Chrysanthemum L. (Asteraceae-Anthemideae) is a genus with rapid speciation. It comprises about 40 species, most of which are distributed in East Asia. Many of these are narrowly distributed and habitat-specific. Considerable variations in morphology and ploidy are found in this genus. Some species have been the subjects of many studies, but the relationships between Chrysanthemum and its allies and the phylogeny of this genus remain poorly understood. In the present study, 32 species/varieties from Chrysanthemum and 11 from the allied genera were analyzed using DNA sequences of the single-copy nuclear CDS gene and seven cpDNA loci (psbA-trnH, trnC-ycf6, ycf6-psbM, trnY-rpoB, rpS4-trnT, trnL-F, and rpL16). The cpDNA and nuclear CDS gene trees both suggest that 1) Chrysanthemum is not a monophyletic taxon, and the affinity between Chrysanthemum and Ajania is so close that these two genera should be incorporated taxonomically; 2) Phaeostigma is more closely related to the Chrysanthemum+Ajania than other generic allies. According to pollen morphology and to the present cpDNA and CDS data, Ajania purpurea is a member of Phaeostigma. Species differentiation in Chrysanthemum appears to be correlated with geographic and environmental conditions. The Chinese Chrysanthemum species can be divided into two groups, the C. zawadskii group and the C. indicum group. The former is distributed in northern China and the latter in southern China. Many polyploid species, such as C. argyrophyllum, may have originated from allopolyploidization involving divergent progenitors. Considering all the evidence from present and previous studies, we conclude that geographic and ecological factors as well as hybridization and polyploidy play important roles in the divergence and speciation of the genus Chrysanthemum.

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SummaryQuaternary climatic oscillations greatly influenced the distribution and pattern of biodiversity in the Northern Hemisphere. Here we examine how such oscillations in South East Asia may have affected the demographic and evolutionary history of a polyploid plant complex associated with semi-dry habitats.We analyzed plastid and nuclear ribosomal DNA (rDNA) internal transcribed spacer (ITS) sequence variation within the Chrysanthemum indicum complex (Asteraceae), which comprises diploid and polyploid plants distributed throughout China. In total, 368 individuals from 47 populations across the geographical range of the complex were analyzed.We show that the relatively widespread tetraploid form of C. indicum expanded its range southward in the Pleistocene, possibly during the most recent or previous glacial period when conditions became drier and forests retreated in southern China. In marked contrast, diploid and other polyploid members of the complex failed to expand their ranges at these times or have since undergone range contractions in contrast to tetraploid C. indicum.We conclude that hybridization and gene flow between taxa occurred frequently during the evolutionary history of the complex, causing considerable sharing of chlorotypes and ITS types. Nevertheless, taxa within ploidy levels could be largely distinguished according to chlorotype and/or ITS type.

Chemoresistance is a major barrier to successful cisplatin-based chemotherapy for epithelial ovarian cancer (EOC), and emerging evidences suggest that microRNAs (miRNAs) are involved in the resistance. In this study, it was indicated that miR-363 downregulation was significantly correlated with EOC carcinogenesis and cisplatin resistance. Moreover, miR-363 overexpression could resensitise cisplatin-resistant EOC cells to cisplatin treatment both in vitro and in vivo. In addition, data revealed that EMT inducer Snail was significantly upregulated in cisplatin-resistant EOC cell lines and EOC patients and was a functional target of miR-363 in EOC cells. Furthermore, snail overexpression could significantly attenuate miR-363-suppressed cisplatin resistance of EOC cells, suggesting that miR-363-regulated cisplatin resistance is mediated by snail-induced EMT in EOC cells. Taken together, findings suggest that miR-363 may be a biomarker for predicting responsiveness to cisplatin-based chemotherapy and a potential therapeutic target in EOC.