Mazusjiangshiense (Mazaceae), a new species from China: evidence from morphological and molecular analyses.

Utilising both morphological and molecular analyses, this study unveils Mazusjiangshiensesp. nov., a novel addition to the Mazaceae family, discovered in Shaowu County, Fujian Province, China. The comprehensive description and illustrations provided here are a result of a meticulous exploration of its morphological features. While bearing a resemblance to M.gracilis, this new-found species is distinguished by three distinct characteristics: its stems are delicately soft, its leaves possess a membranous quality and the ovary is notably villous at the apex. Integration of molecular evidence, derived from the nuclear ribosomal DNA (nrITS) and three plastid DNA sequences (rps16, rbcL and trnL-trnF), unequivocally supports the classification of M.jiangshiense as a distinct species. Notably, the molecular analysis positions it as a sister species to M.spicatus, underscoring the phylogenetic relationships within the genus Mazus. Our research not only introduces M.jiangshiense as a novel taxonomic entity, but also provides a nuanced understanding of its morphological differences and molecular affinities, enriching our comprehension of the diversity and evolutionary relationships of Mazaceae.

Comparative Analysis of Six Complete Plastomes of Tripterospermum spp.

The Tripterospermum, comprising 34 species, is a genus of Gentianaceae. Members of Tripterospermum are mostly perennial, entwined herbs with high medicinal value and rich in iridoids, xanthones, flavonoids, and triterpenes. However, our inadequate understanding of the differences in the plastid genome sequences of Tripterospermum species has severely hindered the study of their evolution and phylogeny. Therefore, we first analyzed the 86 Gentianae plastid genomes to explore the phylogenetic relationships within the Gentianae subfamily where Tripterospermum is located. Then, we analyzed six plastid genomes of Tripterospermum, including two newly sequenced plastid genomes and four previously published plastid genomes, to explore the plastid genomes' evolution and phylogenetic relationships in the genus Tripterospermum. The Tripterospermum plastomes have a quadripartite structure and are between 150,929 and 151,350 bp in size. The plastomes of Tripterospermum encoding 134 genes were detected, including 86 protein-coding genes (CDS), 37 transfer RNA (tRNA) genes, eight ribosomal RNA (rRNA) genes, and three pseudogenes (infA, rps19, and ycf1). The result of the comparison shows that the Tripterospermum plastomes are very conserved, with the total plastome GC content ranging from 37.70% to 37.79%. In repeat sequence analysis, the number of single nucleotide repeats (A/T) varies among the six Tripterospermum species, and the identified main long repeat types are forward and palindromic repeats. The degree of conservation is higher at the SC/IR boundary. The regions with the highest divergence in the CDS and the intergenic region (IGS) are psaI and rrn4.5-rrn5, respectively. The average pi of the CDS and the IGS are only 0.071% and 0.232%, respectively, indicating that the Tripterospermum plastomes are highly conserved. Phylogenetic analysis indicated that Gentianinae is divided into two clades, with Tripterospermum as a sister to Sinogeniana. Phylogenetic trees based on CDS and CDS + IGS combined matrices have strong support in Tripterospermum. These findings contribute to the elucidation of the plastid genome evolution of Tripterospermum and provide a foundation for further exploration and resource utilization within this genus.

Comparative Analysis of Plastomes in Elsholtzieae: Phylogenetic Relationships and Potential Molecular Markers.

The Elsholtzieae, comprising ca. 7 genera and 70 species, is a small tribe of Lamiaceae (mint family). Members of Elsholtzieae are of high medicinal, aromatic, culinary, and ornamentals value. Despite the rich diversity and value of Elsholtzieae, few molecular markers or plastomes are available for phylogenetics. In the present study, we employed high-throughput sequencing to assemble two Mosla plastomes, M. dianthera and M. scabra, for the first time, and compared with other plastomes of Elsholtzieae. The plastomes of Elsholtzieae exhibited a quadripartite structure, ranging in size from 148,288 bp to 152,602 bp. Excepting the absence of the pseudogene rps19 in Elsholtzia densa, the exhaustive tally revealed the presence of 132 genes (113 unique genes). Among these, 85 protein-coding genes (CDS), 37 tRNA genes, 8 rRNA genes, and 2 pseudogenes (rps19 and ycf1) were annotated. Comparative analyses showed that the plastomes of these species have minor variations at the gene level. Notably, the E. eriostchya plastid genome exhibited increased GC content regions in the LSC and SSC, resulting in an increased overall GC content of the entire plastid genome. The E. densa plastid genome displayed modified boundaries due to inverted repeat (IR) contraction. The sequences of CDS and intergenic regions (IGS) with elevated variability were identified as potential molecular markers for taxonomic inquiries within Elsholtzieae. Phylogenetic analysis indicated that four genera formed monophyletic entities, with Mosla and Perilla forming a sister clade. This clade was, in turn, sister to Collinsonia, collectively forming a sister group to Elsholtzia. Both CDS, and CDS + IGS could construct a phylogenetic tree with stronger support. These findings facilitate species identification and DNA barcoding investigations in Elsholtzieae and provide a foundation for further exploration and resource utilization within this tribe.

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In order to understand the interspecific and ecological relationships of Michelia odora (extremely small population) community and strengthen the protection of wild M. odora resources in Junzifeng Nature Reserve, we studied the niche characteristics and interspecific associations of dominant tree species. The results showed that M. odora, Machilus chekiangensis, Schima superba, and Alniphyllum fortunei had obvious niche breadth advantages, which were the constructive species of the community. Among the 190 groups of species pairs among the 20 dominant tree species, 50.5% of species pairs had niche overlap value greater than 0.5. The degree of ecological niche differentiation among species was general. M. odora had large niche overlap with other 19 species, indicating a competitive risk when resources were insufficient. The overall associations of dominant tree species were significantly positive, indicating the community was at the late stage of relatively stable succession. The results ofχ2 test, asso-ciation coefficient, and Pearson correlation coefficient showed that all the significance ratios of interspecific association were lower, and that the independence among species was relatively strong. There was a positive correlation between interspecific association and niche overlap. The M. odora community was relatively mature, with full utilization of resources and stable interspecific relationship. To promote the rejuvenation and create a good habitat of M. odora population, the population size with large overlap with M. odora niche and significant negative association could be appropriately limited, while that with positive interaction could be increased.

Genome-wide identification and analysis of anthocyanin synthesis-related R2R3-MYB genes in Cymbidium goeringii.

The MYB gene family plays a vital regulatory role in plant metabolism, stress response, and floral color. The R2R3-MYB gene family of C. goeringii was identified, and its expression was analyzed using bioinformatics in this article. The R2R3-MYB genes of Arabidopsis thaliana were used as a reference to determine 104 CgMYB genes and categorize them into 22 subfamilies. Exon/intron organizations and conserved motif analysis revealed that the majority of CgMYB genes were highly conserved, and chromosome localization and collinearity analysis provided evidence of tandem duplication and segmental duplication events, indicating the phenomenon of gene family expansion and contraction. The function of CgMYB genes was analyzed by cis-acting element and gene ontology (GO) enrichment. In addition, we selected CgMYB91 and CgMYB32 for RT-qPCR, suggesting that CgMYB91 and CgMYB32 are associated with anthocyanin formation. In short, this study provides a comprehensive and specific function of the R2R3-MYB transcription factors (TFs) in orchids.

Genomes of leafy and leafless Platanthera orchids illuminate the evolution of mycoheterotrophy.

To improve our understanding of the origin and evolution of mycoheterotrophic plants, we here present the chromosome-scale genome assemblies of two sibling orchid species: partially mycoheterotrophic Platanthera zijinensis and holomycoheterotrophic Platanthera guangdongensis. Comparative analysis shows that mycoheterotrophy is associated with increased substitution rates and gene loss, and the deletion of most photoreceptor genes and auxin transporter genes might be linked to the unique phenotypes of fully mycoheterotrophic orchids. Conversely, trehalase genes that catalyse the conversion of trehalose into glucose have expanded in most sequenced orchids, in line with the fact that the germination of orchid non-endosperm seeds needs carbohydrates from fungi during the protocorm stage. We further show that the mature plant of P. guangdongensis, different from photosynthetic orchids, keeps expressing trehalase genes to hijack trehalose from fungi. Therefore, we propose that mycoheterotrophy in mature orchids is a continuation of the protocorm stage by sustaining the expression of trehalase genes. Our results shed light on the molecular mechanism underlying initial, partial and full mycoheterotrophy.

The Cymbidium genome reveals the evolution of unique morphological traits.

The marvelously diverse Orchidaceae constitutes the largest family of angiosperms. The genus Cymbidium in Orchidaceae is well known for its unique vegetation, floral morphology, and flower scent traits. Here, a chromosome-scale assembly of the genome of Cymbidium ensifolium (Jianlan) is presented. Comparative genomic analysis showed that C. ensifolium has experienced two whole-genome duplication (WGD) events, the most recent of which was shared by all orchids, while the older event was the τ event shared by most monocots. The results of MADS-box genes analysis provided support for establishing a unique gene model of orchid flower development regulation, and flower shape mutations in C. ensifolium were shown to be associated with the abnormal expression of MADS-box genes. The most abundant floral scent components identified included methyl jasmonate, acacia alcohol and linalool, and the genes involved in the floral scent component network of C. ensifolium were determined. Furthermore, the decreased expression of photosynthesis-antennae and photosynthesis metabolic pathway genes in leaves was shown to result in colorful striped leaves, while the increased expression of MADS-box genes in leaves led to perianth-like leaves. Our results provide fundamental insights into orchid evolution and diversification.

The complete plastome of Bulbophyllum pingnanense (Orchidaceae: Dendrobiinae).

The complete plastid genome of Bulbophyllum pingnanense, a critically endangered species, was determined and analyzed in this study. The complete genome was 151,224 bp in length, consisting of a large single-copy region (LSC) of 86,017 bp, a small single-copy region (SSC) of 13,497 bp, and two inverted repeat (IR) regions of 25,855 bp. The genome contained 127 genes, including 81 protein-coding genes, 38 transfer RNA (tRNA) genes, and eight ribosomal RNA (rRNA) genes. Phylogenetic analysis indicated that B. pingnanense is sister to B. inconspicuum.

Pseudostellariawuyishanensis, a new species of Caryophyllaceae from Fujian, China.

Pseudostellariawuyishanensis, a new species from the Wuyishan National Park, Fujian, China, is described and illustrated. Morphologically, Pseudostellariawuyishanensis resembles P.heterantha. However, the new species can be distinguished by presence of stolons, 1 line of hairs on the stem, smaller leaf blades, shorter pedicels, and ovary with 2 styles.

Plastid phylogenomics improves resolution of phylogenetic relationship in the Cheirostylis and Goodyera clades of Goodyerinae (Orchidoideae, Orchidaceae).

Goodyerinae are one of phylogenetically unresolved groups of Orchidaceae. The lack of resolution achieved through the analyses of previous molecular sequences from one or a few markers has long confounded phylogenetic estimation and generic delimitation. Here, we present large-scale phylogenomic data to compare the plastome structure of the two main clades (Goodyera and Cheirostylis) in this subtribe and further adopt two strategies, combining plastid coding sequences and the whole plastome, to investigate phylogenetic relationships. A total of 46 species in 16 genera were sampled, including 39 species in 15 genera sequenced in this study. The plastomes of heterotrophic species are not drastically reduced in overall size, but display a pattern congruent with a loss of photosynthetic function. The plastomes of autotrophic species ranged from 147 to 165 kb and encoded from 132 to 137 genes. Three unusual structural features were detected: a 1.0-kb inversion in the large single-copy region of Goodyera schlechtendaliana; the loss and/or pseudogenization of ndh genes only in two species, Cheirostylis chinensis and C. montana; and the expansion of inverted repeat regions and contraction of small single-copy region in Hetaeria oblongifolia. Phylogenomic analyses provided improved resolution for phylogenetic relationships. All genera were recovered as monophyletic, except for Goodyera and Hetaeria, which were each recovered as non-monophyletic. Nomenclatural changes are needed until the broader sampling and biparental inherited markers. This study provides a phylogenetic framework of Goodyerinae and insight into plastome evolution of Orchidaceae.

The complete chloroplast genome sequence of Alniphyllum fortunei (Styracaceae) from Fujian, China.

Alniphyllum fortunei is a subtropical tree species, a large deciduous tree with a tall and straight trunk, which is an excellent fast-growing and broad-leaved tree species with a wide range of uses we resequenced complete chloroplast (cp) genome of A. fortunei from Fujian, China. The whole genome was 154,166 bp in length, consisting of a pair of inverted repeats (IR 26,658 bp), a large single-copy region (LSC 82,438 bp), and a small single-copy region (SSC 18,367 bp). The complete genome contained 139 genes, including 89 protein-coding genes, 40 tRNA, and 8 rRNA genes. The phylogenetic analyses based on the complete chloroplast genome sequence provided solid evidence that A. fortunei has a close relationship with A. pterospermum and Bruinsmia polysperma.

The Phoebe genome sheds light on the evolution of magnoliids.

Lauraceae includes the genus Phoebe, and the family is linked to the evolution of magnoliids. We sequenced the genome of Phoebe bournei Nanmu. The assembled genome size was 989.19 Mb, with a contig N50 value of 2.05 Mb. A total of 28,198 protein-coding genes were annotated in P. bournei. Whole-genome duplication (WGD) analysis showed that Lauraceae has experienced two WGD events; the older WGD event occurred just before the divergence of Lauraceae and Magnoliales, and the more recent WGD was shared by all lineages of Lauraceae. The phylogenetic tree showed that magnoliids form a sister clade to monocots and eudicots. We also identified 63 MADS-box genes, including AGL12-like genes that may be related to the regulation of P. bournei roots and FIN219-like genes encoding GH3 proteins, which are involved in photomorphogenesis. SAUR50-like genes involved in light signal-mediated pedicel or stem development were also identified. Four ATMYB46- and three PtrEPSP-homologous genes related to lignin biosynthesis were identified. These genes may be associated with the formation of straight trunks in P. bournei. Overall, the P. bournei reference genome provides insight into the origin, evolution, and diversification of Phoebe and other magnoliids.

Plastid phylogenomic data yield new and robust insights into the phylogeny of Cleisostoma-Gastrochilus clades (Orchidaceae, Aeridinae).

The Cleisostoma-Gastrochilus clades are among the most speciose and diverse groups of Asian orchids and are a taxonomically problematic group. Phylogenetic relationships among the genera of these clades have remained unresolved with traditional sequences from one or a few markers. We present large-scale phylogenomic data sets, incorporating complete chloroplast genome sequences from 53 species (including 41 species sequenced in this study), to compare plastome structure and to resolve the phylogenetic relationships of these clades. The plastomes of Cleisostoma-Gastrochilus clades possessed the quadripartite structure and plastome genes of typical angiosperms with sizes ranging from 142 to 149 kb and encoding a set of 118-120 genes. Unusual structural features were detected in the plastome of Uncifera acuminata, including the presence of a large 17-kb inversion (19 genes) in the Large Single-Copy region and the loss of the rpl32 gene in Cleisostoma fuerstenbergianum. The pseudogenization of ndh genes was widespread in these clades. Phylogenomic analyses, including 68 plastid protein-coding genes, showed that these clades can be subdivided into three major groupings and six subgroupings: Vandopsis undulata, the Gastrochilus clade (including the Trichoglottis and Gastrochilus subclades) and the Cleisostoma clade (including the Vandopsis, Diploprora, Cleisostoma and Schoenorchis subclades). Two genera, Vandopsis and Cleisostoma, were not monophyletic. A new genus, Cymbilabia, was proposed to avoid non-monophyly of Vandopsis. Our results demonstrate the power of plastid phylogenomics to improve the phylogenetic relationships of intricate groups and provide new insight into plastome evolution in Orchidaceae.

The complete chloroplast genome sequence of Acorus tatarinowii (Araceae) from Fujian, China.

Acorus tatarinowii is a useful traditional Chinese medicine (TCM) and is officially documented in the Chinese Pharmacopeia with the name 'Shi Chang Pu'. It belongs to the Araceae family and is used for the treatment of dementia, epilepsy, amnesia and insomnia. We resequenced complete chloroplast (cp) genome of A. tatarinowii from Fujian, China. The whole genome was 153,453 bp in length, consisting of a pair of inverted repeats (IR 25,795 bp), a large single-copy region (LSC 83,631 bp), and a small single-copy region (SSC 18,232 bp). The complete genome contained 132 genes, including 84 protein-coding genes, 38 tRNA, and 8 rRNA genes. The overall GC content of the whole genome was 38.7%. A maximum-likelihood phylogenetic analysis showed that A. tatarinowii is sister to A. tatarinowii which was collected in Yunnan, China. The complete chloroplast genome of A. tatarinowii will help improve and integrate the existing genome data of monocots and provide insights into the phylogenetic relationship among basal angiosperms, monocots and dicots.

Molecular systematics of Goodyerinae (Cranichideae, Orchidoideae, Orchidaceae) based on multiple nuclear and plastid regions.

Goodyerinae are one of the most species-rich and widespread subtribes of Orchidaceae but notorious for their taxonomic difficulty. Here, a comprehensive molecular phylogenetic study of the subtribe is presented based on two nuclear (ITS, Xdh) and five plastid (matK, psaB, rbcL, trnL, trnL-F) regions. A total of 119 species were included representing all clades recovered by previous phylogenetic analyses as well as seven outgroups. Maximum parsimony, maximum likelihood and Bayesian inference methods were used to infer the phylogenetic relationships. The results show that the Goodyerinae subdivided into three major subdivisions and six groupings: Pachyplectron, Goodyera clade (including Goodyera procera, Microchilus subclade and Goodyera subclade) and Cheirostylis clade (including Gonatostylis, Cheirostylis subclade and Ludisia subclade). Four genera, Erythrodes, Goodyera, Myrmechis and Odontochilus, are not monophyletic. The results support Odontochilus s. l. to include Myrmechis and Kuhlhasseltia. The systematic positions of Goodyera procera and two isolated genera, Herpysma and Orchipedum, are difficult to determine.

Complete chloroplast genome of Cymbidium ensifolium（Orchidaceae）.

Cymbidium ensifolium is one of the most economical and ornamental significant orchids. It's facing serious genetic resources loss and habitat fragmentation. A conservation strategy is therefore imperative for this endangered orchid. Here, we report on the first complete chloroplast (cp) genome of C. ensifolium. Its full-length of 150,257 bp include large single-copy (LSC) region of 85,110 bp, small single-copy (SSC) region of 13,761 bp, and a pair of invert repeats (IR) regions of 25,692 bp. Plastid genome contain 137 genes, 78 protein-coding genes, 38 tRNA genes, and 8 rRNA genes. Cymbidium ensifolium was sister to C. sinense, Cy. Tortisepalum, and C. kanran. The cp genome will help for further research and conservation of C. ensifolium.

The complete chloroplast genome sequence of Quercus gilva（Fagaceae）.

Quercus gilva is classified as the national second-class protective tree species in China and is widely distributed in Middle East Asia. We determined the complete chloroplast genome sequence for Q. gilva using Illumina sequencing data. The complete chloroplast sequence is 160,763 bp, including large single-copy (LSC) region of 90,292 bp, small single-copy (SSC) region of 18,831 bp, and a pair of invert repeats (IR) regions of 25,820 bp. Plastid genome contains 128 genes, 80 protein-coding genes, 40 tRNA genes, and 8 rRNA genes. Phylogenetic analysis based on 26 chloroplast genomes indicates that Q. gilva is closely related to Q. sichourensis in Fagaceae.

Complete chloroplast genome sequence of bamboo Dendrocalamopsis vario-striata (Gramineae Bambusoideae).

Dendrocalamopsis vario-striata is one of the most economical and ornamental significant bamboo. It has the characteristics of annual flowering but no death. Here, we report on the first complete chloroplast (cp) genome of D. vario-striata. Its full-length of 139,458 bp, include large single-copy (LSC) region of 83,279 bp, small single-copy (SSC) region of 12,143bp, a pair of invert repeats (IR) regions of 22,018bp. Plastid genome contains 264 genes, 170 protein-coding genes, 78 tRNA genes, and 16 rRNA genes. The maximum likelihood phylogenetic analysis shows that D. vario-striata was sister to all other species of Bambusoideae.

The complete chloroplast genome sequence of a Castanea henryi cultivar.

Castanea henryi（Skam）Rehd. et Wils is an important woody plant producing nuts in China. In this study, the complete chloroplast genome sequence of C. henryi was reported by using the Illumina Hiseq 2500 platform. The complete chloroplast sequence is 160,807 bp, including large single-copy (LSC) region of 90,394 bp, small single-copy (SSC) region of 18,963 bp, and a pair of invert repeats (IR) regions of 25,725 bp. Plastid genome contains 112 genes, 78 protein-coding genes, 30 tRNA genes, and 4 rRNA genes. Based on 26 chloroplast genomes, phylogenetic analysis indicates that C. henryi is closely related to C. mollissima in Fagaceae.