Androgen deprivation is the cornerstone of prostate cancer treatment. It results in involution of the normal gland to ~90% of its original size because of the loss of luminal cells. The prostate regenerates when androgen is restored, a process postulated to involve stem cells. Using single-cell RNA sequencing, we identified a rare luminal population in the mouse prostate that expresses stemlike genes (Sca1+ and Psca+) and a large population of differentiated cells (Nkx3.1+, Pbsn+). In organoids and in mice, both populations contribute equally to prostate regeneration, partly through androgen-driven expression of growth factors (Nrg2, Rspo3) by mesenchymal cells acting in a paracrine fashion on luminal cells. Analysis of human prostate tissue revealed similar differentiated and stemlike luminal subpopulations that likewise acquire enhanced regenerative potential after androgen ablation. We propose that prostate regeneration is driven by nearly all persisting luminal cells, not just by rare stem cells.

Although drought is recognized as an important limitation to wheat (Triticum aestivum L.) production in many regions, drought resistance selection techniques are not adequately developed. In 1984–1985 and 1985–1986, field experiments were conducted in Stillwater, OK, to determine potential drought resistance parameters and their inheritance in winter wheat. Single plants of drought resistant ‘TAM W‐101’ and drought susceptible ‘Sturdy’, their F1 and F2 progeny, and backcrosses of the F1 to each parent were evaluated under a rain shelter. Tiller number was recorded throughout the growing season. As stress developed during reproductive development, water potential (WP), solute potential (SP), turgor potential (TP), relative water content (RWC) were measured at 7‐ to 10‐d intervals on single leaves until tlag leaf senescence. Tiller number and growth rate were similar among the six populations. Water potential, WP components, and RWC declined with increasing drought stress, but no significant differences among populations were found, in WP, SP, or TP. Relative water content differed significantly among populations under increasing drought stress. TAM W‐101 maintained a higher RWC under drought conditions than Sturdy, and had a longer grain‐filling period. Comparison of the RWC values among populations indicated that differences were controlled predominantly by genes with additive effects. Narrow‐sense heritability (h2) of RWC increased as drought stress intensified and reached a maximum value of 0.64 1 wk prior to flag leaf senescence. With this high h2, RWC shows promise as a selection criterion for drought resistance in winter wheat.

BackgroundSingle nucleotide polymorphisms (SNPs) are ideally suited for the construction of high-resolution genetic maps, studying population evolutionary history and performing genome-wide association mapping experiments. Here, we used a genome-wide set of 1536 SNPs to study linkage disequilibrium (LD) and population structure in a panel of 478 spring and winter wheat cultivars (Triticum aestivum) from 17 populations across the United States and Mexico.ResultsMost of the wheat oligo pool assay (OPA) SNPs that were polymorphic within the complete set of 478 cultivars were also polymorphic in all subpopulations. Higher levels of genetic differentiation were observed among wheat lines within populations than among populations. A total of nine genetically distinct clusters were identified, suggesting that some of the pre-defined populations shared significant proportion of genetic ancestry. Estimates of population structure (FST) at individual loci showed a high level of heterogeneity across the genome. In addition, seven genomic regions with elevated FST were detected between the spring and winter wheat populations. Some of these regions overlapped with previously mapped flowering time QTL. Across all populations, the highest extent of significant LD was observed in the wheat D-genome, followed by lower LD in the A- and B-genomes. The differences in the extent of LD among populations and genomes were mostly driven by differences in long-range LD ( > 10 cM).ConclusionsGenome- and population-specific patterns of genetic differentiation and LD were discovered in the populations of wheat cultivars from different geographic regions. Our study demonstrated that the estimates of population structure between spring and winter wheat lines can identify genomic regions harboring candidate genes involved in the regulation of growth habit. Variation in LD suggests that breeding and selection had a different impact on each wheat genome both within and among populations. The higher extent of LD in the wheat D-genome versus the A- and B-genomes likely reflects the episodes of recent introgression and population bottleneck accompanying the origin of hexaploid wheat. The assessment of LD and population structure in this assembled panel of diverse lines provides critical information for the development of genetic resources for genome-wide association mapping of agronomically important traits in wheat.

Grain yield and associated agronomic traits are important factors in wheat (Triticum aestivum L.) improvement. Knowledge regarding the number, genomic location, and effect of quantitative trait loci (QTL) would facilitate marker-assisted selection and the development of cultivars with desirable characteristics. Our objectives were to identify QTLs directly and indirectly affecting grain yield expression. A population of 132 F12 recombinant inbred lines (RILs) was derived by single-seed descent from a cross between the Chinese facultative wheat Ning7840 and the US soft red winter wheat Clark. Phenotypic data were collected for 15 yield and other agronomic traits in the RILs and parental lines from three locations in Oklahoma from 2001 to 2003. Twenty-nine linkage groups, consisting of 363 AFLP and 47 SSR markers, were identified. Using composite interval mapping (CIM) analysis, 10, 16, 30, and 14 QTLs were detected for yield, yield components, plant adaptation (shattering and lodging resistance, heading date, and plant height), and spike morphology traits, respectively. The QTL effects ranged from 7 to 23%. Marker alleles from Clark were associated with a positive effect for the majority of QTLs for yield and yield components, but gene dispersion was the rule rather than the exception for this RIL population. Often, QTLs were detected in proximal positions for different traits. Consistent, co-localized QTLs were identified in linkage groups 1AL, 1B, 4B, 5A, 6A, and 7A, and less consistent but unique QTLs were identified on 2BL, 2BS, 2DL, and 6B. Results of this study provide a benchmark for future efforts on QTL identification for yield traits.

Wheat (Triticum aestivum L.) grain mineral concentrations tend to decrease as yields increase, therefore, breeding for yield improvement may reduce wheat nutritional quality. The objectives of this study were to survey grain mineral concentration in Great Plains hard winter wheat to assess (i) the heritable variation for grain mineral concentrations in the germplasm pool, (ii) the effects of more than 50 yr of wheat breeding on mineral concentrations, and (iii) opportunities to exploit the underlying physiological relationship between grain protein concentration (GPC) and grain mineral concentration to improve nutritional quality. Grain mineral concentrations were measured in a panel of 299 winter wheat genotypes grown in 2012 and 2013 in Oklahoma and Nebraska. Cadmium and Li concentrations were most heritable across environments, and the low heritabilities of Fe and Zn concentrations will challenge direct breeding efforts, particularly within low‐yield environments that minimize genetic variance. Within the subset of cultivars released from 1960 to 2014, grain yield increased 0.58 to 1.25% yr−1, and Zn concentration decreased 0.15 to 0.26% yr−1, relative to the reference cultivar Scout 66. Grain concentrations of Fe, P, and S also trended lower over this time period. Significant genetic variation persists within contemporary germplasm. Among 93 cultivars released since 2000, Zn concentration max/min ratios ranged from 1.5 to 2.3, depending on environment. The positive interrelationship between GPC and grain Fe and Zn concentrations could be exploited in a yield‐neutral breeding strategy that selects genotypes based on positive grain protein deviation (GPD) in multiple environments.