The chemical constituents from twigs of Hamamelis japonica and their antiviral activities

Three new monoterpenoid glycosides (1-3) and one new flavanol (4) along with 15 known compounds were isolated from the twig of Hamamelis japonica Sieb. et Zucc. The chemical constituent study of the twig of H. japonica has performed for the first time in the present investigation. Their structures were determined based on extensive spectroscopic methods including 1 D and 2 D NMR and CD spectra data. All isolated compounds were tested for their antiviral activities against HRV1B-, EV71-, PR8- and CVB3-infected Vero cells. Among the tested compounds, (-)-epigallocatechin 3-O-gallate exhibited the most consistent and effective antiviral activities against EV71 and PR8 infections.

Chloroplast phylogenomic insights into the evolution of Distylium (Hamamelidaceae)

BACKGROUND

Most Distylium species are endangered. Distylium species mostly display homoplasy in their flowers and fruits, and are classified primarily based on leaf morphology. However, leaf size, shape, and serration vary tremendously making it difficult to use those characters to identify most species and a significant challenge to address the taxonomy of Distylium. To infer robust relationships and develop variable markers to identify Distylium species, we sequenced most of the Distylium species chloroplast genomes.

RESULTS

The Distylium chloroplast genome size was 159,041-159,127 bp and encoded 80 protein-coding, 30 transfer RNAs, and 4 ribosomal RNA genes. There was a conserved gene order and a typical quadripartite structure. Phylogenomic analysis based on whole chloroplast genome sequences yielded a highly resolved phylogenetic tree and formed a monophyletic group containing four Distylium clades. A dating analysis suggested that Distylium originated in the Oligocene (34.39 Ma) and diversified within approximately 1 Ma. The evidence shows that Distylium is a rapidly radiating group. Four highly variable markers, matK-trnK, ndhC-trnV, ycf1, and trnT-trnL, and 74 polymorphic simple sequence repeats were discovered in the Distylium plastomes.

CONCLUSIONS

The plastome sequences had sufficient polymorphic information to resolve phylogenetic relationships and identify Distylium species accurately.

The complete chloroplast genome sequence of Corylopsis multiflora Hance var. nivea Chang

Corylopsis multiflora Hance var. nivea Chang is a variety of the species C. multiflora in the family Hamamelidaceae and is classed as critically endangered (CR) in the Red List of China Higher Plants. The complete chloroplast genome sequence of this taxon (as C. multiflora var. nivea in GeneBank, accession number: MW043717) was reported in this study. The genome size is 158,993 bp in length, consisting of a pair of inverted repeat regions (IR, 26,213bp), large single copy (LSC, 87,895bp) and small single copy (SSC, 18,672bp). A total of 133 genes were annotated that included 87 protein coding genes (PCGs), 37 transfer RNA (tRNAs), and 8 ribosome RNA (rRNAs) and 1 pseudo gene. GC content were 38.01%. The Bayesian phylogeny tree showed that C. multiflora var. nivea formed a monophyletic branch with Corylopis coreana and Corylopsis spicata.

Triterpenoids from Liquidambar Fructus induced cell apoptosis via a PI3K-AKT related signal pathway in SMMC7721 cancer cells

A previously undescribed taraxerene-type triterpenoid possessing a class of rare natural taraxerene triterpenoid possessing skeleton with 14, 28-lactone, two undescribed oleane-type triterpenoids, and twenty-five known triterpenoids were isolated from Liquidambar formosana (Hamamelidaceae). The structures of undescribed compounds were determined on the basis of 1D and 2D NMR spectroscopic, HR-ESI-MS, and X-ray crystallographic data analysis. Among the isolates, ursolic acid, 3,6-dion-20(29)-lupen-28-oic acid, and 3-oxo-12α-hydroxyoleanan-28,13β-olide induced a significant apoptosis in SMMC7721 cells in the flow cytometer experiment with apoptosis rates of 94.5%, 57.3% and 89.9% at 8.0 μM, respectively, exhibiting near equivalent apoptosis-inducing abilities to that positive drug taxol (apoptotic rate of 71.2% at 1.4 μM). Mechanism studies suggested that these three compounds could regulate the mitochondrial pathway by up-regulating the expressions of pro-apoptotic factors (Bad and Bax) and activating caspase-3 and caspase-9 to induce apoptosis. Further studies indicated that the pro-apoptotic effects of these three compounds were associated with PI3K-AKT pathway inhibition. Taken together, these studies provide evidence that triterpenoids from L. Fructus are promising candidates for the hepatocellular carcinoma therapy.

The complete chloroplast genome of Distylium tsiangii Chun ex Walker, a rare and endangered plant

Distylium tsiangii Chun ex Walker is an evergreen tree species endemic to China. It has been classified as critically endangered in the Red List of China Higher Plants. Here, we sequenced, assembled, and analyzed the complete chloroplast (cp) genome of D. tsiangii. The plastome is 159,125 bp in length, with a typical quadripartite structure and consisting of a pair of inverted repeat (IR) regions (26,220 bp) separated by a large single copy (LSC) region (87,897 bp) and a small single copy (SSC) region (18,788 bp). The overall GC content was 38.00%. A total of 131 genes were annotated, including 37 tRNA genes, 86 protein-coding genes, and eight rRNA genes. Phylogenetic analysis showed that D. tsiangii was more closely related to Parrotia subaequalis.

Complete plastome sequence of Rhodoleia championii Hook. f. (Hamamelidaceae)

The complete chloroplast genome of Rhodoleia championii (Hamamelidaceae) was firstly reported in this study. The complete chloroplast genome of R. championii is 159,115 bp in length with a typical quadripartite structure, consisting of a large single-copy region (LSC, 88,123 bp), a single-copy region (SSC, 18,131 bp) and a pair of inverted repeats (IRs, 26,420 bp). There are 114 genes annotated, including 80 unique protein-coding genes, 4 unique ribosomal RNA genes, and 30 transfer RNA genes. According to the phylogenetic tree of R. championii and the other 9 species, R. championii was closely related to Chunia bucklandioides.

Development and characterization of genomic microsatellite markers in the tree species, Rhodoleia championii, R. parvipetala, and R. forrestii (Hamamelidaceae)

Rhodoleia Champion ex Hooker is one of the most primitive relict genera of Hamamelidaceae, a key family exploited to understand the origin and early evolution of flowering plants. Genomic simple sequence repeats (SSRs) were developed for R. championii to perform genetic diversity, phylogeographical structure or even systematic evolution studies of the genus. Among the 278,743 contigs (105,758,242 bps) de novo assembled from the low-coverage whole genome sequencing of R. championii, a total of 9106 SSRs were detected in 8370 contigs, and SSR primer pairs were successfully designed for 6677 SSRs. Among the 110 selected primer pairs, 41 were amplified successfully in the preliminary test of SSR screening. Further amplification of these 41 primer pairs across the 122 individuals collected from six populations of the three Rhodoleia species showed that 32 and 40 SSR markers can be amplified in Vietnam and Jinping populations of R. parvipetala, 41, 33, and 41 SSR markers in Boluo, Hongkong and Xinyi populations of R. championii, 25 SSR markers in Fugong population of R. forrestii, and 20 SSR markers demonstrated to be polymorphic across the three species. Genetic analysis for these 20 polymorphic SSRs showed that Allele number (A) ranged from four to 13 and polymorphic information content (PIC) ranged from 0.479 to 0.876 across the three species. At the population level, observed heterozygosity (H_O) ranged from 0.000 to 1.000, and expected heterozygosity (H_E) ranged from 0.091 to 0.851. In the present study, we provided the first whole-genome sequencing database for the species R. championii, identified ample SSR loci with designed primers, and revealed that 20 of the 110 selected SSRs were polymorphic across three Rhodoleia species. These provide valuable resources for future studies on genetic study, species delimitation, phylogeography, and conservation of this genus.

Complete chloroplast genome of Corylopsis spicata and phylogenetic analysis

The complete plastid genome of Corylopsis spicata was sequenced and analyzed in this study. It was found to be 159,507 bp and consisted of a large (88,243 bp) and small (18,716 bp) single-copy regions, separated by a pair of identical inverted repeats (26,274 bp). The GC content of the whole genome was 36.9%, and there were 85 unique protein-coding genes, 37 tRNA, and eight rRNA. The gene order and organization were consistent with those of other complete plastid genomes from the Hamamelidaceae. A phylogenetic tree was constructed based on 76 protein-coding genes that demonstrated a sister relationship within the genus Corylopsis.

Identification and development of microsatellite markers in Hamamelis mollis (Hamamelidaceae)

PREMISE OF THE STUDY

Hamamelis mollis (Hamamelidaceae) is a Tertiary relict species endemic to southern China. Polymorphic microsatellite markers were developed to reveal the genetic diversity of this species.

METHODS AND RESULTS

The genome of H. mollis was sequenced and de novo assembled into 642,351 contigs. A total of 72,097 paired primers were successfully designed from 80,282 simple sequence repeat (SSR) markers identified in 63,419 contigs. PCR amplification showed that 96 of the 136 synthesized primers could be successfully amplified, and 22 demonstrated polymorphism. The mean number of alleles, levels of observed heterozygosity, and levels of expected heterozygosity were 4.602 ± 0.140, 0.632 ± 0.020, and 0.696 ± 0.010, respectively. The majority of the 96 primer pairs could be amplified in at least one other Hamamelidaceae species, including Distylium myricoides (60), Loropetalum chinense (39), Exbucklandia populnea (24), and E. tonkinensis (24).

CONCLUSIONS

These microsatellite loci provide abundant genomic SSR markers to evaluate genetic diversity of this woody ornamental plant.

Characterization and development of EST-derived SSR markers in Sinowilsonia henryi (Hamamelidaceae)

PREMISE OF THE STUDY

Polymorphic microsatellite markers were developed to reveal the genetic diversity of extant populations and the mating system of Sinowilsonia henryi (Hamamelidaceae).

METHODS AND RESULTS

In this study, nuclear simple sequence repeat (SSR) markers were developed using the Illumina high-throughput sequencing technique (RNA-Seq). The de novo-assembled transcriptome generated a total of 64,694 unique sequences with an average length of 601 bp. A total of 2941 microsatellite loci were detected. Of the 121 tested loci, 13 loci were polymorphic and eight were monomorphic among 72 individuals representing three natural populations of the species. The number of alleles per locus ranged from one to four, and the observed and expected heterozygosity at population level were 0.00-1.00 and 0.10-0.66, respectively.

CONCLUSIONS

The developed expressed sequence tag (EST)-SSRs will be useful for studying genetic diversity of S. henryi as well as assessing the mating system among Sinowilsonia species.

Isolation and identification of EST-SSR markers in Chunia bucklandioides (Hamamelidaceae)

PREMISE OF THE STUDY

Chunia bucklandioides (Hamamelidaceae), endemic to Hainan, China, is listed as threatened in the IUCN Red List and is now only found on Mt. Diaoluo and Mt. Jianfeng. Thus, microsatellite markers were developed for future conservation genetic studies of this species.

METHODS AND RESULTS

A total of 115 primers were designed on the basis of the transcriptome data of C. bucklandioides. Of them, 59 successfully amplified in C. bucklandioides and polymorphisms were detected in 11; the number of alleles per locus varied from two to five, the observed heterozygosity ranged from 0.000 to 0.941, and the expected heterozygosity ranged from 0.000 to 0.699. A total of 13 primers amplified in Mytilaria laosensis, and five primers amplified in Exbucklandia tonkinensis and E. populnea.

CONCLUSIONS

The markers screened here provide a basis to assess genetic structure and further establish conservation strategies for C. bucklandioides.

Development of microsatellites from Fothergilla ×intermedia (Hamamelidaceae) and cross transfer to four other genera within Hamamelidaceae

PREMISE OF THE STUDY

We developed microsatellites from Fothergilla ×intermedia to establish loci capable of distinguishing species and cultivars, and to assess genetic diversity for use by ornamental breeders and to transfer within Hamamelidaceae.

METHODS AND RESULTS

We sequenced a small insert genomic library enriched for microsatellites to develop 12 polymorphic microsatellite loci. The number of alleles detected ranged from four to 15 across five genera within Hamamelidaceae. Shannon's information index ranged from 0.07 to 0.14.

CONCLUSIONS

These microsatellite loci provide a set of markers to evaluate genetic diversity of natural and cultivated collections and assist ornamental plant breeders for genetic studies of five popular genera of woody ornamental plants.