Manitoba Heritage Theses

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http://hdl.handle.net/1993/3098
Contains full text Manitoba-related theses dating from 1902 to the present.

The University of Manitoba Libraries gratefully acknowledges the financial support of the Manitoba Department of Heritage, Culture, Tourism and Sport in the digitization of many of these theses.

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Browsing Manitoba Heritage Theses by Subject "16S rRNA gene sequencing"

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    Characterization of bacterial communities in soybean cultivated soils of Manitoba
    (2024-12-26) Shayanthan, Ambihai; Hausner, Georg (Microbiology); Bakker, Matthew (Microbiology); Lawley, Yvonne (Plant science); Dunfield, Kari (University of Guelph); Oresnik, Ivan
    Soybean (Glycine max L.) is a legume plant that serves as a rich source of oil and protein. Soybean is well-known for its symbiotic relationship with the bacteria Bradyrhizobium japonicum, which supplies the plant with reduced nitrogen. Although the molecular aspects of this symbiotic relationship are well understood, the structure of bacterial communities in the root-associated soils and the factors influencing their composition have not been extensively studied. This study aims to characterize the bacterial communities of soybean grown in two different field experiments in Manitoba (Carman and Kelburn) with four different crop rotations: continuous soybean (CS), soybean-canola (SCa), soybean-corn (SCo), and soybean-wheat-canola-corn (SWCC) from 2017 to 2021. Soil samples were collected four times during the growing season; before planting (BP), emergence (VE), beginning of seed fill (R5), and full maturity (R8). DNA was extracted from the soil samples and subjected to 16S rRNA gene sequencing. In a separate experiment, subsamples were cultured to preserve a local culture collection and to isolate phosphate-solubilizing bacteria (PSB) through targeted culturing. 16S rRNA gene sequencing revealed that soil bacterial diversity was primarily influenced by soil type, with crop rotation inducing short-term changes. Despite environmental variability, crop rotations significantly affected bacterial diversity and composition. Culturing resulted in a total of 262 bacterial strains being added to a culture library. Eight strains, including Paraburkholderia strydomiana, Paraburkholderia graminis, and Burkholderia ambifaria, were identified for their ability to solubilize Ca3(PO4)2. Paraburkholderia strydomiana strains promoted seedling growth, whereas P. graminis and B. ambifaria had negative effects on soybean seedlings. These findings enhance our understanding of bacterial diversity in crop rotation systems and suggest directions for future synthetic community research.