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Rehmannia japonica (Thunb.) Makino ex T. Yamaz. is an endangered perennial herb species in Japan. Although earlier the Japanese considered it a variety of R. glutinosa, recent Japanese taxonomists have consistently regarded it as an independent species. According to the historical literature, Rehmannia japonica seems to have been known in China and Japan in the past. However, Chinese taxonomists do not recognize R. japonica at present. In Japan, only two populations are known, and although these populations flower every year, seed reproduction has not been observed. In this study, we aimed to reveal the phylogenetic relationships and levels of genetic diversity of R. japonica. A haplotype network based on two chloroplast DNA regions ( trnL- trnF and rps16) showed that the sequences of R. japonica were distinguishable by three or four sites of indels from the most closely related species, R. chingii, consistent with the separate species status of R. japonica. An analysis of genetic diversity using twelve microsatellite loci showed that all of the ramets of R. japonica collected from two geographically isolated populations had an identical multilocus genotype, including identical heterozygous genotypes at six loci. This result indicated asexual origin of all sampled ramets. This study also suggests that the absence of sexual reproduction of R. japonica is explained by self-incompatibility combined with only a single genet remaining in the R. japonica populations. [ABSTRACT FROM AUTHOR]

Neolitsea sericea (Lauraceae), endemic to East Asian land-bridge islands, is an economically important tree species because of its characteristic aroma and timber uses. However, due to the lack of efficient molecular markers, the genetic diversity and historical demography of this endemic species is not clearly understood. In this study, we performed high-throughput transcriptome sequencing of N. sericea leaves using the Illumina HiSeq™ 2000 sequencing platform, and generated large transcript sequences for functional characterization and development of gene-associated SSR markers. A total of 68,624 unigenes (mean length 733 bp) were assembled from about 54.7 million reads, and 41,130 (59.94 %) unigenes of all the assembled unigenes showed similarity to public databases. From 68,624 unigenes, 13,213 expressed sequence tag–simple sequence repeats (EST-SSRs) were identified. Di-nucleotide SSRs were the most abundant motif (36.5 %), followed by mono- (32.3 %) and tri-nucleotide (26.5 %) repeats. From the 13,213 EST-SSRs, 1191 primer pairs were designed for marker mining. After selecting 131 of these pairs at random for further validation, 13 polymorphic pairs were identified as polymorphic SSR loci. These 13 EST-SSR markers showed intermediate levels of genetic diversity (e.g., NA = 7.15; mean HE = 0.51) when surveyed across six populations from East China (2), Taiwan (1), Korea (1), and the Ryukyus (1) and Honshu (1) of Japan. Both genetic distance and structure analyses identified two genetic clusters largely congruent with recent findings revealed by variations in chloroplast DNA sequences and genomic SSRs. The EST-SSR markers developed in our research will be an information resource for future studies on ecological, evolutionary, and conservation genomics in N. sericea. [ABSTRACT FROM AUTHOR]

Dysosma (Berberidaceae), which comprises seven herbaceous perennial species, has long been used as main sources of a traditional Chinese medicine, 'Guijiu.' Despite its ecological and economic importance, molecular research of Dysosma has lagged behind because of the shortcoming of molecular markers. In this study, a cDNA library of D. versipellis leaves was sequenced using the Illumina HiSeq™ 2000 sequencing system. A total of 44,855 nonredundant unigenes were assembled from 57.6 million reads, and 5,167 expressed sequence tag-simple sequence repeats (EST-SSRs) were identified in 4,536 unigenes. Trinucleotide motifs were the most common type, with a frequency of 43.7 % (2,260). Among the 5,167 EST-SSRs, 1,050 primer pairs were successfully designed. After selecting 80 of these pairs at random for further validation, 19 pairs were identified as true-to-type SSR loci, and 14 of those could reliably amplify polymorphic bands from 12 individuals of D. versipellis. These 14 EST-SSR markers showed high average genetic diversity (e.g., N = 6.29; H = 0.528), when surveyed across four D. versipellis populations, and were also transferable to almost all other Dysosma species, excepting one marker (four instead of six species). Finally, 11 polymorphic markers were chosen to provide insights into the population structure of D. versipellis and its presumed sister species, D. pleiantha. Both genetic distance and structure analyses identified two genetic clusters largely congruent with the current species classification. These findings indicate that the EST-SSRs examined can be used with confidence in future population genetic studies of both D. versipellis and D. pleiantha. [ABSTRACT FROM AUTHOR]

Sinocalycanthus chinensis, an endangered species endemic to China, is cultivated as an ornamental landscape tree in China. However, S. chinensis, Chimonanthus species and Calycanthus floridus are difficult to be distinguished in seedling market because of their similar morphological characters. In this study, ISSR (inter-simple sequence repeats) were applied to detect S. chinensis from its closely related species. A unique 748-bp band was found in all accessions of S. chinensis. SCAR (sequence characterized amplified regions) markers were created by cloning and sequencing the specific band, and designing a pair of primers to amplify the band of 748 bp. Diagnostic PCRs were performed using the primer pair with the total DNAs of S. chinensis, Chimonanthus species and C. floridus as templates, with only S. chinensis being able to be amplified. This amplification is not only rapid (results can be obtained in less than 3 h), but is also easy to perform. Hence it is a feasible method for identifying S. chinensis in seedling market. [ABSTRACT FROM AUTHOR]

Subtropical China harbours the world's most diverse temperate flora, but little is known about the roles of geographical and eco-climatic factors underlying the region's exceptionally high levels of species diversity and endemism. Here we address this key question by investigating the spatio-temporal and ecological processes of divergence within the Dysosma versipellis-pleiantha species complex, endemic to subtropical China. Our cpDNA phylogeny showed that this monophyletic group of understory herbs is derived from a Late Pliocene ancestor of the Qinghai-Tibetan Plateau (QTP)/Southwest China. Genetic and ENM data in conjunction with niche differentiation analyses support that the early divergence of D. versipellis and D. pleiantha proceeded through allo-peripatric speciation, possibly triggered by Early Pleistocene climate change, while subsequent climate-induced cycles of range contractions/expansions enhanced the eco-geographical isolation of both taxa. Furthermore, modelling of population-genetic data indicated that major lineage divergences within D. versipellis likely resulted from long-term allopatric population isolation in multiple localized refugia over the last glacial/interglacial periods, and which in turn fostered endemic species formation (D. difformis, D. majoensis) from within D. versipellis in Southwest China. These findings point to an overriding role of Quaternary climate change in triggering essentially allopatric (incipient) speciation in this group of forest-restricted plant species in subtropical China. [ABSTRACT FROM AUTHOR]