The first complete chloroplast genome of Hedychium coronarium (Zingiberaceae) was reported in this study. The H. coronarium chloroplast genome was 163,949 bp in length and comprised a pair of inverted repeat (IR) regions of 29,780 bp each, a large single-copy (LSC) region of 88,581 bp and a small single-copy (SSC) region of 15,808 bp. It encoded 141 genes, including 87 protein-coding genes (79 PCG species), 46 tRNA genes (28 tRNA species), and eight rRNA genes (four rRNA species). The nucleotide composition was asymmetric (31.68% A, 18.35% C, 17.74% G, 32.23% T) with an overall AT content of 63.92%. Phylogenetic analysis showed that H. coronarium was classified into a monophyletic group within the genus Hedychium in family Zingiberaceae.

Curcuma longa , a well-known traditional medicinal plant in China, belongs to the genus Curcuma family Zingiberaceae. In this study, we firstly assembled the complete chloroplast genome of C. longa based on sequences from Illumina and PacBio sequencing platforms. We obtained the complete chloroplast genome with the total length of 162,176 bp. It consisted of a large single-copy region (LSC, 86,984 bp), a small single-copy region (SSC, 15,694 bp), and a pair of inverted repeats (IRs, 29,749 bp each). Sequence analyses indicated that the chloroplast genome contained 111 distinct genes including 79 protein-coding genes, 28 tRNA genes, and four rRNA genes. The nucleotide composition was asymmetric (31.62% A, 18.42% C, 17.79% G, 32.18% T) with an overall AT content of 63.80%. The AT contents of the LSC, SSC and IR regions were 66.00%, 70.35% and 58.85%, respectively. Sixteen genes owned a single intron, while another two genes had two introns. The phylogenetic analysis indicated that C. longa was closely related to species Curcuma roscoeana within the genus Curcuma in family Zingiberaceae.

Aglaonema, commonly called Chinese evergreens, are widely used for ornamental purposes. However, attempts to identify Aglaonema species and cultivars based on leaf morphology have been challenging. In the present study, chloroplast sequences were used to elucidate the phylogenetic relationships of cultivated Aglaonema in South China. The chloroplast genomes of one green species and five variegated cultivars of Aglaonema, Aglaonema modestum, ‘Red Valentine’, ‘Lady Valentine’, ‘Hong Yan’, ‘Hong Jian’, and ‘Red Vein’, were sequenced for comparative and phylogenetic analyses. The six chloroplast genomes of Aglaonema had typical quadripartite structures, comprising a large single copy (LSC) region (91,092–91,769 bp), a small single copy (SSC) region (20,816–26,501 bp), and a pair of inverted repeat (IR) regions (21,703–26,732 bp). The genomes contained 112 different genes, including 79–80 protein coding genes, 28–29 tRNAs and 4 rRNAs. The molecular structure, gene order, content, codon usage, long repeats, and simple sequence repeats (SSRs) were generally conserved among the six sequenced genomes, but the IR-SSC boundary regions were significantly different, and ‘Red Vein’ had a distinct long repeat number and type frequency. For comparative and phylogenetic analyses, Aglaonema costatum was included; it was obtained from the GenBank database. Single-nucleotide polymorphisms (SNPs) and insertions/deletions (indels) were determined among the seven Aglaonema genomes studied. Nine divergent hotspots were identified: trnH-GUG-CDS1_psbA, trnS-GCU_trnS-CGA-CDS1, rps4-trnT-UGU, trnF-GAA-ndhJ, petD-CDS2-rpoA, ycf1-ndhF, rps15-ycf1-D2, ccsA-ndhD, and trnY-GUA-trnE-UUC. Additionally, positive selection was found for rpl2, rps2, rps3, ycf1 and ycf2 based on the analyses of Ka/Ks ratios among 16 Araceae chloroplast genomes. The phylogenetic tree based on whole chloroplast genomes strongly supported monophyletic Aglaonema and clear relationships among Aroideae, Lasioideae, Lemnoideae, Monsteroideae, Orontioideae, Pothoideae and Zamioculcadoideae in the family Araceae. By contrast, protein coding gene phylogenies were poorly to strongly supported and incongruent with the whole chloroplast genome phylogenetic tree. This study provided valuable genome resources and helped identify Aglaonema species and cultivars.

The first complete chloroplast genome of Curcuma zedoaria (Zingiberaceae) was reported in this study. The C. zedoaria chloroplast genome was 162,135 bp in length, and consisted of one large single-copy (LSC) region of 86,966 bp, one small single-copy (SSC) region of 15,737 bp, and a pair of inverted repeat (IR) regions 29,716 bp. It encoded 141 genes, including 87 protein-coding genes (79 PCG species), 46 tRNA genes (28 tRNA species), and 8 rRNA genes (4 rRNA species). The phylogenetic analysis based on single nucleotide polymorphisms strongly supported that C. zedoaria, Curcuma roscoeana, Curcuma longa, and Stahlianthus involucratus clustered together in group Curcuma II within the family Zingiberaceae.