Explore the vast range of titles available.

Background Peanut ( Arachis hypogaea L.) is a vital global crop, frequently threatened by both abiotic and biotic stresses. Among the most damaging biotic stresses is Tomato spotted wilt virus (TSWV), which causes peanut spotted wilt disease resulting in significant yield loss. Developing TSWV-resistant cultivars is crucial to new cultivar release. Previous studies have used a subset of the “S” recombinant inbred line (RIL) population derived from SunOleic 97R and NC94022 and identified quantitative trait loci (QTLs) for resistance to TSWV. These studies utilized different genotyping techniques and found large consistent genomic regions on chromosome A01. The objective of this study was to fine map the QTL and identify candidate genes using the entire population of 352 RILs and high-density, high-quality peanut SNP arrays. Results We used both versions of the peanut SNP arrays with five years of disease ratings, and successfully mapped the long-sought peanut spotted wilt disease resistance locus, PSWDR-1 . QTL analyses identified two major QTLs, explaining 41.43% and 43.69% of the phenotypic variance within 3.6 cM and 0.28 cM intervals using the peanut Axiom_ Arachis -v1 and Axiom_ Arachis -v2 SNP arrays, respectively, on chromosome A01. These QTLs corresponded to 295 kb and 235 kb physical intervals. The unique overlap region of these two QTLs was 488 kb. A comparison of the genetic linkage map with the reference genome revealed a 1.3 Mb recombination “cold spot” (11.325–12.646 Mb) with only two recombination events of RIL-S1 and RIL-S17, which displayed contrasting phenotypes. Sequencing of these two recombinants confirmed the cold spot with only five SNPs detected within this region. Conclusions This study successfully identified a peanut spotted wilt disease resistance locus, PSWDR-1 , on chromosome A01 within a recombination “cold spot”. The PSWDR-1 locus contains three candidate genes, a TIR-NBS-LRR gene ( Arahy.1PK53M ), a glutamate receptor-like gene ( Arahy.RI1BYW ), and an MLO-like protein ( Arahy.FX71XI ). These findings provide a foundation for future functional studies to validate the roles of these candidate genes in resistance and application in breeding TSWV-resistant peanut cultivars.

By combining 7077 SNPs and 61 microsatellites, we present the first linkage map for some of the early diverged lineages of the common frog, Rana temporaria, and the densest linkage map to date for this species. We found high homology with the published linkage maps of the Eastern and Western lineages but with differences in the order of some markers. Homology was also strong with the genome of the Tibetan frog Nanorana parkeri and we found high synteny with the clawed frog Xenopus tropicalis. We confirmed marked heterochiasmy between sexes and detected nonrecombining regions in several groups of the male linkage map. Contrary to the expectations set by the male heterogamety of the common frog, we did not find male heterozygosity excess in the chromosome previously shown to be linked to sex determination. Finally, we found blocks of loci showing strong transmission ratio distortion. These distorted genomic regions might be related to genetic incompatibilities between the parental populations, and are promising candidates for further investigation into the genetic basis of speciation and adaptation in the common frog.

Numerous studies have argued that environmental variations may contribute to evolution through the generation of novel heritable variations via meiotic recombination, which plays a crucial role in crop domestication and improvement. Rice is one of the most important staple crops, but no direct estimate of recombination events has yet been made at a fine scale. Here, we address this limitation by sequencing 41 rice individuals with high sequencing coverage and c. 900 000 accurate markers. An average of 33.9 crossover (c. 4.53 cM Mb⁻¹) and 2.47 non‐crossover events were detected per F₂plant, which is similar to the values in Arabidopsis. Although not all samples in the stress treatment group showed an increased number of crossover events, environmental stress increased the recombination rate in c. 28.5% of samples. Interestingly, the crossovers showed a highly uneven distribution among and along chromosomes, with c. 13.9% of the entire genome devoid of crossovers, including 11 of the 12 centromere regions, and c. 0.72% of the genome containing large numbers of crossovers (> 50 cM Mb⁻¹). The gene ontology (GO) categories showed that genes clustered within the recombination hot spot regions primarily tended to be involved in responses to environmental stimuli, suggesting that recombination plays an important role for adaptive evolution in rapidly changing environments.

Multiple species within the basidiomycete genus Cryptococcus cause cryptococcal disease. These species are estimated to affect nearly a quarter of a million people leading to ∼180,000 mortalities, annually. Sexual reproduction, which can occur between haploid yeasts of the same or opposite mating type, is a potentially important contributor to pathogenesis as recombination can generate novel genotypes and transgressive phenotypes. However, our quantitative understanding of recombination in this clinically important yeast is limited. Here, we describe genome-wide estimates of recombination rates in Cryptococcus deneoformans and compare recombination between progeny from α–α unisexual and a–α bisexual crosses. We find that offspring from bisexual crosses have modestly higher average rates of recombination than those derived from unisexual crosses. Recombination hot and cold spots across the C. deneoformans genome are also identified and are associated with increased GC content. Finally, we observed regions genome-wide with allele frequencies deviating from the expected parental ratio. These findings and observations advance our quantitative understanding of the genetic events that occur during sexual reproduction in C. deneoformans, and the impact that different forms of sexual reproduction are likely to have on genetic diversity in this important fungal pathogen.

Background Cold stress significantly challenges cotton growth and productivity, yet the genetic and molecular mechanisms underlying cold tolerance remain poorly understood. Results We employed RNA-seq and iterative weighted gene co-expression network analysis (WGCNA) to investigate gene and transposable element (TE) expression changes at six cold stress time points (0 h, 2 h, 4 h, 6 h, 12 h, 24 h). Thousands of differentially expressed genes (DEGs) were identified, exhibiting time-specific patterns that highlight a phase-dependent transcriptional response. While the A and D subgenomes contributed comparably to DEG numbers, numerous homeologous gene pairs showed differential expression, indicating regulatory divergence. Iterative WGCNA uncovered 125 gene co-expression modules, with some enriched in specific chromosomes or chromosomal regions, suggesting localized regulatory hotspots for cold stress response. Notably, transcription factors, including MYB73, ERF017, MYB30, and OBP1, emerged as central regulators within these modules. Analysis of 11 plant hormone-related genes revealed dynamic expression, with ethylene (ETH) and cytokinins (CK) playing significant roles in stress-responsive pathways. Furthermore, we documented over 15,000 expressed TEs, with differentially expressed TEs forming five distinct clusters. TE families, such as LTR/Copia, demonstrated significant enrichment in these expression clusters, suggesting their potential role as modulators of gene expression under cold stress. Conclusions These findings provide valuable insights into the complex regulatory networks underlying cold stress response in cotton, highlighting key molecular components involved in cold stress regulation. This study provides potential genetic targets for breeding strategies aimed at enhancing cold tolerance in cotton.

Although meiosis in warm-blooded organisms takes place in a narrow temperature range, meiosis in many organisms occurs over a wide variety of temperatures. We analyzed the properties of meiosis in the yeast Saccharomyces cerevisiae in cells sporulated at 14°C, 30°C, or 37°C. Using comparative-genomic-hybridization microarrays, we examined the distribution of Spo11-generated meiosis-specific double-stranded DNA breaks throughout the genome. Although there were between 300 and 400 regions of the genome with high levels of recombination (hot spots) observed at each temperature, only about 20% of these hot spots were found to have occurred independently of the temperature. In S. cerevisiae , regions near the telomeres and centromeres tend to have low levels of meiotic recombination. This tendency was observed in cells sporulated at 14°C and 30°C, but not at 37°C. Thus, the temperature of sporulation in yeast affects some global property of chromosome structure relevant to meiotic recombination. Using single-nucleotide polymorphism (SNP)-specific whole-genome microarrays, we also examined crossovers and their associated gene conversion events as well as gene conversion events that were unassociated with crossovers in all four spores of tetrads obtained by sporulation of diploids at 14°C, 30°C, or 37°C. Although tetrads from cells sporulated at 30°C had slightly (20%) more crossovers than those derived from cells sporulated at the other two temperatures, spore viability was good at all three temperatures. Thus, despite temperature-induced variation in the genetic maps, yeast cells produce viable haploid products at a wide variety of sporulation temperatures. IMPORTANCE In the yeast Saccharomyces cerevisiae , recombination is usually studied in cells that undergo meiosis at 25°C or 30°C. In a genome-wide analysis, we showed that the locations of genomic regions with high and low levels of meiotic recombination (hot spots and cold spots, respectively) differed dramatically in cells sporulated at 14°C, 30°C, and 37°C. Thus, in yeast, and likely in other non-warm-blooded organisms, genetic maps are strongly affected by the environment. In the yeast Saccharomyces cerevisiae , recombination is usually studied in cells that undergo meiosis at 25°C or 30°C. In a genome-wide analysis, we showed that the locations of genomic regions with high and low levels of meiotic recombination (hot spots and cold spots, respectively) differed dramatically in cells sporulated at 14°C, 30°C, and 37°C. Thus, in yeast, and likely in other non-warm-blooded organisms, genetic maps are strongly affected by the environment.

During meiosis, combinatorial associations of genetic traits arise from homologous recombination between parental chromosomes. Histone H3 lysine 4 trimethylation marks meiotic recombination hotspots in yeast and mammals, but how this ubiquitous chromatin modification relates to the initiation of double-strand breaks (DSBs) dependent on Spo11 remains unknown. Here, we show that the tethering of a PHD-containing protein, Spp1 (a component of the COMPASS complex), to recombinationally cold regions is sufficient to induce DSB formation. Furthermore, we found that Spp1 physically interacts with Mer2, a key protein of the differentiated chromosomal axis required for DSB formation. Thus, by interacting with H3K4me3 and Mer2, Spp1 promotes recruitment of potential meiotic DSB sites to the chromosomal axis, allowing Spo11 cleavage at nearby nucleosome-depleted regions.

Background Protein–protein interactions (PPIs) are conveyed through binding interfaces or surface patches on proteins that become buried upon binding. Structural and biophysical analysis of many protein–protein interfaces revealed certain unique features of these surfaces that determine the energetics of interactions and play a critical role in protein evolution. One of the significant aspects of binding interfaces is the presence of binding hot spots, where mutations are highly deleterious for binding. Conversely, binding cold spots are positions occupied by suboptimal amino acids and several mutations in such positions could lead to affinity enhancement. While there are many software programs for identification of hot spot positions, there is currently a lack of software for cold spot detection. Results In this paper, we present Cold Spot SCANNER, a Colab Notebook, which scans a PPI binding interface and identifies cold spots resulting from cavities, unfavorable charge-charge, and unfavorable charge-hydrophobic interactions. The software offers a Py3DMOL-based interface that allows users to visualize cold spots in the context of the protein structure and generates a zip file containing the results for easy download. Conclusions Cold spot identification is of great importance to protein engineering studies and provides a useful insight into protein evolution. Cold Spot SCANNER is open to all users without login requirements and can be accessible at: https://colab.research.google.com/github/sagagugit/Cold-Spot-Scanner/blob/main/Cold_Spot_Scanner.ipynb .

Pigeon circovirus (PiCV) infects pigeon populations worldwide and has been associated with immunosuppression in younger pigeons. Recombination is a common mechanism of evolution that has previously been shown in various members of the Circoviridae family, including PiCV. In this study, three groups of pigeons acquired from separate lofts were screened for PiCV, and their genome sequence was determined. Following this, they were housed in a single loft for 22 days, during which blood and cloacal swab samples were taken. From these blood and cloacal swabs, PiCV genomes were determined with the aim to study the spread and recombination dynamics of PiCV in the birds. Genome sequences of PiCV were determined from seven pigeons (seven tested PiCV positive) before they were housed together in a loft (n = 58 sequences) and thereafter from the ten pigeons from blood and cloacal swabs (n = 120). These 178 PiCV genome sequences represent seven genotypes (98% pairwise identity genotype demarcation), and they share >88% genome-wide pairwise identity. Recombination analysis revealed 13 recombination events, and a recombination hotspot spanning the 3′ prime region, the replication-associated protein (rep) gene and the intergenic region. A cold spot in the capsid protein-coding region of the genome was also identified. The majority of the recombinant regions were identified in the rep coding region. This study provides insights into the evolutionary dynamics of PiCV in pigeons kept under closed rearing systems.

Enhancements in reproductive cold tolerance of sorghum are essential to expand growing areas into both high-latitude temperate areas and tropical high-altitude environments. Here we present first insights into the genetic architecture of this trait via genome-wide association studies in a broad genetic diversity set ( n = 330) phenotyped in multi-location field trials including high-altitude tropical (Mexico) and high-latitude temperate (Germany) environments. We observed a high degree of phenotypic variation and identified several novel, temperate-adapted accessions with superior and environmentally stable cold tolerance. Good heritability indicates strong potential for implementation of reproductive cold tolerance in breeding. Although the trait was found to be strongly quantitative, promising genomic regions with multiple-trait associations were found, including hotspots on chromosomes 3 and 10 which contain candidate genes implicated in different developmental and survival processes under abiotic stress conditions.