Description: Background: The identification of the loci and specific alleles underlying variation in quantitative traits is an important goal for evolutionary biologists and breeders. Despite major advancements in genomics technology, moving from QTL to causal alleles remains a major challenge in genetics research. Near-isogenic lines are the ideal raw material for QTL validation, refinement of QTL location and, ultimately, gene discovery. Results: In this study, a population of 75 Arabidopsis thaliana near-isogenic lines was developed from an existing recombinant inbred line (RIL) population derived from a cross between physiologically divergent accessions Kas-1 and Tsu-1. First, a novel algorithm was developed to utilize genome-wide marker data in selecting RILs fully isogenic to Kas-1 for a single chromosome. Seven such RILs were used in 2 generations of crossing to Tsu-1 to create BC1 seed. BC1 plants were genotyped with SSR markers so that lines could be selected that carried Kas-1 introgressions, resulting in a population carrying chromosomal introgressions spanning the genome. BC1 lines were genotyped with 48 genome-wide SSRs to identify lines with a targeted Kas-1 introgression and the fewest genomic introgressions elsewhere. 75 such lines were selected and genotyped at an additional 41 SNP loci and another 930 tags using 2b-RAD genotyping by sequencing. The final population carried an average of 1.35 homozygous and 2.49 heterozygous introgressions per line with average introgression sizes of 5.32 and 5.16 Mb, respectively. In a simple case study, we demonstrate the advantage of maintaining heterozygotes in our library whereby fine-mapping efforts are conducted simply by self-pollination. Crossovers in the heterozygous interval during this single selfing generation break the introgression into smaller, homozygous fragments (sub-NILs). Additionally, we utilize a homozygous NIL for validation of a QTL underlying stomatal conductance, a low heritability trait. Conclusions: The present results introduce a new and valuable resource to the Brassicaceae research community that enables rapid fine-mapping of candidate loci in parallel with QTL validation. These attributes along with dense marker coverage and genome-wide chromosomal introgressions make this population an ideal starting point for discovery of genes underlying important complex traits of agricultural and ecological significance.

Description: Background: Solely in Europoe, Salmonella Typhimurium causes more than 100,000 infections per year.Improved detection of livestock colonised with S. Typhimurium is necessary to preventfoodborne diseases. Currently, commercially available ELISA assays are based on a mixtureof O-antigens (LPS) or total cell lysate of Salmonella and are hampered by cross-reaction.The identification of novel immunogenic proteins would be useful to develop ELISA baseddiagnostic assays with a higher specificity. Results: A phage display library of the entire Salmonella Typhimurium genome was constructed and47 immunogenic oligopeptides were identified using a pool of convalescent sera from pigsinfected with Salmonella Typhimurium. The corresponding complete genes of seven of theidentified oligopeptids were cloned. Five of them were produced in E. coli. The immunogeniccharacter of these antigens was validated with sera from pigs infeced with S. Tyhimurium andcontrol sera from non-infected animals. Finally, human antibody fragments (scFv) againstthese five antigens were selected using antibody phage display and characterised. Conclusion: In this work, we identified novel immunogenic proteins of Salmonella Typhimurium andgenerated antibody fragments against these antigens completely based on phage display. Fiveimmunogenic proteins were validated using a panel of positive and negative sera forprospective applications in diagnostics of Salmonela Typhimurium.