To expand the genomic information of Hypericaceae, particularly on Cratoxylum, we characterized seven novel complete plastid genomes (plastomes) of five Cratoxylum and two of its allied taxa, including C. arborescens, C. formosum subsp. formosum, C. formosum subsp. pruniflorum, C. maingayi, C. sumatranum, Hypericum hookerianum, and Triadenum breviflorum. For Cratoxylum, the plastomes ranged from 156,962 to 157,792 bp in length. Genomic structure and gene contents were observed in the five plastomes, and were comprised of 128-129 genes, which includes 83-84 protein-coding (CDS), 37 tRNA, and eight rRNA genes. The plastomes of H. hookerianum and T. breviflorum were 138,260 bp and 167,693 bp, respectively. A total of 110 and 127 genes included 72 and 82 CDS, 34 and 37 tRNA, as well as four and eight rRNA genes. The reconstruction of the phylogenetic trees using maximum likelihood (ML) and Bayesian inference (BI) trees based on the concatenated CDS and internal transcribed spacer (ITS) sequences that were analyzed separately have revealed the same topology structure at genus level; Cratoxylum is monophyletic. However, C. formosum subsp. pruniflorum was not clustered together with its origin, raising doubt that it should be treated as a distinct species, C. pruniflorum based on molecular evidence that was supported by morphological descriptions.
Significant past, present, and potential future research into the organellar (plastid and mitochondrial) genomes of gymnosperms that can provide insight into the unknown origin and evolution of plants is highlighted. Gymnosperms are vascular seed plants that predominated the ancient world before their sister clade, angiosperms, took over during the Late Cretaceous. The divergence of gymnosperms and angiosperms took place around 300 Mya, with the latter evolving into the diverse group of flowering plants that dominate the plant kingdom today. Although gymnosperms have reportedly made some evolutionary innovations, the literature on their genome advances, particularly their organellar (plastid and mitochondrial) genomes, is relatively scattered and fragmented. While organellar genomes can shed light on plant origin and evolution, they are frequently overlooked, due in part to their limited contribution to gene expression and lack of evolutionary dynamics when compared to nuclear genomes. A better understanding of gymnosperm organellar genomes is critical because they reveal genetic changes that have contributed to their unique adaptations and ecological success, potentially aiding in plant survival, enhancement, and biodiversity conservation in the face of climate change. This review reveals significant information and gaps in the existing knowledge base of organellar genomes in gymnosperms, as well as the challenges and research needed to unravel their complexity.
Gigantochloa verticillata is produced in Mengla and Jinghong, Yunnan Province, China, and cultivated in Hong Kong. Vietnam, Thailand, India, Indonesia, and Malaysia are distributed and cultivated. We determined the complete chloroplast genome sequence for G. verticillata using Illumina sequencing data. The complete chloroplast sequence is 139,489 bp, including large single-copy (LSC) region of 83,062 bp, small single-copy (SSC) region of 12,877 bp, and a pair of invert repeats (IR) regions of 21,775 bp. Plastid genome contain 132 genes, 85 protein-coding genes, 39 tRNA genes, and 8 rRNA genes. Phylogenetic analysis based on 23 chloroplast genomes indicates that G. verticillata is closely related to Dendrocalamus latiflorus in Bambusodae.