| Project Detail |
Background: Suboptimal availabilities of nitrogen (N) and phosphorus (P) in field soils are two of the most limiting factors in agriculture. Mineral fertilization is therefore a primary component of crop production in modern agroecosystems, but the excessive use of external N and P inputs coupled with low nutrient uptake and use efficiencies of many modern cultivars are threatening the environment worldwide. For this reason, it is crucial to invest in novel bio-based technologies to increase resource use efficiency of crops to meet the growing global demand for food in a more sustainable way. There is increasing evidence that the selection of root microbiomes and root phenotypes under N and P deficiency can increase plant productivity and stress resilience, but still little is known about their interaction under stress, and the influence of the plant genotype of ancient and modern crop varieties on both root development and microbiome composition and functioning. Novel approaches to engineer microbiomes in association with specific root phenotypes such as host-mediated indirect selection (HMIS), in combination with advanced molecular technologies such as metagenomics and metabolomics, might be harnessed to select for beneficial combinations of root phenotypes and root microbiomes that optimize nutrient use efficiency under N and P stress.Hypotheses: Specific maize genotypes enhance plant performance under nutrient stress. This effect is associated with specific root traits and the recruitment of selected root microbiomes that have a synergistic effect on plant performance under N and P limitation. This synergism can be harnessed to select for beneficial microbiomes that significantly improve plant tolerance to N and P limitations combined.Objectives: The overall aim of this project is to develop a novel bio-based technology to improve tolerance of maize towards N and P limitation by applying HMIS of microbiomes in synergy with root phenotyping in different ancient and modern maize varieties. The specific objectives are (1) to evaluate the performance of ancient and modern maize genotypes with their root phenotypes and respective root microbiomes under low-input conditions (combined low N/P); (2) to select root microbiomes associated with higher plant performance under low N/P availability via HMIS; (3) to evaluate the effectiveness of the HMIS-selected microbiomes and their relative contribution to plant tolerance under low N/P; and (4) to characterize enriched, potentially beneficial microbial taxa to spur biofertilizer production efforts.Methods: Ancient and modern maize genotypes with known contrasting tolerance to N and P limitation will be grown in mesocosm experiments in the greenhouse providing controlled fertigation with low N/P. Plant nutrient uptake and stress tolerance under low N and P availability will be assessed by measuring plant growth (e.g., leaf nutrient content, biomass), plant nutrient deficiency symptoms (chlorosis, pigmentation, stunted growth), root phenotyping, and leaf/root metabolomics. Recruitment of root-associated microorganisms will be studied using metabarcoding of ribosomal markers and comparative metagenomics to measure differences in taxonomic and functional composition of the microbiomes.Expected results: We expect to (1) observe a significant difference in plant performance, root phenotypes and microbial recruitment between ancient and modern maize lines under stress, (2) select for high-performing microbiomes associated with specific root phenotypes under low N/P stress, and (3) identify enriched predicted functions and potential key taxa within the selected microbiome that can guide biofertilizer production efforts by elucidating the putative physiological requirements of the enriched key taxa via metagenome-assembled genomes.Impact: The application of HMIS in synergy with root phenotyping is a completely novel approach to improve plant tolerance towards multiple stressors and can provide new insights for plant breeding and biofertilizer production for a more sustainable agriculture. This project will provide a replicable approach for improving plant performance under N and P limitations and identify microbial taxa with beneficial traits for plant growth under low-input systems. |
