Whole genome resequencing of 51 Populus nigra (L.) individuals from across Western Europe was performed using Illumina platforms. A total number of 1 878 727 SNPs distributed along the P. nigra reference sequence were identified. The SNP calling accuracy was validated with Sanger sequencing. SNPs were selected within 14 previously identified QTL regions, 2916 expressional candidate genes related to rust resistance, wood properties, water-use efficiency and bud phenology and 1732 genes randomly spread across the genome. Over 10 000 SNPs were selected for the construction of a 12k Infinium Bead-Chip array dedicated to association mapping. The SNP genotyping assay was performed with 888 P. nigra individuals. The genotyping success rate was 91%. Our high success rate was due to the discovery panel design and the stringent parameters applied for SNP calling and selection. In the same set of P. nigra genotypes, linkage disequilibrium throughout the genome decayed on average within 5-7 kb to half of its maximum value. As an application test, ADMIXTURE analysis was performed with a selection of 600 SNPs spread throughout the genome and 706 individuals collected along 12 river basins. The admixture pattern was consistent with genetic diversity revealed by neutral markers and the geographical distribution of the populations. These newly developed SNP resources and genotyping array provide a valuable tool for population genetic studies and identification of QTLs through natural-population based genetic association studies in P. nigra.

Watercress (Rorippa nasturtium-aquaticum), wild rocket (Diplotaxis tenuifolia), and spinach (Spinacia oleracea) are commercial crops reported to have high concentrations of antioxidants, possibly contributing to disease prevention following human consumption. Following analysis of supermarket-purchased salad leaves, we report the antioxidant content potential of these species using two comparable techniques assessing the consistency between the assays – by the ferric reducing antioxidant power (FRAP) assay and the oxygen radical absorbance capacity (ORAC) assay. The leaves were harvested from both conventionally and organically managed crops, to investigate whether organic agriculture results in improved crop quality. Watercress had the highest FRAP and ability to scavenge free radicals, followed by spinach and rocket. For watercress and rocket, there was no significant effect of organic agriculture on FRAP and ORAC, but for spinach, the antioxidant potential was reduced and this was significant at the 5% level of probability for FRAP but not ORAC, although the trend was clear in both tests. We conclude that there is variation in salad crop antioxidant potential and that FRAP and ORAC are useful techniques for measuring antioxidants in these salad crops with similar ranking for each salad crop studied.

BackgroundSecond generation (2G) bioenergy from lignocellulosic feedstocks has the potential to develop as a sustainable source of renewable energy; however, significant hurdles still remain for large-scale commercialisation. Populus is considered as a promising 2G feedstock and understanding the genetic basis of biomass yield and feedstock quality are a research priority in this model tree species.ResultsWe report the first coppiced biomass study for 714 members of a wide population of European black poplar (Populus nigra L.), a native European tree, selected from 20 river populations ranging in latitude and longitude between 40.5 and 52.1°N and 1.0 and 16.4°E, respectively. When grown at a single site in southern UK, significant Site of Origin (SO) effects were seen for 14 of the 15 directly measured or derived traits including biomass yield, leaf area and stomatal index. There was significant correlation (p < 0.001) between biomass yield traits over 3 years of harvest which identified leaf size and cell production as strong predictors of biomass yield. A 12 K Illumina genotyping array (constructed from 10,331 SNPs in 14 QTL regions and 4648 genes) highlighted significant population genetic structure with pairwise FST showing strong differentiation (p < 0.001) between the Spanish and Italian subpopulations. Robust associations reaching genome-wide significance are reported for main stem height and cell number per leaf; two traits tightly linked to biomass yield. These genotyping and phenotypic data were also used to show the presence of significant isolation by distance (IBD) and isolation by adaption (IBA) within this population.ConclusionsThe three associations identified reaching genome-wide significance at p < 0.05 include a transcription factor; a putative stress response gene and a gene of unknown function. None of them have been previously linked to bioenergy yield; were shown to be differentially expressed in a panel of three selected genotypes from the collection and represent exciting, novel candidates for further study in a bioenergy tree native to Europe and Euro-Asia. A further 26 markers (22 genes) were found to reach putative significance and are also of interest for biomass yield, leaf area, epidermal cell expansion and stomatal patterning. This research on European P. nigra provides an important foundation for the development of commercial native trees for bioenergy and for advanced, molecular breeding in these species.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-016-0603-1) contains supplementary material, which is available to authorized users.

BackgroundConsuming watercress is thought to provide health benefits as a consequence of its phytonutrient composition. However, for watercress there are currently limited genetic resources underpinning breeding efforts for either yield or phytonutritional traits. In this paper, we use RNASeq data from twelve watercress accessions to characterize the transcriptome, perform candidate gene mining and conduct differential expression analysis for two key phytonutritional traits: antioxidant (AO) capacity and glucosinolate (GLS) content.ResultsThe watercress transcriptome was assembled to 80,800 transcripts (48,732 unigenes); 71 % of which were annotated based on orthology to Arabidopsis. Differential expression analysis comparing watercress accessions with ‘high’ and ‘low’ AO and GLS resulted in 145 and 94 differentially expressed loci for AO capacity and GLS respectively. Differentially expressed loci between high and low AO watercress were significantly enriched for genes involved in plant defence and response to stimuli, in line with the observation that AO are involved in plant stress-response. Differential expression between the high and low GLS watercress identified links to GLS regulation and also novel transcripts warranting further investigation. Additionally, we successfully identified watercress orthologs for Arabidopsis phenylpropanoid, GLS and shikimate biosynthesis pathway genes, and compiled a catalogue of polymorphic markers for future applications.ConclusionsOur work describes the first transcriptome of watercress and establishes the foundation for further molecular study by providing valuable resources, including sequence data, annotated transcripts, candidate genes and markers.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-016-2704-4) contains supplementary material, which is available to authorized users.

Twenty undergraduate students from introductory psychology classes watched a videotape of a lesson in Esperanto, took an 8-item quiz on Esperanto, and were paired as tutors with 20 additional students for a videotaped lesson in Esperanto. Both the tutors and the tutees were given an Esperanto study guide. After the lesson, all of the students completed a 16-item quiz on Esperanto.The most common behavior of the tutors was reading information from the study guide, followed by elaborating and bringing in new information. The tutors frequently gave incorrect information. The most common behavior of the tutees was repeating words or sentences at the request of the tutor. Stepwise multiple regression analysis revealed that the only tutor behavior related to success on the Esperanto quiz was elaborating and bringing in new information. The only tutee behavior related to success was asking for clarification of information. Total tutorhutee quiz scores were positively related to the tutor's elaborating and bringing in new information and the tutee's asking what was important to remember and negatively related to the tutor's giving incorrect information and asking what the tutee did not understand.At a medium-sized private university with a successful athletic program, members of the basketball team were studied over a four-year period through interviews and various participatory activities with the team. In contrast to popular perceptions, most of the athletes, even STUDENTSthose with deficient academic skills, entered college with idealistic academic expectations. In other words, most felt that college was a worthwhile pursuit for academic reasons alone, not just basketball, and nearly one-half requested placement in a preprofessional major. By the end of the freshman year, however, these idealistic expectations had for the most part turned to cynicism and disappointment.Both athletic and social experiences were found to play important roles in this transition. Among the several athletic factors were the professionalization of college basketball, the resultant time commitment necessary for participation in major college athletics, and the intervention of the coach in the athletes' academic lives, which lent a false sense of security. In addition, basketball had a powerful impact on the social lives of the athletes: they were housed together with other athletes, a practice that, given their different socioeconomic backgrounds, served to widen the gulf between the athletes and the rest of the students. Soon, when faced with inferior academic performance, the athletes turned inward, seeking solace among themselves in an atmosphere that disparaged academic performance. Because the only positive reinforcement came from basketball, even more effort was expended in this direction at the expense of academics. (49 reGDepartment of Sociology, University of Tulsa. 0002-22GMTBerzonsky, Michael D. Diffusion Within Marcia's Identity-Status Paradlgm: Does It Foreshadow Academic Problems? Journal of Youth and Adolescence, 1985,14 (Dece...