$2.2 billion annually in the US alone, and we currently lack sustainable ways to enhance plant N and P uptake for high yield crop production. If the application of these fertilizers can be controlled (supplied at rate of plant's need) or circumvented, smaller amounts could be applied to achieve the same yields, or plants may be able to grow on marginal soils, expanding the footprint of crop production. In addition to the fertilizer crisis, drought events are threatening the global food supply chain because the depletion of water availability in soil has negative impacts on crop growth. Currently, it is estimated that agricultural irrigation accounts for 70% of global water use and about 40% of that is lost due to seepage and evaporation. The increase in drought occurrences also taxes water systems to meet the demand of agricultural irrigation. It becomes essential to find sustainable fertilizer alternatives and increase the water retention in soils.' />
Source: UNIVERSITY OF WASHINGTON submitted to NRP
HARNESSING SYNERGISTIC BACTERIAL-FUNGAL INTERACTIONS IN HYDROGEL BIOFERTILIZERS TO PROMOTE SUSTAINABLE AGRICULTURAL PRACTICES
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
ACTIVE
Funding Source
AFRI COMPETITIVE GRANT
Reporting Frequency
Annual
Accession No.
1030752
Grant No.
2023-67013-40171
Cumulative Award Amt.
$849,392.00
Proposal No.
2022-11100
Multistate No.
(N/A)
Project Start Date
Sep 16, 2023
Project End Date
Sep 15, 2026
Grant Year
2023
Program Code
[A1402]- Agricultural Microbiomes in Plant Systems and Natural Resources
Recipient Organization
UNIVERSITY OF WASHINGTON
4333 BROOKLYN AVE NE
SEATTLE,WA 98195
Performing Department
(N/A)
Non Technical Summary
Efficient agricultural management and sustainable practices are needed to meet national food security. Nitrogen (N) and phosphorus (P) fertilization are currently indispensable for high crop yield. However, industrial ammonia production is an energy-intensive process, consuming ~2% of the world's energy and producing ~1% of atmospheric CO2. A majority of P comes from mined rock phosphate; a non-renewable resource that has several major negative impacts, including scarce resource demands, environmental degradation, and geopolitical instability. Overuse of N and P fertilizers, when many crops have low N uptake efficiency (NUE) and P uptake efficiency (PUE), leads to environmental deterioration through leaching and greenhouse gas emissions as N2O through microbial mediated N cycling. This results in groundwater contamination, surface water eutrophication, and air pollution. These environmental damages have been estimated to cost >$2.2 billion annually in the US alone, and we currently lack sustainable ways to enhance plant N and P uptake for high yield crop production. If the application of these fertilizers can be controlled (supplied at rate of plant's need) or circumvented, smaller amounts could be applied to achieve the same yields, or plants may be able to grow on marginal soils, expanding the footprint of crop production. In addition to the fertilizer crisis, drought events are threatening the global food supply chain because the depletion of water availability in soil has negative impacts on crop growth. Currently, it is estimated that agricultural irrigation accounts for 70% of global water use and about 40% of that is lost due to seepage and evaporation. The increase in drought occurrences also taxes water systems to meet the demand of agricultural irrigation. It becomes essential to find sustainable fertilizer alternatives and increase the water retention in soils.
Animal Health Component
40%
Research Effort Categories
Basic
60%
Applied
40%
Developmental
0%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
10201101070100%
Knowledge Area
102 - Soil, Plant, Water, Nutrient Relationships;

Subject Of Investigation
0110 - Soil;

Field Of Science
1070 - Ecology;
Goals / Objectives
he proposed research aims to increase crop yield by creating a sustainable biofertilizer that supplies plants with a mix of mutualistic fungi and beneficial microbes embedded in biodegradable hydrogel beads. Hydrogels will be designed as a highly functional and drought resilient soil amendment as they can absorb water and slowly release it, thus reducing soil moisture loss. Further, they can immobilize beneficial microbes and arbuscular mycorrhizal fungi (AMF), which helps avoid system washout while keeping the consortium near the plant rhizosphere. AMF are obligate mutualists that associate with a majority of crops, and can increase the plant's ability to access and absorb soil N and P while also improving plant water uptake, hence benefitting plant growth while reducing losses to surrounding environments and reducing water pollution. The hydrogel beads will include: a) N-fixing bacteria that can excrete atmospherically fixed N2 in a plant available form (ammonium) and have plant growth promoting effects; and b) phosphate solubilizing bacteria can release bound P in soils making it available for plant uptake. Together, the AMF and bacterial consortium hold potential to reduce the amount of N and P fertilizer, or alleviate it's use completely while still increasing plant N and P uptake.
Project Methods
This project takes advantage of expertise in bacterial-fungal-plant interactions and polymer science to implement a game-changing path to increase our fundamental understanding of how bacterial-fungal hydrogels can benefit plant N and P uptake to increase crop yield while dampening the negative effects of conventional fertilizers. The foremost aims are to investigate the substrate and nutrient exchange in addition to spatio-temporal interactions in hydrogels populated with: a) N-fixing bacteria, b) P-solubilizing bacteria, and c) AMF, to test if these cultures can enhance plant growth. These aims will be achieved by entrapment of these organisms in hydrogels, expanding the gained knowledge to guide new soil amendment strategies, and broadening applicability of the engineered hydrogel approach that also adds drought resistance to soils.?

Progress 09/16/23 to 09/15/24

Outputs
Target Audience:We have incorporated a PhD student hire into the project, which targets our future generation of agricultural scientists with a focus on their training. We have initiated sharing our projectefforts with the greater scientific community through a recent publication in the Journal of Applied Microbiology, as well as numerous oral presentations to academic communities (e.g., the International Mycological Congress) andindustry companies. Theprogress on this research has also been shared widely in guest lectures/invited talks in various departments atthe University of Washington, which has resulted in 6 undergraduates joining the project to gainresearch credits/experience at the intersection ofagricultural ecology and microbiology. The assembly of this team does not only meet the goal of getting young students excited about researchand the pursuit of potential careers inthe agricultural space, but it also supports our DEIA efforts, which are an important mission encompassed within this grant.Out of the undergraduate volunteers and the PhD student, 5out of 7 are from traditionally under-represented backgrounds/minority groups.In addition, the postdoctoral researcher (and Co-I) that is incorporating into this project is also a woman of color with hidden disabilities. Changes/Problems:Some delays in hiringand subcontracting might require a no cost extension but the project goals are still on target in terms of planned milestones as such that we are confident to get the work done but timeline will be somewhat shifted. What opportunities for training and professional development has the project provided?Based on the goals of this USDA grant, we were successful in receiving an internal University of Washington Grant from the Program on Climate Change and a external grant from Washington Research Foundation. This allowed us to hire sixpaid undergraduate associates through the Summer of 2026. Over the last several months, they have received training in a range of greenhouse and lab techniques and mentorship within the academic setting. Additionally, Dr. Korena Mafune is progressing in her professional development as an early-career scientist through these mentorship opportunities. On top of this, Dr. Winkler's and Dr. Mafune's engagement with various courses has pulled the attention of additional undergraduates who want to learn about and conduct research in the agricultural soil microbiology space. How have the results been disseminated to communities of interest?Dr. Korena Mafune disseminated results at the 2023 and 2024 Mycological Society of America's Annual meeting, and she has also given 7 guest lectures that emphasize the importance of this research to various ecology and engineering courses within the UW. Additionally, she will be sharing new results in an oral presentation at the International Mycological Congress meeting in the Netherlands. She also integrated some of our findings into an invited seminar workshop at a circular economy conference that took place in Seattle. Additionally, one of the undergraduates that Dr. Korena Mafune and Dr. Winkler are supervising presented some of the results at the UW undergraduate research symposium and will present results (accepted oral presentation) at the National Sustainability Society Conference in Sept 2024. Further, some results and conceptualization have been discussed with local farmers and other land managers, and they are eager to start trials and collaborations on different crops. What do you plan to do during the next reporting period to accomplish the goals?Delays in the processing of subcontracts have halted progress planned with collaborators at Oklahoma State University and now that this contract is in place we are starting to scope out the interactions as described in the proposal. We also successfully onboarded the PhD student hired for this project, so a large-scale greenhouse study will be up and running over the next few months as we work through the project goals.

Impacts
What was accomplished under these goals? We currently have a published manuscript in the Journal of Applied Microbiology titled: 'Building blocks towards sustainable biofertilizers: Variation in arbuscular mycorrhizal spore germination when immobilized with diazotrophic bacteria in biodegradable hydrogel beads' (abstract below). This manuscript highlights the fundamental importance of microorganism compatibility in the hydrogel environment, and the results inform our future experimental design plans. Aim: To investigate if there was interspecies and intraspecies variation in spore germination of twelve strains of arbuscular mycorrhizal fungi when co-entrapped with the diazotrophic plant growth promoting bacteria, Azospirillum brasilense Sp7 in alginate hydrogel beads. Methods and results: Twelve Rhizophagus irregularis, Rhizophagus intraradices, and Funneliformis mosseae strains were separately combined with a live culture of Azospirillum brasilense Sp7. Each fungal-bacterial consortia was supplemented with sodium alginate to a 2% concentration (v/v) and cross-linked in calcium chloride (2% w/v) to form biodegradable hydrogel beads. 100 beads from each combination (total of 1,200) were fixed in solidified modified Strullu and Romand media. Beads were observed for successful spore germination and bacterial growth over 14 days. In all cases, successful growth of A. brasilenses was observed. For arbuscular mycorrhizal fungi, interspecies variation in spore germination was observed, with R. intraradices having the highest germination rate (64.3%), followed by R. irregularis (45.5%) and F. mosseae (40.3%). However, a difference in intraspecies germination was only observed among strains of R. irregularis and F. mosseae. Despite having varying levels of germination, even the strains with the lowest potential were still able to establish with the plant host Brachypodium distachyon in a model system. Conclusions: Arbuscular mycorrhizal spore germination varied across strains when co-entrapped with a diazotrophic plant-growth promoting bacteria. This demonstrates that hydrogel beads containing a mixed consortium hold potential as a sustainable biofertilizer and that compatibility tests remain an important building block. Significance and impact of study: Sustainable alternatives to conventional fertilizers are greatly needed. This research provides fundamental information that focuses on the potential to harness bacterial-fungal interactions in biodegradable hydrogel beads with the goal of applying them as biofertilizer.

Publications

  • Type: Journal Articles Status: Accepted Year Published: 2024 Citation: Mafune, K. K., Kasson, M. T., & Winkler, M. K. H. (2024). Building blocks toward sustainable biofertilizers: variation in arbuscular mycorrhizal spore germination when immobilized with diazotrophic bacteria in biodegradable hydrogel beads. Journal of Applied Microbiology, 135(7).
  • Type: Conference Papers and Presentations Status: Other Year Published: 2024 Citation: Mafune, K. K., Winkler, M. K. H. 2024. Mixed bacterial-fungal consortia in hydrogel beads maintains grain yield in common wheat (triticum aestivum) while promoting a closed-loop nitrogen cycle.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2024 Citation: Mafune, K.K., Kasson, M. T., Randall, R., Rogers, J., Winkler, M. K. H. 2024. The beneficial impact of mixed bacterial-fungal hydrogel biofertilizers on mycorrhization of Triticum aestivum roots: A greenhouse study