Heavy grazing reduces soil bacterial diversity by increasing soil pH in a semi-arid steppe.

Background: In a context of long-term highly intensive grazing in grassland ecosystems, a better understanding of how quickly belowground biodiversity responds to grazing is required, especially for soil microbial diversity. Methods: In this study, we conducted a grazing experiment which included the CK (no grazing with a fenced enclosure undisturbed by livestock), light and heavy grazing treatments in a desert steppe in Inner Mongolia, China. Microbial diversity and soil chemical properties (i.e., pH value, organic carbon, inorganic nitrogen (IN, NH4+-N and NO3--N), total carbon, nitrogen, phosphorus, and available phosphorus content) both in rhizosphere and non-rhizosphere soils were analyzed to explore the responses of microbial diversity to grazing intensity and the underlying mechanisms. Results: The results showed that heavy grazing only deceased bacterial diversity in the non-rhizosphere soil, but had no any significant effects on fungal diversity regardless of rhizosphere or non-rhizosphere soils. Bacterial diversity in the rhizosphere soil was higher than that of non-rhizosphere soil only in the heavy grazing treatment. Also, heavy grazing significantly increased soil pH value but deceased NH4+-N and available phosphorus in the non-rhizosphere soil. Spearman correlation analysis showed that soil pH value was significantly negatively correlated with the bacterial diversity in the non-rhizosphere soil. Combined, our results suggest that heavy grazing decreased soil bacterial diversity in the non-rhizosphere soil by increasing soil pH value, which may be due to the accumulation of dung and urine from livestock. Our results highlight that soil pH value may be the main factor driving soil microbial diversity in grazing ecosystems, and these results can provide scientific basis for grassland management and ecological restoration in arid and semi-arid area.

Genome-wide characterization of the bHLH gene family in Gynostemma pentaphyllum reveals its potential role in the regulation of gypenoside biosynthesis.

BACKGROUND: Gynostemma pentaphyllum, an ancient Chinese herbal medicine, serves as a natural source of gypenosides with significant medicinal properties. Basic helix-loop-helix (bHLH) transcription factors play pivotal roles in numerous biological processes, especially in the regulation of secondary metabolism in plants. However, the characteristics and functions of the bHLH genes in G. pentaphyllum remain unexplored, and their regulatory role in gypenoside biosynthesis remains poorly elucidated. RESULTS: This study identified a total of 111 bHLH members in G. pentaphyllum (GpbHLHs), categorizing them into 26 subgroups based on shared conserved motif compositions and gene structures. Collinearity analysis illustrated that segmental duplications predominately lead to the evolution of GpbHLHs, with most duplicated GpbHLH gene pairs undergoing purifying selection. Among the nine gypenoside-related GpbHLH genes, two GpbHLHs (GpbHLH15 and GpbHLH58) were selected for further investigation based on co-expression analysis and functional prediction. The expression of these two selected GpbHLHs was dramatically induced by methyl jasmonate, and their nuclear localization was confirmed. Furthermore, yeast one-hybrid and dual-luciferase assays demonstrated that GpbHLH15 and GpbHLH58 could bind to the promoters of the gypenoside biosynthesis pathway genes, such as GpFPS1, GpSS1, and GpOSC1, and activate their promoter activity to varying degrees. CONCLUSIONS: In conclusion, our findings provide a detailed analysis of the bHLH family and valuable insights into the potential use of GpbHLHs to enhance the accumulation of gypenosides in G. pentaphyllum.

[Identification of terpene synthase gene family in Gynostemma pentaphyllum and expression pattern analysis under abiotic stresses].

The present study aimed to investigate the composition of the terpene synthase(TPS) gene family in Gynostemma pentaphyllum and its role in abiotic stresses. The G. pentaphyllum TPS gene family was identified and analyzed at the genome-wide level using bioinformatics analysis, and the expression patterns of these family members were analyzed in different tissues of G. pentaphyllum as well as under various abiotic stresses. The results showed that there were 24 TPS gene family members in G. pentaphyllum with protein lengths ranging from 294 to 842 aa. All of them were localized in the cytoplasm or chloroplasts and unevenly distributed on the 11 chromosomes of G. pentaphyllum. The results of the phylogenetic tree showed that the G. pentaphyllum TPS gene family members could be divided into five subfamilies. As revealed by the analysis of promoter cis-acting elements, TPS gene family members in G. pentaphyllum were predicted to respond to a variety of abiotic stresses such as salt, low temperature, and dark stress. The analysis of gene expression patterns in different tissues of G. pentaphyllum revealed that nine TPS genes were tissue-specific in expression. The qPCR results showed that GpTPS16, GpTPS17, and GpTPS21 responded to a variety of abiotic stresses. This study is expected to provide references in guiding the further exploration of the biological functions of G. pentaphyllum TPS genes under abiotic stresses.

Demonstration of a bi-directionally tunable arrayed waveguide grating with ultra-low thermal power using S-shaped architecture and parallel-circuit configuration.

A thermally bi-directionally tunable arrayed waveguide grating (TBDTAWG) is proposed and demonstrated on a silicon-on-insulator (SOI) platform. The device is composed of passive and active designs for realizations of an AWG and fine tuning of its filtering responses. Given that the required length difference between adjacent arrayed waveguides for the SOI platform is considerably short (∼3-5 µm) due to a high index contrast, an S-shaped architecture with a larger footprint instead of a rectangular one is employed in the AWG. Bi-directionally tunable functions, i.e., both red- and blue-shift tunable functions, can be achieved by using two triangular thermal-tuning regions with complementary phase distributions in the S-shaped architecture despite using only materials with positive thermo-optic coefficients, i.e., Si and SiO2. Measurement results illustrate that both red- or blue-shifted spectra can be achieved and a linear bi-directional shift-to-power ratio of ±30.5 nm/W as well as a wide tuning range of 8 nm can be obtained under an electrical voltage range of 0-2.5 V, showing an agreement between the measurement results and two-dimensional simulation results. This also shows the potential of the proposed TBDTAWG for automatically stabilizing the spectral responses of AWG-based (de)multiplexers for coarse or dense wavelength division multiplexing communication systems by using a feedback control circuit.

Effects of animated pedagogical agent-guided loving-kindness meditation on flight attendants' spirituality, mindfulness, subjective wellbeing, and social presence.

Loving-kindness meditation (LKM) was first practiced by Buddhists and then developed by clinical psychologist. Previous studies on LKM have mainly focused on the impact of real person-guided meditation on depression, anxiety, and other negative psychology. During the COVID-19 pandemic, this study explored the effect and mechanism of media-guided LKM on the improvement of social presence, mindfulness, spirituality, and subjective wellbeing (SWB). From the viewpoint of positive psychology, this study compared the different media effects of animated pedagogical agent (APA)-guided LKM and audio-guided LKM. A total of 82 flight attendants were recruited from airlines; then, they were randomly assigned to two groups: APA group (41 participants) and audio group (41 participants), which both underwent an 8-week LKM training intervention. The aforementioned four main variables were measured pre and post the meditation experiment. The results indicated that both APA-guided meditation and audio-guided meditation significantly improved subjects' spirituality and SWB. Compared with audio-guided meditation, APA-guided meditation significantly improved the subjects' spirituality, SWB, and social presence. Audio-guided meditation has no significant effect on social presence. This study highlights APA-guided meditation has a positive effect on spirituality, SWB, and social presence, which may provide individuals with a simple and easy method to improve their mental health.

The effect of loving-kindness meditation on employees' mindfulness, affect, altruism and knowledge hiding.

BACKGROUND: This study investigated the effects of the loving-kindness meditation (LKM) on employees' mindfulness, affect, altruism and knowledge hiding. METHODS: In total, 100 employees were recruited from a knowledge-based enterprise in China and randomly divided into the LKM training group (n = 50) and the control group (n = 50). The LKM training group underwent LKM training for 8 weeks, while the control group did not. Seven main variables (mindfulness, altruism positive affect, negative affect, playing dumb, rationalized hiding, and evasive hiding) were measured both before (pre-test) and after (post-test) the LKM training intervention. RESULTS: The LKM intervention significantly increased participants' altruism, and significantly reduced negative affect, playing dumb and evasive hiding, but did not significantly improve mindfulness, positive affect, and rationalized hiding. CONCLUSIONS: LKM significantly improved employees' altruism, and significantly reduce their negative affect, but did not significantly improve their mindfulness and positive affect. For knowledge hiding, LKM significantly reduced playing dumb and evasive hiding, but had no significant effect on rationalized hiding. These results further elucidate the psychological effects of LKM and suggest the possibility of reducing knowledge hiding in the workplace. TRIAL REGISTRATION: ChiCTR2200057460. Registered in Chinese Clinical Trial Registry (ChiCTR), 13 March 2022-Retrospectively registered.

The Effect of Animation-Guided Mindfulness Meditation on the Promotion of Creativity, Flow and Affect.

Creativity is so important for social and technological development that people are eager to find an easy way to enhance it. Previous studies have shown that mindfulness has significant effects on positive affect (PA), working memory capacity, cognitive flexibility and many other aspects, which are the key to promoting creativity. However, there are few studies on the relationship between mindfulness and creativity. The mechanism between mindfulness and creativity is still uncertain. Meditation is an important method of mindfulness training, but for most people who do not have the basic training, it's difficult to master how to get into a state of mindfulness. Animation has been shown by many studies to help improve cognition and is often used as a guiding tool. Using animation as the guiding carrier of meditation is more convenient and easier to accept. Therefore, this study adopted the intervention method of animation-guided meditation, aiming to explore: (1) the effect of animation-guided meditation on enhancing creativity; (2) the role of flow and emotion in the influence of mindfulness on creativity. We advertised recruitment through the internal network of a creative industrial park, and the final 95 eligible participants were divided into two groups: animation (n = 48) and audio (n = 47) guided meditation. The animation group was given an animated meditation intervention, and the audio group was given an audio meditation intervention, both interventions were performed 3 times a week and last for 8 weeks. Results: (1) Animation-guided meditation significantly increased participants' mindfulness and creativity levels; Significantly reduced their cognitive load compared to audio-guided meditation. (2) Mindfulness has a significant direct effect on creativity, and significant indirect effects on creativity; Flow and PA act as the mediating variable. Conclusion: (1) Mindfulness, flow, and PA all helped to improve the subjects' work creativity. In addition to the direct positive impact of mindfulness on creativity, mindfulness can also have an indirect positive impact on creativity through flow and PA. (2) Compared with audio, animation can significantly reduce cognitive load and help improve users' cognitive ability, which is more suitable for the guidance materials of mindfulness meditation to enhance the effect of meditation.

Focused-Attention Meditation Improves Flow, Communication Skills, and Safety Attitudes of Surgeons.

OBJECTIVE: Patient safety is a worldwide problem and a focus of academic research. Human factors and ergonomics (HFE) is an approach to improving healthcare work systems and processes. From the perspective of the cognitive ergonomics of HFE, the aim of this study is to improve the flow level, communication skills, and safety attitudes of surgeons through focused-attention meditation (FAM) training, thus helping to reduce adverse clinical events. METHODS: In total, 140 surgeons were recruited from three hospitals in China and randomly divided into two groups (FAM group and control group). The FAM group received 8 weeks of FAM training, while the control group was on the waiting list and did not receive any interventions. Three scales (WOLF, LCSAS, and SAQ-C) were used to measure the data of three variables (flow, communication skills, and safety attitude), respectively, at two times, before and after the intervention (pre-test and post-test). The incidence of adverse events during the intervention was also collected for both groups. RESULTS: The ANOVA results showed that all three variables had a significant main effect of time and significant interactions between time and group. The independent-sample T-test results showed that the incidence of adverse events during the intervention was significantly lower in the FAM group than in the control group. CONCLUSIONS: The intervention of FAM could significantly improve surgeons' flow levels, communication skills, and safety attitudes, potentially helping to reduce adverse clinical events.

Effects of Mindfulness Meditation on Doctors' Mindfulness, Patient Safety Culture, Patient Safety Competency and Adverse Event.

OBJECTIVE: This study investigated the effects of mindfulness meditation on doctors' mindfulness, patient safety culture, patient safety competency, and adverse events. METHODS: We recruited 91 doctors from a hospital in China and randomized them to mindfulness meditation group (n = 46) and a waiting control group (n = 45). The mindfulness meditation group underwent an 8-week mindfulness meditation intervention, while the control group underwent no intervention. We measured four main variables (mindfulness, patient safety culture, patient safety competency, and adverse event) before and after the mindfulness meditation intervention. RESULTS: In the experimental group, mindfulness, patient safety culture and patient safety competency were significantly higher compared with those of the control group. In the control group, there were no significant differences in any of the three variables between the pre-test and post-test. Adverse events in the experimental group were significantly lower than in the control group. CONCLUSIONS: The intervention of mindfulness meditation significantly improved the level of mindfulness, patient safety culture and patient safety competency. During the mindfulness meditation intervention, the rate of adverse events in the meditation group was also significantly lower than in the control group. As a simple and effective intervention, mindfulness meditation plays a positive role in improving patient safety and has certain promotional value.

The complete chloroplast genome sequence of the medicinal plant Abrus pulchellus subsp. cantoniensis: genome structure, comparative and phylogenetic relationship analysis.

Abrus pulchellus subsp. cantoniensis, an endemic medicinal plant in southern China, is clinically used to treat jaundice hepatitis, cholecystitis, stomachache and breast carbuncle. Here, we assembled and analyzed the first complete chloroplast (cp) genome of A. pulchellus subsp. cantoniensis. The A. pulchellus subsp. cantoniensis cp genome size is 156,497 bp with 36.5% GC content. The cp genome encodes 130 genes, including 77 protein-coding genes, 30 tRNA genes and four rRNA genes, of which 19 genes are duplicated in the inverted repeats (IR) regions. A total of 30 codons exhibited codon usage bias with A/U-ending. Moreover, 53 putative RNA editing sites were predicted in 20 genes, all of which were cytidine to thymine transitions. Repeat sequence analysis identified 45 repeat structures and 125 simple-sequence repeats (SSRs) in A. pulchellus subsp. cantoniensis cp genome. In addition, 19 mononucleotides (located in atpB, trnV-UAC, ycf3, atpF, rps16, rps18, clpP, rpl16, trnG-UCC and ndhA) and three compound SSRs (located in ndhA, atpB and rpl16) showed species specificity between A. pulchellus subsp. cantoniensis and Abrus precatorius, which might be informative sources for developing molecular markers for species identification. Furthermore, phylogenetic analysis inferred that A. pulchellus subsp. cantoniensis was closely related to A. precatorius, and the genus Abrus formed a subclade with Canavalia in the Millettioid/Phaseoloid clade. These data provide a valuable resource to facilitate the evolutionary relationship and species identification of this species.

Chromosomal-level genome and multi-omics dataset of Pueraria lobata var. thomsonii provide new insights into legume family and the isoflavone and puerarin biosynthesis pathways.

Pueraria lobata var. thomsonii (hereinafter abbreviated as Podalirius thomsonii), a member of legumes, is one of the important traditional Chinese herbal medicines, and its puerarin extraction is widely used in health and pharmaceutical industry. Here, we assembled a high-quality genome of P. thomsonii using long-read single-molecule sequencing and Hi-C technologies. The genome assembly is approximately 1.37 Gb in size and consists of 5145 contigs with a contig N50 of 593.70 Kb, further clustered into 11 pseudochromosomes. The genome structural annotation resulted in about 869.33 Mb (about 62.70% of the genome) repeat regions and 45 270 protein-coding genes. Genome evolution analysis revealed that P. thomsonii is most closely related to soybean and underwent two ancient whole-genome duplication events, one was in the common ancestor shared by legume species, the other occurred independently at around 7.2 million years ago after its specification. A total of 2373 gene families were found unique in P. thomsonii comparing to five other legume species. Genes and metabolites related to puerarin content in tuberous tissues were characterized. A total of 572 genes upregulated in the puerarin biosynthesis pathway were identified, and 235 candidate genes were further enriched by omics data. Furthermore, we identified 6 8-C-glucosyltransferase (8-C-GT) candidate genes significantly involved in puerarin metabolism. Our study filled in a key genomic gap in legume family, and provided valuable multi-omic resources for the genetic improvement of P. thomsonii.

Identification of Nutritional Ingredients and Medicinal Components of Pueraria lobata and Its Varieties Using UPLC-MS/MS-Based Metabolomics.

Pueraria lobata and its variety P. lobata var. thomsonii are both traditional Chinese medicines that have high nutritional and medical value; whereas another variety, P. lobata var. montana has low nutritional and medicinal value and can cause ecological disasters. The material basis of different nutritional and medicinal values, which are caused by metabolite differences among these varieties, remains to be further clarified. Here, we performed ultra performance liquid chromatography-tandem mass spectrometry based widely targeted metabolome analysis on Pueraria lobata, P. lobata var. thomsonii, and P. lobata var. montana. Among them, a total of 614 metabolites were identified, and distinguished from each other using orthogonal partial least squares discriminant analysis. Our results suggest that the nutritional differences between P. lobata and its varieties can be explained by variations in the abundance of amino acids, nucleotides, saccharides, and lipids; differences in flavonoids, isoflavones, phenolic acids, organic acids, and coumarins contents caused the differences in the medicinal quality of P. lobata and its varieties. Additionally, the key metabolites responsible for the classification of the three Pueraria varieties were identified. This study provides new insights into the underlying metabolic causes of nutritional and medicinal variation in P. lobata and its varieties.

Chromosome-level genome assembly of Gynostemma pentaphyllum provides insights into gypenoside biosynthesis.

Gynostemma pentaphyllum (Thunb.) Makino is an economically valuable medicinal plant belonging to the Cucurbitaceae family that produces the bioactive compound gypenoside. Despite several transcriptomes having been generated for G. pentaphyllum, a reference genome is still unavailable, which has limited the understanding of the gypenoside biosynthesis and regulatory mechanism. Here, we report a high-quality G. pentaphyllum genome with a total length of 582 Mb comprising 1,232 contigs and a scaffold N50 of 50.78 Mb. The G. pentaphyllum genome comprised 59.14% repetitive sequences and 25,285 protein-coding genes. Comparative genome analysis revealed that G. pentaphyllum was related to Siraitia grosvenorii, with an estimated divergence time dating to the Paleogene (∼48 million years ago). By combining transcriptome data from seven tissues, we reconstructed the gypenoside biosynthetic pathway and potential regulatory network using tissue-specific gene co-expression network analysis. Four UDP-glucuronosyltransferases (UGTs), belonging to the UGT85 subfamily and forming a gene cluster, were involved in catalyzing glycosylation in leaf-specific gypenoside biosynthesis. Furthermore, candidate biosynthetic genes and transcription factors involved in the gypenoside regulatory network were identified. The genetic information obtained in this study provides insights into gypenoside biosynthesis and lays the foundation for further exploration of the gypenoside regulatory mechanism.

Identification of Isoflavonoid Biosynthesis-Related R2R3-MYB Transcription Factors in Callerya speciosa (Champ. ex Benth.) Schot Using Transcriptome-Based Gene Coexpression Analysis.

The R2R3-MYB family is one of the largest plant transcription factor (TF) families playing vital roles in defense, plant growth, and secondary metabolism biosynthesis. Although this gene family has been studied in many species, isoflavonoid biosynthesis-related R2R3-MYB TFs in Callerya speciosa (Champ. ex Benth.) Schot, a traditional Chinese medicinal herb, are poorly understood. Here, a total of 101 R2R3-MYB TFs were identified from C. speciosa transcriptome dataset. 25 clades divided into five functional groups were clustered based on the sequence similarity and phylogenetic tree. Conserved motifs and domain distribution, expression patterns, and coexpression networks were also employed to identify the potential R2R3-MYB TFs in the regulation of isoflavonoid biosynthesis. In silico evaluation showed that the deduced R2R3-CsMYB proteins contain highly conserved R2R3 repeat domain at the N-terminal region, that is the signature motif of R2R3-type MYB TFs. Eight potential TFs (CsMYB17, CsMYB36, CsMYB41, CsMYB44, CsMYB45, CsMYB46, CsMYB72, and CsMYB81) had high degrees of coexpression with four key isoflavonoid biosynthetic genes (CsIFS, CsCHS7, CsHID-1, and CsCHI3), in which CsMYB36 as a potential regulator possessed the highest degree. HPLC analysis showed that formononetin and maackiain contents were significantly increased during the development of tuberous roots, which might be controlled by both related R2R3-CsMYBs and structural genes involved in the isoflavonoid biosynthesis pathway. The transcriptome data were further validated by reverse transcription real-time PCR (RT-qPCR) analysis, and similar expression profiles between TFs and key structural genes were identified. This study was the first step toward the understanding of the R2R3-MYB TFs regulating isoflavonoid biosynthesis in C. speciosa. The results will provide information for further functional analysis and quality improvement through genetic manipulation of these potential R2R3-CsMYB genes in C. speciosa.

Effects of Loving-Kindness Meditation on Doctors' Mindfulness, Empathy, and Communication Skills.

BACKGROUND: In the context of increasing doctor-patient tensions in China, the objective of this study was to explore and examine the effects of loving-kindness meditation (LKM) on doctors' mindfulness, empathy, and communication skills. METHODS: A total of 106 doctors were recruited from a hospital in China, and randomly divided into an LKM training group (n = 53) and waiting control group (n = 53). The LKM training group received 8 weeks of LKM training intervention, whereas the control group received no intervention. Three major variables (mindfulness, empathy, and communication skills) were measured before (pre-test) and after (post-test) the LKM training intervention. RESULTS: The empathy and communication skills of the LKM group were significantly improved compared with those of the control group, but the level of mindfulness did not significantly change. CONCLUSIONS: The results suggested that LKM may contribute to improving physicians' empathy and communication skills. However, the mechanisms that underlie the effects of the LKM on mindfulness, empathy, and communication skills and other psychological constructs needs further elucidation.

Hormonal and transcriptional analyses provides new insights into the molecular mechanisms underlying root thickening and isoflavonoid biosynthesis in Callerya speciosa (Champ. ex Benth.) Schot.

Callerya speciosa (Champ. ex Benth.) Schot is a traditional Chinese medicine characterized by tuberous roots as the main organ of isoflavonoid accumulation. Root thickening and isoflavonoid accumulation are two major factors for yield and quality of C. speciosa. However, the underlying mechanisms of root thickening and isoflavonoid biosynthesis have not yet been elucidated. Here, integrated morphological, hormonal and transcriptomic analyses of C. speciosa tuberous roots at four different ages (6, 12, 18, 30 months after germination) were performed. The growth cycle of C. speciosa could be divided into three stages: initiation, rapid-thickening and stable-thickening stage, which cued by the activity of vascular cambia. Endogenous changes in phytohormones were associated with developmental changes during root thickening. Jasmonic acid might be linked to the initial development of tuberous roots. Abscisic acid seemed to be essential for tuber maturation, whereas IAA, cis-zeatin and gibberellin 3 were considered essential for rapid thickening of tuberous roots. A total of 4337 differentially expressed genes (DEGs) were identified during root thickening, including 15 DEGs participated in isoflavonoid biosynthesis, and 153 DEGs involved in starch/sucrose metabolism, hormonal signaling, transcriptional regulation and cell wall metabolism. A hypothetical model of genetic regulation associated with root thickening and isoflavonoid biosynthesis in C. speciosa is proposed, which will help in understanding the underlying mechanisms of tuberous root formation and isoflavonoid biosynthesis.

Genome-Wide Identification of R2R3-MYB Transcription Factors: Discovery of a "Dual-Function" Regulator of Gypenoside and Flavonol Biosynthesis in Gynostemma pentaphyllum.

The R2R3-MYB gene family participates in several plant physiological processes, especially the regulation of the biosynthesis of secondary metabolites. However, little is known about the functions of R2R3-MYB genes in Gynostemma pentaphyllum (G. pentaphyllum), a traditional Chinese medicinal herb that is an excellent source of gypenosides (a class of triterpenoid saponins) and flavonoids. In this study, a systematic genome-wide analysis of the R2R3-MYB gene family was performed using the recently sequenced G. pentaphyllum genome. In total, 87 R2R3-GpMYB genes were identified and subsequently divided into 32 subgroups based on phylogenetic analysis. The analysis was based on conserved exon-intron structures and motif compositions within the same subgroup. Collinearity analysis demonstrated that segmental duplication events were majorly responsible for the expansion of the R2R3-GpMYB gene family, and Ka/Ks analysis indicated that the majority of the duplicated R2R3-GpMYB genes underwent purifying selection. A combination of transcriptome analysis and quantitative reverse transcriptase-PCR (qRT-PCR) confirmed that Gynostemma pentaphyllum myeloblastosis 81 (GpMYB81) along with genes encoding gypenoside and flavonol biosynthetic enzymes exhibited similar expression patterns in different tissues and responses to methyl jasmonate (MeJA). Moreover, GpMYB81 could bind to the promoters of Gynostemma pentaphyllum farnesyl pyrophosphate synthase 1 (GpFPS1) and Gynostemma pentaphyllum chalcone synthase (GpCHS), the key structural genes of gypenoside and flavonol biosynthesis, respectively, and activate their expression. Altogether, this study highlights a novel transcriptional regulatory mechanism that suggests that GpMYB81 acts as a "dual-function" regulator of gypenoside and flavonol biosynthesis in G. pentaphyllum.

Soil extracellular enzyme activities and the abundance of nitrogen-cycling functional genes responded more to N addition than P addition in an Inner Mongolian meadow steppe.

Nitrogen (N) and phosphorus (P) availability in soils commonly limit belowground biological processes in terrestrial ecosystems. Soil extracellular enzyme activities (EEAs) and microbial functional groups play critical roles in soil biological processes and nutrient cycling, yet their response to nutrient addition are poorly understood. To address this issue, we applied six fertilization treatments composed of combinations of N (0, 1.55, 13.95 g N m-2 yr-1) and P (0, 5.24 g P m-2 yr-1) for two years in a meadow steppe of Inner Mongolia. Soils were collected from each plot in July and August and analyzed for abundances of N-cycling genes and EEAs, and their relationships with treatments. The addition of N significantly increased C-acquisition enzyme activity and enzyme C:N and C:P ratios. Enzymatic stoichiometry indicated that N addition alleviated microbial demand for N, while it increased microbial C limitation. Microbial C and N limitation were significantly correlated with NH4+-N in July, yet they were correlated with soil water content (SWC) in August. The abundance of amoA significantly increased with N addition and was positively related to mineral-N accumulation. The abundance of denitrifier genes and gaseous N loss potential were accelerated by N addition in July, while a neutral effect was observed in August. Nitrate leaching potential was significantly increased by N addition, yet it declined with P addition in July. P addition also suppressed amoA abundance of ammonia oxidizing bacteria. Partial least squares path modelling indicated that N addition positively affected microbial-C limitation, soil N-loss potential and negatively affected microbial-N limitation. P addition negatively affected soil N-loss potential. Ultimately, this study highlights the importance of soil N availability in regulating microbial metabolism and soil N-loss potential, and enhances our understanding of the mechanisms responsible for variation in microbial nutrient cycling in meadow steppe soils.

Transcriptome-wide analysis of the AP2/ERF transcription factor gene family involved in the regulation of gypenoside biosynthesis in Gynostemma pentaphyllum.

Gynostemma pentaphyllum is a traditional Chinese medicinal herb, serving as natural source of gypenosides (triterpene saponins). The APETALA2/ethylene response factor (AP2/ERF) transcription factors, playing essential regulation roles in plant biotic and abiotic stress responses and secondary metabolism biosynthesis. However, the regulation roles of AP2/ERF transcription factors in gypenosides biosynthesis in G. pentaphyllum remains little understood. In the present study, 125 AP2/ERF genes were identified from G. pentaphyllum transcriptome datasets. Phylogenetic, conserved motifs and expression pattern were employed to comprehensively analyze the 125 GpAP2/ERF genes. Based on the sequence similarity and phylogeny tree, the 125 GpAP2/ERF genes can be classified into 10 groups. Moreover, the distribution of conserved motifs among GpAP2/ERF proteins in phylogenetic trees was consistent with previous studies, thus supporting the classification. Expression profiling indicated that the 125 GpAP2/ERF genes exhibited distinct tissue-specific expression patterns. As confirmed by qRT-PCR, the four candidate GpAP2/ERF genes and gypenoside biosynthetic genes were highly expressed in leaves and/or flowers, and show similar expression patterns in response to MeJA. Base on the expression patterns and phylogenetic relationships, two GpAP2/ERF genes were considered as potential regulatory genes for gypenoside biosynthesis. Our study enhances understanding roles of GpAP2/ERF genes in regulation of gypenosides biosynthesis.

Spatial patterns in soil physicochemical and microbiological properties in a grassland adjacent to a newly built lake.

Soil water content (SWC) is an important determinant for nutrient cycling and microorganism activity in the grassland ecosystem. Lakes have a positive effect on the water supply of the neighboring ecosystem. However, information evaluating whether newly built lakes improve the physiochemical properties and microorganism activity of adjacent grassland soil is rare. A 15-hectare artificial lake with a 2 m depth was built on grazed grassland to determine whether the change of soil physiochemical properties and microorganism activity of the adjacent grassland depended on the distance from the lake. SWC and total nitrogen (TN) were greater within 150 m of the lake than at distances over 150 m from the lake. The total organic carbon (TOC) increased first at 100-150 m from the lake and then decreased. The soil microbial biomass and the bacterial and fungal contents increased with increasing years after the construction of the lake. Gram-negative bacteria and methanotrophic bacteria were greater within a 30 m distance of the lake. Over 60 m away from the lake, Actinobacteria, gram-positive bacteria, and anaerobic bacteria showed higher abundances. In the area near the lake (<250 m distance), microorganisms were strongly correlated with SWC, EC, TN, and TOC and greatly correlated with the changes of total phosphorous (TP) and pH when the distance from the lake was over 250 m. The results indicated that the newly built lake could be a driving factor for improving the physiochemical properties and microorganism activity of adjacent grassland soil within a certain range.