Biology subjects

Pritsch, K.

Publications and source records attributed to Pritsch, K..

5 recordsLinked to original sources

bioRxiv2025

Improving Seedling Survival for Forest Restorations: A Novel Screening Method to Identify Microbial Allies Against Drought Stress

Improving drought tolerance of tree seedlings by plant growth-promoting microorganisms (PGPMs) is a promising approach for nature-based forest restoration. Identifying suitable microorganisms requires a robust selection, including efficient in planta screenings. We sampled at two forest sites in southern Germany with drought legacies and within a dry period to enhance the probability of isolating drought-tolerant microbes. Metabarcoding of the resident soil community revealed a broad on-site diversity with the potential for diverse plant growth-promoting and stress-resistance traits. We isolated 1,292 bacteria and 59 fungi from fine roots of Norway spruce and European beech. 429 isolates were identified on genus level. The most abundant genera were Paraburkholderia (121) and Bacillus (43) in bacteria and Penicillium (8) and Umbelopsis (8) in fungi. Isolates were scored in vitro for abiotic stress tolerance and plant growth-promoting traits, revealing diverse plant growth-promoting abilities for 31 bacteria and a particularly high stress tolerance for 8 fungi. Importantly, an axenic 24-well-plate system was developed to test the most promising bacteria on spruce seedlings under drought. The system allowed direct comparison of inoculation effects on seedling growth and survival with or without drought application. Two strains improved survival and root length under drought, while six strains significantly promoted plant growth under well-watered conditions. This study represents one of the first larger scale screenings for PGPMs isolated from forest soils on tree seedlings under drought and may contribute to finding nature-based drought mitigation strategies.

microbiology↗

bioRxiv2025

Functional diversity of soil microbial communities increases with ecosystem development

Land abandonment is the single largest process of land-use change in the Global North driving succession and afforestation at continental scales, but assessing its impacts on soil microbial communities remains a challenge. Here, we established a nationwide successional gradient of paired grassland and forest sites to track developments in microbial structure and functioning following land abandonment and gradually changing plant communities. We show that microbes generally respond through threshold dynamics, leading to increasing functional but decreasing taxonomic diversity. Succession also increased the specialization of microbial nutrient (C-N-P) cycling genes while decreasing genetic redundancy, highlighting a putative trade-off between two desirable ecosystem properties: functional diversity and functional redundancy. Increasing fungal functional diversity underpinned higher microbial C-cycling capacity, underscoring the causal link between functional traits and ecosystem processes. Changing litter quality similarly provided a mechanistic link between plant and microbial communities despite otherwise largely decoupled successional developments. Land abandonment is frequently touted as an opportunity to increase biodiversity and carbon storage. Our results show that deeper knowledge about the multifaceted development of soil microbial communities and its links to plant communities during succession may be needed to fully grasp the impacts of global land abandonment processes.

ecology↗

bioRxiv2024

Deciphering plant-beneficial fungal interactions: Unravelling metabolic diversity that underpins communication between Laccaria bicolor and Trichoderma

With over 250 known species, the genus Trichoderma (Ascomycota, Hypocreaceae) is found in various soils, on plant surfaces and as plant endophytes. While Trichoderma species are known as mycoparasites, their antagonistic behaviour can also negatively affect other beneficial fungi, such as mycorrhizal fungi. To gain insight into the metabolic signals involved in the interactions between the ectomycorrhizal fungus (ECM) Laccaria bicolor (Basidomycota, Hydnangiaceae), and different mycoparasitic Trichoderma spp. (T. harzianum strains WM24a1, MS8a1 and ES8g1, and T. atrobrunneum), we performed in vitro dual-confrontation experiments. We studied the volatile organic compounds (VOCs), hyphal metabolomes and soluble metabolites released by each of the fungi in various co-cultivation scenarios. The results revealed an altered growth of the mycelia depending on the degree of contact: When Trichoderma spp. and L. bicolor shared only the same headspace, Trichoderma spp. growth was at least partially inhibited, whereas in direct contact the growth of L. bicolor was impaired. Distinct strain- and species-specific changes in hyphal metabolites, in exudates and volatile emission were revealed from each of the studied fungi. We identified both core metabolite profiles and interaction-specific metabolic responses that were related to carbohydrate, lipid, nucleotide, energy and amino acid metabolisms. Volatile and soluble metabolites revealed temporal and spatial adjustments in dual cultures compared to solitary cultures, suggesting rapid contact-dependent adaptations and demonstrating the dynamic communication mechanisms between Trichoderma spp. and the ECM. These results suggest a central role for both emitted and secreted fungal metabolites in the fungal non-self-recognition and in interaction with each other.

microbiology↗

bioRxiv2023

Responses of root-associated fungal communities of mature beech and spruce during five years of experimental drought

Drought affects the fine-root systems of European beech (Fagus sylvatica L.) and Norway spruce (Picea abies [L.] KARST) in different ways, but little is known about how this impacts their fine-root-associated fungal communities. In a five-year throughfall exclusion experiment (KROOF) in a mature stand, we investigated whether recurrent drought periods progressively alter fine-root associated fungal communities, fine-root vitality, and ectomycorrhizal functionality in relation to the tree root zone (pure beech, pure spruce, or their mixture) and abiotic soil parameters. We found that the influence of recurrent droughts on root fungal communities peaked in the third year of the experiment and affected fungal functional groups in different ways. The root zone was the predominant factor in structuring all functional groups of root-associated fungi, while we did not find a prominent effect of root mixture. The importance of other factors (year of sampling, soil depth) varied among fungal functional groups. Our results indicate a robust biotrophic root-fungal system relying mainly on surviving root tips, complemented by a fluctuating saprotrophic fungal assembly.

ecology↗

bioRxiv2023

Low soil moisture induces recruitment of Actinobacteria in the rhizosphere of a drought-sensitive and Rhizobiales in a drought-tolerant potato cultivar

Growing evidence suggests that soil microbes can improve plant fitness under drought. However, in potato, the worlds most important non-cereal crop, the role of the rhizosphere microbiome under drought has been poorly studied. Using a cultivation independent metabarcoding approach, we examined the rhizosphere microbiome of two potato cultivars with different drought tolerance as a function of water regime (continuous versus reduced watering) and manipulation of soil microbial diversity (i.e., natural (NSM), vs. disturbed (DSM) soil microbiome). Water regime and soil pre-treatment showed a significant interaction with bacterial community composition of the drought-sensitive (HERBST) but not the drought-resistant cultivar (MONI). Depending on the cultivar, different taxa responded to reduced watering. Under NSM conditions, these were mostly rhizobiales order representative in MONI, and Streptomyces, Glycomyces, Marmoricola, Aeromicrobium, Mycobacterium, amongst Actinobacteriota, and the root endophytic fungus Falciphora in HERBST. Under DSM conditions and reduced watering, Bradyrhizobium, Ammoniphilus, Symbiobacterium and unclassified Hydrogenedensaceae responded in the rhizosphere of MONI compared to the continuous, while in HERBST, fewer taxa of Actinobacteriota and no fungi responded to reduced vs. continuous watering. Overall, our results indicate a strong cultivar specific relationship between potato and their associated rhizosphere microbiomes under reduced soil moisture.

ecology↗