Plants interact with root microbes via chemical signaling, which modulates competence or symbiosis. Although several volatile organic compounds (VOCs) from fungi may affect plant growth and ...development, the signal transduction pathways mediating VOC sensing are not fully understood. 6‐pentyl‐2H‐pyran‐2‐one (6‐PP) is a major VOC biosynthesized by Trichoderma spp. which is probably involved in plant–fungus cross‐kingdom signaling. Using microscopy and confocal imaging, the effects of 6‐PP on root morphogenesis were found to be correlated with DR5:GFP, DR5:VENUS, H2B::GFP, PIN1::PIN1::GFP, PIN2::PIN2::GFP, PIN3::PIN3::GFP and PIN7::PIN7::GFP gene expression. A genetic screen for primary root growth resistance to 6‐PP in wild‐type seedlings and auxin‐ and ethylene‐related mutants allowed identification of genes controlling root architectural responses to this metabolite. Trichoderma atroviride produced 6‐PP, which promoted plant growth and regulated root architecture, inhibiting primary root growth and inducing lateral root formation. 6‐PP modulated expression of PIN auxin‐transport proteins in a specific and dose‐dependent manner in primary roots. TIR1, AFB2 and AFB3 auxin receptors and ARF7 and ARF19 transcription factors influenced the lateral root response to 6‐PP, whereas EIN2 modulated 6‐PP sensing in primary roots. These results indicate that root responses to 6‐PP involve components of auxin transport and signaling and the ethylene‐response modulator EIN2.
Summary
Phosphate (Pi) is a critical macronutrient for the biochemical and molecular functions of cells. Under phosphate limitation, plants manifest adaptative strategies to increase phosphate ...scavenging. However, how low phosphate sensing links to the transcriptional machinery remains unknown.
The role of the MEDIATOR (MED) transcriptional co‐activator, through its MED16 subunit in Arabidopsis root system architecture remodeling in response to phosphate limitation was assessed. Its critical function acting over the SENSITIVE TO PROTON RHIZOTOXICITY1 (STOP1)‐ALUMINUM‐ACTIVATED MALATE TRANSPORT1 (ALMT1) signaling module was tested through a combination of genetic, biochemical, and genome‐wide transcriptomic approaches.
Root system configuration in response to phosphate scarcity involved MED16 functioning, which modulates the expression of a large set of low‐phosphate‐induced genes that respond to local and systemic signals in the Arabidopsis root tip, including those directly activated by STOP1. Biomolecular fluorescence complementation analysis suggests that MED16 is required for the transcriptional activation of STOP1 targets, including the membrane permease ALMT1, to increase malate exudation in response to low phosphate.
Our results unveil the function of a critical transcriptional component, MED16, in the root adaptive responses to a scarce plant macronutrient, which helps understanding how plant cells orchestrate root morphogenesis to gene expression with the STOP1‐ALMT1 module.
ABSTRACTCastillo, D, Raya-González, J, Weston, M, and Yanci, J. Distribution of external load during acquisition training sessions and match play of a professional soccer team. J Strength Cond Res ...XX(X)000–000, 2019—The aim of this study was to use global position systems to analyze the external loads of the 3 different acquisition training sessions (ATS) with competitive matches in professional soccer players over a 6-week period. Sixteen professional soccer players participated in the study, which analyzed the distribution of external load during the training microcycle of a professional soccer team. The 3 types of ATS undertaken by the players were as followsATS1 (strength), ATS2 (endurance), and ATS3 (speed). The total distance covered, the distance covered at above 14 km·h, the distance covered >21 km·h, the number of high accelerations (>3 m·s), and player load were recorded. The results showed that external loads were consistently higher during matches when compared with all training sessions (range of effect sizes1.06–3.38). Between training session comparisons revealed higher external loads during ATS1 and ATS2, when compared with ATS3 (range of effect sizes0.60–2.41). The only external load variable that differed between ATS1 and ATS2 was the distance covered >21 km·h, which was higher for ATS1. Our findings suggest that technical staff should consider the physical demands of weekly periodization to understand the training process regarding optimizing player physical performance.
Low phosphate (Pi) availability constrains plant development and seed production in both natural and agricultural ecosystems. When Pi is scarce, modifications of root system architecture (RSA) ...enhance the soil exploration ability of the plant and lead to an increase in Pi uptake. In Arabidopsis, an iron-dependent mechanism reprograms primary root growth in response to low Pi availability. This program is activated upon contact of the root tip with low-Pi media and induces premature cell differentiation and the arrest of mitotic activity in the root apical meristem, resulting in a short-root phenotype. However, the mechanisms that regulate the primary root response to Pilimiting conditions remain largely unknown. Here we report on the isolation and characterization of two low-Pi insensitive mutants (lpi5 and lpi6), which have a long-root phenotype when grown in low-Pi media. Cellular, genomic, and transcriptomic analysis of low-Pi insensitive mutants revealed that the genes previously shown to underlie Arabidopsis Al tolerance via root malate exudation, known as SENSITIVE TO PROTON RHIZOTOXICITY (STOP1) and ALUMINUM ACTIVATED MALATE TRANSPORTER 1 (ALMT1), represent a critical checkpoint in the root developmental response to Pi starvation in Arabidopsis thaliana. Our results also show that exogenous malate can rescue the long-root phenotype of lpi5 and lpi6. Malate exudation is required for the accumulation of Fe in the apoplast of meristematic cells, triggering the differentiation of meristematic cells in response to Pi deprivation.
The rhizosphere is the soil-plant interface colonized by bacterial and fungal species that exert growth-promoting and adaptive benefits. The plant-bacteria relationships rely upon the perception of ...volatile organic compounds (VOCs), canonical phytohormones such as auxins and cytokinins, and the bacterial quorum sensing-related N-acyl-L-homoserine lactones and cyclodipeptides. On the other hand, plant-beneficial Trichoderma fungi emit highly active VOCs, including 6-pentyl-2H-pyran-2-one (6-PP), and β-caryophyllene, which contribute to plant morphogenesis, but also into how these microbes spread over roots or live as endophytes. Here, we describe recent findings concerning how compounds from beneficial bacteria and fungi affect root architecture and advance into the signaling events that mediate microbial recognition.
The DNA damage response avoids mutations into dividing cells. Here, we analysed the role of photoreceptors on the restriction of root growth imposed by genotoxic agents and its relationship with cell ...viability and performance of meristems. Comparison of root growth of Arabidopsis WT, phyA-211, phyB-9, and phyA-211phyB-9 double mutants unveiled a critical role for phytochrome A (PhyA) in protecting roots from genotoxic stress, regeneration and cell replenishment in the meristematic zone. PhyA was located on primary root tips, where it influences genes related to the repair of DNA, including ERF115 and RAD51. Interestingly, phyA-211 mutants treated with zeocin failed to induce the expression of the repressor of cell cycle MYB3R3, which correlated with expression of the mitotic cyclin CycB1, suggesting that PhyA is required for safeguarding the DNA integrity during cell division. Moreover, the growth of the primary roots of PhyA downstream component HY5 and root growth analyses in darkness suggest that cell viability and DNA damage responses within root meristems may act independently from light and photomorphogenesis. These data support novel roles for PhyA as a key player for stem cell niche maintenance and DNA damage responses, which are critical for proper root growth.
•Physical fitness is greater in older youth basketball players.•Match activity vary across age categories in youth basketball.•Younger adolescent players with superior fitness exhibit higher external ...responses.•Older adolescent players emphasize in vertical and horizontal power expression.•Coaches should implement targeted training strategies for each age category.
This study aimed to: 1) compare physical fitness attributes and the external demands encountered during simulated matches in youth basketball players between age categories (under 14 years U14, under 16 years U16, and under 18 years U18), and 2) examine the relationships between physical fitness attributes and external demands during simulated matches in each age category. Thirty young basketball players categorized according to age (U14, n = 10; U16, n = 10; and U18, n = 10) completed a fitness test battery consisting of linear sprint, change-of-direction speed, repeated-change-of-direction speed, and jump assessments, and simulated matches monitored using local positioning system technology one week later. One‐way analyses of variance (ANOVA) with Bonferroni post hoc tests, as well as Cohen's effect sizes were used to compare physical fitness attributes and external match demands between age categories. Pearson's correlations and linear regression analyses were performed to quantify the relationships and shared variance between physical fitness attributes and external match demands in each age category. U14 players possessed lower (p <0.05, large-very large effects) physical fitness across all tests and performed less (p <0.05, large-very large effects) high-speed running (18.1–24.0 km•h − 1) during simulated matches than U16 and U18 players. Physical fitness attributes were significantly associated with external variables during simulated matches in each category, particularly in U14 players. These findings suggest coaches should implement training strategies targeting specific fitness attributes according to age in youth basketball players.
Summary
The Mediator (MED) complex plays a key role in the recruitment and assembly of the transcription machinery for the control of gene expression. Here, we report on the role of MEDIATOR18 ...(MED18) subunit in root development, auxin signaling and meristem cell viability in Arabidopsis thaliana seedlings. Loss‐of‐function mutations in MED18 reduce primary root growth, but increase lateral root formation and root hair development. This phenotype correlates with alterations in cell division and elongation likely caused by an increased auxin response and transport at the root tip, as evidenced by DR5:GFP, pPIN1::PIN1‐GFP, pPIN2::PIN2‐GFP and pPIN3::PIN3‐GFP auxin‐related gene expression. Noteworthy, med18 seedlings manifest cell death in the root meristem, which exacerbates with age and/or exposition to DNA‐damaging agents, and display high expression of the cell regeneration factor ERF115. Cell death in the root tip was reduced in med18 seedlings grown in darkness, but remained when only the shoot was exposed to light, suggesting that MED18 acts to protect root meristem cells from local cell death, and/or in response to root‐acting signal(s) emitted by the shoot in response to light stimuli. These data point to MED18 as an important component for auxin‐regulated root development, cell death and cell regeneration in root meristems.
Significance statement
Plant growth and adaptation rely on the activity of meristems. Here, we show that the MEDIATOR subunit 18 (MED18) is critical for viability of root proliferative cells controlling the balance between cell death and differentiation, and demonstrate that light perception in the shoot influences the stability and DNA repair mechanisms in root meristems.
Handball is a team sport in which players are exposed to high physical conditioning requirements and several contacts and collisions, so they must face various musculoskeletal injuries throughout ...their career. The aim of this study was to summarize the characteristics of handball injuries both in training and in competition contexts, differentiating by gender and age. A systematic review was conducted and a total of 15 studies (33 cohorts) met the inclusion criteria. Higher injury incidence was reported during matches compared to training sessions in all groups (i.e., male and female senior and youth players), with male senior players presenting the greatest values. Lower extremities were more frequently injured, being contusions and sprains the most common type of injuries. Females reported more serious injuries than males, who presented a higher percentage of acute injuries caused by direct contact, while in female players these injuries were not caused by direct contact actions. Wings and backs presented the highest injury incidence; additionally, players registered higher match incidence during international championships compared to national leagues. Due to the differences in the injury profile of handball players, specific preventive strategies should be implemented for each group to optimize the injury prevention process.
Considering nutrition education interventions have been frequently implemented in team sport athletes and have shown promising results, this study aimed to summarize the effects of nutrition ...education interventions on eating habits, nutrition knowledge, body composition, and physical performance in team sport athletes. A systematic review was conducted using the following databases: PubMed/MEDLINE, Web of Science and SPORTDiscus. A total of 14 studies met the inclusion criteria for the review. The methodological quality of included studies was evaluated, and each study was assessed according to the analyzed variables (i.e., eating habits, nutrition knowledge, body composition, and physical performance). Most studies showed improvements in or maintenance of variables used to indicate eating habits, nutrition knowledge, and body composition. However, limited studies examined the effect of nutrition education interventions on physical performance, with existing studies demonstrating disparate results. These findings suggest implementation of nutrition education interventions in team sport athletes could be an effective strategy to improve their eating habits, nutrition knowledge, and body composition. Due to the heterogeneity across the included studies regarding sport modality, competition level, age, and sex of the athletes investigated, as well as the intervention type adopted (i.e., online or face-to-face), it is difficult to establish optimal nutrition education interventions for each analyzed variable.
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