Southern Regions Of China Research Articles

Agricultural socialized services to stimulate the green production behavior of smallholder farmers: the case of fertilization of rice production in south China

Introduction: This study investigates the impact of Agricultural Socialized Services (ASSs) on the green production behavior (GPB) of smallholder farmers in the main rice production region of southern China. The research aims to address the gap in understanding the relationship between ASSs and the adoption of sustainable agricultural practices by smallholder farmers.Methodology: Data was collected from 741 smallholder farmers in Hunan, Jiangxi, and Zhejiang provinces using a structured questionnaire. A probit model was employed to examine the relationship between ASSs and smallholder farmers’ GPB.Results and Discussion: The study revealed that ASSs have a significant and positive impact on smallholder farmers’ GPB. Farmers who received ASSs tended to adopt more sustainable agricultural practices such as using organic fertilizer and soil-tested formula fertilizer. The findings of this study have important implications for policymakers. The results suggest that policymakers should prioritize the development of services to agricultural producers and strengthen Agricultural Service Systems. This can be achieved through optimizing the public administration service system, establishing joint service organizations, and creating a good financial and legal service environment. By doing so, policymakers can promote the adoption of sustainable agricultural practices and the overall development of the agricultural sector.

Divergent soil health responses to long-term inorganic and organic fertilization management on subtropical upland red soil in China

To optimize soil health, land use, and soil management decisions need to be guided by an understanding of the underlying soil health. Although widely used fertilizers guarantee crop production, they ultimately damage agricultural soil environmental quality and threaten the overall food chain safety. Thus, an integrative assessment considering both environmental safety and soil fertility is required for the sustainable development of long-term fertilization systems. In this study, we conducted a comprehensive assessment of soil health using 20 soil physical, chemical, and biological indicators and assessed them according to four heavy metals—copper, zinc, cadmium, and lead. This experiment was conducted in an area where there is an ongoing, 23-year-long fertilization experiment in a typical red soil region of southern China, including four treatments of common inorganic chemical fertilizer (CF), CF mixed with micronutrients (CF + T), CF mixed with pig manure (PM), and PM mixed with micronutrients (PM + T). To assess the soil fertility quality, we selected a minimum data set consisting of soil water-stable aggregates mean weight diameter, available phosphorus, total nitrogen, microbial biomass carbon, and dehydrogenase activity. The results revealed that soil fertility quality followed the order of PM + T ≈ PM > CF + T > CF. We also used a modified potential ecological risk index to assess the soil environmental quality. This approach considered the acid-soluble and exchangeable fraction of heavy metals as the bioavailability component. Both PM and PM + T treated soils were significantly contaminated by heavy metals, with particularly large amounts of Cd contamination. The soil health index escalated from CF, CF + T, PM to PM + T, which indicated that the use of pig manure allowed for more fertile soil relative to standard chemical fertilization. Moreover, applying additional micronutrients also had a significant influence on soil fertility. Therefore, our study revealed that long-term fertilization using organic pig manure was beneficial to overall soil fertility; however, these benefits were coupled with significant limitations regarding heavy metal contamination. Collectively, this study provides a better supporting method for soil health management and long-term fertilization strategies.

Climate-vegetation-erosion interactions revealed by the sediments of Huguangyan Maar Lake, southern China

Soil erosion is a serious environmental problem in the red soil region of southern China, yet little is known about the factors responsible and their specific effects on long-term soil erosion dynamics in this region. We addressed this issue via a study of the sediments of Huguangyan Maar Lake (HML), a crater lake in southern China. Our results confirm that the sediments in HML are mainly derived from the erosional input of weathering products of wall rocks, via catchment runoff. Having established the provenance of the HML sediments, the sediment accumulation rate, mass accumulation rate, and geochemical element fluxes were used to reconstruct soil erosion processes in the HML catchment over the past ∼1400 years. The potential drivers of soil erosion were explored, and regional comparisons were made to evaluate the representativeness of this study. The results show that: 1) Higher precipitation before ∼830 CE, coupled with a lower level of human activity, promoted increased vegetation coverage which reduced the rate of soil erosion. 2) Lower precipitation during 830 CE–1390 CE reduced the rate of soil loss. 3) Abundant precipitation was the main cause of the more intense soil erosion during 1390 CE–1878 CE, which may have been exacerbated by the reduced vegetation cover caused by intensive human activity. 4) During 1878 CE–2019 CE, the vegetation cover gradually recovered under the combined effects of vegetation restoration and higher precipitation, which reduced the rate of soil erosion within the HML catchment. Compared to the Chinese Loess Plateau, the erosion level in the HML catchment was relatively low during the period of intensive human activities. Overall, our results contribute to an improving understanding of the driving mechanisms of soil erosion, and they provide a guide for soil conservation measures in southern China.

Clean and low-carbon heating in the building sector of China: 10-Year development review and policy implications

Space heating in China relies heavily on fossil fuels that cause heavy air pollution and greenhouse gas emissions. The clean heating policy began in 2013 to improve air quality and is now expanding to clean and low-carbon heating (CLCH) for the 2030 carbon dioxide peaking targets. However, few studies have focused on the transformation of China's heating sector over the past decade. The heating areas in China are categorized into urban areas in Northern China, town areas in Northern China, rural areas in Northern China, and regions in Southern China. Six types of CLCH technologies with the highest potential and prospects were reviewed and summarized. In northern urban and town areas, waste heat utilization could help achieve zero-carbon district heating. However, energy-efficient and affordable distributed (household) heating technologies should be promoted in rural and southern areas. In addition, the energy-efficient retrofit of buildings is crucial for reducing heating energy demand and should be given priority. This review provides an overview of CLCH development in China and can be used as a reference for other countries to develop heating strategies.

Mapping Insect-Proof Screened Citrus Orchards Using Sentinel-2 MSl Time-Series Images

Citrus is a crucial agricultural commodity of the hilly subtropical regions of southern China. Attempts in recent years to combat the destructive disease Huanglongbing (HLB) have led to citrus orchards being covered with insect-proof screens (IPS). Understanding which citrus orchards are covered by IPS is crucial for regional water and soil conservation, as well as control of plastic pollution. However, monitoring of orchards is complicated by IPS spectral interference in remotely sensed image classification. Here, an optimal feature combination scheme is developed and tested for mapping citrus orchards that use IPS. Seasonal Sentinel-2 images from 2021 were used to define indices for vegetation, plastic mulch, red edge, and texture. These were combined with topographic and land surface temperature using random forest classification to determine optimal feature discrimination combinations for orchards in Xunwu County, Jiangxi Province. Results show: (1) significantly higher visible light reflectance from IPS orchards ensures spectral discrimination between IPS covered and uncovered orchards. (2) After feature optimization, the seasonal spectral band has the highest accuracy (86%) in single feature classification. The addition of conventional indices and topographic-temperature features improves classification to 92%. (3) Xunwu County had 460 km2 of citrus orchard cover in 2021, with 88 km2 (19%) of that total being covered with IPS. Our method effectively and accurately maps citrus orchards with or without IPS coverage at 10 m resolution. The effective monitoring of large-scale IPS in other regions can now support the development of local and regional sustainable agricultural policies.

Antagonistic transcriptome profile reveals potential mechanisms of action on Xanthomonas oryzae pv. oryzicola by the cell-free supernatants of Bacillus velezensis 504, a versatile plant probiotic bacterium.

Bacterial leaf streak (BLS) of rice is a severe disease caused by the bacterial pathogen Xanthomonas oryzae pv. oryzicola (Xoc) that has gradually become the fourth major disease on rice in some rice-growing regions in southern China. Previously, we isolated a Bacillus velezensis strain 504 that exhibited apparent antagonistic activity against the Xoc wild-type strain RS105, and found that B. velezensis 504 was a potential biocontrol agent for BLS. However, the underlying mechanisms of antagonism and biocontrol are not completely understood. Here we mine the genomic data of B. velezensis 504, and the comparative transcriptomic data of Xoc RS105 treated by the cell-free supernatants (CFSs) of B. velezensis 504 to define differentially expressed genes (DEGs). We show that B. velezensis 504 shares over 89% conserved genes with FZB42 and SQR9, two representative model strains of B. velezensis, but 504 is more closely related to FZB42 than SQR9, as well as B. velezensis 504 possesses the secondary metabolite gene clusters encoding the essential anti-Xoc agents difficidin and bacilysin. We conclude that approximately 77% of Xoc RS105 coding sequences are differentially expressed by the CFSs of B. velezensis 504, which significantly downregulates genes involved in signal transduction, oxidative phosphorylation, transmembrane transport, cell motility, cell division, DNA translation, and five physiological metabolisms, as well as depresses an additional set of virulence-associated genes encoding the type III secretion, type II secretion system, type VI secretion system, type IV pilus, lipopolysaccharides and exopolysaccharides. We also show that B. velezensis 504 is a potential biocontrol agent for bacterial blight of rice exhibiting relative control efficiencies over 70% on two susceptible cultivars, and can efficiently antagonize against some important plant pathogenic fungi including Colletotrichum siamense and C. australisinense that are thought to be the two dominant pathogenic species causing leaf anthracnose of rubber tree in Hainan province of China. B. velezensis 504 also harbors some characteristics of plant growth-promoting rhizobacterium such as secreting protease and siderophore, and stimulating plant growth. This study reveals the potential biocontrol mechanisms of B. velezensis against BLS, and also suggests that B. velezensis 504 is a versatile plant probiotic bacterium.

A chromosome-level genome assembly of Hong Kong catfish (Clarias fuscus) uncovers a sex-determining region

BackgroundHong Kong catfish (Clarias fuscus) is an ecologically and economically important species that is widely distributed in freshwater regions of southern China. Hong Kong catfish has significant sexual growth dimorphism. The genome assembly of the Hong Kong catfish would facilitate study of the sex determination and evolution mechanism of the species.ResultsThe first high-quality chromosome-level genome of the Hong Kong catfish was constructed. The total genome was 933.4 Mb, with 416 contigs and a contig N50 length of 8.52 Mb. Using high-throughput chromosome conformation capture (Hi-C) data, the genome assembly was divided into 28 chromosomes with a scaffold N50 length of 36.68 Mb. A total of 23,345 protein-coding genes were predicted in the genome, and 94.28% of the genes were functionally annotated in public databases. Phylogenetic analysis indicated that C. fuscus and Clarias magur diverged approximately 63.7 million years ago. The comparative genome results showed that a total of 60 unique, 353 expanded and 851 contracted gene families were identified in Hong Kong catfish. A sex-linked quantitative trait locus identified in a previous study was located in a sex-determining region of 30.26 Mb (0.02 to 30.28 Mb) on chromosome 13 (Chr13), the predicted Y chromosome. This QTL region contained 785 genes, of which 18 were identified as sex-related genes.ConclusionsThis study is the first to report the chromosome-level genome assembly of Hong Kong catfish. The study provides an excellent genetic resource that will facilitate future studies of sex determination mechanisms and evolution in fish.

Antigenic Characterization of Infectious Bronchitis Virus in the South China during 2021-2022.

Avian infectious bronchitis is a serious and highly contagious disease that is caused by the infectious bronchitis virus (IBV). From January 2021 to June 2022, 1008 chicken tissue samples were collected from various regions of southern China, and 15 strains of the IBV were isolated. Phylogenetic analysis revealed that the strains mainly comprised the QX type, belonging to the same genotype as the currently prevalent LX4 type, and identified four recombination events in the S1 gene, among which lineages GI-13 and GI-19 were most frequently involved in recombination. Further study of seven selected isolates revealed that they caused respiratory symptoms, including coughing, sneezing, nasal discharge, and tracheal sounds, accompanied by depression. Inoculation of chicken embryos with the seven isolates resulted in symptoms such as curling, weakness, and bleeding. Immunization of specific pathogen-free (SPF) chickens with inactivated isolates produced high antibody levels that neutralized the corresponding strains; however, antibodies produced by vaccine strains were not effective in neutralizing the isolates. No unambiguous association was found between IBV genotypes and serotypes. In summary, a new trend in IBV prevalence has emerged in southern China, and currently available vaccines do not provide protection against the prevalent IBV strains in this region, facilitating the continued spread of IBV.

The frequency of HKαα allele in silent deletional α-thalassemia carriers in the Yulin region of southern China using the third-generation sequencing

Objectivesα-thalassemia is relatively prevalent in Yulin Region in southern China. In order to accurately detect α-globin gene aberrations for genetic counseling, the prevalence of HKαα (Hong Kong αα) allele in this subpopulation of silent deletional α-thalassemia were examined. Materials and methodsA total of 1845 subjects were selected in Yulin Region from January 2021 to March 2021. Peripheral blood was collected from each participant for routine genetic analysis of thalassemia. The HKαα allele was determined using the Single-molecule real-time (SMRT) technology for samples with -α3.7/αα, βN/βN genotype. ResultsTwo samples were identified with HKαα allele from 100 samples with -α3.7/αα, βN/βN genotype. The frequency of HKαα allele was 2.0 % (2/100) in -α3.7/αα, βN/βN carriers in Yulin Region. One sample was identified with a novel variant of the α-globin gene cluster named αHKαα by SMRT technology. One rare HBA2 variant and six HBB variants were found by SMRT technology, including -α3.7/HBA2:c.300 + 34G > A, HBB:c.316-45G > C/βN, HBB:c.315 + 180 T > C/βN, HBB:c.316-179A > C/βN. ConclusionA certain proportion of HKαα allele had been detected in Yulin Region. SMRT technology plays a crucial role for improving the diagnostic accuracy and positive detection rate of thalassemia. The completion of this study has great meaning for strengthening the prevention and control of thalassemia in Yulin Region.

Farm size increase alters the contribution of land use types to sources of river sediment

Farm size increase (FSI) accelerates soil erosion and sediment loss into the river. However, it is not clear how large-scale management, including FSI, changes the proportion of sediment from different land use types (LUTs) into rivers in intensive agricultural catchments. Thus, the aim of this study is to quantify and elucidate the contribution of different LUTs to river sediment before and after FSI using compound-specific stable isotopes (CSSI). The study was conducted in three parallel sub-watersheds in the sugarcane plantation region of subtropical southern China, each of which included four different LUTs (eucalyptus plantation, road, sugarcane plantation and channel). Following FSI, the contribution of sediment entering the river from the four LUTs was significantly different from that before FSI. The contribution per unit area of the road, sugarcane, and river channel to river sediment was significantly higher (P < 0.05) after FSI than before FSI. Overall, 1% increase in sugarcane farm size and stream channels caused > 2% and 0.3% increase contribution to river sediment, respectively. Field and road densities significantly correlated with river sediment sources. The FSI had a significant impact on the contribution of sediment entering the river from different LUTs within the watershed. Our results demonstrate that the increase river sediment depends on the increased hydrological connectivity of the watershed due to decreased field density and increased road density. Therefore, it is important to pay attention not only to the agricultural/economic benefits of FSI, but also the negative impacts on increasing erosion and ecological/environmental degradation.

Species, Habitat Characteristics, and Screening Suggestions of Cadmium Hyperaccumulators in China

Phytoremediation, as a green and effective in-situ remediation technology for heavy metal-contaminated soil, has attracted the attention of Chinese scholars and has resulted in a series of achievements over the past 20 years. In this study, the species characteristics, distribution of field discovery sites in various vegetation zones, habitat characteristics, habitat geological characteristics, and geochemistry of cadmium (Cd) of the Cd hyperaccumulators in China reported in the relevant literature from the past 20 years (from 2002 to 2021) were summarized by searching for related keywords. Finally, suggestions were proposed for the screening of new Cd hyperaccumulators. The results showed that a total of 45 species of Cd hyperaccumulators in China have been reported so far. In terms of plant species, they belonged to 22 families and 36 genera, among which Compositae with 14 species was the most abundant. There were 25 species discovered through the field investigation, which were mainly distributed in the subtropical broadleaf evergreen forest region of southern China. Additionally, the Cd hyperaccumulators discovered by field surveys were mainly found in high Cd-concentrated soils surrounding lead-zinc mines. In conclusion, abundant plant resources, high concentrations of heavy metal soils, and long-term domestication jointly promoted the formation of hyperaccumulators. Therefore, the region with these three points could be considered a high probability region for the presence of hyperaccumulators, and the screening of hyperaccumulators could be carried out around this. We proposed that the screening of new hyperaccumulators can be carried out through the following six steps:the identification and investigation of high probability areas, the enrichment capability test, the enrichment capability test in low concentration levels, the enrichment capability test between different ecotypes, the succession of enrichment capability, and the test of remediation proficiency.

Comparative Analysis of Active Ingredients and Potential Bioactivities of Essential Oils from Artemisia argyi and A. verlotorum.

Artemisia argyi H. Lév. and Vaniot is a variety of Chinese mugwort widely cultured in central China. A. verlotorum Lamotte, another variety of Chinese mugwort, has been used in the southern region of China since ancient times. Despite their similar uses in traditional medicine, little is known about the differences in their active ingredients and potential benefits. Herein, the chemical compositions of the essential oils (EOs) from both varieties were analyzed using chromatography-mass spectrometry (GC-MS). A series of databases, such as the Traditional Chinese Medicine Systems Pharmacology database (TCMSP), SuperPred database and R tool, were applied to build a networking of the EOs. Our results revealed significant differences in the chemical compositions of the two Artemisia EOs. However, we found that they shared similar ingredient-target-pathway networking with diverse bioactivities, such as neuroprotective, anti-cancer and anti-inflammatory. Furthermore, our protein connection networking analysis showed that transcription factor p65 (RELA), phosphatidylinositol 3-kinase regulatory subunit alpha (PIK3R1) and mitogen-activated protein kinase 1 (MAPK1) are crucial for the biological activity of Artemisia EOs. Our findings provided evidence for the use of A. verlotorum as Chinese mugwort in southern China.

Seasonal characteristics and spatio-temporal variations of the extreme precipitation-air temperature relationship across China

It is assumed that extreme precipitation (P) increases with air temperature (T) by a scaling rate close to 7%/°C without moisture limitation according to the Clausius-Clapeyron (C-C) relationship. However, the spatial distribution of the P-T relationship in China is subject to divergent conclusions including both sub-C-C (<7%/°C) and super-C-C (>7%/°C) scaling with reasons yet to be examined. Based on the long-term observations, here we show that P-T relationships with peak structure exist in most regions across China. The scaling rate in the wet season shows a decreasing spatial pattern from the southeast to the northwest, while sub-C-C scaling in the dry season dominates most regions across China. Mixing precipitation events from different seasons could lead to miscalculation of the P-T scaling rate. Furthermore, significant increases in peak precipitation at high percentiles have been observed in southern regions of China during the historical period, indicating that the peak structure does not imply a potential upper limit for precipitation extremes. Our results highlight the importance of considering seasonal characteristics in analyzing the extreme precipitation-temperature relationship in a changing climate.

Characteristics and driving factors of abandoned cultivated land in the hilly regions of southern China: A case study in Longnan, Jiangxi Province

Characteristics and driving factors of abandoned cultivated land in the hilly regions of southern China: A case study in Longnan, Jiangxi Province

Measurement and Analysis of Low-Frequency Radio Noise in a Typical Southern China Area

Background: External noise is a necessary factor for calculating the signal-to-noise ratio and evaluating communication quality and is one of the important parameters when designing low-frequency communication schemes or evaluating low-frequency signal quality. Methods: To study the radio noise distribution of each frequency point within the low-frequency band from 40kHz to 80kHz in a typical Southern China region at different time periods, the test team conducted a low-frequency radio noise test in Ziyang District, Yiyang City. Results and Discussion: The test data is analyzed and the results show that in this area, the radio noise in the 40kHz to 80kHz frequency band changes significantly day and night. The noise factors of most frequency points are in line with the predicted value given in the predicted value of the Radio Noise Volume of Recommendation ITU-R P.372-10. Conclusion: However, the noise distributions of 50kHz, 54kHz, 60kHz, and 68.5kHz are significantly higher than those of the predicted values.

Spatiotemporal Variation Air Quality Index Characteristics in China's Major Cities During 2014-2020.

The temporal and spatial variation characteristics of air quality index (AQI) in major cities in China were explored in this paper using statistical analysis, hot spot analysis, spatial autocorrelation, mean center, and geographic detector based on the daily AQI data from 2014 to 2020. The results show that ① the annual AQI average value dropped from 94 to 67 from 2014 to 2020. The percentage of cities with daily AQI excellent rates between 0.8 and 1 is significantly increasing, reaching 77% in 2020. ② AQI is highest and lowest in winter and summer, respectively. The trend of the monthly AQI average value is roughly in a U shape. Moreover, the AQI in January and December is high, and the AQI in August and September is low. ③ The spatial distribution of the annual AQI average in China's major cities shows agglomeration effects. The hot spots are distributed in North China and Xinjiang, and the cold spots are mainly distributed in the northeast and southern regions of China. ④ The average center of the annual AQI average of major cities in China was distributed in Sanmenxia City and Luoyang City, Henan Province, from 2014 to 2020 with a relatively small mean center migration range. ⑤ Based on the geographical detector model, the impact of total precipitation, 10-m u component of wind, 10-m v component of wind, surface pressure, and 2-m temperature on AQI is analyzed, and it is concluded that 2-m temperature has the greatest impact on AQI. Meanwhile, it is explored that GDP and population density have a certain impact on air quality. Therefore, analyzing the temporal and spatial characteristics of air quality provides some scientific basis for the regional collaborative governance of air pollution and the in-depth fight against pollution in China.

Extraction and Mapping of Cropland Parcels in Typical Regions of Southern China Using Unmanned Aerial Vehicle Multispectral Images and Deep Learning

The accurate extraction of cropland distribution is an important issue for precision agriculture and food security worldwide. The complex characteristics in southern China pose great challenges to the extraction. In this study, for the objective of accurate extraction and mapping of cropland parcels in multiple crop growth stages in southern China, we explored a method based on unmanned aerial vehicle (UAV) data and deep learning algorithms. Our method considered cropland size, cultivation patterns, spectral characteristics, and the terrain of the study area. From two aspects—model architecture of deep learning and the data form of UAV—four groups of experiments are performed to explore the optimal method for the extraction of cropland parcels in southern China. The optimal result obtained in October 2021 demonstrated an overall accuracy (OA) of 95.9%, a Kappa coefficient of 89.2%, and an Intersection-over-Union (IoU) of 95.7%. The optimal method also showed remarkable results in the maps of cropland distribution in multiple crop growth stages, with an average OA of 96.9%, an average Kappa coefficient of 89.5%, and an average IoU of 96.7% in August, November, and December of the same year. This study provides a valuable reference for the extraction of cropland parcels in multiple crop growth stages in southern China or regions with similar characteristics.

Optimal water allocation integrated with water supply, replenishment, and spill in the in-series reservoir based on an improved decomposition and dynamic programming aggregation method

Abstract In humid regions with the monsoon climate, seasonal water shortages and water spills occur alternately because of uneven temporal and spatial distributions of water resources. An optimization model for the in-series reservoir (ISR) with replenishment pumping stations was developed to obtain the minimum annual sum of water shortage and systematically considered the reservoir operation rule of water spill and replenishment. This model features multiple dimensions; dynamic programming (DP) may cause a ‘curse of dimensions’, while the decomposition-coordination method has difficulty in judging logic conditions in the reservoir operation rules. So, an improved decomposition and DP aggregation (DDPA) method was proposed. The proposed model and the method were applied to a real case in the humid region of southern China. Compared to a conventional scheduling method, the water supply was increased by 0.8% and replenishment was reduced by 2.5%. Moreover, a comparison between DDPA and six heuristic algorithms was discussed. All heuristic algorithms' objective function values only obtained local optimal solutions, and the water shortage of the system was 0.12–20.5%. The obtained results demonstrated that DDPA was the better choice for highly complex multi-reservoir systems. The proposed optimization algorithm enriched the optimization theory of multi-dimensional and multi-variable complex systems.

Rare microbial communities drive ecosystem multifunctionality in acidic soils of southern China

Soil microbial communities are important for maintaining ecosystem multifunctionality, and abundant and rare sub-communities often have fundamentally different characteristics and ecological roles. However, little is known about the links between microbial sub-communities and soil multifunctionality in acidic soils across large spatial scales. Here, we collected 52 soil samples from four locations spanning 961.3 km in the acidic soil region of southern China and characterized bacterial and fungal sub-communities and their contributions to soil multifunctionality. Sub-community compositions of both rare bacteria and rare fungi significantly explained changes in soil multifunctionality, but abundant sub-communities were not significantly related to soil multifunctionality. This suggested that soil multifunctionality might be mainly controlled by rare microbes in acidic soils. Rare fungal α-diversity, rather than rare bacterial α-diversity, was significantly and positively correlated with multifunctionality. Deterministic processes were the primary drivers of the sub-community assembly of rare bacteria and rare fungi and thus might have an important effect on soil multifunctionality. Soil pH was the most dominant soil factor driving rare bacterial and fungal sub-community structures and affecting soil multifunctionality. In the co-occurrence networks of bacterial and fungal communities, most of the keystone taxa were rare species. The numbers of positive interactions of rare fungal taxa, but not rare bacterial taxa, were positively related to soil multifunctionality. Our results provided evidence that rare microbial sub-communities are important for maintaining ecosystem multifunctionality in acidic soils, and rare bacteria and fungi may display the potentially different mechanisms to drive ecosystem functions.

The characteristics of the complete chloroplast genome of Staurogyne concinnula (Hance) O. Kuntze (Acanthaceae)

Staurogyne concinnula (Hance) O. Kuntze (Acanthaceae) is an important ornamental herb mainly distributed in the southern region of China, including Fujian, Guangdong, Hainan, and Taiwan provinces. However, the complete chloroplast genome of S. concinnula, which could serve as a genetic resource for studies on its taxonomy and evolution, is poorly studied at present. In this study, we reported the complete chloroplast genome of S. concinnula that was assembled using high-throughput sequencing data. The chloroplast genome was 153,783 bp long, with a typical quadripartite structure containing a small single-copy region (SSC; 17,855 bp), a large single-copy region (LSC; 84,636 bp) and a pair of inverted repeats (IRs; each 25,646 bp). The overall GC content of the chloroplast genome was 38.04%. A total of 86 protein-coding genes (PCGs), 8 rRNA genes, and 37 tRNA genes were predicted. Phylogenetic analysis based on the combined sequences of 86 PCGs with the other 16 closely related species of Acanthaceae indicated that S. concinnula is closely related to Avicennia marina. The genomic data and finding from the phylogenetic studies of S. concinnula could provide useful information and give light to in-depth studies on the evolution pattern of the understudied species, as well as Staurogyne.