroplast Genome of An Ophiorrhiza baviensis Drake Species Reveals Its Molecular Structure, Comparative, and Phylogenetic Relationships.

Ophiorrhiza baviensis Drake, a flowering medical plant in the Rubiaceae, exists uncertainly within the Ophiorrhiza genus' evolutionary relationships. For the first time, the whole chloroplast (cp) genome of an O. baviensis Drake species was sequenced and annotated. Our findings demonstrate that the complete cp genome of O. baviensis is 154,770 bp in size, encoding a total of 128 genes, including 87 protein-coding genes, 8 rRNAs, and 33 tRNAs. A total of 59 SSRs were screened in the studied cp genome, along with six highly variable loci, which can be applied to generate significant molecular markers for the Ophiorrhiza genus. The comparative analysis of the O. baviensis cp genome with two published others of the Ophiorrhiza genus revealed a high similarity; however, there were some notable gene rearrangements in the O. densa plastome. The maximum likelihood phylogenetic trees were constructed based on the concatenation of the rps16 gene and the trnL-trnF intergenic spacer sequence, indicating a close relationship between the studied O. baviensis and other Ophiorrhiza. This study will provide a theoretical molecular basis for identifying O. baviensis Drake, as well as species of the Ophiorrhiza genus, and contribute to shedding light on the chloroplast genome evolution of Rubiaceae.

Complete chloroplast genome of novel Adrinandra megaphylla Hu species: molecular structure, comparative and phylogenetic analysis.

Adrinandra megaphylla Hu is a medicinal plant belonging to the Adrinandra genus, which is well-known for its potential health benefits due to its bioactive compounds. This study aimed to assemble and annotate the chloroplast genome of A. megaphylla as well as compare it with previously published cp genomes within the Adrinandra genus. The chloroplast genome was reconstructed using de novo and reference-based assembly of paired-end reads generated by long-read sequencing of total genomic DNA. The size of the chloroplast genome was 156,298 bp, comprised a large single-copy (LSC) region of 85,688 bp, a small single-copy (SSC) region of 18,424 bp, and a pair of inverted repeats (IRa and IRb) of 26,093 bp each; and a total of 51 SSRs and 48 repeat structures were detected. The chloroplast genome includes a total of 131 functional genes, containing 86 protein-coding genes, 37 transfer RNA genes, and 8 ribosomal RNA genes. The A. megaphylla chloroplast genome indicated that gene content and structure are highly conserved. The phylogenetic reconstruction using complete cp sequences, matK and trnL genes from Pentaphylacaceae species exhibited a genetic relationship. Among them, matK sequence is a better candidate for phylogenetic resolution. This study is the first report for the chloroplast genome of the A. megaphylla.