Enrichment and Diversification of the Wheat Genome via Alien Introgression.

Wheat, including durum and common wheat, respectively, is an allopolyploid with two or three homoeologous subgenomes originating from diploid wild ancestral species. The wheat genome's polyploid origin consisting of just three diploid ancestors has constrained its genetic variation, which has bottlenecked improvement. However, wheat has a large number of relatives, including cultivated crop species (e.g., barley and rye), wild grass species, and ancestral species. Moreover, each ancestor and relative has many other related subspecies that have evolved to inhabit specific geographic areas. Cumulatively, they represent an invaluable source of genetic diversity and variation available to enrich and diversify the wheat genome. The ancestral species share one or more homologous genomes with wheat, which can be utilized in breeding efforts through typical meiotic homologous recombination. Additionally, genome introgressions of distant relatives can be moved into wheat using chromosome engineering-based approaches that feature induced meiotic homoeologous recombination. Recent advances in genomics have dramatically improved the efficacy and throughput of chromosome engineering for alien introgressions, which has served to boost the genetic potential of the wheat genome in breeding efforts. Here, we report research strategies and progress made using alien introgressions toward the enrichment and diversification of the wheat genome in the genomics era.

Discovery of Proline-Based p300/CBP Inhibitors Using DNA-Encoded Library Technology in Combination with High-Throughput Screening.

E1A binding protein (p300) and CREB binding protein (CBP) are two highly homologous and multidomain histone acetyltransferases. These two proteins are involved in many cellular processes by acting as coactivators of a large number of transcription factors. Dysregulation of p300/CBP has been found in a variety of cancers and other diseases, and inhibition has been shown to decrease Myc expression. Herein, we report the identification of a series of highly potent, proline-based small-molecule p300/CBP histone acetyltransferase (HAT) inhibitors using DNA-encoded library technology in combination with high-throughput screening. The strategy of reducing ChromlogD and fluorination of metabolic soft spots was explored to improve the pharmacokinetic properties of potent p300 inhibitors. Fluorination of both cyclobutyl and proline rings of 22 led to not only reduced clearance but also improved cMyc cellular potency.

Effects of foliar fungicide on yield, micronutrients, and cadmium in grains from historical and modern hard winter wheat genotypes.

Plant breeding and disease management practices have increased the grain yield of hard winter wheat (Triticum aestivum L.) adapted to the Great Plains of the United States during the last century. However, the effect of genetic gains for seed yield and the application of fungicide on the micronutrient and cadmium (Cd) concentration in wheat grains is still unclear. The objectives of this study were to evaluate the effects of fungicide application on the productivity and nutritional quality of wheat cultivars representing 80 years of plant breeding efforts. Field experiments were conducted over two crop years (2017 and 2018) with eighteen hard winter wheat genotypes released between 1933 and 2013 in the presence or absence of fungicide application. For each growing season, the treatments were arranged in a split-plot design with the fungicide levels (treated and untreated) as the whole plot treatments and the genotypes as split-plot treatments in triplicate. The effects on seed yield, grain protein concentration (GPC), micronutrients, phytic acid, and Cd in grains were measured. While the yield of wheat was found to increase at annualized rates of 26.5 and 13.0 kg ha-1 yr-1 in the presence and absence of fungicide (P < 0.001), respectively, GPC (-190 and -180 mg kg-1 yr-1, P < 0.001), Fe (-35.0 and -44.0 µg kg-1 yr-1, P < 0.05), and Zn (-68.0 and -57.0 µg kg-1 yr-1, P < 0.01) significantly decreased during the period studied. In contrast to the other mineral elements, grain Cd significantly increased over time (0.4 µg kg-1 yr-1, P < 0.01) in the absence of fungicide. The results from this study are of great concern, as many mineral elements essential for human nutrition have decreased over time while the toxic heavy metal, Cd, has increased, indicating modern wheats are becoming a better vector of dietary Cd.

Genome-Wide Association Analysis Pinpoints Additional Major Genomic Regions Conferring Resistance to Soybean Cyst Nematode (Heterodera glycines Ichinohe).

Soybean cyst nematode (Heterodera glycines Ichinohe) (SCN) is the most destructive pest affecting soybeans [Glycine max (L.) Merr.] in the U.S. To date, only two major SCN resistance alleles, rhg1 and Rhg4, identified in PI 88788 (rhg1) and Peking (rhg1/Rhg4), residing on chromosomes (Chr) 18 and 8, respectively, have been widely used to develop SCN resistant cultivars in the U.S. Thus, some SCN populations have evolved to overcome the PI 88788 and Peking derived resistance, making it a priority for breeders to identify new alleles and sources of SCN resistance. Toward that end, 461 soybean accessions from various origins were screened using a greenhouse SCN bioassay and genotyped with Illumina SoySNP50K iSelect BeadChips and three KASP SNP markers developed at the Rhg1 and Rhg4 loci to perform a genome-wide association study (GWAS) and a haplotype analysis at the Rhg1 and Rhg4 loci. In total, 35,820 SNPs were used for GWAS, which identified 12 SNPs at four genomic regions on Chrs 7, 8, 10, and 18 that were significantly associated with SCN resistance (P < 0.001). Of those, three SNPs were located at Rhg1 and Rhg4, and 24 predicted genes were found near the significant SNPs on Chrs 7 and 10. KASP SNP genotyping results of the 462 accessions at the Rhg1 and Rhg4 loci identified 30 that carried PI 88788-type resistance, 50 that carried Peking-type resistance, and 58 that carried neither the Peking-type nor the PI 88788-type resistance alleles, indicating they may possess novel SCN resistance alleles. By using two subsets of SNPs near the Rhg1 and Rhg4 loci obtained from SoySNP iSelect BeadChips, a haplotype analysis of 461 accessions grouped those 58 accessions differently from the accessions carrying Peking or PI 88788 derived resistance, thereby validating the genotyping results at Rhg1 and Rhg4. The significant SNPs, candidate genes, and newly characterized SCN resistant accessions will be beneficial for the development of DNA markers to be used for marker-assisted breeding and developing soybean cultivars carrying novel sources of SCN resistance.

Discovery of a crystalline sulforaphane analog with good solid-state stability and engagement of the Nrf2 pathway in vitro and in vivo.

The antioxidant natural product sulforaphane (SFN) is an oil with poor aqueous and thermal stability. Recent work with SFN has sought to optimize methods of formulation for oral and topical administration. Herein we report the design of new analogs of SFN with the goal of improving stability and drug-like properties. Lead compounds were selected based on potency in a cellular screen and physicochemical properties. Among these, 12 had good aqueous solubility, permeability and long-term solid-state stability at 23 °C. Compound 12 also displayed comparable or better efficacy in cellular assays relative to SFN and had in vivo activity in a mouse cigarette smoke challenge model of acute oxidative stress.

Analytical approaches for quantification of a Nrf2 pathway activator: overcoming bioanalytical challenges to support a toxicity study.

Activation of the Nrf2 stress pathway is known to play an important role in the defense mechanism against electrophilic and oxidative damage to biological macromolecules (DNA, lipids, and proteins). Chemical inducers of Nrf2 such as sulforaphane, dimethyl fumarate (Tecfidera®), CDDO-Me (bardoxolone-methyl), and 3-(dimethylamino)-4-((3-isothiocyanatopropyl)(methyl)amino)cyclobut-3-ene-1,2-dione (a synthetic sulforaphane analogue; will be referred to as ) have the ability to react with Keap1 cysteine residues, leading to activation of the Antioxidant Response Element (ARE). Due to their electrophilic nature and poor matrix stability, these compounds represent great challenges when developing bioanalytical methods to evaluate in vivo exposure. like SFN reacts rapidly with glutathione (GSH) and nucleophilic groups in proteins to form covalent adducts. In this work, three procedures were developed to estimate the exposure of in a non-GLP 7 day safety study in rats: (1) protein precipitation of blood samples with methanol containing the free thiol trapping reagent 4-fluoro-7-aminosulfonylbenzofurazan (ABD-F) to measure GSH- and N-acetylcysteine conjugated metabolites of ; (2) an Edman degradation procedure to cleave and analyze N-terminal adducts of at the valine moiety; and (3) treatment with ammonium hydroxide to measure circulating free- and all sulfhydryl bound .