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Premise: The proportion of polyploid plants in a community increases with latitude, and different hypotheses have been proposed about which factors drive this pattern. Here, we aimed to understand the historical causes of the latitudinal polyploidy gradient using a combination of ancestral state reconstruction methods. Specifically, we assessed whether (1) polyploidization enables movement to higher latitudes (i.e., polyploidization precedes occurrences in higher latitudes) or (2) higher latitudes facilitate polyploidization (i.e., occurrence in higher latitudes precedes polyploidization). Methods: We reconstructed the ploidy states and ancestral niches of 1032 angiosperm species at four paleoclimatic time slices ranging from 3.3 million years ago to the present, comprising taxa from four well‐represented clades: Onagraceae, Primulaceae, Solanum (Solanaceae), and Pooideae (Poaceae). We used ancestral niche reconstruction models alongside a customized discrete character evolution model to allow reconstruction of states at specific time slices. Patterns of latitudinal movement were reconstructed and compared in relation to inferred ploidy shifts. Results: No single hypothesis applied equally well across all analyzed clades. While significant differences in median latitudinal occurrence were detected in the largest clade, Poaceae, no significant differences were detected in latitudinal movement in any clade. Conclusions: Our preliminary study is the first to attempt to connect ploidy changes to continuous latitudinal movement, but we cannot favor one hypothesis over another. Given that patterns seem to be clade‐specific, more clades must be analyzed in future studies for generalities to be drawn. [ABSTRACT FROM AUTHOR]

Premise: The scents of volatile organic compounds (VOCs) are an important component of ripe fleshy fruit attractiveness, yet their variation across closely related wild species is poorly understood. Phylogenetic patterns in these compounds and their biosynthetic pathways offer insight into the evolutionary drivers of fruit diversity, including whether scent can communicate an honest signal of nutrient content to animal dispersers. We assessed ripe fruit VOC content across the tomato clade (Solanum sect. Lycopersicon), with implications for crop improvement since these compounds are key components of tomato flavor. Methods: We analyzed ripe fruit volatiles from 13 species of wild tomato grown in a common garden. Interspecific variations in 66 compounds and their biosynthetic pathways were assessed in 32 accessions, and an accession‐level phylogeny was constructed to account for relatedness. Results: Wild tomato species can be differentiated by their VOCs, with Solanum pennellii notably distinct. Phylogenetic conservatism exists to a limited extent. Major cladewide patterns corresponded to divergence of the five brightly colored‐fruited species from the nine green‐fruited species, particularly for nitrogen‐containing compounds (higher in colored‐fruited) and esters (higher in green‐fruited), the latter appearing to signal a sugar reward. Conclusions: We established a framework for fruit scent evolution studies in a crop wild relative system, showing that each species in the tomato clade has a unique VOC profile. Differences between color groups align with fruit syndromes that could be driven by selection from frugivores. The evolution of colored fruits was accompanied by changes in biosynthetic pathways for esters and nitrogen‐containing compounds, volatiles important to tomato flavor. [ABSTRACT FROM AUTHOR]

Premise: Whole‐genome duplication is considered a major mechanism of sympatric speciation due to the creation of strong and instantaneous reproductive barriers. Although postzygotic reproductive isolation between diploids and polyploids is often expected, the extent of reproductive incompatibility must be empirically determined and compared to patterns of genetic isolation to fully characterize the reproductive dynamics between cytotypes. Methods: We investigated reproductive compatibility between diploid and tetraploid Lycium australe in two mixed‐cytotype populations using (1) controlled crossing experiments to evaluate fruit and seed production and (2) germination trials to test seed viability following homoploid and heteroploid crosses. We contrast these experiments with a single‐nucleotide polymorphism (SNP) data set to measure genetic isolation between cytotypes and explore whether cytotype or population origin better explains patterns of genetic variation. Finally, we explore mating patterns using the observed germination rates of naturally produced seeds in each population. Results: Although homoploid and heteroploid crosses resulted in similar fruit and seed production, reproductive isolation between co‐occurring diploids and tetraploids was nearly complete, due to low seed viability following heteroploid crosses. Of 191,182 total SNPs, 21,679 were present in ≥90% of individuals and replicate runs using unlinked SNPs revealed strong clustering by cytotype and differentiation of tetraploids based on population origin. Conclusions: As often reported, diploid and tetraploid L. australe experience strong postzygotic isolation via hybrid seed inviability. Consistent with this result, cytotype explained a greater amount of variation in the SNP data set than population origin, despite some evidence of historical introgression. [ABSTRACT FROM AUTHOR]

Premise: Floral orientation is central to plant–pollinator interactions and is commonly associated with floral symmetry. Bilaterally symmetrical flowers are often oriented horizontally for optimal pollinator positioning and pollen transfer efficiency, while the orientation of radially symmetrical flowers is variable. Buzz‐pollinated species (pollinated by vibration‐producing bees) include bilateral, horizontally oriented flowers, and radial, pendant flowers. The effect of floral orientation on pollen transfer has never been tested in buzz‐pollinated species. Methods: Here, we examined the effect of floral orientation on bumblebee‐mediated pollen deposition in three buzz‐pollinated Solanum species with different floral symmetry and natural orientations: S. lycopersicum and S. seaforthianum (radial, pendant), and S. rostratum (bilateral, horizontal). We tested whether orientation affects total stigmatic pollen deposition (both self and outcross pollen) when all flowers have the same orientation (either pendant or horizontal). In a second experiment, we evaluated whether different orientations of donor and recipient flowers affects the receipt of outcross pollen by S. rostratum. Results: For the three Solanum species studied, there was no effect of floral orientation on total pollen deposition (both self and outcross) when flowers shared the same orientation. In contrast, in our experiment with S. rostratum, we found that pendant flowers received fewer outcross‐pollen grains when paired with pendant donors. Conclusions: We suggest that floral orientation influences the quality of pollen transferred, with more outcross pollen transferred to horizontally oriented recipients in the bilaterally symmetrical S. rostratum. Whether other bilaterally symmetrical, buzz‐pollinated flowers also benefit from increased cross‐pollination when presented horizontally remains to be established. [ABSTRACT FROM AUTHOR]

Premise: The inflorescences of Solanaceae are unique and complex, which has led to long‐standing disputes over floral symmetry mainly due to different interpretations of the cyme‐like inflorescence structure. The main disagreements have been over how the phyllomes associated with the flower were arranged relative to the inflorescence axis especially during early flower initiation. Methods: Here we investigated the evolution of inflorescences in Solanaceae by analyzing inflorescence structure in the context of phylogeny using ancestral state reconstruction (ASR) to determine the evolutionary transitions between loosely arranged and tightly clustered inflorescences and between monochasial‐like and dichasial‐like cymes. We also reconstructed two‐ and three‐dimensional models for 12 solanaceous species that represent both inflorescence and phylogenetic diversity in the family. Results: Our results indicate that the most recent common ancestor of Solanaceae had a loosely arranged and monochasial‐like cyme, while tightly clustered inflorescences and dichasial‐like cymes were derived. Compared to the known process of scorpioid cyme evolution, Solanaceae achieved their scorpioid cyme‐like inflorescences through a previously undescribed way. Along the pedicel, the two flower‐preceding prophylls are not in the typical transverse position of dicotyledonous plants; they frequently have axillary buds, and the main inflorescence axis continues in a sympodial fashion. As a result, the plane of symmetry of the flower is 36° from the median, and the inflorescence axis and the two flower‐preceding prophylls are symmetrically located along that plane. Conclusions: A better understanding of the morphological evolution of solanaceous inflorescence structure helped clarify the floral symmetry of Solanaceae. [ABSTRACT FROM AUTHOR]

Premise: Evolutionary studies require solid phylogenetic frameworks, but increased volumes of phylogenomic data have revealed incongruent topologies among gene trees in many organisms both between and within genomes. Some of these incongruences indicate polytomies that may remain impossible to resolve. Here we investigate the degree of gene‐tree discordance in Solanum, one of the largest flowering plant genera that includes the cultivated potato, tomato, and eggplant, as well as 24 minor crop plants. Methods: A densely sampled species‐level phylogeny of Solanum is built using unpublished and publicly available Sanger sequences comprising 60% of all accepted species (742 spp.) and nine regions (ITS, waxy, and seven plastid markers). The robustness of this topology is tested by examining a full plastome dataset with 140 species and a nuclear target‐capture dataset with 39 species of Solanum (Angiosperms353 probe set). Results: While the taxonomic framework of Solanum remained stable, gene tree conflicts and discordance between phylogenetic trees generated from the target‐capture and plastome datasets were observed. The latter correspond to regions with short internodal branches, and network analysis and polytomy tests suggest the backbone is composed of three polytomies found at different evolutionary depths. The strongest area of discordance, near the crown node of Solanum, could potentially represent a hard polytomy. Conclusions: We argue that incomplete lineage sorting due to rapid diversification is the most likely cause for these polytomies, and that embracing the uncertainty that underlies them is crucial to understand the evolution of large and rapidly radiating lineages. [ABSTRACT FROM AUTHOR]

Premise: Five to six percent of angiosperm species exhibit a dioecious sexual system, with unisexual "male" or "female" flowers borne on separate plants. The consequent need for inter‐individual pollen exchange is a special challenge for taxa where pollen is the sole pollinator reward. Dioecious Australian Solanum assure visits from pollen‐foraging bees via production of inaperturate pollen in functionally female (morphologically bisexual) flowers. Biochemical composition of pollen from Australian Solanum has not been assessed nor compared to porate pollen from staminate flowers to reveal whether these flowers differ in their pollinator reward potential. Methods: Porate pollen from male flowers and inaperturate pollen from functionally female flowers of two functionally dioecious Australian species were compared for protein and amino acid content. We also assessed pollen from bisexual and staminate flowers of a closely related andromonoecious species, in which all pollen is porate, as a comparison across co‐occurring sexual systems. Results: In both functionally dioecious species, porate pollen grains from staminate flowers had significantly higher levels of proteins and amino acids than inaperturate pollen grains from functionally female flowers. Levels of proteins and amino acids were highest in bisexual and staminate flowers of the andromonoecious species. Conclusions: Higher levels of proteins and amino acids in porate pollen of "male" flowers in our functionally dioecious Solanum species suggests a greater nutritive reward for bees foraging on "male" plants than for those foraging on functionally "female" plants. Greater reward in porate pollen (including andromonoecious species) may be connected to the potential to generate a pollen tube. [ABSTRACT FROM AUTHOR]

Premise: Long‐distance dispersal has been important in explaining the present distributions of many plant species. Despite being infrequent, such dispersal events have considerable evolutionary consequences, because bottlenecks during colonization can result in reduced genetic diversity. We examined the phylogeographic history of Lycium carolinianum, a widespread taxon that ranges from southeastern North America to several Pacific islands, with intraspecific diversity in sexual and mating systems. Methods: We used Bayesian, likelihood, and coalescent approaches with nuclear and plastid sequence data and genome‐wide single nucleotide polymorphisms to reconstruct the dispersal history of this species. We also compared patterns of genetic variation in mainland and island populations using single nucleotide polymorphisms and allelic diversity at the S‐RNase mating system gene. Results: Lycium carolinianum is monophyletic and dispersed once from the North American mainland, colonizing the Pacific islands ca. 40,100 years ago. This dispersal was accompanied by a loss of genetic diversity in SNPs and the S‐RNase locus due to a colonization bottleneck and the loss of self‐incompatibility. Additionally, we documented at least two independent transitions to gynodioecy: once following the colonization of the Hawaiian Islands and loss of self‐incompatibility, and a second time associated with polyploidy in the Yucatán region of Mexico. Conclusions: Long‐distance dispersal via fleshy, bird dispersed fruits best explains the unusually widespread distribution of L. carolinianum. The collapse of diversity at the S‐RNase locus in island populations suggests that self‐fertilization may have facilitated the subsequent colonization of Pacific islands following a single dispersal from mainland North America. [ABSTRACT FROM AUTHOR]

Premise: Common taxonomic practices, which condition species' descriptions on diagnostic morphological traits, may systematically lump outcrossing species and unduly split selfing species. Specifically, higher effective population sizes and genetic diversity of obligate outcrossers are expected to result less reliable phenotypic diagnoses. Wild tomatoes, members of Solanum sect. Lycopersicum, are commonly used as a source of exotic germplasm for improvement of the cultivated tomato, and are increasingly employed in basic research. Although the section experienced significant early work, which continues presently, the taxonomic status of many wild species has undergone a number of significant revisions and remains uncertain. Species in this section vary in their breeding systems, notably the expression of self‐incompatibility, which determines individual propensity for outcrossing Methods: Here, we examine the taxonomic status of obligately outcrossing Chilean wild tomato (Solanum chilense) using reduced‐representation sequencing (RAD‐seq), a range of phylogenetic and population genetic analyses, as well as analyses of crossing and morphological data. Results: Overall, each of our analyses provides a considerable weight of evidence that the Pacific coastal populations and Andean inland populations of the currently described Solanum chilense represent separately evolving populations, and conceal at least one undescribed cryptic species. Conclusions: Despite its vast economic importance, Solanum sect. Lycopersicon still exhibits considerable taxonomic instability. A pattern of under‐recognition of outcrossing species may be common, not only in tomatoes, but across flowering plants. We discuss the possible causes and implications of this observation, with a focus on macroevolutionary inference. [ABSTRACT FROM AUTHOR]

PREMISE: Inbreeding depression is well documented in flowering plants and adversely affects a wide range of fitness‐related traits. Recent work has begun to explore the effects of inbreeding on ecological interactions among plants and other organisms, including insect herbivores and pathogens. However, the effects of inbreeding on floral traits, floral scents, and pollinator visitation are less well studied. METHODS: Using inbred and outbred maternal families of horsenettle (Solanum carolinense, Solanaceae), we examined the effects of inbreeding on traits associated with pollinator attraction and floral rewards. Specifically, we measured corolla size, counted pollen grains per flower, and analyzed floral volatile emissions via gas chromatography and mass spectrometry. We also examined pollinator visitation to experimental arrays of flowering inbred and outbred plants under field conditions. RESULTS: Compared to those of outbred plants, flowers of inbred plants exhibited reduced corolla size and pollen production, as well as significantly reduced emission of the two most abundant volatile compounds in the floral blend. Furthermore, bumblebees—the main pollinators of horsenettle—discriminated against inbred flowers in the field: bees were more likely to make initial visits to flowers on outbred plants, visited outbred flowers more often overall, and spent more time on outbred flowers. CONCLUSIONS: These results show that inbreeding can (1) alter floral traits that are known to mediate pollinator attraction; (2) reduce the production of floral rewards (pollen is the sole reward in horsenettle); and (3) adversely affect pollinator visitation under field conditions. [ABSTRACT FROM AUTHOR]

Premise: Solanaceae is a scientifically and economically important angiosperm family with a minimal fossil record and an intriguing early evolutionary history. Here, we report a newly discovered fossil lantern fruit with a suite of features characteristic of Physalideae within Solanaceae. The fossil comes from the early Eocene Laguna del Hunco site (ca. 52 Ma) in Chubut, Argentina, which previously yielded the only other physaloid fruit fossil, Physalis infinemundi. Methods: The fruit morphology and calyx venation pattern of the new fossil were compared with P. infinemundi and extant species of Solanaceae. Results: Physalis hunickenii sp. nov. is clearly distinct from P. infinemundi in its fruiting calyx with wider primary veins, longer and thinner lobes, and especially in its venation pattern with high density, transverse tertiary veins; these features support its placement in a new species. In comparison with extant physaloid genera, the calyx venation pattern and other diagnostic traits reinforce placement of the new fossil, like P. infinemundi, within the tribe Physalideae of Solanaceae. Conclusions: Both species of fossil nightshades from Laguna del Hunco represent crown‐group Solanaceae but are older than all prior age estimates of the family. Although at least 20 transoceanic dispersals have been proposed as the driver of range expansion of Solanaceae, the Patagonian fossils push back the diversification of the family to Gondwanan times. Thus, overland dispersal across Gondwana is now a likely scenario for at least some biogeographic patterns, in light of the ancient trans‐Antarctic land connections between South America and Australia. [ABSTRACT FROM AUTHOR]

Premise: Pollen dispersal, the main component of overall plant gene flow, generally decreases with increasing distance from the pollen source, but the pattern of this relationship may differ among sites. Although site‐based differences in pollen dispersal may lead to over‐ or underestimation of gene flow, no studies have investigated pollen dispersal patterns among differing urban site types, despite the incongruent range of habitats in urban areas. Methods: We used paternity assignment to assess pollen dispersal patterns in a wind‐pollinated species (waterhemp; Amaranthus tuberculatus) and in an insect‐pollinated species (tomato; Solanum lycopersicum) in experimental arrays at four disparate sites (two roof‐level sites, two ground‐level sites) in the New York (New York, USA) metropolitan area. Results: The number of seeds or fruits, a proxy for the number of flowers pollinated, decreased with increasing distance from the pollen donors at all sites for both species. However, the mean number of Amaranthus tuberculatusseeds produced at a given distance differed two‐fold among sites, while the slope of the relationship between Solanum lycopersicumfruit production and distance differed by a factor of four among sites. Conclusions: Pollen dispersal patterns may differ substantially among sites, both in the amount of pollen dispersed at a given distance and in the proportional decrease in pollen dispersal with increasing distance, and these effects may act independently. Accordingly, the capacity of plant species to adapt to climate change and other selection pressures may be different from predictions based on pollen dispersal patterns at a single location. [ABSTRACT FROM AUTHOR]

Premise: Plant maternal effects on offspring phenotypes are well documented. However, little is known about how herbivory on maternal plants affects offspring fitness. Furthermore, while inbreeding is known to reduce plant reproductive output, previous studies have not explored whether and how such effects may extend across generations. Here, we addressed the transgenerational consequences of herbivory and maternal plant inbreeding on the reproduction of Solanum carolinense offspring. Methods: Manduca sexta caterpillars were used to inflict weekly damage on inbred and outbred S. carolinense maternal plants. Cross‐pollinations were performed by hand to produce seed from herbivore‐damaged outbred plants, herbivore‐damaged inbred plants, undamaged outbred plants, and undamaged inbred plants. The resulting seeds were grown in the greenhouse to assess emergence rate and flower production in the absence of herbivores. We also grew offspring in the field to examine reproductive output under natural conditions. Results: We found transgenerational effects of herbivory and maternal plant inbreeding on seedling emergence and reproductive output. Offspring of herbivore‐damaged plants had greater emergence, flowered earlier, and produced more flowers and seeds than offspring of undamaged plants. Offspring of outbred maternal plants also had greater seedling emergence and reproductive output than offspring of inbred maternal plants, even though all offspring were outbred. Moreover, the effects of maternal plant inbreeding were more severe when plant offspring were grown in field conditions. Conclusions: This study demonstrates that both herbivory and inbreeding have fitness consequences that extend across generations even in outbred progeny. [ABSTRACT FROM AUTHOR]

Premise: The distributions of plant clades are shaped by abiotic and biotic factors as well as historical aspects such as center of origin. Dispersals between distant areas may lead to niche evolution when lineages are established in new environments. Alternatively, dispersing lineages may exhibit niche conservatism, moving between areas with similar environmental conditions. Here we test these contrasting hypotheses in the Datureae clade (Solanaceae). Methods: We used maximum likelihood methods to estimate the ancestral range of Datureae along with the history of biogeographic events. We then characterized the niche of each taxon using climatic and soil variables and tested for shifts in environmental niche optima. Finally, we examined how these shifts relate to the niche breadth of taxa and clades within Datureae and the degree of overlap between them. Results: Datureae originated in the Andes and subsequently expanded its range to North America and non‐Andean regions of South America. The ancestral niche, and that of most Datura and Trompettia species, is dry, while Brugmansia species likely shifted toward a more mesic environment. Nonetheless, most Datureae present moderate to high overlap in niche breadth today. Conclusions: The expansion of Datureae into North America was associated with niche conservatism, with dispersal into similarly dry areas as occupied by the ancestral lineage. Subsequent niche evolution, including the apparent shift to a mesic niche in Brugmansia, diversified the range of habitats occupied by species in the tribe Datureae but also led to significant niche overlap among the three genera. [ABSTRACT FROM AUTHOR]

Premise: As Baker's law suggests, the successful colonization of oceanic islands is often associated with uniparental reproduction (self‐fertility), but the high incidence of dimorphism (dioecy, gynodioecy) on islands complicates this idea. Lycium carolinianum is widespread, occurring on the North American mainland and the Hawaiian Islands. We examined Baker's ideas for mainland and island populations of L. carolinianum and examined inbreeding depression as a possible contributor to the evolution of gynodioecy on Maui. Methods: Controlled crosses were conducted in two mainland populations and two populations in Hawaii. Treatments included self and cross pollination, unmanipulated controls, and autogamy/agamospermy. Alleles from the self‐incompatibility S‐RNase gene were isolated and compared between mainland and island populations. Given self‐compatibility in Hawaii, we germinated seeds from self‐ and cross‐ treatments and estimated inbreeding depression using seven traits and a measure of cumulative fitness. Results: Mainland populations of Lycium carolinianum are predominately self‐incompatible with some polymorphism for self‐fertility, whereas Hawaiian populations are self‐compatible. Concordantly, S‐RNase allelic diversity is reduced in Hawaii compared to the mainland. Hawaiian populations also exhibit significant inbreeding depression. Conclusions: Self‐compatibility in Hawaii and individual variation in self‐fertility in mainland populations suggests that a colonization filter promoting uniparental reproduction may be acting in this system. Comparison of S‐RNase variation suggests a collapse of allelic diversity and heterozygosity at the S‐RNase locus in Hawaii, which likely contributed to mate limitation upon arrival to the Pacific. Inbreeding depression coupled with autonomous self‐fertilization may have led to the evolution of gynodioecy on Maui. [ABSTRACT FROM AUTHOR]

Premise of the Study: While brinjal eggplant (Solanum melongena L.) is the second most important solanaceous fruit crop, we lack firm knowledge of its evolutionary relationships. This in turn limits efficient use of crop wild relatives in eggplant improvement. Here, we examine the hypothesis of linear step‐wise expansion of the eggplant group from Africa to Asia. Methods: We use museum collections to generate nuclear and full‐plastome data for all species of the Eggplant clade. We combine a phylogenomic approach with distribution data to infer a biogeographic scenario for the clade. Key Results: The Eggplant clade has Pleistocene origins in northern Africa. Dispersals to tropical Asia gave rise to Solanum insanum, the wild progenitor of the eggplant, and to African distinct lineages of widespread and southern African species. Results suggest that spread of the species to southern Africa has been recent and likely facilitated by large mammalian herbivores, such as the African elephant and impala feeding on Solanum fruit. Conclusions: Rather than a linear ‘Out Of Africa’ sequence, our results are more consistent with an initial dispersal event into Asia, and subsequent wide dispersal and differentiation across Africa driven by large mammalian herbivores. Our evolutionary results will affect future work on eggplant domestication and affect the use of wild relatives in breeding of this increasingly important solanaceous crop. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: Fossils provide minimum age estimates for extant lineages. Here we critically evaluate Cantisolanum daturoides Reid & Chandler and two other early putative seed fossils of Solanaceae, an economically important plant family in the Asteridae. METHODS: Three earliest seed fossil taxa of Solanaceae from the London Clay Formation (Cantisolanum daturoides) and the Poole and Branksome Sand Formations (Solanum arnense Chandler and Solanispermum reniforme Chandler) were studied using x-ray microcomputed tomography (MCT) and scanning electron microscopy (SEM). KEY RESULTS: The MCT scans of Cantisolanum daturoides revealed a high level of pyrite preservation at the cellular level. Cantisolanum daturoides can be clearly excluded from Solanaceae and has more affinities to the commelinid monocots based on a straight longitudinal axis, a prominent single layer of relatively thin-walled cells in the testa, and a clearly differentiated micropyle surrounded by radially elongated and inwardly curved testal cells. While the MCT scans show no internal preservation in Solanum arnense and Solanispermum reniforme, SEM images show the presence of several characteristics that allow the placement of these taxa at the stem node of Solanaceae. CONCLUSIONS: Cantisolanum daturoides is likely a member of commelinid monocots and not Solanaceae as previously suggested. The earliest fossil record of Solanaceae is revised to consist of fruit fossil with inflated calyces from the early Eocene of Patagonia (52 Ma) and fossilized seeds from the early to mid-Eocene of Europe (48-46 Ma). The new identity for Cantisolanum daturoides does not alter a late Cretaceous minimum age for commelinids. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: The species boundaries of wild and cultivated potatoes are controversial, with most of the taxonomic problems in the cultivated potato clade. We here provide the first in-depth phylogenetic study of the cultivated potato clade to explore possible causes of these problems. METHODS: We examined 131 diploid accessions, using 12 nuclear orthologs, producing an aligned data set of 14,072 DNA characters, 2171 of which are parsimony-informative. We analyzed the data to produce phylogenies and perform concordance analysis and goodness-of- fit tests. KEY RESULTS: There is good phylogenetic structure in clades traditionally referred to as clade 1+2 (North and Central American diploid potatoes exclusive of Solanum verrucosum), clade 3, and a newly discovered basal clade, but drastically reduced phylogenetic structure in clade 4, the cultivated potato clade. The results highlight a clade of species in South America not shown before, 'neocardenasii', sister to clade 1+2, that possesses key morphological traits typical of diploids in Mexico and Central America. Goodness-of- fit tests suggest potential hybridization between some species of the cultivated potato clade. However, we do not have enough phylogenetic signal with the data at hand to explicitly estimate such hybridization events with species networks methods. CONCLUSIONS: We document the close relationships of many of the species in the cultivated potato clade, provide insight into the cause of their taxonomic problems, and support the recent reduction of species in this clade. The discovery of the neocardenasii clade forces a reevaluation of a hypothesis that section Petota originated in Mexico and Central America. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: Self-incompatibility (SI) prevents self-fertilization and reduces inbreeding. While SI is common in plants, transitions to self-compatibility (SC) occur frequently. Little is known about the genetic changes and evolutionary steps underlying these shifts. METHODS: In the Solanaceae, SI is gametophytic, with specificity determined by S-RNases in the pistil and S-locus F-box proteins (SLFs) in pollen. We examined the role of two pollen factors, Cullin1 (CUL1) and SLF-23, in SI → SC transitions in wild tomato species from the Arcanum species group ( Solanum arcanum, S. neorickii, and S. chmielewskii). Pollen compatibility was assessed on tester lines that reject pollen lacking functional SLF-23 or CUL1. Complementation tests, gene sequencing, and phylogenetic analyses were used to characterize both functional and nonfunctional alleles. KEY RESULTS: We found evidence for multiple independent SI → SC transitions. In S. arcanum and S. chmielewskii, SC is caused by loss of pistil S-RNase activity, while in S. neorickii SC is associated with expression of a functional SLF-23 that recognizes the S9 type S-RNase expressed in its pistils. Interestingly, we found identical deletion mutations in CUL1 exon 7 of S. chmielewskii as previously seen in S. habrochaites. CONCLUSIONS: Mating system transitions in the Arcanum group have occurred via both pistil loss-of-function and pollen gain-of-function SC mutations. Mutations common to S. chmielewskii and S. habrochaites must have arisen in a common ancestor, possibly to the entire tomato clade, then became fixed in different lineages after loss of pistil-side SI function. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: Plant responses to past climate change could have been shaped by life-history traits. Here we explore the influence of life form on the response of xerophytic plants to Quaternary climate fluctuations, through a comparison of genetic patterns of codistributed herbaceous and shrubby lineages of the genus Nolana. METHODS: We reconstructed the phylogeographic history of a herbaceous lineage of three species of Nolana distributed from a northern arid zone (30°S) to a southern wet-temperate (42°S) zone, by sequencing two cpDNA regions. Results were compared with similar data published earlier for a congeneric, codistributed shrubby lineage. KEY RESULTS: We detected significant genetic differentiation among populations. Divergence of all haplotypes occurred during the Pleistocene, between 245 and 62 kyr ago. For both the shrubby and herbaceous lineages, the greatest haplotype diversity was found in their northern range. However, herbs also retained some diversity at higher latitude. Herbaceous populations were less genetically structured and less differentiated than shrubby ones. CONCLUSION: Genetic evidence revealed that both lineages of Nolana survived climate change through the Quaternary, experiencing population collapses and recoveries. Phylogeographic histories present similarities between the two lineages, but also marked differences that can be explained by their differences in life form and life cycle. While the shrubby lineage followed the classical pattern of postglacial expansion toward higher latitudes, species in the herbaceous lineage showed evidence of long-lasting persistence at the southern edge of their current range, suggesting for the first time multiple glacial refugia for a xerophytic plant in southern South America. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY:: Floral morphology is expected to evolve following the transition from cosexuality to gender dimorphism in plants, as selection through male and female function becomes dissociated. Specifically, male‐biased dimorphism in flower size can arise through selection for larger flowers through male function, selection for smaller flowers through female function, or both. The evolutionary pathway to floral dimorphism can be most effectively reconstructed in species with intraspecific variation in sexual system. We examined the evolution of flower size and shape in Lycium californicum, whose populations are either gender dimorphic with male and female plants, or cosexual with hermaphroditic plants. METHODS:: Floral morphology was characterized in populations spanning the species’ complete range. For a subset of the range where cosexual and dimorphic populations are in close proximity, we compared the size and shape of flowers from female and male plants in dimorphic populations to hermaphrodites in cosexual populations, accounting for variation associated with abiotic environmental conditions. KEY RESULTS:: The magnitude of flower size dimorphism varied across dimorphic populations. After controlling for environmental variation across cosexual and dimorphic populations, flowers on males were larger than flowers on females and hermaphrodites, whereas flower size did not differ between females and hermaphrodites. Flower shape differences were associated with mating type, sexual system, and environmental variation. CONCLUSIONS:: While abiotic environmental gradients shape both overall flower size and shape, male‐biased flower size dimorphism in L. californicum appears to arise through selection for larger flowers in males but not smaller flowers in females. [ABSTRACT FROM AUTHOR]

premise of the STUDY: Self-incompatibility (SI) is a mechanism that prevents inbreeding in many plant species. The mutational breakdown of SI occurs frequently, yet relatively little is known about the evolutionary steps involved in the progressive loss of pistil and pollen SI function. METHODS : In Solanaceae, SI is the S-RNase-based gametophytic type. We used SI and SC populations of the wild tomato species Solarium habrochaites to study natural variation for two pollen SI factors: a Cullinl (CUL1) protein and an S-locus F-box protein (SLF-23). Pollen compatibility was assessed on an allotriploid tester line encoding an S-RNase recognized by SLF-23. Both pollen factors are required for compatibility on this tester line. Complementation tests and gene sequencing were used to identify mutations in CUL1 or SLF-23. KEY RESULTS: We detected loss-of-function mutations in CUL1 and/or SLF-23 in SC populations collected near the northern and southern geographic margins of this taxon's natural range. Nonmarginal SC and all SI accessions expressed mostly functional alleles of these pollen factors. Comparison of the CUL 1 sequences identified several shared deletion mutations present in both northern and southern margin SC accessions.CONCLUSIONS: Loss-of-function mutations in CUL1 and SLF-23 likely became fixed relatively late during SI to SC transitions, after loss of pistil SI function. Mutations in CUL1 establish unilateral incompatibility with SI populations and strengthen reproductive isolation. Point mutations common to northern and southern SC biotypes likely derive from shared ancestral variants found in more central SI populations. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: Crop wild relatives (CWR) provide important traits for plant breeding, including pest, pathogen, and abiotic stress resistance. Therefore, their conservation and future availability are essential for food security. Despite this need, the world's genebanks are currently thought to conserve only a small fraction of the total diversity of CWR. METHODS: We define the eggplant genepool using the results of recent taxonomic and phylogenetic studies. We identify the gaps in germplasm accessions for eggplant {Solanum melongena L.) CWR by comparing georeferenced herbarium records and germplasm accessions using a gap analysis methodology implementing species distribution models (SDM). Preliminary conservation assessments using IUCN criteria were done for all species and were combined with the gap analysis to pinpoint where under-collected and threatened CWR species coincide with high human disturbance and occur outside of protected areas. KEY RESULTS: We show that many eggplant CWR are poorly represented in genebanks compared to their native ranges. Priority areas for future collecting are concentrated in Africa, especially along the Kenya-Tanzania border. Fourteen species of eggplant CWR are assessed as threatened or near-threatened; these are also concentrated in eastern Africa. CONCLUSIONS: The knowledge base upon which conservation of wild relative germplasm depends must take into account both taxonomic and phylogenetic advances. Beyond traditional research focus on close relatives of crops, we emphasize the benefits of defining a broad CWR genepool, and the importance of assessing threats to wild species when targeting localities for future collection of CWR to improve crop breeding in the face of environmental change. [ABSTRACT FROM AUTHOR]

* Premise of the study: Interspecific reproductive barriers (IRBs) act to ensure species integrity by preventing hybridization. Previous studies on interspecific crosses in the tomato clade have focused on the success of fruit and seed set. The SI x SC rule (SI species x SC species crosses are incompatible, but the reciprocal crosses are compatible) often applies to interspecific crosses. Because SI systems in the Solanaceae affect pollen tube growth, we focused on this process in a comprehensive study of interspecific crosses in the tomato clade to test whether the SI x SC rule was always followed. * Methods: Pollen tube growth was assessed in reciprocal crosses between all 13 species of the tomato clade using fluorescence microscopy. * Key results: In crosses between SC and SI species, pollen tube growth follows the SI x SC rule: interspecific pollen tube rejection occurs when SI species are pollinated by SC species, but in the reciprocal crosses (SC x SI), pollen tubes reach ovaries. However, pollen tube rejection occurred in some crosses between pairs of SC species, demonstrating that a fully functional SI system is not necessary for pollen tube rejection in interspecific crosses. Further, gradations in the strength of both pistil and pollen IRBs were revealed in interspecific crosses using SC populations of generally SI species. * Conclusion: The SI x SC rule explains many of the compatibility relations in the tomato clade, but exceptions occur with more recently evolved SC species and accessions, revealing differences in strength of both pistil and pollen IRBs. [ABSTRACT FROM AUTHOR]

* Premise of the study: White forms of typically pigmented flowers are one of the most common polymorphisms in flowering plants. Although the range of genetic changes that give rise to white phenotypes is well known from model systems, few studies have identified causative mutations in natural populations. * Methods: Here we combine genetic studies, in vitro enzyme assays, and biochemical analyses to identify the mechanism underlying the loss of anthocyanin pigment production in the naturally occurring white-flowered morph of Iochroma calycinum (Solanaceae). * Key results: Comparison of anthocyanin gene sequences revealed a putative loss-of-function mutation, an 11 amino-acid deletion in dihydroflavonol 4-reductase (DFR), in the white morph. Functional assays of Dfr alleles from blue and white morphs demonstrated that this deletion results in a loss of enzymatic activity, indicating that the deletion could be solely responsible for the lack of pigment production. Consistent with this hypothesis, quantitative PCR showed no significant differences in expression of anthocyanin genes between the morphs. Also, thin layer chromatography confirmed that the white morph continues to accumulate compounds upstream of the DFR enzyme. * Conclusions: Collectively, these experiments indicate that the structural mutation at Dfr underlies the rare white flower moiph of/, calycinum. This study is one of only a few examples where a flower color polymorphism is due to a loss-of-function mutation in the coding region of an anthocyanin enzyme. The rarity of such mutations in nature suggests that negative consequences prevent fixation across populations. [ABSTRACT FROM AUTHOR]

* Premise of the study: Crop wild relatives represent important genetic resources for crop improvement and the preservation of native biodiversity. Eggplant (Solatium melongena), known as brinjal in India, ranks high among crops whose wild gene pools are underrepresented in ex situ collections and warrant urgent conservation. Knowledge of outcrossing rates and patterns of genetic variation among wild populations can aid in designing strategies for both in situ and ex situ preservation. * Methods: We used 14 microsatellite (simple sequence repeat) markers to examine genetic diversity, population structure, and outcrossing in 10 natural populations of wild/weedy eggplant (S. insanum = S. melongena var. insanum) and three cultivated populations in southern India. * Key results: Multilocus FST analyses revealed strong differentiation among populations and significant isolation by distance. Bayesian model-based clustering, principal coordinate analysis, and hierarchical cluster analysis grouped the wild/weedy populations into three major clusters, largely according to their geographic origin. The three crop populations were similar to each other and grouped with two wild/weedy populations that occurred nearby. Outcrossing rates among the wild/weedy populations ranged from 5-33%, indicating a variable mixed-mating system. * Conclusion: Geographic isolation has played a significant role in shaping the contemporary patterns of genetic differentiation among these populations, many of which represent excellent candidates for in situ conservation. In two cases, close genetic affinity between cultivars and nearby wild/weedy populations suggests that gene flow has occurred between them. To our knowledge, this is the first study investigating population-level patterns of genetic diversity in wild relatives of eggplant. [ABSTRACT FROM AUTHOR]

Premise of the study: An association between polyploidy and gender dimorphism has been noted in several plant lineages. Whereas the majority of Lycium species are diploid and have hermaphroditic flowers in cosexual populations, gender dimorphism (gynodioecy, dioecy) has been shown to be uniformly associated with polyploidy m previous studies. Prelimmary fie observations suggested that some populations of Lycium carolinianum were dimorphic, providing a test of this association. • Methods : We assessed sexual systems and cytotype variation (to infer ploidy) across 17 populations of L. carolinianum. Comparison of flowers in cosexual and dimorphic populations were used to infer changes in reproductive morphology associated • Key results:The majority of populations were cosexual in gender expression, but dimorphism was present in the Yucatan and in some populations in Hawaii. Populations varied in ploidy and were either diploid or tetraploid. Floral sexual dimorphism was present in all gynodioecious populations, though the magnitude differed and was cryptic in some cases. Our results are consistent with the hypothesis that following the evolution of gynodioecy, flowers on hermaphrodites increased in size • Conclusions: Dimorphic sexual systems have likely evolved convergently in L. carolinianum. In contrast to previous studies, dimorphism is not perfectly associated with polyploidy. Although our sample from the Yucatan was both tetraploid and dimor phic, Til populations in Hawaii were diploid regardless of sexual system. Ongoing phylogeographic and mating system studies will contribute to our understanding of reproductive evolution in this widespread, polymorphic species. [ABSTRACT FROM AUTHOR]

Premise of the study: Complete chloroplast genome studies can help resolve relationships among large, complex plant lineages such as Asteraceae. We present the first whole plastome from the Madieae tribe and compare its sequence variation to other chloroplast genomes in Asteraceae. Methods: We used high throughput sequencing to obtain the Lasthenia burkei chloroplast genome. We compared sequence structure and rates of molecular evolution in the small single copy (SSC), large single copy (LSC), and inverted repeat (IR) regions to those for eight Asteraceae accessions and one Solanaceae accession. Key results: The chloroplast sequence of L burkei is 150746 bp and contains 81 unique protein coding genes and 4 coding ribosomal RNA sequences. We identified three major inversions in the L. burkei chloroplast, all of which have been found in other Asteraceae lineages, and a previously unreported inversion in Lactuca sativa. Regions flanking inversions contained tRNA sequences, but did not have particularly high G + C content. Substitution rates varied among the SSC, LSC, and IR regions, and rates of evolution within each region varied among species. Some observed differences in rates of molecular evolution may be explained by the relative proportion of coding to noncoding sequence within regions. Conclusions: Rates of molecular evolution vary substantially within and among chloroplast genomes, and major inversion events may be promoted by the presence of tRNAs. Collectively, these results provide insight into different mechanisms that may promote intramolecular recombination and the inversion of large genomic regions in the plastome. [ABSTRACT FROM AUTHOR]

* Premise of this study: The mediation of plant-insect interactions by plant odors has been studied extensively, but most previous work has focused on documenting the role of constitutive and herbivore- or pathogen-induced plant volatiles as foraging cues for insect herbivores and their natural enemies. Relatively little work has explored genotypic variation in plant-odor profiles within species, and few studies have addressed the perception and use of olfactory cues by lepidopteran larvae or other herbivores during feeding. *Methods: We examined the effects of plant breeding (inbred vs. outbred individuals) and plant exposure to prior herbivory on the preferences of caterpillars (Manduca sexta) for odors of Solanum carolinense in leaf-disc and whole-plant choice assays. * Key results: Second- and third-instar larvae of M. sexta clearly and consistently preferred undamaged over herbivore-damaged plants of both breeding types and also consistently preferred inbred over outbred plants that had the same damage status. Similar preferences were observed even when plants were covered with bridal-veil cloth to mask visual cues, demonstrating that olfactory cues influence larval preferences. * Conclusions: The observed preferences are consistent with our previous findings regarding the constitutive and induced volatile profiles of inbred and outbred horsenettle plants and their effects on plant-herbivore interactions. They furthermore correspond to differences in host-plant quality predicted by previous work and, thus, suggest that naive larvae of M. sexta can accurately assess aspects of host-plant quality via olfactory cues perceived at a distance. [ABSTRACT FROM AUTHOR]

* Premise of the study: The garden petunia is derived from Petunia axillaris (white flowered) and a purple-flowered species in the P. integrifolia group; it is still unclear which purple-flowered species was used in the initial crosses. This widely cultivated hybrid is an ideal model for different areas of scientific inquiry. * Methods: We analyzed three taxa of the P. integrifolia group considered to be the most probable parental candidates, along with a random sample of garden petunia representatives that were selected for their genetic variability. We used cpDNA tmH-psbA and trnS-trnG haplotypes and seven nuclear microsatellites in a population approach to investigate the genetic variability. This is the first time information from plastid DNA sequences and nuclear microsatellites has been combined to infer evolutionary relationships in these taxa. * Key results: Our results suggest that P. interior is the purple ancestor of garden petunias, and we postulate that the initial crosses must have been between both parents as a mother plant. * Conclusions: Our work will contribute to the clarification of the evolutionary relationships among the Petunia xhybrida and P. integrifolia taxa group and could be useful in breeding programs to transfer desired traits from wild to cultivated species. [ABSTRACT FROM AUTHOR]

* Premise of the study: Cultivated tomato, Solarium lycopersicum, suffers chilling induced wilting because water movement through its roots decreases with declining soil temperatures. Certain wild tomato species exhibit resistance to chilling-induced wilting, but the extent of this chilling tolerance in wild tomatoes is not known. * Methods: We measured shoot wilting during root chilling in wild Solarium accessions from habitats differing in elevation, temperature, and precipitation. We also measured shoot wilting during root chilling in introgression lines (ILs) with chromo some 9 segments collinear to the shoot turgor maintenance QTL stm9 region from chilling-tolerant S. habrochaites, chilling and drought-tolerant S. lycopersicoides, or drought-tolerant S. pennellii. * Key results: Wild tomato species, which experience chilling temperatures (<10°C) in their native habitat, maintain shoot turgor under root chilling. Among accessions of S. lycopersicum var. cerasiforme, a typically chilling sensitive species, shoot turgor maintenance during root chilling was correlated with the precipitation of the native habitat. By contrast, S. pennellii, a species that is typically drought adapted, did not maintain turgor under root chilling. Grafted plants with roots containing S. habrochaites and S. lycopersicoides introgressions improved shoot turgor maintenance under root chilling. * Conclusions: Resistance to chilling-induced water stress is an important adaptation to chilling temperatures in wild tomatoes. There is some overlap in adaptation to drought and chilling stress in some tomato species. Root-based resistance to chilling-induced water stress in wild tomatoes may involve orthologous gene(s). [ABSTRACT FROM AUTHOR]

* Premise of the study: For over a century, it has been hypothesized that selection can convert an environmentally induced phenotype (i.e., plasticity) into a fixed (constitutively produced) phenotype, a process known as genetic assimilation. While evidence of assimilation is accumulating, the role of plasticity generally and assimilation specifically in evolutionary diversification has rarely been examined from a comparative phylogenetic perspective. * Methods: We combined experimental analyses of plasticity with ancestral state reconstructions to examine the evolutionary dynamics of sexual expression in two well-chracterized sections (Acanthophora and Lasiocarpa) in Solanum subgenus Leptostemonum. We examined sexual expression phenotypes and the proportion of staminate flowers produced under contrasting resource conditions in 10 species and combined these data with previous studies. * Key results: Staminate flower production was phenotypically plastic for nine of 14 species and unaffected by treatment in five species. Two of the nonplastic species bore few staminate flowers, and three constitutively produced large numbers of staminate flowers. For individuals and species producing staminate flowers, these flowers occurred in a distinctive architectural pattern that was qualitatively the same in both plastic and nonplastic species. Parsimony and Bayesian reconstructions demonstrate that plasticity is ancestral among the species studied. * Conclusions: Plasticity has been lost independently in sections Acanthophora and Lasiocarpa, and the consequence of its loss results in evolutionary diversification of sexual expression. In section Acanthophora, loss of plasticity represents a reversion to production of predominantly hermaphroditic flowers. In contrast, the fixed production of staminate flowers in Lasiocarpa has the hallmarks of evolution via genetic assimilation. [ABSTRACT FROM AUTHOR]

* Premise of the study: A growing number of studies document effects of inbreeding on plant interactions with insect herbivores, including deleterious effects on direct and indirect plant defenses. However, our understanding of the specific mechanisms mediating such effects remains limited. Here we examine how inbreeding affects constitutive and induced expression of structural defenses (spines and trichomes) in common horsenettle. Solatium carolinense. * Methods: Inbred and outbred progeny from nine maternal families of horsenettle were assigned to three treatments: control, Manduca sexta caterpillar damage, or mechanical damage. Numbers of internode spines and the density of abaxial and adaxial trichomes were assessed before and after (21 d) damage treatments. Data on internode length, flowering time, and total flower production was also collected to explore the costs of defense induction. * Key results: Inbreeding adversely affected constitutive and induced physical/structural defenses: undamaged outbred plants produced more abaxial and adaxial leaf trichomes and internode spines than did inbred plants. Foliar damage by M. sexta larvae also induced more trichomes (on new leaves) and internode spines on outbred plants. Both inbred and outbred plants exposed to mechanical or caterpillar damage had shorter internodes than did control plants, but inbred damaged plants had longer inter- nodes than did outbred damaged plants. Control outbred plants produced significantly more flowers than did control inbred plants or damaged plants of either breeding type. * Conclusions: Constitutive and induced structural defenses in horsenettle were negatively affected by inbreeding. Reduced flower production and internode length on damaged plants compared to controls suggests that defense induction entails significant costs. [ABSTRACT FROM AUTHOR]

Premise: Plant defenses are shaped by many factors, including herbivory, lifespan, and mating system. Predictions about plant defense and resistance are often based on resource allocation trade-offs with plant growth and reproduction. Additionally, two types of plant resistance, constitutive and induced resistance, are predicted to be evolutionary alternatives or redundant strategies. Given the variety of plant trait combinations and non-mutually exclusive predictions, examining resistance strategies in related species with different combinations of growth and reproductive traits is important to tease apart roles of plant traits and evolutionary history on plant resistance., Methods: Phylogenetic comparative methods were used to examine the potentially interacting influences of life history (annual/perennial), mating system (self-compatible/self-incompatible), and species growth rates on constitutive resistance and inducibility (additional resistance following damage) across Physalis species (Solanaceae)., Results: Resistance was evolutionarily labile, and there was no correlation between constitutive resistance and inducibility. Annual species with fast growth rates displayed higher constitutive resistance, but growth rate did not affect constitutive resistance in perennials. In contrast, inducibility was negatively associated with species growth rate regardless of life history or mating system., Conclusions: The different effects of plant life history and growth rate on constitutive resistance and inducibility indicate that defensive evolution is unconstrained by a trade-off between resistance types. The interactions among plant life history, growth, and herbivore resistance show that plant defense is shaped not only by herbivore environment, but also by plant traits that reflect a plant's evolutionary history and local selective pressures., (© 2022 Botanical Society of America.)

Premise of the study: Wild relatives of crop species have long been viewed as an important genetic resource for crop improvement, but basic information about the population biology of these species is often lacking. This study investigated the population structure, demographic history, and evolutionary patterns of a green-fruited relative of the cultivated tomato, Solanum peruvianum. Methods: We investigated spatial genetics of S. peruvianum and screened for loci potentially under natural selection by integrating amplified fragment length polymorphism (AFLP) genotypes, phenotypic data, geography, and geographic information system (GIS)-derived climate data of 19 natural populations. Key results: Solanum peruvianum had a moderate degree of population differentiation, likely reflecting partial geographic isolation between species. Populations had a distribution pattern consistent with north-to-south "stepping-stone" dispersal with significant isolation by distance (IBD), similar to other tomato species. Several AFLP loci showed evidence of selection and associated with climate variables. However, phenotypic traits generally did not correlate with climate variables. Conclusions: Geographic features of the coastal Andes is likely an important factor that determines the migration pattern and population structure of S. peruvianum, but climatic factors do not appear to be critical for its phenotypic evolution, perhaps due to a high degree of phenotypic plasticity. Spatial genetics of wild relatives of crop species is a powerful approach to understand their evolutionary patterns and to accelerate the discovery of their potential for crop improvements. [ABSTRACT FROM AUTHOR]

* Premise of the study: Hybridization and polyploidization (allopolyploidy) are ubiquitous in the evolution of plants, but tracing the origins and subsequent evolution of the constituent genomes of allopolyploids has been challenging. Genome doubling greatly complicates genetic analyses, and this has long hindered investigation in that most allopolyploids species are "non-model" organisms. However, recent advances in sequencing and genomic technologies now provide unprecedented opportunities to analyze numerous genetic markers in multiple individuals in any organism.* Methods: Here we review the application of next-generation sequencing technologies to the study of three aspects of allopolyploids genome evolution: duplicated gene loss and expression in two recently formed Tragopogon allopolyploids, intergenomic interactions and chromosomal evolution in Tragopogon miscellus, and repetitive DNA evolution in Nicotiana allopolyploids. * Key results: For the first time, we can explore on a genomic scale the evolutionary processes that are ongoing in natural allopolyploids and not be restricted to well-studied crops and genetic models. * Conclusions: These approaches can be easily and inexpensively applied to many other plant species--making any evolutionarily provocative system a new "model" system. [ABSTRACT FROM AUTHOR]

* Premise of the study: The cyclotide kalata B1 is found in the leaves of Oldenlandia affinis and is a potent insecticidal and nematocidal molecule. This peptide is cleaved from a precursor protein, Oak1, and ligation of the N- and C-termini occurs to form a continuous peptide backbone. The subcellular location of the excision and cyclization reactions is unknown, and there is debate as to which enzyme catalyzes the event. To determine where in the plant cell Oak1 is processed, we prepared constructs encoding GFP (green fluorescent protein) linked to the cyclotide precursor Oak1. * Methods: The GFP constructs were transiently expressed in the leaves of Nicotiana benthamiana, and GFP fluorescence was observed in living cells using confocal microscopy. A Fei Mao (FM) styryl dye was infiltrated into whole leaves that were still growing and expressing GFP constructs, enabling the plasma membrane and the tonoplast to be highlighted for visualization of the vacuole in living cells. * Key results: The full length Oak1 precursor directed GFP to the vacuole, suggesting that excision and cyclization of the cyclotide domain occurs in the vacuole where the cyclotides are then stored. The N-terminal propeptide and N-terminal repeat of Oak1 were both sufficient to target GFP to the vacuole, although the C-terminal propeptide, which is essential for cyclization, was not a targeting signal. * Conclusions: The vacuolar location of cyclotides supports our hypothesis that the vacuolar processing enzyme, asparaginyl endoproteinase, has a pivotal role in excision and cyclization from cyclotide precursors. [ABSTRACT FROM AUTHOR]

• Premise of the study: Microsatellite markers were developed using second-generation sequencing in Solanum rostratum as a tool to study the reproductive biology and genetic structure of this invasive species. • Methods and Results: Thirteen microsatellites were successfully discovered and amplified in a single multiplexed PCR. All loci showed genetic variation in S. rostratum . Cross-amplification in five closely related taxa was successful for a subset of loci. • Conclusions: The set of 13 microsatellite markers developed here provides a time-effective and cost-effective genetic tool to study the reproductive biology of S. rostratum . The demonstrated transferability of the PCR multiplex to related taxa also highlights its usefulness for evolutionary studies across Solanum sect. Androceras. [ABSTRACT FROM AUTHOR]

• Premise of the study: An anatomical examination of dry and fleshy fruits within the Solanaceae was carried out to identify comparable stages throughout development as well as features exclusive to each type of fruit. We studied fruit development of Nicotiana and Petunia, which have the plesiomorphic capsular fruit; Solanum and Iochroma, characterized by a derived fleshy berry; Cestrum , an independent origin of a fleshy fruit; and Datura , a reversion to a dry fruit. • Methods: Pre- and postanthesis carpels and fruits of all species were collected, sectioned, stained, and examined using light microscopy. • Key results: Comparable stages of carpel and fruit development were identified in all species. Furthermore, anatomical and developmental features were identified that characterize capsules in Solanaceae, including lack of increase in the number of pericarp cell layers, formation of a sclerified endocarp, and elongation of the epidermal cells of the placenta. Pericarps of fleshy fruits of the Solanoideae are characterized by abundant collenchyma, an increase in the number of cell layers, and a parenchymatous endocarp often expanding into the locules. Anatomical data show that early developmental stages of the fruit of Cestrum, a berry, are similar to the capsular fruits of Petunia and Nicotiana; similarly, Datura, one of the few capsular members of the Solanoideae, shares several anatomical features with closely related berried taxa. • Conclusions: Ontogenetically, all fleshy or all dry fruits do not necessarily share a common developmental ground plan. Independent evolution of fleshiness, sclerification, dryness, and dehiscence are discussed in a phylogenetic context. [ABSTRACT FROM AUTHOR]

In eukaryotic organisms, horizontal gene transfer (HGT) is regarded as an important though infrequent source of reticulate evolution. Many confirmed instances of natural HGT involving multicellular eukaryotes come from flowering plants. This review intends to provide a synthesis of present knowledge regarding HGT in higher plants, with an emphasis on tobacco and other species in the Solanaceae family because there are numerous detailed reports concerning natural HGT events, involving various donors, in this family. Moreover, in-depth experimental studies using transgenic tobacco are of great importance for understanding this process. Valuable insights are offered concerning the mechanisms of HGT, the adaptive role and regulation of natural transgenes, and new routes for gene trafficking. With an increasing amount of data on HGT, a synthetic view is beginning to emerge. [ABSTRACT FROM AUTHOR]

* Premise of the study: Solanum section Herpystichum is a lineage that comprises both widespread and very narrowly distributed species. This study investigates the phylogenetic relationships of sect. Herpystichum and evaluates several phylogenetic methods for analysis of multiple sequences. * Methods: Sequence data from seven nuclear (ITS, GBSSI, and five COSII) and three plastid (psbA-- trnH, trnT -- trnF, and trnS -- trnG) regions were concatenated and analyzed under maximum parsimony and Bayesian criteria. In addition, we used two analytical methods that take into account differences in topologies resulting from the analyses of the individual markers: Bayesian Estimation of Species Trees (BEST) and supertree analysis. * Key results: The monophyletic Solanum sect. Herpystichum was resolved with moderate support in the concatenated maximum parsimony and Bayesian analyses and the supertree analysis, and relationships within the section were well-resolved and strongly supported. The BEST topology, however, was poorly resolved. Also, because of how BEST deals with missing sequences, > 25% of our accessions, including two species, had to be excluded from the analyses. Our results indicate a progenitordescendent relationship with two species nested within the widespread S. evolvulifolium. * Conclusions: Analytical methods that consider individual topologies are important for studies based on multiple molecular markers. On the basis of analyses in this study, BEST had the serious shortcoming that taxa with missing sequences must be removed from the analysis or they can produce spurious topologies. Supertree analysis provided a good alternative for our data by allowing the inclusion of all 10 species of sect. Herpystichum. [ABSTRACT FROM AUTHOR]

• Premise of the study: Understanding the demographic history of natural populations in relation to the geographic features in their habitats is an important step toward deciphering the mechanisms of evolutionary processes in nature. This study investigates how the complex geographic and ecological features of the Andes play a role in demographic history, species divergence, dispersal patterns, and hybridization in wild tomato species. • Methods: We investigated spatial genetics of two closely related wild tomato species, Solanum lycopersicum and S. pimpinel-lifolium, by integrating amplified fragment length polymorphism (AFLP) marker data and geographic information system (GIS)-derived geographic and climatic data. • Key results: The two species represent genetically distinct lineages largely separated by the Andes, but hybridize extensively in central to northern Ecuador, likely mediated by the transitional climatic conditions between those of the two species. Solanum lycospericum has likely experienced a severe population bottleneck during the colonization of the eastern Andes followed by a rapid population expansion. • Conclusions: The study demonstrates that the evolutionary patterns of the two wild tomatoes, including demographic history, dispersal patterns, interspecific divergence, and hybridization, are intimately related to the complex geographic and ecological features of the Andes. Integrating genetic data across the genome and GIS-derived environmental data can provide insights into the patterns of complex evolutionary processes in nature. [ABSTRACT FROM AUTHOR]

• Premise of the study: The taxonomy of cultivated potatoes has been highly controversial, with estimates of species numbers ranging from 3 to 17. Ploidy level has been one of the most important taxonomic characters to recognize cultivated potato species, containing diploid (2n = 2x = 24), triploid (2n = 3x = 36), tetraploid (2n = 4x = 48), and pentaploid (2n = 5x = 60) cultivars. We tested the environmental associations of different ploidy levels in cultivated potato species that traditionally have been recognized as Linnaean taxa to see whether, in combination with prior morphological, molecular, and crossing data, some of the ploidy variants can be recognized as distinct taxa. • Methods: We summarize 2780 chromosome counts of landrace cultivated potatoes, provide georeferences 2048 of them, and analyze these data for 20 environmental variables at 10-min resolution using the randomForest algorithm to explore associations with taxa and ploidy variants. • Key results: Except for the S. tuberosum Chilotanum Group and extreme northern and southern range extensions of the Andigenum Group, it is impossible to find distinct habitats for the ploidy variants of the S. tuberosum Andigenum Group. • Conclusions: Our distributional and ecological data, in combination with prior results from morphology, microsatellites, and crossing data, provide yet additional data to support a major reclassification of cultivated potato species. A rational, stable, and universally accepted taxonomy of this major crop plant will greatly aid all users of wild and cultivated potatoes from breeders to gene bank managers to ecologists and evolutionary biologists. [ABSTRACT FROM AUTHOR]

• Premise of the study: Some floral traits could be selected by pollinators and nonpollinator agents, and studying the floral traits shaped by physical agents could reveal adaptive mechanisms to the environment. We explored the adaptive significance of the change in floral orientation, from pendulous flowers to erect fruits that have a persistent calyx, in Anisodus luridus, a perennial native to the Qinghai-Tibet Plateau (QTP). • Methods: We examined the effect of flower orientation on pollinator visitation rates, pollen deposition efficiency, pollen quantity, and pollen viability to estimate whether pendulous flowers have improved male fitness. We then measured seed production and seed germination rate to assess whether erect fruits have enhanced female fitness. • Key results: Pendulous flowers did not have any preferred pollinators or increased pollen deposition. In artificially erected flowers, the number of pollen grains greatly decreased after rainwash. Pollen germination experiments indicated that pollen damage by water and exposure to solar radiation is serious. In the persistent calyx that holds water within it, the temperature inside the calyx changed slower than in the calyx that had the water removed. After supplemental pollination, the seed number, seed set, and seed mass of fruits that had water removed from the calyx were reduced greatly in both years. • Conclusions: We conclude that the change in floral orientation could enhance male and female fitness of A. luridus and is effectively adaptive to the alpine environments, indicating a strong selection by the combined pressure from various abiotic nonpollinator agents in shaping the floral traits of this alpine plant. [ABSTRACT FROM AUTHOR]

• Premise of the study: Embryonic inbreeding depression is a key influence on mating system evolution and can be difficult to estimate in self-incompatible species. A pollen chase experiment was used to estimate the magnitude of embryonic inbreeding depression in Costa Rican Witheringia solanacea, a species polymorphic for self-incompatibility (SI). In a pollen chase experiment, bud self-pollinations are followed after anthesis by outcross pollinations, with a comparable pair of outcross pollinations used as a control. Lowered seed set for the self-precedence treatment indicates embryonic inbreeding depression. • Methods: Embryonic inbreeding depression was assayed for self-compatible (SC) individuals and for SI plants from two populations that differ quantitatively in the onset and enzymatic activity of their SI response. Microsatellite markers were used to assay the selfing rate of a sample of surviving progeny from the prior self-pollination treatment. • Key results: SC individuals showed no evidence of embryonic inbreeding depression. In SI plants, prior self-pollination reduced seed number by 28-70%, depending on population. Microsatellite genotyping revealed that embryonic inbreeding depression was even more severe than estimated by the phenotypic data: for mature fruits resulting from self-pollination precedence, the majority of the progeny were the result of outcross fertilization. • Conclusions: Lineage-specific purging of recessive lethals has accompanied the evolution of SC in this species. SI populations show contrasting levels of embryonic inbreeding depression, with nearly complete embryonic lethality upon selfing in the Monteverde population. In the face of high embryonic inbreeding depression, an increase in selfing rate can evidently occur only under severe pollen limitation. [ABSTRACT FROM AUTHOR]

Understanding the role of geography and ecology in species divergence is central to the study of evolutionary diversification. We used climatic, geographic, and biological data from nine wild Andean tomato species to describe each species' ecological niche and to evaluate the likely ecological and geographical modes of speciation in this clade. Using data from >1000 wild accessions and publicly available data derived from geographic information systems for various environmental variables, we found most species pairs were significantly differentiated for one or more environmental variables. By comparing species' predicted niches generated by species distribution modeling (SDM), we found significant niche differentiation among three of four sister-species pairs, suggesting ecological divergence is consistently associated with recent divergence. In comparison, based on age-range correlation (ARC) analysis, there was no evidence for a predominant geographical (allopatric vs. sympatric) context for speciation in this group. Overall, our results suggest an important role for environmentally mediated differentiation, rather than simply geographical isolation, in species divergence. [ABSTRACT FROM AUTHOR]

The co-occurrence of elaborate flowers visited by specific groups of pollinators and capacity for autonomous selfing in the same plant species has puzzled evolutionary biologists since the time of Charles Darwin. To examine whether autonomous selfing and floral specialization evolved in association, we quantified the autofertility level (AFI) in nine Schizanthus species characterized by a wide range of pollination specialization, revealing AFI values of 0.02 to complete selfing. An independent contrasts analysis conducted on AFIs and number of functional pollinator groups showed that autonomous selfing evolved from an ancestral out-crossing system as plants became increasingly specialized (r = -0.82). To assess whether autonomous selfing together with specialization acts as a reproductive assurance mechanism, we estimated spatial and interannual variation in fruit set due to pollinator failure in two closely related high Andean Schizanthus species differing in their specialization levels. Variation in pollinator failure rate was more pronounced and autonomous selfing increased fruit production over biotically assisted pollination in the more specialized species. Our study suggests that specialized pollination deems species more vulnerable to pollinator fluctuation thus promoting the evolution of delayed autonomous selfing. [ABSTRACT FROM AUTHOR]