Endurance, which is dependent at least partly upon the activation of the brain cortex, is important for performance in rowing. Transcranial direct current stimulation (tDCS) has shown benefits for endurance, but its effects on the endurance performance of elite rowing athletes are unknown, and are examined in this study. Eight elite female rowers completed 5 km of rowing on an ergometer following stimulation of the tDCS and sham over motor cortices. Each session lasted 20 min and the current was set at 2.2 mA. Time, 500 m/split, power, time corresponding to 500 m (TC500) and power corresponding to 500 m (PC500) were recorded continuously throughout the tests. No significant differences in time, 500 m/split and power were observed between baseline, tDCS and sham. Compared to the sham, tDCS induced a percentage reduction in TC500 from baseline to 2500 m and 4000 m, and a percentage increase in PC500 from baseline to 500 m, 1000 m, 1500 m, 2000 m, 2500 m, 4000 m, 4500 m and 5000 m. One-session tDCS did not have significant benefits for rowing endurance performance in elite professional rowers, and had only marginally greater efficacy compared to sham. These findings offer knowledge helpful to the design of future studies exploring the effects of tDCS on the endurance performance of elite rowers. Endurance capacity, which depends upon aerobic metabolism, is critical to performance in rowing . TradititDCS is one such technique that can non-invasively and safely modulate cortical activities by sending direct micro-level currents to the targeted regions via scalp electrodes ,10. In rBy using the Halo Sport system of tDCS, Park et al.  showed tTherefore, we have here completed a pilot, single-blinded study consisting of eight elite athletes from the national rowing team of China and tested the effects of one-session tDCS targeting M1 via the Halo system on endurance performance. We hypothesized that, compared to the sham, tDCS would induce significantly greater endurance performance during rowing  in these elite athletes.Eight national female rowers  volunteered for this study. The eligibility criteria were (1) sculling techniques, (2) competitive performance ranking in the top 8 in the national regatta and (3) the regular completion of daily training. Rowers were not included in this study if they had any lower-limb and/or lower-back injury or pain within six months before the study. Each rower and her coach were informed of the experimental procedure and invited to provide their informed consent to participate in this study. The study protocol was approved by the institutional review board committee of Shanghai University of Sport (102772019RT020).The rowers visited the training center three times, which included one baseline visit to measure endurance performance and two intervention visits. Participants were selected in a single-blinded, parallel, randomized, counterbalanced order to receive tDCS and sham stimulation. The rowers were asked to not consume coffee or alcohol and to sleep for at least 7 h before and during the test period. All visits were separated by at least 72 h, and each visit was arranged at the same time of the day.During the first visit, the rowers were familiarized with the experimental procedures, and we set up the drag factor on the air damper of a rowing ergometer, which prevented any changes over the following 2–3 visits. In addition, the athletes executed a 5 km endurance test on a rowing ergometer to establish individual baseline performance. In this test, the rowers first performed a warm-up exercise for 15 min, followed by 5 km of rowing with a constant load at a 20 stroke/rate (SR). In visits 2–3, the rowers received the tDCS/sham stimulations via Halo Sport for 20 min after a warm up, and completed a constant-load 5 km row at 20 SR. During rowing, the rowers were allowed to receive verbal encouragement from performance coaches in order to achieve optimal performance.The tDCS was administered by Halo Sport  with three foam electrodes (size 4 × 6 cm) wetted with 0.9% NaCl that contained an electric current stimulator, driven by a lithium-ion (LiPo) cell (36 V). The tDCS montage was similar to that used by Huang et al. , which hAt baseline and after the tDCS/sham stimulation, the rowers performed a constant-load 5 km row at 20 SR on a rowing ergometer . The 5 km row was preceded by a warm-up exercise lasting 15 min, as per the training plan given by the strength and conditioning coach. The rowers were verbally encouraged throughout the 5 km row by their performance coaches. Visual feedback of their performance was given by the PM5 display setting on the rowing ergometer . Time, 500 m/split, power, time corresponding to 500 m (TC500) and power corresponding to 500 m (PC500) were recorded, respectively, using MP5. All parameter data were exported using the Concept 2 utility .p < 0.05. Statistical analysis was performed via SPSS 26.0 .Unless specified, data are presented as mean ± SD. The normality of distribution was checked using the Shapiro–Wilk test, and the sphericity was checked using Mauchly’s test; the Greenhouse–Geiiser test was used to determine when the results violated the Mauchly’s test. A paired-sample t test was used to compare performance between two intervention visits. One-way ANOVA was used to compare the effects of tDCS on the time, 500 m/split and power between baseline, tDCS and sham conditions during 5 km of rowing. The post-hoc analysis of the Tukey test was used to check where there was statistical significance. The linear mixed-effects model was used to examine the effects of tDCS on TC500 and PC500 during the 5 km row. Statistical significance was set at t = −0.421, p = 0.685).All participants completed all the tests. No side effects or injuries were reported. No significant difference was observed in endurance time between two intervention visits, during which the interventions were operated in a counterbalanced order (p = 0.780), 500 m/split  or power  between baseline, tDCS and sham  and 4000 m ; that is, after receiving tDCS, the TC500 was significantly shorter than that after sham , 1000 m , 1500 m , 2000 m , 2500 m , 4000 m , 4500 m  and 5000 m .The linear mixed-effects models revealed significant differences in the percent changes in TC500 between tDCS and sham at 2500 m   are needn = 8) is the most significant limitation of this study, as it induced high inter-subject variance and affected the statistical power, resulting in non-significant results. It is thus necessary to explore methods to measure the effects of tDCS in elite athletes. The second limitation of this study is the influence of the electrical field. We found that both lower- and upper-limb motor areas were stimulated by the montage used in Halo Sport, depending on the stimulation of the electrical field. However, we could not confirm which contributes more to rowing endurance performance. This should thus be confirmed in the future. The third limitation of this study is the lack of any statistical analysis of the placebo effect. Because it is important to estimate how placebo effects influenced the results, these should be analyzed in the future. The last limitation of this study is the lack of neurophysiological assessments performed to characterize the underlying neurophysiological changes induced by tDCS. Previous studies reported that endurance exercise requires an increase in the input into the spinal motor neurons in order to produce muscle force and power continually [The small, single-gender sample size (athlete: female rowers, tinually . This istinually . Activattinually  via enhatinually , delayintinually ,32. Ther


Scenedesmus has been known to be one such microalga that can promote plant growth by secretion of auxin or cytokinin hormone analogs. However, no research has been performed on the effect of microalgae treatment on plant microbiota communities. This study was conducted to investigate the mode of action of microalgae as biostimulants in a plant microbiota perspective by using Scenedesmus sp. CHK0059 , which has been well documented as a biostimulant for strawberries. The strawberry cultivar Keumsil was bred with Seolhyang and Maehyang as the parent cultivars. Using these three cultivars, microbiota communities were evaluated for changes in structural composition according to the CHK0059 treatment. CHK0059-treated Seolhyang, and CHK0059-untreated Maehyang were similar in microbial diversity in the endosphere. From a microbiota community perspective, the diversity change showed that CHK0059 was affected by the characteristics of the host. Conversely, when CHK0059 treatment was applied, populations of Streptomyces and Actinospica were observed in the crown endosphere.Microalgae are photosynthetic cyanobacteria and eukaryotic microorganisms, mainly living in the water. In agriculture, numerous studies have been conducted to utilize microalgae as a biostimulant resource.  Chlorella, Chlamydomonas, and Scenedesmus are under active study for use in sustainable agriculture [Chlorella, Scenedesmus, and Chlamydomonas are all known to produce diverse bioactive metabolites and have a high potential to be beneficial for various crops [5As the global population is expected to increase to 9.8 billion by 2050, food shortages caused by environmental destruction and gaps in agricultural lands are expected to become more and more severe . For theiculture , 4. Chlos crops 5.Scenedesmus sp. CHK0059, the strain used in this study, is a single cell known by the species name Chlorella fusca, the genus of which was reclassified based on physiological, biochemical, and genetic characteristics [Scenedesmus is also an evolutionarily important microalga because some of the mitochondrial codons are non-standard, placing it in a different class Chlorophyceae [Scenedesmus obiliquus have been evaluated to increase the seed germination, root development, and cotyledon expansion of certain plants [Colletotrichum orbiculare was reported [Arabidopsis [Erinus alpines, CHK0059 exhibited an anti-aging effect [eristics . Genus Sn plants . As a pln plants . Inducedreported , and D-lbidopsis . Additiog effect .In general, multicellular organisms have precise interactions between the organisms and their surrounding or inner microorganisms. The term ‘microbiota’ comes from seeing one organic and complex relationship as an integrated complex organism . BacteriFragariae × ananassa) are also reported to be affected by CHK0059 treatment [The strain CHK0059 has been shown to have significant positive effects on many crops, and strawberries . CHK0059 at an average 1.82 × 107 cells/ml concentration was diluted 9:1 with distilled water and treated 100 ml/plant twice a week, and the same volume of 1× Hogland solution was treated once a week. The strawberry plants were cultivated for 40 days, and they were drenched with CHK0059 10 times during the cultivation period. After 40 days, strawberry rhizosphere soil, root tissue, and crown tissue samples were collected to analyze microbiota community structures (n = 5).Strawberry plant cultivars Maehyang, Seolhyang, and Keumsil were cultivated in a greenhouse at Gyeongsang National University, Jinju, Republic of Korea (35°9'17" N 128°5'56"E). Seolhyang is the most widely cultivated strawberry cultivar in Korea, and Maehyang is mainly cultivated in the southern region of Korea for export. Keumsil was developed for export by complementing the shortcomings of Maehyang as a crossbreed of Seolhyang and Maehyang. Therefore, this study attempted to understand microbial community structure resulting from microalgae treatment of three strawberry cultivars. CHK0059 strain was obtained from the Rural Development Administration (Korea), and the microalgae culture medium is a product from F&B Nature Co., Ltd., (Korea). The CHK0059 was initially inoculated at 1 × 10CHK0059-treated and -untreated strawberry rhizosphere, root endosphere, and crown endosphere were used for microbiota community analyses. Before the isolation of microbiota DNA, the strawberry rhizosphere was collected by shaking after tapping and removing the excess soil that was not close to the roots. The root and crown were then dissected. Next, the root was washed with flowing water, and the crown was cut by about two to five millimeters. To prevent contamination due to this series of tasks, the tissues were disinfected in 70% ethyl alcohol for 30 s, and then 1% NaOCl for 30 s. The disinfected tissues were dried on a clean bench for 1 h followed by rinsing with autoclaved distilled water. DNA extraction was carried out by FastDNA SPIN Kit for Soil  with 0.5 g rhizosphere or 0.4 g endosphere of each tissue. Extracted DNA quality and quantity were checked at 230 nm, 260 nm, and 280 nm light wave using a spectrometer , and the DNA concentration was set to 5-8 ng/μl. Amplification of 16S rRNA V4 region using PCR was proceeded by Illumina adapter linked primer, 515F (5’-TCGTCGGCAGCGTCAGATGTGTATAAGAGACAGG TGCCAGCMGCCGCGGTAA) and 805R (5’-GTCTCGTGGGCTCGGAGATGTGTATAAGAGACAGGAC TACHVGGGTATCTAATCC), the final dose of which was 0.4 μM. To restrain amplification of the mitochondrial and chloroplast sequences of the host, 0.75 μM of plastid peptide nucleic acid (5’-GGCTCAACCCTGGACAG) and mitochondrial peptide nucleic acid (5’-GGCAAGTGTTCTTCGGA) clamps were used. The DNA polymerase and its buffer solution were KAPA HiFi HotStart ReadyMix . Temperature conditions of the chain reactions were 95°C for 3 min in initial denaturation, 95°C for 30 s in repeated denaturation, 55°C for 30 s in repeated annealing, 72°C for 30 s in repeated elongation, and 72°C for 5 min in final elongation. The repeated chain stage was 25°C in the rhizosphere sample, and 28-30°C in the endosphere sample. The amplified V4 region was provided by Macrogen Inc. (Republic of Korea) and sequenced by Illumina MiSeq 2 × 300 bp.The fastq files of the MiSeq 2 × 300 bp results were handled and computed by R (4.1.3 version) on Ubuntu20.04 in the windows subsystem for Linux 2 on Windows 11 installed on a personal computer with 32 GiB DDR4 RAM and AMD Ryzen 9 5950X. The reads were conducted by denoising amplicon sequence variants and clustered using DADA2 (1.20.0 version)  and the Burkholderiaceae, Caulobacteraceae, Sphingomonadaceae, Enterobacteriaceae, Streptomycetaceae, Rhodocyclaceae, Rhizobiaceae, Chitinophagaceae, Rhodanobacteraceae, and Pseudomonadaceae  is observed, ASV means mainly richness, while Shannon’s and Simpson’s diversity indices pertain to both richness and evenness appropriately. The crown endospheres of cultivars Maehyang and Seolhyang differed significantly in the observed ASV and the Shannon diversity index. However, the indices showed that Maehyang was increased and Syeolhyang was decreased by the CHK0059 treatment . By the To comprehend the difference of the CHK0059 impact on bacterial community diversity of each cultivar, the abundance of the taxonomic group, which was computed by the most detailed identification result of each ASV, was compared by ANCOM-BC  . SignifiBrevibacterium was more abundant in the treated groups, mostly in the root endosphere, and Candidatus, Koribacter, Actinospica, Brevibacterium, Streptomyces, Nubsella, WD2101 soil group, Rhodopila, Limnobacter, Luteibacter, and Stenotrophomonas were more abundant in the treated groups, commonly in the crown endosphere. Pirellula and Hyphomicrobiaceae were more abundant in the untreated group in the crown. In addition, the Pearson correlation analysis with the corresponding taxa confirmed that Streptomyces and Actinospica had a positive correlation with the CHK0059 treatment because the changes were more commonly observed in the crown (To discover the increases of bacteria in the CHK0059-treated or –untreated groups among the three strawberry cultivars, ANCOM-BC was also conducted for all cultivars . Treatmehe crown , Fig. S2Scenedesmus CHK0059, which has been well documented as a plant biostimulant [Microalgae are well reported as effective plant biostimulants and biological control agents against fungal pathogens, nematodes, and even viruses , 7. Thistimulant , althougBurkholderiaceae, Caulobacteraceae, Sphingomonadaceae, Enterobacteriaceae, Streptomycetaceae, Rhodocyclaceae, Rhizobiaceae, Chitinophagaceae, Rhodanobacteraceae, and Pseudomonadaceae, regardless of whether CHK0059 treatment was applied or not. The effect of CHK0059 on alpha diversity was observed to have changed the richness of the crown endosphere microbiota cultivars Maehyang and Seolhyang. When evaluated from the perspective of beta diversity, distribution in PCoA results showed division by composition. Intriguingly, changes in microbiota community structure by application of CHK0059 were detected in the crown endosphere, but not in the rhizosphere, regardless of the strawberry cultivars. The results support a previous finding that the application Chlorella vulgaris did not affect bacterial diversity in the bean rhizosphere [Metagenomic 16S rRNA amplicon analyses revealed that the dominant bacterial taxa in the tissue composition of strawberry were zosphere . Unfortuzosphere .Based on the result of PERMANOVA, the 18 groups based on the cultivars, compositions, and CHK0059 treatment were judged that at least one of them was distinguished at the Bray-Curtis distance. In pair-wise PERMANOVA as a post hoc test of the results, treated and untreated endosphere sample distribution of each cultivar Seolhyang and Maehyang, the parent cultivars of Keumsil, was distinguished significantly, and their PCoA results showed that their positions were opposite. On the other hand, interestingly, CHK0059-untreated Seolhyang and CHK0059-treated Maehyang, CHK0059-treated Seolhyang, and CHK0059-untreated Maehyang were similar in endosphere composition. For a more complete picture, the three cultivars were analyzed by differential analysis at the taxa level and Venn diagrams and tile plots summarized the results. These results presented the microbiota community change as more apparent; Keumsil was less affected by CHK0059 than the other two cultivars. Seolhyang and Maehyang had many abundances of different taxonomies. Diversity and Venn diagram results clearly showed that the endospheres of cultivars Seolhyang and Maehyang had the opposite trend with and without the CHK0059 treatment. The different reaction phenomena may be due to genetic differences between the cultivars.Brevibacterium was detected as an abundant bacterium in the root endosphere by CHK0059 treatment. Application of Brevibacterium diminature with microalgae mixture enhanced rice yield up to 1.2-fold compared to no application [Streptomyces and Actinospica, were correlated with the CHK0059 treatment. In many cases, the correlation analysis does not specify causality well enough, but this study was planned with the CHK0059 treatment as the independent variable, and the dependent variable was community changes. Therefore, it was judged that the increase of Actinospica and Streptomyces was due to the CHK0059 treatment. Although these results indicated that CHK0059 has an effect of increasing the population density of certain microbes in the community, more in-depth research is required to address which mechanisms may involve the buildup of the beneficial microbe density in the system.Microalgae are known to promote plant growth and protect plants from biotic and abiotic stresses by producing plant hormones, D-lactic acid, toxin, antibiotic metabolites, and ISR . Howeverlication . In the Streptomyces and Actinospica to prevail in the bacterial community. In addition, Actinospica and Streptomyces, which belong in Actinomycetia, were reported to be important for tolerance and phytoremediation of heavy metal pollution [Streptomyces also reported well on plant growth promotion [This study displayed two major microbiota community changes in strawberry by CHK0059 treatment. One was the bacteria varied according to the cultivar during the CHK0059 treatment or not, which was probably a case in which the bacteria phase changed due to the interaction between the CHK0059 and the plant. Also, the beta diversity interactions of CHK0059, which showed opposite tendency between Seolhyang and Maehyang, and the beta diversity interaction of Keumsil, which fell somewhere in the middle, suggest the possibility that the beta diversity was considered as a kind of phenotype. The other was the common increase in bacterial taxa by the CHK0059 treatment. CHK0059 probably interacted directly without the host factor, and CHK0059 was helping ollution . Streptoromotion -27 becau