The chromosome-level genomes of the herbal magnoliids Warburgia ugandensis and Saururus chinensis.

Warburgia ugandensis and Saururus chinensis are two of the most important medicinal plants in magnoliids and are widely utilized in traditional Kenya and Chinese medicine, respectively. The absence of higher-quality reference genomes has hindered research on the medicinal compound biosynthesis mechanisms of these plants. We report the chromosome-level genome assemblies of W. ugandensis and S. chinensis, and generated 1.13 Gb and 0.53 Gb genomes from 74 and 27 scaffolds, respectively, using BGI-DIPSEQ, Nanopore, and Hi-C sequencing. The scaffold N50 lengths were 82.97 Mb and 48.53 Mb, and the assemblies were anchored to 14 and 11 chromosomes of W. ugandensis and S. chinensis, respectively. In total, 24,739 and 20,561 genes were annotated, and 98.5% and 98% of the BUSCO genes were fully represented, respectively. The chromosome-level genomes of W. ugandensis and S. chinensis will be valuable resources for understanding the genetics of these medicinal plants, studying the evolution of magnoliids and angiosperms and conserving plant genetic resources.

Development of the petaloid bracts of a paleoherb species, Saururus chinensis.

Saururus chinensis is a core member of Saururaceae, an ancient, perianthless (lacking petals or sepals) family of the magnoliids in the Mesangiospermae, which is important for understanding the origin and evolution of early flowers due to its unusual floral composition and petaloid bracts. To compare their transcriptomes, RNA-seq abundance analysis identified 43,463 genes that were found to be differentially expressed in S. chinensis bracts. Of these, 5,797 showed significant differential expression, of which 1,770 were up-regulated and 4,027 down-regulated in green compared to white bracts. The expression profiles were also compared using cDNA microarrays, which identified 166 additional differentially expressed genes. Subsequently, qRT-PCR was used to verify and extend the cDNA microarray results, showing that the A and B class MADS-box genes were up-regulated in the white bracts. Phylogenetic analysis was performed on putative S. chinensis A and B-class of MADS-box genes to infer evolutionary relationships within the A and B-class of MADS-box gene family. In addition, nature selection and protein interactions of B class MADS-box proteins were inferred that B-class genes free from evolutionary pressures. The results indicate that petaloid bracts display anatomical and gene expression features normally associated with petals, as found in petaloid bracts of other species, and support an evolutionarily conserved developmental program for petaloid bracts.

Optimization of DNA isolation and PCR protocol for analysis and evaluation of genetic diversity of the medicinal plant, Anemopsis californica using RAPD.

Anemopsis californica is a perennial herbaceous plant that has been utilized as a medicinal plant for the treatment of various diseases. The present work was carried out with the objective of optimizing a method of extraction of the genomic DNA of A. californica and a PCR protocol and later to evaluate the existing genetic diversity among the genotypes deriving from different origins. For DNA extraction, we tested four procedures: with the CTA B-2 protocol, we obtained the highest yield (61.5±2.2 µg DNA/g of leaf tissues) and the best quality (A260/280 1.83±0.022). To estimate genetic variability, we utilized the randomly amplified polymorphism DNA (RAPD) technique, employing 20 oligonucleotides, of which only 18 generated reproducible banding patterns, producing 123 polymorphic bands generated, thus obtaining a polymorphism rate of 93.93% among the genotypes analyzed. The Jaccard similarity coefficient generated a variation ranging from 0.325-0.921, indicating a high level of genetic variation among the studied genotypes. An Unweighted pair-group method with arithmetic mean (UPGMA) group analysis indicated six distinct groups. The present optimized method for DNA isolation and RAPD protocol may serve as an efficient tool for further molecular studies.

Developmental genetics of the perianthless flowers and bracts of a paleoherb species, Saururus chinensis.

Saururus chinensis is a core member of Saururaceae, a perianthless (lacking petals or sepals) family. Due to its basal phylogenetic position and unusual floral composition, study of this plant family is important for understanding the origin and evolution of perianthless flowers and petaloid bracts among angiosperm species. To isolate genes involved in S. chinensis flower development, subtracted floral cDNA libraries were constructed by using suppression subtractive hybridization (SSH) on transcripts isolated from developing inflorescences and seedling leaves. The subtracted cDNA libraries contained a total of 1,141 ESTs and were used to create cDNA microarrays to analyze transcript profiles of developing inflorescence tissues. Subsequently, qRT-PCR analyses of eight MADS-box transcription factors and in situ hybridizations of two B-class MADS-box transcription factors were performed to verify and extend the cDNA microarray results. Finally, putative phylogenetic relationships within the B-class MADS-box gene family were determined using the discovered S. chinensis B-class genes to compare K-domain sequences with B genes from other basal angiosperms. Two hundred seventy-seven of the 1,141 genes were found to be expressed differentially between S. chinensis inflorescence tissues and seedling leaves, 176 of which were grouped into at least one functional category, including transcription (14.75%), energy (12.59%), metabolism (9.12%), protein-related function (8.99%), and cellular transport (5.76%). qRT-PCR and in situ hybridization of selected MADS-box genes supported our microarray data. Phylogenetic analysis indicated that a total of six B-class MADS-box genes were isolated from S. chinensis. The differential regulation of S. chinensis B-class MADS-box transcription factors likely plays a role during the development of subtending bracts and perianthless flowers. This study contributes to our understanding of inflorescence development in Saururus, and represents an initial step toward understanding the formation of petaloid bracts in this species.

Inhibition of NF-IL6 activity by manassantin B, a dilignan isolated from Saururus chinensis, in phorbol myristate acetate-stimulated U937 promonocytic cells.

Mannasantin B, a dilignan structurally related to manssantin A, is an inhibitor of NF-kappaB transactivation. In the present study, we found that it inhibited PMA-induced expression of IL-1beta, IL-1beta mRNA, and IL-1beta promoter activity in U937 cells with IC50 values of about 50 nM. It also inhibited NF-IL6- and NF-kappaB-induced activation of IL-1beta, with IC50 values of 78 nM and 1.6 microM, respectively, revealing a potent inhibitory effect on NF-IL6. Electrophoretic mobility shift assays showed that manassantin B had an inhibitory effect on DNA binding by NF-IL6, but not by NF-kappaB. Further analysis revealed that transactivation by NF-IL6 was also inhibited. Our results indicate that manassantin B suppresses expression of IL-1beta in promonocytic cells by inhibiting not only NF-kappaB but also NF-IL6 activity. Furthermore, our observations suggest that manassantin B may be clinically useful as a potent inhibitor of NF-IL6 activity.

PCR-RFLP analysis of cpDNA and mtDNA in the genus Houttuynia in some areas of China.

Plasmon diversity of 70 Houttuynia Thunb. accessions were investigated by using PCR-RFLP technology. The results not only revealed the interspecific, but also intraspecific plasmon variations within the genus Houttuynia. In total, 59 distinct organelle haplotypes were identified among 70 accessions, two in H. emeiensis and 57 in H. cordata. The average genetic similarities (GSs) values within H. emeiensis and H. cordata accessions were 0.986 and 0.950, respectively. The intraspecific GS value between H. emeiensis and H. cordata was 0.951. Two accessions of the new species H. emeiensis, W01-1 and W01-86, were very closely clustered together, but they could not be completely separated from H. cordata according to the cluster analysis. The results suggest that the classification of new species could be reconsidered. The level of genetic diversity between cultivated and wild groups in H. cordata was very low. The groups based on plasmon PCR-RFLP GS were little related with geographic distribution and chromosome number. We also discuss the phylogenetic relationship and phylogeographic information of the genus Houttuynia.