Project description:<p><strong>BACKGROUND:</strong> The coevolution and interaction between plants and microorganisms have long been a subject of significant research interest. Dark septate endophytes (DSE) have garnered great attention in contemporary research due to their functional diversity, in vitro cultivation ability, and ability to establish symbiotic associations with host plants. In the present study, three DSE strains, namely <em>Acrocalymma vagum</em>, <em>Zopfiella marina</em>, and <em>Phoma herbarum</em>, which were obtained from the roots of <em>Astragalus membranaceus</em>, were introduced into maize plants through inoculation. We evaluated the effects of DSE inoculation on maize growth and root secretion activity through a multi omics methods, and proposed mechanisms for 'internal pathways' and 'external pathways'.</p><p><strong>RESULTS:</strong> The findings indicated that A. vagum exhibited superior growth-promoting ability on maize compared to <em>Z. marina</em> and <em>P. herbarum</em>.GO and KEGG enrichment analysis found that <em>A. vagum</em> inoculation resulted in significant enrichment of differentially expressed genes in annotation functions related to hormone regulation and lipid metabolism. A. vagum inoculation revealed that the gene pathways involved in plant hormone signaling and plant pathogen interactions play a crucial role in promoting host growth, and <em>A. vagum</em> inoculation group exhibited the highest number of differentially expressed genes, the most intricate protein-protein interaction (PPI) model, and the most pronounced relationship between differentially expressed genes. After the inoculation of <em>A.vagum</em>, the levels of salicylic acid, zeatin, and IAA in maize plants significantly increased. Additionally, the diversity and abundance of endophytic fungi, as well as the proportion of harmful bacteria and beneficial fungi, had significantly increased. Compared with <em>Z. marina</em> and <em>P. herbarum</em>, the net photosynthetic rate (Pn) and stomatal conductance (Gs) of <em>A.vagum</em> inoculated plants significantly increased. Inoculation with <em>A.vagum</em> could enhance the ability of corn roots to secrete lipids, sugars, and amino acids, resulted in a notable augmentation of beneficial bacteria and fungi, accompanied by a significant reduction in the proportion of harmful bacteria in the rhizosphere soil, such as <em>Fusarium solani</em> and <em>Fusarium lacertarum</em>, exhibited significant inhibition, whereas <em>Bacillus niabensis</em> and <em>Bacillus nealsonii</em> demonstrated enrichment trends. Soil pH, organic matter, available potassium content, acid phosphatase, alkaline phosphatase and urease activity exhibited significant increases following the inoculation of <em>A. vagum</em>. Variance decomposition and structural equation modeling (SEM) analysis indicated that the 'internal pathway', maize growth is mainly influenced by the interaction of endogenous hormones, endophytic microorganisms, and photosynthetic parameters, whereas within the 'external pathway', the interaction between soil microorganisms and soil physicochemical properties exerted a dominant influence. Compared with the <em>Z. marina</em> and <em>P. herbarum</em> inoculation, <em>A. vagum</em> inoculation showed a more significant impact on maize growth, both in terms of 'internal pathway' and 'external pathway', in terms of pathway level and quantity.</p><p><strong>CONCLUSIONS:</strong> These findings provide a new perspective for understanding the potential mechanisms of 'microbe-plant' interactions and also contribute to the exploration of targeted functional microorganisms that promote growth and stress resistance.</p>
Project description:Soil transplant serves as a proxy to simulate climate change in realistic climate regimes. Here, we assessed the effects of climate warming and cooling on soil microbial communities, which are key drivers in Earth’s biogeochemical cycles, four years after soil transplant over large transects from northern (N site) to central (NC site) and southern China (NS site) and vice versa. Four years after soil transplant, soil nitrogen components, microbial biomass, community phylogenetic and functional structures were altered. Microbial functional diversity, measured by a metagenomic tool named GeoChip, and phylogenetic diversity are increased with temperature, while microbial biomass were similar or decreased. Nevertheless, the effects of climate change was overridden by maize cropping, underscoring the need to disentangle them in research. Mantel tests and canonical correspondence analysis (CCA) demonstrated that vegetation, climatic factors (e.g., temperature and precipitation), soil nitrogen components and CO2 efflux were significantly correlated to the microbial community composition. Further investigation unveiled strong correlations between carbon cycling genes and CO2 efflux in bare soil but not cropped soil, and between nitrogen cycling genes and nitrification, which provides mechanistic understanding of these microbe-mediated processes and empowers an interesting possibility of incorporating bacterial gene abundance in greenhouse gas emission modeling.
Project description:Expression profiling analyses for 5 maize inbreds and 4 hybrids, chosen to represent diversity in genotypes and heterosis responses, revealed a correlation between genetic diversity and transcriptional variation. This is a companion dataset to an Affymetrix profiling experiment (GEO Series GSE10236). Keywords: Genotype comparison series
Project description:Because of severe abiotic limitations, Antarctic soils represent simplified ecosystems, where microorganisms are the principle drivers of nutrient cycling. This relative simplicity makes these ecosystems particularly vulnerable to perturbations, like global warming, and the Antarctic Peninsula is among the most rapidly warming regions on the planet. However, the consequences of the ongoing warming of Antarctica on microorganisms and the processes they mediate are unknown. Here, using 16S rRNA gene pyrosequencing and qPCR, we report a number of highly consistent changes in microbial community structure and abundance across very disparate sub-Antarctic and Antarctic environments following three years of experimental field warming (+ 0.5-2°C). Specifically, we found significant increases in the abundance of fungi and bacteria and in the Alphaproteobacteria-to-Acidobacteria ratio. These alterations were linked to a significant increase in soil respiration. Furthermore, the shifts toward generalist or opportunistic bacterial communities following warming weakened the linkage between bacterial diversity and functional diversity. Warming also increased the abundance of some organisms related to the N-cycle, detected as an increase in the relative abundance of nitrogenase genes via GeoChip microarray analyses. Our results demonstrate that soil microorganisms across a range of sub-Antarctic and Antarctic environments can respond consistently and rapidly to increasing temperatures, thereby potentially disrupting soil functioning.
Project description:Soil transplant serves as a proxy to simulate climate change in realistic climate regimes. Here, we assessed the effects of climate warming and cooling on soil microbial communities, which are key drivers in EarthM-bM-^@M-^Ys biogeochemical cycles, four years after soil transplant over large transects from northern (N site) to central (NC site) and southern China (NS site) and vice versa. Four years after soil transplant, soil nitrogen components, microbial biomass, community phylogenetic and functional structures were altered. Microbial functional diversity, measured by a metagenomic tool named GeoChip, and phylogenetic diversity are increased with temperature, while microbial biomass were similar or decreased. Nevertheless, the effects of climate change was overridden by maize cropping, underscoring the need to disentangle them in research. Mantel tests and canonical correspondence analysis (CCA) demonstrated that vegetation, climatic factors (e.g., temperature and precipitation), soil nitrogen components and CO2 efflux were significantly correlated to the microbial community composition. Further investigation unveiled strong correlations between carbon cycling genes and CO2 efflux in bare soil but not cropped soil, and between nitrogen cycling genes and nitrification, which provides mechanistic understanding of these microbe-mediated processes and empowers an interesting possibility of incorporating bacterial gene abundance in greenhouse gas emission modeling. Fifty four samples were collected from three soil types (Phaeozem,Cambisol,Acrisol) in three sites (Hailun, Fengqiu and Yingtan) along a latitude with reciprocal transplant; Both with and without maize cropping in each site; Three replicates in every treatments.
Project description:Expression profiling analyses for 5 maize inbreds and 4 hybrids, chosen to represent diversity in genotypes and heterosis responses, revealed a correlation between genetic diversity and transcriptional variation. This is a companion dataset to an Affymetrix profiling experiment (GEO Series GSE10236). Keywords: Genotype comparison series Expression profiling was used to study gene expression in aerial tissue from 11-day seedlings of maize. Three biological replicates were performed for nine different genotypes; B37, B73, B84, Mo17, Oh43, B37xB73, B84xB73, Oh43xB73 and Oh43xMo17.
Project description:Because of severe abiotic limitations, Antarctic soils represent simplified ecosystems, where microorganisms are the principle drivers of nutrient cycling. This relative simplicity makes these ecosystems particularly vulnerable to perturbations, like global warming, and the Antarctic Peninsula is among the most rapidly warming regions on the planet. However, the consequences of the ongoing warming of Antarctica on microorganisms and the processes they mediate are unknown. Here, using 16S rRNA gene pyrosequencing and qPCR, we report a number of highly consistent changes in microbial community structure and abundance across very disparate sub-Antarctic and Antarctic environments following three years of experimental field warming (+ 0.5-2°C). Specifically, we found significant increases in the abundance of fungi and bacteria and in the Alphaproteobacteria-to-Acidobacteria ratio. These alterations were linked to a significant increase in soil respiration. Furthermore, the shifts toward generalist or opportunistic bacterial communities following warming weakened the linkage between bacterial diversity and functional diversity. Warming also increased the abundance of some organisms related to the N-cycle, detected as an increase in the relative abundance of nitrogenase genes via GeoChip microarray analyses. Our results demonstrate that soil microorganisms across a range of sub-Antarctic and Antarctic environments can respond consistently and rapidly to increasing temperatures, thereby potentially disrupting soil functioning. We conducted in situ warming experiments for three years using open-top chambers (OTCs) at one sub-Antarctic (Falkland Islands, 52ºS) and two Antarctic locations (Signy and Anchorage Islands, 60ºS and 67ºS respectively) (see Supplementary Fig. 1 for a map). OTCs increased annual soil temperature by an average of 0.8°C (at a depth of 5 cm), resulting in 8-43% increase in positive-degree days annually and a decrease in freeze-thaw cycle frequency by an average of 15 cycles per year (8). At each location, we included densely vegetated and bare fell-field soils in the experimental design for a total of six environments. Densely vegetated and bare environments represent two contrasting environments for Antarctic soil microorganisms, with large differences in terms of C and N inputs to soils. Massively parallel pyrosequencing (Roche 454 GS FLX Titanium) of 16S rRNA gene amplicons was used to follow bacterial diversity and community composition [GenBank Accession Numbers: HM641909-HM744649], and functional gene microarrays (GeoChip 2.0)(11) were used to assess changes in functional gene distribution. Bacterial and fungal communities were also quantified using real-time PCR.