Complete chloroplast genomes provide insights into evolution and phylogeny of Zingiber (Zingiberaceae).

The genus Zingiber of the Zingiberaceae is distributed in tropical, subtropical, and in Far East Asia. This genus contains about 100-150 species, with many species valued as important agricultural, medicinal and horticultural resources. However, genomic resources and suitable molecular markers for species identification are currently sparse. We conducted comparative genomics and phylogenetic analyses on Zingiber species. The Zingiber chloroplast genome (size range 162,507-163,711 bp) possess typical quadripartite structures that consist of a large single copy (LSC, 86,986-88,200 bp), a small single copy (SSC, 15,498-15,891 bp) and a pair of inverted repeats (IRs, 29,765-29,934 bp). The genomes contain 113 unique genes, including 79 protein coding genes, 30 tRNA and 4 rRNA genes. The genome structures, gene contents, amino acid frequencies, codon usage patterns, RNA editing sites, simple sequence repeats and long repeats are conservative in the genomes of Zingiber. The analysis of sequence divergence indicates that the following genes undergo positive selection (ccsA, ndhA, ndhB, petD, psbA, psbB, psbC, rbcL, rpl12, rpl20, rpl23, rpl33, rpoC2, rps7, rps12 and ycf3). Eight highly variable regions are identified including seven intergenic regions (petA-pabJ, rbcL-accD, rpl32-trnL-UAG, rps16-trnQ-UUG, trnC-GCA-psbM, psbC-trnS-UGA and ndhF-rpl32) and one genic regions (ycf1). The phylogenetic analysis revealed that the sect. Zingiber was sister to sect. Cryptanthium rather than sect. Pleuranthesis. This study reports 14 complete chloroplast genomes of Zingiber species. Overall, this study provided a solid backbone phylogeny of Zingiber. The polymorphisms we have uncovered in the sequencing of the genome offer a rare possibility (for Zingiber) of the generation of DNA markers. These results provide a foundation for future studies that seek to understand the molecular evolutionary dynamics or individual population variation in the genus Zingiber.

Jiang D ，Cai X ，Gong M ，Xia M ，Xing H ，Dong S ，Tian S ，Li J ，Lin J ，Liu Y ，Li HL ... -  《BMC GENOMICS》

Molecular evolution of chloroplast genomes in subfamily Zingiberoideae (Zingiberaceae).

Zingiberoideae is a large and diverse subfamily of the family Zingiberaceae. Four genera in subfamily Zingiberoideae each possess 50 or more species, including Globba (100), Hedychium (> 80), Kaempferia (50) and Zingiber (150). Despite the agricultural, medicinal and horticultural importance of these species, genomic resources and suitable molecular markers for them are currently sparse. Here, we have sequenced, assembled and analyzed ten complete chloroplast genomes from nine species of subfamily Zingiberoideae: Globba lancangensis, Globba marantina, Globba multiflora, Globba schomburgkii, Globba schomburgkii var. angustata, Hedychium coccineum, Hedychium neocarneum, Kaempferia rotunda 'Red Leaf', Kaempferia rotunda 'Silver Diamonds' and Zingiber recurvatum. These ten chloroplast genomes (size range 162,630-163,968 bp) possess typical quadripartite structures that consist of a large single copy (LSC, 87,172-88,632 bp), a small single copy (SSC, 15,393-15,917 bp) and a pair of inverted repeats (IRs, 29,673-29,833 bp). The genomes contain 111-113 different genes, including 79 protein coding genes, 28-30 tRNAs and 4 rRNA genes. The dynamics of the genome structures, gene contents, amino acid frequencies, codon usage patterns, RNA editing sites, simple sequence repeats and long repeats exhibit similarities, with slight differences observed among the ten genomes. Further comparative analysis of seventeen related Zingiberoideae species, 12 divergent hotspots are identified. Positive selection is observed in 14 protein coding genes, including accD, ccsA, ndhA, ndhB, psbJ, rbcL, rpl20, rpoC1, rpoC2, rps12, rps18, ycf1, ycf2 and ycf4. Phylogenetic analyses, based on the complete chloroplast-derived single-nucleotide polymorphism data, strongly support that Globba, Hedychium, and Curcuma I + "the Kaempferia clade" consisting of Curcuma II, Kaempferia and Zingiber, form a nested evolutionary relationship in subfamily Zingiberoideae. Our study provides detailed information on ten complete Zingiberoideae chloroplast genomes, representing a valuable resource for future studies that seek to understand the molecular evolutionary dynamics in family Zingiberaceae. The identified divergent hotspots can be used for development of molecular markers for phylogenetic inference and species identification among closely related species within four genera of Globba, Hedychium, Kaempferia and Zingiber in subfamily Zingiberoideae.

Li DM ，Li J ，Wang DR ，Xu YC ，Zhu GF ... -  《BMC PLANT BIOLOGY》

Complete chloroplast genomes of Zingiber montanum and Zingiber zerumbet: Genome structure, comparative and phylogenetic analyses.

Li DM ，Ye YJ ，Xu YC ，Liu JM ，Zhu GF ... -  《PLoS One》

Thirteen complete chloroplast genomes of the costaceae family: insights into genome structure, selective pressure and phylogenetic relationships.

Costaceae, commonly known as the spiral ginger family, consists of approximately 120 species distributed in the tropical regions of South America, Africa, and Southeast Asia, of which some species have important ornamental, medicinal and ecological values. Previous studies on the phylogenetic and taxonomic of Costaceae by using nuclear internal transcribed spacer (ITS) and chloroplast genome fragments data had low resolutions. Additionally, the structures, variations and molecular evolution of complete chloroplast genomes in Costaceae still remain unclear. Herein, a total of 13 complete chloroplast genomes of Costaceae including 8 newly sequenced and 5 from the NCBI GenBank database, representing all three distribution regions of this family, were comprehensively analyzed for comparative genomics and phylogenetic relationships. The 13 complete chloroplast genomes of Costaceae possessed typical quadripartite structures with lengths from 166,360 to 168,966 bp, comprising a large single copy (LSC, 90,802 - 92,189 bp), a small single copy (SSC, 18,363 - 20,124 bp) and a pair of inverted repeats (IRs, 27,982 - 29,203 bp). These genomes coded 111 - 113 different genes, including 79 protein-coding genes, 4 rRNA genes and 28 - 30 tRNAs genes. The gene orders, gene contents, amino acid frequencies and codon usage within Costaceae were highly conservative, but several variations in intron loss, long repeats, simple sequence repeats (SSRs) and gene expansion on the IR/SC boundaries were also found among these 13 genomes. Comparative genomics within Costaceae identified five highly divergent regions including ndhF, ycf1-D2, ccsA-ndhD, rps15-ycf1-D2 and rpl16-exon2-rpl16-exon1. Five combined DNA regions (ycf1-D2 + ndhF, ccsA-ndhD + rps15-ycf1-D2, rps15-ycf1-D2 + rpl16-exon2-rpl16-exon1, ccsA-ndhD + rpl16-exon2-rpl16-exon1, and ccsA-ndhD + rps15-ycf1-D2 + rpl16-exon2-rpl16-exon1) could be used as potential markers for future phylogenetic analyses and species identification in Costaceae. Positive selection was found in eight protein-coding genes, including cemA, clpP, ndhA, ndhF, petB, psbD, rps12 and ycf1. Maximum likelihood and Bayesian phylogenetic trees using chloroplast genome sequences consistently revealed identical tree topologies with high supports between species of Costaceae. Three clades were divided within Costaceae, including the Asian clade, Costus clade and South American clade. Tapeinochilos was a sister of Hellenia, and Parahellenia was a sister to the cluster of Tapeinochilos + Hellenia with strong support in the Asian clade. The results of molecular dating showed that the crown age of Costaceae was about 30.5 Mya (95% HPD: 14.9 - 49.3 Mya), and then started to diverge into the Costus clade and Asian clade around 23.8 Mya (95% HPD: 10.1 - 41.5 Mya). The Asian clade diverged into Hellenia and Parahellenia at approximately 10.7 Mya (95% HPD: 3.5 - 25.1 Mya). The complete chloroplast genomes can resolve the phylogenetic relationships of Costaceae and provide new insights into genome structures, variations and evolution. The identified DNA divergent regions would be useful for species identification and phylogenetic inference in Costaceae.

Li DM ，Pan YG ，Liu HL ，Yu B ，Huang D ，Zhu GF ... -  《BMC GENOMICS》

Characterization of the complete chloroplast genome sequences of six Dalbergia species and its comparative analysis in the subfamily of Papilionoideae (Fabaceae).

Array

Li C ，Liu Y ，Lin F ，Zheng Y ，Huang P ... -  《PeerJ》