Biology subjects

Jumpponen, A. M.

Publications and source records attributed to Jumpponen, A. M..

4 recordsLinked to original sources

bioRxiv2025

Plant host identity drives Andropogon gerardii rhizobiome assembly strategies under increasing abiotic stress

Predicted changes in precipitation threaten tallgrass prairies by altering the soil microbial communities that are essential for plant resilience. Andropogon gerardii, a dominant grass in tallgrass prairies, spans the contiguous North American precipitation gradient. However, it remains unclear to what extent the rhizosphere microbiomes (rhizobiomes) are influenced by the plant-host environmental interaction. To assess how environmental and host factors shape the rhizobiome, we surveyed A. gerardii populations across 25 remnant prairie sites (June-August 2023) within its native range in the United States, characterizing the microbiomes in the rhizosphere and soils using 16S amplicon sequencing. We demonstrated that while geographic location largely structured both rhizosphere and soil communities, regional precipitation (60-day rainfall) emerged as a primary driver of the microbial community assembly. We observed distinct microbial divides across the dry and wet regions of the North American "arid-humid divide." Importantly, we found the first compelling large-scale evidence that regional precipitation has a profound influence on rhizobiome assembly. In the most arid regions, rhizosphere microbial communities exhibited significantly more predicted stochasticity than those in the local soil and contained taxa related to host-benefiting functions. Our study suggests that intensified host-driven selection for specific microbial variants occurs under heightened abiotic stress, highlighting the hosts pivotal role in shaping its rhizobiome composition in challenging environments.

microbiology↗

bioRxiv2024

Interaction of plant-derived metabolites and rhizobiome functions enhances drought stress tolerance

BackgroundPlants evolved alongside microbes, enabling plants to better cope with abiotic and biotic stresses. The interactions between plant roots and local soil microbes are critical for environmental adaptation and plant health. Plants actively regulate the microbial community composition in their rhizospheres to recruit specific microorganisms that enhance their fitness in the ecosystem they inhabit. This study builds on prior research suggesting that plants have a "home field advantage" in recruiting microbes unique in their home environment, reflecting mutual recognition and the targeted recruitment of microbes. ResultsUsing gene- and genome-centric approaches, we assessed the functional potential of root-associated microbes and profiled the host metabolites to uncover the metabolic outputs potentially regulating host-microbe interactions. Our results showed that plants adapted to drier environments experience less stress, producing fewer stress-related metabolites and impacting the recruitment of microbes with genes linked to stress relief pathways. In particular, plant-derived trimethyllysine was highly associated with microbial populations capable of improving nutrient uptake, producing plant growth-promoting compounds, and modulating stress responses. ConclusionThis study highlights the critical interplay between host exudates and microbial substrate uptake as the primary mechanism of rhizosphere assembly. We demonstrate that plants actively produce metabolites to recruit microbial populations with the functional potential to enhance hosts ability to thrive in a stressful environment. This research provides insights into the mechanisms of plant-microbe communication, rhizosphere recruitment, and the complex interplay of plant-microbe interactions. Furthermore, it highlights promising avenues for manipulating rhizosphere microbiomes to support conservation agriculture in the face of climate change.

microbiology↗

bioRxiv2022

Culturomics of Andropogon gerardii rhizobiome revealed nitrogen transforming capabilities of stress-tolerant Pseudomonas under drought conditions

BackgroundClimate change will result in more frequent droughts that impact soil-inhabiting microbiomes in the agriculturally vital North American perennial grasslands. In this study, we used the combination of culturomics and high-resolution genomic sequencing of microbial consortia isolated from the rhizosphere of a tallgrass prairie foundation grass, Andropogon gerardii. We cultivated the plant host-associated microbes under artificial drought-induced conditions and identified the microbe(s) that might play a significant role in the rhizobiome of Andropogon gerardii under drought conditions. ResultsPhylogenetic analysis of the non-redundant metagenome-assembled genomes (MAGs) identified the bacterial population of interest - MAG-Pseudomonas. Further metabolic pathway and pangenome analyses detected genes and pathways related to nitrogen transformation and stress responses in MAG-Pseudomonas. ConclusionsOur data indicate that the metagenome-assembled MAG-Pseudomonas has the functional potential to contribute to the plant hosts growth during stressful conditions. This study provided insights into optimizing plant productivity under drought conditions.

microbiology↗

bioRxiv2018

Rootstocks shape the rhizobiome: Rhizosphere and endosphere bacterial communities in the grafted tomato system

Root-associated microbes are critical to plant health and performance, although understanding of the factors that structure these microbial communities and theory to predict microbial assemblages are still limited. Here we use a grafted tomato system to study the effects of rootstock genotypes and grafting in endosphere and rhizosphere microbiomes that were evaluated by sequencing 16S rRNA. We compared the microbiomes of nongrafted tomato cultivar BHN589, selfgrafted BHN589, and BHN589 grafted to Maxifort or RST-04-106 hybrid rootstocks. OTU-based bacterial diversity was greater in Maxifort compared to nongraft controls, whereas bacterial diversity in the controls (selfgraft and nongraft) and the other rootstock (RST-04-106) was similar. Grafting itself did not affect bacterial diversity; diversity in the selfgraft was similar to the nongraft. Bacterial diversity was higher in the rhizosphere than in the endosphere for all treatments. However, despite the lower overall diversity, there was a greater number of differentially abundant OTUs (DAOTUs) in the endosphere, with the greatest number of DAOTUs associated with Maxifort. In a PERMANOVA analysis, there was evidence for an effect of rootstock genotype on bacterial communities. The endosphere-rhizosphere compartment and study site explained a high percentage of the differences among bacterial communities. Further analyses identified OTUs responsive to rootstock genotypes in both the endosphere and the rhizosphere. Our findings highlight the effects of rootstocks on bacterial diversity and composition. The influence of rootstock and plant compartment on microbial communities indicates opportunities for the development of designer communities and microbiome-based breeding to improve future crop production.\n\nImportanceUnderstanding factors that control microbial communities is essential for designing and supporting microbiome-based agriculture. In this study, we used a grafted tomato system to study the effect of rootstock genotypes and grafting on bacterial communities colonizing the endosphere and the rhizosphere. Comparing the bacterial communities in control treatments (nongraft and selfgraft plants) with the hybrid rootstocks used by farmers, we evaluated the effect of rootstocks on overall bacterial diversity and composition. These findings indicate the potential for using plant genotype to indirectly select bacterial taxa. In addition, we identify taxa responsive to each rootstock treatments, which may represent candidate taxa useful for biocontrol and in biofertilizers.

microbiology↗