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Premise of the studyProject Baseline is a seed bank that offers an unprecedented opportunity to examine spatial and temporal dimensions of microevolution during an era of rapid environmental change. Over the upcoming 50 years, biologists will withdraw genetically representative samples of past populations from this time capsule of seeds and grow them contemporaneously with modern samples to detect any phenotypic and molecular evolution that has occurred during the intervening time.MethodsWe carefully developed this living genome bank using protocols to enhance its experimental value by collecting from multiple populations and species across a broad geographical range in sites that are likely to be preserved into the future. Seeds are accessioned with site and population data and are stored by maternal line under conditions that maximize seed longevity. This open-access resource will be available to researchers at regular intervals to evaluate contemporary evolution.Key resultsTo date, the Project Baseline collection includes 100-200 maternal lines of each of 61 species collected from over 831 populations on sites that are likely to be preserved into the future across the United States (∼78,000 maternal lines). Our strategically designed collection circumvents some problems that can cloud the results of "resurrection" studies involving naturally preserved or existing seed collections that are available fortuitously.ConclusionsThe resurrection approach can be coupled with long-established and newer techniques over the next five decades to elucidate genetic change and thereby vastly improve our understanding of temporal and spatial changes in phenotype and the evolutionary processes underlying it.

Understanding the genetic basis of natural phenotypic variation is of great importance, particularly since selection can act on this variation to cause evolution. We examined expression and allelic variation in candidate flowering time loci in Brassica rapa plants derived from a natural population and showing a broad range in the timing of first flowering. The loci of interest were orthologs of the Arabidopsis genes FLC and SOC1 (BrFLC and BrSOC1, respectively), which in Arabidopsis play a central role in the flowering time regulatory network, with FLC repressing and SOC1 promoting flowering. In B. rapa, there are four copies of FLC and three of SOC1. Plants were grown in controlled conditions in the lab. Comparisons were made between plants that flowered the earliest and latest, with the difference in average flowering time between these groups ∼30 days. As expected, we found that total expression of BrSOC1 paralogs was significantly greater in early than in late flowering plants. Paralog-specific primers showed that expression was greater in early flowering plants in the BrSOC1 paralogs Br004928, Br00393 and Br009324, although the difference was not significant in Br009324. Thus expression of at least 2 of the 3 BrSOC1 orthologs is consistent with their predicted role in flowering time in this natural population. Sequences of the promoter regions of the BrSOC1 orthologs were variable, but there was no association between allelic variation at these loci and flowering time variation. For the BrFLC orthologs, expression varied over time, but did not differ between the early and late flowering plants. The coding regions, promoter regions and introns of these genes were generally invariant. Thus the BrFLC orthologs do not appear to influence flowering time in this population. Overall, the results suggest that even for a trait like flowering time that is controlled by a very well described genetic regulatory network, understanding the underlying genetic basis of natural variation in such a quantitative trait is challenging.

The maintenance of outcrossing in cleistogamous plants that produce both open, facultatively outcrossing chasmogamous (CH), and closed, obligate selfing cleistogamous (CL) flowers is puzzling because CL reproduction is thought to be more reliable and less costly. A possible explanation for the maintenance of CH flowers is the avoidance of inbreeding depression. However, inbreeding depression for cleistogamous species has rarely been quantified. In this study, we estimate levels of inbreeding depression in plants from three populations of Triodanis perfoliata (L.) Nieuwl., a dimorphic cleistogamous annual, under greenhouse conditions. Estimates of inbreeding depression at multiple life stages in all three populations were low and often not different from zero. Inbreeding depression at specific life stages varied, with two populations showing later-acting inbreeding depression, which is also found in other selfing species. In two of the study populations, selfed CL progeny outperformed selfed CH progeny, indicating a flower-type effect. The low levels of inbreeding depression and the superior fitness of CL compared with selfed CH flowers that weobserved make the maintenanceof CH flowersin this system surprising, and suggest that other advantages of outcrossing CH flowers are likely responsible for maintaining mixed mating in this species. Key words: breeding system, Campanulaceae, cleistogamy, inbreeding depression, mixed mating system, plasticity, reproductive ecology. Resume : Le maintien du croisement eloigne chez les vegetaux cleistogames qui produit tant des fleurs ouvertes, a croisement eloigne chasmogame (CH) facultatif que des fleurs fermees, a autofecondation cleistogame (CL) obligee, est intrigant car la reproduction CL est presumee plus fiable et moins couteuse. Une explication possible pour le maintien de fleurs CH consiste en l'evitement de la depression endogamique. Toutefois, la depression endogamique des especes cleistogames a rarement ete quantifiee. Dans cette etude, les auteurs ont estime les niveaux de depression endogamique chez les plants de trois populations de Triodanis perfoliata (L.) Nieuwl., une plante annuelle dimorphique cleistogame, en conditions de serre. Les estimes de la depression endogamique a differents stades de vie chez les trois populations etaient faibles et souvent non differents de zero. La depression endogamique a un stade de vie specifique variait, avec deux populations montrant une depression endogamique plus tardive, qui etait aussi trouvee chez d'autres especes endogames. Chez deux des populations etudiees, la descendance CL issue de l'autofecondation etait plus performante que la descendance CH issue de l'autofecondation, indiquant un effet du type de fleur. Les faibles niveaux de depression endogamique et la valeur d'adaptation superieure des fleurs CL comparativement aux fleurs CH issues de l'autofecondation, comme observes par les auteurs, rendent le maintien des fleurs CH dans ce systeme surprenant, et suggerent que d'autres avantages du croisement eloigne des fleurs CH sont probablement responsables du maintien du croisement mixte chez cette espece. [Traduit par la Redaction] Mots-cles : systeme de croisement, Campanulaceae, cleistogamie, depression endogamique, systeme de croisement mixte, plasticite, ecologie de la reproduction., Introduction Plant reproductive systems are remarkably diverse, but the major selective pressures affecting the evolution of plant mating strategies can be distilled into a few key ecological and genetic factors. [...]

Flowering phenology, or the timing of plant reproduction, is a key component of plant fitness, influencing plant survival, reproduction, and the presence (or absence) of temporal reproductive barriers between closely related species. Flowering phenology often varies across space, and advancing spring phenology is a common response to anthropogenic climate change. Characterizing phenological variation at higher taxonomic levels can reveal whether related species vary in their sensitivity to climate change. We characterized flowering phenology across space and through time in the dimorphic cleistogamous genus Triodanis using vetted digital herbarium and iNaturalist records of Triodanis species spanning 153 years across the contiguous United States. We found considerable overlap in peak flowering time in all seven Triodanis species, suggesting that factors other than flowering time, such as self-fertilization, may contribute to the maintenance of species barriers in this genus. Geography influenced the peak-flowering date in four species, but the direction and strength of these relationships varied between species, perhaps reflecting local variation in abiotic conditions and species-level differences in flowering cues. We found phenological advancement over the past century in four of seven Triodanis species, suggesting that this genus is potentially tracking climate change through flowering time shifts. [ABSTRACT FROM AUTHOR]

Premise of research. The assumption of a trade-off between growth and defense is a major tenet of plant defense theory, though not all prior research has supported this trade-off. If this trade-off exists, plant genotypes that grow rapidly should be less well defended against herbivory than more slowly growing genotypes. Furthermore, selection for rapid growth and early flowering should indirectly result in plants becoming more susceptible to herbivory.Methodology. We tested this hypothesis by examining the effects of artificial selection for rapid cycling (fast growth and early flowering) in Brassica rapa on preference and performance of a specialist (Pieris rapae) and a generalist (Trichoplusia ni) lepidopteran herbivore. We used the resurrection approach, comparing ancestral (before selection) and descendant (after selection) B. rapa plants, which allowed us to directly examine evolutionary responses of traits affecting herbivory. We employed choice and no-choice feeding trials and oviposition trials to assess herbivore preference and performance on ancestral and descendant leaf tissue.Pivotal results. There was no difference in feeding preference of the specialist for ancestral or descendant leaf tissue. The specialist and generalist caterpillars showed greater weight gain on ancestral compared to descendant leaf tissue, but specialist caterpillars consumed more descendant than ancestral leaf tissue. Specialist butterflies showed an oviposition preference for ancestors. There was no difference in trichome counts or specific leaf area, but descendants had lower leaf carbon∶nitrogen ratios than ancestors.Conclusions. These results suggest that artificial selection for rapid cycling caused evolutionary changes in plant traits that influenced herbivore defense, indicating an important indirect effect of selection. However, the responses did not match predictions based on the idea of a trade-off between growth and defense, which challenges a fundamental assumption of plant defense theory. [ABSTRACT FROM AUTHOR]

The inheritance of style-morphs was investigated in tetraploid populations of tristylous O xalis alpina ( Oxalidaceae) to determine if alleles controlling style-morphs are expressed at duplicated loci. In tetraploid populations, a dominant S allele leads to expression of the short-styled phenotype at the short/non-short locus and is epistatic to the M allele at the mid/long locus. The M allele results in expression of the mid-styled phenotype but only if the S allele is absent. Long-styled morphs are homozygous recessive at the short and mid loci. Test crosses of many tetraploid short-styled individuals resulted in segregations of short-, mid- and long-styled individuals which, because of linkage between the short and mid loci, can only occur with polyploidy and expression of alleles at duplicated loci. Segregation patterns from three crosses suggest the possibility of disomic inheritance via preferential pairing of chromosomes in tetraploid populations of O . alpina. Segregation patterns in the progeny of mid-styled individuals indicated that only a few individuals had more than one copy of the M allele, despite the potential for accumulation of M alleles via self-fertilization of partially self-compatible mid-styled morphs in some populations. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 179, 308-318. [ABSTRACT FROM AUTHOR]

As climate change progresses, we are observing widespread changes in phenotypes in many plant populations. Whether these phenotypic changes are directly caused by climate change, and whether they result from phenotypic plasticity or evolution, are active areas of investigation. Here, we review terrestrial plant studies addressing these questions. Plastic and evolutionary responses to climate change are clearly occurring. Of the 38 studies that met our criteria for inclusion, all found plastic or evolutionary responses, with 26 studies showing both. These responses, however, may be insufficient to keep pace with climate change, as indicated by eight of 12 studies that examined this directly. There is also mixed evidence for whether evolutionary responses are adaptive, and whether they are directly caused by contemporary climatic changes. We discuss factors that will likely influence the extent of plastic and evolutionary responses, including patterns of environmental changes, species' life history characteristics including generation time and breeding system, and degree and direction of gene flow. Future studies with standardized methodologies, especially those that use direct approaches assessing responses to climate change over time, and sharing of data through public databases, will facilitate better predictions of the capacity for plant populations to respond to rapid climate change. [ABSTRACT FROM AUTHOR]

Plant breeding systems can vary widely among populations, yet few studies have investigated abiotic factors contributing to variation across a broad geographic range. Here we investigate variation in reproductive traits of Triodanis perfoliata (Campanulaceae), a species that exhibits dimorphic cleistogamy, a condition in which individual plants have both closed (selfing: cleistogamous: CL) and open (selfing or outcrossing: chasmogamous: CH) flowers. Chasmogamous production is theorized to be more costly because CH flowers have a larger exposed surface area and thus are more likely to lose more water than CL flowers. We examine relationships between abiotic conditions (temperature, precipitation and soil characteristics) and variation in breeding systems across 14 widespread populations using ordinary least squares models. We found that a large proportion of breeding system variation was described by climate and soil variables (R 2 = 0.65–0.92). These results support the hypothesis that variation in the environment drives variation in breeding system allocation. Our broad geographic analyses provide a framework for mechanistic studies of cleistogamy, and employ a novel approach for examining reproductive traits and environmental variation at large scales. Given that two major components of our models were temperature and precipitation, our study further emphasizes the potential for ongoing climate change to alter plant breeding systems. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the impact of a pilot intervention for physicians to support their treatment of patients at risk for opioid abuse., Setting, Design and Patients, Participants: Patients at risk for opioid abuse enrolled in Medicare plans were identified from July 1, 2012 to April 30, 2014 (N = 2,391), based on a published predictive model, and linked to 4,353 opioid-prescribing physicians. Patient-physician clusters were randomly assigned to one of four interventions using factorial design., Interventions: Physicians received one of the following: Arm 1, patient information; Arm 2, links to educational materials for diagnosis and management of pain; Arm 3, both patient information and links to educational materials; or Arm 4, no communication., Main Outcome Measures: Difference-in-difference analyses compared opioid and pain prescriptions, chronic high-dose opioid use, uncoordinated opioid use, and opioid-related emergency department (ED) visits. Logistic regression compared diagnosis of opioid abuse between cases and controls postindex., Results: Mailings had no significant impact on numbers of opioid or pain medications filled, chronic high-dose opioid use, uncoordinated opioid use, ED visits, or rate of diagnosed opioid abuse. Relative to Arm 4, odds ratios (95% CI) for diagnosed opioid abuse were Arm 1, 0.95(0.63-1.42); Arm 2, 0.83(0.55-1.27); Arm 3, 0.72(0.46-1.13). While 84.7 percent had ≥1 psychiatric diagnoses during preindex (p = 0.89 between arms), only 9.5 percent had ≥1 visit with mental health specialists (p = 0.53 between arms)., Conclusions: Although this intervention did not affect pain-related outcomes, future interventions involving care coordination across primary care and mental health may impact opioid abuse and improve quality of life of patients with pain.

Understanding the genetic basis of natural phenotypic variation is of great importance, particularly since selection can act on this variation to cause evolution. We examined expression and allelic variation in candidate flowering time loci in Brassica rapa plants derived from a natural population and showing a broad range in the timing of first flowering. The loci of interest were orthologs of the Arabidopsis genes FLC and SOC1 (BrFLC and BrSOC1, respectively), which in Arabidopsis play a central role in the flowering time regulatory network, with FLC repressing and SOC1 promoting flowering. In B. rapa, there are four copies of FLC and three of SOC1. Plants were grown in controlled conditions in the lab. Comparisons were made between plants that flowered the earliest and latest, with the difference in average flowering time between these groups ∼30 days. As expected, we found that total expression of BrSOC1 paralogs was significantly greater in early than in late flowering plants. Paralog-specific primers showed that expression was greater in early flowering plants in the BrSOC1 paralogs Br004928, Br00393 and Br009324, although the difference was not significant in Br009324. Thus expression of at least 2 of the 3 BrSOC1 orthologs is consistent with their predicted role in flowering time in this natural population. Sequences of the promoter regions of the BrSOC1 orthologs were variable, but there was no association between allelic variation at these loci and flowering time variation. For the BrFLC orthologs, expression varied over time, but did not differ between the early and late flowering plants. The coding regions, promoter regions and introns of these genes were generally invariant. Thus the BrFLC orthologs do not appear to influence flowering time in this population. Overall, the results suggest that even for a trait like flowering time that is controlled by a very well described genetic regulatory network, understanding the underlying genetic basis of natural variation in such a quantitative trait is challenging.