Excessive application of chemical fertilizer has caused many problems in Angelica dahurica var. formosana planting, such as yield decline and quality degradation. In order to promote the green cultivation mode of A. dahurica var. formosana and explore rhizosphere fungus resources, the rhizosphere fungi with nitrogen fixation, phosphorus solubilization, potassium solubilization, iron-producing carrier, and IAA-producing properties were isolated and screened in the rhizosphere of A. dahurica var. formosana from the genuine and non-genuine areas, respectively. The strains were identified comprehensively in light of the morphological characteristics and ITS rDNA sequences, and the growth-promoting effect of the screened strains was verified by pot experiment. The results showed that 37 strains of growth-promoting fungi were isolated and screened from the rhizosphere of A. dahurica var. formosana, mostly belonging to Fusarium. The cultured rhizosphere growth-promoting fungi of A. dahurica var. formosana were more abundant and diverse in the genuine producing areas than in the non-genuine producing areas. Among all strains, Aspergillus niger ZJ-17 had the strongest growth promotion potential. Under the condition of no fertilization outdoors, ZJ-17 inoculation significantly promoted the growth, yield, and accumulation of effective components of A. dahurica var. formosana planted in the soil of genuine and non-genuine producing areas, with yield increases of 73.59% and 37.84%, respectively. To a certain extent, it alleviated the restriction without additional fertilization on the growth of A. dahurica var. formosana. Therefore, A. niger ZJ-17 has great application prospects in increasing yield and quality of A. dahurica var. formosana and reducing fertilizer application and can be actually applied in promoting the growth of A. dahurica var. formosana and producing biofertilizer.
Fertilizers ; Rhizosphere ; Angelica/chemistry* ; Fungi/genetics* ; Phosphorus

This study aimed to explore the correlation between rhizosphere soil microorganisms of wild Arnebia euchroma and the content of medicinal components to provide guidance for the selection of the ecological planting base. The total DNA of rhizosphere soil microorganisms of wild A. euchroma was extracted, and the microbial community structure of rhizosphere soil microorganisms was analyzed by IlluminaMiseq high-throughput sequencing technology. The content of total hydroxynaphthoquinone pigment and β,β'-dimethylacrylalkannin in medicinal materials was determined by high-performance liquid chromatography(HPLC). The physicochemical pro-perties of rhizosphere soil of wild A. euchroma in main producing areas were determined, and the correlation of soil microbial abundance with index component content and soil physicochemical properties was analyzed by SPSS software. The results showed that the species composition of rhizosphere fungi and bacteria in A. euchroma from different habitats was similar at the phylum and genus levels, but their relative abundance, richness index(Chao1), and community diversity(Simpson) index were different. Correlation analysis showed that the content of available phosphorus in soil was positively correlated with the content of total hydroxynaphthoquinone pigment and β,β'-dimethylacrylalkannin, and the abundance of five fungal genera such as Solicoccozyma and six bacterial genera such as Pseudo-nocardia and Bradyrhizobium was positively correlated with the content of medicinal components in medicinal materials. The abundance of Bradyrhizobium was significantly positively correlated with the content of β,β'-dimethylacrylalkanin. The abundance of fungi such as Archaeorhizomyces was significantly positively correlated with the content of available phosphorus in rhizosphere soil, and Bradyrhizobium was significantly negatively correlated with soil pH. Therefore, the abundance of fungi and bacteria in the rhizosphere of A. euchroma has a certain correlation with the medicinal components and the physicochemical properties of the rhizosphere soil, which can provide a scientific basis for the selection of ecological planting bases in the later stage.
Rhizosphere ; Soil Microbiology ; Bacteria/genetics* ; Phosphorus ; Soil ; Boraginaceae

To explore the changes and the reaction mechanisms between soil microecological environment and the content of secon-dary metabolites of plants under water deficit, this study carried out a pot experiment on the 3-leaf stage seedlings of Rheum officinale to analyze their response mechanism under different drought gradients(normal water supply, mild, moderate, and severe drought). The results indicated that the content of flavonoids, phenols, terpenoids, and alkaloids in the root of R. officinale varied greatly under drought stresses. Under mild drought stress, the content of substances mentioned above was comparatively high, and the content of rutin, emodin, gallic acid, and(+)-catechin hydrate in the root significantly increased. The content of rutin, emodin, and gallic acid under severe drought stress was significantly lower than that under normal water supply. The number of species, Shannon diversity index, richness index, and Simpson index of bacteria in the rhizosphere soil were significantly higher than those in blank soil, and the number of microbial species and richness index decreased significantly with the aggravation of drought stresses. In the context of water deficit, Cyanophyta, Firmicutes, Actinobacteria, Chloroflexi, Gemmatimonadetes, Streptomyces, and Actinomyces were the dominant bacteria in the rhizosphere of R. officinale. The relative content of rutin and emodin in the root of R. officinale was positively correlated with the relative abundance of Cyanophyta and Firmicutes, and the relative content of(+)-catechin hydrate and(-)-epicatechin gallate was positively correlated with the relative abundance of Bacteroidetes and Firmicutes. In conclusion, appropriate drought stress can increase the content of secondary metabolites of R. officinale from physiological induction and the increase in the association with beneficial microbe.
Rhizosphere ; Rheum ; Droughts ; Soil ; Catechin ; Emodin ; Bacteria/metabolism* ; Water/metabolism* ; Firmicutes ; Soil Microbiology

The natural forest and artificial shed are the main cropping modes of Coptis chinensis. This study is aimed to reveal the rhizosphere soil bacterial community structure difference between under tow C. chinensis cropping modes-natural forest and artificial shed, and to assist us to completely understand soil quality condition,and provide theoretical guidance for soil improvement and C. chinensis planting. The rhizosphere soil samples of 1-5-year-old C. chinensis under tow cropping modes-natural forest and artificial shed were collected. Illumina high-throughput sequencing technology was used to analyze the alpha diversity, community composition, community structure of soil bacteria under the tow cropping modes,and the effects of soil nutriment indices on soil bacterial community structure. Through the analysis of species number, Shannon, Chao1 index and ACE index of bacterial community, it was found that the bacterial diversity of 1-year-old C. chinensis soil under natural forest cropping mode was significantly lower than that under artificial shed cropping mode, and the diversity of bacterial communities in soil of 2-5-years old C. chinensis were not significant different between two cropping modes. A total of 53 phyla,60 classes,140 orders and 266 families were detected in the rhizosphere soil of C. chinensis under the cropping modes of natural forest, respectively. The rhizosphere soil of C. chinensis under the cropping modes of artificial shed included 54 phyla,65 classes,140 orders and 264 families, respectively. Under the two cropping modes, the top 10 dominant species of bacterial community abundance are the same, they are Proteobacteria, Acidobacteria, Actinobacteria,Bacteroidetes, Planctomycetes, Chloroflexi, Verrucomicrobia, Gemmatimonadetes, Firmicutes and Cyanobacteria, but there are differences in the abundance sequence. The top 10 dominant species of bacterial community abundance accounted for 74.36% to 74.30% of the total bacteria, and 3.15% to 3.92% of the bacteria are unclassified. The results of Metastat analysis showed that the abundance of Gemmatimonadetes in the rhizosphere soil of C. chinensis under the cropping modes the artificial shed was significantly higher than that under the natural forest cropping mode(P<0.05). MRPP analysis of community structure differences showed that under tow cropping modes, there were significant differences in the bacterial community structure of 1-4-year-old soil bacteria, among which the difference between 1-year-old soil samples was the largest. With the increase of cropping years, the difference gradually decreases, and there is no significant difference in the bacterial community structure between 5-year-old soil samples. RDA analysis and correlation analysis of bacterial community structure and soil physical and chemical properties showed that the order of environmental factors on the rhizosphere soil bacteria of Coptis chinensis was: pH>available P> total P> total K>bulk density>total N>available N>organic matter. The results are helpful to understand the soil health of C. chinensis and provide scientific basis and theoretical guidance for soil improvement and C. chinensis planting.
Child, Preschool ; Coptis ; Forests ; Humans ; Infant ; Rhizosphere ; Soil ; Soil Microbiology

The study aiming at exploring the potassium-dissolving capacity of rhizosphere potassium-dissolving bacteria from diffe-rent sources and screen the strains with high potassium-dissolving ability, so as to lay a theoretical foundation for cultivation and quality improvement of Paris polyphylla var. yunnanensis sources. The rhizosphere soil of 10 wild and transplanted species from Yunnan, Sichuan and Guizhou provinces was used as the research object. Potassium-dissolving bacteria were isolated and purified, and their potassium-dissolving capacity was determined by flame spectrophotometry, and identified by physiological, biochemical and molecular biological methods. Twenty-six potassium-dissolving bacteria were purified and 13 were obtained from wild and transplanted strains respectively. It was found through the determination of potassium-dissolving capacity that the potassium-dissolving capacity of 26 strains was significantly different, and the mass concentration of K~+ in the fermentation broth were 1.04-2.75 mg·L~(-1), the mcentration of potassium were 0.01-1.82 mg·L~(-1). The strains were identified as Bacillus, Agrobacterium rhizome and Staphylococcus by physiological, biochemical and 16 S rDNA molecular methods, among them Bacillus amylolyticus(4 strains) was the dominant bacterium of Bacillus. The physiology and biochemistry of rhizosphere potassium-dissolving bacteria in P. polyphylla var. yunnanensis rhizosphere were diffe-rent, and the living environment were different, so the potassium-dissolving capacity also changed. Strain Y4-1 with the highest potassium decomposability was Bacillus amylolytic with a potassium increase of 1.82 mg·L~(-1). The potassium-dissolving ability and the distribution of potassium-dissolving bacteria were different in various habitats. The screening of potassium-dissolving bacteria provided a new strain for the preparation of microbial fertilizer. It is expected that B. amyloidococcus Y4-1 can be used as an ideal strain to cultivate mycorrhizal seedlings of P. polyphylla var. yunnanensis.
China ; Liliaceae ; Paenibacillus ; Potassium ; Rhizosphere ; Soil

Aims: Knowledge of the Trichoderma taxa is important for both control efficiency and environmental conservation. Therefore, the objective of this study is to isolate and identify Trichoderma species from various rhizosphere soil samples using phenotypic and molecular characterization. Methodology and results: Native Trichoderma spp. were isolated from agricultural fields in 17 sites from seven states of Malaysia. These isolates were characterized via morphological observation and molecular phylogenetic analysis based on the translation elongation factor-1α (tef1-α) gene. About 42 isolates were classified into eight Trichoderma species, which are Trichoderma asperellum, T. hamatum, T. harzianum, T. koningiopsis, T. rodmanii, T. spirale, T. viride and T. virens. Comparison of DNA sequences of tef1-α showed that the isolates were 98-100% similar to respective Trichoderma species from GenBank, thus confirming the fungal identity. Phylogenetic trees of maximum likelihood (ML) dataset of tef1-α inferred that the isolates were clustered according to species. Conclusion, significance and impact of study Findings in the present study will be beneficial for the purposes of biodiversity conservation and plant disease management using biocontrol agents.
Trichoderma--isolation & ; purification ; Rhizosphere

Aquatic plants and the epiphytic microorganisms are important contributors to the purification of constructed wetlands. Taking the dragon-shaped water system of Beijing Olympic Park as a model, this study analyzed the structure and function of the microbial communities reside the sediment, the water body and the rhizosphere and phyllosphere of three submerged plants-Vallisneria natans, Myriophyllum verticillatum, and Potamogeton pectinatus using high-throughput sequencing technology. The results showed that the microbial diversity from the highest to the lowest were samples from sediment, plant rhizosphere, plant phyllosphere and water. The microbial diversity of plant phyllosphere samples were significantly higher than those of the water body. LEfSe analysis showed that different habitats enriched different microbial groups. The sediments mainly enriched anaerobic microbes, while the water body and the phyllosphere of plants mainly enriched aerobic microbes, and the rhizosphere of plants had the both. Functional prediction analysis showed that the abundance of denitrification marker genes in phyllosphere samples was higher than that in samples from rhizosphere, sediment and water body, and the abundance of denitrification marker genes in phyllosphere samples of M. verticillatum and P. pectinatus was higher than that of V. natans. This study could serve as a guidance for the selection of submerged plants and functional microorganisms for constructed wetlands.
Beijing ; Hydrocharitaceae ; Microbiota ; Rhizosphere ; Water

Aims: Plant growth promoting rhizobacteria (PGPR) is a group of bacteria that colonise plant roots and enhance plant growth by a diverse range of mechanisms. This study aims to determine the capabilities of PGPR isolated from cocoa tree roots and their efficiency in enhancing plant growth under greenhouse conditions. Methodology and results: Eight samples of healthy cocoa tree roots were collected from different locations in Malaysia. Isolated bacteria were screened based on nitrogen fixation, phosphate and potassium solubilization, and catalase activity. The efficiency of purified PGPR was evaluated from pot experiments of cocoa seedlings under greenhouse conditions. Out of 122 isolates, 18 isolates showed several traits of nitrogen fixation, phosphorus and potassium solubilization and were further screened for other plant growth promoting (PGP) traits like catalase and production of indole acetic acid (IAA). Out of all the PGP trait tests, seven isolates showed the most prominent results for in vitro tests and were further tested in vivo for growth promotion of cocoa seedlings under greenhouse conditions. In the presence of bacterial isolates with 2.5 g of inorganic fertilizer, Leclercia adecarboxylata resulted in increases in plant height, leaf number, root length, stem fresh weight and total fresh and dry weight of cocoa seedlings by 15.68%, 17.14%, 9.48%, 5.67%, 11.84% and 25.12%, respectively. Conclusion, significance and impact of study Based on the result, L. adecarboxylata incorporated with selected carrier material improve cocoa seedling growth and biomass. This formulation also reduces the production cost of inorganic fertilizer and increase the application and development of biofertilizer.
Cacao--growth & ; development ; Rhizosphere

Aims: The purpose of this research was to explore the composition and genomic functions of bacterial community inhabiting the rhizosphere of Mimosa pudica, which were naturally growing on tailing and non-tailing soils of an ex-tin mining area. Methodology and results: DNA were extracted from rhizosphere soils and PCR targeting the hypervariable region V3-V4 was carried out by Illumina 16S metagenomic library. Libraries were sequenced using Illumina MiSeq. The Operational Taxonomic Units (OTUs) were assigned to 23 bacterial phyla, 72 classes, 165 orders, 248 families and 357 genera. The most represented and dominant phylum was Proteobacteria, with an average abundance value of 41.2%. The most represented genera included Paraburkholderia, Bradyrhizobium, Bacillus, Candidatus, Acidothermus, Acidibacter and Nitrospira. Non-tailing soils had more number and richness of species while the tailings had more diversity of species. The metagenomes accommodate suspected genes for heavy metal tolerance of microbes (As, Cr, Co, Zn, Ni, Cu, Cd, Fe and Hg) and microbial plant-growth-promoting traits for hyperaccumulator plants (synthesis of indole acetic acid (IAA), siderophore and 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase; solubilization of phosphate and potassium and nitrogen fixation). Conclusion, significance and impact of study Bacteria and predicted genes discovered could be part of major factors influencing growth of M. pudica in heavy metal-contaminated soils. The study provides the first report and a basis into the bacterial community associated with M. pudica in ex-tin mining soils from the studied geographical location. The findings also provide fundamental knowledge on phytoremediation potential of heavy metal contaminated soils involving indigenous beneficial microbial populations.
Bacteria ; Rhizosphere ; Mimosa ; Plant Growth Regulators

Rhizosphere is the main place for the communication between medicinal plants and rhizosphere microorganisms. Medicinal plants are closely related to the diversity and richness of rhizosphere microorganisms, and rhizosphere microorganisms in the rhizosphere of medicinal plants have important effects on the growth and development, yield, quality and resilience of medicinal plants. The reasonable and effective utilization of the principle of interaction between medicinal plants and rhizosphere microorganisms has practical guiding significance for promoting the growth of medicinal plants, enhancing the ability of resistance to diseases and resisting the invasion of pathogens. This paper reviewed the research status of medicinal plants and rhizosphere microorganisms in recent years, including the influence of medicinal plants on rhizosphere microorganisms, the influence of rhizosphere microorganisms on medicinal plants and the mechanism of interaction between medicinal plants and rhizosphere microorganisms. The problems existing in the study of medicinal plants and rhizosphere microorganisms and the direction for further study were also pointed out.
Plant Roots ; Plants, Medicinal ; Rhizosphere ; Soil Microbiology