Background: Species in genus Amomum always have important medicinal and economic values. Classification of Amomum using morphological characters has long been a challenge because they exhibit high similarity. The main goals of this study were to mine genetic markers from cp genomes for Amomum species identification and discover their evolutionary history through comparative analysis. Results: Three species Amomum villosum, Amomum maximum and Amomum longipetiolatum were sequenced and annotated for the complete chloroplast (cp) genomes, and the cp genomes of A. longipetiolatum and A. maximum were the first reported. Three cp genomes exhibited typical quadripartite structures with 163,269-163,591 bp in length. Each genome encodes 130 functional genes including 79 protein-coding, 26 tRNAs and 3 rRNAs genes. 113-152 SSRs and 99 long repeats were identified in the three cp genomes. By designing specific primers, we amplified the highly variable loci and the mined genetic marker ccsA exhibited a relatively high species identification resolution in Amomum. The nonsynonymous and synonymous substitution ratios (Ka/Ks) in Amomum and Alpinia showed that most genes were subjected to a purifying selection. Phylogenetic analysis revealed the evolutionary relationships of Amomum and Alpinia species and proved that Amomum is paraphyletic. In addition, the sequenced sample of A. villosum was found to be a hybrid, becoming the first report of natural hybridization of this genus. Meanwhile, the high-throughput sequencing-based ITS2 analysis was proved to be an efficient tool for interspecific hybrid identification and with the help of the chloroplast genome, the hybrid parents can be also be determined. Conclusion: The comparative analysis and mined genetic markers of cp genomes were conducive to species identification and evolutionary relationships of Amomum.

Background: Amomum villosum Lour. is the plant that produces the famous traditional Chinese medicine Amomi Fructus. Frequent habitat destruction seriously threatens A. villosum germplasm resources. Genetic diversity is very important to the optimization of germplasm resources and population protection, but the range of inherited traits within A. villosum is unclear. In this study, we analyzed the genetic diversity and genetic structures of A. villosum populations in Guangdong and constructed a local reference DNA barcode library as a resource for conservation efforts. Methods: DNA barcoding and Inter-Simple Sequence Repeat (ISSR) markers were used to investigate the population genetics of A. villosum. Five universal DNA barcodes were amplified and used in the construction of a DNA barcode reference library. Parameters including percentage of polymorphic sites (PPB), number of alleles (Na), effective number of alleles (Ne), Nei’s gene diversity index (H), and Shannon’s polymorphism information index (I) were calculated for the assessment of genetic diversity. Genetic structure was revealed by measuring Nei’s gene differentiation coefficient (Gst), total population genetic diversity (Ht), intra-group genetic diversity (Hs), and gene flow (Nm). Analysis of molecular variance (AMOVA), Mantel tests, unweighted pair-group method with arithmetic mean (UPGMA) dendrogram, and principal co-ordinates (PCoA) analysis were used to elucidate the genetic differentiation and relationship among populations. Results: A total of 531 sequences were obtained from the five DNA barcodes with no variable sites from any of the barcode sequences. A total of 66 ISSR bands were generated from A. villosum populations using the selected six ISSR primers; 56 bands, 84.85% for all the seven A. villosum populations were polymorphic. The A. villosum populations showed high genetic diversity (H = 0.3281, I = 0.4895), whereas the gene flow was weak (Nm = 0.6143). Gst (0.4487) and AMOVA analysis indicated that there is obvious genetic differentiation amongA. villosum populations and more genetic variations existed within each population. The genetic relationship of each population was relatively close as the genetic distances were between 0.0844 and 0.3347.

Background: It is generally accepted that nuclear genes in eukaryotes are located independently on chromosomes and expressed in a monocistronic manner. However, accumulating evidence suggests a more complex landscape of gene structure and transcription. Ganoderma lingzhi, a model medicinal fungus, currently lacks high-quality genome annotation, hindering genetic studies. Results: Here, we reported a golden annotation of G. lingzhi, featuring 14,147 high-confidence genes derived from extensive manual corrections. Novel characteristics of gene structure and transcription were identified accordingly. Notably, non-canonical splicing sites accounted for 1.99% of the whole genome, with the predominant types being GC-AG (1.85%), GT-AC (0.05%), and GT-GG (0.04%). 1165 pairs of genes were found to have overlapped transcribed regions, and 92.19% of which showed opposite directions of gene transcription. A total of 5,412,158 genetic variations were identified among 13 G. lingzhi strains, and the manually corrected gene sets resulted in enhanced functional annotation of these variations. More than 60% of G. lingzhi genes were alternatively spliced. In addition, we found that two or more protein-coding genes (PCGs) can be transcribed into a single RNA molecule, referred to as polycistronic genes. In total, 1272 polycistronic genes associated with 2815 PCGs were identified. Conclusions: The widespread presence of polycistronic genes in G. lingzhi strongly complements the theory that polycistron is also present in eukaryotic genomes. The extraordinary gene structure and transcriptional activity uncovered through this golden annotation provide implications for the study of genes, genomes, and related studies in G. lingzhi and other eukaryotes.

Heat stress is one of the most frequently encountered environmental stresses for most mushroom-forming fungi. Currently available fungal genomes are mostly haploid because high heterozygosity hinders diploid genome assembly.

Introduction: The root of Reynoutria multiflora (Thunb.) Moldenke (RM) has been used widely in formulations of herbal medicines in China for centuries. Raw R. multiflora (RRM) should be processed before use to reduce toxicity and increase efficacy. However, detailed regulation of the processing endpoint is lacking, and the duration of processing can vary considerably. We conducted in-depth research on stilbene glycosides in RM at different processing times. Previously, we discovered that 219 stilbene glycosides changed markedly in quantity and content. Therefore, we proposed that processing causes changes in various chemical groups.Methods: To better explain the mechanism of RM processing for toxicity reduction and efficacy enhancement, we used a method of tandem mass spectrometry described previously to research gallic acid based and catechin based metabolites.Results: A total of 259 metabolites based on gallic acid and 112 metabolites based on catechins were identified. Among these, the peak areas of 157 gallic acid and 81 catechins gradually decreased, those of another 71 gallic acid and 30 catechins first increased and then decreased, those of 14 gallic acid and 1 catechin gradually increased. However, 17 of the gallic acids showed no significant changes. We speculate that many gallic acid metabolites hydrolyze to produce gallic acid; moreover, the dimers/trimers of catechins, after being cleaved into catechins, epicatechin, gallic acid catechins, and epicatechin monomers, are cleaved into gallic acid and protocatechualdehyde under high temperature and high humidity, subsequently participating in the Maillard reaction and browning reactions.Discussion: We showed that processing led to changes in chemical groups, clarification of the groups of secondary metabolites could provide a basis for research on the pharmacological and toxic mechanisms of RM, as well as the screening of related markers.

Generally, chloroplast genomes of angiosperms are always highly conserved but carry a certain number of variation among species. In this study, chloroplast genomes of 13 species from Datureae tribe that are of importance both in ornamental gardening and medicinal usage were studied. In addition, seven chloroplast genomes from Datureae together with two from Solanaceae species retrieved from the National Center for Biotechnology Information (NCBI) were integrated into this study. The chloroplast genomes ranged in size from 154,686 to 155,979 and from 155,497 to 155,919 bp for species of Datura and Brugmansia, respectively. As to Datura and Brugmansia, a total of 128 and 132 genes were identified, in which 83 and 87 protein coding genes were identified, respectively; Furthermore, 37 tRNA genes and 8 rRNA genes were both identified in Datura and Brugmansia. Repeats analysis indicated that the number and type varied among species for Simple sequence repeat (SSR), long repeats, and tandem repeats ranged in number from 53 to 59, 98 to 99, and 22 to 30, respectively. Phylogenetic analysis based on the plastid genomes supported the monophyletic relationship among Datura and Brugmansia and Trompettia, and a refined phylogenic relationships among each individual was resolved. In addition, a species-specific marker was designed based on variation spot that resulted from a comparative analysis of chloroplast genomes and verified as effective maker for identification of D. stramonium and D. stramonium var. inermis. Interestingly, we found that 31 genes were likely to be under positive selection, including genes encoding ATP protein subunits, photosystem protein subunit, ribosome protein subunits, NAD(P)H dehydrogenase complex subunits, and clpP, petB, rbcL, rpoCl, ycf4, and cemA genes. These genes may function as key roles in the adaption to diverse environment during evolution. The diversification of Datureae members was dated back to the late Oligocene periods. These chloroplast genomes are useful genetic resources for taxonomy, phylogeny, and evolution for Datureae.