Climate change resilience of Prairie oilseed crops and their below-ground microbiota under drought stress in controlled and field environments
Term: 3 years, ending March 2025
Status: Completed
Researchers: Tim Dumonceaux, Jennifer Town, Christina Eynck and Isobel Parkin (AAFC); Bobbi Helgason (University of Saskatchewan); Sean Hemmingsen (National Research Council Canada)
SaskCanola Investment: $167,200
Total Project Cost: $167,200
Project Description
Climate change is presenting challenges to established agronomic practices and can stretch the adaptive capacity of currently available crop cultivars due to extreme weather events such as early and intense heat and drought conditions. Adapting to such challenges within a suitable time frame will require the application of modern tools of plant breeding and genomics for plant improvement, along with the exploitation of existing breeding lines that possess inherent traits conferring resilience to such stresses. While breeding and genomic analysis remain critical tools for crop adaptation to changing conditions, it is also important to consider the contribution of the microbial species that associate with the root systems of crop plants to their resiliency.
Plants excrete compounds (exudates) from their roots that attract and enhance the growth of microorganisms. Thus, plants modify the environment of the rhizosphere, which alters the composition of the rhizosphere microbiome. This can have detrimental or beneficial effects on the plant; these effects can include beneficial interactions that provide some level of adaptive capacity according to plant growth conditions. The microbial component of the agricultural ecosystem therefore represents a resource of genes and metabolic capabilities that must be examined alongside plant genomes to present a complete picture of the plant when grown under conditions of water stress.
The current project aims to complement a federally funded project that will examine the adaptive capacity of existing breeding lines of canola (among other oilseed species) to conditions of drought stress. It will examine the soil, rhizosphere, and root microorganisms that are recruited by canola plants under stress conditions. In addition to relating the recruitment of microbial species to the performance of the examined lines, the project will result in the isolation by culture of microbes (or groups of microbes) that could help plants adapt to the changing conditions currently being experienced on the Canadian Prairies.
Grower Benefits
This project has provided a foundation for establishing the complex interactions between canola and the soil microbiota in response to drought stress. We are exploring the connection among root exudates produced by the plant in response to drought stress, the accumulation of desiccation-resistant bacterial strains in the rhizosphere, and the ecological role of the rhizosphere bacteria in helping the plant contend with the abiotic stress of water deficit. In doing so, we have demonstrated that bacteria that were previously characterized as to be associated with plant growth promotion and drought tolerance are found in the rhizosphere of drought-stressed canola. In addition, we have determined some of their phenotypic attributes that could be related to this activity, including phosphate solubilization.
In characterizing the entire bacterial and fungal microbiota in these plants, we can investigate using statistical methods whether the plant uses deterministic processes to shape its microbiota and recruit beneficial microorganisms because of drought stress. The culture collection that we have begun in this project has yielded strains with potential value and application in agriculture – certainly, that has been demonstrated with other strains of the same bacteria. There remain over 100 strains in the collection to be characterized, with more potential value; for example, we have isolated from the rhizosphere of drought-stressed B. carinata a strain of Bacillus pumilus, which is a known root colonizing, desiccation-tolerant bacterium that is used in agricultural fungicides. This demonstrates that the culture collection contains much potential for agricultural application, even beyond the direct objectives of this project. We expect that this work, begun in the current project, will continue for several years as we connect the various pieces of data we have generated into a coherent picture of the oilseed plant’s response to drought stress through its microbiota.
Objectives
Determination of microbial taxa associated with canola plants using natural soils under water stress. Compositions of root and rhizosphere microbial communities for each line under normal and water-limited conditions will be determined using 16S/ITS amplification. This will be complemented by chaperonin-60 (cpn60) analysis as necessary to provide complete, high-resolution taxonomic profiles of the samples.
Determine the relationship between microbial taxa identified and phenotypic traits. Relationships between microbial community structures and phenotypic traits will be determined, providing critical data on the microbial taxa recruited by crop plants for resilience to and recovery after drought stress. Strain level taxonomic data will guide culture efforts for mechanistic studies and identification and isolation of microbial inoculants.
Refine established methods for analysis of plant root exudates. Methods for sample collection and processing will be expanded and refined to more accurately identify changes in root exudate profiles in response to drought conditions.
Other References to this Research Project
Canola Watch Podcast: Plants, microbes and new tools (January 28, 2022)