Biology subjects

Jansa, J.

Publications and source records attributed to Jansa, J..

4 recordsLinked to original sources

bioRxiv2024

Strong family- and guild-specific responses of arbuscular mycorrhizal fungi to long-term deficiencies and imbalances of N, P and K

O_LIMany agroecosystems face nitrogen (N), phosphorus (P) or potassium (K) deficiencies due to imbalanced or insufficient nutrient replenishment after plant biomass harvest. How this affects the symbiosis between plants and arbuscular mycorrhizal fungi (AMF), and the abundance of exploration-based AMF guilds (i.e., rhizophilic, edaphophilic, ancestral) remains largely unknown. C_LIO_LIWe studied a 70-year nutrient-deficiency experiment in a managed grassland in central Austria, where aboveground biomass was harvested three times annually. N, P and K were fully, partially, or not replenished, causing long-term nutrient deficiencies and imbalances. We analysed AMF communities in soil and roots by DNA/RNA amplicon sequencing and fatty-acid biomarkers, alongside soil and plant community properties. C_LIO_LISoil AMF communities were affected by N and P deficiencies, while root AMF communities were most susceptible to K deficiency, showing a 50% biomass reduction. We observed distinct guild- and family-specific responses: The edaphophilic guild declined with N deficiency, while the rhizophilic guild decreased with P and K deficiencies. Families within each guild, particularly in the ancestral guild, showed differential responses, indicating complementary nutrient specializations at the family level. C_LIO_LIOur findings underscore the previously unrecognized role of K deficiency in AMF symbiosis and suggest the existence of nutrient-related functional subgroups within exploration-based AMF guilds. C_LI

ecology↗

bioRxiv2024

Strategies of resource sharing in clonal plants: A conceptual model and an example of contrasting strategies in two closely related species

Background and AimsClonal growth helps plants to cope with environmental heterogeneity through resource integration via connecting organs. Such integration is considered to balance heterogeneity by the translocation of resources from rich to poor patches. However, such an equalisation strategy is only one of several possible strategies, as we discuss in a brief conceptual analysis. Under certain conditions, a strategy emphasising acropetal movement and exploration of new areas or a strategy accumulating resources in older ramets may be preferred. The optimal strategy may be determined by environmental conditions, such as resource availability and level of light competition. Therefore, species from different habitats may exhibit distinct resource translocation strategies. MethodsResource translocation was compared between two closely related species from different habitats with contrasting productivity. The study examined the bidirectional translocation of carbon and nitrogen in pairs of mother and daughter ramets grown under light heterogeneity (one ramet shaded) at two developmental stages using stable-isotope labelling. Key resultsAt the early developmental stage, both species translocated resources toward daughters and the translocation was modified by shading. Later, the species of low-productivity habitats, Fragaria viridis, translocated carbon to shaded ramets, according to the equalisation strategy. The species of high-productivity habitats, Potentilla reptans, did not support shaded older ramets. Nitrogen translocation remained mainly acropetal in both species. These findings confirmed our expectations. ConclusionsThe two studied species exhibited different translocation strategies, which may be linked to the habitat conditions experienced by each species. The equalisation strategy may occur in habitats with lower productivity and lower light competition, than the strategy emphasising acropetal movement. The results indicate that we need to consider different possible strategies. We emphasise the importance of bidirectional tracing in translocation studies and the need for further studies to investigate the translocation patterns in species from contrasting habitats.

ecology↗

bioRxiv2023

Constraining activity and growth substrate of fungal decomposers via assimilation patterns of inorganic carbon and water into lipid biomarkers

Fungi are among the few organisms on the planet that can metabolize recalcitrant C but are also known to access recently produced plant photosynthate. Therefore, improved quantification of growth and substrate utilization by different fungal ecotypes will help to define the rates and controls of fungal production, the cycling of soil organic matter, and thus the C storage and CO2 buffering capacity soil ecosystems. This study combined a dual stable isotope probing approach together with rapid analysis by tandem pyrolysis gas chromatography isotope ratio mass spectrometry (Pyr-GC-IRMS) to determine the patterns of water-derived hydrogen (H) and inorganic C assimilated into lipid biomarkers of heterotrophic fungi as a function of C substrate. The water H assimilation factor (w) and the inorganic C assimilation for C18:2 fatty acid isolated from five fungal species growing on glucose was lower (0.62{+/-}0.01 and 4.7{+/-}1.6%, respectively) than for species grown on glutamic acid (0.90{+/-}0.02 and 7.4{+/-}3.7%, respectively). Furthermore, the assimilation ratio (RIC/W) for growth on glucose and glutamic acid can distinguish between these two metabolic modes. This dual SIP assay thus delivers estimates of fungal activity and may help to delineate the predominant substrates that are respired among a matrix of compounds found in natural environments. (200 Words) ImportanceFungi decomposers play important roles in food webs and nutrient cycling because they can feed on both labile and stable forms of carbon. This study developed and applied a dual stable isotope assay to improve the investigation of fungal activity in the environment. By determining the incorporation patterns of hydrogen and carbon into fungal lipids, this assay delivers estimates of fungal activity and the different metabolic pathways that they employ in ecological and environmental systems. (75 Words)

microbiology↗

bioRxiv2019

Correlative evidence for co-regulation of phosphorus and carbon exchanges with symbiotic fungus in the arbuscular mycorrhizal Medicago truncatula

In the research of arbuscular mycorrhizal (AM) symbiosis a considerable progress was made. But despite that, key questions still remain unanswered - for example it is well known that biotrophic fungus release phosphate (P) to- and recieves carbon (C) from the plant symbiont, but the particular genes, and their products, responsible for this exchange are still not fully understood. Here, we made a de novo quest for such genes involved in C transfer. Using physiological intervention of 90% shading and the correlation of expression levels of MtPT4, the AM-specific marker, and our candidate genes we demonstrate that several novel genes may be involved in AM symbiosis in Medicago truncatula. Also, we examined the expression of phosphate transporters (MtPT1-6) and we discuss the balance of \"direct\" and \"mycorrhizal\" P uptake pathways upon symbiotic fungus infection and C deprivation.

plant biology↗