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At least 19 recordsLinked to original sources
PubMed2025

Synthetic allopolyploidy unveils hybridization-driven transcriptional reprogramming underlying thermal adaptation in Cucumis.

Both heterosis (hybrid vigor) resulting from hybridization and genetic plasticity conferred by whole-genome duplication (WGD) are recognized as drivers of evolutionary success and ecological adaptation in plants. Allopolyploids, which combine both hybridization and WGD, are widespread in both natural and agricultural settings and often exhibit superior performance. However, the relative contributions of these two elements to the success of allopolyploids remain poorly understood. Here, we employed an experimentally reconstructed allotetraploid Cucumis species (C. × hytivus, 2n = 4x = 38) and its diploid interspecific hybrid progenitor (allodiploid, 2n = 2x = 19) to decouple and investigate the distinct and combined contributions of hybridization and whole-genome doubling to immediate genetic and phenotypic consequences of allopolyploid formation under environmental stress. Both C. × hytivus and the allodiploid exhibited superior heat tolerance compared with the parental species with significantly higher semi-lethal temperature and enhanced physiological acclimation capacity. While the allodiploid and allotetraploid retain transcriptomic features where differences persist (e.g., WGCNA modules), comparative analysis of the 15,680 homoeologous gene pairs in the allodiploid and allotetraploid under heat stress (45°C) versus control conditions (28°C) revealed conserved heat-responsive transcriptional plasticity, suggesting that enhanced thermotolerance in C. × hytivus is presented as consequences arising dominantly after interspecific hybridization. This study provides mechanistic insights into allopolyploid adaptation through experimental reconstruction of allopolyploid genomes, demonstrating that hybridization initiates key transcriptional and physiological advantages under stress, subsequent WGD stabilizes these adaptations and contributes to the full phenotypic realization. This work decouples the roles of interspecific hybridization and WGD and proposes a synthetic biology approach for developing climate-resilient crops.

Hybridization, Genetic↗
PubMed2025

Beyond parental lines: multi-omics analyses reveal epigenetic and transcriptional mechanisms underlying heterosis in Oryza sativa × Oryza rufipogon hybrids.

Heterosis, or hybrid vigor, refers to the superior phenotypes of a hybrid compared with their parents and is widely exploited in agriculture. Interspecific hybrids within the Oryza genus demonstrate significant potential for the systematic improvement of rice varieties. Nevertheless, the mechanistic basis underlying heterosis in interspecific Oryza hybrids remains poorly understood. Here, we systematically performed phenotypic characterization, whole-genome bisulfite sequencing, RNA sequencing, and small RNA profiling using Oryza sativa L. ssp. japonica cv. Nipponbare (NIP), Oryza rufipogon Griff. acc. CWR, and their resulting F1 hybrid (named as NC). NIP and CWR showed distinct phenotypic and molecular differences. The interspecific hybrid, NC, exhibited significant yield heterosis. In the hybrid, most epigenetic and transcriptional features displayed additive inheritance patterns relative to parental lines. Analysis revealed that domestication-selected genes maintained relatively low DNA methylation coupled with high expression levels in both hybrid and parental lines. Additionally, we identified that non-additive miRNAs were potentially involved in regulating fertility, cell growth, and cell division processes in the hybrid. A significant negative correlation was observed between DNA methylation level and gene expression. Functional enrichment analysis revealed that hybrid-MPV DEGs were significantly associated with flowering time regulation, carbohydrate metabolism, photosynthesis, protein phosphorylation, seed development, and defense responses. Through weighted gene co-expression network analysis, we identified 102 functional gene modules, six of which were significantly associated with yield-related heterosis. Collectively, our results provide a multi-omics framework for understanding interspecific hybridization between elite cultivars and wild rice relatives, highlighting CWR as an untapped genetic reservoir for rice improvement.

Oryza↗
PubMed1979

A case of behavioral heterosis in mice: quantitative and qualitative aspects of performance in a water-escape task.

Fourteen hundred and four mice from two inbred strains (Balb/c and C57BL/6), F1, F2, and backcrosses were subjected to four trials in a water-escape task and to a swimming test. Detailed analysis of mice behavior in these situations showed that the "F1 hybrid vigor" affected behavioral characters not directly related to physical vigor but of potential adaptive value. Their superiority was mainly due to more frequent adoption of an efficient behavioral tactic (direct or edge escape paths toward the exit) and more rapid progress with experience in this respect than other generations exhibited. These results clearly show that heterosis is not limited to physical vigor but may extend to behavioral and even psychological characters.

Animals↗
PubMed2026

Dissecting genetic variance structure and evaluating genomic prediction models for single-cross hybrids derived from Stiff Stalk and Non-Stiff Stalk maize heterotic groups.

The early 20th-century discovery of heterosis and the establishment of heterotic groups transformed maize (Zea mays L.) into a keystone of global agriculture. However, maize breeding faces two significant challenges: the gradual decline of general combining ability (GCA) variance within heterotic groups and the impracticality of testing all possible single crosses in the early stages of a breeding program. Here, we developed genomic best linear unbiased prediction (GBLUP)-based multikernel models, using additive and two alternative nonadditive genomic relationship matrices, to estimate the variance components associated with the general combining ability of Stiff Stalk (SS) and Non-Stiff Stalk (NSS) heterotic groups and the specific combining ability arising from their crosses. We further applied these models to predict the performance of untested single-cross combinations under varying levels of parental information. We showed that the SS and NSS groups retained significant GCA variance across traits in both early- and late-maturity groups. The SS group, in contrast, exhibited no detectable GCA variance in grain yield for the intermediate-flowering subset of hybrids, highlighting a limitation for future genetic improvement. Furthermore, our results showed that GBLUP-based multikernel models effectively identified superior hybrids when parental information was available. In the absence of this information, however, these models underperformed compared to covariance-based approaches. Both nonadditive matrices yielded similar results, indicating that they capture comparable genetic relationship patterns despite their distinct formulations. Overall, this study sheds light on the future use of US maize commercial germplasm and demonstrates how GBLUP-based multikernel models can improve the efficiency of hybrid breeding programs.

Zea mays↗
PubMed2025

Filamentous cheater phages drive bacterial and phage populations to lower fitness.

Many bacteria carry phage genome(s) in their chromosome, which intertwines the fitness of the bacterium and the phage. Most Pseudomonas aeruginosa strains carry filamentous phages called Pf that establish chronic infections and do not require host lysis to spread. However, spontaneous mutations in the Pf repressor gene (pf5r) can allow extreme phage production that slows bacterial growth and increases cell death, violating an apparent détente between bacterium and phage. We observed this paradoxical outcome in an evolution experiment with P. aeruginosa in media simulating nutrients from the cystic fibrosis airway. Bacteria containing pf5r mutant phage grow to a lower density but directly outcompete their ancestor and convert them into pf5r mutants via phage superinfection. Reduced fitness therefore spreads throughout the bacterial population, driven by weaponized Pf. Yet high intracellular phage replication facilitates another evolutionary conflict: "cheater miniphages" lacking capsid genes and the superinfection exclusion gene (pfsE) invade populations of full-length phages within cells. Although bacteria containing both full-length phages and miniphages are most immune to superinfection by limiting the Pf receptor, this hybrid vigor is extremely unstable, as a classic Tragedy of the Commons scenario ensues that causes complete prophage loss. The entire cycle - from phage hyperactivation to miniphage invasion to prophage loss - can occur within 24h, showcasing rapid coevolution between bacteria and their filamentous phages. This study demonstrates that P. aeruginosa, and potentially many other bacterial species that carry filamentous prophages, risk being exploited by these phages in a runaway process that reduces fitness of both host and virus.

Inoviridae↗
PubMed1979

[Phenomenon of parental resistance and its genetic regulation].

Lymphocytes of mice F1 (CBA X M523) and F1 (A X M523) transplanted to 1000 R irradiated CBA or A mice responded to the test antigens--SRBC or S. typhi Vi-antigen--by formation of 100--1000 times less antibody forming cells than in syngeneic recipients. An intermediate result is achieved when the lymphoid cells are transplanted to the irradiated M523 mice. Lymphocytes of mice F1 (A X CBA), F1 (CBA X C57Bl/6), or F1 (A X A.CA) developed a similar immune response in the irradiated syngeneic mice and in both parental lines. The ability of parental line M523 to respond to SRBC was the same as in the other lines studied when examined in situ or in adoptive transfer experiments. The stem hemopoietic cells of mice F1 (CBA X M523) develop in the spleen of CBA mice 2--2.5 times less hemopoietic colonies than in the spleen of syngeneic animals. A conclusion was drawn that mutation M523 in CBA mice inhibited the proliferation and differentiation of hemopoietic and lymphoid cells in the irradiated nonsyngeneic recipients.

Animals↗
PubMedDate not supplied

[Characteristics of heterogeneity of serum albumin in heterosis-hybrid chickens].

A comparative study was performed for isoelectric and electrophoretic spectra blood serum albumin of parental breeds of chickens and their heterosis hybrids --broiler cocks. The method of isoelectric focusing within the surcrose density gradient and pH 4-6 created by the gradient of sucrose, mannitol and boron-borate buffer (pH 8.5) concentrations was applied. The electrophoretic spectrum of the serum albumin fraction homogeneous in the agar gel was obtained by electrophoresis in 7% polyacrylamide gel. The isoelectric spectrum of heterosis hybrid albumin is established to be more heterogeneous and during isoelectric focusing it is divided within a range of pH 4.6-5.2 into seven fractions against four-five components of the parent breed albumin. Among them it is possible to distinguish the fraction involving more than 50% of the total protein (the great component) and some small components with different protein content and belonging wither to a more acid or more basic region as compared to pI of the great component. The pI value of the great component for hybrid albumin is shifted towards the acid region (4.76 against 4.85 and 5.07 in albumin of the parent breeds). Small component of hybrid albumin are characterized by an increase in their amount, but pI of the fraction is within the range of values peculiar to albumin of the maternal and paternal lines. The albumin preparations of all the studied chicken breeds isolated from blood serum by electrophoresis in the agar gel manifest multiplicity of the protein bands in a 7% polyacrylamide gel. The electric spectra of hybrid albumin and parent breeds albumin differ in the distribution pattern of the components and their quantitative composition. A relative electrophoretic mobility of the intensively stained dense band which represents the main electrophoretic component is increased in hydrid albumin with the respect to albumin of the maternal line but is identical to the paternal line.

Animals↗
PubMed1978

[Contibution of the X chromosme to the increased resistance of inbred Drosophila melanogaster hybrids to physical effects].

Effects of high sub-lethal temperature and UV-irradiation on surviving of inbred lines of Drosophila melanogaster and its F1 hybrids derived from reciprocal crosses between these lines are investigated. High resistance of F1 hybrids to these factors was observed as compared with that of parental inbred lines. D. melanogaster females in inbred lines and F1 hybrids were more resistant than males. Differences in the resistance between females and males were more pronounced in hybrids.

Animals↗
PubMed1979

[Effect of antimacrophage serum on the graft vs. host reaction in F1 hybrid mice].

The author carried out experiments on 100 one-week old F1 hybrids (BALB-C C57-BL) and succeeded to obtain moderately manifested CvH reaction, injecting them with peritoneal macrophages from one of the parent's lines-BALB-C, immunized preliminary with lymphocytes from other parentalline. Preliminary incubation of macrophages with AMC without participation of compliment did not affect significantly the manifestations of GvH reaction, while successive incubation of macrophages with AMC and compliment inhibited completely the ability of the cells to induce GvH reaction. This effect was in correlation with the vitality of the cells.

Animals↗
PubMed2024

QTL mapping for seed vigor-related traits under artificial aging in common wheat in two introgression line (IL) populations.

BACKGROUND: Seed vigor recognized as a quantitative trait is of particular importance for agricultural production. However, limited knowledge is available for understanding genetic basis of wheat seed vigor. METHODS: The aim of this study was to identify quantitative trait loci (QTL) responsible for 10 seed vigor-related traits representing multiple aspects of seed-vigor dynamics during artificial aging with 6 different treatment times (0, 24, 36, 48, 60, and 72 h) under controlled conditions (48 °C, 95% humidity, and dark). The mapping populations were two wheat introgression lines (IL-1 and IL-2) derived from recipient parent (Lumai 14) and donor parent (Shaanhan 8675 or Jing 411). RESULTS: A total of 26 additive QTLs and 72 pairs of epistatic QTLs were detected for wheat seed-vigor traits. Importantly, chromosomes 1B and 7B contained several co-located QTLs, and chromosome 2A had a QTL-rich region near the marker Xwmc667, indicating that these QTLs may affect wheat seed vigor with pleiotropic effects. Furthermore, several possible consistent QTLs (hot-spot regions) were examined by comparison analysis of QTLs detected in this study and reported previously. Finally, a set of candidate genes for wheat seed vigor were predicted to be involved in transcription regulation, carbohydrate and lipid metabolism. CONCLUSION: The present findings lay new insights into the mechanism underlying wheat seed vigor, providing valuable information for wheat genetic improvement especially marker-assisted breeding to increase seed vigor and consequently achieve high grain yield despite of further investigation required.

Triticum↗
PubMed2026

The Spatiotemporal Genetic Architecture of Seed Vigor in Upland Cotton.

Seed vigor underpins uniform crop establishment, but its dynamic genetics are understudied. Combining high-resolution temporal phenotyping and genomics in upland cotton, we used the SeedRanger platform to record 17 image-based traits every 30 min over 120 h, revealing stage-specific heritability and identifying 541 seed-vigor loci. These loci show extensive pleiotropy and temporal coordination, forming a genetic network that preserves developmental continuity; 8.9% overlap regions under domestication selection, indicating concurrent optimization with fiber yield. Functional validation of FLA2, a candidate gene underlying a dynamic QTL, implicates auxin-mediated control of radicle elongation and cotyledon development. This temporal framework exposes dynamic genetic architecture and breeding targets for high-vigor crops.

Gossypium↗
PubMed2026

Alternatively spliced killer-protector system confers S19-mediated hybrid male sterility in rice.

Hybrid sterility limits the use of strong interspecific heterosis and S19 is a major locus that confers hybrid sterility between Oryza sativa (Asian cultivated rice) and Oryza glaberrima (African cultivated rice). However, the S19 is not yet cloned and its underlying mechanism remains elusive. In this study, we identify two closely linked genes (S19A1 and S19A7) specific to African rice allele that encode a killer-protector module at the S19 locus. Two alternatively spliced transcripts expressed from the killer gene S19A1 (S19A1.1 and S19A1.2) encode mitochondria-targeted cytotoxic proteins that cause toxicity diversity for somatic and/or gametic cell death, respectively. However, S19A7 interacts with S19A1.1 and S19A1.2, blocking their cytotoxic effect. Because the Asian rice S19 allele lacks S19A1 and S19A7, male gametes that carry this allele are selectively aborted in Asian-African F1 hybrids. Knockout of S19A1 can overcome S19-mediated hybrid sterility. Haplotype analysis reveals that the functional S19 allele is absent in non-AA-genome Oryza species and likely emerged in the O. barthii-O. glaberrima lineage through a multi-step evolutionary process. Our findings provide insight into the genetic mechanisms responsible for hybrid sterility between Asian and African rice and suggest genetic and biotechnological strategies for the use of interspecific heterosis in rice.

Oryza↗
PubMed1979

Genetic variation in prenatal survival and litter size.

The nature of genetic variation in litter size and its components was examined using results of long term selection and of crossing selected lines of mice. Selection for small and for large litters produced strains with mean litter size of approximately 6 and 15, respectively. The large litter size line showed a period of renewed response after 45 generations of selection, following a period of 15 generations with no response. The relative contribution of genotype of the dam and of the embryo to prenatal survival was examined using results of selection, crossing and embryo transfer. Genotype of female carrying the litter was responsible for most of the observed differences. Genes for poor survival expressed by the embryo were present in some strains, but accounted for less variation than did maternal genotype. Information from the selected lines and from crosses among them provided evidence for dominance of genes affecting fertility and prenatal survival and additivity of genes affecting ovulation rate and body weight. The information was used to suggest a model for more effective exploitation of heterosis using breeds or strains of animals of known performance for different components. The extent of genetic variation for prenatal survival suggests that natural selection in this species may not always be for maximum survival. It is suggested that the ability to reduce litter size after conception, in response to nutritional or other stress, may at times be of selective advantage, contributing to maintenance of genetic variation in survival rate.

Animals↗