The 'queen of the Andes' (Puya raimondii) is genetically fragile and fragmented: a consequence of long generation time and semelparity?

Understanding how life history shapes genetic diversity is a fundamental issue in evolutionary biology, with important consequences for conservation. However, we still have an incomplete picture of the impact of life history on genome-wide patterns of diversity, especially in long-lived semelparous plants. Puya raimondii is a high-altitude semelparous species from the Andes that flowers at 40-100 years of age. We sequenced the whole genome and estimated the nucleotide diversity of 200 individuals sampled from nine populations. Coalescent-based approaches were then used to infer past population dynamics. Finally, these results were compared with results obtained for the iteroparous species, Puya macrura. The nine populations of P. raimondii were highly divergent, highly inbred, and carried an exceptionally high genetic load. They are genetically depauperate, although, locally in the genome, balancing selection contributed to the maintenance of genetic polymorphism. While both P. raimondii and P. macrura went through a severe bottleneck during the Pleistocene, P. raimondii did not recover from it and continuously declined, while P. macrura managed to bounce back. Our results demonstrate the importance of life history, in particular generation time and reproductive strategy, in affecting population dynamics and genomic variation, and illustrate the genetic fragility of long-lived semelparous plants.

Efficacy of the 'Five-Needle' method for pancreatojejunostomy in laparoscopic pancreaticoduodenectomy: an observational study.

Objective: The five-needle pancreato-intestinal anastomosis method is used in laparoscopic pancreaticoduodenectomy (LPD). The aim of this study was to explore the clinical efficacy and adverse reactions of this new surgical method and to provide a scientific reference for promoting this new surgical method in the future. Methods: A single-centre observational study was conducted to evaluate the safety and practicality of the five-needle method for pancreatojejunostomy in LPD surgeries. The clinical data of 78 patients who were diagnosed with periampullary malignancies and underwent LPD were collected from the 1st of August 2020 to the 31st of June 2023 at Lanzhou University First Hospital. Forty-three patients were treated with the 'Five-Needle' method (test groups), and 35 patients were treated with the 'Duct-to-Mucosa' method (control group) for pancreatojejunostomy. These two methods are the most commonly used and highly preferred pancreatointestinal anastomosis methods worldwide. The primary outcome was pancreatic fistula, and the incidence of which was compared between the two groups. Results: The incidence of pancreatic fistula in the five-needle method group and the duct-to-mucosa method group was not significantly different (25.6% vs. 28.6%, p=0.767). Additionally, there were no significant differences between the two groups in terms of intraoperative blood loss (Z=-1.330, p=0.183), postoperative haemorrhage rates (p=0.998), length of postoperative hospital stay (Z=-0.714, p=0.475), bile leakage rate (p=0.745), or perioperative mortality rate (p=0.999). However, the operative time in the 'Five-Needle' method group was significantly shorter than that in the 'Duct-to-Mucosa' method group (270 ± 170 mins vs. 300 ± 210 mins, Z=-2.336, p=0.019). Further analysis revealed that in patients with pancreatic ducts smaller than 3 mm, the incidence of pancreatic fistula was lower for the 'Five-Needle' method than for the 'Duct-to-Mucosa' method (12.5% vs. 53.8%, p=0.007). Conclusion: The five-needle method is safe and efficient for pancreatojejunostomy in LPD, and is particularly suitable for anastomosis in nondilated pancreatic ducts. It is a promising, valuable, and recommendable surgical method worthy of wider adoption.

Chromosome-level genome assemblies of Musa ornata and Musa velutina provide insights into pericarp dehiscence and anthocyanin biosynthesis in banana.

Musa ornata and Musa velutina are members of the Musaceae family and are indigenous to the South and Southeast Asia. They are very popular in the horticultural market, but the lack of genomic sequencing data and genetic studies has hampered efforts to improve their ornamental value. In this study, we generated the first chromosome-level genome assemblies for both species by utilizing Oxford Nanopore long reads and Hi-C reads. The genomes of M. ornata and M. velutina were assembled into 11 pseudochromosomes with genome sizes of 427.85 Mb and 478.10 Mb, respectively. Repetitive sequences comprised 46.70% and 50.91% of the total genomes for M. ornata and M. velutina, respectively. Differentially expressed gene (DEG) and Gene Ontology (GO) enrichment analyses indicated that upregulated genes in the mature pericarps of M. velutina were mainly associated with the saccharide metabolic processes, particularly at the cell wall and extracellular region. Furthermore, we identified polygalacturonase (PG) genes that exhibited higher expression level in mature pericarps of M. velutina compared to other tissues, potentially being accountable for pericarp dehiscence. This study also identified genes associated with anthocyanin biosynthesis pathway. Taken together, the chromosomal-level genome assemblies of M. ornata and M. velutina provide valuable insights into the mechanism of pericarp dehiscence and anthocyanin biosynthesis in banana, which will significantly contribute to future genetic and molecular breeding efforts.

Genome assembly of Ottelia alismoides, a multiple-carbon utilisation aquatic plant.

OBJECTIVES: Ottelia Pers. is in the Hydrocharitaceae family. Species in the genus are aquatic, and China is their centre of origin in Asia. Ottelia alismoides (L.) Pers., which is distributed worldwide, is a distinguishing element in China, while other species of this genus are endemic to China. However, O. alismoides is also considered endangered due to habitat loss and pollution in some Asian countries. Ottelia alismoides is the only submerged macrophyte that contains three carbon dioxide-concentrating mechanisms, i.e. bicarbonate (HCO3-) use, crassulacean acid metabolism and the C4 pathway. In this study, we present its first genome assembly to help illustrate the various carbon metabolism mechanisms and to enable genetic conservation in the future. DATA DESCRIPTION: Using DNA and RNA extracted from one O. alismoides leaf, this work produced ∼ 73.4 Gb HiFi reads, ∼ 126.4 Gb whole genome sequencing short reads and ∼ 21.9 Gb RNA-seq reads. The de novo genome assembly was 6,455,939,835 bp in length, with 11,923 scaffolds/contigs and an N50 of 790,733 bp. Genome assembly completeness assessment with Benchmarking Universal Single-Copy Orthologs revealed a score of 94.4%. The repetitive sequence in the assembly was 4,875,817,144 bp (75.5%). A total of 116,176 genes were predicted. The protein sequences were functionally annotated against multiple databases, facilitating comparative genomic analysis.

Draft genome of Brasenia schreberi, a worldwide distributed and endangered aquatic plant.

OBJECTIVES: Brasenia is a monotypic genus in the family of Cabombaceae. The only species, B. schreberi, is a macrophyte distributed worldwide. Because it requires good water quality, it is endangered in China and other countries due to the deterioration of aquatic habitats. The young leaves and stems of B. schreberi are covered by thick mucilage, which has high medical value. As an allelopathic aquatic plant, it can also be used in the management of aquatic weeds. Here, we present its assembled and annotated genome to help shed light on medial and allelopathic substrates and facilitate their conservation. DATA DESCRIPTION: Genomic DNA and RNA extracted from B. schreberi leaf tissues were used for whole genome and RNA sequencing using a Nanopore and/or MGI sequencer. The assembly was 1,055,148,839 bp in length, with 92 contigs and an N50 of 22,379,495 bp. The repetitive elements in the assembly were 555,442,205 bp. A completeness assessment of the assembly with BUSCO and compleasm indicated 88.4 and 90.9% completeness in the Eudicots database and 95.4 and 96.6% completeness in the Embryphyta database. Gene annotation revealed 67,747 genes that coded for 73,344 proteins.

Characterization of Firmiana danxiaensis plastomes and comparative analysis of Firmiana: insight into its phylogeny and evolution.

BACKGROUND: Firmiana danxiaensis is a critically endangered and ecologically important tree currently only found in four locations in Danxia or Karst habitats in northern Guangdong Province, China. The specialized habitat preference makes it an ideal model species for study of adaptive evolution. Meanwhile, the phylogenetic relationships of F. danxiaensis in four locations under two landforms are unclear. Therefore, we sequenced its complete chloroplast (cp.) genomes and conducted comprehensive interspecific and intrageneric plastome studies. RESULTS: The F. danxiaensis plastomes in four locations showed a typical quadripartite and circular structure that ranged from 160,832 to 161,206 bp in size, with 112 unique genes encoded. Comparative genomics showed that the plastomes of F. danxiaensis were relatively conserved with high similarity of genome organization, gene number, GC content and SSRs. While the genomes revealed higher biased codon preferences in Karst habitat than those in Danxia habitats. Eighteen and 11 divergent hotpots were identified at interspecific and intrageneric levels for species identification and further phylogenetic studies. Seven genes (clpP, accD, ccsA, ndhH, rpl20, rpoC2, and rps4) were under positive selection and may be related to adaptation. Phylogenetic analysis revealed that F. danxiaensis is sister to F. major and F. simplex. However, the interspecific relationships are not consistent with the habitat types. CONCLUSIONS: The characteristics and interspecific relationship of F. danxiaensis plastomes provide new insights into further integration of geographical factors, environmental factors, and genetic variations on the genomic study of F. danxiaensis. Together, our study will contribute to the study of species identification, population genetics, and conservation biology of F. danxiaensis.

Establishment and Characterization of a New Intrahepatic Cholangiocarcinoma Cell Line, ICC-X2.

Background: Intrahepatic cholangiocarcinoma (ICC) is an aggressive malignant tumor of the biliary tract that is prone to recurrence and metastasis and is characterized by poor sensitivity to chemotherapy and overall prognosis. For these reasons, there is an urgent need to understand its pathological mechanisms and develop effective treatments. To address this challenge, the establishment of suitable preclinical models is critical. Methods: Fresh ICC tissue samples were used for primary culture and subculture. The cell line was evaluated by cell proliferation assays, clonal formation assays, karyotype analysis, and short tandem repeat (STR) analysis. Drug resistances against oxaliplatin, paclitaxel, gemcitabine and 5-fluorouracil (5-FU) were evaluated by CCK-8 assay. Subcutaneous injection of 1 × 106 cells to three BALB/c nude mice was conducted for xenograft studies. The hematoxylin and eosin (H&E) staining was used to detect the pathological status of the cell line. The expression of biomarkers CK7, CK19, Ki-67, E-cadherin and vimentin was determined by immunocytochemistry assay. Results: A new ICC cell line named ICC-X2 was successfully established. Like ICC-X3 established using the same patient's metastatic tumor, the cell line has been continuously cultured in vitro for more than a year and has been passaged more than 100 times. ICC-X2 retained the typical biliary epithelial morphology. The population doubling time of ICC-X2 is 48 h. The cells demonstrated an abnormal nearly tetraploid karyotype. The STR analysis confirmed that ICC-X2 was highly consistent with the primary tumor tissue and not cross-contaminated by existing cell lines. ICC-X2 cells positively expressed CK7, CK19, E-cadherin, and vimentin, and the positive expression of Ki-67 in ICC-X2 cells was 40%. The ICC-X2 cells exhibited a strong clonogenic ability. The drug sensitivity test indicated that ICC-X2 was sensitive to oxaliplatin and paclitaxel, but naturally resistant to gemcitabine and 5-FU. ICC-X2 was rapidly able to form transplanted tumors in vivo after subcutaneous inoculation in nude mice. Conclusions: ICC-X2 is an excellent experimental model that can be used for studying the occurrence, development, and metastasis of ICC and investigating the mechanism of tumor drug resistance.

Chromosome-level genome assembly and demographic history of Euryodendron excelsum in monotypic genus endemic to China.

Euryodendron excelsum is in a monotypic genus Euryodendron, endemic to China. It has intermediate morphisms in the Pentaphylacaceae or Theaceae families, which make it distinct. Due to anthropogenic disturbance, E. excelsum is currently found in very restricted and fragmented areas with extremely small populations. Although much research and effort has been applied towards its conservation, its long-term survival mechanisms and evolutionary history remain elusive, especially from a genomic aspect. Therefore, using a combination of long/short whole genome sequencing, RNA sequencing reads, and Hi-C data, we assembled and annotated a high-quality genome for E. excelsum. The genome assembly of E. excelsum comprised 1,059,895,887 bp with 99.66% anchored into 23 pseudo-chromosomes and a 99.0% BUSCO completeness. Comparative genomic analysis revealed the expansion of terpenoid and flavonoid secondary metabolite genes, and displayed a tandem and/or proximal duplication framework of these genes. E. excelsum also displayed genes associated with growth, development, and defence adaptation from whole genome duplication. Demographic analysis indicated that its fluctuations in population size and its recent population decline were related to cold climate changes. The E. excelsum genome assembly provides a highly valuable resource for evolutionary and ecological research in the future, aiding its conservation, management, and restoration.

Draft genome of Castanopsis chinensis, a dominant species safeguarding biodiversity in subtropical broadleaved evergreen forests.

OBJECTIVES: Castanopsis is the third largest genus in the Fagaceae family and is essentially tropical or subtropical in origin. The species in this genus are mainly canopy-dominant trees, and the key components of evergreen broadleaved forests play a crucial role in the maintenance of local biodiversity. Castanopsis chinensis, distributed from South China to Vietnam, is a representative species. It currently suffers from a high disturbance of human activity and climate change. Here, we present its assembled genome to facilitate its preliminary conservation and breeding on the genome level. DATA DESCRIPTION: The C. chinensis genome was assembled and annotated by Nanopore and MGI whole-genome sequencing and RNA-seq reads using leaf tissues. The assembly was 888,699,661 bp in length, consisting of 133 contigs and a contig N50 of 23,395,510 bp. A completeness assessment of the assembly with Benchmarking Universal Single-Copy Orthologs (BUSCO) indicated a score of 98.3%. Repetitive elements comprised 471,006,885 bp, accounting for 55.9% of the assembled sequences. A total of 51,406 genes that coded for 54,310 proteins were predicted. Multiple databases were used to functionally annotate the protein sequences.

Genome Assembly of Cordia subcordata, a Coastal Protection Species in Tropical Coral Islands.

Cordia subcordata trees or shrubs, belonging to the Boraginaceae family, have strong resistance and have adapted to their habitat on a tropical coral island in China, but the lack of genome information regarding its genetic background is unclear. In this study, the genome was assembled using both short/long whole genome sequencing reads and Hi-C reads. The assembled genome was 475.3 Mb, with 468.7 Mb (99.22%) of the sequences assembled into 16 chromosomes. Repeat sequences accounted for 54.41% of the assembled genome. A total of 26,615 genes were predicted, and 25,730 genes were functionally annotated using different annotation databases. Based on its genome and the other 17 species, phylogenetic analysis using 336 single-copy genes obtained from ortholog analysis showed that C. subcordata was a sister to Coffea eugenioides, and the divergence time was estimated to be 77 MYA between the two species. Gene family evolution analysis indicated that the significantly expanded gene families were functionally related to chemical defenses against diseases. These results can provide a reference to a deeper understanding of the genetic background of C. subcordata and can be helpful in exploring its adaptation mechanism on tropical coral islands in the future.

Genome assembly of Erythrophleum Fordii, a special "ironwood" tree in China.

OBJECTIVES: Erythrophleum is a genus in the Fabaceae family. The genus contains only about 10 species, and it is best known for its hardwood and medical properties worldwide. Erythrophleum fordii Oliv. is the only species of this genus distributed in China. It has superior wood and can be used in folk medicine, which leads to its overexploitation in the wild. For its effective conservation and elucidation of the distinctive genetic traits of wood formation and medical components, we present its first genome assembly. DATA DESCRIPTION: This work generated ~ 160.8 Gb raw Nanopore whole genome sequencing (WGS) long reads, ~ 126.0 Gb raw MGI WGS short reads and ~ 29.0 Gb raw RNA-seq reads using E. fordii leaf tissues. The de novo assembly contained 864,825,911 bp in the E. fordii genome, with 59 contigs and a contig N50 of 30,830,834 bp. Benchmarking Universal Single-Copy Orthologs (BUSCO) revealed 98.7% completeness of the assembly. The assembly contained 471,006,885 bp (54.4%) repetitive sequences and 28,761 genes that coded for 33,803 proteins. The protein sequences were functionally annotated against multiple databases, facilitating comparative genomic analysis.

Draft genome and transcriptome of Nepenthes mirabilis, a carnivorous plant in China.

OBJECTIVES: Nepenthes belongs to the monotypic family Nepenthaceae, one of the largest carnivorous plant families. Nepenthes species show impressive adaptive radiation and suffer from being overexploited in nature. Nepenthes mirabilis is the most widely distributed species and the only Nepenthes species that is naturally distributed within China. Herein, we reported the genome and transcriptome assemblies of N. mirabilis. The assemblies will be useful resources for comparative genomics, to understand the adaptation and conservation of carnivorous species. DATA DESCRIPTION: This work produced ~ 139.5 Gb N. mirabilis whole genome sequencing reads using leaf tissues, and ~ 21.7 Gb and ~ 27.9 Gb of raw RNA-seq reads for its leaves and flowers, respectively. Transcriptome assembly obtained 339,802 transcripts, in which 79,758 open reading frames (ORFs) were identified. Function analysis indicated that these ORFs were mainly associated with proteolysis and DNA integration. The assembled genome was 691,409,685 bp with 159,555 contigs/scaffolds and an N50 of 10,307 bp. The BUSCO assessment of the assembled genome and transcriptome indicated 91.1% and 93.7% completeness, respectively. A total of 42,961 genes were predicted in the genome identified, coding for 45,461 proteins. The predicted genes were annotated using multiple databases, facilitating future functional analyses of them. This is the first genome report on the Nepenthaceae family.

The complete chloroplast genome sequence of Durio oxleyanus (Malvaceae) and its phylogenetic position.

Durio oxleyanus (Griff) of Malvaceae is considered a natural heritage by the countries that produce it, including Peninsular Malaysia, Sumatra, and Borneo. Even though the species is regarded as a commercially valuable fruit, cultivation of this species is uncommon. The dwindling population of this species in the wild has put its survival in jeopardy. Conservation efforts are required for this species, which are limited. In this study, the complete chloroplast (cp) genome of D. oxleyanus was assembled and characterized as a genomic resource for conservation programs. The complete cp genome size was 164,831 bp in length, with a pair of inverted repeats of 23,782 bp each, separating the 96,446-bp large and the 20,823-bp small single copies. A total of 135 genes were predicted, which consisted of 90 protein-coding, 37 tRNA, and eight rRNA genes. The overall GC content was 35.8%. The phylogenetic analysis based on the maximum-likelihood and Bayesian inference methods revealed that D. oxleyanus is closely related to D. zibethinus. The genomic data obtained will be useful for future studies of Malvaceae's phylogenetics and evolution.

The complete chloroplast genome of Prunus campanulata 'Fugui' (Rosaceae).

Prunus campanulata 'Fugui' is newly bred cultivar. Here, we report its complete chloroplast genome. The length of the P. campanulata 'Fugui' chloroplast genome is 157,948 bp, with a large single-copy region of 85,948 bp, a small single-copy region of 19,128 bp and a pair of inverted repeat regions of 26,436 bp each. The genome contains 90 protein-coding genes, 65 transfer RNA genes and 9 ribosomal RNA genes. In addition, the genome contains 67 simple sequence repeats. Phylogenetic analysis revealed that P. campanulata 'Fugui' is genetically related to previously reported P. campanulata.

Choledocholithiasis characteristics with periampullary diverticulum and endoscopic retrograde cholangiopancreatography procedures: Comparison between two centers from Lanzhou and Kyoto.

BACKGROUND: Most of study regarding periampullary diverticulum (PAD) impact on endoscopic retrograde cholangiopancreatography (ERCP) therapy for choledocholithiasis based on data from one endoscopy center and lacked to compare the clinical characteristic of choledocholithiasis with PAD from different geographical patients. AIM: To compare the choledocholithiasis clinical characteristics between two regional endoscopy centers and analyze impacts of clinical characteristics on ERCP methods for choledocholithiasis patients with PAD. METHODS: Patients seen in two endoscopy centers (The First Hospital of Lanzhou University, Lanzhou, Gansu Province, China, and Kyoto Second Red Cross Hospital, Kyoto, Japan) underwent ERCP treatment for the first time between January 2012 and December 2017. The characteristics of choledocholithiasis with PAD were compared between the two centers, and their ERCP procedures and therapeutic outcomes were analyzed. RESULTS: A total of 829 out of 3608 patients in the Lanzhou center and 241 out of 1198 in the Kyoto center had choledocholithiasis with PAD. Lots of clinical characteristics were significantly different between the two centers. The common bile duct (CBD) diameter was wider, choledocholithiasis size was lager and multiple CBD stones were more in the Lanzhou center patients than those in the Kyoto center patients (14.8 ± 5.2 mm vs 11.6 ± 4.2 mm, 12.2 ± 6.5 mm vs 8.2 ± 5.3 mm, 45.3% vs 20.3%, P < 0.001 for all). In addition, concomitant diseases, such as acute cholangitis, gallbladder stones, obstructive jaundice, cholecystectomy, and acute pancreatitis, were significantly different between the two centers (P = 0.03 to < 0.001). In the Lanzhou center, CBD diameter and choledocholithiasis size were lower, and multiple CBD stones and acute cholangitis were less in non-PAD patients than those in PAD patients (13.4 ± 5.1 mm vs 14.8 ± 5.2 mm, 10.3 ± 5.4 mm vs 12.2 ± 6.5, 39% vs 45.3%, 13.9% vs 18.5%, P = 0.002 to < 0.001). But all these characteristics were not significantly different in the Kyoto center. The proportions of endoscopic sphincterotomy (EST), endoscopic balloon dilatation (EPBD), and EST+EPBD were 50.5%, 1.7%, and 42.5% in the Lanzhou center and 90.0%, 0.0%, and 0.4% in the Kyoto center, respectively. However, the overall post-ERCP complication rate was not significantly different between the two centers (8.9% in the Lanzhou and 5.8% in the Kyoto. P = 0.12). In the Lanzhou center, the difficulty rate in removing CBD stones in PAD was higher than in non-PAD group (35.3% vs 26.0%, P < 0.001). But the rate was no significant difference between the two groups in Kyoto center. The residual rates of choledocholithiasis were not significantly different between the two groups in both centers. Post-ERCP complications occurred in 8.9% of the PAD patients and 8.1% of the non-PAD patients in the Lanzhou Center, and it occurred in 5.8% in PAD patients and 10.0% in non-PAD patients in the Kyoto center, all P > 0.05. CONCLUSION: Many clinical characteristics of choledocholithiasis patients with PAD were significantly different between the Lanzhou and Kyoto centers. The patients had larger and multiple stones, wider CBD diameter, and more possibility of acute cholangitis and obstructive jaundice in the Lanzhou center than those in the Kyoto center. The ERCP procedures to manage native duodenal papilla were different depending on the different clinical characteristics while the overall post-ERCP complications were not significantly different between the two centers. The stone residual rate and post-ERCP complications were not significantly different between choledocholithiasis patients with PAD and without PAD in each center.

The genome of the Paleogene relic tree Bretschneidera sinensis: insights into trade-offs in gene family evolution, demographic history, and adaptive SNPs.

Among relic species, genomic information may provide the key to inferring their long-term survival. Therefore, in this study, we investigated the genome of the Paleogene relic tree species, Bretschneidera sinensis, which is a rare endemic species within southeastern Asia. Specifically, we assembled a high-quality genome for B. sinensis using PacBio high-fidelity and high-throughput chromosome conformation capture reads and annotated it with long and short RNA sequencing reads. Using the genome, we then detected a trade-off between active and passive disease defences among the gene families. Gene families involved in salicylic acid and MAPK signalling pathways expanded as active defence mechanisms against disease, but families involved in terpene synthase activity as passive defences contracted. When inferring the long evolutionary history of B. sinensis, we detected population declines corresponding to historical climate change around the Eocene-Oligocene transition and to climatic fluctuations in the Quaternary. Additionally, based on this genome, we identified 388 single nucleotide polymorphisms (SNPs) that were likely under selection, and showed diverse functions in growth and stress responses. Among them, we further found 41 climate-associated SNPs. The genome of B. sinensis and the SNP dataset will be important resources for understanding extinction/diversification processes using comparative genomics in different lineages.

Genome assembly of Musa beccarii shows extensive chromosomal rearrangements and genome expansion during evolution of Musaceae genomes.

BACKGROUND: Musa beccarii (Musaceae) is a banana species native to Borneo, sometimes grown as an ornamental plant. The basic chromosome number of Musa species is x = 7, 10, or 11; however, M. beccarii has a basic chromosome number of x = 9 (2n = 2x = 18), which is the same basic chromosome number of species in the sister genera Ensete and Musella. Musa beccarii is in the section Callimusa, which is sister to the section Musa. We generated a high-quality chromosome-scale genome assembly of M. beccarii to better understand the evolution and diversity of genomes within the family Musaceae. FINDINGS: The M. beccarii genome was assembled by long-read and Hi-C sequencing, and genes were annotated using both long Iso-seq and short RNA-seq reads. The size of M. beccarii was the largest among all known Musaceae assemblies (∼570 Mbp) due to the expansion of transposable elements and increased 45S ribosomal DNA sites. By synteny analysis, we detected extensive genome-wide chromosome fusions and fissions between M. beccarii and the other Musa and Ensete species, far beyond those expected from differences in chromosome number. Within Musaceae, M. beccarii showed a reduced number of terpenoid synthase genes, which are related to chemical defense, and enrichment in lipid metabolism genes linked to the physical defense of the cell wall. Furthermore, type III polyketide synthase was the most abundant biosynthetic gene cluster (BGC) in M. beccarii. BGCs were not conserved in Musaceae genomes. CONCLUSIONS: The genome assembly of M. beccarii is the first chromosome-scale genome assembly in the Callimusa section in Musa, which provides an important genetic resource that aids our understanding of the evolution of Musaceae genomes and enhances our knowledge of the pangenome.

The complete chloroplast genome of Ormosia purpureiflora (Fabaceae).

Ormosia purpureiflora is endemic to China. It is named after its purple flowers. It is a small tree only up to 3 m. It has leathery leaves, racemose inflorescences. The seeds are elliptic and red in coat. It is only confined to Luofushan Provincial Nature Reserve in Huizhou of Guangdong Province. Herein, we first reported on its complete chloroplast genome sequence as genomic resource for conservation purposes. The chloroplast genome of O. purpureiflora was 173,364 bp in length, with a large single-copy region of 73,465 bp, a small single-copy region of 18,751 bp, and a pair of inverted repeat regions that were 40,574 bp each. A total of 90 protein-coding genes, 38 transfer RNA genes, and eight ribosomal RNA genes were predicted, while 106 simple sequence repeats were recorded throughout the genome. Phylogenetic analysis revealed that O. purpureiflora was sister to O. emarginata.

The complete chloroplast genome of Rhododendron kawakamii (Ericaceae).

Rhododendron kawakamii is endemic in Taiwan island and is a unique and epiphytic species. Here, we report its complete chloroplast genome. The length of the R. kawakamii chloroplast genome is 230,777 bp, with a large single-copy region of 146,155 bp, a small single-copy region of 72,082 bp, and a pair of inverted repeat regions (IRA) of 6,270 bp each. The genome contains 77 protein-coding genes, 29 transfer RNA genes, and four ribosomal RNA genes. In addition, the genome contains 81 simple sequence repeats. Phylogenetic analysis revealed that R. kawakamii is genetically related to R. datiandingense.

The complete mitochondrial genome of Ormosia boluoensis.

Ormosia is a particular genus in the Fabaceae family with its striking seeds. The genus Ormosia boluoensis is a newly reported and critically endangered species, and field investigations have indicated that there are only hundreds of it. For the effective conservation, we report its complete mitochondrial genome. The length of the O. boluoensis mitochondrial genome is 248,619 bp, including 28 protein-coding genes, 14 transfer RNA genes, 3 ribosomal RNA genes, and 45 simple sequence repeats. Phylogenetic analysis revealed that O. boluoensis was a sister to the clade including Sophora flavescens, Ammopiptanthus nanus, and Ammopiptanthus mongolicus.