Project Number: 8072-12000-014-000-D
Project Type: In-House Appropriated
Start Date: Nov 10, 2021
End Date: Nov 9, 2026
Objective 1: Determine the impact of management practices on AMF community dynamics and AMF colonization efficiency of crops, and the resulting impact on crop yield and quality. Sub-objective 1.A: Determine optimal AMF inoculum composition for production of sweet corn and winter squash under organic and conventional management practices. Sub-objective 1.B: Identify the impact of soil microbial dynamics caused by farm management practices on outcomes of AMF inoculations. Objective 2: Determine the physiological and transcriptional responses of AMF to phytochemical signals and environmental conditions promoting spore germination and growth. Sub-objective 2.A: Evaluate whether abietic acid and dehydroabietic acid are signals that activate carbon uptake by AM fungi. Sub-objective 2.B: Evaluate whether hypoxia is a physiologic condition that activates carbon uptake by AM fungi, either acting alone or in combination with signals derived from root exudates.
For Obj. 1A, a greenhouse trial will be conducted to evaluate the infectivity potential of nine different AMF species on sweet corn and winter squash seedlings. Seedlings will be harvested at 10 and 30 days after germination for analysis of root colonization and biomass measurements. Colonization will be measured by root staining/microscopy and molecular methods. Biomass measurements and mineral nutrient content will be analyzed. For Obj. 1B, the three top-performing AMF isolates from 1A will be selected for field trials. Field trials will be conducted within the Rodale Institute’s Vegetable Systems Trial (VST). Tillage systems consist of two organic and two conventional systems, and within each pair one utilizes plastic mulch for weed suppression and the other utilizes a cover crop. Mycorrhizal yield response will be evaluated. The field trial will be repeated a second year, and the results will be used to design a larger field study. For Obj. 2A, spores of R. irregularis will be used in immobilized cell cultre in phytagel M medium with 13C labelled glucose, AA, DHA,and Myr-K media amendments. Growth and sporulation will be monitored. Lipid uptake will be assessed by fluorescence microscopy, and uptake of carbohydrates will be measured by NMR. Based on biomass yield and uptake/labeling of 13C, an RNA-Seq experiment will be designed to capture genes differentially expressed in response to the amendments. For Obj. 2B, spore germination and hyphal growth responses of two AMF species, Gigaspora gigantea and R. irregularis, will be evaluated in response to partially purified root exudates and reduced oxygen conditions (hypoxia). Carbohydrate and lipid uptake will be measured by NMR and fluorescence microscopy as in 2A.