Plumeria rubra cv. Acutifolia is a widely planted landscape tree in the subtropics. In this study, the complete chloroplast genome of P. rubra cv. Acutifolia was determined through Illumina sequencing method. The complete chloroplast genome has a length of 153,912 bp, containing a small single-copy region (18,036 bp), a large single-copy region (84,852 bp), and a pair of IR regions (25,512 bp). The chloroplast genome possesses 130 genes, including 85 CDS, 37 tRNA genes and 8 rRNA genes. P. rubra cv. Acutifolia exhibited the closest relationship with P. cubensis in phylogenetic analysis.

Archontophoenix alexandrae, known as king palm, is an important landscape tree for the subtropics and potential sources of dietary fiber. In this study, the complete chloroplast genome of A. alexandrae was determined through Illumina sequencing method. The chloroplast genome was 159,196 bp in length and contained a small single-copy region (17,763 bp), a large single-copy region (87,055 bp) and a pair of IR regions (27,189 bp). 135 genes were determined in the A. alexandrae chloroplast genome, including 86 CDS, 39 tRNA genes, and 8 rRNA genes. Archontophoenix alexandrae showed the closest relationship with Veitchia arecina in the phylogenetic analysis.

Cinnamomum cassia Presl is widely known as an important aroma and medicinal tree species growing in tropical and subtropical regions of Asia. The complete chloroplast genome of C. cassia which is 152,763 bp in length was determined. A total of 126 genes were detected in the chloroplast genome, including 36 tRNA genes, 8 rRNA genes, and 82 CDS. The total number of SSRs in this genome is 157. Phylogenetic analysis of this species based on 51 shared chloroplast CDS is provided. These results will provide useful resources for the study of molecular phylogeny and genetics of C. cassia. Bangladesh J. Bot. 51(1): 51-55, 2022 (March)

Taxillus chinensis (DC.) Danser is an important hemiparasitic medicinal plant whose propagation is severely limited by the desiccation sensitivity of its recalcitrant seeds. Dehydrins (DHNs), which protect plants against dehydration-induced stresses such as salinity, drought, and low temperatures, may play a critical role in protecting recalcitrant seeds. However, the role of DHNs in the seeds of T. chinensis remains unclear. In this study, a differentially expressed gene was identified from the seed transcriptome of T. chinensis and designated TcDHN1. Sequence alignment and phylogenetic analyses revealed that TcDHN1 encodes a dehydrin protein. Heterologous overexpression of TcDHN1 in Arabidopsis did not affect growth under normal conditions. Under salt, drought, and cold stresses, transgenic lines exhibited higher seed germination rates, longer primary roots, and improved seedling growth compared with wild-type (WT) plants. The transgenic lines showed significantly increased activities of antioxidant enzymes, including superoxide dismutase, catalase, and peroxidase. In addition, ectopic overexpression of TcDHN1 in Arabidopsis conferred enhanced tolerance to abiotic stresses compared to WT plants, accompanied by increased expression of the stress-responsive genes Responsive to Desiccation 29A (AtRD29A) and Heat Shock Protein 70-1 (AtHSP70-1). The above results indicate that TcDHN1 confers enhanced tolerance to abiotic stresses. This study provides a functional characterization of an abiotic stress-responsive gene from recalcitrant seeds and identifies a potential genetic resource for molecular breeding. This could potentially improve abiotic stress resistance in T. chinensis and related medicinal plants.