Crossovers Research Articles

Regulation of interference-sensitive crossover distribution ensures crossover assurance in Arabidopsis

During meiosis, crossovers (COs) are typically required to ensure faithful chromosomal segregation. Despite the requirement for at least one CO between each pair of chromosomes, closely spaced double COs are usually underrepresented due to a phenomenon called CO interference. Like Mus musculus and Saccharomyces cerevisiae, Arabidopsis thaliana has both interference-sensitive (Class I) and interference-insensitive (Class II) COs. However, the underlying mechanism controlling CO distribution remains largely elusive. Both AtMUS81 and AtFANCD2 promote the formation of Class II CO. Using both AtHEI10 and AtMLH1 immunostaining, two markers of Class I COs, we show that AtFANCD2 but not AtMUS81 is required for normal Class I CO distribution among chromosomes. Depleting AtFANCD2 leads to a CO distribution pattern that is intermediate between that of wild-type and a Poisson distribution. Moreover, in Atfancm, Atfigl1, and Atrmi1 mutants where increased Class II CO frequency has been reported previously, we observe Class I CO distribution patterns that are strikingly similar to Atfancd2. Surprisingly, we found that AtFANCD2 plays opposite roles in regulating CO frequency in Atfancm compared with either in Atfigl1 or Atrmi1. Together, these results reveal that although AtFANCD2, AtFANCM, AtFIGL1, and AtRMI1 regulate Class II CO frequency by distinct mechanisms, they have similar roles in controlling the distribution of Class I COs among chromosomes.

An Induced Mutation in HvRECQL4 Increases the Overall Recombination and Restores Fertility in a Barley HvMLH3 Mutant Background.

Plant breeding relies on the meiotic recombination or crossing over to generate the new combinations of the alleles along and among the chromosomes. However, crossing over is constrained in the crops such as barley by a combination of the low frequency and biased distribution. In this study, we attempted to identify the genes that limit the recombination by performing a suppressor screen for the restoration of fertility to the semi-fertile barley mutant desynaptic10 (des10), carrying a mutation in the barley ortholog of MutL-Homolog 3 (HvMLH3), a member of the MutL-homolog (MLH) family of DNA mismatch repair genes. des10 mutants exhibit reduced recombination and fewer chiasmata, resulting in the loss of obligate crossovers (COs) leading to chromosome mis-segregation. We identified several candidate suppressor lines and confirmed their restored fertility in an Hvmlh3 background in the subsequent generations. We focus on one of the candidate suppressor lines, SuppLine2099, which showed the most complete restoration of fertility. We characterized this line by using a target-sequence enrichment and sequencing (TENSEQ) capture array representing barley orthologs of 46 meiotic genes. We found that SuppLine2099 contained a C/T change in the anti-CO gene RecQ-like helicase 4 (RECQL4) resulting in the substitution of a non-polar glycine to a polar aspartic acid (G700D) amino acid in the conserved helicase domain. Single nucleotide polymorphism (SNP) genotyping of F3 populations revealed a significant increase in the recombination frequency in lines with Hvrecql4 in the Hvmlh3 background that was associated with the restoration of fertility. The genotyping also indicated that there was nearly double the recombination levels in homozygous Hvrecql4 lines compared to the wild type (WT). However, we did not observe any significant change in the distribution of CO events. Our results confirm the anti-CO role of RECQL4 in a large genome cereal and establish the possibility of testing the utility of increasing recombination in the context of traditional crop improvement.

The E3 ubiquitin ligase DESYNAPSIS1 regulates synapsis and recombination in rice meiosis.

Synaptonemal complex (SC) assembly and homologous recombination, the most critical events during prophase I, are the prerequisite for faithful meiotic chromosome segregation. However, the underlying regulatory mechanism remains largely unknown. Here, we reveal that a functional RING finger E3 ubiquitin ligase, DESYNAPSIS1 (DSNP1), plays significant roles in SC assembly and homologous recombination during rice meiosis. In the dsnp1 mutant, homologous synapsis is discontinuous and aberrant SC-like polycomplexes occur independent of coaligned homologous chromosomes. Accompanying the decreased foci of HEI10, ZIP4, and MER3 on meiotic chromosomes, the number of crossovers (COs) decreases dramatically in dsnp1 meiocytes. Furthermore, the absence of central elements largely restores the localization of non-ZEP1 ZMM proteins and the number of COs in the dsnp1 background. Collectively, DSNP1 stabilizes the canonical tripartite SC structure along paired homologous chromosomes and further promotes the formation of COs.

Downregulation of Barley Regulator of Telomere Elongation Helicase 1 Alters the Distribution of Meiotic Crossovers.

Programmed meiotic DNA double-strand breaks (DSBs), necessary for proper chromosomal segregation and viable gamete formation, are repaired by homologous recombination (HR) as crossovers (COs) or non-crossovers (NCOs). The mechanisms regulating the number and distribution of COs are still poorly understood. The regulator of telomere elongation helicase 1 (RTEL1) DNA helicase was previously shown to enforce the number of meiotic COs in Caenorhabditis elegans but its function in plants has been studied only in the vegetative phase. Here, we characterised barley RTEL1 gene structure and expression using RNA-seq data previously obtained from vegetative and reproductive organs and tissues. Using RNAi, we downregulated RTEL1 expression specifically in reproductive tissues and analysed its impact on recombination using a barley 50k iSelect SNP Array. Unlike in C. elegans, in a population segregating for RTEL1 downregulated by RNAi, high resolution genome-wide genetic analysis revealed a significant increase of COs at distal chromosomal regions of barley without a change in their total number. Our data reveal the important role of RTEL1 helicase in plant meiosis and control of recombination.

Evolution of crossover interference enables stable autopolyploidy by ensuring pairwise partner connections in Arabidopsis arenosa

SummaryPolyploidy is a major driver of evolutionary change. Autopolyploids, which arise by within-species whole-genome duplication, carry multiple nearly identical copies of each chromosome. This presents an existential challenge to sexual reproduction. Meiotic chromosome segregation requires formation of DNA crossovers (COs) between two homologous chromosomes. How can this outcome be achieved when more than two essentially equivalent partners are available? We addressed this question by comparing diploid, neo-autotetraploid, and established autotetraploid Arabidopsis arenosa using new approaches for analysis of meiotic CO patterns in polyploids. We discover that crossover interference, the classical process responsible for patterning of COs in diploid meiosis, is defective in the neo-autotetraploid but robust in the established autotetraploid. The presented findings suggest that, initially, diploid-like interference fails to act effectively on multivalent pairing and accompanying pre-CO recombination interactions and that stable autopolyploid meiosis can emerge by evolution of a “supercharged” interference process, which can now act effectively on such configurations. Thus, the basic interference mechanism responsible for simplifying CO patterns along chromosomes in diploid meiosis has evolved the capability to also simplify CO patterns among chromosomes in autopolyploids, thereby promoting bivalent formation. We further show that evolution of stable autotetraploidy preadapts meiosis to higher ploidy, which in turn has interesting mechanistic and evolutionary implications.

Hyper-Recombinant Plants: An Emerging Field for Plant Breeding

Novelty is the primary requirement and breeding target for plant breeding, which can make a significant contribution to the new cultivar. The key factor for successful breeding is the genetic variation in the progeny, which depends on the degree of genetic material mixing after meiosis. However, meiotic recombination is tightly astricting in plants, resulting in a limited number of crossovers (COs). Recently, several anti-CO factors have been identified that limiting the meiotic recombination in plants, and the knock-out mutants displayed a significant increase in recombination frequency. This provides a universal tool to manipulate the meiotic recombination in plants by applying anti-CO genes, which will facilitate the breeding procedure. Due to the rapid development of genome sequencing and gene editing technologies, the genomes of more and more plants have been sequenced. In the meanwhile, the efficient CRISPR-Cas9 system has also been established in plants. Thus, it’s time to break the shackles of meiotic recombination to create novel cultivars in the biological era of genomics. Here we summarize the functional studies of the main meiotic recombination suppressors in plants, with the discussion of the possibility to apply the anti-CO genes in plant breeding as an emerging tool, especially for ornamental plant breeding.

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Mapping Recombination Landscape and Basidial Spore Number in the Button Mushroom Agaricus bisporus.

The button mushroom Agaricus bisporus is represented mainly by two varieties, a secondarily homothallic variety with predominantly two heterokaryotic spores per basidia and a heterothallic variety with predominantly four homokaryotic spored basidium. Both varieties also differ in their recombination landscape with the former showing crossovers (CO) predominantly at chromosome ends whereas the latter has a more evenly distribution of CO over the chromosomes. The two varieties are compatible, and this has been used to study segregation of the basidial spore number (BSN) and the genomic positions of recombination, i.e., the CO landscape, in order to find the underlying genetic determinants. Knowledge on genes controlling CO positions might facilitate either the conservation of favorable allele combinations or the disruption of unwanted allele combinations to reduce linkage drag. For BSN, in total seven QTL were found with the major QTL on chromosome 1 explaining ca. 55% of the phenotypic variation. It appeared, however, difficult to map the recombination landscape. This phenotype can only be assessed in the meiotic offspring of an intervarietal hybrid which is a laborious and difficult task. Nevertheless, this was done, and we were able to map three QTLs for this trait, two on chromosome 1 and one on chromosome 2 not overlapping with the QTL for BSN. The hurdles encountered are discussed and a new strategy is proposed that can solves these. We propose to use two genetically unrelated mapping populations both offspring of a cross between a var. bisporus and a var. burnettii homokaryon and thus segregating both for CO and BSN. Homokaryotic offspring of both populations can be intercrossed without limitation of mating incompatibility and marker homozygosity and the hybrid mushrooms directly used to map BSN. Homokaryotic offspring of these hybrid mushrooms can be genotypes to assess CO positions using next generation sequencing technologies that will solve marker problems encountered, especially for genotyping chromosome ends. This new approach can be a useful strategy for a more efficient breeding strategy for mushrooms in general.

Aging Negatively Impacts DNA Repair and Bivalent Formation in the C. elegans Germ Line.

Defects in crossover (CO) formation during meiosis are a leading cause of birth defects, embryonic lethality, and infertility. In a wide range of species, maternal aging increases aneuploidy and decreases oocyte quality. In C. elegans which produce oocytes throughout the first half of adulthood, aging both decreases oocytes quality and increases meiotic errors. Phenotypes of mutations in genes encoding double-strand break (DSB)-associated proteins get more severe with maternal age suggesting that early meiosis reflects a particularly sensitive node during reproductive aging in the worm. We observed that aging has a direct effect on the integrity of C. elegans meiotic CO formation, as observed by an increase of univalent chromosomes and fusions at diakinesis, with a considerable increase starting at 4 days. We also characterize the possible causes for the age-related changes in CO formation by analyzing both steady-state levels and kinetics of the ssDNA binding proteins RPA-1 and RAD-51. Profound reductions in numbers of both RPA-1 and RAD-51 foci suggests that both DSB formation and early meiotic repair are compromised in aging worms. Using laser microirradiation and γ-irradiation to induce exogenous damage, we show specifically that recruitment of these homologous recombination proteins is altered. Repair defects can be seen in two-and-one-half day-old adults making the loss of germline repair capacity among the earliest aging phenotypes in the worm.

Genome-wide variability in recombination activity is associated with meiotic chromatin organization.

Recombination enables reciprocal exchange of genomic information between parental chromosomes and successful segregation of homologous chromosomes during meiosis. Errors in this process lead to negative health outcomes, whereas variability in recombination rate affects genome evolution. In mammals, most crossovers occur in hotspots defined by PRDM9 motifs, although PRDM9 binding peaks are not all equally hot. We hypothesize that dynamic patterns of meiotic genome folding are linked to recombination activity. We apply an integrative bioinformatics approach to analyze how three-dimensional (3D) chromosomal organization during meiosis relates to rates of double-strand-break (DSB) and crossover (CO) formation at PRDM9 binding peaks. We show that active, spatially accessible genomic regions during meiotic prophase are associated with DSB-favored loci, which further adopt a transient locally active configuration in early prophase. Conversely, crossover formation is depleted among DSBs in spatially accessible regions during meiotic prophase, particularly within gene bodies. We also find evidence that active chromatin regions have smaller average loop sizes in mammalian meiosis. Collectively, these findings establish that differences in chromatin architecture along chromosomal axes are associated with variable recombination activity. We propose an updated framework describing how 3D organization of brush-loop chromosomes during meiosis may modulate recombination.

Evaluation of moxifloxacin in canine and non-human primate telemetry assays: Comparison of QTc interval prolongation by timepoint and concentration-QTc analysis.

The in vivo correct QT (QTc) assay is used by the pharmaceutical industry to characterize the potential for delayed ventricular repolarization and is a core safety assay mentioned in International Conference on Harmonization (ICH) S7B guideline. The typical telemetry study involves a dose‐response analysis of QTc intervals over time using a crossover (CO) design. This method has proven utility but does not include direct integration of pharmacokinetic (PK) data. An alternative approach has been validated and is used routinely in the clinical setting that pairs pharmacodynamic (PD) responses with PK exposure (e.g., concentration‐QTc (C‐QTc) analysis. The goal of our paper was to compare the QTc sensitivity of two experimental approaches in the conscious dog and non‐human primate (NHP) QTc assays. For timepoint analysis, a conventional design using eight animals (8 × 4 CO) to detect moxifloxacin‐induced QTc prolongation was compared to a PK/PD design in a subset (N = 4) of the same animals. The findings demonstrate that both approaches are equally sensitive in detecting threshold QTc prolongation on the order of 10 ms. Both QTc models demonstrated linearity in the QTc prolongation response to moxifloxacin dose escalation (6 to 46 ms). Further, comparison with human QTc findings with moxifloxacin showed agreement and consistent translation across the three species: C‐QTc slope values were 0.7‐ (dog) and 1.2‐ (NHP) fold of the composite human value. In conclusion, our data show that dog and NHP QTc telemetry with an integrated PK arm (C‐QTc) has the potential to supplement clinical evaluation and improve integrated QTc risk assessment.

Caenorhabditis elegans RMI2 functional homolog-2 (RMIF-2) and RMI1 (RMH-1) have both overlapping and distinct meiotic functions within the BTR complex.

Homologous recombination is a high-fidelity repair pathway for DNA double-strand breaks employed during both mitotic and meiotic cell divisions. Such repair can lead to genetic exchange, originating from crossover (CO) generation. In mitosis, COs are suppressed to prevent sister chromatid exchange. Here, the BTR complex, consisting of the Bloom helicase (HIM-6 in worms), topoisomerase 3 (TOP-3), and the RMI1 (RMH-1 and RMH-2) and RMI2 scaffolding proteins, is essential for dismantling joint DNA molecules to form non-crossovers (NCOs) via decatenation. In contrast, in meiosis COs are essential for accurate chromosome segregation and the BTR complex plays distinct roles in CO and NCO generation at different steps in meiotic recombination. RMI2 stabilizes the RMI1 scaffolding protein, and lack of RMI2 in mitosis leads to elevated sister chromatid exchange, as observed upon RMI1 knockdown. However, much less is known about the involvement of RMI2 in meiotic recombination. So far, RMI2 homologs have been found in vertebrates and plants, but not in lower organisms such as Drosophila, yeast, or worms. We report the identification of the Caenorhabditis elegans functional homolog of RMI2, which we named RMIF-2. The protein shows a dynamic localization pattern to recombination foci during meiotic prophase I and concentration into recombination foci is mutually dependent on other BTR complex proteins. Comparative analysis of the rmif-2 and rmh-1 phenotypes revealed numerous commonalities, including in regulating CO formation and directing COs toward chromosome arms. Surprisingly, the prevalence of heterologous recombination was several fold lower in the rmif-2 mutant, suggesting that RMIF-2 may be dispensable or less strictly required for some BTR complex-mediated activities during meiosis.

The synaptonemal complex central region modulates crossover pathways and feedback control of meiotic double-strand break formation.

The synaptonemal complex (SC) is a proteinaceous structure that mediates homolog engagement and genetic recombination during meiosis. In budding yeast, Zip-Mer-Msh (ZMM) proteins promote crossover (CO) formation and initiate SC formation. During SC elongation, the SUMOylated SC component Ecm11 and the Ecm11-interacting protein Gmc2 facilitate the polymerization of Zip1, an SC central region component. Through physical recombination, cytological, and genetic analyses, we found that ecm11 and gmc2 mutants exhibit chromosome-specific defects in meiotic recombination. CO frequencies on a short chromosome (chromosome III) were reduced, whereas CO and non-crossover frequencies on a long chromosome (chromosome VII) were elevated. Further, in ecm11 and gmc2 mutants, more double-strand breaks (DSBs) were formed on a long chromosome during late prophase I, implying that the Ecm11–Gmc2 (EG) complex is involved in the homeostatic regulation of DSB formation. The EG complex may participate in joint molecule (JM) processing and/or double-Holliday junction resolution for ZMM-dependent CO-designated recombination. Absence of the EG complex ameliorated the JM-processing defect in zmm mutants, suggesting a role for the EG complex in suppressing ZMM-independent recombination. Our results suggest that the SC central region functions as a compartment for sequestering recombination-associated proteins to regulate meiosis specificity during recombination.

OsMLH1 interacts with OsMLH3 to regulate synapsis and interference-sensitive crossover formation during meiosis in rice

Meiotic recombination is essential for reciprocal exchange of genetic information between homologous chromosomes and their subsequent proper segregation in sexually reproducing organisms. MLH1 and MLH3 belong to meiosis-specific members of the MutL-homolog family, which are required for normal level of crossovers (COs) in some eukaryotes. However, their functions in plants need to be further elucidated. Here, we report the identification of OsMLH1 and reveal its functions during meiosis in rice. Using CRISPR-Cas9 approach, two independent mutants, Osmlh1-1 and Osmlh1-2, are generated and exhibited significantly reduced male fertility. In Osmlh1-1, the clearance of PAIR2 is delayed and partial ZEP1 proteins are not loaded into the chromosomes, which might be due to the deficient in resolution of interlocks at late zygotene. Thus, OsMLH1 is required for the assembly of synapsis complex. In Osmlh1-1, CO number is dropped by ~53% and the distribution of residual COs is consistent with predicted Poisson distribution, indicating that OsMLH1 is essential for the formation of interference-sensitive COs (class I COs). OsMLH1 interacts with OsMLH3 through their C-terminal domains. Mutation in OsMLH3 also affects the pollen fertility. Thus, our experiments reveal that the conserved heterodimer MutLγ (OsMLH1-OsMLH3) is essential for the formation of class I COs in rice.

ZYP1 is required for obligate cross-over formation and cross-over interference in Arabidopsis

The synaptonemal complex is a tripartite proteinaceous ultrastructure that forms between homologous chromosomes during prophase I of meiosis in the majority of eukaryotes. It is characterized by the coordinated installation of transverse filament proteins between two lateral elements and is required for wild-type levels of crossing over and meiotic progression. We have generated null mutants of the duplicated Arabidopsis transverse filament genes zyp1a and zyp1b using a combination of T-DNA insertional mutants and targeted CRISPR/Cas mutagenesis. Cytological and genetic analysis of the zyp1 null mutants reveals loss of the obligate chiasma, an increase in recombination map length by 1.3- to 1.7-fold and a virtual absence of cross-over (CO) interference, determined by a significant increase in the number of double COs. At diplotene, the numbers of HEI10 foci, a marker for Class I interference-sensitive COs, are twofold greater in the zyp1 mutant compared to wild type. The increase in recombination in zyp1 does not appear to be due to the Class II interference-insensitive COs as chiasmata were reduced by ∼52% in msh5/zyp1 compared to msh5 These data suggest that ZYP1 limits the formation of closely spaced Class I COs in Arabidopsis Our data indicate that installation of ZYP1 occurs at ASY1-labeled axial bridges and that loss of the protein disrupts progressive coalignment of the chromosome axes.

The synaptonemal complex imposes crossover interference and heterochiasmy in Arabidopsis

Meiotic crossovers (COs) have intriguing patterning properties, including CO interference, the tendency of COs to be well-spaced along chromosomes, and heterochiasmy, the marked difference in male and female CO rates. During meiosis, transverse filaments transiently associate the axes of homologous chromosomes, a process called synapsis that is essential for CO formation in many eukaryotes. Here, we describe the spatial organization of the transverse filaments in Arabidopsis (ZYP1) and show it to be evolutionary conserved. We show that in the absence of ZYP1 (zyp1azyp1b null mutants), chromosomes associate in pairs but do not synapse. Unexpectedly, in absence of ZYP1, CO formation is not prevented but increased. Furthermore, genome-wide analysis of recombination revealed that CO interference is abolished, with the frequent observation of close COs. In addition, heterochiasmy was erased, with identical CO rates in males and females. This shows that the tripartite synaptonemal complex is dispensable for CO formation and has a key role in regulating their number and distribution, imposing CO interference and heterochiasmy.

Comparative transcriptomic analysis of thermally stressed Arabidopsis thaliana meiotic recombination mutants

BackgroundMeiosis is a specialized cell division that underpins sexual reproduction in most eukaryotes. During meiosis, interhomolog meiotic recombination facilitates accurate chromosome segregation and generates genetic diversity by shuffling parental alleles in the gametes. The frequency of meiotic recombination in Arabidopsis has a U-shaped curve in response to environmental temperature, and is dependent on the Type I, crossover (CO) interference-sensitive pathway. The mechanisms that modulate recombination frequency in response to temperature are not yet known.ResultsIn this study, we compare the transcriptomes of thermally-stressed meiotic-stage anthers from msh4 and mus81 mutants that mediate the Type I and Type II meiotic recombination pathways, respectively. We show that heat stress reduces the number of expressed genes regardless of genotype. In addition, msh4 mutants have a distinct gene expression pattern compared to mus81 and wild type controls. Interestingly, ASY1, which encodes a HORMA domain protein that is a component of meiotic chromosome axes, is up-regulated in wild type and mus81 but not in msh4. In addition, SDS the meiosis-specific cyclin-like gene, DMC1 the meiosis-specific recombinase, SYN1/REC8 the meiosis-specific cohesion complex component, and SWI1 which functions in meiotic sister chromatid cohesion are up-regulated in all three genotypes. We also characterize 51 novel, previously unannotated transcripts, and show that their promoter regions are associated with A-rich meiotic recombination hotspot motifs.ConclusionsOur transcriptomic analysis of msh4 and mus81 mutants enhances our understanding of how the Type I and Type II meiotic CO pathway respond to environmental temperature stress and might provide a strategy to manipulate recombination levels in plants.

The Role of Chromatid Interference in Determining Meiotic Crossover Patterns

Plants, like all sexually reproducing organisms, create genetic variability by reshuffling parental alleles during meiosis. Patterns of genetic variation in the resulting gametes are determined by the independent assortment of chromosomes in meiosis I and by the number and positioning of crossover (CO) events during meiotic recombination. On the chromosome level, spatial distribution of CO events is biased by multiple regulatory mechanisms, such as CO assurance, interference and homeostasis. However, little is known about how multiple COs are distributed among the four chromatids of a bivalent. Chromatid interference (CI) has been proposed as a regulatory mechanism that biases distribution of multiple COs toward specific chromatid partners, however, its existence has not been well-studied and its putative mechanistic basis remains undescribed. Here, we introduce a novel method to quantitatively express CI, and take advantage of available tetrad-based genotyping data from Arabidopsis and maize male meiosis to quantify CI effects on a genome-wide and chromosomal scale. Overall, our analyses reveal random involvement of sister chromatids in double CO events across paired chromosomes, indicating an absence of CI. However, on a genome-wide level, CI was found to vary with physical distance between COs, albeit with different effects in Arabidopsis and maize. While effects of CI are minor in Arabidopsis and maize, the novel methodology introduced here enables quantitative interpretation of CI both on a local and genome-wide scale, and thus provides a key tool to study CI with relevance for both plant genetics and crop breeding.

Generalised Crossover

Crossover (CO) is a constraint on anaphoric dependencies, according to which, quantifier scope can feed pronominal anaphora unless the anaphoric expression precedes the quantifier. We demonstrate that effects reminiscent of CO arise with presupposition as well, and propose to generalise CO as follows: Projective content (quantifier scope, presupposition projection, etc.) feeds semantic dependencies (pronominal anaphora, presupposition satisfaction), unless the semantically dependent expression precedes the trigger of the projective content. We call this generalisation, Generalised Crossover (GCO). Although we cannot offer a full explanation for GCO in this paper, we will discuss its implications for recent theories of CO.

Suplementação aguda de arginina não influencia na hipotensão pós-exercício aeróbico

This study evaluated the effects of acute arginine supplementation (ARG) on post-exercise hypotension (HPE). For this, 12 physically active young men participated in this randomized, double-blind crossover clinical trial. All were submitted to two experimental conditions (ARG or placebo – PLA). 45 minutes after supplementation, all participants performed 30 minutes of moderate-intensity aerobic exercise (70-75% of reserve heart rate). Heart rate and systolic and diastolic blood pressures were measured before, 30 and 60 minutes after exercise. In comparison with pre-exercise means, there was a lower systolic blood pressure until to 60 min post-exercise (117.3±6.5 vs. 109.6±7.2 mmHg, p=0.001), lower mean arterial blood pressure (89.1±7.0 vs. 83.8±8.2 mmHg, p=0.024), increased heart rate (67.1±11.9 vs. 84.8±6.8 bpm, p=0.001) and the double product (7988±1372 vs. 9734±990 mmHg.bpm, p=0.006) until 30 min post-exercise. However, there was no significant difference between experimental conditions. Using the methods applied, our results demonstrated no effect of acute ARG supplementation on aerobic HPE in physically active young men.