Ammonia-oxidizing microbial community dynamics under different mineral and fertilization management

Non-Peer Reviewe

How mycorrhizal fungal bio-fertilizer impact on seed yield of field pea and wheat across Saskatchewan prairies

Non-Peer Reviewe

Endophytic Fungus, TSTh20-1, promotes plant growth on oil sands tailings

Non-Peer Reviewe

Endophytes modulate drought tolerance in pulses by scavenging reactive oxygen species in plant cells under drought stress

Non-Peer Reviewe

Proliferation of mycorrhizal fungal species on organic matter improves nitrogen nutrition in Russian wild rye

Non-Peer ReviewedArbuscular mycorrhizal fungi (AMF) facilitate plant growth by aiding nutrient movement to plants especially under low fertility conditions. Arbuscular mycorrhizal fungi generally takes N as NH4+ or NO3-. We hypothesized that AMF enhance soil organic matter decomposition through their stimulating influence on soil microorganisms and help in the transport of nitrogen to plants. Hyphal chambers (HC) containing labelled 15N organic matter (wheat root and shoot) were inserted in pots. Russian wild rye was inoculated or not with three AM fungal species (G. intraradices, G. claroideum, G. clarum) and was grown for six months. The amount of total C retained in the HC was lower in the presence of AMF hyphae as compared to control and substrate C:N ratio was lower indicating that decomposition was faster in AMF colonized systems. The faster rate of decomposition in HC in presence of AMF was concurrent with change in microbial community structure. Higher N uptake and greater plant biomass were measured in AMF treated Russian wild rye as compared to control. Results of the present investigation suggest that presence of AMF hastens organic matter decomposition, thus enhancing soil N fertility and plant growth

Influence of urease and nitrification inhibitors on ammonium and nitrate supply and the soil microbial population in western Canadian soils

Non-Peer ReviewedImproving nitrogen use efficiency and limiting losses of N from the soil system is important both economically and environmentally. This study assessed the potential of using a urease inhibitor, Agrotain®, or a nitrification inhibitor, nitrapyrin, to create a slow release effect similar to that found in sulfur coated urea in western Canadian soils of the Brown and Black soil zones. The nitrapyrin significantly reduced the cumulative NO3- supply to the point of inhibition of nitrification for 21d in the Brown soil, but had little effect on the Black soil. Nitrapyrin had little effect on the supply of NH4+ in both soils. The Agrotain® had some effect on NO3- supply and significantly reduced the NH4+ supply for 14d in the Brown soil. Differences between the two soils were consistent with results in other studies and attributed to pH and organic matter content differences. The total heterotrophic and Nitrosomonas microbial populations were enumerated using spread plates and most probable number assays. It was concluded that Agrotain® had little effect on the microbial population, where as nitrapyrin reduced Nitrosomonas populations and increased total heterotrophic counts in both soils. Similarity between the results in this study and the literature suggest that the soils in Western Canada have similar responses to inhibitors as those characterized by the literature. Therefore, whether improved nitrogen use efficiency from the use of inhibitors in wheat in Western Canada would be large enough to justify the used of inhibitors will depend on whether local soil properties are conducive to promote volatilization, leaching and denitrification losses of N

Microbial communities associated with wheat, canola and lentil seeds produced in Saskatchewan

Non-Peer ReviewedCereals, oilseeds and legumes are staple crops in the Canadian Prairies that significantly contribute to global food supply. Microbial communities naturally carried by seeds offer the potential of improving crop production and yield through protection against abiotic and biotic factors. In this study, we assessed five cultivars/lines of each crop grown under different conditions (location, year) in Saskatchewan to investigate factors responsible for the seed microbiome assemblage. Our data reveal that crop type represented the largest source of variation for both bacterial (30%) and fungal communities (47%), while environment explained an additional 10% and 15%, of the microbial community variance. Additionally, in every sample analyzed, a core microbiome was detected consisting of five bacterial and twelve fungal amplicon sequence variants . Increasing our knowledge of assembly and dynamics of the seed microbiota will lead to better strategies for manipulating the plant microbiome through breeding, inoculation, and crop production practices in order to assure sustainable agriculture systems

Depth differential colonization by mycorrhizal fungi in prairie grasses

Non-Peer ReviewedA research was conducted in field plots to evaluate types of mycorrhizal fungi colonization in monocultures of green needlegrass (G), switch grass (S), western wheatgrass (W), Russian wild rye (R), crested wheatgrass (C) or mixtures of grasses. A root sampling strategy based on different soil depth (0-15, 15-30 and 30-45 cm) revealed a significant effect of depth on root colonization by different types of mycorrhizal fungi, but no significant differences were found between plant communities

Elucidating the mystery of the tripartite symbiosis plant – mycorrhizal fungi – dark septate endophytes

Non-Peer ReviewedThis study provides information on the tripartite symbiotic relationships formed by arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSE) in crops growing in the semiarid region of the Canadian Prairie. We found the symbiotic root systems of wheat, pea, chickpea and lentil to be morphologically distinct. The relationship between DSE and AMF abundance in roots ranged from negative in lentil to positive in wheat

Influence of pulse crops on arbuscular mycorrhizal fungi in a durum-based cropping system

Non-Peer ReviewedPulses are an important component in crop rotations in southern Saskatchewan. Besides their capability to fix nitrogen, pulse crops establish a symbiotic relationship with arbuscular mycorrhizal fungi, which have been shown to increase nutrient and water uptake through hyphal extensions in the soil. This 2 year study is designed to evaluate the impact of pulses in crop rotations on the biodiversity of AMF communities and their dynamics. Plant N and P uptake and the available soil N and P pools under a durum crop are also measured to assess if there is any correlation with AMF communities. The sampling and analysis is completed on the durum phase of the rotation with preceding crops of pea, lentil, chickpea, canola and durum. The final results will be explained by: (1) the size, nature, and physiological state of the soil microbial community and (2) the nature of the preceding crop residues. Preliminary results from the 2004 season indicate that higher plant P uptake is related to AMF colonization, while no significant change was detected in the soil N and P pools