Project description:Background: The soil environment is responsible for sustaining most terrestrial plant life on earth, yet we know surprisingly little about the important functions carried out by diverse microbial communities in soil. Soil microbes that inhabit the channels of decaying root systems, the detritusphere, are likely to be essential for plant growth and health, as these channels are the preferred locations of new root growth. Understanding the microbial metagenome of the detritusphere and how it responds to agricultural management such as crop rotations and soil tillage will be vital for improving global food production. Methods: The rhizosphere soils of wheat and chickpea growing under + and - decaying root were collected for metagenomics sequencing. A gene catalogue was established by de novo assembling metagenomic sequencing. Genes abundance was compared between bulk soil and rhizosphere soils under different treatments. Conclusions: The study describes the diversity and functional capacity of a high-quality soil microbial metagenome. The results demonstrate the contribution of the microbiome from decaying root in determining the metagenome of developing root systems, which is fundamental to plant growth, since roots preferentially inhabit previous root channels. Modifications in root microbial function through soil management, can ultimately govern plant health, productivity and food security.
Project description:Large-scale intensive cultivation has made continuous cropping soil sickness more serious for Panax notoginseng in Yunnan. Autotoxic substances can promote the occurrence of continuous cropping soil sickness. Phenolic acids exert a strong autotoxic effect on P. notoginseng. Based on UPLC-MS/MS, the levels of six phenolic acids with the strongest autotoxicity of P. notoginseng rhizospheric soil were tested. Based on Illumina MiSeq high-throughput sequencing technology, the variation in the microbial diversity in the rhizospheric soil was used as an index to explore the interactions between phenolic acids and the soil microorganisms of the P. notoginseng rhizosphere. (1) Continuous P. notoginseng cropping significantly changed the microbial community structure. Continuous cropping increased bacterial Chao1 index and Shannon index and decreased fungal Shannon index. After P. notoginseng disease, bacterial Shannon index reduced and fungal Chao1 index decreased. (2) Phenolic acid significantly changed the bacterial community structure. VA significantly reduced the bacterial Shannon index. Exogenous p-HA, FA, SA, and VA significantly increased the fungal Chao1 index and p-HA showed the most significant effect. Para-HA affected bacterial specificity, and VA affected fungal specificity. (3) VA was positively correlated with most fungi and bacteria. Para-HA was positively correlated with Lelliottia and Flavobacterium. Para-HA was also positively correlated with plant pathogens (Fusarium and Ilyonectria). Para-HA and VA were able to promote the growth of primary pathogenic bacteria. Thus, p-HA and VA are the main phenolic acid-autotoxin substances in P. notoginseng under continuous cropping. (4) A correlation analysis of soil environmental factors associated with fungal and bacterial communities showed that AK, TN, OM, and HN were most strongly correlated with soil microorganisms. (5) The microorganisms in the rhizosphere of 3-year-old soil planted with P. notoginseng exhibited obvious effects on the degradation of the four phenolic acids. The effect of soil microorganisms on phenolic acids was first-order kinetic degradation with a high degradation rate and a half-life of less than 4.5 h. The results showed that phenolic acids could promote the growth of pathogenic bacteria. And the interaction between rhizospheric soil microorganisms and phenolic acids was the main cause of the disturbance of P. notoginseng rhizosphere microflora.
Project description:BackgroundRhizospheric fungi play an essential role in the plant-soil ecosystem, affecting plant growth and health. In this study, we evaluated the fungal diversity in the rhizosphere soil of 2-yr-old healthy Panax notoginseng cultivated in Wenshan, China.MethodsCulture-independent Illumina MiSeq and culture-dependent techniques, combining molecular and morphological characteristics, were used to analyze the rhizospheric fungal diversity. A diffusion test was used to challenge the phytopathogens of P. notoginseng.ResultsA total of 16,130 paired-end reads of the nuclear ribosomal internal transcribed spacer 2 were generated and clustered into 860 operational taxonomic units at 97% sequence similarity. All the operational taxonomic units were assigned to five phyla and 79 genera. Zygomycota (46.2%) and Ascomycota (37.8%) were the dominant taxa; Mortierella and unclassified Mortierellales accounted for a large proportion (44.9%) at genus level. The relative abundance of Fusarium and Phoma sequences was high, accounting for 12.9% and 5.5%, respectively. In total, 113 fungal isolates were isolated from rhizosphere soil. They were assigned to five classes, eight orders (except for an Incertae sedis), 26 genera, and 43 species based on morphological characteristics and phylogenetic analysis of the internal transcribed spacer. Fusarium was the most isolated genus with six species (24 isolates, 21.2%). The abundance of Phoma was also relatively high (8.0%). Thirteen isolates displayed antimicrobial activity against at least one test fungus.ConclusionOur results suggest that diverse fungi including potential pathogenic ones exist in the rhizosphere soil of 2-yr-old P. notoginseng and that antagonistic isolates may be useful for biological control of pathogens.
Project description:Metagenome data from soil samples were collected at 0 to 10cm deep from 2 avocado orchards in Channybearup, Western Australia, in 2024. Amplicon sequence variant (ASV) tables were constructed based on the DADA2 pipeline with default parameters.
Project description:This data set contains 1376 mass spectrometry reads from root, rhizosphere and leaf sample of Populus Trichocarpa, as well as associated controls. This metabolomics data set was collected as part of a larger campaign which complements the metabolomics data with metagenome sequencing, transcriptomics, and soil measurement data.
Project description:Recent results demonstrated that either non-coding or coding genes generate phased secondary small interfering RNAs (phasiRNAs) guided by specific miRNAs. Till now, there is no studies for phasiRNAs in Panax notoginseng (Burk.) F.H. Chen (P. notoginseng), an important traditional Chinese herbal medicinal plant species. Here we performed a genome-wide discovery of phasiRNAs and its host PHAS loci in P. notoginseng by analyzing small RNA sequencing profiles. Degradome sequencing profile was used to identify the trigger miRNAs of these phasiRNAs and potential targets of phasiRNAs. We also used RLM 5'-RACE to validate some of the identified phasiRNA targets. After analyzing 24 small RNA sequencing profiles of P. notoginseng, 204 and 90 PHAS loci that encoded 21 and 24 nucleotide (nt) phasiRNAs were identified. Furthermore, we found that phasiRNAs produced from some pentatricopeptide repeat-contain (PPR) genes target another layer of PPR genes as validated by both the degradome sequencing profile and RLM 5'-RACE analysis. We also find that miR171 with 21 nt triggers the 21 nt phasiRNAs from its conserved targets. We validated that some phasiRNAs generated from PPRs are functional by targeting other PPRs in trans. These results provide the first set of PHAS loci and phasiRNAs in P. notoginseng, and enhance our understanding of PHAS in plants.
Project description:The goal of this growth chamber experiment was to investigate the effects of diverse soil microbial communities on the transcriptional responses of plants to drought. Specifically, we sought to understand how soil microbiomes' past exposure to water-limited conditions (either long-term exposure to dry conditions in low-precipitation sites, or recent acute drought) impacted their interactions with plants. Six soils collected from remnant prairies crossing a steep precipitation gradient in Kansas, USA were used as the starting microbial communities. Thirty-two pots (or mesocosms) of each soil were divided among four treatments: droughted or well-watered, and with or without a host plant (Tripsacum dactyloides) in a factorial design. The soil mesocosms were "conditioned" in these treatments for five months. (Metagenome and metatranscriptome data from the baseline soils and the post-conditioning soils are available in a separate BioProject on NCBI SRA and GEO). Then, a microbial slurry extracted from each of the 192 conditioned soils was used to inoculate 4 plants in a subsequent experiment (the “Test Phase”): one pot per combination of watering treatment (droughted or control) and host species (Zea mays or Tripsacum dactyloides). After 4 weeks (for maize) or 5 weeks (for eastern gamagrass) we harvested one crown root per plant for 16S rRNA sequencing and another crown root for RNA-seq. The 16S and RNA-seq data for these plants (both species) are contained in this BioProject. Note that 16S rRNA sequencing data are available for all plants in this experiment, but we conducted RNA-seq only for a subset (all plants grown in microbiomes originating from the 2 driest and 2 wettest collection sites).