Transcriptomics Reveals the Molecular Basis for Methyl Jasmonate to Promote the Synthesis of Monoterpenoids in Schizonepeta tenuifolia Briq.

BACKGROUND: Methyl jasmonate has an important effect on the synthesis of plant secondary metabolites. Schizonepeta tenuifolia Briq. has a wide range of pharmacological effects and the secondary metabolites are dominated by monoterpenes (pulegone, menthone). OBJECTIVE: It is essential to determine the changes in secondary metabolites in S. tenuifolia under methyl jasmonate treatment and to probe the molecular mechanism. This can improve the accumulation of secondary metabolites in the medicinal plant S. tenuifolia and enrich the information gene expression at different MeJA levels, which can help to elucidate the molecular mechanism of monoterpenoid synthesis in S. tenuifolia. METHODS: In this study, we determined the changes in the content of monoterpenoids in S. tenuifolia under methyl jasmonate treatment. Meanwhile, we established a transcriptome database of S. tenuifolia under methyl jasmonate level using high-throughput sequencing. RESULTS: A certain concentration of MeJA promoted the accumulation of monoterpenoids in S. tenuifolia. The transcriptome database of S. tenuifolia leaves under 0, 50, 100 and 250 µM MeJA treatment was established. We generated 88,373 unigenes with an N50 length of 2678 bp, of which 50,843 (57.53%) can be annotated in at least one database. Compared with the CK (0 µM) group, 12,557 (50 µM), 15,409 (100 µM) and 13,286 (250 µM) differentially expressed genes were identified. GO and KEGG enrichment analysis revealed that JA signal transduction and monoterpenoid synthesis were the two most significant enrichment pathways. The expression levels of related DEGs involved in JA signaling and monoterpenoid synthesis were significantly up-regulated by MeJA. In addition, our phenotypic and differentially expressed gene association analysis revealed that monoterpenoid biosynthesis in S. tenuifolia was more associated with genes involved in plant trichome branching, phytohormone signaling and transcriptional regulation. CONCLUSIONS: This study confirmed that methyl jasmonate significantly promoted monoterpenoid biosynthesis in S. tenuifolia. A large number of genes responding to methyl jasmonate were associated with JA signaling and monoterpenoid biosynthesis.

Moderate white light exposure enhanced spatial memory retrieval by activating a central amygdala-involved circuit in mice.

Light exposure can profoundly affect neurological functions and behaviors. Here, we show that short-term exposure to moderate (400 lux) white light during Y-maze test promoted spatial memory retrieval and induced only mild anxiety in mice. This beneficial effect involves the activation of a circuit including neurons in the central amygdala (CeA), locus coeruleus (LC), and dentate gyrus (DG). Specifically, moderate light activated corticotropin-releasing hormone (CRH) positive (+) CeA neurons and induced the release of corticotropin-releasing factor (CRF) from their axon terminals ending in the LC. CRF then activated tyrosine hydroxylase-expressing LC neurons, which send projections to DG and release norepinephrine (NE). NE activated ß-adrenergic receptors on CaMKIIα-expressing DG neurons, ultimately promoting spatial memory retrieval. Our study thus demonstrated a specific light scheme that can promote spatial memory without excessive stress, and unraveled the underlying CeA-LC-DG circuit and associated neurochemical mechanisms.

Bright light exposure induces dynamic changes of spatial memory in nocturnal rodents.

Bright light has been reported to improve spatial memory of diurnal rodents, yet how it will influence the spatial memory of nocturnal rodents is unknown. Here, we found that dynamic changes in spatial memory and anxiety were induced at different time point after bright light treatment. Mice maintained in brighter light exhibited impaired memory in Y maze at one day after bright light exposure, but showed significantly improved spatial memory in the Y maze and Morris water maze at four weeks after bright light exposure. We also found increased anxiety one day after bright light exposure, which could be the reason of impaired memory. However, no change of anxiety was detected after four weeks. Thus, we further explore the underlying mechanism of the beneficial effects of long term bright light on spatial memory. Golgi staining indicated that the structure of dendritic spines changed, accompanied by increased expression of synaptophysin and postsynaptic density 95 in the hippocampus. Further research has found that bright light treatment leads to elevated CaMKII/CREB phosphorylation levels in the hippocampus, which are associated with synaptic function. Moreover, higher expression of brain-derived neurotrophic factor (BDNF) was followed by increased phosphorylated TrkB levels in the hippocampus, indicating that BDNF/TrkB signaling is also activated during this process. Taken together, these findings revealed that bright light exposure with different duration exert different effects on spatial memory in nocturnal rodents, and the potential molecular mechanism by which long term bright light regulates spatial memory was also demonstrated.

Genome-Wide Identification of Brassinosteroid Signaling Downstream Genes in Nine Rosaceae Species and Analyses of Their Roles in Stem Growth and Stress Response in Apple.

Brassinosteroid signaling downstream genes regulate many important agronomic traits in rice. However, information on such genes is limited in Arabidopsis and Rosaceae species. We identified these genes in Arabidopsis and nine Rosaceae species. They were, respectively, named based on chromosomal locations. Segmental duplication and whole-genome duplication under purifying selection, as determined by Ka/Ks analysis, likely contributed to Rosaceae gene expansion. Apple (Malus domestica), Arabidopsis, and rice genes were generally similar, while several Rosaceae genes differed from their rice homologs in various characteristics, such as gene length, subcellular localization, transmembrane topology, conserved domains, secondary structures, and responses to external signals. The brassinosteroid downstream genes in apple were, respectively, induced or repressed by five phytohormones. Furthermore, these apple downstream genes were differentially expressed in different apple grafting combinations ("Nagafu No. 2"/"Malling 9" and "Nagafu No. 2"/"Nagafu No. 2") and long-short shoot varieties ("Yanfu No. 6" and "Nagafu No. 2"). Responses of the MdBZR genes to diverse stress signals were examined and candidate hub genes were identified. These findings indicated that several brassinosteroid signaling downstream genes in Rosaceae functionally differed from their rice homologs, and certain apple genes may play roles in plant height and stress responses. This study provided valuable information and presented enriched biological theories on brassinosteroid signaling downstream genes in apple. Identification of such genes serve to help expand apple breeding and growth. This study provides useful information for brassinosteroid signaling downstream genes.

Relationship between perfectionism and attitudes toward doping in young athletes: the mediating role of autonomous and controlled motivation.

BACKGROUND: Recent studies suggest that autonomous and controlled motivation may mediate the relationship between perfectionism and attitudes toward doping. The purpose of this study was to investigate the association among perfectionistic strivings, perfectionistic concerns, autonomous motivation, controlled motivation, and attitudes toward doping in young athletes. The potential mediating role of autonomous and controlled motivation was examined. METHODS: Two hundred and forty-three Chinese athletes were surveyed using questionnaires. Structural equation modeling (SEM) was conducted to evaluate the potential mediating role of autonomous and controlled motivation between perfectionism and attitudes toward doping. RESULTS: The results showed that perfectionistic strivings was negatively associated with attitudes toward doping, whereas perfectionistic concerns positively predicted attitudes toward doping. Autonomous motivation was negatively associated with attitudes toward doping, whereas controlled motivation positively predicted attitudes toward doping. The mediation analyses showed that the relationship between perfectionistic strivings and attitudes toward doping was partially mediated by autonomous motivation. The relationship between perfectionistic concerns and attitudes toward doping was partially mediated by controlled motivation. CONCLUSIONS: The findings suggested that fostering perfectionistic strivings and autonomous motivation and reducing perfectionistic concerns and controlled motivation may be considered for inclusion in athletes' anti-doping education.

Executive Function Performance in Young Adults When Cycling at an Active Workstation: An fNIRS Study.

BACKGROUND: This study aimed to investigate the effects of self-paced cycling at an active workstation on executive functions and cortical activity. METHODS: In a crossover study design, 37 young adults (45.9% females) were randomly assigned to the following two task conditions: (1) performing cognitive tests during sitting, (2) performing cognitive tests while cycling at an active workstation. Executive functions were assessed by the Stroop color and word test and the task-switching paradigm. Cortical activity was monitored using a multi-channel functional near-infrared spectroscopy (fNIRS) system. RESULTS: The behavioral results showed that there were no significant differences on the Stroop interference effects (P = 0.66) between the sitting and the cycling conditions. In all probability, no differences on the global switch costs (P = 0.90) and local switch costs (P = 0.67) were observed between the sitting and the cycling conditions. For the fNIRS results, the oxygenated hemoglobin (oxy-Hb) in response to the Stroop interference in channels 5, 10, and 12 were decreased during the cycling condition (all Ps < 0.05, FDR-corrected). Conversely, the oxy-Hb associated with the global switch costs in channels 3, 29, and 31 were increased during the cycling condition (all Ps < 0.05, FDR-corrected). CONCLUSIONS: The findings indicated that behavioral performances on executive functions were not affected by cycling at an active workstation, while cognitive resources were reallocated during cycling at an active workstation.