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Myripnois is a monotypic shrub genus in the daisy family constricted to northern China. Although wild populations of Myripnois dioica are relatively rare, this plant may potentially be cultured as a fine ornamental. In the present study, we sequenced the complete plastome of M. dioica, generating the first plastome sequences of the subfamily Pertyoideae. The plastome of M. dioica has a typical quadripartite circular structure. A large ∼20-kb and a small ∼3-kb inversion were detected in the large single copy (LSC) region and shared by other Asteraceae species. Plastome phylogenomic analyses based on 78 Asteraceae species and three outgroups revealed four groups, corresponding to four Asteraceae subfamilies: Asteroideae, Cichorioideae, Pertyoideae and Carduoideae. Among these four subfamilies, Pertyoideae is sister to Asteroideae + Cichorioideae; Carduoideae is the most basal clade. In addition, we characterized 13 simple sequence repeats (SSRs) that may be useful in future studies on population genetics. Keywords: Myripnois, Asteraceae, Plastomes, Large inversion, Phylogenomic analyses

Abstract Background Saussurea DC. is one of the largest and most morphologically heterogeneous genera in Asteraceae. The relationships within Saussurea have been poorly resolved, probably due an early, rapid radiation. To examine plastome evolution and resolve backbone relationships within Saussurea, we sequenced the complete plastomes of 17 species representing all four subgenera. Results All Saussurea plastomes shared the gene content and structure of most Asteraceae plastomes. Molecular evolutionary analysis showed most of the plastid protein-coding genes have been under purifying selection. Phylogenomic analyses of 20 Saussurea plastomes that alternatively included nucleotide or amino acid sequences of all protein-coding genes, vs. the nucleotide sequence of the entire plastome, supported the monophyly of Saussurea and identified three clades within it. Three of the four traditional subgenera were recovered as paraphyletic. Seven plastome regions were identified as containing the highest nucleotide variability. Conclusions Our analyses reveal both the structural conservatism and power of the plastome for resolving relationships in congeneric taxa. It is very likely that differences in topology among data sets is due primarily to differences in numbers of parsimony-informative characters. Our study demonstrates that the current taxonomy of Saussurea is likely based at least partly on convergent morphological character states. Greater taxon sampling will be necessary to explore character evolution and biogeography in the genus. Our results here provide helpful insight into which loci will provide the most phylogenetic signal in Saussurea and Cardueae.

Abstract Background Among the 13 families of early-diverging eudicots, only Circaeasteraceae (Ranunculales), which consists of the two monotypic genera Circaeaster and Kingdonia, lacks a published complete plastome sequence. In addition, the phylogenetic position of Circaeasteraceae as sister to Lardizabalaceae has only been weakly or moderately supported in previous studies using smaller data sets. Moreover, previous plastome studies have documented a number of novel structural rearrangements among early-divergent eudicots. Hence it is important to sequence plastomes from Circaeasteraceae to better understand plastome evolution in early-diverging eudicots and to further investigate the phylogenetic position of Circaeasteraceae. Results Using an Illumina HiSeq 2000, complete plastomes were sequenced from both living members of Circaeasteraceae: Circaeaster agrestis and Kingdonia uniflora . Plastome structure and gene content were compared between these two plastomes, and with those of other early-diverging eudicot plastomes. Phylogenetic analysis of a 79-gene, 99-taxon data set including exemplars of all families of early-diverging eudicots was conducted to resolve the phylogenetic position of Circaeasteraceae. Both plastomes possess the typical quadripartite structure of land plant plastomes. However, a large ~49 kb inversion and a small ~3.5 kb inversion were found in the large single-copy regions of both plastomes, while Circaeaster possesses a number of other rearrangements, particularly in the Inverted Repeat. In addition, infA was found to be a pseudogene and accD was found to be absent within Circaeaster, whereas all ndh genes, except for ndhE and ndhJ, were found to be either pseudogenized (ΨndhA, ΨndhB, ΨndhD, ΨndhH and ΨndhK) or absent (ndhC, ndhF, ndhI and ndhG) in Kingdonia. Circaeasteraceae was strongly supported as sister to Lardizabalaceae in phylogenetic analyses. Conclusion The first plastome sequencing of Circaeasteraceae resulted in the discovery of several unusual rearrangements and the loss of ndh genes, and confirms the sister relationship between Circaeasteraceae and Lardizabalaceae. This research provides new insight to characterize plastome structural evolution in early-diverging eudicots and to better understand relationships within Ranunculales .

Actinidia eriantha Benth. is a diploid perennial woody vine native to China and is recognized as a valuable species for commercial kiwifruit improvement with high levels of ascorbic acid as well as having been used in traditional Chinese medicine. Due to the lack of genomic resources for the species, microsatellite markers for population genetics studies are scarce. In this study, RNASeq was conducted on fruit tissue of A. eriantha, yielding 5,678,129 reads with a total output of 3.41 Gb. De novo assembly yielded 69,783 non-redundant unigenes (41.3 Mb), of which 21,730 were annotated using protein databases. A total of 8,658 EST-SSR loci were identified in 7,495 unigene sequences, for which primer pairs were successfully designed for 3,842 loci (44.4%). Among these, 183 primer pairs were assayed for PCR amplification, yielding 69 with detectable polymorphism in A. eriantha. Additionally, 61 of the 69 polymorphic loci could be successfully amplified in at least one other Actinidia species. Of these, 14 polymorphic loci (mean NA = 6.07 ± 2.30) were randomly selected for assessing levels of genetic diversity and population structure within A. eriantha. Finally, a neighbor-joining tree and Bayesian clustering analysis showed distinct clustering into two groups (K = 2), agreeing with the geographical distributions of these populations. Overall, our results will facilitate further studies of genetic diversity within A. eriantha and will aid in discriminating outlier loci involved in local adaptation.

Stephania is the sole genus in the basal eudicot family Menispermaceae that possesses both actinomorphic and zygomorphic flowers. Variation in perianth merism can have an important impact on flower symmetry and thus eminent biological significance in evolution of Menispermaceae. Using SEM, we studied the floral development of four representative species, which present the two predominant floral patterns of the genus, namely, homomorphy of both male and female flowers (actinomorphy) or heteromorphy (actinomorphy/ zygomorphy). The sepals of the male flowers are arranged mostly in two alternate whorls of three or four each, whereas in female flowers they are in a single whorl of three or four or there is only a single sepal. Petals of male flowers are in a whorl of three or four organs, whereas female flowers of some species have only two petals. Trimerous and tetramerous perianths can coexist in the same umbellets of some species. Variation in perianth merism and loss of perianth parts of the female flowers may result in flower symmetry switching from actinomorphy to zygomorphy. The two main floral patterns are consistent with a distinction of two subclades within Stephania. The unicarpellate genera of the Menispermaceae share a unique combination of characters, including a synandrium, unitegmic ovules, and absence of vestigial sexual organs. However, Stephania differs from its unicarpellate relatives by two features: a two-whorled arrangement of floral organs of the male flowers and a free perianth. The investigation provides new and valuable developmental information on flowers of the little-known Menispermaceae and provides a background for a discussion of the evolution of merism and unisexual flowers in the basal eudicots. [ABSTRACT FROM AUTHOR]

Floral ontogeny of two dioecious species in the Menispermaceae, Cocculus orbiculatus and Stephania dielsiana, was compared using scanning electron microscopy (SEM). In C. orbiculatus, flowers exhibit rudiments of a nonfunctional organ of the opposite sex. Female flowers have six stamens that remain primordial; however, male flowers usually have three carpellodes rather than six, and hence have a different number of carpels than female flowers. Development of carpellodes in the family was described under SEM for the first time. The male and female of C. orbiculatus are almost homomorphic in early developmental stages, with eight alternating whorls of four types of organs (sepals, petals, stamens/staminodes, and carpels/carpellodes) arising centripetally. In S. dielsiana, no vestigial sexual organs were found, and the symmetry of male and female flowers differs, with males being actinomorphic and females zygomorphic. The six stamens of C. orbiculatus are free, whereas the three or four stamens of S. dielsiana are united congenitally. There are six carpels in females of C. orbiculatus but a single one in S. dielsiana. In overview, all flowers are actinomorphic and trimerous, with the female flower of S. dielsiana being the exception. This may be the result of reduction and is yet to be determined. [ABSTRACT FROM AUTHOR]