Crop rotation affects the structure and diversity of soil pathogenic and non-pathogenic microbial communities.
Citation
CROP ROTATION AFFECTS THE STRUCTURE AND DIVERSITY OF SOIL PATHOGENIC AND NON-PATHOGENIC MICROBIAL COMMUNITIES
M. Nazrul Islam1, Randy Kutcher2, Xiben Wang1
1&3Agriculture and Agri-Food Canada, Morden Research and Development Centre, Morden, Manitoba, 2College of Agriculture and Bioresources, University of Saskatchewan, Saskatoon, Canada
Résumé en langage clair
Crop rotations are one of the most desirable alternatives to disease management in Canada and elsewhere in the world. But very limited studies have demonstrated the impact of rotations on the major soil-borne diseases/pathogens and the role of nonpathogenic microbiomes in suppressing crop diseases across the prairies. During the 2021 cropping season, soil samples (rhizosphere soils at crop flowering and bulk soils at crop harvest) were collected from Morden (Black Chernozem soils), Manitoba and Saskatoon (Dark Brown Chernozem soils), Saskatchewan experimental field sites. The effect of nine treatment combinations of cereals (wheat, barley, maize)-pulses (pea, soybean)-oilseeds (canola) on the composition, abundance (frequency), Shannon diversity and operational taxonomic units/OTUs richness of microbiomes were assessed. We characterized microbiomes by high-throughput targeted metagenomics sequencing of ITS (fungi) and 16S (bacteria) rRNA genes. The bioinformatics for taxonomic profiling and diversity index was performed using the QIIME 2™ platform. Multivariate statistics revealed that rotational (combination of cereals-pulses-oilseeds) treatments significantly modified both fungal and bacterial communities. We also evaluated the impact of two-year crop rotations (2020-2021) on the relative abundance of Fusarium head blight of cereals (F. graminearum), blackleg of canola (Leptosphaeria maculans), storage molds (Alternaria spp.) and common root rot (Fusarium and Rhizoctonia spp.) pathogens. In future research, it is imperative to understand the impact of crop rotations not only on major soil-borne pathogens but also on the production of diseases suppressive microbial genes/communities (e.g., bacteria) known as natural biocontrol microbes and their interactions in the prairie crop soils.
Résumé
Crop rotations are one of the most desirable alternatives to disease management in Canada and elsewhere in the world. But very limited studies have demonstrated the impact of rotations on the major soil-borne diseases/pathogens and the role of nonpathogenic microbiomes in suppressing crop diseases across the prairies. During the 2021 cropping season, soil samples (rhizosphere soils at crop flowering and bulk soils at crop harvest) were collected from Morden (Black Chernozem soils), Manitoba and Saskatoon (Dark Brown Chernozem soils), Saskatchewan experimental field sites. The effect of nine treatment combinations of cereals (wheat, barley, maize)-pulses (pea, soybean)-oilseeds (canola) on the composition, abundance (frequency), Shannon diversity and operational taxonomic units/OTUs richness of microbiomes were assessed. We characterized microbiomes by high-throughput targeted metagenomics sequencing of ITS (fungi) and 16S (bacteria) rRNA genes. The bioinformatics for taxonomic profiling and diversity index was performed using the QIIME 2™ platform. Multivariate statistics revealed that rotational (combination of cereals-pulses-oilseeds) treatments significantly modified both fungal and bacterial communities. We also evaluated the impact of two-year crop rotations (2020-2021) on the relative abundance of Fusarium head blight of cereals (F. graminearum), blackleg of canola (Leptosphaeria maculans), storage molds (Alternaria spp.) and common root rot (Fusarium and Rhizoctonia spp.) pathogens. In future research, it is imperative to understand the impact of crop rotations not only on major soil-borne pathogens but also on the production of diseases suppressive microbial genes/communities (e.g., bacteria) known as natural biocontrol microbes and their interactions in the prairie crop soils.