Plant-mycorrhizal-decomposer interactions under climate change: the role of shifting plant carbon allocation
EMSL Project ID
51536
Abstract
Ectomycorrhizal fungi (EMF) that associate with the roots of live plants can control the growth rate of their hosts and the amount of nutrients and carbon (C) that are recycled through soil (e.g., as CO2 respired to the atmosphere) during decomposition by free-living saprotrophic decomposers (SAPs). The goal of our project is to identify the molecular mechanisms by which plant-EMF-SAP interactions control fluxes of C and nutrients through terrestrial ecosystems. Our recent collaborative studies with JGI and EMSL show that EMF-SAP interactions are dependent on soil C and N availability. However, plants provide sugar-C to their EMF symbionts in exchange for soil nutrients like nitrogen (N), which could strongly influence interactions between EMF and SAPs. In this project, we aim to explore how elevated CO2 conditions that increase plant C allocation belowground impact EMF-SAP interactions and the ability of EMF to mine for soil N. We expect that increased plant C availability to EMF (through elevated atmospheric CO2) intensifies EMF competition with SAPs for soil N, reducing the efficiency of N acquisition by EMF and increasing the plant C cost of N uptake. We propose to work with JGI, EMSL and NSLS-II/BNL to characterize elevated CO2 effects on plant-EMF-SAP interactions in a model Suillus-Pinus paired system using SIP metagenomics/metatranscriptomics (JGI), metaproteomics (EMSL), chemical imaging (EMSL, BNL), and spatially resolved gene expression (EMSL). To do so, we are implementing a novel greenhouse-based synthetic ecosystem that uses distinct 13C isotope profiles of C3 Pinus plants and soils derived from C4 plants to partition soil respiration between EMF roots vs. soil organic matter decomposition. To understand the molecular mechanisms by which C and N cycle through the plant-EMF-SAP system under elevated CO2, we request sequencing resources for 1Tb of 150PE Illumina RNAseq, cDNA library construction, and data analysis through comparative metranscriptomics (24 soil and 24 root samples) from JGI, as well as metaproteomics (72 soil samples) from EMSL and both GC-MS and NMR-based metabolomics (72 soil samples and 72 root samples). We also request SIP metagenomics (24 soils samples, JGI), Nanosims (24 root samples, EMSL), MALDI-FTICR MS (24 root samples and 24 hyphal samples, EMSL), and Fluorescence In Situ Hybridization (FISH) of mRNA (CARD-FISH; 24 root samples and 24 hyphal samples, EMSL) to link rhizosphere C and N cycling to specific redox-based EMF decomposition processes detected through Full-field fluorescence imaging (FFFI; 24 samples, NSLS-II/BNL).
Project Details
Project type
FICUS Research
Start Date
2020-10-01
End Date
2023-04-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members